// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013-2017 ARM Limited, All Rights Reserved.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 */

#include <linux/acpi.h>
#include <linux/acpi_iort.h>
#include <linux/bitmap.h>
#include <linux/cpu.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
#include <linux/dma-iommu.h>
#include <linux/efi.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/list.h>
#include <linux/log2.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/msi.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/syscore_ops.h>

#include <linux/irqchip.h>
#include <linux/irqchip/arm-gic-v3.h>
#include <linux/irqchip/arm-gic-v4.h>

#include <asm/cputype.h>
#include <asm/exception.h>

#include "irq-gic-common.h"

#define ITS_FLAGS_CMDQ_NEEDS_FLUSHING           (1ULL << 0)
#define ITS_FLAGS_WORKAROUND_CAVIUM_22375       (1ULL << 1)
#define ITS_FLAGS_WORKAROUND_CAVIUM_23144       (1ULL << 2)
#define ITS_FLAGS_SAVE_SUSPEND_STATE            (1ULL << 3)

#define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING     (1 << 0)
#define RDIST_FLAGS_RD_TABLES_PREALLOCATED      (1 << 1)

static u32 lpi_id_bits;

/*
 * We allocate memory for PROPBASE to cover 2 ^ lpi_id_bits LPIs to
 * deal with (one configuration byte per interrupt). PENDBASE has to
 * be 64kB aligned (one bit per LPI, plus 8192 bits for SPI/PPI/SGI).
 */
#define LPI_NRBITS              lpi_id_bits
#define LPI_PROPBASE_SZ         ALIGN(BIT(LPI_NRBITS), SZ_64K)
#define LPI_PENDBASE_SZ         ALIGN(BIT(LPI_NRBITS) / 8, SZ_64K)

#define LPI_PROP_DEFAULT_PRIO   GICD_INT_DEF_PRI

/*
 * Collection structure - just an ID, and a redistributor address to
 * ping. We use one per CPU as a bag of interrupts assigned to this
 * CPU.
 */
struct its_collection {
        u64                     target_address;
        u16                     col_id;
};

/*
 * The ITS_BASER structure - contains memory information, cached
 * value of BASER register configuration and ITS page size.
 */
struct its_baser {
        void            *base;
        u64             val;
        u32             order;
        u32             psz;
};

struct its_device;

/*
 * The ITS structure - contains most of the infrastructure, with the
 * top-level MSI domain, the command queue, the collections, and the
 * list of devices writing to it.
 *
 * dev_alloc_lock has to be taken for device allocations, while the
 * spinlock must be taken to parse data structures such as the device
 * list.
 */
struct its_node {
        raw_spinlock_t          lock;
        struct mutex            dev_alloc_lock;
        struct list_head        entry;
        void __iomem            *base;
        phys_addr_t             phys_base;
        struct its_cmd_block    *cmd_base;
        struct its_cmd_block    *cmd_write;
        struct its_baser        tables[GITS_BASER_NR_REGS];
        struct its_collection   *collections;
        struct fwnode_handle    *fwnode_handle;
        u64                     (*get_msi_base)(struct its_device *its_dev);
        u64                     cbaser_save;
        u32                     ctlr_save;
        struct list_head        its_device_list;
        u64                     flags;
        unsigned long           list_nr;
        u32                     ite_size;
        u32                     device_ids;
        int                     numa_node;
        unsigned int            msi_domain_flags;
        u32                     pre_its_base; /* for Socionext Synquacer */
        bool                    is_v4;
        int                     vlpi_redist_offset;
};

#define ITS_ITT_ALIGN           SZ_256

/* The maximum number of VPEID bits supported by VLPI commands */
#define ITS_MAX_VPEID_BITS      (16)
#define ITS_MAX_VPEID           (1 << (ITS_MAX_VPEID_BITS))

/* Convert page order to size in bytes */
#define PAGE_ORDER_TO_SIZE(o)   (PAGE_SIZE << (o))

struct event_lpi_map {
        unsigned long           *lpi_map;
        u16                     *col_map;
        irq_hw_number_t         lpi_base;
        int                     nr_lpis;
        struct mutex            vlpi_lock;
        struct its_vm           *vm;
        struct its_vlpi_map     *vlpi_maps;
        int                     nr_vlpis;
};

/*
 * The ITS view of a device - belongs to an ITS, owns an interrupt
 * translation table, and a list of interrupts.  If it some of its
 * LPIs are injected into a guest (GICv4), the event_map.vm field
 * indicates which one.
 */
struct its_device {
        struct list_head        entry;
        struct its_node         *its;
        struct event_lpi_map    event_map;
        void                    *itt;
        u32                     nr_ites;
        u32                     device_id;
        bool                    shared;
};

static struct {
        raw_spinlock_t          lock;
        struct its_device       *dev;
        struct its_vpe          **vpes;
        int                     next_victim;
} vpe_proxy;

static LIST_HEAD(its_nodes);
static DEFINE_RAW_SPINLOCK(its_lock);
static struct rdists *gic_rdists;
static struct irq_domain *its_parent;

static unsigned long its_list_map;
static u16 vmovp_seq_num;
static DEFINE_RAW_SPINLOCK(vmovp_lock);

static DEFINE_IDA(its_vpeid_ida);

#define gic_data_rdist()                (raw_cpu_ptr(gic_rdists->rdist))
#define gic_data_rdist_cpu(cpu)         (per_cpu_ptr(gic_rdists->rdist, cpu))
#define gic_data_rdist_rd_base()        (gic_data_rdist()->rd_base)
#define gic_data_rdist_vlpi_base()      (gic_data_rdist_rd_base() + SZ_128K)

static struct its_collection *dev_event_to_col(struct its_device *its_dev,
                                               u32 event)
{
        struct its_node *its = its_dev->its;

        return its->collections + its_dev->event_map.col_map[event];
}

static struct its_collection *valid_col(struct its_collection *col)
{
        if (WARN_ON_ONCE(col->target_address & GENMASK_ULL(15, 0)))
                return NULL;

        return col;
}

static struct its_vpe *valid_vpe(struct its_node *its, struct its_vpe *vpe)
{
        if (valid_col(its->collections + vpe->col_idx))
                return vpe;

        return NULL;
}

/*
 * ITS command descriptors - parameters to be encoded in a command
 * block.
 */
struct its_cmd_desc {
        union {
                struct {
                        struct its_device *dev;
                        u32 event_id;
                } its_inv_cmd;

                struct {
                        struct its_device *dev;
                        u32 event_id;
                } its_clear_cmd;

                struct {
                        struct its_device *dev;
                        u32 event_id;
                } its_int_cmd;

                struct {
                        struct its_device *dev;
                        int valid;
                } its_mapd_cmd;

                struct {
                        struct its_collection *col;
                        int valid;
                } its_mapc_cmd;

                struct {
                        struct its_device *dev;
                        u32 phys_id;
                        u32 event_id;
                } its_mapti_cmd;

                struct {
                        struct its_device *dev;
                        struct its_collection *col;
                        u32 event_id;
                } its_movi_cmd;

                struct {
                        struct its_device *dev;
                        u32 event_id;
                } its_discard_cmd;

                struct {
                        struct its_collection *col;
                } its_invall_cmd;

                struct {
                        struct its_vpe *vpe;
                } its_vinvall_cmd;

                struct {
                        struct its_vpe *vpe;
                        struct its_collection *col;
                        bool valid;
                } its_vmapp_cmd;

                struct {
                        struct its_vpe *vpe;
                        struct its_device *dev;
                        u32 virt_id;
                        u32 event_id;
                        bool db_enabled;
                } its_vmapti_cmd;

                struct {
                        struct its_vpe *vpe;
                        struct its_device *dev;
                        u32 event_id;
                        bool db_enabled;
                } its_vmovi_cmd;

                struct {
                        struct its_vpe *vpe;
                        struct its_collection *col;
                        u16 seq_num;
                        u16 its_list;
                } its_vmovp_cmd;
        };
};

/*
 * The ITS command block, which is what the ITS actually parses.
 */
struct its_cmd_block {
        u64     raw_cmd[4];
};

#define ITS_CMD_QUEUE_SZ                SZ_64K
#define ITS_CMD_QUEUE_NR_ENTRIES        (ITS_CMD_QUEUE_SZ / sizeof(struct its_cmd_block))

typedef struct its_collection *(*its_cmd_builder_t)(struct its_node *,
                                                    struct its_cmd_block *,
                                                    struct its_cmd_desc *);

typedef struct its_vpe *(*its_cmd_vbuilder_t)(struct its_node *,
                                              struct its_cmd_block *,
                                              struct its_cmd_desc *);

static void its_mask_encode(u64 *raw_cmd, u64 val, int h, int l)
{
        u64 mask = GENMASK_ULL(h, l);
        *raw_cmd &= ~mask;
        *raw_cmd |= (val << l) & mask;
}

static void its_encode_cmd(struct its_cmd_block *cmd, u8 cmd_nr)
{
        its_mask_encode(&cmd->raw_cmd[0], cmd_nr, 7, 0);
}

static void its_encode_devid(struct its_cmd_block *cmd, u32 devid)
{
        its_mask_encode(&cmd->raw_cmd[0], devid, 63, 32);
}

static void its_encode_event_id(struct its_cmd_block *cmd, u32 id)
{
        its_mask_encode(&cmd->raw_cmd[1], id, 31, 0);
}

static void its_encode_phys_id(struct its_cmd_block *cmd, u32 phys_id)
{
        its_mask_encode(&cmd->raw_cmd[1], phys_id, 63, 32);
}

static void its_encode_size(struct its_cmd_block *cmd, u8 size)
{
        its_mask_encode(&cmd->raw_cmd[1], size, 4, 0);
}

static void its_encode_itt(struct its_cmd_block *cmd, u64 itt_addr)
{
        its_mask_encode(&cmd->raw_cmd[2], itt_addr >> 8, 51, 8);
}

static void its_encode_valid(struct its_cmd_block *cmd, int valid)
{
        its_mask_encode(&cmd->raw_cmd[2], !!valid, 63, 63);
}

static void its_encode_target(struct its_cmd_block *cmd, u64 target_addr)
{
        its_mask_encode(&cmd->raw_cmd[2], target_addr >> 16, 51, 16);
}

static void its_encode_collection(struct its_cmd_block *cmd, u16 col)
{
        its_mask_encode(&cmd->raw_cmd[2], col, 15, 0);
}

static void its_encode_vpeid(struct its_cmd_block *cmd, u16 vpeid)
{
        its_mask_encode(&cmd->raw_cmd[1], vpeid, 47, 32);
}

static void its_encode_virt_id(struct its_cmd_block *cmd, u32 virt_id)
{
        its_mask_encode(&cmd->raw_cmd[2], virt_id, 31, 0);
}

static void its_encode_db_phys_id(struct its_cmd_block *cmd, u32 db_phys_id)
{
        its_mask_encode(&cmd->raw_cmd[2], db_phys_id, 63, 32);
}

static void its_encode_db_valid(struct its_cmd_block *cmd, bool db_valid)
{
        its_mask_encode(&cmd->raw_cmd[2], db_valid, 0, 0);
}

static void its_encode_seq_num(struct its_cmd_block *cmd, u16 seq_num)
{
        its_mask_encode(&cmd->raw_cmd[0], seq_num, 47, 32);
}

static void its_encode_its_list(struct its_cmd_block *cmd, u16 its_list)
{
        its_mask_encode(&cmd->raw_cmd[1], its_list, 15, 0);
}

static void its_encode_vpt_addr(struct its_cmd_block *cmd, u64 vpt_pa)
{
        its_mask_encode(&cmd->raw_cmd[3], vpt_pa >> 16, 51, 16);
}

static void its_encode_vpt_size(struct its_cmd_block *cmd, u8 vpt_size)
{
        its_mask_encode(&cmd->raw_cmd[3], vpt_size, 4, 0);
}

