// SPDX-License-Identifier: GPL-2.0
/*
 * IOMMU API for ARM architected SMMUv3 implementations.
 *
 * Copyright (C) 2015 ARM Limited
 *
 * Author: Will Deacon <will.deacon@arm.com>
 *
 * This driver is powered by bad coffee and bombay mix.
 */

#include <linux/acpi.h>
#include <linux/acpi_iort.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
#include <linux/dma-iommu.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io-pgtable.h>
#include <linux/iommu.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_platform.h>
#include <linux/pci.h>
#include <linux/pci-ats.h>
#include <linux/platform_device.h>

#include <linux/amba/bus.h>

/* MMIO registers */
#define ARM_SMMU_IDR0                   0x0
#define IDR0_ST_LVL                     GENMASK(28, 27)
#define IDR0_ST_LVL_2LVL                1
#define IDR0_STALL_MODEL                GENMASK(25, 24)
#define IDR0_STALL_MODEL_STALL          0
#define IDR0_STALL_MODEL_FORCE          2
#define IDR0_TTENDIAN                   GENMASK(22, 21)
#define IDR0_TTENDIAN_MIXED             0
#define IDR0_TTENDIAN_LE                2
#define IDR0_TTENDIAN_BE                3
#define IDR0_CD2L                       (1 << 19)
#define IDR0_VMID16                     (1 << 18)
#define IDR0_PRI                        (1 << 16)
#define IDR0_SEV                        (1 << 14)
#define IDR0_MSI                        (1 << 13)
#define IDR0_ASID16                     (1 << 12)
#define IDR0_ATS                        (1 << 10)
#define IDR0_HYP                        (1 << 9)
#define IDR0_COHACC                     (1 << 4)
#define IDR0_TTF                        GENMASK(3, 2)
#define IDR0_TTF_AARCH64                2
#define IDR0_TTF_AARCH32_64             3
#define IDR0_S1P                        (1 << 1)
#define IDR0_S2P                        (1 << 0)

#define ARM_SMMU_IDR1                   0x4
#define IDR1_TABLES_PRESET              (1 << 30)
#define IDR1_QUEUES_PRESET              (1 << 29)
#define IDR1_REL                        (1 << 28)
#define IDR1_CMDQS                      GENMASK(25, 21)
#define IDR1_EVTQS                      GENMASK(20, 16)
#define IDR1_PRIQS                      GENMASK(15, 11)
#define IDR1_SSIDSIZE                   GENMASK(10, 6)
#define IDR1_SIDSIZE                    GENMASK(5, 0)

#define ARM_SMMU_IDR3                   0xc
#define IDR3_RIL                        (1 << 10)

#define ARM_SMMU_IDR5                   0x14
#define IDR5_STALL_MAX                  GENMASK(31, 16)
#define IDR5_GRAN64K                    (1 << 6)
#define IDR5_GRAN16K                    (1 << 5)
#define IDR5_GRAN4K                     (1 << 4)
#define IDR5_OAS                        GENMASK(2, 0)
#define IDR5_OAS_32_BIT                 0
#define IDR5_OAS_36_BIT                 1
#define IDR5_OAS_40_BIT                 2
#define IDR5_OAS_42_BIT                 3
#define IDR5_OAS_44_BIT                 4
#define IDR5_OAS_48_BIT                 5
#define IDR5_OAS_52_BIT                 6
#define IDR5_VAX                        GENMASK(11, 10)
#define IDR5_VAX_52_BIT                 1

#define ARM_SMMU_CR0                    0x20
#define CR0_ATSCHK                      (1 << 4)
#define CR0_CMDQEN                      (1 << 3)
#define CR0_EVTQEN                      (1 << 2)
#define CR0_PRIQEN                      (1 << 1)
#define CR0_SMMUEN                      (1 << 0)

#define ARM_SMMU_CR0ACK                 0x24

#define ARM_SMMU_CR1                    0x28
#define CR1_TABLE_SH                    GENMASK(11, 10)
#define CR1_TABLE_OC                    GENMASK(9, 8)
#define CR1_TABLE_IC                    GENMASK(7, 6)
#define CR1_QUEUE_SH                    GENMASK(5, 4)
#define CR1_QUEUE_OC                    GENMASK(3, 2)
#define CR1_QUEUE_IC                    GENMASK(1, 0)
/* CR1 cacheability fields don't quite follow the usual TCR-style encoding */
#define CR1_CACHE_NC                    0
#define CR1_CACHE_WB                    1
#define CR1_CACHE_WT                    2

#define ARM_SMMU_CR2                    0x2c
#define CR2_PTM                         (1 << 2)
#define CR2_RECINVSID                   (1 << 1)
#define CR2_E2H                         (1 << 0)

#define ARM_SMMU_GBPA                   0x44
#define GBPA_UPDATE                     (1 << 31)
#define GBPA_ABORT                      (1 << 20)

#define ARM_SMMU_IRQ_CTRL               0x50
#define IRQ_CTRL_EVTQ_IRQEN             (1 << 2)
#define IRQ_CTRL_PRIQ_IRQEN             (1 << 1)
#define IRQ_CTRL_GERROR_IRQEN           (1 << 0)

#define ARM_SMMU_IRQ_CTRLACK            0x54

#define ARM_SMMU_GERROR                 0x60
#define GERROR_SFM_ERR                  (1 << 8)
#define GERROR_MSI_GERROR_ABT_ERR       (1 << 7)
#define GERROR_MSI_PRIQ_ABT_ERR         (1 << 6)
#define GERROR_MSI_EVTQ_ABT_ERR         (1 << 5)
#define GERROR_MSI_CMDQ_ABT_ERR         (1 << 4)
#define GERROR_PRIQ_ABT_ERR             (1 << 3)
#define GERROR_EVTQ_ABT_ERR             (1 << 2)
#define GERROR_CMDQ_ERR                 (1 << 0)
#define GERROR_ERR_MASK                 0xfd

#define ARM_SMMU_GERRORN                0x64

#define ARM_SMMU_GERROR_IRQ_CFG0        0x68
#define ARM_SMMU_GERROR_IRQ_CFG1        0x70
#define ARM_SMMU_GERROR_IRQ_CFG2        0x74

#define ARM_SMMU_STRTAB_BASE            0x80
#define STRTAB_BASE_RA                  (1UL << 62)
#define STRTAB_BASE_ADDR_MASK           GENMASK_ULL(51, 6)

#define ARM_SMMU_STRTAB_BASE_CFG        0x88
#define STRTAB_BASE_CFG_FMT             GENMASK(17, 16)
#define STRTAB_BASE_CFG_FMT_LINEAR      0
#define STRTAB_BASE_CFG_FMT_2LVL        1
#define STRTAB_BASE_CFG_SPLIT           GENMASK(10, 6)
#define STRTAB_BASE_CFG_LOG2SIZE        GENMASK(5, 0)

#define ARM_SMMU_CMDQ_BASE              0x90
#define ARM_SMMU_CMDQ_PROD              0x98
#define ARM_SMMU_CMDQ_CONS              0x9c

#define ARM_SMMU_EVTQ_BASE              0xa0
#define ARM_SMMU_EVTQ_PROD              0x100a8
#define ARM_SMMU_EVTQ_CONS              0x100ac
#define ARM_SMMU_EVTQ_IRQ_CFG0          0xb0
#define ARM_SMMU_EVTQ_IRQ_CFG1          0xb8
#define ARM_SMMU_EVTQ_IRQ_CFG2          0xbc

#define ARM_SMMU_PRIQ_BASE              0xc0
#define ARM_SMMU_PRIQ_PROD              0x100c8
#define ARM_SMMU_PRIQ_CONS              0x100cc
#define ARM_SMMU_PRIQ_IRQ_CFG0          0xd0
#define ARM_SMMU_PRIQ_IRQ_CFG1          0xd8
#define ARM_SMMU_PRIQ_IRQ_CFG2          0xdc

#define ARM_SMMU_REG_SZ                 0xe00

/* Common MSI config fields */
#define MSI_CFG0_ADDR_MASK              GENMASK_ULL(51, 2)
#define MSI_CFG2_SH                     GENMASK(5, 4)
#define MSI_CFG2_MEMATTR                GENMASK(3, 0)

/* Common memory attribute values */
#define ARM_SMMU_SH_NSH                 0
#define ARM_SMMU_SH_OSH                 2
#define ARM_SMMU_SH_ISH                 3
#define ARM_SMMU_MEMATTR_DEVICE_nGnRE   0x1
#define ARM_SMMU_MEMATTR_OIWB           0xf

#define Q_IDX(llq, p)                   ((p) & ((1 << (llq)->max_n_shift) - 1))
#define Q_WRP(llq, p)                   ((p) & (1 << (llq)->max_n_shift))
#define Q_OVERFLOW_FLAG                 (1U << 31)
#define Q_OVF(p)                        ((p) & Q_OVERFLOW_FLAG)
#define Q_ENT(q, p)                     ((q)->base +                    \
                                         Q_IDX(&((q)->llq), p) *        \
                                         (q)->ent_dwords)

#define Q_BASE_RWA                      (1UL << 62)
#define Q_BASE_ADDR_MASK                GENMASK_ULL(51, 5)
#define Q_BASE_LOG2SIZE                 GENMASK(4, 0)

/* Ensure DMA allocations are naturally aligned */
#ifdef CONFIG_CMA_ALIGNMENT
#define Q_MAX_SZ_SHIFT                  (PAGE_SHIFT + CONFIG_CMA_ALIGNMENT)
#else
#define Q_MAX_SZ_SHIFT                  (PAGE_SHIFT + MAX_ORDER - 1)
#endif

/*
 * Stream table.
 *
 * Linear: Enough to cover 1 << IDR1.SIDSIZE entries
 * 2lvl: 128k L1 entries,
 *       256 lazy entries per table (each table covers a PCI bus)
 */
#define STRTAB_L1_SZ_SHIFT              20
#define STRTAB_SPLIT                    8

#define STRTAB_L1_DESC_DWORDS           1
#define STRTAB_L1_DESC_SPAN             GENMASK_ULL(4, 0)
#define STRTAB_L1_DESC_L2PTR_MASK       GENMASK_ULL(51, 6)

#define STRTAB_STE_DWORDS               8
#define STRTAB_STE_0_V                  (1UL << 0)
#define STRTAB_STE_0_CFG                GENMASK_ULL(3, 1)
#define STRTAB_STE_0_CFG_ABORT          0
#define STRTAB_STE_0_CFG_BYPASS         4
#define STRTAB_STE_0_CFG_S1_TRANS       5
#define STRTAB_STE_0_CFG_S2_TRANS       6

#define STRTAB_STE_0_S1FMT              GENMASK_ULL(5, 4)
#define STRTAB_STE_0_S1FMT_LINEAR       0
#define STRTAB_STE_0_S1FMT_64K_L2       2
#define STRTAB_STE_0_S1CTXPTR_MASK      GENMASK_ULL(51, 6)
#define STRTAB_STE_0_S1CDMAX            GENMASK_ULL(63, 59)

#define STRTAB_STE_1_S1DSS              GENMASK_ULL(1, 0)
#define STRTAB_STE_1_S1DSS_TERMINATE    0x0
#define STRTAB_STE_1_S1DSS_BYPASS       0x1
#define STRTAB_STE_1_S1DSS_SSID0        0x2

#define STRTAB_STE_1_S1C_CACHE_NC       0UL
#define STRTAB_STE_1_S1C_CACHE_WBRA     1UL
#define STRTAB_STE_1_S1C_CACHE_WT       2UL
#define STRTAB_STE_1_S1C_CACHE_WB       3UL
#define STRTAB_STE_1_S1CIR              GENMASK_ULL(3, 2)
#define STRTAB_STE_1_S1COR              GENMASK_ULL(5, 4)
#define STRTAB_STE_1_S1CSH              GENMASK_ULL(7, 6)

#define STRTAB_STE_1_S1STALLD           (1UL << 27)

#define STRTAB_STE_1_EATS               GENMASK_ULL(29, 28)
#define STRTAB_STE_1_EATS_ABT           0UL
#define STRTAB_STE_1_EATS_TRANS         1UL
#define STRTAB_STE_1_EATS_S1CHK         2UL

#define STRTAB_STE_1_STRW               GENMASK_ULL(31, 30)
#define STRTAB_STE_1_STRW_NSEL1         0UL
#define STRTAB_STE_1_STRW_EL2           2UL

#define STRTAB_STE_1_SHCFG              GENMASK_ULL(45, 44)
#define STRTAB_STE_1_SHCFG_INCOMING     1UL

#define STRTAB_STE_2_S2VMID             GENMASK_ULL(15, 0)
#define STRTAB_STE_2_VTCR               GENMASK_ULL(50, 32)
#define STRTAB_STE_2_VTCR_S2T0SZ        GENMASK_ULL(5, 0)
#define STRTAB_STE_2_VTCR_S2SL0         GENMASK_ULL(7, 6)
#define STRTAB_STE_2_VTCR_S2IR0         GENMASK_ULL(9, 8)
#define STRTAB_STE_2_VTCR_S2OR0         GENMASK_ULL(11, 10)
#define STRTAB_STE_2_VTCR_S2SH0         GENMASK_ULL(13, 12)
#define STRTAB_STE_2_VTCR_S2TG          GENMASK_ULL(15, 14)
#define STRTAB_STE_2_VTCR_S2PS          GENMASK_ULL(18, 16)
#define STRTAB_STE_2_S2AA64             (1UL << 51)
#define STRTAB_STE_2_S2ENDI             (1UL << 52)
#define STRTAB_STE_2_S2PTW              (1UL << 54)
#define STRTAB_STE_2_S2R                (1UL << 58)

