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

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

#include <linux/amba/bus.h>

#include "arm-smmu-v3.h"
#include "../../iommu-sva-lib.h"

static bool disable_bypass = true;
module_param(disable_bypass, bool, 0444);
MODULE_PARM_DESC(disable_bypass,
        "Disable bypass streams such that incoming transactions from devices that are not attached to an iommu domain will report an abort back to the device and will not be allowed to pass through the SMMU.");

static bool disable_msipolling;
module_param(disable_msipolling, bool, 0444);
MODULE_PARM_DESC(disable_msipolling,
        "Disable MSI-based polling for CMD_SYNC completion.");

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

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

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

DEFINE_XARRAY_ALLOC1(arm_smmu_asid_xa);
DEFINE_MUTEX(arm_smmu_asid_lock);

/*
 * Special value used by SVA when a process dies, to quiesce a CD without
 * disabling it.
 */
struct arm_smmu_ctx_desc quiet_cd = { 0 };

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

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

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

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

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

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

        return space >= n;
}

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

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

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

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

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

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

        /*
         * We can't use the _relaxed() variant here, as we must prevent
         * speculative reads of the queue before we have determined that
         * prod has indeed moved.
         */
        prod = readl(q->prod_reg);

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

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

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

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

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

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

        return 0;
}

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

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

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

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

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

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

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

        switch (ent->opcode) {
        case CMDQ_OP_TLBI_EL2_ALL:
        case CMDQ_OP_TLBI_NSNH_ALL:
                break;
        case CMDQ_OP_PREFETCH_CFG:
                cmd[0] |= FIELD_PREP(CMDQ_PREFETCH_0_SID, ent->prefetch.sid);
                break;
        case CMDQ_OP_CFGI_CD:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SSID, ent->cfgi.ssid);
                fallthrough;
        case CMDQ_OP_CFGI_STE:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
                cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_LEAF, ent->cfgi.leaf);
                break;
        case CMDQ_OP_CFGI_CD_ALL:
                cmd[0] |= FIELD_PREP(CMDQ_CFGI_0_SID, ent->cfgi.sid);
                break;
        case CMDQ_OP_CFGI_ALL:
                /* Cover the entire SID range */
                cmd[1] |= FIELD_PREP(CMDQ_CFGI_1_RANGE, 31);
                break;
        case CMDQ_OP_TLBI_NH_VA:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                fallthrough;
        case CMDQ_OP_TLBI_EL2_VA:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_VA_MASK;
                break;
        case CMDQ_OP_TLBI_S2_IPA:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_NUM, ent->tlbi.num);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_SCALE, ent->tlbi.scale);
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_LEAF, ent->tlbi.leaf);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TTL, ent->tlbi.ttl);
                cmd[1] |= FIELD_PREP(CMDQ_TLBI_1_TG, ent->tlbi.tg);
                cmd[1] |= ent->tlbi.addr & CMDQ_TLBI_1_IPA_MASK;
                break;
        case CMDQ_OP_TLBI_NH_ASID:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
                fallthrough;
        case CMDQ_OP_TLBI_S12_VMALL:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_VMID, ent->tlbi.vmid);
                break;
        case CMDQ_OP_TLBI_EL2_ASID:
                cmd[0] |= FIELD_PREP(CMDQ_TLBI_0_ASID, ent->tlbi.asid);
                break;
        case CMDQ_OP_ATC_INV:
                cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_GLOBAL, ent->atc.global);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SSID, ent->atc.ssid);
                cmd[0] |= FIELD_PREP(CMDQ_ATC_0_SID, ent->atc.sid);
                cmd[1] |= FIELD_PREP(CMDQ_ATC_1_SIZE, ent->atc.size);
                cmd[1] |= ent->atc.addr & CMDQ_ATC_1_ADDR_MASK;
                break;
        case CMDQ_OP_PRI_RESP:
                cmd[0] |= FIELD_PREP(CMDQ_0_SSV, ent->substream_valid);
                cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SSID, ent->pri.ssid);
                cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SID, ent->pri.sid);
                cmd[1] |= FIELD_PREP(CMDQ_PRI_1_GRPID, ent->pri.grpid);
                switch (ent->pri.resp) {
                case PRI_RESP_DENY:
                case PRI_RESP_FAIL:
                case PRI_RESP_SUCC:
                        break;
                default:
                        return -EINVAL;
                }
                cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
                break;
        case CMDQ_OP_RESUME:
                cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_SID, ent->resume.sid);
                cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_RESP, ent->resume.resp);
                cmd[1] |= FIELD_PREP(CMDQ_RESUME_1_STAG, ent->resume.stag);
                break;
        case CMDQ_OP_CMD_SYNC:
                if (ent->sync.msiaddr) {
                        cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_IRQ);
                        cmd[1] |= ent->sync.msiaddr & CMDQ_SYNC_1_MSIADDR_MASK;
                } else {
                        cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
                }
                cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSH, ARM_SMMU_SH_ISH);
                cmd[0] |= FIELD_PREP(CMDQ_SYNC_0_MSIATTR, ARM_SMMU_MEMATTR_OIWB);
                break;
        default:
                return -ENOENT;
        }