static inline void its_fixup_cmd(struct its_cmd_block *cmd)
{
        /* Let's fixup BE commands */
        cmd->raw_cmd[0] = cpu_to_le64(cmd->raw_cmd[0]);
        cmd->raw_cmd[1] = cpu_to_le64(cmd->raw_cmd[1]);
        cmd->raw_cmd[2] = cpu_to_le64(cmd->raw_cmd[2]);
        cmd->raw_cmd[3] = cpu_to_le64(cmd->raw_cmd[3]);
}

static struct its_collection *its_build_mapd_cmd(struct its_node *its,
                                                 struct its_cmd_block *cmd,
                                                 struct its_cmd_desc *desc)
{
        unsigned long itt_addr;
        u8 size = ilog2(desc->its_mapd_cmd.dev->nr_ites);

        itt_addr = virt_to_phys(desc->its_mapd_cmd.dev->itt);
        itt_addr = ALIGN(itt_addr, ITS_ITT_ALIGN);

        its_encode_cmd(cmd, GITS_CMD_MAPD);
        its_encode_devid(cmd, desc->its_mapd_cmd.dev->device_id);
        its_encode_size(cmd, size - 1);
        its_encode_itt(cmd, itt_addr);
        its_encode_valid(cmd, desc->its_mapd_cmd.valid);

        its_fixup_cmd(cmd);

        return NULL;
}

static struct its_collection *its_build_mapc_cmd(struct its_node *its,
                                                 struct its_cmd_block *cmd,
                                                 struct its_cmd_desc *desc)
{
        its_encode_cmd(cmd, GITS_CMD_MAPC);
        its_encode_collection(cmd, desc->its_mapc_cmd.col->col_id);
        its_encode_target(cmd, desc->its_mapc_cmd.col->target_address);
        its_encode_valid(cmd, desc->its_mapc_cmd.valid);

        its_fixup_cmd(cmd);

        return desc->its_mapc_cmd.col;
}

static struct its_collection *its_build_mapti_cmd(struct its_node *its,
                                                  struct its_cmd_block *cmd,
                                                  struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_mapti_cmd.dev,
                               desc->its_mapti_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_MAPTI);
        its_encode_devid(cmd, desc->its_mapti_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_mapti_cmd.event_id);
        its_encode_phys_id(cmd, desc->its_mapti_cmd.phys_id);
        its_encode_collection(cmd, col->col_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_movi_cmd(struct its_node *its,
                                                 struct its_cmd_block *cmd,
                                                 struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_movi_cmd.dev,
                               desc->its_movi_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_MOVI);
        its_encode_devid(cmd, desc->its_movi_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_movi_cmd.event_id);
        its_encode_collection(cmd, desc->its_movi_cmd.col->col_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_discard_cmd(struct its_node *its,
                                                    struct its_cmd_block *cmd,
                                                    struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_discard_cmd.dev,
                               desc->its_discard_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_DISCARD);
        its_encode_devid(cmd, desc->its_discard_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_discard_cmd.event_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_inv_cmd(struct its_node *its,
                                                struct its_cmd_block *cmd,
                                                struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_inv_cmd.dev,
                               desc->its_inv_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_INV);
        its_encode_devid(cmd, desc->its_inv_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_inv_cmd.event_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_int_cmd(struct its_node *its,
                                                struct its_cmd_block *cmd,
                                                struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_int_cmd.dev,
                               desc->its_int_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_INT);
        its_encode_devid(cmd, desc->its_int_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_int_cmd.event_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_clear_cmd(struct its_node *its,
                                                  struct its_cmd_block *cmd,
                                                  struct its_cmd_desc *desc)
{
        struct its_collection *col;

        col = dev_event_to_col(desc->its_clear_cmd.dev,
                               desc->its_clear_cmd.event_id);

        its_encode_cmd(cmd, GITS_CMD_CLEAR);
        its_encode_devid(cmd, desc->its_clear_cmd.dev->device_id);
        its_encode_event_id(cmd, desc->its_clear_cmd.event_id);

        its_fixup_cmd(cmd);

        return valid_col(col);
}

static struct its_collection *its_build_invall_cmd(struct its_node *its,
                                                   struct its_cmd_block *cmd,
                                                   struct its_cmd_desc *desc)
{
        its_encode_cmd(cmd, GITS_CMD_INVALL);
        its_encode_collection(cmd, desc->its_mapc_cmd.col->col_id);

        its_fixup_cmd(cmd);

        return NULL;
}

static struct its_vpe *its_build_vinvall_cmd(struct its_node *its,
                                             struct its_cmd_block *cmd,
                                             struct its_cmd_desc *desc)
{
        its_encode_cmd(cmd, GITS_CMD_VINVALL);
        its_encode_vpeid(cmd, desc->its_vinvall_cmd.vpe->vpe_id);

        its_fixup_cmd(cmd);

        return valid_vpe(its, desc->its_vinvall_cmd.vpe);
}

static struct its_vpe *its_build_vmapp_cmd(struct its_node *its,
                                           struct its_cmd_block *cmd,
                                           struct its_cmd_desc *desc)
{
        unsigned long vpt_addr;
        u64 target;

        vpt_addr = virt_to_phys(page_address(desc->its_vmapp_cmd.vpe->vpt_page));
        target = desc->its_vmapp_cmd.col->target_address + its->vlpi_redist_offset;

        its_encode_cmd(cmd, GITS_CMD_VMAPP);
        its_encode_vpeid(cmd, desc->its_vmapp_cmd.vpe->vpe_id);
        its_encode_valid(cmd, desc->its_vmapp_cmd.valid);
        its_encode_target(cmd, target);
        its_encode_vpt_addr(cmd, vpt_addr);
        its_encode_vpt_size(cmd, LPI_NRBITS - 1);

        its_fixup_cmd(cmd);

        return valid_vpe(its, desc->its_vmapp_cmd.vpe);
}

static struct its_vpe *its_build_vmapti_cmd(struct its_node *its,
                                            struct its_cmd_block *cmd,
                                            struct its_cmd_desc *desc)
{
        u32 db;

        if (desc->its_vmapti_cmd.db_enabled)
                db = desc->its_vmapti_cmd.vpe->vpe_db_lpi;
        else
                db = 1023;

        its_encode_cmd(cmd, GITS_CMD_VMAPTI);
        its_encode_devid(cmd, desc->its_vmapti_cmd.dev->device_id);
        its_encode_vpeid(cmd, desc->its_vmapti_cmd.vpe->vpe_id);
        its_encode_event_id(cmd, desc->its_vmapti_cmd.event_id);
        its_encode_db_phys_id(cmd, db);
        its_encode_virt_id(cmd, desc->its_vmapti_cmd.virt_id);

        its_fixup_cmd(cmd);

        return valid_vpe(its, desc->its_vmapti_cmd.vpe);
}

static struct its_vpe *its_build_vmovi_cmd(struct its_node *its,
                                           struct its_cmd_block *cmd,
                                           struct its_cmd_desc *desc)
{
        u32 db;

        if (desc->its_vmovi_cmd.db_enabled)
                db = desc->its_vmovi_cmd.vpe->vpe_db_lpi;
        else
                db = 1023;

        its_encode_cmd(cmd, GITS_CMD_VMOVI);
        its_encode_devid(cmd, desc->its_vmovi_cmd.dev->device_id);
        its_encode_vpeid(cmd, desc->its_vmovi_cmd.vpe->vpe_id);
        its_encode_event_id(cmd, desc->its_vmovi_cmd.event_id);
        its_encode_db_phys_id(cmd, db);
        its_encode_db_valid(cmd, true);

        its_fixup_cmd(cmd);

        return valid_vpe(its, desc->its_vmovi_cmd.vpe);
}

static struct its_vpe *its_build_vmovp_cmd(struct its_node *its,
                                           struct its_cmd_block *cmd,
                                           struct its_cmd_desc *desc)
{
        u64 target;

        target = desc->its_vmovp_cmd.col->target_address + its->vlpi_redist_offset;
        its_encode_cmd(cmd, GITS_CMD_VMOVP);
        its_encode_seq_num(cmd, desc->its_vmovp_cmd.seq_num);
        its_encode_its_list(cmd, desc->its_vmovp_cmd.its_list);
        its_encode_vpeid(cmd, desc->its_vmovp_cmd.vpe->vpe_id);
        its_encode_target(cmd, target);

        its_fixup_cmd(cmd);

        return valid_vpe(its, desc->its_vmovp_cmd.vpe);
}

static u64 its_cmd_ptr_to_offset(struct its_node *its,
                                 struct its_cmd_block *ptr)
{
        return (ptr - its->cmd_base) * sizeof(*ptr);
}

static int its_queue_full(struct its_node *its)
{
        int widx;
        int ridx;

        widx = its->cmd_write - its->cmd_base;
        ridx = readl_relaxed(its->base + GITS_CREADR) / sizeof(struct its_cmd_block);

        /* This is incredibly unlikely to happen, unless the ITS locks up. */
        if (((widx + 1) % ITS_CMD_QUEUE_NR_ENTRIES) == ridx)
                return 1;

        return 0;
}

static struct its_cmd_block *its_allocate_entry(struct its_node *its)
{
        struct its_cmd_block *cmd;
        u32 count = 1000000;    /* 1s! */

        while (its_queue_full(its)) {
                count--;
                if (!count) {
                        pr_err_ratelimited("ITS queue not draining\n");
                        return NULL;
                }
                cpu_relax();
                udelay(1);
        }

        cmd = its->cmd_write++;

        /* Handle queue wrapping */
        if (its->cmd_write == (its->cmd_base + ITS_CMD_QUEUE_NR_ENTRIES))
                its->cmd_write = its->cmd_base;

        /* Clear command  */
        cmd->raw_cmd[0] = 0;
        cmd->raw_cmd[1] = 0;
        cmd->raw_cmd[2] = 0;
        cmd->raw_cmd[3] = 0;

        return cmd;
}

static struct its_cmd_block *its_post_commands(struct its_node *its)
{
        u64 wr = its_cmd_ptr_to_offset(its, its->cmd_write);

        writel_relaxed(wr, its->base + GITS_CWRITER);

        return its->cmd_write;
}

static void its_flush_cmd(struct its_node *its, struct its_cmd_block *cmd)
{
        /*
         * Make sure the commands written to memory are observable by
         * the ITS.
         */
        if (its->flags & ITS_FLAGS_CMDQ_NEEDS_FLUSHING)
                gic_flush_dcache_to_poc(cmd, sizeof(*cmd));
        else
                dsb(ishst);
}

static int its_wait_for_range_completion(struct its_node *its,
                                         u64    prev_idx,
                                         struct its_cmd_block *to)
{
        u64 rd_idx, to_idx, linear_idx;
        u32 count = 1000000;    /* 1s! */

        /* Linearize to_idx if the command set has wrapped around */
        to_idx = its_cmd_ptr_to_offset(its, to);
        if (to_idx < prev_idx)
                to_idx += ITS_CMD_QUEUE_SZ;

        linear_idx = prev_idx;

        while (1) {
                s64 delta;

                rd_idx = readl_relaxed(its->base + GITS_CREADR);