#define STRTAB_STE_3_S2TTB_MASK         GENMASK_ULL(51, 4)

/*
 * Context descriptors.
 *
 * Linear: when less than 1024 SSIDs are supported
 * 2lvl: at most 1024 L1 entries,
 *       1024 lazy entries per table.
 */
#define CTXDESC_SPLIT                   10
#define CTXDESC_L2_ENTRIES              (1 << CTXDESC_SPLIT)

#define CTXDESC_L1_DESC_DWORDS          1
#define CTXDESC_L1_DESC_V               (1UL << 0)
#define CTXDESC_L1_DESC_L2PTR_MASK      GENMASK_ULL(51, 12)

#define CTXDESC_CD_DWORDS               8
#define CTXDESC_CD_0_TCR_T0SZ           GENMASK_ULL(5, 0)
#define CTXDESC_CD_0_TCR_TG0            GENMASK_ULL(7, 6)
#define CTXDESC_CD_0_TCR_IRGN0          GENMASK_ULL(9, 8)
#define CTXDESC_CD_0_TCR_ORGN0          GENMASK_ULL(11, 10)
#define CTXDESC_CD_0_TCR_SH0            GENMASK_ULL(13, 12)
#define CTXDESC_CD_0_TCR_EPD0           (1ULL << 14)
#define CTXDESC_CD_0_TCR_EPD1           (1ULL << 30)

#define CTXDESC_CD_0_ENDI               (1UL << 15)
#define CTXDESC_CD_0_V                  (1UL << 31)

#define CTXDESC_CD_0_TCR_IPS            GENMASK_ULL(34, 32)
#define CTXDESC_CD_0_TCR_TBI0           (1ULL << 38)

#define CTXDESC_CD_0_AA64               (1UL << 41)
#define CTXDESC_CD_0_S                  (1UL << 44)
#define CTXDESC_CD_0_R                  (1UL << 45)
#define CTXDESC_CD_0_A                  (1UL << 46)
#define CTXDESC_CD_0_ASET               (1UL << 47)
#define CTXDESC_CD_0_ASID               GENMASK_ULL(63, 48)

#define CTXDESC_CD_1_TTB0_MASK          GENMASK_ULL(51, 4)

/*
 * When the SMMU only supports linear context descriptor tables, pick a
 * reasonable size limit (64kB).
 */
#define CTXDESC_LINEAR_CDMAX            ilog2(SZ_64K / (CTXDESC_CD_DWORDS << 3))

/* Command queue */
#define CMDQ_ENT_SZ_SHIFT               4
#define CMDQ_ENT_DWORDS                 ((1 << CMDQ_ENT_SZ_SHIFT) >> 3)
#define CMDQ_MAX_SZ_SHIFT               (Q_MAX_SZ_SHIFT - CMDQ_ENT_SZ_SHIFT)

#define CMDQ_CONS_ERR                   GENMASK(30, 24)
#define CMDQ_ERR_CERROR_NONE_IDX        0
#define CMDQ_ERR_CERROR_ILL_IDX         1
#define CMDQ_ERR_CERROR_ABT_IDX         2
#define CMDQ_ERR_CERROR_ATC_INV_IDX     3

#define CMDQ_PROD_OWNED_FLAG            Q_OVERFLOW_FLAG

/*
 * This is used to size the command queue and therefore must be at least
 * BITS_PER_LONG so that the valid_map works correctly (it relies on the
 * total number of queue entries being a multiple of BITS_PER_LONG).
 */
#define CMDQ_BATCH_ENTRIES              BITS_PER_LONG

#define CMDQ_0_OP                       GENMASK_ULL(7, 0)
#define CMDQ_0_SSV                      (1UL << 11)

#define CMDQ_PREFETCH_0_SID             GENMASK_ULL(63, 32)
#define CMDQ_PREFETCH_1_SIZE            GENMASK_ULL(4, 0)
#define CMDQ_PREFETCH_1_ADDR_MASK       GENMASK_ULL(63, 12)

#define CMDQ_CFGI_0_SSID                GENMASK_ULL(31, 12)
#define CMDQ_CFGI_0_SID                 GENMASK_ULL(63, 32)
#define CMDQ_CFGI_1_LEAF                (1UL << 0)
#define CMDQ_CFGI_1_RANGE               GENMASK_ULL(4, 0)

#define CMDQ_TLBI_0_NUM                 GENMASK_ULL(16, 12)
#define CMDQ_TLBI_RANGE_NUM_MAX         31
#define CMDQ_TLBI_0_SCALE               GENMASK_ULL(24, 20)
#define CMDQ_TLBI_0_VMID                GENMASK_ULL(47, 32)
#define CMDQ_TLBI_0_ASID                GENMASK_ULL(63, 48)
#define CMDQ_TLBI_1_LEAF                (1UL << 0)
#define CMDQ_TLBI_1_TTL                 GENMASK_ULL(9, 8)
#define CMDQ_TLBI_1_TG                  GENMASK_ULL(11, 10)
#define CMDQ_TLBI_1_VA_MASK             GENMASK_ULL(63, 12)
#define CMDQ_TLBI_1_IPA_MASK            GENMASK_ULL(51, 12)

#define CMDQ_ATC_0_SSID                 GENMASK_ULL(31, 12)
#define CMDQ_ATC_0_SID                  GENMASK_ULL(63, 32)
#define CMDQ_ATC_0_GLOBAL               (1UL << 9)
#define CMDQ_ATC_1_SIZE                 GENMASK_ULL(5, 0)
#define CMDQ_ATC_1_ADDR_MASK            GENMASK_ULL(63, 12)

#define CMDQ_PRI_0_SSID                 GENMASK_ULL(31, 12)
#define CMDQ_PRI_0_SID                  GENMASK_ULL(63, 32)
#define CMDQ_PRI_1_GRPID                GENMASK_ULL(8, 0)
#define CMDQ_PRI_1_RESP                 GENMASK_ULL(13, 12)

#define CMDQ_SYNC_0_CS                  GENMASK_ULL(13, 12)
#define CMDQ_SYNC_0_CS_NONE             0
#define CMDQ_SYNC_0_CS_IRQ              1
#define CMDQ_SYNC_0_CS_SEV              2
#define CMDQ_SYNC_0_MSH                 GENMASK_ULL(23, 22)
#define CMDQ_SYNC_0_MSIATTR             GENMASK_ULL(27, 24)
#define CMDQ_SYNC_0_MSIDATA             GENMASK_ULL(63, 32)
#define CMDQ_SYNC_1_MSIADDR_MASK        GENMASK_ULL(51, 2)

/* Event queue */
#define EVTQ_ENT_SZ_SHIFT               5
#define EVTQ_ENT_DWORDS                 ((1 << EVTQ_ENT_SZ_SHIFT) >> 3)
#define EVTQ_MAX_SZ_SHIFT               (Q_MAX_SZ_SHIFT - EVTQ_ENT_SZ_SHIFT)

#define EVTQ_0_ID                       GENMASK_ULL(7, 0)

/* PRI queue */
#define PRIQ_ENT_SZ_SHIFT               4
#define PRIQ_ENT_DWORDS                 ((1 << PRIQ_ENT_SZ_SHIFT) >> 3)
#define PRIQ_MAX_SZ_SHIFT               (Q_MAX_SZ_SHIFT - PRIQ_ENT_SZ_SHIFT)

#define PRIQ_0_SID                      GENMASK_ULL(31, 0)
#define PRIQ_0_SSID                     GENMASK_ULL(51, 32)
#define PRIQ_0_PERM_PRIV                (1UL << 58)
#define PRIQ_0_PERM_EXEC                (1UL << 59)
#define PRIQ_0_PERM_READ                (1UL << 60)
#define PRIQ_0_PERM_WRITE               (1UL << 61)
#define PRIQ_0_PRG_LAST                 (1UL << 62)
#define PRIQ_0_SSID_V                   (1UL << 63)

#define PRIQ_1_PRG_IDX                  GENMASK_ULL(8, 0)
#define PRIQ_1_ADDR_MASK                GENMASK_ULL(63, 12)

/* High-level queue structures */
#define ARM_SMMU_POLL_TIMEOUT_US        1000000 /* 1s! */
#define ARM_SMMU_POLL_SPIN_COUNT        10

#define MSI_IOVA_BASE                   0x8000000
#define MSI_IOVA_LENGTH                 0x100000

static bool disable_bypass = 1;
module_param_named(disable_bypass, disable_bypass, bool, S_IRUGO);
MODULE_PARM_DESC(disable_bypass,
        "Disable bypass streams such that incoming transactions from devices that are not attached to an iommu domain will report an abort back to the device and will not be allowed to pass through the SMMU.");

enum pri_resp {
        PRI_RESP_DENY = 0,
        PRI_RESP_FAIL = 1,
        PRI_RESP_SUCC = 2,
};

enum arm_smmu_msi_index {
        EVTQ_MSI_INDEX,
        GERROR_MSI_INDEX,
        PRIQ_MSI_INDEX,
        ARM_SMMU_MAX_MSIS,
};

static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
        [EVTQ_MSI_INDEX] = {
                ARM_SMMU_EVTQ_IRQ_CFG0,
                ARM_SMMU_EVTQ_IRQ_CFG1,
                ARM_SMMU_EVTQ_IRQ_CFG2,
        },
        [GERROR_MSI_INDEX] = {
                ARM_SMMU_GERROR_IRQ_CFG0,
                ARM_SMMU_GERROR_IRQ_CFG1,
                ARM_SMMU_GERROR_IRQ_CFG2,
        },
        [PRIQ_MSI_INDEX] = {
                ARM_SMMU_PRIQ_IRQ_CFG0,
                ARM_SMMU_PRIQ_IRQ_CFG1,
                ARM_SMMU_PRIQ_IRQ_CFG2,
        },
};

struct arm_smmu_cmdq_ent {
        /* Common fields */
        u8                              opcode;
        bool                            substream_valid;

        /* Command-specific fields */
        union {
                #define CMDQ_OP_PREFETCH_CFG    0x1
                struct {
                        u32                     sid;
                        u8                      size;
                        u64                     addr;
                } prefetch;

                #define CMDQ_OP_CFGI_STE        0x3
                #define CMDQ_OP_CFGI_ALL        0x4
                #define CMDQ_OP_CFGI_CD         0x5
                #define CMDQ_OP_CFGI_CD_ALL     0x6
                struct {
                        u32                     sid;
                        u32                     ssid;
                        union {
                                bool            leaf;
                                u8              span;
                        };
                } cfgi;

                #define CMDQ_OP_TLBI_NH_ASID    0x11
                #define CMDQ_OP_TLBI_NH_VA      0x12
                #define CMDQ_OP_TLBI_EL2_ALL    0x20
                #define CMDQ_OP_TLBI_S12_VMALL  0x28
                #define CMDQ_OP_TLBI_S2_IPA     0x2a
                #define CMDQ_OP_TLBI_NSNH_ALL   0x30
                struct {
                        u8                      num;
                        u8                      scale;
                        u16                     asid;
                        u16                     vmid;
                        bool                    leaf;
                        u8                      ttl;
                        u8                      tg;
                        u64                     addr;
                } tlbi;

                #define CMDQ_OP_ATC_INV         0x40
                #define ATC_INV_SIZE_ALL        52
                struct {
                        u32                     sid;
                        u32                     ssid;
                        u64                     addr;
                        u8                      size;
                        bool                    global;
                } atc;

                #define CMDQ_OP_PRI_RESP        0x41
                struct {
                        u32                     sid;
                        u32                     ssid;
                        u16                     grpid;
                        enum pri_resp           resp;
                } pri;

                #define CMDQ_OP_CMD_SYNC        0x46
                struct {
                        u64                     msiaddr;
                } sync;
        };
};

struct arm_smmu_ll_queue {
        union {
                u64                     val;
                struct {
                        u32             prod;
                        u32             cons;
                };
                struct {
                        atomic_t        prod;
                        atomic_t        cons;
                } atomic;
                u8                      __pad[SMP_CACHE_BYTES];
        } ____cacheline_aligned_in_smp;
        u32                             max_n_shift;
};

struct arm_smmu_queue {
        struct arm_smmu_ll_queue        llq;
        int                             irq; /* Wired interrupt */

        __le64                          *base;
        dma_addr_t                      base_dma;
        u64                             q_base;

        size_t                          ent_dwords;

        u32 __iomem                     *prod_reg;
        u32 __iomem                     *cons_reg;
};

struct arm_smmu_queue_poll {
        ktime_t                         timeout;
        unsigned int                    delay;
        unsigned int                    spin_cnt;
        bool                            wfe;
};

struct arm_smmu_cmdq {
        struct arm_smmu_queue           q;
        atomic_long_t                   *valid_map;
        atomic_t                        owner_prod;
        atomic_t                        lock;
};

struct arm_smmu_cmdq_batch {
        u64                             cmds[CMDQ_BATCH_ENTRIES * CMDQ_ENT_DWORDS];
        int                             num;
};

struct arm_smmu_evtq {
        struct arm_smmu_queue           q;
        u32                             max_stalls;
};

struct arm_smmu_priq {
        struct arm_smmu_queue           q;
};

/* High-level stream table and context descriptor structures */
struct arm_smmu_strtab_l1_desc {
        u8                              span;

