// SPDX-License-Identifier: MIT
/*
 * Copyright © 2021-2023 Intel Corporation
 */

#include "xe_mmio.h"

#include <linux/delay.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/minmax.h>
#include <linux/pci.h>

#include <drm/drm_managed.h>
#include <drm/drm_print.h>

#include "regs/xe_bars.h"
#include "xe_device.h"
#include "xe_gt_sriov_vf.h"
#include "xe_sriov.h"
#include "xe_trace.h"
#include "xe_wa.h"

#include "generated/xe_device_wa_oob.h"

static void tiles_fini(void *arg)
{
        struct xe_device *xe = arg;
        struct xe_tile *tile;
        int id;

        for_each_remote_tile(tile, xe, id)
                tile->mmio.regs = NULL;
}

/*
 * On multi-tile devices, partition the BAR space for MMIO on each tile,
 * possibly accounting for register override on the number of tiles available.
 * tile_mmio_size contains both the tile's 4MB register space, as well as
 * additional space for the GTT and other (possibly unused) regions).
 * Resulting memory layout is like below:
 *
 * .----------------------. <- tile_count * tile_mmio_size
 * |         ....         |
 * |----------------------| <- 2 * tile_mmio_size
 * |   tile1 GTT + other  |
 * |----------------------| <- 1 * tile_mmio_size + 4MB
 * |   tile1->mmio.regs   |
 * |----------------------| <- 1 * tile_mmio_size
 * |   tile0 GTT + other  |
 * |----------------------| <- 4MB
 * |   tile0->mmio.regs   |
 * '----------------------' <- 0MB
 */
static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)
{
        struct xe_tile *tile;
        u8 id;

        /*
         * Nothing to be done as tile 0 has already been setup earlier with the
         * entire BAR mapped - see xe_mmio_probe_early()
         */
        if (xe->info.tile_count == 1)
                return;

        for_each_remote_tile(tile, xe, id)
                xe_mmio_init(&tile->mmio, tile, xe->mmio.regs + id * tile_mmio_size, SZ_4M);
}

int xe_mmio_probe_tiles(struct xe_device *xe)
{
        size_t tile_mmio_size = SZ_16M;

        mmio_multi_tile_setup(xe, tile_mmio_size);

        return devm_add_action_or_reset(xe->drm.dev, tiles_fini, xe);
}

static void mmio_fini(void *arg)
{
        struct xe_device *xe = arg;
        struct xe_tile *root_tile = xe_device_get_root_tile(xe);

        pci_iounmap(to_pci_dev(xe->drm.dev), xe->mmio.regs);
        xe->mmio.regs = NULL;
        root_tile->mmio.regs = NULL;
}

int xe_mmio_probe_early(struct xe_device *xe)
{
        struct xe_tile *root_tile = xe_device_get_root_tile(xe);
        struct pci_dev *pdev = to_pci_dev(xe->drm.dev);

        /*
         * Map the entire BAR.
         * The first 16MB of the BAR, belong to the root tile, and include:
         * registers (0-4MB), reserved space (4MB-8MB) and GGTT (8MB-16MB).
         */
        xe->mmio.size = pci_resource_len(pdev, GTTMMADR_BAR);
        xe->mmio.regs = pci_iomap(pdev, GTTMMADR_BAR, 0);
        if (!xe->mmio.regs) {
                drm_err(&xe->drm, "failed to map registers\n");
                return -EIO;
        }

        /* Setup first tile; other tiles (if present) will be setup later. */
        xe_mmio_init(&root_tile->mmio, root_tile, xe->mmio.regs, SZ_4M);

        return devm_add_action_or_reset(xe->drm.dev, mmio_fini, xe);
}
ALLOW_ERROR_INJECTION(xe_mmio_probe_early, ERRNO); /* See xe_pci_probe() */

/**
 * xe_mmio_init() - Initialize an MMIO instance
 * @mmio: Pointer to the MMIO instance to initialize
 * @tile: The tile to which the MMIO region belongs
 * @ptr: Pointer to the start of the MMIO region
 * @size: The size of the MMIO region in bytes
 *
 * This is a convenience function for minimal initialization of struct xe_mmio.
 */
void xe_mmio_init(struct xe_mmio *mmio, struct xe_tile *tile, void __iomem *ptr, u32 size)
{
        xe_tile_assert(tile, size <= XE_REG_ADDR_MAX);

        mmio->regs = ptr;
        mmio->regs_size = size;
        mmio->tile = tile;
}

static void mmio_flush_pending_writes(struct xe_mmio *mmio)
{
#define DUMMY_REG_OFFSET        0x130030
        int i;

        if (!XE_DEVICE_WA(mmio->tile->xe, 15015404425))
                return;

