[sfrench/cifs-2.6.git] / drivers / irqchip / irq-gic-v3-its.c

/*
 * Copyright (C) 2013, 2014 ARM Limited, All Rights Reserved.
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

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

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

#include "irq-gic-common.h"

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

#define RDIST_FLAGS_PROPBASE_NEEDS_FLUSHING     (1 << 0)

static u32 lpi_id_bits;

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

#define LPI_PROP_DEFAULT_PRIO   0xa0

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

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

/*
 * The ITS structure - contains most of the infrastructure, with the
 * top-level MSI domain, the command queue, the collections, and the
 * list of devices writing to it.
 */
struct its_node {
        raw_spinlock_t          lock;
        struct list_head        entry;
        void __iomem            *base;
        phys_addr_t             phys_base;
        struct its_cmd_block    *cmd_base;
        struct its_cmd_block    *cmd_write;
        struct its_baser        tables[GITS_BASER_NR_REGS];
        struct its_collection   *collections;
        struct list_head        its_device_list;
        u64                     flags;
        u32                     ite_size;
        u32                     device_ids;
        int                     numa_node;
        bool                    is_v4;
};

#define ITS_ITT_ALIGN           SZ_256

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

struct event_lpi_map {
        unsigned long           *lpi_map;
        u16                     *col_map;
        irq_hw_number_t         lpi_base;
        int                     nr_lpis;
};

/*
 * The ITS view of a device - belongs to an ITS, a collection, owns an
 * interrupt translation table, and a list of interrupts.
 */
struct its_device {
        struct list_head        entry;
        struct its_node         *its;
        struct event_lpi_map    event_map;
        void                    *itt;
        u32                     nr_ites;
        u32                     device_id;
};

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

/*
 * We have a maximum number of 16 ITSs in the whole system if we're
 * using the ITSList mechanism
 */
#define ITS_LIST_MAX            16

static unsigned long its_list_map;

#define gic_data_rdist()                (raw_cpu_ptr(gic_rdists->rdist))
#define gic_data_rdist_rd_base()        (gic_data_rdist()->rd_base)

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

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

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

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

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

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

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

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

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

                struct {
                        struct its_collection *col;
                } its_invall_cmd;
        };
};

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

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

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

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

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

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

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

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

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

static void its_encode_itt(struct its_cmd_block *cmd, u64 itt_addr)
{
        its_mask_encode(&cmd->raw_cmd[2], itt_addr >> 8, 50, 8);
}

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

static void its_encode_target(struct its_cmd_block *cmd, u64 target_addr)
{
        its_mask_encode(&cmd->raw_cmd[2], target_addr >> 16, 50, 16);
}

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

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

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

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

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

        its_fixup_cmd(cmd);

        return NULL;
}

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

        its_fixup_cmd(cmd);

        return desc->its_mapc_cmd.col;
}

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

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

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

        its_fixup_cmd(cmd);

        return col;
}

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

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

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

        its_fixup_cmd(cmd);

        return col;
}

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

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

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

        its_fixup_cmd(cmd);

        return col;
}

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

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

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

        its_fixup_cmd(cmd);

        return col;
}

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

        its_fixup_cmd(cmd);

        return NULL;
}

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

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

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

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

        return 0;
}

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

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

        cmd = its->cmd_write++;

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

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

        return cmd;
}

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

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

        return its->cmd_write;
}

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

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

        from_idx = its_cmd_ptr_to_offset(its, from);
        to_idx = its_cmd_ptr_to_offset(its, to);

        while (1) {
                rd_idx = readl_relaxed(its->base + GITS_CREADR);

                /* Direct case */
                if (from_idx < to_idx && rd_idx >= to_idx)
                        break;

                /* Wrapped case */
                if (from_idx >= to_idx && rd_idx >= to_idx && rd_idx < from_idx)
                        break;

                count--;
                if (!count) {
                        pr_err_ratelimited("ITS queue timeout\n");
                        return;
                }
                cpu_relax();
                udelay(1);
        }
}