        __le64                          *l2ptr;
        dma_addr_t                      l2ptr_dma;
};

struct arm_smmu_ctx_desc {
        u16                             asid;
        u64                             ttbr;
        u64                             tcr;
        u64                             mair;
};

struct arm_smmu_l1_ctx_desc {
        __le64                          *l2ptr;
        dma_addr_t                      l2ptr_dma;
};

struct arm_smmu_ctx_desc_cfg {
        __le64                          *cdtab;
        dma_addr_t                      cdtab_dma;
        struct arm_smmu_l1_ctx_desc     *l1_desc;
        unsigned int                    num_l1_ents;
};

struct arm_smmu_s1_cfg {
        struct arm_smmu_ctx_desc_cfg    cdcfg;
        struct arm_smmu_ctx_desc        cd;
        u8                              s1fmt;
        u8                              s1cdmax;
};

struct arm_smmu_s2_cfg {
        u16                             vmid;
        u64                             vttbr;
        u64                             vtcr;
};

struct arm_smmu_strtab_cfg {
        __le64                          *strtab;
        dma_addr_t                      strtab_dma;
        struct arm_smmu_strtab_l1_desc  *l1_desc;
        unsigned int                    num_l1_ents;

        u64                             strtab_base;
        u32                             strtab_base_cfg;
};

/* An SMMUv3 instance */
struct arm_smmu_device {
        struct device                   *dev;
        void __iomem                    *base;
        void __iomem                    *page1;

#define ARM_SMMU_FEAT_2_LVL_STRTAB      (1 << 0)
#define ARM_SMMU_FEAT_2_LVL_CDTAB       (1 << 1)
#define ARM_SMMU_FEAT_TT_LE             (1 << 2)
#define ARM_SMMU_FEAT_TT_BE             (1 << 3)
#define ARM_SMMU_FEAT_PRI               (1 << 4)
#define ARM_SMMU_FEAT_ATS               (1 << 5)
#define ARM_SMMU_FEAT_SEV               (1 << 6)
#define ARM_SMMU_FEAT_MSI               (1 << 7)
#define ARM_SMMU_FEAT_COHERENCY         (1 << 8)
#define ARM_SMMU_FEAT_TRANS_S1          (1 << 9)
#define ARM_SMMU_FEAT_TRANS_S2          (1 << 10)
#define ARM_SMMU_FEAT_STALLS            (1 << 11)
#define ARM_SMMU_FEAT_HYP               (1 << 12)
#define ARM_SMMU_FEAT_STALL_FORCE       (1 << 13)
#define ARM_SMMU_FEAT_VAX               (1 << 14)
#define ARM_SMMU_FEAT_RANGE_INV         (1 << 15)
        u32                             features;

#define ARM_SMMU_OPT_SKIP_PREFETCH      (1 << 0)
#define ARM_SMMU_OPT_PAGE0_REGS_ONLY    (1 << 1)
        u32                             options;

        struct arm_smmu_cmdq            cmdq;
        struct arm_smmu_evtq            evtq;
        struct arm_smmu_priq            priq;

        int                             gerr_irq;
        int                             combined_irq;

        unsigned long                   ias; /* IPA */
        unsigned long                   oas; /* PA */
        unsigned long                   pgsize_bitmap;

#define ARM_SMMU_MAX_ASIDS              (1 << 16)
        unsigned int                    asid_bits;

#define ARM_SMMU_MAX_VMIDS              (1 << 16)
        unsigned int                    vmid_bits;
        DECLARE_BITMAP(vmid_map, ARM_SMMU_MAX_VMIDS);

        unsigned int                    ssid_bits;
        unsigned int                    sid_bits;

        struct arm_smmu_strtab_cfg      strtab_cfg;

        /* IOMMU core code handle */
        struct iommu_device             iommu;
};

/* SMMU private data for each master */
struct arm_smmu_master {
        struct arm_smmu_device          *smmu;
        struct device                   *dev;
        struct arm_smmu_domain          *domain;
        struct list_head                domain_head;
        u32                             *sids;
        unsigned int                    num_sids;
        bool                            ats_enabled;
        unsigned int                    ssid_bits;
};

/* SMMU private data for an IOMMU domain */
enum arm_smmu_domain_stage {
        ARM_SMMU_DOMAIN_S1 = 0,
        ARM_SMMU_DOMAIN_S2,
        ARM_SMMU_DOMAIN_NESTED,
        ARM_SMMU_DOMAIN_BYPASS,
};

struct arm_smmu_domain {
        struct arm_smmu_device          *smmu;
        struct mutex                    init_mutex; /* Protects smmu pointer */

        struct io_pgtable_ops           *pgtbl_ops;
        bool                            non_strict;
        atomic_t                        nr_ats_masters;

        enum arm_smmu_domain_stage      stage;
        union {
                struct arm_smmu_s1_cfg  s1_cfg;
                struct arm_smmu_s2_cfg  s2_cfg;
        };

        struct iommu_domain             domain;

        struct list_head                devices;
        spinlock_t                      devices_lock;
};

struct arm_smmu_option_prop {
        u32 opt;
        const char *prop;
};

static DEFINE_XARRAY_ALLOC1(asid_xa);

static struct arm_smmu_option_prop arm_smmu_options[] = {
        { ARM_SMMU_OPT_SKIP_PREFETCH, "hisilicon,broken-prefetch-cmd" },
        { ARM_SMMU_OPT_PAGE0_REGS_ONLY, "cavium,cn9900-broken-page1-regspace"},
        { 0, NULL},
};

static inline void __iomem *arm_smmu_page1_fixup(unsigned long offset,
                                                 struct arm_smmu_device *smmu)
{
        if (offset > SZ_64K)
                return smmu->page1 + offset - SZ_64K;

        return smmu->base + offset;
}

static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain *dom)
{
        return container_of(dom, struct arm_smmu_domain, domain);
}

static void parse_driver_options(struct arm_smmu_device *smmu)
{
        int i = 0;

        do {
                if (of_property_read_bool(smmu->dev->of_node,
                                                arm_smmu_options[i].prop)) {
                        smmu->options |= arm_smmu_options[i].opt;
                        dev_notice(smmu->dev, "option %s\n",
                                arm_smmu_options[i].prop);
                }
        } while (arm_smmu_options[++i].opt);
}

/* Low-level queue manipulation functions */
static bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
{
        u32 space, prod, cons;

        prod = Q_IDX(q, q->prod);
        cons = Q_IDX(q, q->cons);

        if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
                space = (1 << q->max_n_shift) - (prod - cons);
        else
                space = cons - prod;

        return space >= n;
}

static bool queue_full(struct arm_smmu_ll_queue *q)
{
        return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
               Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
}

static bool queue_empty(struct arm_smmu_ll_queue *q)
{
        return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
               Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
}

static bool queue_consumed(struct arm_smmu_ll_queue *q, u32 prod)
{
        return ((Q_WRP(q, q->cons) == Q_WRP(q, prod)) &&
                (Q_IDX(q, q->cons) > Q_IDX(q, prod))) ||
               ((Q_WRP(q, q->cons) != Q_WRP(q, prod)) &&
                (Q_IDX(q, q->cons) <= Q_IDX(q, prod)));
}

static void queue_sync_cons_out(struct arm_smmu_queue *q)
{
        /*
         * Ensure that all CPU accesses (reads and writes) to the queue
         * are complete before we update the cons pointer.
         */
        mb();
        writel_relaxed(q->llq.cons, q->cons_reg);
}

static void queue_inc_cons(struct arm_smmu_ll_queue *q)
{
        u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
        q->cons = Q_OVF(q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
}

static int queue_sync_prod_in(struct arm_smmu_queue *q)
{
        int ret = 0;
        u32 prod = readl_relaxed(q->prod_reg);

        if (Q_OVF(prod) != Q_OVF(q->llq.prod))
                ret = -EOVERFLOW;

        q->llq.prod = prod;
        return ret;
}

static u32 queue_inc_prod_n(struct arm_smmu_ll_queue *q, int n)
{
        u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + n;
        return Q_OVF(q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
}

static void queue_poll_init(struct arm_smmu_device *smmu,
                            struct arm_smmu_queue_poll *qp)
{
        qp->delay = 1;
        qp->spin_cnt = 0;
        qp->wfe = !!(smmu->features & ARM_SMMU_FEAT_SEV);
        qp->timeout = ktime_add_us(ktime_get(), ARM_SMMU_POLL_TIMEOUT_US);
}

static int queue_poll(struct arm_smmu_queue_poll *qp)
{
        if (ktime_compare(ktime_get(), qp->timeout) > 0)
                return -ETIMEDOUT;

        if (qp->wfe) {
                wfe();
        } else if (++qp->spin_cnt < ARM_SMMU_POLL_SPIN_COUNT) {
                cpu_relax();
        } else {
                udelay(qp->delay);
                qp->delay *= 2;
                qp->spin_cnt = 0;
        }

        return 0;
}

static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
{
        int i;

        for (i = 0; i < n_dwords; ++i)
                *dst++ = cpu_to_le64(*src++);
}

static void queue_read(__le64 *dst, u64 *src, size_t n_dwords)
{
        int i;

        for (i = 0; i < n_dwords; ++i)
                *dst++ = le64_to_cpu(*src++);
}

static int queue_remove_raw(struct arm_smmu_queue *q, u64 *ent)
{
        if (queue_empty(&q->llq))
                return -EAGAIN;

        queue_read(ent, Q_ENT(q, q->llq.cons), q->ent_dwords);
        queue_inc_cons(&q->llq);
        queue_sync_cons_out(q);
        return 0;
}

/* High-level queue accessors */
static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
{
        memset(cmd, 0, 1 << CMDQ_ENT_SZ_SHIFT);
        cmd[0] |= FIELD_PREP(CMDQ_0_OP, ent->opcode);

        switch (ent->opcode) {
        case CMDQ_OP_TLBI_EL2_ALL:
        case CMDQ_OP_TLBI_NSNH_ALL:
                break;
        case CMDQ_OP_PREFETCH_CFG:
                cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid);
                cmd[1] |= FIELD_PREP(CMDQ_PREFETCH_1_SIZE, ent->prefetch.size);
                cmd[1] |= ent->prefetch.addr & CMDQ_PREFETCH_1_ADDR_MASK;
                break;
        case CMDQ_OP_CFGI_CD:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SSID, ent->cfgi.ssid);
                fallthrough;
        case CMDQ_OP_CFGI_STE:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
                cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_LEAF, ent->cfgi.leaf);
                break;
        case CMDQ_OP_CFGI_CD_ALL:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
                break;
        case CMDQ_OP_CFGI_ALL:
                /* Cover the entire SID range */
                cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31);
                break;
        case CMDQ_OP_TLBI_NH_VA:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_VA_MASK;
                break;
        case CMDQ_OP_TLBI_S2_IPA:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_IPA_MASK;
                break;
        case CMDQ_OP_TLBI_NH_ASID:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
                fallthrough;
        case CMDQ_OP_TLBI_S12_VMALL:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                break;
        case CMDQ_OP_ATC_INV:
                cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_GLOBAL, ent->atc.global);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SSID, ent->atc.ssid);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SID, ent->atc.sid);
                cmd[1] |= FIELD_PREP(CMDQ_ATC_1_SIZE, ent->atc.size);
                cmd[1] |= ent->atc.addr & CMDQ_ATC_1_ADDR_MASK;
                break;
        case CMDQ_OP_PRI_RESP:
                cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
                cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SSID, ent->pri.ssid);
                cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SID, ent->pri.sid);
                cmd[1] |= FIELD_PREP(CMDQ_PRI_1_GRPID, ent->pri.grpid);
                switch (ent->pri.resp) {
                case PRI_RESP_DENY:
                case PRI_RESP_FAIL:
                case PRI_RESP_SUCC:
                        break;
                default:
                        return -EINVAL;
                }
                cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
                break;
        case CMDQ_OP_CMD_SYNC:
                if (ent->sync.msiaddr) {
                        cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_IRQ);
                        cmd[1] |= ent->sync.msiaddr & CMDQ_SYNC_1_MSIADDR_MASK;
                } else {
                        cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
                }
                cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSH, ARM_SMMU_SH_ISH);
                cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSIATTR, ARM_SMMU_MEMATTR_OIWB);
                break;
        default:
                return -ENOENT;
        }

        return 0;
}

static void arm_smmu_cmdq_build_sync_cmd(u64 *cmd, struct arm_smmu_device *smmu,
                                         u32 prod)
{
        struct arm_smmu_queue *q = &smmu->cmdq.q;
        struct arm_smmu_cmdq_ent ent = {
                .opcode = CMDQ_OP_CMD_SYNC,
        };

        /*
         * Beware that Hi16xx adds an extra 32 bits of goodness to its MSI
         * payload, so the write will zero the entire command on that platform.
         */
        if (smmu->features & ARM_SMMU_FEAT_MSI &&
            smmu->features & ARM_SMMU_FEAT_COHERENCY) {
                ent.sync.msiaddr = q->base_dma + Q_IDX(&q->llq, prod) *
                                   q->ent_dwords * 8;
        }

        arm_smmu_cmdq_build_cmd(cmd, &ent);
}

static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
{
        static const char *cerror_str[] = {
                [CMDQ_ERR_CERROR_NONE_IDX]      = "No error",
                [CMDQ_ERR_CERROR_ILL_IDX]       = "Illegal command",
                [CMDQ_ERR_CERROR_ABT_IDX]       = "Abort on command fetch",
                [CMDQ_ERR_CERROR_ATC_INV_IDX]   = "ATC invalidate timeout",
        };

        int i;
        u64 cmd[CMDQ_ENT_DWORDS];
        struct arm_smmu_queue *q = &smmu->cmdq.q;
        u32 cons = readl_relaxed(q->cons_reg);
        u32 idx = FIELD_GET(CMDQ_CONS_ERR, cons);
        struct arm_smmu_cmdq_ent cmd_sync = {
                .opcode = CMDQ_OP_CMD_SYNC,
        };

        dev_err(smmu->dev, "CMDQ error (cons 0x%08x): %s\n", cons,
                idx < ARRAY_SIZE(cerror_str) ?  cerror_str[idx] : "Unknown");

        switch (idx) {
        case CMDQ_ERR_CERROR_ABT_IDX:
                dev_err(smmu->dev, "retrying command fetch\n");
        case CMDQ_ERR_CERROR_NONE_IDX:
                return;
        case CMDQ_ERR_CERROR_ATC_INV_IDX:
                /*
                 * ATC Invalidation Completion timeout. CONS is still pointing
                 * at the CMD_SYNC. Attempt to complete other pending commands
                 * by repeating the CMD_SYNC, though we might well end up back
                 * here since the ATC invalidation may still be pending.
                 */
                return;
        case CMDQ_ERR_CERROR_ILL_IDX:
        default:
                break;
        }

