/*
 * Copyright 2008 Advanced Micro Devices, Inc.
 * Copyright 2008 Red Hat Inc.
 * Copyright 2009 Jerome Glisse.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 *
 * Authors: Dave Airlie
 *          Alex Deucher
 *          Jerome Glisse
 *          Christian König
 */

#include <drm/drm_device.h>
#include <drm/drm_file.h>

#include "radeon.h"

/*
 * Rings
 * Most engines on the GPU are fed via ring buffers.  Ring
 * buffers are areas of GPU accessible memory that the host
 * writes commands into and the GPU reads commands out of.
 * There is a rptr (read pointer) that determines where the
 * GPU is currently reading, and a wptr (write pointer)
 * which determines where the host has written.  When the
 * pointers are equal, the ring is idle.  When the host
 * writes commands to the ring buffer, it increments the
 * wptr.  The GPU then starts fetching commands and executes
 * them until the pointers are equal again.
 */
static void radeon_debugfs_ring_init(struct radeon_device *rdev, struct radeon_ring *ring);

/**
 * radeon_ring_supports_scratch_reg - check if the ring supports
 * writing to scratch registers
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 *
 * Check if a specific ring supports writing to scratch registers (all asics).
 * Returns true if the ring supports writing to scratch regs, false if not.
 */
bool radeon_ring_supports_scratch_reg(struct radeon_device *rdev,
                                      struct radeon_ring *ring)
{
        switch (ring->idx) {
        case RADEON_RING_TYPE_GFX_INDEX:
        case CAYMAN_RING_TYPE_CP1_INDEX:
        case CAYMAN_RING_TYPE_CP2_INDEX:
                return true;
        default:
                return false;
        }
}

/**
 * radeon_ring_free_size - update the free size
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 *
 * Update the free dw slots in the ring buffer (all asics).
 */
void radeon_ring_free_size(struct radeon_device *rdev, struct radeon_ring *ring)
{
        uint32_t rptr = radeon_ring_get_rptr(rdev, ring);

        /* This works because ring_size is a power of 2 */
        ring->ring_free_dw = rptr + (ring->ring_size / 4);
        ring->ring_free_dw -= ring->wptr;
        ring->ring_free_dw &= ring->ptr_mask;
        if (!ring->ring_free_dw) {
                /* this is an empty ring */
                ring->ring_free_dw = ring->ring_size / 4;
                /*  update lockup info to avoid false positive */
                radeon_ring_lockup_update(rdev, ring);
        }
}

/**
 * radeon_ring_alloc - allocate space on the ring buffer
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 * @ndw: number of dwords to allocate in the ring buffer
 *
 * Allocate @ndw dwords in the ring buffer (all asics).
 * Returns 0 on success, error on failure.
 */
int radeon_ring_alloc(struct radeon_device *rdev, struct radeon_ring *ring, unsigned ndw)
{
        int r;

        /* make sure we aren't trying to allocate more space than there is on the ring */
        if (ndw > (ring->ring_size / 4))
                return -ENOMEM;
        /* Align requested size with padding so unlock_commit can
         * pad safely */
        radeon_ring_free_size(rdev, ring);
        ndw = (ndw + ring->align_mask) & ~ring->align_mask;
        while (ndw > (ring->ring_free_dw - 1)) {
                radeon_ring_free_size(rdev, ring);
                if (ndw < ring->ring_free_dw) {
                        break;
                }
                r = radeon_fence_wait_next(rdev, ring->idx);
                if (r)
                        return r;
        }
        ring->count_dw = ndw;
        ring->wptr_old = ring->wptr;
        return 0;
}

/**
 * radeon_ring_lock - lock the ring and allocate space on it
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 * @ndw: number of dwords to allocate in the ring buffer
 *
 * Lock the ring and allocate @ndw dwords in the ring buffer
 * (all asics).
 * Returns 0 on success, error on failure.
 */
int radeon_ring_lock(struct radeon_device *rdev, struct radeon_ring *ring, unsigned ndw)
{
        int r;

        mutex_lock(&rdev->ring_lock);
        r = radeon_ring_alloc(rdev, ring, ndw);
        if (r) {
                mutex_unlock(&rdev->ring_lock);
                return r;
        }
        return 0;
}