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

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

        its_fixup_cmd(sync_cmd);
}

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

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

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

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

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

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

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

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

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

        its_send_single_command(its, its_build_mapc_cmd, &desc);
}

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

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

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

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

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

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

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

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

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

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

        desc.its_invall_cmd.col = col;

        its_send_single_command(its, its_build_invall_cmd, &desc);
}

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

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

static void lpi_set_config(struct irq_data *d, bool enable)
{
        struct its_device *its_dev = irq_data_get_irq_chip_data(d);
        irq_hw_number_t hwirq = d->hwirq;
        u32 id = its_get_event_id(d);
        u8 *cfg = page_address(gic_rdists->prop_page) + hwirq - 8192;

        if (enable)
                *cfg |= LPI_PROP_ENABLED;
        else
                *cfg &= ~LPI_PROP_ENABLED;

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

static void its_mask_irq(struct irq_data *d)
{
        lpi_set_config(d, false);
}

static void its_unmask_irq(struct irq_data *d)
{
        lpi_set_config(d, true);
}

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

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

        cpu = cpumask_any_and(mask_val, cpu_mask);

        if (cpu >= nr_cpu_ids)
                return -EINVAL;

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

        return IRQ_SET_MASK_OK_DONE;
}

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

        its = its_dev->its;
        addr = its->phys_base + GITS_TRANSLATER;

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

        iommu_dma_map_msi_msg(d->irq, msg);
}

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

/*
 * How we allocate LPIs:
 *
 * The GIC has id_bits bits for interrupt identifiers. From there, we
 * must subtract 8192 which are reserved for SGIs/PPIs/SPIs. Then, as
 * we allocate LPIs by chunks of 32, we can shift the whole thing by 5
 * bits to the right.
 *
 * This gives us (((1UL << id_bits) - 8192) >> 5) possible allocations.
 */
#define IRQS_PER_CHUNK_SHIFT    5
#define IRQS_PER_CHUNK          (1 << IRQS_PER_CHUNK_SHIFT)
#define ITS_MAX_LPI_NRBITS      16 /* 64K LPIs */

static unsigned long *lpi_bitmap;
static u32 lpi_chunks;
static DEFINE_SPINLOCK(lpi_lock);

static int its_lpi_to_chunk(int lpi)
{
        return (lpi - 8192) >> IRQS_PER_CHUNK_SHIFT;
}

static int its_chunk_to_lpi(int chunk)
{
        return (chunk << IRQS_PER_CHUNK_SHIFT) + 8192;
}

static int __init its_lpi_init(u32 id_bits)
{
        lpi_chunks = its_lpi_to_chunk(1UL << id_bits);

        lpi_bitmap = kzalloc(BITS_TO_LONGS(lpi_chunks) * sizeof(long),
                             GFP_KERNEL);
        if (!lpi_bitmap) {
                lpi_chunks = 0;
                return -ENOMEM;
        }

        pr_info("ITS: Allocated %d chunks for LPIs\n", (int)lpi_chunks);
        return 0;
}

static unsigned long *its_lpi_alloc_chunks(int nr_irqs, int *base, int *nr_ids)
{
        unsigned long *bitmap = NULL;
        int chunk_id;
        int nr_chunks;
        int i;

        nr_chunks = DIV_ROUND_UP(nr_irqs, IRQS_PER_CHUNK);

        spin_lock(&lpi_lock);

        do {
                chunk_id = bitmap_find_next_zero_area(lpi_bitmap, lpi_chunks,
                                                      0, nr_chunks, 0);
                if (chunk_id < lpi_chunks)
                        break;

                nr_chunks--;
        } while (nr_chunks > 0);

        if (!nr_chunks)
                goto out;

        bitmap = kzalloc(BITS_TO_LONGS(nr_chunks * IRQS_PER_CHUNK) * sizeof (long),
                         GFP_ATOMIC);
        if (!bitmap)
                goto out;

        for (i = 0; i < nr_chunks; i++)
                set_bit(chunk_id + i, lpi_bitmap);