        /*
         * We may have concurrent producers, so we need to be careful
         * not to touch any of the shadow cmdq state.
         */
        queue_read(cmd, Q_ENT(q, cons), q->ent_dwords);
        dev_err(smmu->dev, "skipping command in error state:\n");
        for (i = 0; i < ARRAY_SIZE(cmd); ++i)
                dev_err(smmu->dev, "\t0x%016llx\n", (unsigned long long)cmd[i]);

        /* Convert the erroneous command into a CMD_SYNC */
        if (arm_smmu_cmdq_build_cmd(cmd, &cmd_sync)) {
                dev_err(smmu->dev, "failed to convert to CMD_SYNC\n");
                return;
        }

        queue_write(Q_ENT(q, cons), cmd, q->ent_dwords);
}

/*
 * Command queue locking.
 * This is a form of bastardised rwlock with the following major changes:
 *
 * - The only LOCK routines are exclusive_trylock() and shared_lock().
 *   Neither have barrier semantics, and instead provide only a control
 *   dependency.
 *
 * - The UNLOCK routines are supplemented with shared_tryunlock(), which
 *   fails if the caller appears to be the last lock holder (yes, this is
 *   racy). All successful UNLOCK routines have RELEASE semantics.
 */
static void arm_smmu_cmdq_shared_lock(struct arm_smmu_cmdq *cmdq)
{
        int val;

        /*
         * We can try to avoid the cmpxchg() loop by simply incrementing the
         * lock counter. When held in exclusive state, the lock counter is set
         * to INT_MIN so these increments won't hurt as the value will remain
         * negative.
         */
        if (atomic_fetch_inc_relaxed(&cmdq->lock) >= 0)
                return;

        do {
                val = atomic_cond_read_relaxed(&cmdq->lock, VAL >= 0);
        } while (atomic_cmpxchg_relaxed(&cmdq->lock, val, val + 1) != val);
}

static void arm_smmu_cmdq_shared_unlock(struct arm_smmu_cmdq *cmdq)
{
        (void)atomic_dec_return_release(&cmdq->lock);
}

static bool arm_smmu_cmdq_shared_tryunlock(struct arm_smmu_cmdq *cmdq)
{
        if (atomic_read(&cmdq->lock) == 1)
                return false;

        arm_smmu_cmdq_shared_unlock(cmdq);
        return true;
}

#define arm_smmu_cmdq_exclusive_trylock_irqsave(cmdq, flags)            \
({                                                                      \
        bool __ret;                                                     \
        local_irq_save(flags);                                          \
        __ret = !atomic_cmpxchg_relaxed(&cmdq->lock, 0, INT_MIN);       \
        if (!__ret)                                                     \
                local_irq_restore(flags);                               \
        __ret;                                                          \
})

#define arm_smmu_cmdq_exclusive_unlock_irqrestore(cmdq, flags)          \
({                                                                      \
        atomic_set_release(&cmdq->lock, 0);                             \
        local_irq_restore(flags);                                       \
})


/*
 * Command queue insertion.
 * This is made fiddly by our attempts to achieve some sort of scalability
 * since there is one queue shared amongst all of the CPUs in the system.  If
 * you like mixed-size concurrency, dependency ordering and relaxed atomics,
 * then you'll *love* this monstrosity.
 *
 * The basic idea is to split the queue up into ranges of commands that are
 * owned by a given CPU; the owner may not have written all of the commands
 * itself, but is responsible for advancing the hardware prod pointer when
 * the time comes. The algorithm is roughly:
 *
 *      1. Allocate some space in the queue. At this point we also discover
 *         whether the head of the queue is currently owned by another CPU,
 *         or whether we are the owner.
 *
 *      2. Write our commands into our allocated slots in the queue.
 *
 *      3. Mark our slots as valid in arm_smmu_cmdq.valid_map.
 *
 *      4. If we are an owner:
 *              a. Wait for the previous owner to finish.
 *              b. Mark the queue head as unowned, which tells us the range
 *                 that we are responsible for publishing.
 *              c. Wait for all commands in our owned range to become valid.
 *              d. Advance the hardware prod pointer.
 *              e. Tell the next owner we've finished.
 *
 *      5. If we are inserting a CMD_SYNC (we may or may not have been an
 *         owner), then we need to stick around until it has completed:
 *              a. If we have MSIs, the SMMU can write back into the CMD_SYNC
 *                 to clear the first 4 bytes.
 *              b. Otherwise, we spin waiting for the hardware cons pointer to
 *                 advance past our command.
 *
 * The devil is in the details, particularly the use of locking for handling
 * SYNC completion and freeing up space in the queue before we think that it is
 * full.
 */
static void __arm_smmu_cmdq_poll_set_valid_map(struct arm_smmu_cmdq *cmdq,
                                               u32 sprod, u32 eprod, bool set)
{
        u32 swidx, sbidx, ewidx, ebidx;
        struct arm_smmu_ll_queue llq = {
                .max_n_shift    = cmdq->q.llq.max_n_shift,
                .prod           = sprod,
        };

        ewidx = BIT_WORD(Q_IDX(&llq, eprod));
        ebidx = Q_IDX(&llq, eprod) % BITS_PER_LONG;

        while (llq.prod != eprod) {
                unsigned long mask;
                atomic_long_t *ptr;
                u32 limit = BITS_PER_LONG;

                swidx = BIT_WORD(Q_IDX(&llq, llq.prod));
                sbidx = Q_IDX(&llq, llq.prod) % BITS_PER_LONG;

                ptr = &cmdq->valid_map[swidx];

                if ((swidx == ewidx) && (sbidx < ebidx))
                        limit = ebidx;

                mask = GENMASK(limit - 1, sbidx);

                /*
                 * The valid bit is the inverse of the wrap bit. This means
                 * that a zero-initialised queue is invalid and, after marking
                 * all entries as valid, they become invalid again when we
                 * wrap.
                 */
                if (set) {
                        atomic_long_xor(mask, ptr);
                } else { /* Poll */
                        unsigned long valid;

                        valid = (ULONG_MAX + !!Q_WRP(&llq, llq.prod)) & mask;
                        atomic_long_cond_read_relaxed(ptr, (VAL & mask) == valid);
                }

                llq.prod = queue_inc_prod_n(&llq, limit - sbidx);
        }
}

/* Mark all entries in the range [sprod, eprod) as valid */
static void arm_smmu_cmdq_set_valid_map(struct arm_smmu_cmdq *cmdq,
                                        u32 sprod, u32 eprod)
{
        __arm_smmu_cmdq_poll_set_valid_map(cmdq, sprod, eprod, true);
}

/* Wait for all entries in the range [sprod, eprod) to become valid */
static void arm_smmu_cmdq_poll_valid_map(struct arm_smmu_cmdq *cmdq,
                                         u32 sprod, u32 eprod)
{
        __arm_smmu_cmdq_poll_set_valid_map(cmdq, sprod, eprod, false);
}

/* Wait for the command queue to become non-full */
static int arm_smmu_cmdq_poll_until_not_full(struct arm_smmu_device *smmu,
                                             struct arm_smmu_ll_queue *llq)
{
        unsigned long flags;
        struct arm_smmu_queue_poll qp;
        struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
        int ret = 0;

        /*
         * Try to update our copy of cons by grabbing exclusive cmdq access. If
         * that fails, spin until somebody else updates it for us.
         */
        if (arm_smmu_cmdq_exclusive_trylock_irqsave(cmdq, flags)) {
                WRITE_ONCE(cmdq->q.llq.cons, readl_relaxed(cmdq->q.cons_reg));
                arm_smmu_cmdq_exclusive_unlock_irqrestore(cmdq, flags);
                llq->val = READ_ONCE(cmdq->q.llq.val);
                return 0;
        }

        queue_poll_init(smmu, &qp);
        do {
                llq->val = READ_ONCE(smmu->cmdq.q.llq.val);
                if (!queue_full(llq))
                        break;

                ret = queue_poll(&qp);
        } while (!ret);

        return ret;
}

/*
 * Wait until the SMMU signals a CMD_SYNC completion MSI.
 * Must be called with the cmdq lock held in some capacity.
 */
static int __arm_smmu_cmdq_poll_until_msi(struct arm_smmu_device *smmu,
                                          struct arm_smmu_ll_queue *llq)
{
        int ret = 0;
        struct arm_smmu_queue_poll qp;
        struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
        u32 *cmd = (u32 *)(Q_ENT(&cmdq->q, llq->prod));

        queue_poll_init(smmu, &qp);

        /*
         * The MSI won't generate an event, since it's being written back
         * into the command queue.
         */
        qp.wfe = false;
        smp_cond_load_relaxed(cmd, !VAL || (ret = queue_poll(&qp)));
        llq->cons = ret ? llq->prod : queue_inc_prod_n(llq, 1);
        return ret;
}

/*
 * Wait until the SMMU cons index passes llq->prod.
 * Must be called with the cmdq lock held in some capacity.
 */
static int __arm_smmu_cmdq_poll_until_consumed(struct arm_smmu_device *smmu,
                                               struct arm_smmu_ll_queue *llq)
{
        struct arm_smmu_queue_poll qp;
        struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
        u32 prod = llq->prod;
        int ret = 0;

        queue_poll_init(smmu, &qp);
        llq->val = READ_ONCE(smmu->cmdq.q.llq.val);
        do {
                if (queue_consumed(llq, prod))
                        break;

                ret = queue_poll(&qp);

                /*
                 * This needs to be a readl() so that our subsequent call
                 * to arm_smmu_cmdq_shared_tryunlock() can fail accurately.
                 *
                 * Specifically, we need to ensure that we observe all
                 * shared_lock()s by other CMD_SYNCs that share our owner,
                 * so that a failing call to tryunlock() means that we're
                 * the last one out and therefore we can safely advance
                 * cmdq->q.llq.cons. Roughly speaking:
                 *
                 * CPU 0                CPU1                    CPU2 (us)
                 *
                 * if (sync)
                 *      shared_lock();
                 *
                 * dma_wmb();
                 * set_valid_map();
                 *
                 *                      if (owner) {
                 *                              poll_valid_map();
                 *                              <control dependency>
                 *                              writel(prod_reg);
                 *
                 *                                              readl(cons_reg);
                 *                                              tryunlock();
                 *
                 * Requires us to see CPU 0's shared_lock() acquisition.
                 */
                llq->cons = readl(cmdq->q.cons_reg);
        } while (!ret);

        return ret;
}

static int arm_smmu_cmdq_poll_until_sync(struct arm_smmu_device *smmu,
                                         struct arm_smmu_ll_queue *llq)
{
        if (smmu->features & ARM_SMMU_FEAT_MSI &&
            smmu->features & ARM_SMMU_FEAT_COHERENCY)
                return __arm_smmu_cmdq_poll_until_msi(smmu, llq);

        return __arm_smmu_cmdq_poll_until_consumed(smmu, llq);
}

static void arm_smmu_cmdq_write_entries(struct arm_smmu_cmdq *cmdq, u64 *cmds,
                                        u32 prod, int n)
{
        int i;
        struct arm_smmu_ll_queue llq = {
                .max_n_shift    = cmdq->q.llq.max_n_shift,
                .prod           = prod,
        };

        for (i = 0; i < n; ++i) {
                u64 *cmd = &cmds[i * CMDQ_ENT_DWORDS];

                prod = queue_inc_prod_n(&llq, i);
                queue_write(Q_ENT(&cmdq->q, prod), cmd, CMDQ_ENT_DWORDS);
        }
}

/*
 * This is the actual insertion function, and provides the following
 * ordering guarantees to callers:
 *
 * - There is a dma_wmb() before publishing any commands to the queue.
 *   This can be relied upon to order prior writes to data structures
 *   in memory (such as a CD or an STE) before the command.
 *
 * - On completion of a CMD_SYNC, there is a control dependency.
 *   This can be relied upon to order subsequent writes to memory (e.g.
 *   freeing an IOVA) after completion of the CMD_SYNC.
 *
 * - Command insertion is totally ordered, so if two CPUs each race to
 *   insert their own list of commands then all of the commands from one
 *   CPU will appear before any of the commands from the other CPU.
 */
static int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
                                       u64 *cmds, int n, bool sync)
{
        u64 cmd_sync[CMDQ_ENT_DWORDS];
        u32 prod;
        unsigned long flags;
        bool owner;
        struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
        struct arm_smmu_ll_queue llq = {
                .max_n_shift = cmdq->q.llq.max_n_shift,
        }, head = llq;
        int ret = 0;