        /* 4 dummy writes */
        for (i = 0; i < 4; i++)
                writel(0, mmio->regs + DUMMY_REG_OFFSET);
}

u8 xe_mmio_read8(struct xe_mmio *mmio, struct xe_reg reg)
{
        u32 addr = xe_mmio_adjusted_addr(mmio, reg.addr);
        u8 val;

        mmio_flush_pending_writes(mmio);

        val = readb(mmio->regs + addr);
        trace_xe_reg_rw(mmio, false, addr, val, sizeof(val));

        return val;
}

u16 xe_mmio_read16(struct xe_mmio *mmio, struct xe_reg reg)
{
        u32 addr = xe_mmio_adjusted_addr(mmio, reg.addr);
        u16 val;

        mmio_flush_pending_writes(mmio);

        val = readw(mmio->regs + addr);
        trace_xe_reg_rw(mmio, false, addr, val, sizeof(val));

        return val;
}

void xe_mmio_write32(struct xe_mmio *mmio, struct xe_reg reg, u32 val)
{
        u32 addr = xe_mmio_adjusted_addr(mmio, reg.addr);

        trace_xe_reg_rw(mmio, true, addr, val, sizeof(val));

        if (!reg.vf && IS_SRIOV_VF(mmio->tile->xe))
                xe_gt_sriov_vf_write32(mmio->sriov_vf_gt ?:
                                       mmio->tile->primary_gt, reg, val);
        else
                writel(val, mmio->regs + addr);
}

u32 xe_mmio_read32(struct xe_mmio *mmio, struct xe_reg reg)
{
        u32 addr = xe_mmio_adjusted_addr(mmio, reg.addr);
        u32 val;

        mmio_flush_pending_writes(mmio);

        if (!reg.vf && IS_SRIOV_VF(mmio->tile->xe))
                val = xe_gt_sriov_vf_read32(mmio->sriov_vf_gt ?:
                                            mmio->tile->primary_gt, reg);
        else
                val = readl(mmio->regs + addr);

        trace_xe_reg_rw(mmio, false, addr, val, sizeof(val));

        return val;
}

u32 xe_mmio_rmw32(struct xe_mmio *mmio, struct xe_reg reg, u32 clr, u32 set)
{
        u32 old, reg_val;

        old = xe_mmio_read32(mmio, reg);
        reg_val = (old & ~clr) | set;
        xe_mmio_write32(mmio, reg, reg_val);

        return old;
}

int xe_mmio_write32_and_verify(struct xe_mmio *mmio,
                               struct xe_reg reg, u32 val, u32 mask, u32 eval)
{
        u32 reg_val;

        xe_mmio_write32(mmio, reg, val);
        reg_val = xe_mmio_read32(mmio, reg);

        return (reg_val & mask) != eval ? -EINVAL : 0;
}

bool xe_mmio_in_range(const struct xe_mmio *mmio,
                      const struct xe_mmio_range *range,
                      struct xe_reg reg)
{
        u32 addr = xe_mmio_adjusted_addr(mmio, reg.addr);

        return range && addr >= range->start && addr <= range->end;
}

/**
 * xe_mmio_read64_2x32() - Read a 64-bit register as two 32-bit reads
 * @mmio: MMIO target
 * @reg: register to read value from
 *
 * Although Intel GPUs have some 64-bit registers, the hardware officially
 * only supports GTTMMADR register reads of 32 bits or smaller.  Even if
 * a readq operation may return a reasonable value, that violation of the
 * spec shouldn't be relied upon and all 64-bit register reads should be
 * performed as two 32-bit reads of the upper and lower dwords.
 *
 * When reading registers that may be changing (such as
 * counters), a rollover of the lower dword between the two 32-bit reads
 * can be problematic.  This function attempts to ensure the upper dword has
 * stabilized before returning the 64-bit value.
 *
 * Note that because this function may re-read the register multiple times
 * while waiting for the value to stabilize it should not be used to read
 * any registers where read operations have side effects.
 *
 * Returns the value of the 64-bit register.
 */
u64 xe_mmio_read64_2x32(struct xe_mmio *mmio, struct xe_reg reg)
{
        struct xe_reg reg_udw = { .addr = reg.addr + 0x4 };
        u32 ldw, udw, oldudw, retries;