        *base = its_chunk_to_lpi(chunk_id);
        *nr_ids = nr_chunks * IRQS_PER_CHUNK;

out:
        spin_unlock(&lpi_lock);

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

        return bitmap;
}

static void its_lpi_free(struct event_lpi_map *map)
{
        int base = map->lpi_base;
        int nr_ids = map->nr_lpis;
        int lpi;

        spin_lock(&lpi_lock);

        for (lpi = base; lpi < (base + nr_ids); lpi += IRQS_PER_CHUNK) {
                int chunk = its_lpi_to_chunk(lpi);
                BUG_ON(chunk > lpi_chunks);
                if (test_bit(chunk, lpi_bitmap)) {
                        clear_bit(chunk, lpi_bitmap);
                } else {
                        pr_err("Bad LPI chunk %d\n", chunk);
                }
        }

        spin_unlock(&lpi_lock);

        kfree(map->lpi_map);
        kfree(map->col_map);
}

static int __init its_alloc_lpi_tables(void)
{
        phys_addr_t paddr;

        lpi_id_bits = min_t(u32, gic_rdists->id_bits, ITS_MAX_LPI_NRBITS);
        gic_rdists->prop_page = alloc_pages(GFP_NOWAIT,
                                           get_order(LPI_PROPBASE_SZ));
        if (!gic_rdists->prop_page) {
                pr_err("Failed to allocate PROPBASE\n");
                return -ENOMEM;
        }

        paddr = page_to_phys(gic_rdists->prop_page);
        pr_info("GIC: using LPI property table @%pa\n", &paddr);

        /* Priority 0xa0, Group-1, disabled */
        memset(page_address(gic_rdists->prop_page),
               LPI_PROP_DEFAULT_PRIO | LPI_PROP_GROUP1,
               LPI_PROPBASE_SZ);

        /* Make sure the GIC will observe the written configuration */
        gic_flush_dcache_to_poc(page_address(gic_rdists->prop_page), LPI_PROPBASE_SZ);

        return its_lpi_init(lpi_id_bits);
}

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

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

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

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

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

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

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

        base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
        if (!base)
                return -ENOMEM;

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

        val |=  indirect ? GITS_BASER_INDIRECT : 0x0;

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

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

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

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

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

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

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

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

        return 0;
}

static bool its_parse_baser_device(struct its_node *its, struct its_baser *baser,
                                   u32 psz, u32 *order)
{
        u64 esz = GITS_BASER_ENTRY_SIZE(its_read_baser(its, baser));
        u64 val = GITS_BASER_InnerShareable | GITS_BASER_RaWaWb;
        u32 ids = its->device_ids;
        u32 new_order = *order;
        bool indirect = false;

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

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

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

        *order = new_order;

        return indirect;
}

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

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

static int its_alloc_tables(struct its_node *its)
{
        u64 typer = gic_read_typer(its->base + GITS_TYPER);
        u32 ids = GITS_TYPER_DEVBITS(typer);
        u64 shr = GITS_BASER_InnerShareable;
        u64 cache = GITS_BASER_RaWaWb;
        u32 psz = SZ_64K;
        int err, i;

        if (its->flags & ITS_FLAGS_WORKAROUND_CAVIUM_22375) {
                /*
                * erratum 22375: only alloc 8MB table size
                * erratum 24313: ignore memory access type
                */
                cache   = GITS_BASER_nCnB;
                ids     = 0x14;                 /* 20 bits, 8MB */
        }

        its->device_ids = ids;

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

                if (type == GITS_BASER_TYPE_NONE)
                        continue;

                if (type == GITS_BASER_TYPE_DEVICE)
                        indirect = its_parse_baser_device(its, baser, psz, &order);