        /* 1. Allocate some space in the queue */
        local_irq_save(flags);
        llq.val = READ_ONCE(cmdq->q.llq.val);
        do {
                u64 old;

                while (!queue_has_space(&llq, n + sync)) {
                        local_irq_restore(flags);
                        if (arm_smmu_cmdq_poll_until_not_full(smmu, &llq))
                                dev_err_ratelimited(smmu->dev, "CMDQ timeout\n");
                        local_irq_save(flags);
                }

                head.cons = llq.cons;
                head.prod = queue_inc_prod_n(&llq, n + sync) |
                                             CMDQ_PROD_OWNED_FLAG;

                old = cmpxchg_relaxed(&cmdq->q.llq.val, llq.val, head.val);
                if (old == llq.val)
                        break;

                llq.val = old;
        } while (1);
        owner = !(llq.prod & CMDQ_PROD_OWNED_FLAG);
        head.prod &= ~CMDQ_PROD_OWNED_FLAG;
        llq.prod &= ~CMDQ_PROD_OWNED_FLAG;

        /*
         * 2. Write our commands into the queue
         * Dependency ordering from the cmpxchg() loop above.
         */
        arm_smmu_cmdq_write_entries(cmdq, cmds, llq.prod, n);
        if (sync) {
                prod = queue_inc_prod_n(&llq, n);
                arm_smmu_cmdq_build_sync_cmd(cmd_sync, smmu, prod);
                queue_write(Q_ENT(&cmdq->q, prod), cmd_sync, CMDQ_ENT_DWORDS);

                /*
                 * In order to determine completion of our CMD_SYNC, we must
                 * ensure that the queue can't wrap twice without us noticing.
                 * We achieve that by taking the cmdq lock as shared before
                 * marking our slot as valid.
                 */
                arm_smmu_cmdq_shared_lock(cmdq);
        }

        /* 3. Mark our slots as valid, ensuring commands are visible first */
        dma_wmb();
        arm_smmu_cmdq_set_valid_map(cmdq, llq.prod, head.prod);

        /* 4. If we are the owner, take control of the SMMU hardware */
        if (owner) {
                /* a. Wait for previous owner to finish */
                atomic_cond_read_relaxed(&cmdq->owner_prod, VAL == llq.prod);

                /* b. Stop gathering work by clearing the owned flag */
                prod = atomic_fetch_andnot_relaxed(CMDQ_PROD_OWNED_FLAG,
                                                   &cmdq->q.llq.atomic.prod);
                prod &= ~CMDQ_PROD_OWNED_FLAG;

                /*
                 * c. Wait for any gathered work to be written to the queue.
                 * Note that we read our own entries so that we have the control
                 * dependency required by (d).
                 */
                arm_smmu_cmdq_poll_valid_map(cmdq, llq.prod, prod);

                /*
                 * d. Advance the hardware prod pointer
                 * Control dependency ordering from the entries becoming valid.
                 */
                writel_relaxed(prod, cmdq->q.prod_reg);

                /*
                 * e. Tell the next owner we're done
                 * Make sure we've updated the hardware first, so that we don't
                 * race to update prod and potentially move it backwards.
                 */
                atomic_set_release(&cmdq->owner_prod, prod);
        }

        /* 5. If we are inserting a CMD_SYNC, we must wait for it to complete */
        if (sync) {
                llq.prod = queue_inc_prod_n(&llq, n);
                ret = arm_smmu_cmdq_poll_until_sync(smmu, &llq);
                if (ret) {
                        dev_err_ratelimited(smmu->dev,
                                            "CMD_SYNC timeout at 0x%08x [hwprod 0x%08x, hwcons 0x%08x]\n",
                                            llq.prod,
                                            readl_relaxed(cmdq->q.prod_reg),
                                            readl_relaxed(cmdq->q.cons_reg));
                }

                /*
                 * Try to unlock the cmdq lock. This will fail if we're the last
                 * reader, in which case we can safely update cmdq->q.llq.cons
                 */
                if (!arm_smmu_cmdq_shared_tryunlock(cmdq)) {
                        WRITE_ONCE(cmdq->q.llq.cons, llq.cons);
                        arm_smmu_cmdq_shared_unlock(cmdq);
                }
        }

        local_irq_restore(flags);
        return ret;
}

static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
                                   struct arm_smmu_cmdq_ent *ent)
{
        u64 cmd[CMDQ_ENT_DWORDS];

        if (arm_smmu_cmdq_build_cmd(cmd, ent)) {
                dev_warn(smmu->dev, "ignoring unknown CMDQ opcode 0x%x\n",
                         ent->opcode);
                return -EINVAL;
        }

        return arm_smmu_cmdq_issue_cmdlist(smmu, cmd, 1, false);
}

static int arm_smmu_cmdq_issue_sync(struct arm_smmu_device *smmu)
{
        return arm_smmu_cmdq_issue_cmdlist(smmu, NULL, 0, true);
}

static void arm_smmu_cmdq_batch_add(struct arm_smmu_device *smmu,
                                    struct arm_smmu_cmdq_batch *cmds,
                                    struct arm_smmu_cmdq_ent *cmd)
{
        if (cmds->num == CMDQ_BATCH_ENTRIES) {
                arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, false);
                cmds->num = 0;
        }
        arm_smmu_cmdq_build_cmd(&cmds->cmds[cmds->num * CMDQ_ENT_DWORDS], cmd);
        cmds->num++;
}

static int arm_smmu_cmdq_batch_submit(struct arm_smmu_device *smmu,
                                      struct arm_smmu_cmdq_batch *cmds)
{
        return arm_smmu_cmdq_issue_cmdlist(smmu, cmds->cmds, cmds->num, true);
}

/* Context descriptor manipulation functions */
static void arm_smmu_sync_cd(struct arm_smmu_domain *smmu_domain,
                             int ssid, bool leaf)
{
        size_t i;
        unsigned long flags;
        struct arm_smmu_master *master;
        struct arm_smmu_cmdq_batch cmds = {};
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_cmdq_ent cmd = {
                .opcode = CMDQ_OP_CFGI_CD,
                .cfgi   = {
                        .ssid   = ssid,
                        .leaf   = leaf,
                },
        };

        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
        list_for_each_entry(master, &smmu_domain->devices, domain_head) {
                for (i = 0; i < master->num_sids; i++) {
                        cmd.cfgi.sid = master->sids[i];
                        arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
                }
        }
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

        arm_smmu_cmdq_batch_submit(smmu, &cmds);
}

static int arm_smmu_alloc_cd_leaf_table(struct arm_smmu_device *smmu,
                                        struct arm_smmu_l1_ctx_desc *l1_desc)
{
        size_t size = CTXDESC_L2_ENTRIES * (CTXDESC_CD_DWORDS << 3);

        l1_desc->l2ptr = dmam_alloc_coherent(smmu->dev, size,
                                             &l1_desc->l2ptr_dma, GFP_KERNEL);
        if (!l1_desc->l2ptr) {
                dev_warn(smmu->dev,
                         "failed to allocate context descriptor table\n");
                return -ENOMEM;
        }
        return 0;
}

static void arm_smmu_write_cd_l1_desc(__le64 *dst,
                                      struct arm_smmu_l1_ctx_desc *l1_desc)
{
        u64 val = (l1_desc->l2ptr_dma & CTXDESC_L1_DESC_L2PTR_MASK) |
                  CTXDESC_L1_DESC_V;

        /* See comment in arm_smmu_write_ctx_desc() */
        WRITE_ONCE(*dst, cpu_to_le64(val));
}

static __le64 *arm_smmu_get_cd_ptr(struct arm_smmu_domain *smmu_domain,
                                   u32 ssid)
{
        __le64 *l1ptr;
        unsigned int idx;
        struct arm_smmu_l1_ctx_desc *l1_desc;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->s1_cfg.cdcfg;

        if (smmu_domain->s1_cfg.s1fmt == STRTAB_STE_0_S1FMT_LINEAR)
                return cdcfg->cdtab + ssid * CTXDESC_CD_DWORDS;

        idx = ssid >> CTXDESC_SPLIT;
        l1_desc = &cdcfg->l1_desc[idx];
        if (!l1_desc->l2ptr) {
                if (arm_smmu_alloc_cd_leaf_table(smmu, l1_desc))
                        return NULL;

                l1ptr = cdcfg->cdtab + idx * CTXDESC_L1_DESC_DWORDS;
                arm_smmu_write_cd_l1_desc(l1ptr, l1_desc);
                /* An invalid L1CD can be cached */
                arm_smmu_sync_cd(smmu_domain, ssid, false);
        }
        idx = ssid & (CTXDESC_L2_ENTRIES - 1);
        return l1_desc->l2ptr + idx * CTXDESC_CD_DWORDS;
}

static int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain,
                                   int ssid, struct arm_smmu_ctx_desc *cd)
{
        /*
         * This function handles the following cases:
         *
         * (1) Install primary CD, for normal DMA traffic (SSID = 0).
         * (2) Install a secondary CD, for SID+SSID traffic.
         * (3) Update ASID of a CD. Atomically write the first 64 bits of the
         *     CD, then invalidate the old entry and mappings.
         * (4) Remove a secondary CD.
         */
        u64 val;
        bool cd_live;
        __le64 *cdptr;
        struct arm_smmu_device *smmu = smmu_domain->smmu;

        if (WARN_ON(ssid >= (1 << smmu_domain->s1_cfg.s1cdmax)))
                return -E2BIG;

        cdptr = arm_smmu_get_cd_ptr(smmu_domain, ssid);
        if (!cdptr)
                return -ENOMEM;

        val = le64_to_cpu(cdptr[0]);
        cd_live = !!(val & CTXDESC_CD_0_V);

        if (!cd) { /* (4) */
                val = 0;
        } else if (cd_live) { /* (3) */
                val &= ~CTXDESC_CD_0_ASID;
                val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid);
                /*
                 * Until CD+TLB invalidation, both ASIDs may be used for tagging
                 * this substream's traffic
                 */
        } else { /* (1) and (2) */
                cdptr[1] = cpu_to_le64(cd->ttbr & CTXDESC_CD_1_TTB0_MASK);
                cdptr[2] = 0;
                cdptr[3] = cpu_to_le64(cd->mair);

                /*
                 * STE is live, and the SMMU might read dwords of this CD in any
                 * order. Ensure that it observes valid values before reading
                 * V=1.
                 */
                arm_smmu_sync_cd(smmu_domain, ssid, true);

                val = cd->tcr |
#ifdef __BIG_ENDIAN
                        CTXDESC_CD_0_ENDI |
#endif
                        CTXDESC_CD_0_R | CTXDESC_CD_0_A | CTXDESC_CD_0_ASET |
                        CTXDESC_CD_0_AA64 |
                        FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
                        CTXDESC_CD_0_V;

                /* STALL_MODEL==0b10 && CD.S==0 is ILLEGAL */
                if (smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
                        val |= CTXDESC_CD_0_S;
        }

        /*
         * The SMMU accesses 64-bit values atomically. See IHI0070Ca 3.21.3
         * "Configuration structures and configuration invalidation completion"
         *
         *   The size of single-copy atomic reads made by the SMMU is
         *   IMPLEMENTATION DEFINED but must be at least 64 bits. Any single
         *   field within an aligned 64-bit span of a structure can be altered
         *   without first making the structure invalid.
         */
        WRITE_ONCE(cdptr[0], cpu_to_le64(val));
        arm_smmu_sync_cd(smmu_domain, ssid, true);
        return 0;
}

static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain)
{
        int ret;
        size_t l1size;
        size_t max_contexts;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
        struct arm_smmu_ctx_desc_cfg *cdcfg = &cfg->cdcfg;

        max_contexts = 1 << cfg->s1cdmax;

        if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB) ||
            max_contexts <= CTXDESC_L2_ENTRIES) {
                cfg->s1fmt = STRTAB_STE_0_S1FMT_LINEAR;
                cdcfg->num_l1_ents = max_contexts;

                l1size = max_contexts * (CTXDESC_CD_DWORDS << 3);
        } else {
                cfg->s1fmt = STRTAB_STE_0_S1FMT_64K_L2;
                cdcfg->num_l1_ents = DIV_ROUND_UP(max_contexts,
                                                  CTXDESC_L2_ENTRIES);

                cdcfg->l1_desc = devm_kcalloc(smmu->dev, cdcfg->num_l1_ents,
                                              sizeof(*cdcfg->l1_desc),
                                              GFP_KERNEL);
                if (!cdcfg->l1_desc)
                        return -ENOMEM;

                l1size = cdcfg->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
        }

        cdcfg->cdtab = dmam_alloc_coherent(smmu->dev, l1size, &cdcfg->cdtab_dma,
                                           GFP_KERNEL);
        if (!cdcfg->cdtab) {
                dev_warn(smmu->dev, "failed to allocate context descriptor\n");
                ret = -ENOMEM;
                goto err_free_l1;
        }

        return 0;

err_free_l1:
        if (cdcfg->l1_desc) {
                devm_kfree(smmu->dev, cdcfg->l1_desc);
                cdcfg->l1_desc = NULL;
        }
        return ret;
}

static void arm_smmu_free_cd_tables(struct arm_smmu_domain *smmu_domain)
{
        int i;
        size_t size, l1size;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->s1_cfg.cdcfg;

        if (cdcfg->l1_desc) {
                size = CTXDESC_L2_ENTRIES * (CTXDESC_CD_DWORDS << 3);

                for (i = 0; i < cdcfg->num_l1_ents; i++) {
                        if (!cdcfg->l1_desc[i].l2ptr)
                                continue;