                /*
                 * Compute the read pointer progress, taking the
                 * potential wrap-around into account.
                 */
                delta = rd_idx - prev_idx;
                if (rd_idx < prev_idx)
                        delta += ITS_CMD_QUEUE_SZ;

                linear_idx += delta;
                if (linear_idx >= to_idx)
                        break;

                count--;
                if (!count) {
                        pr_err_ratelimited("ITS queue timeout (%llu %llu)\n",
                                           to_idx, linear_idx);
                        return -1;
                }
                prev_idx = rd_idx;
                cpu_relax();
                udelay(1);
        }

        return 0;
}

/* Warning, macro hell follows */
#define BUILD_SINGLE_CMD_FUNC(name, buildtype, synctype, buildfn)       \
void name(struct its_node *its,                                         \
          buildtype builder,                                            \
          struct its_cmd_desc *desc)                                    \
{                                                                       \
        struct its_cmd_block *cmd, *sync_cmd, *next_cmd;                \
        synctype *sync_obj;                                             \
        unsigned long flags;                                            \
        u64 rd_idx;                                                     \
                                                                        \
        raw_spin_lock_irqsave(&its->lock, flags);                       \
                                                                        \
        cmd = its_allocate_entry(its);                                  \
        if (!cmd) {             /* We're soooooo screewed... */         \
                raw_spin_unlock_irqrestore(&its->lock, flags);          \
                return;                                                 \
        }                                                               \
        sync_obj = builder(its, cmd, desc);                             \
        its_flush_cmd(its, cmd);                                        \
                                                                        \
        if (sync_obj) {                                                 \
                sync_cmd = its_allocate_entry(its);                     \
                if (!sync_cmd)                                          \
                        goto post;                                      \
                                                                        \
                buildfn(its, sync_cmd, sync_obj);                       \
                its_flush_cmd(its, sync_cmd);                           \
        }                                                               \
                                                                        \
post:                                                                   \
        rd_idx = readl_relaxed(its->base + GITS_CREADR);                \
        next_cmd = its_post_commands(its);                              \
        raw_spin_unlock_irqrestore(&its->lock, flags);                  \
                                                                        \
        if (its_wait_for_range_completion(its, rd_idx, next_cmd))       \
                pr_err_ratelimited("ITS cmd %ps failed\n", builder);    \
}

static void its_build_sync_cmd(struct its_node *its,
                               struct its_cmd_block *sync_cmd,
                               struct its_collection *sync_col)
{
        its_encode_cmd(sync_cmd, GITS_CMD_SYNC);
        its_encode_target(sync_cmd, sync_col->target_address);

        its_fixup_cmd(sync_cmd);
}

static BUILD_SINGLE_CMD_FUNC(its_send_single_command, its_cmd_builder_t,
                             struct its_collection, its_build_sync_cmd)

static void its_build_vsync_cmd(struct its_node *its,
                                struct its_cmd_block *sync_cmd,
                                struct its_vpe *sync_vpe)
{
        its_encode_cmd(sync_cmd, GITS_CMD_VSYNC);
        its_encode_vpeid(sync_cmd, sync_vpe->vpe_id);

        its_fixup_cmd(sync_cmd);
}

static BUILD_SINGLE_CMD_FUNC(its_send_single_vcommand, its_cmd_vbuilder_t,
                             struct its_vpe, its_build_vsync_cmd)

static void its_send_int(struct its_device *dev, u32 event_id)
{
        struct its_cmd_desc desc;

        desc.its_int_cmd.dev = dev;
        desc.its_int_cmd.event_id = event_id;

        its_send_single_command(dev->its, its_build_int_cmd, &desc);
}

static void its_send_clear(struct its_device *dev, u32 event_id)
{
        struct its_cmd_desc desc;

        desc.its_clear_cmd.dev = dev;
        desc.its_clear_cmd.event_id = event_id;

        its_send_single_command(dev->its, its_build_clear_cmd, &desc);
}

static void its_send_inv(struct its_device *dev, u32 event_id)
{
        struct its_cmd_desc desc;

        desc.its_inv_cmd.dev = dev;
        desc.its_inv_cmd.event_id = event_id;

        its_send_single_command(dev->its, its_build_inv_cmd, &desc);
}

static void its_send_mapd(struct its_device *dev, int valid)
{
        struct its_cmd_desc desc;

        desc.its_mapd_cmd.dev = dev;
        desc.its_mapd_cmd.valid = !!valid;

        its_send_single_command(dev->its, its_build_mapd_cmd, &desc);
}

static void its_send_mapc(struct its_node *its, struct its_collection *col,
                          int valid)
{
        struct its_cmd_desc desc;

        desc.its_mapc_cmd.col = col;
        desc.its_mapc_cmd.valid = !!valid;

        its_send_single_command(its, its_build_mapc_cmd, &desc);
}

static void its_send_mapti(struct its_device *dev, u32 irq_id, u32 id)
{
        struct its_cmd_desc desc;

        desc.its_mapti_cmd.dev = dev;
        desc.its_mapti_cmd.phys_id = irq_id;
        desc.its_mapti_cmd.event_id = id;

        its_send_single_command(dev->its, its_build_mapti_cmd, &desc);
}

static void its_send_movi(struct its_device *dev,
                          struct its_collection *col, u32 id)
{
        struct its_cmd_desc desc;

        desc.its_movi_cmd.dev = dev;
        desc.its_movi_cmd.col = col;
        desc.its_movi_cmd.event_id = id;

        its_send_single_command(dev->its, its_build_movi_cmd, &desc);
}

static void its_send_discard(struct its_device *dev, u32 id)
{
        struct its_cmd_desc desc;

        desc.its_discard_cmd.dev = dev;
        desc.its_discard_cmd.event_id = id;

        its_send_single_command(dev->its, its_build_discard_cmd, &desc);
}

static void its_send_invall(struct its_node *its, struct its_collection *col)
{
        struct its_cmd_desc desc;

        desc.its_invall_cmd.col = col;

        its_send_single_command(its, its_build_invall_cmd, &desc);
}

static void its_send_vmapti(struct its_device *dev, u32 id)
{
        struct its_vlpi_map *map = &dev->event_map.vlpi_maps[id];
        struct its_cmd_desc desc;

        desc.its_vmapti_cmd.vpe = map->vpe;
        desc.its_vmapti_cmd.dev = dev;
        desc.its_vmapti_cmd.virt_id = map->vintid;
        desc.its_vmapti_cmd.event_id = id;
        desc.its_vmapti_cmd.db_enabled = map->db_enabled;

        its_send_single_vcommand(dev->its, its_build_vmapti_cmd, &desc);
}

static void its_send_vmovi(struct its_device *dev, u32 id)
{
        struct its_vlpi_map *map = &dev->event_map.vlpi_maps[id];
        struct its_cmd_desc desc;

        desc.its_vmovi_cmd.vpe = map->vpe;
        desc.its_vmovi_cmd.dev = dev;
        desc.its_vmovi_cmd.event_id = id;
        desc.its_vmovi_cmd.db_enabled = map->db_enabled;

        its_send_single_vcommand(dev->its, its_build_vmovi_cmd, &desc);
}

static void its_send_vmapp(struct its_node *its,
                           struct its_vpe *vpe, bool valid)
{
        struct its_cmd_desc desc;

        desc.its_vmapp_cmd.vpe = vpe;
        desc.its_vmapp_cmd.valid = valid;
        desc.its_vmapp_cmd.col = &its->collections[vpe->col_idx];

        its_send_single_vcommand(its, its_build_vmapp_cmd, &desc);
}

static void its_send_vmovp(struct its_vpe *vpe)
{
        struct its_cmd_desc desc;
        struct its_node *its;
        unsigned long flags;
        int col_id = vpe->col_idx;

        desc.its_vmovp_cmd.vpe = vpe;
        desc.its_vmovp_cmd.its_list = (u16)its_list_map;

        if (!its_list_map) {
                its = list_first_entry(&its_nodes, struct its_node, entry);
                desc.its_vmovp_cmd.seq_num = 0;
                desc.its_vmovp_cmd.col = &its->collections[col_id];
                its_send_single_vcommand(its, its_build_vmovp_cmd, &desc);
                return;
        }

        /*
         * Yet another marvel of the architecture. If using the
         * its_list "feature", we need to make sure that all ITSs
         * receive all VMOVP commands in the same order. The only way
         * to guarantee this is to make vmovp a serialization point.
         *

         * Wall <-- Head.
         */
        raw_spin_lock_irqsave(&vmovp_lock, flags);

        desc.its_vmovp_cmd.seq_num = vmovp_seq_num++;

        /* Emit VMOVPs */
        list_for_each_entry(its, &its_nodes, entry) {
                if (!its->is_v4)
                        continue;

                if (!vpe->its_vm->vlpi_count[its->list_nr])
                        continue;

                desc.its_vmovp_cmd.col = &its->collections[col_id];
                its_send_single_vcommand(its, its_build_vmovp_cmd, &desc);
        }

        raw_spin_unlock_irqrestore(&vmovp_lock, flags);
}

static void its_send_vinvall(struct its_node *its, struct its_vpe *vpe)
{
        struct its_cmd_desc desc;

        desc.its_vinvall_cmd.vpe = vpe;
        its_send_single_vcommand(its, its_build_vinvall_cmd, &desc);
}

/*
 * irqchip functions - assumes MSI, mostly.
 */

static inline u32 its_get_event_id(struct irq_data *d)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        return d->hwirq - its_dev->event_map.lpi_base;
}

static void lpi_write_config(struct irq_data *d, u8 clr, u8 set)
{
        irq_hw_number_t hwirq;
        void *va;
        u8 *cfg;

        if (irqd_is_forwarded_to_vcpu(d)) {
                struct its_device *its_dev = irq_data_get_irq_chip_data(d);
                u32 event = its_get_event_id(d);
                struct its_vlpi_map *map;

                va = page_address(its_dev->event_map.vm->vprop_page);
                map = &its_dev->event_map.vlpi_maps[event];
                hwirq = map->vintid;

                /* Remember the updated property */
                map->properties &= ~clr;
                map->properties |= set | LPI_PROP_GROUP1;
        } else {
                va = gic_rdists->prop_table_va;
                hwirq = d->hwirq;
        }

        cfg = va + hwirq - 8192;
        *cfg &= ~clr;
        *cfg |= set | LPI_PROP_GROUP1;

        /*
         * Make the above write visible to the redistributors.
         * And yes, we're flushing exactly: One. Single. Byte.
         * Humpf...
         */
        if (gic_rdists->flags & RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING)
                gic_flush_dcache_to_poc(cfg, sizeof(*cfg));
        else
                dsb(ishst);
}

static void lpi_update_config(struct irq_data *d, u8 clr, u8 set)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);

        lpi_write_config(d, clr, set);
        its_send_inv(its_dev, its_get_event_id(d));
}

static void its_vlpi_set_doorbell(struct irq_data *d, bool enable)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);

        if (its_dev->event_map.vlpi_maps[event].db_enabled == enable)
                return;

        its_dev->event_map.vlpi_maps[event].db_enabled = enable;

        /*
         * More fun with the architecture:
         *
         * Ideally, we'd issue a VMAPTI to set the doorbell to its LPI
         * value or to 1023, depending on the enable bit. But that
         * would be issueing a mapping for an /existing/ DevID+EventID
         * pair, which is UNPREDICTABLE. Instead, let's issue a VMOVI
         * to the /same/ vPE, using this opportunity to adjust the
         * doorbell. Mouahahahaha. We loves it, Precious.
         */
        its_send_vmovi(its_dev, event);
}

static void its_mask_irq(struct irq_data *d)
{
        if (irqd_is_forwarded_to_vcpu(d))
                its_vlpi_set_doorbell(d, false);

        lpi_update_config(d, LPI_PROP_ENABLED, 0);
}

static void its_unmask_irq(struct irq_data *d)
{
        if (irqd_is_forwarded_to_vcpu(d))
                its_vlpi_set_doorbell(d, true);

        lpi_update_config(d, 0, LPI_PROP_ENABLED);
}

static int its_set_affinity(struct irq_data *d, const struct cpumask *mask_val,
                            bool force)
{
        unsigned int cpu;
        const struct cpumask *cpu_mask = cpu_online_mask;
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        struct its_collection *target_col;
        u32 id = its_get_event_id(d);

        /* A forwarded interrupt should use irq_set_vcpu_affinity */
        if (irqd_is_forwarded_to_vcpu(d))
                return -EINVAL;