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

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

        return 0;
}

static int its_alloc_collections(struct its_node *its)
{
        its->collections = kzalloc(nr_cpu_ids * sizeof(*its->collections),
                                   GFP_KERNEL);
        if (!its->collections)
                return -ENOMEM;

        return 0;
}

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

        /* If we didn't allocate the pending table yet, do it now */
        pend_page = gic_data_rdist()->pend_page;
        if (!pend_page) {
                phys_addr_t paddr;
                /*
                 * The pending pages have to be at least 64kB aligned,
                 * hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below.
                 */
                pend_page = alloc_pages(GFP_NOWAIT | __GFP_ZERO,
                                        get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K)));
                if (!pend_page) {
                        pr_err("Failed to allocate PENDBASE for CPU%d\n",
                               smp_processor_id());
                        return;
                }

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

                paddr = page_to_phys(pend_page);
                pr_info("CPU%d: using LPI pending table @%pa\n",
                        smp_processor_id(), &paddr);
                gic_data_rdist()->pend_page = pend_page;
        }

        /* Disable LPIs */
        val = readl_relaxed(rbase + GICR_CTLR);
        val &= ~GICR_CTLR_ENABLE_LPIS;
        writel_relaxed(val, rbase + GICR_CTLR);

        /*
         * Make sure any change to the table is observable by the GIC.
         */
        dsb(sy);

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

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

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

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

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

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

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

        /* Make sure the GIC has seen the above */
        dsb(sy);
}

static void its_cpu_init_collection(void)
{
        struct its_node *its;
        int cpu;

        spin_lock(&its_lock);
        cpu = smp_processor_id();

        list_for_each_entry(its, &its_nodes, entry) {
                u64 target;

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

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

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

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

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

        spin_unlock(&its_lock);
}

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

        raw_spin_lock_irqsave(&its->lock, flags);

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

        raw_spin_unlock_irqrestore(&its->lock, flags);

        return its_dev;
}

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

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

        return NULL;
}

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

        baser = its_get_baser(its, GITS_BASER_TYPE_DEVICE);

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

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

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

        table = baser->base;

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

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

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

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

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

        return true;
}

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

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

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        /*
         * At least one bit of EventID is being used, hence a minimum
         * of two entries. No, the architecture doesn't let you
         * express an ITT with a single entry.
         */
        nr_ites = max(2UL, roundup_pow_of_two(nvecs));
        sz = nr_ites * its->ite_size;
        sz = max(sz, ITS_ITT_ALIGN) + ITS_ITT_ALIGN - 1;
        itt = kzalloc(sz, GFP_KERNEL);
        lpi_map = its_lpi_alloc_chunks(nvecs, &lpi_base, &nr_lpis);
        if (lpi_map)
                col_map = kzalloc(sizeof(*col_map) * nr_lpis, GFP_KERNEL);

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

        gic_flush_dcache_to_poc(itt, sz);

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

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

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

        return dev;
}

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

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

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

        idx = find_first_zero_bit(dev->event_map.lpi_map,
                                  dev->event_map.nr_lpis);
        if (idx == dev->event_map.nr_lpis)
                return -ENOSPC;

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

        return 0;
}

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

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

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

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

        its_dev = its_create_device(its, dev_id, nvec);
        if (!its_dev)
                return -ENOMEM;

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

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

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

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

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

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

        for (i = 0; i < nr_irqs; i++) {
                err = its_alloc_device_irq(its_dev, &hwirq);
                if (err)
                        return err;

                err = its_irq_gic_domain_alloc(domain, virq + i, hwirq);
                if (err)
                        return err;

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

        return 0;
}

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

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

        /* Bind the LPI to the first possible CPU */
        its_dev->event_map.col_map[event] = cpumask_first(cpu_mask);

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

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

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

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

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

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

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

        /* If all interrupts have been freed, start mopping the floor */
        if (bitmap_empty(its_dev->event_map.lpi_map,
                         its_dev->event_map.nr_lpis)) {
                its_lpi_free(&its_dev->event_map);