        return 0;
}

static struct arm_smmu_cmdq *arm_smmu_get_cmdq(struct arm_smmu_device *smmu)
{
        return &smmu->cmdq;
}

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

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

        arm_smmu_cmdq_build_cmd(cmd, &ent);
}

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

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

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

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

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

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

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

static void arm_smmu_cmdq_skip_err(struct arm_smmu_device *smmu)
{
        __arm_smmu_cmdq_skip_err(smmu, &smmu->cmdq.q);
}

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

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

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

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

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

        arm_smmu_cmdq_shared_unlock(cmdq);
        return true;
}

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

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


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

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

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

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

                ptr = &cmdq->valid_map[swidx];

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

                mask = GENMASK(limit - 1, sbidx);

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

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

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

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

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

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

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

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

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

        return ret;
}

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

        queue_poll_init(smmu, &qp);

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

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

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

                ret = queue_poll(&qp);

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

        return ret;
}

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

        return __arm_smmu_cmdq_poll_until_consumed(smmu, llq);
}

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

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

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

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

        llq.max_n_shift = cmdq->q.llq.max_n_shift;

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

        local_irq_restore(flags);
        return ret;
}

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

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

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

static int arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
                                   struct arm_smmu_cmdq_ent *ent)
{
        return __arm_smmu_cmdq_issue_cmd(smmu, ent, false);
}

static int arm_smmu_cmdq_issue_cmd_with_sync(struct arm_smmu_device *smmu,
                                             struct arm_smmu_cmdq_ent *ent)
{
        return __arm_smmu_cmdq_issue_cmd(smmu, ent, true);
}

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

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

static int arm_smmu_page_response(struct device *dev,
                                  struct iommu_fault_event *unused,
                                  struct iommu_page_response *resp)
{
        struct arm_smmu_cmdq_ent cmd = {0};
        struct arm_smmu_master *master = dev_iommu_priv_get(dev);
        int sid = master->streams[0].id;

        if (master->stall_enabled) {
                cmd.opcode              = CMDQ_OP_RESUME;
                cmd.resume.sid          = sid;
                cmd.resume.stag         = resp->grpid;
                switch (resp->code) {
                case IOMMU_PAGE_RESP_INVALID:
                case IOMMU_PAGE_RESP_FAILURE:
                        cmd.resume.resp = CMDQ_RESUME_0_RESP_ABORT;
                        break;
                case IOMMU_PAGE_RESP_SUCCESS:
                        cmd.resume.resp = CMDQ_RESUME_0_RESP_RETRY;
                        break;
                default:
                        return -EINVAL;
                }
        } else {
                return -ENODEV;
        }

        arm_smmu_cmdq_issue_cmd(master->smmu, &cmd);
        /*
         * Don't send a SYNC, it doesn't do anything for RESUME or PRI_RESP.
         * RESUME consumption guarantees that the stalled transaction will be
         * terminated... at some point in the future. PRI_RESP is fire and
         * forget.
         */

        return 0;
}

/* Context descriptor manipulation functions */
void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid)
{
        struct arm_smmu_cmdq_ent cmd = {
                .opcode = smmu->features & ARM_SMMU_FEAT_E2H ?
                        CMDQ_OP_TLBI_EL2_ASID : CMDQ_OP_TLBI_NH_ASID,
                .tlbi.asid = asid,
        };

        arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
}

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

        cmds.num = 0;

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

        arm_smmu_cmdq_batch_submit(smmu, &cmds);
}

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

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

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

                  CTXDESC_L1_DESC_V;

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

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

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

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

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

int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
                            struct arm_smmu_ctx_desc *cd)
{
        /*
         * This function handles the following cases:
         *
         * (1) Install primary CD, for normal DMA traffic (SSID = 0).
         * (2) Install a secondary CD, for SID+SSID traffic.
         * (3) Update ASID of a CD. Atomically write the first 64 bits of the
         *     CD, then invalidate the old entry and mappings.
         * (4) Quiesce the context without clearing the valid bit. Disable
         *     translation, and ignore any translation fault.
         * (5) Remove a secondary CD.
         */
        u64 val;
        bool cd_live;
        __le64 *cdptr;