/**
 * radeon_ring_commit - tell the GPU to execute the new
 * commands on the ring buffer
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 * @hdp_flush: Whether or not to perform an HDP cache flush
 *
 * Update the wptr (write pointer) to tell the GPU to
 * execute new commands on the ring buffer (all asics).
 */
void radeon_ring_commit(struct radeon_device *rdev, struct radeon_ring *ring,
                        bool hdp_flush)
{
        /* If we are emitting the HDP flush via the ring buffer, we need to
         * do it before padding.
         */
        if (hdp_flush && rdev->asic->ring[ring->idx]->hdp_flush)
                rdev->asic->ring[ring->idx]->hdp_flush(rdev, ring);
        /* We pad to match fetch size */
        while (ring->wptr & ring->align_mask) {
                radeon_ring_write(ring, ring->nop);
        }
        mb();
        /* If we are emitting the HDP flush via MMIO, we need to do it after
         * all CPU writes to VRAM finished.
         */
        if (hdp_flush && rdev->asic->mmio_hdp_flush)
                rdev->asic->mmio_hdp_flush(rdev);
        radeon_ring_set_wptr(rdev, ring);
}

/**
 * radeon_ring_unlock_commit - tell the GPU to execute the new
 * commands on the ring buffer and unlock it
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 * @hdp_flush: Whether or not to perform an HDP cache flush
 *
 * Call radeon_ring_commit() then unlock the ring (all asics).
 */
void radeon_ring_unlock_commit(struct radeon_device *rdev, struct radeon_ring *ring,
                               bool hdp_flush)
{
        radeon_ring_commit(rdev, ring, hdp_flush);
        mutex_unlock(&rdev->ring_lock);
}

/**
 * radeon_ring_undo - reset the wptr
 *
 * @ring: radeon_ring structure holding ring information
 *
 * Reset the driver's copy of the wptr (all asics).
 */
void radeon_ring_undo(struct radeon_ring *ring)
{
        ring->wptr = ring->wptr_old;
}

/**
 * radeon_ring_unlock_undo - reset the wptr and unlock the ring
 *
 * @rdev:       radeon device structure
 * @ring: radeon_ring structure holding ring information
 *
 * Call radeon_ring_undo() then unlock the ring (all asics).
 */
void radeon_ring_unlock_undo(struct radeon_device *rdev, struct radeon_ring *ring)
{
        radeon_ring_undo(ring);
        mutex_unlock(&rdev->ring_lock);
}

/**
 * radeon_ring_lockup_update - update lockup variables
 *
 * @rdev:       radeon device structure
 * @ring: radeon_ring structure holding ring information
 *
 * Update the last rptr value and timestamp (all asics).
 */
void radeon_ring_lockup_update(struct radeon_device *rdev,
                               struct radeon_ring *ring)
{
        atomic_set(&ring->last_rptr, radeon_ring_get_rptr(rdev, ring));
        atomic64_set(&ring->last_activity, jiffies_64);
}

/**
 * radeon_ring_test_lockup() - check if ring is lockedup by recording information
 * @rdev:       radeon device structure
 * @ring:       radeon_ring structure holding ring information
 *
 */
bool radeon_ring_test_lockup(struct radeon_device *rdev, struct radeon_ring *ring)
{
        uint32_t rptr = radeon_ring_get_rptr(rdev, ring);
        uint64_t last = atomic64_read(&ring->last_activity);
        uint64_t elapsed;

        if (rptr != atomic_read(&ring->last_rptr)) {
                /* ring is still working, no lockup */
                radeon_ring_lockup_update(rdev, ring);
                return false;
        }

        elapsed = jiffies_to_msecs(jiffies_64 - last);
        if (radeon_lockup_timeout && elapsed >= radeon_lockup_timeout) {
                dev_err(rdev->dev, "ring %d stalled for more than %llumsec\n",
                        ring->idx, elapsed);
                return true;
        }
        /* give a chance to the GPU ... */
        return false;
}