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

        irq_domain_free_irqs_parent(domain, virq, nr_irqs);
}

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

static int its_force_quiescent(void __iomem *base)
{
        u32 count = 1000000;    /* 1s */
        u32 val;

        val = readl_relaxed(base + GITS_CTLR);
        /*
         * GIC architecture specification requires the ITS to be both
         * disabled and quiescent for writes to GITS_BASER<n> or
         * GITS_CBASER to not have UNPREDICTABLE results.
         */
        if ((val & GITS_CTLR_QUIESCENT) && !(val & GITS_CTLR_ENABLE))
                return 0;

        /* Disable the generation of all interrupts to this ITS */
        val &= ~GITS_CTLR_ENABLE;
        writel_relaxed(val, base + GITS_CTLR);

        /* Poll GITS_CTLR and wait until ITS becomes quiescent */
        while (1) {
                val = readl_relaxed(base + GITS_CTLR);
                if (val & GITS_CTLR_QUIESCENT)
                        return 0;

                count--;
                if (!count)
                        return -EBUSY;

                cpu_relax();
                udelay(1);
        }
}

static void __maybe_unused its_enable_quirk_cavium_22375(void *data)
{
        struct its_node *its = data;

        its->flags |= ITS_FLAGS_WORKAROUND_CAVIUM_22375;
}

static void __maybe_unused its_enable_quirk_cavium_23144(void *data)
{
        struct its_node *its = data;

        its->flags |= ITS_FLAGS_WORKAROUND_CAVIUM_23144;
}

static void __maybe_unused its_enable_quirk_qdf2400_e0065(void *data)
{
        struct its_node *its = data;

        /* On QDF2400, the size of the ITE is 16Bytes */
        its->ite_size = 16;
}

static const struct gic_quirk its_quirks[] = {
#ifdef CONFIG_CAVIUM_ERRATUM_22375
        {
                .desc   = "ITS: Cavium errata 22375, 24313",
                .iidr   = 0xa100034c,   /* ThunderX pass 1.x */
                .mask   = 0xffff0fff,
                .init   = its_enable_quirk_cavium_22375,
        },
#endif
#ifdef CONFIG_CAVIUM_ERRATUM_23144
        {
                .desc   = "ITS: Cavium erratum 23144",
                .iidr   = 0xa100034c,   /* ThunderX pass 1.x */
                .mask   = 0xffff0fff,
                .init   = its_enable_quirk_cavium_23144,
        },
#endif
#ifdef CONFIG_QCOM_QDF2400_ERRATUM_0065
        {
                .desc   = "ITS: QDF2400 erratum 0065",
                .iidr   = 0x00001070, /* QDF2400 ITS rev 1.x */
                .mask   = 0xffffffff,
                .init   = its_enable_quirk_qdf2400_e0065,
        },
#endif
        {
        }
};

static void its_enable_quirks(struct its_node *its)
{
        u32 iidr = readl_relaxed(its->base + GITS_IIDR);

        gic_enable_quirks(iidr, its_quirks, its);
}

static int its_init_domain(struct fwnode_handle *handle, struct its_node *its)
{
        struct irq_domain *inner_domain;
        struct msi_domain_info *info;

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

        inner_domain = irq_domain_create_tree(handle, &its_domain_ops, its);
        if (!inner_domain) {
                kfree(info);
                return -ENOMEM;
        }

        inner_domain->parent = its_parent;
        irq_domain_update_bus_token(inner_domain, DOMAIN_BUS_NEXUS);
        inner_domain->flags |= IRQ_DOMAIN_FLAG_MSI_REMAP;
        info->ops = &its_msi_domain_ops;
        info->data = its;
        inner_domain->host_data = info;

        return 0;
}

static int __init its_compute_its_list_map(struct resource *res,
                                           void __iomem *its_base)
{
        int its_number;
        u32 ctlr;