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

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

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

        if (!cd) { /* (5) */
                val = 0;
        } else if (cd == &quiet_cd) { /* (4) */
                val |= CTXDESC_CD_0_TCR_EPD0;
        } else if (cd_live) { /* (3) */
                val &= ~CTXDESC_CD_0_ASID;
                val |= FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid);
                /*
                 * Until CD+TLB invalidation, both ASIDs may be used for tagging
                 * this substream's traffic
                 */
        } else { /* (1) and (2) */
                cdptr[1] = cpu_to_le64(cd->ttbr & CTXDESC_CD_1_TTB0_MASK);
                cdptr[2] = 0;
                cdptr[3] = cpu_to_le64(cd->mair);

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

                val = cd->tcr |
#ifdef __BIG_ENDIAN
                        CTXDESC_CD_0_ENDI |
#endif
                        CTXDESC_CD_0_R | CTXDESC_CD_0_A |
                        (cd->mm ? 0 : CTXDESC_CD_0_ASET) |
                        CTXDESC_CD_0_AA64 |
                        FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
                        CTXDESC_CD_0_V;

                if (smmu_domain->stall_enabled)
                        val |= CTXDESC_CD_0_S;
        }

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

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

        max_contexts = 1 << cfg->s1cdmax;

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

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

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

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

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

        return 0;

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

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

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

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

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

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

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

bool arm_smmu_free_asid(struct arm_smmu_ctx_desc *cd)
{
        bool free;
        struct arm_smmu_ctx_desc *old_cd;

        if (!cd->asid)
                return false;

        free = refcount_dec_and_test(&cd->refs);
        if (free) {
                old_cd = xa_erase(&arm_smmu_asid_xa, cd->asid);
                WARN_ON(old_cd != cd);
        }
        return free;
}

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

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

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

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

        arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
}

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

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

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

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

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

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

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

        if (s1_cfg) {
                u64 strw = smmu->features & ARM_SMMU_FEAT_E2H ?
                        STRTAB_STE_1_STRW_EL2 : STRTAB_STE_1_STRW_NSEL1;

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

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

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

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

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

                val |= FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S2_TRANS);
        }

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

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

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

static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
{
        unsigned int i;

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

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

        if (desc->l2ptr)
                return 0;

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

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

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

static struct arm_smmu_master *
arm_smmu_find_master(struct arm_smmu_device *smmu, u32 sid)
{
        struct rb_node *node;
        struct arm_smmu_stream *stream;

        lockdep_assert_held(&smmu->streams_mutex);

        node = smmu->streams.rb_node;
        while (node) {
                stream = rb_entry(node, struct arm_smmu_stream, node);
                if (stream->id < sid)
                        node = node->rb_right;
                else if (stream->id > sid)
                        node = node->rb_left;
                else
                        return stream->master;
        }

        return NULL;
}

/* IRQ and event handlers */
static int arm_smmu_handle_evt(struct arm_smmu_device *smmu, u64 *evt)
{
        int ret;
        u32 reason;
        u32 perm = 0;
        struct arm_smmu_master *master;
        bool ssid_valid = evt[0] & EVTQ_0_SSV;
        u32 sid = FIELD_GET(EVTQ_0_SID, evt[0]);
        struct iommu_fault_event fault_evt = { };
        struct iommu_fault *flt = &fault_evt.fault;

        switch (FIELD_GET(EVTQ_0_ID, evt[0])) {
        case EVT_ID_TRANSLATION_FAULT:
                reason = IOMMU_FAULT_REASON_PTE_FETCH;
                break;
        case EVT_ID_ADDR_SIZE_FAULT:
                reason = IOMMU_FAULT_REASON_OOR_ADDRESS;
                break;
        case EVT_ID_ACCESS_FAULT:
                reason = IOMMU_FAULT_REASON_ACCESS;
                break;
        case EVT_ID_PERMISSION_FAULT:
                reason = IOMMU_FAULT_REASON_PERMISSION;
                break;
        default:
                return -EOPNOTSUPP;
        }