       /* lpi cannot be routed to a redistributor that is on a foreign node */
        if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) {
                if (its_dev->its->numa_node >= 0) {
                        cpu_mask = cpumask_of_node(its_dev->its->numa_node);
                        if (!cpumask_intersects(mask_val, cpu_mask))
                                return -EINVAL;
                }
        }

        cpu = cpumask_any_and(mask_val, cpu_mask);

        if (cpu >= nr_cpu_ids)
                return -EINVAL;

        /* don't set the affinity when the target cpu is same as current one */
        if (cpu != its_dev->event_map.col_map[id]) {
                target_col = &its_dev->its->collections[cpu];
                its_send_movi(its_dev, target_col, id);
                its_dev->event_map.col_map[id] = cpu;
                irq_data_update_effective_affinity(d, cpumask_of(cpu));
        }

        return IRQ_SET_MASK_OK_DONE;
}

static u64 its_irq_get_msi_base(struct its_device *its_dev)
{
        struct its_node *its = its_dev->its;

        return its->phys_base + GITS_TRANSLATER;
}

static void its_irq_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        struct its_node *its;
        u64 addr;

        its = its_dev->its;
        addr = its->get_msi_base(its_dev);

        msg->address_lo         = lower_32_bits(addr);
        msg->address_hi         = upper_32_bits(addr);
        msg->data               = its_get_event_id(d);

        iommu_dma_compose_msi_msg(irq_data_get_msi_desc(d), msg);
}

static int its_irq_set_irqchip_state(struct irq_data *d,
                                     enum irqchip_irq_state which,
                                     bool state)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);

        if (which != IRQCHIP_STATE_PENDING)
                return -EINVAL;

        if (state)
                its_send_int(its_dev, event);
        else
                its_send_clear(its_dev, event);

        return 0;
}

static void its_map_vm(struct its_node *its, struct its_vm *vm)
{
        unsigned long flags;

        /* Not using the ITS list? Everything is always mapped. */
        if (!its_list_map)
                return;

        raw_spin_lock_irqsave(&vmovp_lock, flags);

        /*
         * If the VM wasn't mapped yet, iterate over the vpes and get
         * them mapped now.
         */
        vm->vlpi_count[its->list_nr]++;

        if (vm->vlpi_count[its->list_nr] == 1) {
                int i;

                for (i = 0; i < vm->nr_vpes; i++) {
                        struct its_vpe *vpe = vm->vpes[i];
                        struct irq_data *d = irq_get_irq_data(vpe->irq);

                        /* Map the VPE to the first possible CPU */
                        vpe->col_idx = cpumask_first(cpu_online_mask);
                        its_send_vmapp(its, vpe, true);
                        its_send_vinvall(its, vpe);
                        irq_data_update_effective_affinity(d, cpumask_of(vpe->col_idx));
                }
        }

        raw_spin_unlock_irqrestore(&vmovp_lock, flags);
}

static void its_unmap_vm(struct its_node *its, struct its_vm *vm)
{
        unsigned long flags;

        /* Not using the ITS list? Everything is always mapped. */
        if (!its_list_map)
                return;

        raw_spin_lock_irqsave(&vmovp_lock, flags);

        if (!--vm->vlpi_count[its->list_nr]) {
                int i;

                for (i = 0; i < vm->nr_vpes; i++)
                        its_send_vmapp(its, vm->vpes[i], false);
        }

        raw_spin_unlock_irqrestore(&vmovp_lock, flags);
}

static int its_vlpi_map(struct irq_data *d, struct its_cmd_info *info)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);
        int ret = 0;

        if (!info->map)
                return -EINVAL;

        mutex_lock(&its_dev->event_map.vlpi_lock);

        if (!its_dev->event_map.vm) {
                struct its_vlpi_map *maps;

                maps = kcalloc(its_dev->event_map.nr_lpis, sizeof(*maps),
                               GFP_KERNEL);
                if (!maps) {
                        ret = -ENOMEM;
                        goto out;
                }

                its_dev->event_map.vm = info->map->vm;
                its_dev->event_map.vlpi_maps = maps;
        } else if (its_dev->event_map.vm != info->map->vm) {
                ret = -EINVAL;
                goto out;
        }

        /* Get our private copy of the mapping information */
        its_dev->event_map.vlpi_maps[event] = *info->map;

        if (irqd_is_forwarded_to_vcpu(d)) {
                /* Already mapped, move it around */
                its_send_vmovi(its_dev, event);
        } else {
                /* Ensure all the VPEs are mapped on this ITS */
                its_map_vm(its_dev->its, info->map->vm);

                /*
                 * Flag the interrupt as forwarded so that we can
                 * start poking the virtual property table.
                 */
                irqd_set_forwarded_to_vcpu(d);

                /* Write out the property to the prop table */
                lpi_write_config(d, 0xff, info->map->properties);

                /* Drop the physical mapping */
                its_send_discard(its_dev, event);

                /* and install the virtual one */
                its_send_vmapti(its_dev, event);

                /* Increment the number of VLPIs */
                its_dev->event_map.nr_vlpis++;
        }

out:
        mutex_unlock(&its_dev->event_map.vlpi_lock);
        return ret;
}

static int its_vlpi_get(struct irq_data *d, struct its_cmd_info *info)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);
        int ret = 0;

        mutex_lock(&its_dev->event_map.vlpi_lock);

        if (!its_dev->event_map.vm ||
            !its_dev->event_map.vlpi_maps[event].vm) {
                ret = -EINVAL;
                goto out;
        }

        /* Copy our mapping information to the incoming request */
        *info->map = its_dev->event_map.vlpi_maps[event];

out:
        mutex_unlock(&its_dev->event_map.vlpi_lock);
        return ret;
}

static int its_vlpi_unmap(struct irq_data *d)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);
        int ret = 0;

        mutex_lock(&its_dev->event_map.vlpi_lock);

        if (!its_dev->event_map.vm || !irqd_is_forwarded_to_vcpu(d)) {
                ret = -EINVAL;
                goto out;
        }

        /* Drop the virtual mapping */
        its_send_discard(its_dev, event);

        /* and restore the physical one */
        irqd_clr_forwarded_to_vcpu(d);
        its_send_mapti(its_dev, d->hwirq, event);
        lpi_update_config(d, 0xff, (LPI_PROP_DEFAULT_PRIO |
                                    LPI_PROP_ENABLED |
                                    LPI_PROP_GROUP1));

        /* Potentially unmap the VM from this ITS */
        its_unmap_vm(its_dev->its, its_dev->event_map.vm);

        /*
         * Drop the refcount and make the device available again if
         * this was the last VLPI.
         */
        if (!--its_dev->event_map.nr_vlpis) {
                its_dev->event_map.vm = NULL;
                kfree(its_dev->event_map.vlpi_maps);
        }

out:
        mutex_unlock(&its_dev->event_map.vlpi_lock);
        return ret;
}

static int its_vlpi_prop_update(struct irq_data *d, struct its_cmd_info *info)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);

        if (!its_dev->event_map.vm || !irqd_is_forwarded_to_vcpu(d))
                return -EINVAL;

        if (info->cmd_type == PROP_UPDATE_AND_INV_VLPI)
                lpi_update_config(d, 0xff, info->config);
        else
                lpi_write_config(d, 0xff, info->config);
        its_vlpi_set_doorbell(d, !!(info->config & LPI_PROP_ENABLED));

        return 0;
}

static int its_irq_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        struct its_cmd_info *info = vcpu_info;

        /* Need a v4 ITS */
        if (!its_dev->its->is_v4)
                return -EINVAL;

        /* Unmap request? */
        if (!info)
                return its_vlpi_unmap(d);

        switch (info->cmd_type) {
        case MAP_VLPI:
                return its_vlpi_map(d, info);

        case GET_VLPI:
                return its_vlpi_get(d, info);

        case PROP_UPDATE_VLPI:
        case PROP_UPDATE_AND_INV_VLPI:
                return its_vlpi_prop_update(d, info);

        default:
                return -EINVAL;
        }
}

static struct irq_chip its_irq_chip = {
        .name                   = "ITS",
        .irq_mask               = its_mask_irq,
        .irq_unmask             = its_unmask_irq,
        .irq_eoi                = irq_chip_eoi_parent,
        .irq_set_affinity       = its_set_affinity,
        .irq_compose_msi_msg    = its_irq_compose_msi_msg,
        .irq_set_irqchip_state  = its_irq_set_irqchip_state,
        .irq_set_vcpu_affinity  = its_irq_set_vcpu_affinity,
};


/*
 * How we allocate LPIs:
 *
 * lpi_range_list contains ranges of LPIs that are to available to
 * allocate from. To allocate LPIs, just pick the first range that
 * fits the required allocation, and reduce it by the required
 * amount. Once empty, remove the range from the list.
 *
 * To free a range of LPIs, add a free range to the list, sort it and
 * merge the result if the new range happens to be adjacent to an
 * already free block.
 *
 * The consequence of the above is that allocation is cost is low, but
 * freeing is expensive. We assumes that freeing rarely occurs.
 */
#define ITS_MAX_LPI_NRBITS      16 /* 64K LPIs */

static DEFINE_MUTEX(lpi_range_lock);
static LIST_HEAD(lpi_range_list);

struct lpi_range {
        struct list_head        entry;
        u32                     base_id;
        u32                     span;
};

static struct lpi_range *mk_lpi_range(u32 base, u32 span)
{
        struct lpi_range *range;

        range = kmalloc(sizeof(*range), GFP_KERNEL);
        if (range) {
                range->base_id = base;
                range->span = span;
        }

        return range;
}

static int alloc_lpi_range(u32 nr_lpis, u32 *base)
{
        struct lpi_range *range, *tmp;
        int err = -ENOSPC;

        mutex_lock(&lpi_range_lock);

        list_for_each_entry_safe(range, tmp, &lpi_range_list, entry) {
                if (range->span >= nr_lpis) {
                        *base = range->base_id;
                        range->base_id += nr_lpis;
                        range->span -= nr_lpis;

                        if (range->span == 0) {
                                list_del(&range->entry);
                                kfree(range);
                        }

                        err = 0;
                        break;
                }
        }

        mutex_unlock(&lpi_range_lock);

        pr_debug("ITS: alloc %u:%u\n", *base, nr_lpis);
        return err;
}

static void merge_lpi_ranges(struct lpi_range *a, struct lpi_range *b)
{
        if (&a->entry == &lpi_range_list || &b->entry == &lpi_range_list)
                return;
        if (a->base_id + a->span != b->base_id)
                return;
        b->base_id = a->base_id;
        b->span += a->span;
        list_del(&a->entry);
        kfree(a);
}

static int free_lpi_range(u32 base, u32 nr_lpis)
{
        struct lpi_range *new, *old;

        new = mk_lpi_range(base, nr_lpis);
        if (!new)
                return -ENOMEM;

        mutex_lock(&lpi_range_lock);

        list_for_each_entry_reverse(old, &lpi_range_list, entry) {
                if (old->base_id < base)
                        break;
        }
        /*
         * old is the last element with ->base_id smaller than base,
         * so new goes right after it. If there are no elements with
         * ->base_id smaller than base, &old->entry ends up pointing
         * at the head of the list, and inserting new it the start of
         * the list is the right thing to do in that case as well.
         */
        list_add(&new->entry, &old->entry);
        /*
         * Now check if we can merge with the preceding and/or
         * following ranges.
         */
        merge_lpi_ranges(old, new);
        merge_lpi_ranges(new, list_next_entry(new, entry));

        mutex_unlock(&lpi_range_lock);
        return 0;
}

static int __init its_lpi_init(u32 id_bits)
{
        u32 lpis = (1UL << id_bits) - 8192;
        u32 numlpis;
        int err;

        numlpis = 1UL << GICD_TYPER_NUM_LPIS(gic_rdists->gicd_typer);

        if (numlpis > 2 && !WARN_ON(numlpis > lpis)) {
                lpis = numlpis;
                pr_info("ITS: Using hypervisor restricted LPI range [%u]\n",
                        lpis);
        }