        /*
         * This is assumed to be done early enough that we're
         * guaranteed to be single-threaded, hence no
         * locking. Should this change, we should address
         * this.
         */
        its_number = find_first_zero_bit(&its_list_map, ITS_LIST_MAX);
        if (its_number >= ITS_LIST_MAX) {
                pr_err("ITS@%pa: No ITSList entry available!\n",
                       &res->start);
                return -EINVAL;
        }

        ctlr = readl_relaxed(its_base + GITS_CTLR);
        ctlr &= ~GITS_CTLR_ITS_NUMBER;
        ctlr |= its_number << GITS_CTLR_ITS_NUMBER_SHIFT;
        writel_relaxed(ctlr, its_base + GITS_CTLR);
        ctlr = readl_relaxed(its_base + GITS_CTLR);
        if ((ctlr & GITS_CTLR_ITS_NUMBER) != (its_number << GITS_CTLR_ITS_NUMBER_SHIFT)) {
                its_number = ctlr & GITS_CTLR_ITS_NUMBER;
                its_number >>= GITS_CTLR_ITS_NUMBER_SHIFT;
        }

        if (test_and_set_bit(its_number, &its_list_map)) {
                pr_err("ITS@%pa: Duplicate ITSList entry %d\n",
                       &res->start, its_number);
                return -EINVAL;
        }

        return its_number;
}

static int __init its_probe_one(struct resource *res,
                                struct fwnode_handle *handle, int numa_node)
{
        struct its_node *its;
        void __iomem *its_base;
        u32 val, ctlr;
        u64 baser, tmp, typer;
        int err;

        its_base = ioremap(res->start, resource_size(res));
        if (!its_base) {
                pr_warn("ITS@%pa: Unable to map ITS registers\n", &res->start);
                return -ENOMEM;
        }

        val = readl_relaxed(its_base + GITS_PIDR2) & GIC_PIDR2_ARCH_MASK;
        if (val != 0x30 && val != 0x40) {
                pr_warn("ITS@%pa: No ITS detected, giving up\n", &res->start);
                err = -ENODEV;
                goto out_unmap;
        }

        err = its_force_quiescent(its_base);
        if (err) {
                pr_warn("ITS@%pa: Failed to quiesce, giving up\n", &res->start);
                goto out_unmap;
        }

        pr_info("ITS %pR\n", res);

        its = kzalloc(sizeof(*its), GFP_KERNEL);
        if (!its) {
                err = -ENOMEM;
                goto out_unmap;
        }

        raw_spin_lock_init(&its->lock);
        INIT_LIST_HEAD(&its->entry);
        INIT_LIST_HEAD(&its->its_device_list);
        typer = gic_read_typer(its_base + GITS_TYPER);
        its->base = its_base;
        its->phys_base = res->start;
        its->ite_size = GITS_TYPER_ITT_ENTRY_SIZE(typer);
        its->is_v4 = !!(typer & GITS_TYPER_VLPIS);
        if (its->is_v4) {
                if (!(typer & GITS_TYPER_VMOVP)) {
                        err = its_compute_its_list_map(res, its_base);
                        if (err < 0)
                                goto out_free_its;

                        pr_info("ITS@%pa: Using ITS number %d\n",
                                &res->start, err);
                } else {
                        pr_info("ITS@%pa: Single VMOVP capable\n", &res->start);
                }
        }

        its->numa_node = numa_node;

        its->cmd_base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
                                                get_order(ITS_CMD_QUEUE_SZ));
        if (!its->cmd_base) {
                err = -ENOMEM;
                goto out_free_its;
        }
        its->cmd_write = its->cmd_base;

        its_enable_quirks(its);

        err = its_alloc_tables(its);
        if (err)
                goto out_free_cmd;

        err = its_alloc_collections(its);
        if (err)
                goto out_free_tables;

        baser = (virt_to_phys(its->cmd_base)    |
                 GITS_CBASER_RaWaWb             |
                 GITS_CBASER_InnerShareable     |
                 (ITS_CMD_QUEUE_SZ / SZ_4K - 1) |
                 GITS_CBASER_VALID);