        /* Stage-2 is always pinned at the moment */
        if (evt[1] & EVTQ_1_S2)
                return -EFAULT;

        if (evt[1] & EVTQ_1_RnW)
                perm |= IOMMU_FAULT_PERM_READ;
        else
                perm |= IOMMU_FAULT_PERM_WRITE;

        if (evt[1] & EVTQ_1_InD)
                perm |= IOMMU_FAULT_PERM_EXEC;

        if (evt[1] & EVTQ_1_PnU)
                perm |= IOMMU_FAULT_PERM_PRIV;

        if (evt[1] & EVTQ_1_STALL) {
                flt->type = IOMMU_FAULT_PAGE_REQ;
                flt->prm = (struct iommu_fault_page_request) {
                        .flags = IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE,
                        .grpid = FIELD_GET(EVTQ_1_STAG, evt[1]),
                        .perm = perm,
                        .addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
                };

                if (ssid_valid) {
                        flt->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
                        flt->prm.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
                }
        } else {
                flt->type = IOMMU_FAULT_DMA_UNRECOV;
                flt->event = (struct iommu_fault_unrecoverable) {
                        .reason = reason,
                        .flags = IOMMU_FAULT_UNRECOV_ADDR_VALID,
                        .perm = perm,
                        .addr = FIELD_GET(EVTQ_2_ADDR, evt[2]),
                };

                if (ssid_valid) {
                        flt->event.flags |= IOMMU_FAULT_UNRECOV_PASID_VALID;
                        flt->event.pasid = FIELD_GET(EVTQ_0_SSID, evt[0]);
                }
        }

        mutex_lock(&smmu->streams_mutex);
        master = arm_smmu_find_master(smmu, sid);
        if (!master) {
                ret = -EINVAL;
                goto out_unlock;
        }

        ret = iommu_report_device_fault(master->dev, &fault_evt);
        if (ret && flt->type == IOMMU_FAULT_PAGE_REQ) {
                /* Nobody cared, abort the access */
                struct iommu_page_response resp = {
                        .pasid          = flt->prm.pasid,
                        .grpid          = flt->prm.grpid,
                        .code           = IOMMU_PAGE_RESP_FAILURE,
                };
                arm_smmu_page_response(master->dev, &fault_evt, &resp);
        }

out_unlock:
        mutex_unlock(&smmu->streams_mutex);
        return ret;
}

static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
{
        int i, ret;
        struct arm_smmu_device *smmu = dev;
        struct arm_smmu_queue *q = &smmu->evtq.q;
        struct arm_smmu_ll_queue *llq = &q->llq;
        static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
                                      DEFAULT_RATELIMIT_BURST);
        u64 evt[EVTQ_ENT_DWORDS];

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

                        ret = arm_smmu_handle_evt(smmu, evt);
                        if (!ret || !__ratelimit(&rs))
                                continue;

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

                }

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

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

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

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

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

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

                arm_smmu_cmdq_issue_cmd(smmu, &cmd);
        }
}

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

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

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

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

static int arm_smmu_device_disable(struct arm_smmu_device *smmu);

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

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

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

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

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

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

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

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

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

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

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

        if (active & GERROR_CMDQ_ERR)
                arm_smmu_cmdq_skip_err(smmu);

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

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

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

        return IRQ_HANDLED;
}

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

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

        /*
         * ATS and PASID:
         *
         * If substream_valid is clear, the PCIe TLP is sent without a PASID
         * prefix. In that case all ATC entries within the address range are
         * invalidated, including those that were requested with a PASID! There
         * is no way to invalidate only entries without PASID.
         *
         * When using STRTAB_STE_1_S1DSS_SSID0 (reserving CD 0 for non-PASID
         * traffic), translation requests without PASID create ATC entries
         * without PASID, which must be invalidated with substream_valid clear.
         * This has the unpleasant side-effect of invalidating all PASID-tagged
         * ATC entries within the address range.
         */
        *cmd = (struct arm_smmu_cmdq_ent) {
                .opcode                 = CMDQ_OP_ATC_INV,
                .substream_valid        = !!ssid,
                .atc.ssid               = ssid,
        };

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

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

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

        page_start      &= ~span_mask;

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

static int arm_smmu_atc_inv_master(struct arm_smmu_master *master)
{
        int i;
        struct arm_smmu_cmdq_ent cmd;
        struct arm_smmu_cmdq_batch cmds = {};

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

        for (i = 0; i < master->num_streams; i++) {
                cmd.atc.sid = master->streams[i].id;
                arm_smmu_cmdq_batch_add(master->smmu, &cmds, &cmd);
        }

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

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

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

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

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

        cmds.num = 0;

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

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

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

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

        /*
         * NOTE: when io-pgtable is in non-strict mode, we may get here with
         * PTEs previously cleared by unmaps on the current CPU not yet visible
         * to the SMMU. We are relying on the dma_wmb() implicit during cmd
         * insertion to guarantee those are observed before the TLBI. Do be
         * careful, 007.
         */
        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                arm_smmu_tlb_inv_asid(smmu, smmu_domain->s1_cfg.cd.asid);
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S12_VMALL;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
                arm_smmu_cmdq_issue_cmd_with_sync(smmu, &cmd);
        }
        arm_smmu_atc_inv_domain(smmu_domain, 0, 0, 0);
}