        /*
         * The two dwords of a 64-bit register can never straddle the offset
         * adjustment cutoff.
         */
        xe_tile_assert(mmio->tile, !in_range(mmio->adj_limit, reg.addr + 1, 7));

        oldudw = xe_mmio_read32(mmio, reg_udw);
        for (retries = 5; retries; --retries) {
                ldw = xe_mmio_read32(mmio, reg);
                udw = xe_mmio_read32(mmio, reg_udw);

                if (udw == oldudw)
                        break;

                oldudw = udw;
        }

        drm_WARN(&mmio->tile->xe->drm, retries == 0,
                 "64-bit read of %#x did not stabilize\n", reg.addr);

        return (u64)udw << 32 | ldw;
}

static int __xe_mmio_wait32(struct xe_mmio *mmio, struct xe_reg reg, u32 mask, u32 val,
                            u32 timeout_us, u32 *out_val, bool atomic, bool expect_match)
{
        ktime_t cur = ktime_get_raw();
        const ktime_t end = ktime_add_us(cur, timeout_us);
        int ret = -ETIMEDOUT;
        s64 wait = 10;
        u32 read;
        bool check;

        for (;;) {
                read = xe_mmio_read32(mmio, reg);

                check = (read & mask) == val;
                if (!expect_match)
                        check = !check;

                if (check) {
                        ret = 0;
                        break;
                }

                cur = ktime_get_raw();
                if (!ktime_before(cur, end))
                        break;

                if (ktime_after(ktime_add_us(cur, wait), end))
                        wait = ktime_us_delta(end, cur);

                if (atomic)
                        udelay(wait);
                else
                        usleep_range(wait, wait << 1);
                wait <<= 1;
        }

        if (ret != 0) {
                read = xe_mmio_read32(mmio, reg);

                check = (read & mask) == val;
                if (!expect_match)
                        check = !check;

                if (check)
                        ret = 0;
        }

        if (out_val)
                *out_val = read;

        return ret;
}

/**
 * xe_mmio_wait32() - Wait for a register to match the desired masked value
 * @mmio: MMIO target
 * @reg: register to read value from
 * @mask: mask to be applied to the value read from the register
 * @val: desired value after applying the mask
 * @timeout_us: time out after this period of time. Wait logic tries to be
 * smart, applying an exponential backoff until @timeout_us is reached.
 * @out_val: if not NULL, points where to store the last unmasked value
 * @atomic: needs to be true if calling from an atomic context
 *
 * This function polls for the desired masked value and returns zero on success
 * or -ETIMEDOUT if timed out.
 *
 * Note that @timeout_us represents the minimum amount of time to wait before
 * giving up. The actual time taken by this function can be a little more than
 * @timeout_us for different reasons, specially in non-atomic contexts. Thus,
 * it is possible that this function succeeds even after @timeout_us has passed.
 */
int xe_mmio_wait32(struct xe_mmio *mmio, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
                   u32 *out_val, bool atomic)
{
        return __xe_mmio_wait32(mmio, reg, mask, val, timeout_us, out_val, atomic, true);
}

/**
 * xe_mmio_wait32_not() - Wait for a register to return anything other than the given masked value
 * @mmio: MMIO target
 * @reg: register to read value from
 * @mask: mask to be applied to the value read from the register
 * @val: value not to be matched after applying the mask
 * @timeout_us: time out after this period of time
 * @out_val: if not NULL, points where to store the last unmasked value
 * @atomic: needs to be true if calling from an atomic context
 *
 * This function works exactly like xe_mmio_wait32() with the exception that
 * @val is expected not to be matched.
 */
int xe_mmio_wait32_not(struct xe_mmio *mmio, struct xe_reg reg, u32 mask, u32 val, u32 timeout_us,
                       u32 *out_val, bool atomic)
{
        return __xe_mmio_wait32(mmio, reg, mask, val, timeout_us, out_val, atomic, false);
}

#ifdef CONFIG_PCI_IOV
static size_t vf_regs_stride(struct xe_device *xe)
{
        return GRAPHICS_VERx100(xe) > 1200 ? 0x400 : 0x1000;
}

/**
 * xe_mmio_init_vf_view() - Initialize an MMIO instance for accesses like the VF
 * @mmio: the target &xe_mmio to initialize as VF's view
 * @base: the source &xe_mmio to initialize from
 * @vfid: the VF identifier
 */
void xe_mmio_init_vf_view(struct xe_mmio *mmio, const struct xe_mmio *base, unsigned int vfid)
{
        struct xe_tile *tile = base->tile;
        struct xe_device *xe = tile->xe;
        size_t offset = vf_regs_stride(xe) * vfid;

        xe_assert(xe, IS_SRIOV_PF(xe));
        xe_assert(xe, vfid);
        xe_assert(xe, !base->sriov_vf_gt);
        xe_assert(xe, base->regs_size > offset);

        *mmio = *base;
        mmio->regs += offset;
        mmio->regs_size -= offset;
}
#endif