                        dmam_free_coherent(smmu->dev, size,
                                           cdcfg->l1_desc[i].l2ptr,
                                           cdcfg->l1_desc[i].l2ptr_dma);
                }
                devm_kfree(smmu->dev, cdcfg->l1_desc);
                cdcfg->l1_desc = NULL;

                l1size = cdcfg->num_l1_ents * (CTXDESC_L1_DESC_DWORDS << 3);
        } else {
                l1size = cdcfg->num_l1_ents * (CTXDESC_CD_DWORDS << 3);
        }

        dmam_free_coherent(smmu->dev, l1size, cdcfg->cdtab, cdcfg->cdtab_dma);
        cdcfg->cdtab_dma = 0;
        cdcfg->cdtab = NULL;
}

static void arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd)
{
        if (!cd->asid)
                return;

        xa_erase(&asid_xa, cd->asid);
}

/* Stream table manipulation functions */
static void
arm_smmu_write_strtab_l1_desc(__le64 *dst, struct arm_smmu_strtab_l1_desc *desc)
{
        u64 val = 0;

        val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, desc->span);
        val |= desc->l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK;

        /* See comment in arm_smmu_write_ctx_desc() */
        WRITE_ONCE(*dst, cpu_to_le64(val));
}

static void arm_smmu_sync_ste_for_sid(struct arm_smmu_device *smmu, u32 sid)
{
        struct arm_smmu_cmdq_ent cmd = {
                .opcode = CMDQ_OP_CFGI_STE,
                .cfgi   = {
                        .sid    = sid,
                        .leaf   = true,
                },
        };

        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        arm_smmu_cmdq_issue_sync(smmu);
}

static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
                                      __le64 *dst)
{
        /*
         * This is hideously complicated, but we only really care about
         * three cases at the moment:
         *
         * 1. Invalid (all zero) -> bypass/fault (init)
         * 2. Bypass/fault -> translation/bypass (attach)
         * 3. Translation/bypass -> bypass/fault (detach)
         *
         * Given that we can't update the STE atomically and the SMMU
         * doesn't read the thing in a defined order, that leaves us
         * with the following maintenance requirements:
         *
         * 1. Update Config, return (init time STEs aren't live)
         * 2. Write everything apart from dword 0, sync, write dword 0, sync
         * 3. Update Config, sync
         */
        u64 val = le64_to_cpu(dst[0]);
        bool ste_live = false;
        struct arm_smmu_device *smmu = NULL;
        struct arm_smmu_s1_cfg *s1_cfg = NULL;
        struct arm_smmu_s2_cfg *s2_cfg = NULL;
        struct arm_smmu_domain *smmu_domain = NULL;
        struct arm_smmu_cmdq_ent prefetch_cmd = {
                .opcode         = CMDQ_OP_PREFETCH_CFG,
                .prefetch       = {
                        .sid    = sid,
                },
        };

        if (master) {
                smmu_domain = master->domain;
                smmu = master->smmu;
        }

        if (smmu_domain) {
                switch (smmu_domain->stage) {
                case ARM_SMMU_DOMAIN_S1:
                        s1_cfg = &smmu_domain->s1_cfg;
                        break;
                case ARM_SMMU_DOMAIN_S2:
                case ARM_SMMU_DOMAIN_NESTED:
                        s2_cfg = &smmu_domain->s2_cfg;
                        break;
                default:
                        break;
                }
        }

        if (val & STRTAB_STE_0_V) {
                switch (FIELD_GET(STRTAB_STE_0_CFG, val)) {
                case STRTAB_STE_0_CFG_BYPASS:
                        break;
                case STRTAB_STE_0_CFG_S1_TRANS:
                case STRTAB_STE_0_CFG_S2_TRANS:
                        ste_live = true;
                        break;
                case STRTAB_STE_0_CFG_ABORT:
                        BUG_ON(!disable_bypass);
                        break;
                default:
                        BUG(); /* STE corruption */
                }
        }

        /* Nuke the existing STE_0 value, as we're going to rewrite it */
        val = STRTAB_STE_0_V;

        /* Bypass/fault */
        if (!smmu_domain || !(s1_cfg || s2_cfg)) {
                if (!smmu_domain && disable_bypass)
                        val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_ABORT);
                else
                        val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_BYPASS);

                dst[0] = cpu_to_le64(val);
                dst[1] = cpu_to_le64(FIELD_PREP(STRTAB_STE_1_SHCFG,
                                                STRTAB_STE_1_SHCFG_INCOMING));
                dst[2] = 0; /* Nuke the VMID */
                /*
                 * The SMMU can perform negative caching, so we must sync
                 * the STE regardless of whether the old value was live.
                 */
                if (smmu)
                        arm_smmu_sync_ste_for_sid(smmu, sid);
                return;
        }

        if (s1_cfg) {
                BUG_ON(ste_live);
                dst[1] = cpu_to_le64(
                         FIELD_PREP(STRTAB_STE_1_S1DSS, STRTAB_STE_1_S1DSS_SSID0) |
                         FIELD_PREP(STRTAB_STE_1_S1CIR, STRTAB_STE_1_S1C_CACHE_WBRA) |
                         FIELD_PREP(STRTAB_STE_1_S1COR, STRTAB_STE_1_S1C_CACHE_WBRA) |
                         FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) |
                         FIELD_PREP(STRTAB_STE_1_STRW, STRTAB_STE_1_STRW_NSEL1));

                if (smmu->features & ARM_SMMU_FEAT_STALLS &&
                   !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE))
                        dst[1] |= cpu_to_le64(STRTAB_STE_1_S1STALLD);

                val |= (s1_cfg->cdcfg.cdtab_dma & STRTAB_STE_0_S1CTXPTR_MASK) |
                        FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS) |
                        FIELD_PREP(STRTAB_STE_0_S1CDMAX, s1_cfg->s1cdmax) |
                        FIELD_PREP(STRTAB_STE_0_S1FMT, s1_cfg->s1fmt);
        }

        if (s2_cfg) {
                BUG_ON(ste_live);
                dst[2] = cpu_to_le64(
                         FIELD_PREP(STRTAB_STE_2_S2VMID, s2_cfg->vmid) |
                         FIELD_PREP(STRTAB_STE_2_VTCR, s2_cfg->vtcr) |
#ifdef __BIG_ENDIAN
                         STRTAB_STE_2_S2ENDI |
#endif
                         STRTAB_STE_2_S2PTW | STRTAB_STE_2_S2AA64 |
                         STRTAB_STE_2_S2R);

                dst[3] = cpu_to_le64(s2_cfg->vttbr & STRTAB_STE_3_S2TTB_MASK);

                val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S2_TRANS);
        }

        if (master->ats_enabled)
                dst[1] |= cpu_to_le64(FIELD_PREP(STRTAB_STE_1_EATS,
                                                 STRTAB_STE_1_EATS_TRANS));

        arm_smmu_sync_ste_for_sid(smmu, sid);
        /* See comment in arm_smmu_write_ctx_desc() */
        WRITE_ONCE(dst[0], cpu_to_le64(val));
        arm_smmu_sync_ste_for_sid(smmu, sid);

        /* It's likely that we'll want to use the new STE soon */
        if (!(smmu->options & ARM_SMMU_OPT_SKIP_PREFETCH))
                arm_smmu_cmdq_issue_cmd(smmu, &prefetch_cmd);
}

static void arm_smmu_init_bypass_stes(u64 *strtab, unsigned int nent)
{
        unsigned int i;

        for (i = 0; i < nent; ++i) {
                arm_smmu_write_strtab_ent(NULL, -1, strtab);
                strtab += STRTAB_STE_DWORDS;
        }
}

static int arm_smmu_init_l2_strtab(struct arm_smmu_device *smmu, u32 sid)
{
        size_t size;
        void *strtab;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
        struct arm_smmu_strtab_l1_desc *desc = &cfg->l1_desc[sid >> STRTAB_SPLIT];

        if (desc->l2ptr)
                return 0;

        size = 1 << (STRTAB_SPLIT + ilog2(STRTAB_STE_DWORDS) + 3);
        strtab = &cfg->strtab[(sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS];

        desc->span = STRTAB_SPLIT + 1;
        desc->l2ptr = dmam_alloc_coherent(smmu->dev, size, &desc->l2ptr_dma,
                                          GFP_KERNEL);
        if (!desc->l2ptr) {
                dev_err(smmu->dev,
                        "failed to allocate l2 stream table for SID %u\n",
                        sid);
                return -ENOMEM;
        }

        arm_smmu_init_bypass_stes(desc->l2ptr, 1 << STRTAB_SPLIT);
        arm_smmu_write_strtab_l1_desc(strtab, desc);
        return 0;
}

/* IRQ and event handlers */
static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
{
        int i;
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->evtq.q;
        struct arm_smmu_ll_queue *llq = &q->llq;
        u64 evt[EVTQ_ENT_DWORDS];

        do {
                while (!queue_remove_raw(q, evt)) {
                        u8 id = FIELD_GET(EVTQ_0_ID, evt[0]);

                        dev_info(smmu->dev, "event 0x%02x received:\n", id);
                        for (i = 0; i < ARRAY_SIZE(evt); ++i)
                                dev_info(smmu->dev, "\t0x%016llx\n",
                                         (unsigned long long)evt[i]);

                }

                /*

                 * Not much we can do on overflow, so scream and pretend we're
                 * trying harder.
                 */
                if (queue_sync_prod_in(q) == -EOVERFLOW)
                        dev_err(smmu->dev, "EVTQ overflow detected -- events lost\n");
        } while (!queue_empty(llq));

        /* Sync our overflow flag, as we believe we're up to speed */
        llq->cons = Q_OVF(llq->prod) | Q_WRP(llq, llq->cons) |
                    Q_IDX(llq, llq->cons);
        return IRQ_HANDLED;
}

static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
{
        u32 sid, ssid;
        u16 grpid;
        bool ssv, last;

        sid = FIELD_GET(PRIQ_0_SID, evt[0]);
        ssv = FIELD_GET(PRIQ_0_SSID_V, evt[0]);
        ssid = ssv ? FIELD_GET(PRIQ_0_SSID, evt[0]) : 0;
        last = FIELD_GET(PRIQ_0_PRG_LAST, evt[0]);
        grpid = FIELD_GET(PRIQ_1_PRG_IDX, evt[1]);

        dev_info(smmu->dev, "unexpected PRI request received:\n");
        dev_info(smmu->dev,
                 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
                 sid, ssid, grpid, last ? "L" : "",
                 evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
                 evt[0] & PRIQ_0_PERM_READ ? "R" : "",
                 evt[0] & PRIQ_0_PERM_WRITE ? "W" : "",
                 evt[0] & PRIQ_0_PERM_EXEC ? "X" : "",
                 evt[1] & PRIQ_1_ADDR_MASK);

        if (last) {
                struct arm_smmu_cmdq_ent cmd = {
                        .opcode                 = CMDQ_OP_PRI_RESP,
                        .substream_valid        = ssv,
                        .pri                    = {
                                .sid    = sid,
                                .ssid   = ssid,
                                .grpid  = grpid,
                                .resp   = PRI_RESP_DENY,
                        },
                };

                arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        }
}

static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
{
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->priq.q;
        struct arm_smmu_ll_queue *llq = &q->llq;
        u64 evt[PRIQ_ENT_DWORDS];

        do {
                while (!queue_remove_raw(q, evt))
                        arm_smmu_handle_ppr(smmu, evt);

                if (queue_sync_prod_in(q) == -EOVERFLOW)
                        dev_err(smmu->dev, "PRIQ overflow detected -- requests lost\n");
        } while (!queue_empty(llq));

        /* Sync our overflow flag, as we believe we're up to speed */
        llq->cons = Q_OVF(llq->prod) | Q_WRP(llq, llq->cons) |
                      Q_IDX(llq, llq->cons);
        queue_sync_cons_out(q);
        return IRQ_HANDLED;
}

static int arm_smmu_device_disable(struct arm_smmu_device *smmu);

static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
{
        u32 gerror, gerrorn, active;
        struct arm_smmu_device *smmu = dev;

        gerror = readl_relaxed(smmu->base + ARM_SMMU_GERROR);
        gerrorn = readl_relaxed(smmu->base + ARM_SMMU_GERRORN);

        active = gerror ^ gerrorn;
        if (!(active & GERROR_ERR_MASK))
                return IRQ_NONE; /* No errors pending */

        dev_warn(smmu->dev,
                 "unexpected global error reported (0x%08x), this could be serious\n",
                 active);

        if (active & GERROR_SFM_ERR) {
                dev_err(smmu->dev, "device has entered Service Failure Mode!\n");
                arm_smmu_device_disable(smmu);
        }

        if (active & GERROR_MSI_GERROR_ABT_ERR)
                dev_warn(smmu->dev, "GERROR MSI write aborted\n");

        if (active & GERROR_MSI_PRIQ_ABT_ERR)
                dev_warn(smmu->dev, "PRIQ MSI write aborted\n");

        if (active & GERROR_MSI_EVTQ_ABT_ERR)
                dev_warn(smmu->dev, "EVTQ MSI write aborted\n");

        if (active & GERROR_MSI_CMDQ_ABT_ERR)
                dev_warn(smmu->dev, "CMDQ MSI write aborted\n");

        if (active & GERROR_PRIQ_ABT_ERR)
                dev_err(smmu->dev, "PRIQ write aborted -- events may have been lost\n");

        if (active & GERROR_EVTQ_ABT_ERR)
                dev_err(smmu->dev, "EVTQ write aborted -- events may have been lost\n");

        if (active & GERROR_CMDQ_ERR)
                arm_smmu_cmdq_skip_err(smmu);

        writel(gerror, smmu->base + ARM_SMMU_GERRORN);
        return IRQ_HANDLED;
}

static irqreturn_t arm_smmu_combined_irq_thread(int irq, void *dev)
{
        struct arm_smmu_device *smmu = dev;

        arm_smmu_evtq_thread(irq, dev);
        if (smmu->features & ARM_SMMU_FEAT_PRI)
                arm_smmu_priq_thread(irq, dev);

        return IRQ_HANDLED;
}

static irqreturn_t arm_smmu_combined_irq_handler(int irq, void *dev)
{
        arm_smmu_gerror_handler(irq, dev);
        return IRQ_WAKE_THREAD;
}

static void
arm_smmu_atc_inv_to_cmd(int ssid, unsigned long iova, size_t size,
                        struct arm_smmu_cmdq_ent *cmd)
{
        size_t log2_span;
        size_t span_mask;
        /* ATC invalidates are always on 4096-bytes pages */
        size_t inval_grain_shift = 12;
        unsigned long page_start, page_end;