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

        if (!size)
                return;

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

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

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

                num_pages = size >> tg;
        }

        cmds.num = 0;

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

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

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

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

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

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

static void arm_smmu_tlb_inv_range_domain(unsigned long iova, size_t size,
                                          size_t granule, bool leaf,
                                          struct arm_smmu_domain *smmu_domain)
{
        struct arm_smmu_cmdq_ent cmd = {
                .tlbi = {
                        .leaf   = leaf,
                },
        };

        if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
                cmd.opcode      = smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
                                  CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA;
                cmd.tlbi.asid   = smmu_domain->s1_cfg.cd.asid;
        } else {
                cmd.opcode      = CMDQ_OP_TLBI_S2_IPA;
                cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
        }
        __arm_smmu_tlb_inv_range(&cmd, iova, size, granule, smmu_domain);

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

void arm_smmu_tlb_inv_range_asid(unsigned long iova, size_t size, int asid,
                                 size_t granule, bool leaf,
                                 struct arm_smmu_domain *smmu_domain)
{
        struct arm_smmu_cmdq_ent cmd = {
                .opcode = smmu_domain->smmu->features & ARM_SMMU_FEAT_E2H ?
                          CMDQ_OP_TLBI_EL2_VA : CMDQ_OP_TLBI_NH_VA,
                .tlbi = {
                        .asid   = asid,
                        .leaf   = leaf,
                },
        };

        __arm_smmu_tlb_inv_range(&cmd, iova, size, granule, smmu_domain);
}

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

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

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

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

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

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

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

        /*

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

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

        return &smmu_domain->domain;
}

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

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

        return idx;
}

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

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

        free_io_pgtable_ops(smmu_domain->pgtbl_ops);

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

                /* Prevent SVA from touching the CD while we're freeing it */
                mutex_lock(&arm_smmu_asid_lock);
                if (cfg->cdcfg.cdtab)
                        arm_smmu_free_cd_tables(smmu_domain);
                arm_smmu_free_asid(&cfg->cd);
                mutex_unlock(&arm_smmu_asid_lock);
        } else {
                struct arm_smmu_s2_cfg *cfg = &smmu_domain->s2_cfg;
                if (cfg->vmid)
                        arm_smmu_bitmap_free(smmu->vmid_map, cfg->vmid);
        }

        kfree(smmu_domain);
}

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

        refcount_set(&cfg->cd.refs, 1);

        /* Prevent SVA from modifying the ASID until it is written to the CD */
        mutex_lock(&arm_smmu_asid_lock);
        ret = xa_alloc(&arm_smmu_asid_xa, &asid, &cfg->cd,
                       XA_LIMIT(1, (1 << smmu->asid_bits) - 1), GFP_KERNEL);
        if (ret)
                goto out_unlock;

        cfg->s1cdmax = master->ssid_bits;

        smmu_domain->stall_enabled = master->stall_enabled;

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

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

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

        mutex_unlock(&arm_smmu_asid_lock);
        return 0;

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

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

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

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

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

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

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

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

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

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

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

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

        smmu_domain->pgtbl_ops = pgtbl_ops;
        return 0;
}

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

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

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

        return step;
}

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

        for (i = 0; i < master->num_streams; ++i) {
                u32 sid = master->streams[i].id;
                __le64 *step = arm_smmu_get_step_for_sid(smmu, sid);

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

                arm_smmu_write_strtab_ent(master, sid, step);
        }
}

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

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

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

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

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

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

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

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

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

        if (!master->ats_enabled)
                return;

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

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

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

        pdev = to_pci_dev(master->dev);

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

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

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

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

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

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

        pdev = to_pci_dev(master->dev);

        if (!pdev->pasid_enabled)
                return;

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

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

        if (!smmu_domain)
                return;

        arm_smmu_disable_ats(master);

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

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

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

        if (!fwspec)
                return -ENOENT;

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

        /*
         * Checking that SVA is disabled ensures that this device isn't bound to
         * any mm, and can be safely detached from its old domain. Bonds cannot
         * be removed concurrently since we're holding the group mutex.
         */
        if (arm_smmu_master_sva_enabled(master)) {
                dev_err(dev, "cannot attach - SVA enabled\n");
                return -EBUSY;
        }

        arm_smmu_detach_dev(master);

        mutex_lock(&smmu_domain->init_mutex);

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

        master->domain = smmu_domain;

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

        arm_smmu_install_ste_for_dev(master);

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

        arm_smmu_enable_ats(master);