        /*
         * Initializing the allocator is just the same as freeing the
         * full range of LPIs.
         */
        err = free_lpi_range(8192, lpis);
        pr_debug("ITS: Allocator initialized for %u LPIs\n", lpis);
        return err;
}

static unsigned long *its_lpi_alloc(int nr_irqs, u32 *base, int *nr_ids)
{
        unsigned long *bitmap = NULL;
        int err = 0;

        do {
                err = alloc_lpi_range(nr_irqs, base);
                if (!err)
                        break;

                nr_irqs /= 2;
        } while (nr_irqs > 0);

        if (!nr_irqs)
                err = -ENOSPC;

        if (err)
                goto out;

        bitmap = kcalloc(BITS_TO_LONGS(nr_irqs), sizeof (long), GFP_ATOMIC);
        if (!bitmap)
                goto out;

        *nr_ids = nr_irqs;

out:
        if (!bitmap)
                *base = *nr_ids = 0;

        return bitmap;
}

static void its_lpi_free(unsigned long *bitmap, u32 base, u32 nr_ids)
{
        WARN_ON(free_lpi_range(base, nr_ids));
        kfree(bitmap);
}

static void gic_reset_prop_table(void *va)
{
        /* Priority 0xa0, Group-1, disabled */
        memset(va, LPI_PROP_DEFAULT_PRIO | LPI_PROP_GROUP1, LPI_PROPBASE_SZ);

        /* Make sure the GIC will observe the written configuration */
        gic_flush_dcache_to_poc(va, LPI_PROPBASE_SZ);
}

static struct page *its_allocate_prop_table(gfp_t gfp_flags)
{
        struct page *prop_page;

        prop_page = alloc_pages(gfp_flags, get_order(LPI_PROPBASE_SZ));
        if (!prop_page)
                return NULL;

        gic_reset_prop_table(page_address(prop_page));

        return prop_page;
}

static void its_free_prop_table(struct page *prop_page)
{
        free_pages((unsigned long)page_address(prop_page),
                   get_order(LPI_PROPBASE_SZ));
}

static bool gic_check_reserved_range(phys_addr_t addr, unsigned long size)
{
        phys_addr_t start, end, addr_end;
        u64 i;

        /*
         * We don't bother checking for a kdump kernel as by
         * construction, the LPI tables are out of this kernel's
         * memory map.
         */
        if (is_kdump_kernel())
                return true;

        addr_end = addr + size - 1;

        for_each_reserved_mem_region(i, &start, &end) {
                if (addr >= start && addr_end <= end)
                        return true;
        }

        /* Not found, not a good sign... */
        pr_warn("GICv3: Expected reserved range [%pa:%pa], not found\n",
                &addr, &addr_end);
        add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
        return false;
}

static int gic_reserve_range(phys_addr_t addr, unsigned long size)
{
        if (efi_enabled(EFI_CONFIG_TABLES))
                return efi_mem_reserve_persistent(addr, size);

        return 0;
}

static int __init its_setup_lpi_prop_table(void)
{
        if (gic_rdists->flags & RDIST_FLAGS_RD_TABLES_PREALLOCATED) {
                u64 val;

                val = gicr_read_propbaser(gic_data_rdist_rd_base() + GICR_PROPBASER);
                lpi_id_bits = (val & GICR_PROPBASER_IDBITS_MASK) + 1;

                gic_rdists->prop_table_pa = val & GENMASK_ULL(51, 12);
                gic_rdists->prop_table_va = memremap(gic_rdists->prop_table_pa,
                                                     LPI_PROPBASE_SZ,
                                                     MEMREMAP_WB);
                gic_reset_prop_table(gic_rdists->prop_table_va);
        } else {
                struct page *page;

                lpi_id_bits = min_t(u32,
                                    GICD_TYPER_ID_BITS(gic_rdists->gicd_typer),
                                    ITS_MAX_LPI_NRBITS);
                page = its_allocate_prop_table(GFP_NOWAIT);
                if (!page) {
                        pr_err("Failed to allocate PROPBASE\n");
                        return -ENOMEM;
                }

                gic_rdists->prop_table_pa = page_to_phys(page);
                gic_rdists->prop_table_va = page_address(page);
                WARN_ON(gic_reserve_range(gic_rdists->prop_table_pa,
                                          LPI_PROPBASE_SZ));
        }

        pr_info("GICv3: using LPI property table @%pa\n",
                &gic_rdists->prop_table_pa);

        return its_lpi_init(lpi_id_bits);
}

static const char *its_base_type_string[] = {
        [GITS_BASER_TYPE_DEVICE]        = "Devices",
        [GITS_BASER_TYPE_VCPU]          = "Virtual CPUs",
        [GITS_BASER_TYPE_RESERVED3]     = "Reserved (3)",
        [GITS_BASER_TYPE_COLLECTION]    = "Interrupt Collections",
        [GITS_BASER_TYPE_RESERVED5]     = "Reserved (5)",
        [GITS_BASER_TYPE_RESERVED6]     = "Reserved (6)",
        [GITS_BASER_TYPE_RESERVED7]     = "Reserved (7)",
};

static u64 its_read_baser(struct its_node *its, struct its_baser *baser)
{
        u32 idx = baser - its->tables;

        return gits_read_baser(its->base + GITS_BASER + (idx << 3));
}

static void its_write_baser(struct its_node *its, struct its_baser *baser,
                            u64 val)
{
        u32 idx = baser - its->tables;

        gits_write_baser(val, its->base + GITS_BASER + (idx << 3));
        baser->val = its_read_baser(its, baser);
}

static int its_setup_baser(struct its_node *its, struct its_baser *baser,
                           u64 cache, u64 shr, u32 psz, u32 order,
                           bool indirect)
{
        u64 val = its_read_baser(its, baser);
        u64 esz = GITS_BASER_ENTRY_SIZE(val);
        u64 type = GITS_BASER_TYPE(val);
        u64 baser_phys, tmp;
        u32 alloc_pages;
        struct page *page;
        void *base;

retry_alloc_baser:
        alloc_pages = (PAGE_ORDER_TO_SIZE(order) / psz);
        if (alloc_pages > GITS_BASER_PAGES_MAX) {
                pr_warn("ITS@%pa: %s too large, reduce ITS pages %u->%u\n",
                        &its->phys_base, its_base_type_string[type],
                        alloc_pages, GITS_BASER_PAGES_MAX);
                alloc_pages = GITS_BASER_PAGES_MAX;
                order = get_order(GITS_BASER_PAGES_MAX * psz);
        }

        page = alloc_pages_node(its->numa_node, GFP_KERNEL | __GFP_ZERO, order);
        if (!page)
                return -ENOMEM;

        base = (void *)page_address(page);
        baser_phys = virt_to_phys(base);

        /* Check if the physical address of the memory is above 48bits */
        if (IS_ENABLED(CONFIG_ARM64_64K_PAGES) && (baser_phys >> 48)) {

                /* 52bit PA is supported only when PageSize=64K */
                if (psz != SZ_64K) {
                        pr_err("ITS: no 52bit PA support when psz=%d\n", psz);
                        free_pages((unsigned long)base, order);
                        return -ENXIO;
                }

                /* Convert 52bit PA to 48bit field */
                baser_phys = GITS_BASER_PHYS_52_to_48(baser_phys);
        }

retry_baser:
        val = (baser_phys                                        |
                (type << GITS_BASER_TYPE_SHIFT)                  |
                ((esz - 1) << GITS_BASER_ENTRY_SIZE_SHIFT)       |
                ((alloc_pages - 1) << GITS_BASER_PAGES_SHIFT)    |
                cache                                            |
                shr                                              |
                GITS_BASER_VALID);

        val |=  indirect ? GITS_BASER_INDIRECT : 0x0;

        switch (psz) {
        case SZ_4K:
                val |= GITS_BASER_PAGE_SIZE_4K;
                break;
        case SZ_16K:
                val |= GITS_BASER_PAGE_SIZE_16K;
                break;
        case SZ_64K:
                val |= GITS_BASER_PAGE_SIZE_64K;
                break;
        }

        its_write_baser(its, baser, val);
        tmp = baser->val;

        if ((val ^ tmp) & GITS_BASER_SHAREABILITY_MASK) {
                /*
                 * Shareability didn't stick. Just use
                 * whatever the read reported, which is likely
                 * to be the only thing this redistributor
                 * supports. If that's zero, make it
                 * non-cacheable as well.
                 */
                shr = tmp & GITS_BASER_SHAREABILITY_MASK;
                if (!shr) {
                        cache = GITS_BASER_nC;
                        gic_flush_dcache_to_poc(base, PAGE_ORDER_TO_SIZE(order));
                }
                goto retry_baser;
        }

        if ((val ^ tmp) & GITS_BASER_PAGE_SIZE_MASK) {
                /*
                 * Page size didn't stick. Let's try a smaller
                 * size and retry. If we reach 4K, then
                 * something is horribly wrong...
                 */
                free_pages((unsigned long)base, order);
                baser->base = NULL;

                switch (psz) {
                case SZ_16K:
                        psz = SZ_4K;
                        goto retry_alloc_baser;
                case SZ_64K:
                        psz = SZ_16K;
                        goto retry_alloc_baser;
                }
        }

        if (val != tmp) {
                pr_err("ITS@%pa: %s doesn't stick: %llx %llx\n",
                       &its->phys_base, its_base_type_string[type],
                       val, tmp);
                free_pages((unsigned long)base, order);
                return -ENXIO;
        }

        baser->order = order;
        baser->base = base;
        baser->psz = psz;
        tmp = indirect ? GITS_LVL1_ENTRY_SIZE : esz;

        pr_info("ITS@%pa: allocated %d %s @%lx (%s, esz %d, psz %dK, shr %d)\n",
                &its->phys_base, (int)(PAGE_ORDER_TO_SIZE(order) / (int)tmp),
                its_base_type_string[type],
                (unsigned long)virt_to_phys(base),
                indirect ? "indirect" : "flat", (int)esz,
                psz / SZ_1K, (int)shr >> GITS_BASER_SHAREABILITY_SHIFT);

        return 0;
}

static bool its_parse_indirect_baser(struct its_node *its,
                                     struct its_baser *baser,
                                     u32 psz, u32 *order, u32 ids)
{
        u64 tmp = its_read_baser(its, baser);
        u64 type = GITS_BASER_TYPE(tmp);
        u64 esz = GITS_BASER_ENTRY_SIZE(tmp);
        u64 val = GITS_BASER_InnerShareable | GITS_BASER_RaWaWb;
        u32 new_order = *order;
        bool indirect = false;

        /* No need to enable Indirection if memory requirement < (psz*2)bytes */
        if ((esz << ids) > (psz * 2)) {
                /*
                 * Find out whether hw supports a single or two-level table by
                 * table by reading bit at offset '62' after writing '1' to it.
                 */
                its_write_baser(its, baser, val | GITS_BASER_INDIRECT);
                indirect = !!(baser->val & GITS_BASER_INDIRECT);

                if (indirect) {
                        /*
                         * The size of the lvl2 table is equal to ITS page size
                         * which is 'psz'. For computing lvl1 table size,
                         * subtract ID bits that sparse lvl2 table from 'ids'
                         * which is reported by ITS hardware times lvl1 table
                         * entry size.
                         */
                        ids -= ilog2(psz / (int)esz);
                        esz = GITS_LVL1_ENTRY_SIZE;
                }
        }