        *cmd = (struct arm_smmu_cmdq_ent) {
                .opcode                 = CMDQ_OP_ATC_INV,
                .substream_valid        = !!ssid,
                .atc.ssid               = ssid,
        };

        if (!size) {
                cmd->atc.size = ATC_INV_SIZE_ALL;
                return;
        }

        page_start      = iova >> inval_grain_shift;
        page_end        = (iova + size - 1) >> inval_grain_shift;

        /*
         * In an ATS Invalidate Request, the address must be aligned on the
         * range size, which must be a power of two number of page sizes. We
         * thus have to choose between grossly over-invalidating the region, or
         * splitting the invalidation into multiple commands. For simplicity
         * we'll go with the first solution, but should refine it in the future
         * if multiple commands are shown to be more efficient.
         *
         * Find the smallest power of two that covers the range. The most
         * significant differing bit between the start and end addresses,
         * fls(start ^ end), indicates the required span. For example:
         *
         * We want to invalidate pages [8; 11]. This is already the ideal range:
         *              x = 0b1000 ^ 0b1011 = 0b11
         *              span = 1 << fls(x) = 4
         *
         * To invalidate pages [7; 10], we need to invalidate [0; 15]:
         *              x = 0b0111 ^ 0b1010 = 0b1101
         *              span = 1 << fls(x) = 16
         */
        log2_span       = fls_long(page_start ^ page_end);
        span_mask       = (1ULL << log2_span) - 1;

        page_start      &= ~span_mask;

        cmd->atc.addr   = page_start << inval_grain_shift;
        cmd->atc.size   = log2_span;
}

static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
{
        int i;
        struct arm_smmu_cmdq_ent cmd;

        arm_smmu_atc_inv_to_cmd(0, 0, 0, &cmd);

        for (i = 0; i < master->num_sids; i++) {
                cmd.atc.sid = master->sids[i];
                arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
        }

        return arm_smmu_cmdq_issue_sync(master->smmu);
}

static int arm_smmu_atc_inv_domain(struct arm_smmu_domain *smmu_domain,
                                   int ssid, unsigned long iova, size_t size)
{
        int i;
        unsigned long flags;
        struct arm_smmu_cmdq_ent cmd;
        struct arm_smmu_master *master;
        struct arm_smmu_cmdq_batch cmds = {};

        if (!(smmu_domain->smmu->features & ARM_SMMU_FEAT_ATS))
                return 0;

        /*
         * Ensure that we've completed prior invalidation of the main TLBs
         * before we read 'nr_ats_masters' in case of a concurrent call to
         * arm_smmu_enable_ats():
         *
         *      // unmap()                      // arm_smmu_enable_ats()
         *      TLBI+SYNC                       atomic_inc(&nr_ats_masters);
         *      smp_mb();                       [...]
         *      atomic_read(&nr_ats_masters);   pci_enable_ats() // writel()
         *
         * Ensures that we always see the incremented 'nr_ats_masters' count if
         * ATS was enabled at the PCI device before completion of the TLBI.
         */
        smp_mb();
        if (!atomic_read(&smmu_domain->nr_ats_masters))
                return 0;

        arm_smmu_atc_inv_to_cmd(ssid, iova, size, &cmd);

        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
        list_for_each_entry(master, &smmu_domain->devices, domain_head) {
                if (!master->ats_enabled)
                        continue;

                for (i = 0; i < master->num_sids; i++) {
                        cmd.atc.sid = master->sids[i];
                        arm_smmu_cmdq_batch_add(smmu_domain->smmu, &cmds, &cmd);
                }
        }
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

        return arm_smmu_cmdq_batch_submit(smmu_domain->smmu, &cmds);
}

/* IO_PGTABLE API */
static void arm_smmu_tlb_inv_context(void *cookie)
{
        struct arm_smmu_domain *smmu_domain = cookie;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_cmdq_ent cmd;

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                cmd.opcode      = CMDQ_OP_TLBI_NH_ASID;
                cmd.tlbi.asid   = smmu_domain->s1_cfg.cd.asid;
                cmd.tlbi.vmid   = 0;
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S12_VMALL;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
        }

        /*
         * NOTE: when io-pgtable is in non-strict mode, we may get here with
         * PTEs previously cleared by unmaps on the current CPU not yet visible
         * to the SMMU. We are relying on the dma_wmb() implicit during cmd
         * insertion to guarantee those are observed before the TLBI. Do be
         * careful, 007.
         */
        arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        arm_smmu_cmdq_issue_sync(smmu);
        arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
}

static void arm_smmu_tlb_inv_range(unsigned long iova, size_t size,
                                   size_t granule, bool leaf,
                                   struct arm_smmu_domain *smmu_domain)
{
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        unsigned long start = iova, end = iova + size, num_pages = 0, tg = 0;
        size_t inv_range = granule;
        struct arm_smmu_cmdq_batch cmds = {};
        struct arm_smmu_cmdq_ent cmd = {
                .tlbi = {
                        .leaf   = leaf,
                },
        };

        if (!size)
                return;

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                cmd.opcode      = CMDQ_OP_TLBI_NH_VA;
                cmd.tlbi.asid   = smmu_domain->s1_cfg.cd.asid;
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S2_IPA;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
        }

        if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
                /* Get the leaf page size */
                tg = __ffs(smmu_domain->domain.pgsize_bitmap);

                /* Convert page size of 12,14,16 (log2) to 1,2,3 */
                cmd.tlbi.tg = (tg - 10) / 2;

                /* Determine what level the granule is at */
                cmd.tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));

                num_pages = size >> tg;
        }

        while (iova < end) {
                if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
                        /*
                         * On each iteration of the loop, the range is 5 bits
                         * worth of the aligned size remaining.
                         * The range in pages is:
                         *
                         * range = (num_pages & (0x1f << __ffs(num_pages)))
                         */
                        unsigned long scale, num;

                        /* Determine the power of 2 multiple number of pages */
                        scale = __ffs(num_pages);
                        cmd.tlbi.scale = scale;

                        /* Determine how many chunks of 2^scale size we have */
                        num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX;
                        cmd.tlbi.num = num - 1;

                        /* range is num * 2^scale * pgsize */
                        inv_range = num << (scale + tg);

                        /* Clear out the lower order bits for the next iteration */
                        num_pages -= num << scale;
                }

                cmd.tlbi.addr = iova;
                arm_smmu_cmdq_batch_add(smmu, &cmds, &cmd);
                iova += inv_range;
        }
        arm_smmu_cmdq_batch_submit(smmu, &cmds);

        /*
         * Unfortunately, this can't be leaf-only since we may have
         * zapped an entire table.
         */
        arm_smmu_atc_inv_domain(smmu_domain, 0, start, size);
}

static void arm_smmu_tlb_inv_page_nosync(struct iommu_iotlb_gather *gather,
                                         unsigned long iova, size_t granule,
                                         void *cookie)
{
        struct arm_smmu_domain *smmu_domain = cookie;
        struct iommu_domain *domain = &smmu_domain->domain;

        iommu_iotlb_gather_add_page(domain, gather, iova, granule);
}

static void arm_smmu_tlb_inv_walk(unsigned long iova, size_t size,
                                  size_t granule, void *cookie)
{
        arm_smmu_tlb_inv_range(iova, size, granule, false, cookie);
}

static void arm_smmu_tlb_inv_leaf(unsigned long iova, size_t size,
                                  size_t granule, void *cookie)
{
        arm_smmu_tlb_inv_range(iova, size, granule, true, cookie);
}

static const struct iommu_flush_ops arm_smmu_flush_ops = {
        .tlb_flush_all  = arm_smmu_tlb_inv_context,
        .tlb_flush_walk = arm_smmu_tlb_inv_walk,
        .tlb_flush_leaf = arm_smmu_tlb_inv_leaf,
        .tlb_add_page   = arm_smmu_tlb_inv_page_nosync,
};

/* IOMMU API */
static bool arm_smmu_capable(enum iommu_cap cap)
{
        switch (cap) {
        case IOMMU_CAP_CACHE_COHERENCY:
                return true;
        case IOMMU_CAP_NOEXEC:
                return true;
        default:
                return false;
        }
}

static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
{
        struct arm_smmu_domain *smmu_domain;

        if (type != IOMMU_DOMAIN_UNMANAGED &&
            type != IOMMU_DOMAIN_DMA &&
            type != IOMMU_DOMAIN_IDENTITY)
                return NULL;

        /*
         * Allocate the domain and initialise some of its data structures.
         * We can't really do anything meaningful until we've added a
         * master.
         */
        smmu_domain = kzalloc(sizeof(*smmu_domain), GFP_KERNEL);
        if (!smmu_domain)
                return NULL;

        if (type == IOMMU_DOMAIN_DMA &&
            iommu_get_dma_cookie(&smmu_domain->domain)) {
                kfree(smmu_domain);
                return NULL;
        }

        mutex_init(&smmu_domain->init_mutex);
        INIT_LIST_HEAD(&smmu_domain->devices);
        spin_lock_init(&smmu_domain->devices_lock);

        return &smmu_domain->domain;
}

static int arm_smmu_bitmap_alloc(unsigned long *map, int span)
{
        int idx, size = 1 << span;

        do {
                idx = find_first_zero_bit(map, size);
                if (idx == size)
                        return -ENOSPC;
        } while (test_and_set_bit(idx, map));

        return idx;
}

static void arm_smmu_bitmap_free(unsigned long *map, int idx)
{
        clear_bit(idx, map);
}

static void arm_smmu_domain_free(struct iommu_domain *domain)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_device *smmu = smmu_domain->smmu;

        iommu_put_dma_cookie(domain);
        free_io_pgtable_ops(smmu_domain->pgtbl_ops);

        /* Free the CD and ASID, if we allocated them */
        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;

                if (cfg->cdcfg.cdtab)
                        arm_smmu_free_cd_tables(smmu_domain);
                arm_smmu_free_asid(&cfg->cd);
        } else {
                struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
                if (cfg->vmid)
                        arm_smmu_bitmap_free(smmu->vmid_map, cfg->vmid);
        }

        kfree(smmu_domain);
}

static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
                                       struct arm_smmu_master *master,
                                       struct io_pgtable_cfg *pgtbl_cfg)
{
        int ret;
        u32 asid;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_s1_cfg *cfg = &smmu_domain->s1_cfg;
        typeof(&pgtbl_cfg->arm_lpae_s1_cfg.tcr) tcr = &pgtbl_cfg->arm_lpae_s1_cfg.tcr;

        ret = xa_alloc(&asid_xa, &asid, &cfg->cd,
                       XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
        if (ret)
                return ret;

        cfg->s1cdmax = master->ssid_bits;

        ret = arm_smmu_alloc_cd_tables(smmu_domain);
        if (ret)
                goto out_free_asid;

        cfg->cd.asid    = (u16)asid;
        cfg->cd.ttbr    = pgtbl_cfg->arm_lpae_s1_cfg.ttbr;
        cfg->cd.tcr     = FIELD_PREP(CTXDESC_CD_0_TCR_T0SZ, tcr->tsz) |
                          FIELD_PREP(CTXDESC_CD_0_TCR_TG0, tcr->tg) |
                          FIELD_PREP(CTXDESC_CD_0_TCR_IRGN0, tcr->irgn) |
                          FIELD_PREP(CTXDESC_CD_0_TCR_ORGN0, tcr->orgn) |
                          FIELD_PREP(CTXDESC_CD_0_TCR_SH0, tcr->sh) |
                          FIELD_PREP(CTXDESC_CD_0_TCR_IPS, tcr->ips) |
                          CTXDESC_CD_0_TCR_EPD1 | CTXDESC_CD_0_AA64;
        cfg->cd.mair    = pgtbl_cfg->arm_lpae_s1_cfg.mair;