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

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

        if (!ops)
                return -ENODEV;

        return ops->map_pages(ops, iova, paddr, pgsize, pgcount, prot, gfp, mapped);
}

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

        if (!ops)
                return 0;

        return ops->unmap_pages(ops, iova, pgsize, pgcount, gather);
}

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

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

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

        if (!gather->pgsize)
                return;

        arm_smmu_tlb_inv_range_domain(gather->start,
                                      gather->end - gather->start + 1,
                                      gather->pgsize, true, smmu_domain);
}

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

        if (!ops)
                return 0;

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

static struct platform_driver arm_smmu_driver;

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

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

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

        return sid < limit;
}

static int arm_smmu_insert_master(struct arm_smmu_device *smmu,
                                  struct arm_smmu_master *master)
{
        int i;
        int ret = 0;
        struct arm_smmu_stream *new_stream, *cur_stream;
        struct rb_node **new_node, *parent_node = NULL;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);

        master->streams = kcalloc(fwspec->num_ids, sizeof(*master->streams),
                                  GFP_KERNEL);
        if (!master->streams)
                return -ENOMEM;
        master->num_streams = fwspec->num_ids;

        mutex_lock(&smmu->streams_mutex);
        for (i = 0; i < fwspec->num_ids; i++) {
                u32 sid = fwspec->ids[i];

                new_stream = &master->streams[i];
                new_stream->id = sid;
                new_stream->master = master;

                /*
                 * Check the SIDs are in range of the SMMU and our stream table
                 */
                if (!arm_smmu_sid_in_range(smmu, sid)) {
                        ret = -ERANGE;
                        break;
                }

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

                /* Insert into SID tree */
                new_node = &(smmu->streams.rb_node);
                while (*new_node) {
                        cur_stream = rb_entry(*new_node, struct arm_smmu_stream,
                                              node);
                        parent_node = *new_node;
                        if (cur_stream->id > new_stream->id) {
                                new_node = &((*new_node)->rb_left);
                        } else if (cur_stream->id < new_stream->id) {
                                new_node = &((*new_node)->rb_right);
                        } else {
                                dev_warn(master->dev,
                                         "stream %u already in tree\n",
                                         cur_stream->id);
                                ret = -EINVAL;
                                break;
                        }
                }
                if (ret)
                        break;

                rb_link_node(&new_stream->node, parent_node, new_node);
                rb_insert_color(&new_stream->node, &smmu->streams);
        }

        if (ret) {
                for (i--; i >= 0; i--)
                        rb_erase(&master->streams[i].node, &smmu->streams);
                kfree(master->streams);
        }
        mutex_unlock(&smmu->streams_mutex);

        return ret;
}

static void arm_smmu_remove_master(struct arm_smmu_master *master)
{
        int i;
        struct arm_smmu_device *smmu = master->smmu;
        struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);

        if (!smmu || !master->streams)
                return;

        mutex_lock(&smmu->streams_mutex);
        for (i = 0; i < fwspec->num_ids; i++)
                rb_erase(&master->streams[i].node, &smmu->streams);
        mutex_unlock(&smmu->streams_mutex);

        kfree(master->streams);
}

static struct iommu_ops arm_smmu_ops;

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

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

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

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

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

        master->dev = dev;
        master->smmu = smmu;
        INIT_LIST_HEAD(&master->bonds);
        dev_iommu_priv_set(dev, master);

        ret = arm_smmu_insert_master(smmu, master);
        if (ret)
                goto err_free_master;

        device_property_read_u32(dev, "pasid-num-bits", &master->ssid_bits);
        master->ssid_bits = min(smmu->ssid_bits, master->ssid_bits);

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

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

        if ((smmu->features & ARM_SMMU_FEAT_STALLS &&
             device_property_read_bool(dev, "dma-can-stall")) ||
            smmu->features & ARM_SMMU_FEAT_STALL_FORCE)
                master->stall_enabled = true;

        return &smmu->iommu;

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

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

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

        master = dev_iommu_priv_get(dev);
        if (WARN_ON(arm_smmu_master_sva_enabled(master)))
                iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
        arm_smmu_detach_dev(master);
        arm_smmu_disable_pasid(master);
        arm_smmu_remove_master(master);
        kfree(master);
        iommu_fwspec_free(dev);
}

static struct iommu_group *arm_smmu_device_group(struct device *dev)
{
        struct iommu_group *group;