        /*
         * Allocate as many entries as required to fit the
         * range of device IDs that the ITS can grok... The ID
         * space being incredibly sparse, this results in a
         * massive waste of memory if two-level device table
         * feature is not supported by hardware.
         */
        new_order = max_t(u32, get_order(esz << ids), new_order);
        if (new_order >= MAX_ORDER) {
                new_order = MAX_ORDER - 1;
                ids = ilog2(PAGE_ORDER_TO_SIZE(new_order) / (int)esz);
                pr_warn("ITS@%pa: %s Table too large, reduce ids %u->%u\n",
                        &its->phys_base, its_base_type_string[type],
                        its->device_ids, ids);
        }

        *order = new_order;

        return indirect;
}

static void its_free_tables(struct its_node *its)
{
        int i;

        for (i = 0; i < GITS_BASER_NR_REGS; i++) {
                if (its->tables[i].base) {
                        free_pages((unsigned long)its->tables[i].base,
                                   its->tables[i].order);
                        its->tables[i].base = NULL;
                }
        }
}

static int its_alloc_tables(struct its_node *its)
{
        u64 shr = GITS_BASER_InnerShareable;
        u64 cache = GITS_BASER_RaWaWb;
        u32 psz = SZ_64K;
        int err, i;

        if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_22375)
                /* erratum 24313: ignore memory access type */
                cache = GITS_BASER_nCnB;

        for (i = 0; i < GITS_BASER_NR_REGS; i++) {
                struct its_baser *baser = its->tables + i;
                u64 val = its_read_baser(its, baser);
                u64 type = GITS_BASER_TYPE(val);
                u32 order = get_order(psz);
                bool indirect = false;

                switch (type) {
                case GITS_BASER_TYPE_NONE:
                        continue;

                case GITS_BASER_TYPE_DEVICE:
                        indirect = its_parse_indirect_baser(its, baser,
                                                            psz, &order,
                                                            its->device_ids);
                        break;

                case GITS_BASER_TYPE_VCPU:
                        indirect = its_parse_indirect_baser(its, baser,
                                                            psz, &order,
                                                            ITS_MAX_VPEID_BITS);
                        break;
                }

                err = its_setup_baser(its, baser, cache, shr, psz, order, indirect);
                if (err < 0) {
                        its_free_tables(its);
                        return err;
                }

                /* Update settings which will be used for next BASERn */
                psz = baser->psz;
                cache = baser->val & GITS_BASER_CACHEABILITY_MASK;
                shr = baser->val & GITS_BASER_SHAREABILITY_MASK;
        }

        return 0;
}

static int its_alloc_collections(struct its_node *its)
{
        int i;

        its->collections = kcalloc(nr_cpu_ids, sizeof(*its->collections),
                                   GFP_KERNEL);
        if (!its->collections)
                return -ENOMEM;

        for (i = 0; i < nr_cpu_ids; i++)
                its->collections[i].target_address = ~0ULL;

        return 0;
}

static struct page *its_allocate_pending_table(gfp_t gfp_flags)
{
        struct page *pend_page;

        pend_page = alloc_pages(gfp_flags | __GFP_ZERO,
                                get_order(LPI_PENDBASE_SZ));
        if (!pend_page)
                return NULL;

        /* Make sure the GIC will observe the zero-ed page */
        gic_flush_dcache_to_poc(page_address(pend_page), LPI_PENDBASE_SZ);

        return pend_page;
}

static void its_free_pending_table(struct page *pt)
{
        free_pages((unsigned long)page_address(pt), get_order(LPI_PENDBASE_SZ));
}

/*
 * Booting with kdump and LPIs enabled is generally fine. Any other
 * case is wrong in the absence of firmware/EFI support.
 */
static bool enabled_lpis_allowed(void)
{
        phys_addr_t addr;
        u64 val;

        /* Check whether the property table is in a reserved region */
        val = gicr_read_propbaser(gic_data_rdist_rd_base() + GICR_PROPBASER);
        addr = val & GENMASK_ULL(51, 12);

        return gic_check_reserved_range(addr, LPI_PROPBASE_SZ);
}

static int __init allocate_lpi_tables(void)
{
        u64 val;
        int err, cpu;

        /*
         * If LPIs are enabled while we run this from the boot CPU,
         * flag the RD tables as pre-allocated if the stars do align.
         */
        val = readl_relaxed(gic_data_rdist_rd_base() + GICR_CTLR);
        if ((val & GICR_CTLR_ENABLE_LPIS) && enabled_lpis_allowed()) {
                gic_rdists->flags |= (RDIST_FLAGS_RD_TABLES_PREALLOCATED |
                                      RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING);
                pr_info("GICv3: Using preallocated redistributor tables\n");
        }

        err = its_setup_lpi_prop_table();
        if (err)
                return err;

        /*
         * We allocate all the pending tables anyway, as we may have a
         * mix of RDs that have had LPIs enabled, and some that
         * don't. We'll free the unused ones as each CPU comes online.
         */
        for_each_possible_cpu(cpu) {
                struct page *pend_page;

                pend_page = its_allocate_pending_table(GFP_NOWAIT);
                if (!pend_page) {
                        pr_err("Failed to allocate PENDBASE for CPU%d\n", cpu);
                        return -ENOMEM;
                }

                gic_data_rdist_cpu(cpu)->pend_page = pend_page;
        }

        return 0;
}

static u64 its_clear_vpend_valid(void __iomem *vlpi_base)
{
        u32 count = 1000000;    /* 1s! */
        bool clean;
        u64 val;

        val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER);
        val &= ~GICR_VPENDBASER_Valid;
        gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER);

        do {
                val = gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER);
                clean = !(val & GICR_VPENDBASER_Dirty);
                if (!clean) {
                        count--;
                        cpu_relax();
                        udelay(1);
                }
        } while (!clean && count);

        return val;
}

static void its_cpu_init_lpis(void)
{
        void __iomem *rbase = gic_data_rdist_rd_base();
        struct page *pend_page;
        phys_addr_t paddr;
        u64 val, tmp;

        if (gic_data_rdist()->lpi_enabled)
                return;

        val = readl_relaxed(rbase + GICR_CTLR);
        if ((gic_rdists->flags & RDIST_FLAGS_RD_TABLES_PREALLOCATED) &&
            (val & GICR_CTLR_ENABLE_LPIS)) {
                /*
                 * Check that we get the same property table on all
                 * RDs. If we don't, this is hopeless.
                 */
                paddr = gicr_read_propbaser(rbase + GICR_PROPBASER);
                paddr &= GENMASK_ULL(51, 12);
                if (WARN_ON(gic_rdists->prop_table_pa != paddr))
                        add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);

                paddr = gicr_read_pendbaser(rbase + GICR_PENDBASER);
                paddr &= GENMASK_ULL(51, 16);

                WARN_ON(!gic_check_reserved_range(paddr, LPI_PENDBASE_SZ));
                its_free_pending_table(gic_data_rdist()->pend_page);
                gic_data_rdist()->pend_page = NULL;

                goto out;
        }

        pend_page = gic_data_rdist()->pend_page;
        paddr = page_to_phys(pend_page);
        WARN_ON(gic_reserve_range(paddr, LPI_PENDBASE_SZ));

        /* set PROPBASE */
        val = (gic_rdists->prop_table_pa |
               GICR_PROPBASER_InnerShareable |
               GICR_PROPBASER_RaWaWb |
               ((LPI_NRBITS - 1) & GICR_PROPBASER_IDBITS_MASK));

        gicr_write_propbaser(val, rbase + GICR_PROPBASER);
        tmp = gicr_read_propbaser(rbase + GICR_PROPBASER);

        if ((tmp ^ val) & GICR_PROPBASER_SHAREABILITY_MASK) {
                if (!(tmp & GICR_PROPBASER_SHAREABILITY_MASK)) {
                        /*
                         * The HW reports non-shareable, we must
                         * remove the cacheability attributes as
                         * well.
                         */
                        val &= ~(GICR_PROPBASER_SHAREABILITY_MASK |
                                 GICR_PROPBASER_CACHEABILITY_MASK);
                        val |= GICR_PROPBASER_nC;
                        gicr_write_propbaser(val, rbase + GICR_PROPBASER);
                }
                pr_info_once("GIC: using cache flushing for LPI property table\n");
                gic_rdists->flags |= RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING;
        }

        /* set PENDBASE */
        val = (page_to_phys(pend_page) |
               GICR_PENDBASER_InnerShareable |
               GICR_PENDBASER_RaWaWb);

        gicr_write_pendbaser(val, rbase + GICR_PENDBASER);
        tmp = gicr_read_pendbaser(rbase + GICR_PENDBASER);

        if (!(tmp & GICR_PENDBASER_SHAREABILITY_MASK)) {
                /*
                 * The HW reports non-shareable, we must remove the
                 * cacheability attributes as well.
                 */
                val &= ~(GICR_PENDBASER_SHAREABILITY_MASK |
                         GICR_PENDBASER_CACHEABILITY_MASK);
                val |= GICR_PENDBASER_nC;
                gicr_write_pendbaser(val, rbase + GICR_PENDBASER);
        }

        /* Enable LPIs */
        val = readl_relaxed(rbase + GICR_CTLR);
        val |= GICR_CTLR_ENABLE_LPIS;
        writel_relaxed(val, rbase + GICR_CTLR);

        if (gic_rdists->has_vlpis) {
                void __iomem *vlpi_base = gic_data_rdist_vlpi_base();

                /*
                 * It's possible for CPU to receive VLPIs before it is
                 * sheduled as a vPE, especially for the first CPU, and the
                 * VLPI with INTID larger than 2^(IDbits+1) will be considered
                 * as out of range and dropped by GIC.
                 * So we initialize IDbits to known value to avoid VLPI drop.
                 */
                val = (LPI_NRBITS - 1) & GICR_VPROPBASER_IDBITS_MASK;
                pr_debug("GICv4: CPU%d: Init IDbits to 0x%llx for GICR_VPROPBASER\n",
                        smp_processor_id(), val);
                gits_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER);

                /*
                 * Also clear Valid bit of GICR_VPENDBASER, in case some
                 * ancient programming gets left in and has possibility of
                 * corrupting memory.
                 */
                val = its_clear_vpend_valid(vlpi_base);
                WARN_ON(val & GICR_VPENDBASER_Dirty);
        }

        /* Make sure the GIC has seen the above */
        dsb(sy);
out:
        gic_data_rdist()->lpi_enabled = true;
        pr_info("GICv3: CPU%d: using %s LPI pending table @%pa\n",
                smp_processor_id(),
                gic_data_rdist()->pend_page ? "allocated" : "reserved",
                &paddr);
}

static void its_cpu_init_collection(struct its_node *its)
{
        int cpu = smp_processor_id();
        u64 target;

        /* avoid cross node collections and its mapping */
        if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144) {
                struct device_node *cpu_node;

                cpu_node = of_get_cpu_node(cpu, NULL);
                if (its->numa_node != NUMA_NO_NODE &&
                        its->numa_node != of_node_to_nid(cpu_node))
                        return;
        }

        /*
         * We now have to bind each collection to its target
         * redistributor.
         */
        if (gic_read_typer(its->base + GITS_TYPER) & GITS_TYPER_PTA) {
                /*
                 * This ITS wants the physical address of the
                 * redistributor.
                 */
                target = gic_data_rdist()->phys_base;
        } else {
                /* This ITS wants a linear CPU number. */
                target = gic_read_typer(gic_data_rdist_rd_base() + GICR_TYPER);
                target = GICR_TYPER_CPU_NUMBER(target) << 16;
        }