/**
 * radeon_ring_backup - Back up the content of a ring
 *
 * @rdev: radeon_device pointer
 * @ring: the ring we want to back up
 * @data: placeholder for returned commit data
 *
 * Saves all unprocessed commits from a ring, returns the number of dwords saved.
 */
unsigned radeon_ring_backup(struct radeon_device *rdev, struct radeon_ring *ring,
                            uint32_t **data)
{
        unsigned size, ptr, i;

        /* just in case lock the ring */
        mutex_lock(&rdev->ring_lock);
        *data = NULL;

        if (ring->ring_obj == NULL) {
                mutex_unlock(&rdev->ring_lock);
                return 0;
        }

        /* it doesn't make sense to save anything if all fences are signaled */
        if (!radeon_fence_count_emitted(rdev, ring->idx)) {
                mutex_unlock(&rdev->ring_lock);
                return 0;
        }

        /* calculate the number of dw on the ring */
        if (ring->rptr_save_reg)
                ptr = RREG32(ring->rptr_save_reg);
        else if (rdev->wb.enabled)
                ptr = le32_to_cpu(*ring->next_rptr_cpu_addr);
        else {
                /* no way to read back the next rptr */
                mutex_unlock(&rdev->ring_lock);
                return 0;
        }

        size = ring->wptr + (ring->ring_size / 4);
        size -= ptr;
        size &= ring->ptr_mask;
        if (size == 0) {
                mutex_unlock(&rdev->ring_lock);
                return 0;
        }

        /* and then save the content of the ring */
        *data = kvmalloc_array(size, sizeof(uint32_t), GFP_KERNEL);
        if (!*data) {
                mutex_unlock(&rdev->ring_lock);
                return 0;
        }
        for (i = 0; i < size; ++i) {
                (*data)[i] = ring->ring[ptr++];
                ptr &= ring->ptr_mask;
        }

        mutex_unlock(&rdev->ring_lock);
        return size;
}

/**
 * radeon_ring_restore - append saved commands to the ring again
 *
 * @rdev: radeon_device pointer
 * @ring: ring to append commands to
 * @size: number of dwords we want to write
 * @data: saved commands
 *
 * Allocates space on the ring and restore the previously saved commands.
 */
int radeon_ring_restore(struct radeon_device *rdev, struct radeon_ring *ring,
                        unsigned size, uint32_t *data)
{
        int i, r;

        if (!size || !data)
                return 0;

        /* restore the saved ring content */
        r = radeon_ring_lock(rdev, ring, size);
        if (r)
                return r;

        for (i = 0; i < size; ++i) {
                radeon_ring_write(ring, data[i]);
        }

        radeon_ring_unlock_commit(rdev, ring, false);
        kvfree(data);
        return 0;
}

/**
 * radeon_ring_init - init driver ring struct.
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 * @ring_size: size of the ring
 * @rptr_offs: offset of the rptr writeback location in the WB buffer
 * @nop: nop packet for this ring
 *
 * Initialize the driver information for the selected ring (all asics).
 * Returns 0 on success, error on failure.
 */
int radeon_ring_init(struct radeon_device *rdev, struct radeon_ring *ring, unsigned ring_size,
                     unsigned rptr_offs, u32 nop)
{
        int r;