        gits_write_cbaser(baser, its->base + GITS_CBASER);
        tmp = gits_read_cbaser(its->base + GITS_CBASER);

        if ((tmp ^ baser) & GITS_CBASER_SHAREABILITY_MASK) {
                if (!(tmp & GITS_CBASER_SHAREABILITY_MASK)) {
                        /*
                         * The HW reports non-shareable, we must
                         * remove the cacheability attributes as
                         * well.
                         */
                        baser &= ~(GITS_CBASER_SHAREABILITY_MASK |
                                   GITS_CBASER_CACHEABILITY_MASK);
                        baser |= GITS_CBASER_nC;
                        gits_write_cbaser(baser, its->base + GITS_CBASER);
                }
                pr_info("ITS: using cache flushing for cmd queue\n");
                its->flags |= ITS_FLAGS_CMDQ_NEEDS_FLUSHING;
        }

        gits_write_cwriter(0, its->base + GITS_CWRITER);
        ctlr = readl_relaxed(its->base + GITS_CTLR);
        writel_relaxed(ctlr | GITS_CTLR_ENABLE, its->base + GITS_CTLR);

        err = its_init_domain(handle, its);
        if (err)
                goto out_free_tables;

        spin_lock(&its_lock);
        list_add(&its->entry, &its_nodes);
        spin_unlock(&its_lock);

        return 0;

out_free_tables:
        its_free_tables(its);
out_free_cmd:
        free_pages((unsigned long)its->cmd_base, get_order(ITS_CMD_QUEUE_SZ));
out_free_its:
        kfree(its);
out_unmap:
        iounmap(its_base);
        pr_err("ITS@%pa: failed probing (%d)\n", &res->start, err);
        return err;
}

static bool gic_rdists_supports_plpis(void)
{
        return !!(gic_read_typer(gic_data_rdist_rd_base() + GICR_TYPER) & GICR_TYPER_PLPIS);
}

int its_cpu_init(void)
{
        if (!list_empty(&its_nodes)) {
                if (!gic_rdists_supports_plpis()) {
                        pr_info("CPU%d: LPIs not supported\n", smp_processor_id());
                        return -ENXIO;
                }
                its_cpu_init_lpis();
                its_cpu_init_collection();
        }

        return 0;
}

static const struct of_device_id its_device_id[] = {
        {       .compatible     = "arm,gic-v3-its",     },
        {},
};

static int __init its_of_probe(struct device_node *node)
{
        struct device_node *np;
        struct resource res;

        for (np = of_find_matching_node(node, its_device_id); np;
             np = of_find_matching_node(np, its_device_id)) {
                if (!of_property_read_bool(np, "msi-controller")) {
                        pr_warn("%pOF: no msi-controller property, ITS ignored\n",
                                np);
                        continue;
                }

                if (of_address_to_resource(np, 0, &res)) {
                        pr_warn("%pOF: no regs?\n", np);
                        continue;
                }

                its_probe_one(&res, &np->fwnode, of_node_to_nid(np));
        }
        return 0;
}

#ifdef CONFIG_ACPI

#define ACPI_GICV3_ITS_MEM_SIZE (SZ_128K)

#if defined(CONFIG_ACPI_NUMA) && (ACPI_CA_VERSION >= 0x20170531)
struct its_srat_map {
        /* numa node id */
        u32     numa_node;
        /* GIC ITS ID */
        u32     its_id;
};

static struct its_srat_map its_srat_maps[MAX_NUMNODES] __initdata;
static int its_in_srat __initdata;

static int __init acpi_get_its_numa_node(u32 its_id)
{
        int i;

        for (i = 0; i < its_in_srat; i++) {
                if (its_id == its_srat_maps[i].its_id)
                        return its_srat_maps[i].numa_node;
        }
        return NUMA_NO_NODE;
}