        /*
         * Note that this will end up calling arm_smmu_sync_cd() before
         * the master has been added to the devices list for this domain.
         * This isn't an issue because the STE hasn't been installed yet.
         */
        ret = arm_smmu_write_ctx_desc(smmu_domain, 0, &cfg->cd);
        if (ret)
                goto out_free_cd_tables;

        return 0;

out_free_cd_tables:
        arm_smmu_free_cd_tables(smmu_domain);
out_free_asid:
        arm_smmu_free_asid(&cfg->cd);
        return ret;
}

static int arm_smmu_domain_finalise_s2(struct arm_smmu_domain *smmu_domain,
                                       struct arm_smmu_master *master,
                                       struct io_pgtable_cfg *pgtbl_cfg)
{
        int vmid;
        struct arm_smmu_device *smmu = smmu_domain->smmu;
        struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
        typeof(&pgtbl_cfg->arm_lpae_s2_cfg.vtcr) vtcr;

        vmid = arm_smmu_bitmap_alloc(smmu->vmid_map, smmu->vmid_bits);
        if (vmid < 0)
                return vmid;

        vtcr = &pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
        cfg->vmid       = (u16)vmid;
        cfg->vttbr      = pgtbl_cfg->arm_lpae_s2_cfg.vttbr;
        cfg->vtcr       = FIELD_PREP(STRTAB_STE_2_VTCR_S2T0SZ, vtcr->tsz) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2SL0, vtcr->sl) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2IR0, vtcr->irgn) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2OR0, vtcr->orgn) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2SH0, vtcr->sh) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2TG, vtcr->tg) |
                          FIELD_PREP(STRTAB_STE_2_VTCR_S2PS, vtcr->ps);
        return 0;
}

static int arm_smmu_domain_finalise(struct iommu_domain *domain,
                                    struct arm_smmu_master *master)
{
        int ret;
        unsigned long ias, oas;
        enum io_pgtable_fmt fmt;
        struct io_pgtable_cfg pgtbl_cfg;
        struct io_pgtable_ops *pgtbl_ops;
        int (*finalise_stage_fn)(struct arm_smmu_domain *,
                                 struct arm_smmu_master *,
                                 struct io_pgtable_cfg *);
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_device *smmu = smmu_domain->smmu;

        if (domain->type == IOMMU_DOMAIN_IDENTITY) {
                smmu_domain->stage = ARM_SMMU_DOMAIN_BYPASS;
                return 0;
        }

        /* Restrict the stage to what we can actually support */
        if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S1))
                smmu_domain->stage = ARM_SMMU_DOMAIN_S2;
        if (!(smmu->features & ARM_SMMU_FEAT_TRANS_S2))
                smmu_domain->stage = ARM_SMMU_DOMAIN_S1;

        switch (smmu_domain->stage) {
        case ARM_SMMU_DOMAIN_S1:
                ias = (smmu->features & ARM_SMMU_FEAT_VAX) ? 52 : 48;
                ias = min_t(unsigned long, ias, VA_BITS);
                oas = smmu->ias;
                fmt = ARM_64_LPAE_S1;
                finalise_stage_fn = arm_smmu_domain_finalise_s1;
                break;
        case ARM_SMMU_DOMAIN_NESTED:
        case ARM_SMMU_DOMAIN_S2:
                ias = smmu->ias;
                oas = smmu->oas;
                fmt = ARM_64_LPAE_S2;
                finalise_stage_fn = arm_smmu_domain_finalise_s2;
                break;
        default:
                return -EINVAL;
        }

        pgtbl_cfg = (struct io_pgtable_cfg) {
                .pgsize_bitmap  = smmu->pgsize_bitmap,
                .ias            = ias,
                .oas            = oas,
                .coherent_walk  = smmu->features & ARM_SMMU_FEAT_COHERENCY,
                .tlb            = &arm_smmu_flush_ops,
                .iommu_dev      = smmu->dev,
        };

        if (smmu_domain->non_strict)
                pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

        pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
        if (!pgtbl_ops)
                return -ENOMEM;

        domain->pgsize_bitmap = pgtbl_cfg.pgsize_bitmap;
        domain->geometry.aperture_end = (1UL << pgtbl_cfg.ias) - 1;
        domain->geometry.force_aperture = true;

        ret = finalise_stage_fn(smmu_domain, master, &pgtbl_cfg);
        if (ret < 0) {
                free_io_pgtable_ops(pgtbl_ops);
                return ret;
        }

        smmu_domain->pgtbl_ops = pgtbl_ops;
        return 0;
}

static __le64 *arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)
{
        __le64 *step;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;

        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
                struct arm_smmu_strtab_l1_desc *l1_desc;
                int idx;

                /* Two-level walk */
                idx = (sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS;
                l1_desc = &cfg->l1_desc[idx];
                idx = (sid & ((1 << STRTAB_SPLIT) - 1)) * STRTAB_STE_DWORDS;
                step = &l1_desc->l2ptr[idx];
        } else {
                /* Simple linear lookup */
                step = &cfg->strtab[sid * STRTAB_STE_DWORDS];
        }

        return step;
}

static void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master)
{
        int i, j;
        struct arm_smmu_device *smmu = master->smmu;

        for (i = 0; i < master->num_sids; ++i) {
                u32 sid = master->sids[i];
                __le64 *step = arm_smmu_get_step_for_sid(smmu, sid);

                /* Bridged PCI devices may end up with duplicated IDs */
                for (j = 0; j < i; j++)
                        if (master->sids[j] == sid)
                                break;
                if (j < i)
                        continue;

                arm_smmu_write_strtab_ent(master, sid, step);
        }
}

static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
{
        struct device *dev = master->dev;
        struct arm_smmu_device *smmu = master->smmu;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);

        if (!(smmu->features & ARM_SMMU_FEAT_ATS))
                return false;

        if (!(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS))
                return false;

        return dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev));
}

static void arm_smmu_enable_ats(struct arm_smmu_master *master)
{
        size_t stu;
        struct pci_dev *pdev;
        struct arm_smmu_device *smmu = master->smmu;
        struct arm_smmu_domain *smmu_domain = master->domain;

        /* Don't enable ATS at the endpoint if it's not enabled in the STE */
        if (!master->ats_enabled)
                return;

        /* Smallest Translation Unit: log2 of the smallest supported granule */
        stu = __ffs(smmu->pgsize_bitmap);
        pdev = to_pci_dev(master->dev);

        atomic_inc(&smmu_domain->nr_ats_masters);
        arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
        if (pci_enable_ats(pdev, stu))
                dev_err(master->dev, "Failed to enable ATS (STU %zu)\n", stu);
}

static void arm_smmu_disable_ats(struct arm_smmu_master *master)
{
        struct arm_smmu_domain *smmu_domain = master->domain;

        if (!master->ats_enabled)
                return;

        pci_disable_ats(to_pci_dev(master->dev));
        /*
         * Ensure ATS is disabled at the endpoint before we issue the
         * ATC invalidation via the SMMU.
         */
        wmb();
        arm_smmu_atc_inv_master(master);
        atomic_dec(&smmu_domain->nr_ats_masters);
}

static int arm_smmu_enable_pasid(struct arm_smmu_master *master)
{
        int ret;
        int features;
        int num_pasids;
        struct pci_dev *pdev;

        if (!dev_is_pci(master->dev))
                return -ENODEV;

        pdev = to_pci_dev(master->dev);

        features = pci_pasid_features(pdev);
        if (features < 0)
                return features;

        num_pasids = pci_max_pasids(pdev);
        if (num_pasids <= 0)
                return num_pasids;

        ret = pci_enable_pasid(pdev, features);
        if (ret) {
                dev_err(&pdev->dev, "Failed to enable PASID\n");
                return ret;
        }

        master->ssid_bits = min_t(u8, ilog2(num_pasids),
                                  master->smmu->ssid_bits);
        return 0;
}

static void arm_smmu_disable_pasid(struct arm_smmu_master *master)
{
        struct pci_dev *pdev;

        if (!dev_is_pci(master->dev))
                return;

        pdev = to_pci_dev(master->dev);

        if (!pdev->pasid_enabled)
                return;

        master->ssid_bits = 0;
        pci_disable_pasid(pdev);
}

static void arm_smmu_detach_dev(struct arm_smmu_master *master)
{
        unsigned long flags;
        struct arm_smmu_domain *smmu_domain = master->domain;

        if (!smmu_domain)
                return;

        arm_smmu_disable_ats(master);

        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
        list_del(&master->domain_head);
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

        master->domain = NULL;
        master->ats_enabled = false;
        arm_smmu_install_ste_for_dev(master);
}

static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
{
        int ret = 0;
        unsigned long flags;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
        struct arm_smmu_device *smmu;
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct arm_smmu_master *master;

        if (!fwspec)
                return -ENOENT;

        master = dev_iommu_priv_get(dev);
        smmu = master->smmu;

        arm_smmu_detach_dev(master);

        mutex_lock(&smmu_domain->init_mutex);

        if (!smmu_domain->smmu) {
                smmu_domain->smmu = smmu;
                ret = arm_smmu_domain_finalise(domain, master);
                if (ret) {
                        smmu_domain->smmu = NULL;
                        goto out_unlock;
                }
        } else if (smmu_domain->smmu != smmu) {
                dev_err(dev,
                        "cannot attach to SMMU %s (upstream of %s)\n",
                        dev_name(smmu_domain->smmu->dev),
                        dev_name(smmu->dev));
                ret = -ENXIO;
                goto out_unlock;
        } else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
                   master->ssid_bits != smmu_domain->s1_cfg.s1cdmax) {
                dev_err(dev,
                        "cannot attach to incompatible domain (%u SSID bits != %u)\n",
                        smmu_domain->s1_cfg.s1cdmax, master->ssid_bits);
                ret = -EINVAL;
                goto out_unlock;
        }

        master->domain = smmu_domain;

        if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
                master->ats_enabled = arm_smmu_ats_supported(master);

        arm_smmu_install_ste_for_dev(master);

        spin_lock_irqsave(&smmu_domain->devices_lock, flags);
        list_add(&master->domain_head, &smmu_domain->devices);
        spin_unlock_irqrestore(&smmu_domain->devices_lock, flags);

        arm_smmu_enable_ats(master);

out_unlock:
        mutex_unlock(&smmu_domain->init_mutex);
        return ret;
}

static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
                        phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
{
        struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;

        if (!ops)
                return -ENODEV;

        return ops->map(ops, iova, paddr, size, prot, gfp);
}

static size_t arm_smmu_unmap(struct iommu_domain *domain, unsigned long iova,
                             size_t size, struct iommu_iotlb_gather *gather)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops;

        if (!ops)
                return 0;

        return ops->unmap(ops, iova, size, gather);
}

static void arm_smmu_flush_iotlb_all(struct iommu_domain *domain)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

        if (smmu_domain->smmu)
                arm_smmu_tlb_inv_context(smmu_domain);
}

static void arm_smmu_iotlb_sync(struct iommu_domain *domain,
                                struct iommu_iotlb_gather *gather)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

        arm_smmu_tlb_inv_range(gather->start, gather->end - gather->start,
                               gather->pgsize, true, smmu_domain);
}

static phys_addr_t
arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
{
        struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;

        if (domain->type == IOMMU_DOMAIN_IDENTITY)
                return iova;

        if (!ops)
                return 0;

        return ops->iova_to_phys(ops, iova);
}

static struct platform_driver arm_smmu_driver;

static
struct arm_smmu_device *arm_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
{
        struct device *dev = driver_find_device_by_fwnode(&arm_smmu_driver.driver,
                                                          fwnode);
        put_device(dev);
        return dev ? dev_get_drvdata(dev) : NULL;
}

static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
{
        unsigned long limit = smmu->strtab_cfg.num_l1_ents;

        if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)
                limit *= 1UL << STRTAB_SPLIT;

        return sid < limit;
}

static struct iommu_ops arm_smmu_ops;

static struct iommu_device *arm_smmu_probe_device(struct device *dev)
{
        int i, ret;
        struct arm_smmu_device *smmu;
        struct arm_smmu_master *master;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);

        if (!fwspec || fwspec->ops != &arm_smmu_ops)
                return ERR_PTR(-ENODEV);

        if (WARN_ON_ONCE(dev_iommu_priv_get(dev)))
                return ERR_PTR(-EBUSY);

        smmu = arm_smmu_get_by_fwnode(fwspec->iommu_fwnode);
        if (!smmu)
                return ERR_PTR(-ENODEV);

        master = kzalloc(sizeof(*master), GFP_KERNEL);
        if (!master)
                return ERR_PTR(-ENOMEM);

        master->dev = dev;
        master->smmu = smmu;
        master->sids = fwspec->ids;
        master->num_sids = fwspec->num_ids;
        dev_iommu_priv_set(dev, master);

        /* Check the SIDs are in range of the SMMU and our stream table */
        for (i = 0; i < master->num_sids; i++) {
                u32 sid = master->sids[i];

                if (!arm_smmu_sid_in_range(smmu, sid)) {
                        ret = -ERANGE;
                        goto err_free_master;
                }

                /* Ensure l2 strtab is initialised */
                if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
                        ret = arm_smmu_init_l2_strtab(smmu, sid);
                        if (ret)
                                goto err_free_master;
                }
        }

        master->ssid_bits = min(smmu->ssid_bits, fwspec->num_pasid_bits);

        /*
         * Note that PASID must be enabled before, and disabled after ATS:
         * PCI Express Base 4.0r1.0 - 10.5.1.3 ATS Control Register
         *
         *   Behavior is undefined if this bit is Set and the value of the PASID
         *   Enable, Execute Requested Enable, or Privileged Mode Requested bits
         *   are changed.
         */
        arm_smmu_enable_pasid(master);

        if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_CDTAB))
                master->ssid_bits = min_t(u8, master->ssid_bits,
                                          CTXDESC_LINEAR_CDMAX);

        return &smmu->iommu;

err_free_master:
        kfree(master);
        dev_iommu_priv_set(dev, NULL);
        return ERR_PTR(ret);
}

static void arm_smmu_release_device(struct device *dev)
{
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
        struct arm_smmu_master *master;

        if (!fwspec || fwspec->ops != &arm_smmu_ops)
                return;

        master = dev_iommu_priv_get(dev);
        arm_smmu_detach_dev(master);
        arm_smmu_disable_pasid(master);
        kfree(master);