        /* Perform collection mapping */
        its->collections[cpu].target_address = target;
        its->collections[cpu].col_id = cpu;

        its_send_mapc(its, &its->collections[cpu], 1);
        its_send_invall(its, &its->collections[cpu]);
}

static void its_cpu_init_collections(void)
{
        struct its_node *its;

        raw_spin_lock(&its_lock);

        list_for_each_entry(its, &its_nodes, entry)
                its_cpu_init_collection(its);

        raw_spin_unlock(&its_lock);
}

static struct its_device *its_find_device(struct its_node *its, u32 dev_id)
{
        struct its_device *its_dev = NULL, *tmp;
        unsigned long flags;

        raw_spin_lock_irqsave(&its->lock, flags);

        list_for_each_entry(tmp, &its->its_device_list, entry) {
                if (tmp->device_id == dev_id) {
                        its_dev = tmp;
                        break;
                }
        }

        raw_spin_unlock_irqrestore(&its->lock, flags);

        return its_dev;
}

static struct its_baser *its_get_baser(struct its_node *its, u32 type)
{
        int i;

        for (i = 0; i < GITS_BASER_NR_REGS; i++) {
                if (GITS_BASER_TYPE(its->tables[i].val) == type)
                        return &its->tables[i];
        }

        return NULL;
}

static bool its_alloc_table_entry(struct its_node *its,
                                  struct its_baser *baser, u32 id)
{
        struct page *page;
        u32 esz, idx;
        __le64 *table;

        /* Don't allow device id that exceeds single, flat table limit */
        esz = GITS_BASER_ENTRY_SIZE(baser->val);
        if (!(baser->val & GITS_BASER_INDIRECT))
                return (id < (PAGE_ORDER_TO_SIZE(baser->order) / esz));

        /* Compute 1st level table index & check if that exceeds table limit */
        idx = id >> ilog2(baser->psz / esz);
        if (idx >= (PAGE_ORDER_TO_SIZE(baser->order) / GITS_LVL1_ENTRY_SIZE))
                return false;

        table = baser->base;

        /* Allocate memory for 2nd level table */
        if (!table[idx]) {
                page = alloc_pages_node(its->numa_node, GFP_KERNEL | __GFP_ZERO,
                                        get_order(baser->psz));
                if (!page)
                        return false;

                /* Flush Lvl2 table to PoC if hw doesn't support coherency */
                if (!(baser->val & GITS_BASER_SHAREABILITY_MASK))
                        gic_flush_dcache_to_poc(page_address(page), baser->psz);

                table[idx] = cpu_to_le64(page_to_phys(page) | GITS_BASER_VALID);

                /* Flush Lvl1 entry to PoC if hw doesn't support coherency */
                if (!(baser->val & GITS_BASER_SHAREABILITY_MASK))
                        gic_flush_dcache_to_poc(table + idx, GITS_LVL1_ENTRY_SIZE);

                /* Ensure updated table contents are visible to ITS hardware */
                dsb(sy);
        }

        return true;
}

static bool its_alloc_device_table(struct its_node *its, u32 dev_id)
{
        struct its_baser *baser;

        baser = its_get_baser(its, GITS_BASER_TYPE_DEVICE);

        /* Don't allow device id that exceeds ITS hardware limit */
        if (!baser)
                return (ilog2(dev_id) < its->device_ids);

        return its_alloc_table_entry(its, baser, dev_id);
}

static bool its_alloc_vpe_table(u32 vpe_id)
{
        struct its_node *its;

        /*
         * Make sure the L2 tables are allocated on *all* v4 ITSs. We
         * could try and only do it on ITSs corresponding to devices
         * that have interrupts targeted at this VPE, but the
         * complexity becomes crazy (and you have tons of memory
         * anyway, right?).
         */
        list_for_each_entry(its, &its_nodes, entry) {
                struct its_baser *baser;

                if (!its->is_v4)
                        continue;

                baser = its_get_baser(its, GITS_BASER_TYPE_VCPU);
                if (!baser)
                        return false;

                if (!its_alloc_table_entry(its, baser, vpe_id))
                        return false;
        }

        return true;
}

static struct its_device *its_create_device(struct its_node *its, u32 dev_id,
                                            int nvecs, bool alloc_lpis)
{
        struct its_device *dev;
        unsigned long *lpi_map = NULL;
        unsigned long flags;
        u16 *col_map = NULL;
        void *itt;
        int lpi_base;
        int nr_lpis;
        int nr_ites;
        int sz;

        if (!its_alloc_device_table(its, dev_id))
                return NULL;

        if (WARN_ON(!is_power_of_2(nvecs)))
                nvecs = roundup_pow_of_two(nvecs);

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        /*
         * Even if the device wants a single LPI, the ITT must be
         * sized as a power of two (and you need at least one bit...).
         */
        nr_ites = max(2, nvecs);
        sz = nr_ites * its->ite_size;
        sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
        itt = kzalloc_node(sz, GFP_KERNEL, its->numa_node);
        if (alloc_lpis) {
                lpi_map = its_lpi_alloc(nvecs, &lpi_base, &nr_lpis);
                if (lpi_map)
                        col_map = kcalloc(nr_lpis, sizeof(*col_map),
                                          GFP_KERNEL);
        } else {
                col_map = kcalloc(nr_ites, sizeof(*col_map), GFP_KERNEL);
                nr_lpis = 0;
                lpi_base = 0;
        }

        if (!dev || !itt ||  !col_map || (!lpi_map && alloc_lpis)) {
                kfree(dev);
                kfree(itt);
                kfree(lpi_map);
                kfree(col_map);
                return NULL;
        }

        gic_flush_dcache_to_poc(itt, sz);

        dev->its = its;
        dev->itt = itt;
        dev->nr_ites = nr_ites;
        dev->event_map.lpi_map = lpi_map;
        dev->event_map.col_map = col_map;
        dev->event_map.lpi_base = lpi_base;
        dev->event_map.nr_lpis = nr_lpis;
        mutex_init(&dev->event_map.vlpi_lock);
        dev->device_id = dev_id;
        INIT_LIST_HEAD(&dev->entry);

        raw_spin_lock_irqsave(&its->lock, flags);
        list_add(&dev->entry, &its->its_device_list);
        raw_spin_unlock_irqrestore(&its->lock, flags);

        /* Map device to its ITT */
        its_send_mapd(dev, 1);

        return dev;
}

static void its_free_device(struct its_device *its_dev)
{
        unsigned long flags;

        raw_spin_lock_irqsave(&its_dev->its->lock, flags);
        list_del(&its_dev->entry);
        raw_spin_unlock_irqrestore(&its_dev->its->lock, flags);
        kfree(its_dev->itt);
        kfree(its_dev);
}

static int its_alloc_device_irq(struct its_device *dev, int nvecs, irq_hw_number_t *hwirq)
{
        int idx;

        idx = bitmap_find_free_region(dev->event_map.lpi_map,
                                      dev->event_map.nr_lpis,
                                      get_count_order(nvecs));
        if (idx < 0)
                return -ENOSPC;

        *hwirq = dev->event_map.lpi_base + idx;
        set_bit(idx, dev->event_map.lpi_map);

        return 0;
}

static int its_msi_prepare(struct irq_domain *domain, struct device *dev,
                           int nvec, msi_alloc_info_t *info)
{
        struct its_node *its;
        struct its_device *its_dev;
        struct msi_domain_info *msi_info;
        u32 dev_id;
        int err = 0;

        /*
         * We ignore "dev" entirely, and rely on the dev_id that has
         * been passed via the scratchpad. This limits this domain's
         * usefulness to upper layers that definitely know that they
         * are built on top of the ITS.
         */
        dev_id = info->scratchpad[0].ul;

        msi_info = msi_get_domain_info(domain);
        its = msi_info->data;

        if (!gic_rdists->has_direct_lpi &&
            vpe_proxy.dev &&
            vpe_proxy.dev->its == its &&
            dev_id == vpe_proxy.dev->device_id) {
                /* Bad luck. Get yourself a better implementation */
                WARN_ONCE(1, "DevId %x clashes with GICv4 VPE proxy device\n",
                          dev_id);
                return -EINVAL;
        }

        mutex_lock(&its->dev_alloc_lock);
        its_dev = its_find_device(its, dev_id);
        if (its_dev) {
                /*
                 * We already have seen this ID, probably through
                 * another alias (PCI bridge of some sort). No need to
                 * create the device.
                 */
                its_dev->shared = true;
                pr_debug("Reusing ITT for devID %x\n", dev_id);
                goto out;
        }

        its_dev = its_create_device(its, dev_id, nvec, true);
        if (!its_dev) {
                err = -ENOMEM;
                goto out;
        }

        pr_debug("ITT %d entries, %d bits\n", nvec, ilog2(nvec));
out:
        mutex_unlock(&its->dev_alloc_lock);
        info->scratchpad[0].ptr = its_dev;
        return err;
}

static struct msi_domain_ops its_msi_domain_ops = {
        .msi_prepare    = its_msi_prepare,
};

static int its_irq_gic_domain_alloc(struct irq_domain *domain,
                                    unsigned int virq,
                                    irq_hw_number_t hwirq)
{
        struct irq_fwspec fwspec;

        if (irq_domain_get_of_node(domain->parent)) {
                fwspec.fwnode = domain->parent->fwnode;
                fwspec.param_count = 3;
                fwspec.param[0] = GIC_IRQ_TYPE_LPI;
                fwspec.param[1] = hwirq;
                fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
        } else if (is_fwnode_irqchip(domain->parent->fwnode)) {
                fwspec.fwnode = domain->parent->fwnode;
                fwspec.param_count = 2;
                fwspec.param[0] = hwirq;
                fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
        } else {
                return -EINVAL;
        }

        return irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
}

static int its_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
                                unsigned int nr_irqs, void *args)
{
        msi_alloc_info_t *info = args;
        struct its_device *its_dev = info->scratchpad[0].ptr;
        struct its_node *its = its_dev->its;
        irq_hw_number_t hwirq;
        int err;
        int i;

        err = its_alloc_device_irq(its_dev, nr_irqs, &hwirq);
        if (err)
                return err;

        err = iommu_dma_prepare_msi(info->desc, its->get_msi_base(its_dev));
        if (err)
                return err;

        for (i = 0; i < nr_irqs; i++) {
                err = its_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
                if (err)
                        return err;

                irq_domain_set_hwirq_and_chip(domain, virq + i,
                                              hwirq + i, &its_irq_chip, its_dev);
                irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq + i)));
                pr_debug("ID:%d pID:%d vID:%d\n",
                         (int)(hwirq + i - its_dev->event_map.lpi_base),
                         (int)(hwirq + i), virq + i);
        }

        return 0;
}

static int its_irq_domain_activate(struct irq_domain *domain,
                                   struct irq_data *d, bool reserve)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);
        const struct cpumask *cpu_mask = cpu_online_mask;
        int cpu;

        /* get the cpu_mask of local node */
        if (its_dev->its->numa_node >= 0)
                cpu_mask = cpumask_of_node(its_dev->its->numa_node);

        /* Bind the LPI to the first possible CPU */
        cpu = cpumask_first_and(cpu_mask, cpu_online_mask);
        if (cpu >= nr_cpu_ids) {
                if (its_dev->its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_23144)
                        return -EINVAL;

                cpu = cpumask_first(cpu_online_mask);
        }

        its_dev->event_map.col_map[event] = cpu;
        irq_data_update_effective_affinity(d, cpumask_of(cpu));

        /* Map the GIC IRQ and event to the device */
        its_send_mapti(its_dev, d->hwirq, event);
        return 0;
}

static void its_irq_domain_deactivate(struct irq_domain *domain,
                                      struct irq_data *d)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        u32 event = its_get_event_id(d);

        /* Stop the delivery of interrupts */
        its_send_discard(its_dev, event);
}

static void its_irq_domain_free(struct irq_domain *domain, unsigned int virq,
                                unsigned int nr_irqs)
{
        struct irq_data *d = irq_domain_get_irq_data(domain, virq);
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        struct its_node *its = its_dev->its;
        int i;

        for (i = 0; i < nr_irqs; i++) {
                struct irq_data *data = irq_domain_get_irq_data(domain,
                                                                virq + i);
                u32 event = its_get_event_id(data);

                /* Mark interrupt index as unused */
                clear_bit(event, its_dev->event_map.lpi_map);