static int __init gic_acpi_parse_srat_its(struct acpi_subtable_header *header,
                         const unsigned long end)
{
        int node;
        struct acpi_srat_gic_its_affinity *its_affinity;

        its_affinity = (struct acpi_srat_gic_its_affinity *)header;
        if (!its_affinity)
                return -EINVAL;

        if (its_affinity->header.length < sizeof(*its_affinity)) {
                pr_err("SRAT: Invalid header length %d in ITS affinity\n",
                        its_affinity->header.length);
                return -EINVAL;
        }

        if (its_in_srat >= MAX_NUMNODES) {
                pr_err("SRAT: ITS affinity exceeding max count[%d]\n",
                                MAX_NUMNODES);
                return -EINVAL;
        }

        node = acpi_map_pxm_to_node(its_affinity->proximity_domain);

        if (node == NUMA_NO_NODE || node >= MAX_NUMNODES) {
                pr_err("SRAT: Invalid NUMA node %d in ITS affinity\n", node);
                return 0;
        }

        its_srat_maps[its_in_srat].numa_node = node;
        its_srat_maps[its_in_srat].its_id = its_affinity->its_id;
        its_in_srat++;
        pr_info("SRAT: PXM %d -> ITS %d -> Node %d\n",
                its_affinity->proximity_domain, its_affinity->its_id, node);

        return 0;
}

static void __init acpi_table_parse_srat_its(void)
{
        acpi_table_parse_entries(ACPI_SIG_SRAT,
                        sizeof(struct acpi_table_srat),
                        ACPI_SRAT_TYPE_GIC_ITS_AFFINITY,
                        gic_acpi_parse_srat_its, 0);
}
#else
static void __init acpi_table_parse_srat_its(void)      { }
static int __init acpi_get_its_numa_node(u32 its_id) { return NUMA_NO_NODE; }
#endif

static int __init gic_acpi_parse_madt_its(struct acpi_subtable_header *header,
                                          const unsigned long end)
{
        struct acpi_madt_generic_translator *its_entry;
        struct fwnode_handle *dom_handle;
        struct resource res;
        int err;

        its_entry = (struct acpi_madt_generic_translator *)header;
        memset(&res, 0, sizeof(res));
        res.start = its_entry->base_address;
        res.end = its_entry->base_address + ACPI_GICV3_ITS_MEM_SIZE - 1;
        res.flags = IORESOURCE_MEM;

        dom_handle = irq_domain_alloc_fwnode((void *)its_entry->base_address);
        if (!dom_handle) {
                pr_err("ITS@%pa: Unable to allocate GICv3 ITS domain token\n",
                       &res.start);
                return -ENOMEM;
        }

        err = iort_register_domain_token(its_entry->translation_id, dom_handle);
        if (err) {
                pr_err("ITS@%pa: Unable to register GICv3 ITS domain token (ITS ID %d) to IORT\n",
                       &res.start, its_entry->translation_id);
                goto dom_err;
        }

        err = its_probe_one(&res, dom_handle,
                        acpi_get_its_numa_node(its_entry->translation_id));
        if (!err)
                return 0;

        iort_deregister_domain_token(its_entry->translation_id);
dom_err:
        irq_domain_free_fwnode(dom_handle);
        return err;
}

static void __init its_acpi_probe(void)
{
        acpi_table_parse_srat_its();
        acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
                              gic_acpi_parse_madt_its, 0);
}
#else
static void __init its_acpi_probe(void) { }
#endif

int __init its_init(struct fwnode_handle *handle, struct rdists *rdists,
                    struct irq_domain *parent_domain)
{
        struct device_node *of_node;

        its_parent = parent_domain;
        of_node = to_of_node(handle);
        if (of_node)
                its_of_probe(of_node);
        else
                its_acpi_probe();

        if (list_empty(&its_nodes)) {
                pr_warn("ITS: No ITS available, not enabling LPIs\n");
                return -ENXIO;
        }

        gic_rdists = rdists;
        return its_alloc_lpi_tables();
}