        /*
         * We don't support devices sharing stream IDs other than PCI RID
         * aliases, since the necessary ID-to-device lookup becomes rather
         * impractical given a potential sparse 32-bit stream ID space.
         */
        if (dev_is_pci(dev))
                group = pci_device_group(dev);
        else
                group = generic_device_group(dev);

        return group;
}

static int arm_smmu_enable_nesting(struct iommu_domain *domain)
{
        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
        int ret = 0;

        mutex_lock(&smmu_domain->init_mutex);
        if (smmu_domain->smmu)
                ret = -EPERM;
        else
                smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
        mutex_unlock(&smmu_domain->init_mutex);

        return ret;
}

static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
{
        return iommu_fwspec_add_ids(dev, args->args, 1);
}

static void arm_smmu_get_resv_regions(struct device *dev,
                                      struct list_head *head)
{
        struct iommu_resv_region *region;
        int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;

        region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH,
                                         prot, IOMMU_RESV_SW_MSI);
        if (!region)
                return;

        list_add_tail(&region->list, head);

        iommu_dma_get_resv_regions(dev, head);
}

static bool arm_smmu_dev_has_feature(struct device *dev,
                                     enum iommu_dev_features feat)
{
        struct arm_smmu_master *master = dev_iommu_priv_get(dev);

        if (!master)
                return false;

        switch (feat) {
        case IOMMU_DEV_FEAT_IOPF:
                return arm_smmu_master_iopf_supported(master);
        case IOMMU_DEV_FEAT_SVA:
                return arm_smmu_master_sva_supported(master);
        default:
                return false;
        }
}

static bool arm_smmu_dev_feature_enabled(struct device *dev,
                                         enum iommu_dev_features feat)
{
        struct arm_smmu_master *master = dev_iommu_priv_get(dev);

        if (!master)
                return false;

        switch (feat) {
        case IOMMU_DEV_FEAT_IOPF:
                return master->iopf_enabled;
        case IOMMU_DEV_FEAT_SVA:
                return arm_smmu_master_sva_enabled(master);
        default:
                return false;
        }
}

static int arm_smmu_dev_enable_feature(struct device *dev,
                                       enum iommu_dev_features feat)
{
        struct arm_smmu_master *master = dev_iommu_priv_get(dev);

        if (!arm_smmu_dev_has_feature(dev, feat))
                return -ENODEV;

        if (arm_smmu_dev_feature_enabled(dev, feat))
                return -EBUSY;

        switch (feat) {
        case IOMMU_DEV_FEAT_IOPF:
                master->iopf_enabled = true;
                return 0;
        case IOMMU_DEV_FEAT_SVA:
                return arm_smmu_master_enable_sva(master);
        default:
                return -EINVAL;
        }
}

static int arm_smmu_dev_disable_feature(struct device *dev,
                                        enum iommu_dev_features feat)
{
        struct arm_smmu_master *master = dev_iommu_priv_get(dev);

        if (!arm_smmu_dev_feature_enabled(dev, feat))
                return -EINVAL;

        switch (feat) {
        case IOMMU_DEV_FEAT_IOPF:
                if (master->sva_enabled)
                        return -EBUSY;
                master->iopf_enabled = false;
                return 0;
        case IOMMU_DEV_FEAT_SVA:
                return arm_smmu_master_disable_sva(master);
        default:
                return -EINVAL;
        }
}

static struct iommu_ops arm_smmu_ops = {
        .capable                = arm_smmu_capable,
        .domain_alloc           = arm_smmu_domain_alloc,
        .domain_free            = arm_smmu_domain_free,
        .attach_dev             = arm_smmu_attach_dev,
        .map_pages              = arm_smmu_map_pages,
        .unmap_pages            = arm_smmu_unmap_pages,
        .flush_iotlb_all        = arm_smmu_flush_iotlb_all,
        .iotlb_sync             = arm_smmu_iotlb_sync,
        .iova_to_phys           = arm_smmu_iova_to_phys,
        .probe_device           = arm_smmu_probe_device,
        .release_device         = arm_smmu_release_device,
        .device_group           = arm_smmu_device_group,
        .enable_nesting         = arm_smmu_enable_nesting,
        .of_xlate               = arm_smmu_of_xlate,
        .get_resv_regions       = arm_smmu_get_resv_regions,
        .put_resv_regions       = generic_iommu_put_resv_regions,
        .dev_has_feat           = arm_smmu_dev_has_feature,
        .dev_feat_enabled       = arm_smmu_dev_feature_enabled,
        .dev_enable_feat        = arm_smmu_dev_enable_feature,
        .dev_disable_feat       = arm_smmu_dev_disable_feature,
        .sva_bind               = arm_smmu_sva_bind,
        .sva_unbind             = arm_smmu_sva_unbind,
        .sva_get_pasid          = arm_smmu_sva_get_pasid,
        .page_response          = arm_smmu_page_response,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
        .owner                  = THIS_MODULE,
};