                /* Nuke the entry in the domain */
                irq_domain_reset_irq_data(data);
        }

        mutex_lock(&its->dev_alloc_lock);

        /*
         * If all interrupts have been freed, start mopping the
         * floor. This is conditionned on the device not being shared.
         */
        if (!its_dev->shared &&
            bitmap_empty(its_dev->event_map.lpi_map,
                         its_dev->event_map.nr_lpis)) {
                its_lpi_free(its_dev->event_map.lpi_map,
                             its_dev->event_map.lpi_base,
                             its_dev->event_map.nr_lpis);
                kfree(its_dev->event_map.col_map);

                /* Unmap device/itt */
                its_send_mapd(its_dev, 0);
                its_free_device(its_dev);
        }

        mutex_unlock(&its->dev_alloc_lock);

        irq_domain_free_irqs_parent(domain, virq, nr_irqs);
}

static const struct irq_domain_ops its_domain_ops = {
        .alloc                  = its_irq_domain_alloc,
        .free                   = its_irq_domain_free,
        .activate               = its_irq_domain_activate,
        .deactivate             = its_irq_domain_deactivate,
};

/*
 * This is insane.
 *
 * If a GICv4 doesn't implement Direct LPIs (which is extremely
 * likely), the only way to perform an invalidate is to use a fake
 * device to issue an INV command, implying that the LPI has first
 * been mapped to some event on that device. Since this is not exactly
 * cheap, we try to keep that mapping around as long as possible, and
 * only issue an UNMAP if we're short on available slots.
 *
 * Broken by design(tm).
 */
static void its_vpe_db_proxy_unmap_locked(struct its_vpe *vpe)
{
        /* Already unmapped? */
        if (vpe->vpe_proxy_event == -1)
                return;

        its_send_discard(vpe_proxy.dev, vpe->vpe_proxy_event);
        vpe_proxy.vpes[vpe->vpe_proxy_event] = NULL;

        /*
         * We don't track empty slots at all, so let's move the
         * next_victim pointer if we can quickly reuse that slot
         * instead of nuking an existing entry. Not clear that this is
         * always a win though, and this might just generate a ripple
         * effect... Let's just hope VPEs don't migrate too often.
         */
        if (vpe_proxy.vpes[vpe_proxy.next_victim])
                vpe_proxy.next_victim = vpe->vpe_proxy_event;

        vpe->vpe_proxy_event = -1;
}

static void its_vpe_db_proxy_unmap(struct its_vpe *vpe)
{
        if (!gic_rdists->has_direct_lpi) {
                unsigned long flags;

                raw_spin_lock_irqsave(&vpe_proxy.lock, flags);
                its_vpe_db_proxy_unmap_locked(vpe);
                raw_spin_unlock_irqrestore(&vpe_proxy.lock, flags);
        }
}

static void its_vpe_db_proxy_map_locked(struct its_vpe *vpe)
{
        /* Already mapped? */
        if (vpe->vpe_proxy_event != -1)
                return;

        /* This slot was already allocated. Kick the other VPE out. */
        if (vpe_proxy.vpes[vpe_proxy.next_victim])
                its_vpe_db_proxy_unmap_locked(vpe_proxy.vpes[vpe_proxy.next_victim]);

        /* Map the new VPE instead */
        vpe_proxy.vpes[vpe_proxy.next_victim] = vpe;
        vpe->vpe_proxy_event = vpe_proxy.next_victim;
        vpe_proxy.next_victim = (vpe_proxy.next_victim + 1) % vpe_proxy.dev->nr_ites;

        vpe_proxy.dev->event_map.col_map[vpe->vpe_proxy_event] = vpe->col_idx;
        its_send_mapti(vpe_proxy.dev, vpe->vpe_db_lpi, vpe->vpe_proxy_event);
}

static void its_vpe_db_proxy_move(struct its_vpe *vpe, int from, int to)
{
        unsigned long flags;
        struct its_collection *target_col;

        if (gic_rdists->has_direct_lpi) {
                void __iomem *rdbase;

                rdbase = per_cpu_ptr(gic_rdists->rdist, from)->rd_base;
                gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_CLRLPIR);
                while (gic_read_lpir(rdbase + GICR_SYNCR) & 1)
                        cpu_relax();

                return;
        }

        raw_spin_lock_irqsave(&vpe_proxy.lock, flags);

        its_vpe_db_proxy_map_locked(vpe);

        target_col = &vpe_proxy.dev->its->collections[to];
        its_send_movi(vpe_proxy.dev, target_col, vpe->vpe_proxy_event);
        vpe_proxy.dev->event_map.col_map[vpe->vpe_proxy_event] = to;

        raw_spin_unlock_irqrestore(&vpe_proxy.lock, flags);
}

static int its_vpe_set_affinity(struct irq_data *d,
                                const struct cpumask *mask_val,
                                bool force)
{
        struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
        int cpu = cpumask_first(mask_val);

        /*
         * Changing affinity is mega expensive, so let's be as lazy as
         * we can and only do it if we really have to. Also, if mapped
         * into the proxy device, we need to move the doorbell
         * interrupt to its new location.
         */
        if (vpe->col_idx != cpu) {
                int from = vpe->col_idx;

                vpe->col_idx = cpu;
                its_send_vmovp(vpe);
                its_vpe_db_proxy_move(vpe, from, cpu);
        }

        irq_data_update_effective_affinity(d, cpumask_of(cpu));

        return IRQ_SET_MASK_OK_DONE;
}

static void its_vpe_schedule(struct its_vpe *vpe)
{
        void __iomem *vlpi_base = gic_data_rdist_vlpi_base();
        u64 val;

        /* Schedule the VPE */
        val  = virt_to_phys(page_address(vpe->its_vm->vprop_page)) &
                GENMASK_ULL(51, 12);
        val |= (LPI_NRBITS - 1) & GICR_VPROPBASER_IDBITS_MASK;
        val |= GICR_VPROPBASER_RaWb;
        val |= GICR_VPROPBASER_InnerShareable;
        gits_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER);

        val  = virt_to_phys(page_address(vpe->vpt_page)) &
                GENMASK_ULL(51, 16);
        val |= GICR_VPENDBASER_RaWaWb;
        val |= GICR_VPENDBASER_NonShareable;
        /*
         * There is no good way of finding out if the pending table is
         * empty as we can race against the doorbell interrupt very
         * easily. So in the end, vpe->pending_last is only an
         * indication that the vcpu has something pending, not one
         * that the pending table is empty. A good implementation
         * would be able to read its coarse map pretty quickly anyway,
         * making this a tolerable issue.
         */
        val |= GICR_VPENDBASER_PendingLast;
        val |= vpe->idai ? GICR_VPENDBASER_IDAI : 0;
        val |= GICR_VPENDBASER_Valid;
        gits_write_vpendbaser(val, vlpi_base + GICR_VPENDBASER);
}

static void its_vpe_deschedule(struct its_vpe *vpe)
{
        void __iomem *vlpi_base = gic_data_rdist_vlpi_base();
        u64 val;

        val = its_clear_vpend_valid(vlpi_base);

        if (unlikely(val & GICR_VPENDBASER_Dirty)) {
                pr_err_ratelimited("ITS virtual pending table not cleaning\n");
                vpe->idai = false;
                vpe->pending_last = true;
        } else {
                vpe->idai = !!(val & GICR_VPENDBASER_IDAI);
                vpe->pending_last = !!(val & GICR_VPENDBASER_PendingLast);
        }
}

static void its_vpe_invall(struct its_vpe *vpe)
{
        struct its_node *its;

        list_for_each_entry(its, &its_nodes, entry) {
                if (!its->is_v4)
                        continue;

                if (its_list_map && !vpe->its_vm->vlpi_count[its->list_nr])
                        continue;

                /*
                 * Sending a VINVALL to a single ITS is enough, as all
                 * we need is to reach the redistributors.
                 */
                its_send_vinvall(its, vpe);
                return;
        }
}

static int its_vpe_set_vcpu_affinity(struct irq_data *d, void *vcpu_info)
{
        struct its_vpe *vpe = irq_data_get_irq_chip_data(d);
        struct its_cmd_info *info = vcpu_info;

        switch (info->cmd_type) {
        case SCHEDULE_VPE:
                its_vpe_schedule(vpe);
                return 0;

        case DESCHEDULE_VPE:
                its_vpe_deschedule(vpe);
                return 0;

        case INVALL_VPE:
                its_vpe_invall(vpe);
                return 0;

        default:
                return -EINVAL;
        }
}

static void its_vpe_send_cmd(struct its_vpe *vpe,
                             void (*cmd)(struct its_device *, u32))
{
        unsigned long flags;

        raw_spin_lock_irqsave(&vpe_proxy.lock, flags);

        its_vpe_db_proxy_map_locked(vpe);
        cmd(vpe_proxy.dev, vpe->vpe_proxy_event);

        raw_spin_unlock_irqrestore(&vpe_proxy.lock, flags);
}

static void its_vpe_send_inv(struct irq_data *d)
{
        struct its_vpe *vpe = irq_data_get_irq_chip_data(d);

        if (gic_rdists->has_direct_lpi) {
                void __iomem *rdbase;

                rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
                gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_INVLPIR);
                while (gic_read_lpir(rdbase + GICR_SYNCR) & 1)
                        cpu_relax();
        } else {
                its_vpe_send_cmd(vpe, its_send_inv);
        }
}

static void its_vpe_mask_irq(struct irq_data *d)
{
        /*
         * We need to unmask the LPI, which is described by the parent
         * irq_data. Instead of calling into the parent (which won't
         * exactly do the right thing, let's simply use the
         * parent_data pointer. Yes, I'm naughty.
         */
        lpi_write_config(d->parent_data, LPI_PROP_ENABLED, 0);
        its_vpe_send_inv(d);
}

static void its_vpe_unmask_irq(struct irq_data *d)
{
        /* Same hack as above... */
        lpi_write_config(d->parent_data, 0, LPI_PROP_ENABLED);
        its_vpe_send_inv(d);
}

static int its_vpe_set_irqchip_state(struct irq_data *d,
                                     enum irqchip_irq_state which,
                                     bool state)
{
        struct its_vpe *vpe = irq_data_get_irq_chip_data(d);

        if (which != IRQCHIP_STATE_PENDING)
                return -EINVAL;

        if (gic_rdists->has_direct_lpi) {
                void __iomem *rdbase;

                rdbase = per_cpu_ptr(gic_rdists->rdist, vpe->col_idx)->rd_base;
                if (state) {
                        gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_SETLPIR);
                } else {
                        gic_write_lpir(vpe->vpe_db_lpi, rdbase + GICR_CLRLPIR);
                        while (gic_read_lpir(rdbase + GICR_SYNCR) & 1)
                                cpu_relax();
                }
        } else {
                if (state)
                        its_vpe_send_cmd(vpe, its_send_int);
                else
                        its_vpe_send_cmd(vpe, its_send_clear);
        }

        return 0;
}

static struct irq_chip its_vpe_irq_chip = {
        .name                   = "GICv4-vpe",
        .irq_mask               = its_vpe_mask_irq,
        .irq_unmask             = its_vpe_unmask_irq,
        .irq_eoi                = irq_chip_eoi_parent,
        .irq_set_affinity       = its_vpe_set_affinity,
        .irq_set_irqchip_state  = its_vpe_set_irqchip_state,
        .irq_set_vcpu_affinity  = its_vpe_set_vcpu_affinity,
};

static int its_vpe_id_alloc(void)
{
        return ida_simple_get(&its_vpeid_ida, 0, ITS_MAX_VPEID, GFP_KERNEL);
}

static void its_vpe_id_free(u16 id)
{
        ida_simple_remove(&its_vpeid_ida, id);
}

static int its_vpe_init(struct its_vpe *vpe)
{
        struct page *vpt_page;
        int vpe_id;

        /* Allocate vpe_id */
        vpe_id = its_vpe_id_alloc();