/* Probing and initialisation functions */
static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
                                   struct arm_smmu_queue *q,
                                   void __iomem *page,
                                   unsigned long prod_off,
                                   unsigned long cons_off,
                                   size_t dwords, const char *name)
{
        size_t qsz;

        do {
                qsz = ((1 << q->llq.max_n_shift) * dwords) << 3;
                q->base = dmam_alloc_coherent(smmu->dev, qsz, &q->base_dma,
                                              GFP_KERNEL);
                if (q->base || qsz < PAGE_SIZE)
                        break;

                q->llq.max_n_shift--;
        } while (1);

        if (!q->base) {
                dev_err(smmu->dev,
                        "failed to allocate queue (0x%zx bytes) for %s\n",
                        qsz, name);
                return -ENOMEM;
        }

        if (!WARN_ON(q->base_dma & (qsz - 1))) {
                dev_info(smmu->dev, "allocated %u entries for %s\n",
                         1 << q->llq.max_n_shift, name);
        }

        q->prod_reg     = page + prod_off;
        q->cons_reg     = page + cons_off;
        q->ent_dwords   = dwords;

        q->q_base  = Q_BASE_RWA;
        q->q_base |= q->base_dma & Q_BASE_ADDR_MASK;
        q->q_base |= FIELD_PREP(Q_BASE_LOG2SIZE, q->llq.max_n_shift);

        q->llq.prod = q->llq.cons = 0;
        return 0;
}

static void arm_smmu_cmdq_free_bitmap(void *data)
{
        unsigned long *bitmap = data;
        bitmap_free(bitmap);
}

static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
{
        int ret = 0;
        struct arm_smmu_cmdq *cmdq = &smmu->cmdq;
        unsigned int nents = 1 << cmdq->q.llq.max_n_shift;
        atomic_long_t *bitmap;

        atomic_set(&cmdq->owner_prod, 0);
        atomic_set(&cmdq->lock, 0);

        bitmap = (atomic_long_t *)bitmap_zalloc(nents, GFP_KERNEL);
        if (!bitmap) {
                dev_err(smmu->dev, "failed to allocate cmdq bitmap\n");
                ret = -ENOMEM;
        } else {
                cmdq->valid_map = bitmap;
                devm_add_action(smmu->dev, arm_smmu_cmdq_free_bitmap, bitmap);
        }

        return ret;
}

static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
{
        int ret;

        /* cmdq */
        ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, smmu->base,
                                      ARM_SMMU_CMDQ_PROD, ARM_SMMU_CMDQ_CONS,
                                      CMDQ_ENT_DWORDS, "cmdq");
        if (ret)
                return ret;

        ret = arm_smmu_cmdq_init(smmu);
        if (ret)
                return ret;

        /* evtq */
        ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q, smmu->page1,
                                      ARM_SMMU_EVTQ_PROD, ARM_SMMU_EVTQ_CONS,
                                      EVTQ_ENT_DWORDS, "evtq");
        if (ret)
                return ret;

        if ((smmu->features & ARM_SMMU_FEAT_SVA) &&
            (smmu->features & ARM_SMMU_FEAT_STALLS)) {
                smmu->evtq.iopf = iopf_queue_alloc(dev_name(smmu->dev));
                if (!smmu->evtq.iopf)
                        return -ENOMEM;
        }

        /* priq */
        if (!(smmu->features & ARM_SMMU_FEAT_PRI))
                return 0;

        return arm_smmu_init_one_queue(smmu, &smmu->priq.q, smmu->page1,
                                       ARM_SMMU_PRIQ_PROD, ARM_SMMU_PRIQ_CONS,
                                       PRIQ_ENT_DWORDS, "priq");
}

static int arm_smmu_init_l1_strtab(struct arm_smmu_device *smmu)
{
        unsigned int i;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
        size_t size = sizeof(*cfg->l1_desc) * cfg->num_l1_ents;
        void *strtab = smmu->strtab_cfg.strtab;

        cfg->l1_desc = devm_kzalloc(smmu->dev, size, GFP_KERNEL);
        if (!cfg->l1_desc)
                return -ENOMEM;

        for (i = 0; i < cfg->num_l1_ents; ++i) {
                arm_smmu_write_strtab_l1_desc(strtab, &cfg->l1_desc[i]);
                strtab += STRTAB_L1_DESC_DWORDS << 3;
        }

        return 0;
}

static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu)
{
        void *strtab;
        u64 reg;
        u32 size, l1size;
        struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;

        /* Calculate the L1 size, capped to the SIDSIZE. */
        size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3);