        ring->ring_size = ring_size;
        ring->rptr_offs = rptr_offs;
        ring->nop = nop;
        ring->rdev = rdev;
        /* Allocate ring buffer */
        if (ring->ring_obj == NULL) {
                r = radeon_bo_create(rdev, ring->ring_size, PAGE_SIZE, true,
                                     RADEON_GEM_DOMAIN_GTT, 0, NULL,
                                     NULL, &ring->ring_obj);
                if (r) {
                        dev_err(rdev->dev, "(%d) ring create failed\n", r);
                        return r;
                }
                r = radeon_bo_reserve(ring->ring_obj, false);
                if (unlikely(r != 0))
                        return r;
                r = radeon_bo_pin(ring->ring_obj, RADEON_GEM_DOMAIN_GTT,
                                        &ring->gpu_addr);
                if (r) {
                        radeon_bo_unreserve(ring->ring_obj);
                        dev_err(rdev->dev, "(%d) ring pin failed\n", r);
                        return r;
                }
                r = radeon_bo_kmap(ring->ring_obj,
                                       (void **)&ring->ring);
                radeon_bo_unreserve(ring->ring_obj);
                if (r) {
                        dev_err(rdev->dev, "(%d) ring map failed\n", r);
                        return r;
                }
        }
        ring->ptr_mask = (ring->ring_size / 4) - 1;
        ring->ring_free_dw = ring->ring_size / 4;
        if (rdev->wb.enabled) {
                u32 index = RADEON_WB_RING0_NEXT_RPTR + (ring->idx * 4);
                ring->next_rptr_gpu_addr = rdev->wb.gpu_addr + index;
                ring->next_rptr_cpu_addr = &rdev->wb.wb[index/4];
        }
        radeon_debugfs_ring_init(rdev, ring);
        radeon_ring_lockup_update(rdev, ring);
        return 0;
}

/**
 * radeon_ring_fini - tear down the driver ring struct.
 *
 * @rdev: radeon_device pointer
 * @ring: radeon_ring structure holding ring information
 *
 * Tear down the driver information for the selected ring (all asics).
 */
void radeon_ring_fini(struct radeon_device *rdev, struct radeon_ring *ring)
{
        int r;
        struct radeon_bo *ring_obj;

        mutex_lock(&rdev->ring_lock);
        ring_obj = ring->ring_obj;
        ring->ready = false;
        ring->ring = NULL;
        ring->ring_obj = NULL;
        mutex_unlock(&rdev->ring_lock);

        if (ring_obj) {
                r = radeon_bo_reserve(ring_obj, false);
                if (likely(r == 0)) {
                        radeon_bo_kunmap(ring_obj);
                        radeon_bo_unpin(ring_obj);
                        radeon_bo_unreserve(ring_obj);
                }
                radeon_bo_unref(&ring_obj);
        }
}

/*
 * Debugfs info
 */
#if defined(CONFIG_DEBUG_FS)

static int radeon_debugfs_ring_info_show(struct seq_file *m, void *unused)
{
        struct radeon_ring *ring = (struct radeon_ring *) m->private;
        struct radeon_device *rdev = ring->rdev;

        uint32_t rptr, wptr, rptr_next;
        unsigned count, i, j;

        radeon_ring_free_size(rdev, ring);
        count = (ring->ring_size / 4) - ring->ring_free_dw;

        wptr = radeon_ring_get_wptr(rdev, ring);
        seq_printf(m, "wptr: 0x%08x [%5d]\n",
                   wptr, wptr);

        rptr = radeon_ring_get_rptr(rdev, ring);
        seq_printf(m, "rptr: 0x%08x [%5d]\n",
                   rptr, rptr);

        if (ring->rptr_save_reg) {
                rptr_next = RREG32(ring->rptr_save_reg);
                seq_printf(m, "rptr next(0x%04x): 0x%08x [%5d]\n",
                           ring->rptr_save_reg, rptr_next, rptr_next);
        } else
                rptr_next = ~0;

        seq_printf(m, "driver's copy of the wptr: 0x%08x [%5d]\n",
                   ring->wptr, ring->wptr);
        seq_printf(m, "last semaphore signal addr : 0x%016llx\n",
                   ring->last_semaphore_signal_addr);
        seq_printf(m, "last semaphore wait addr   : 0x%016llx\n",
                   ring->last_semaphore_wait_addr);
        seq_printf(m, "%u free dwords in ring\n", ring->ring_free_dw);
        seq_printf(m, "%u dwords in ring\n", count);

        if (!ring->ring)
                return 0;

        /* print 8 dw before current rptr as often it's the last executed
         * packet that is the root issue
         */
        i = (rptr + ring->ptr_mask + 1 - 32) & ring->ptr_mask;
        for (j = 0; j <= (count + 32); j++) {
                seq_printf(m, "r[%5d]=0x%08x", i, ring->ring[i]);
                if (rptr == i)
                        seq_puts(m, " *");
                if (rptr_next == i)
                        seq_puts(m, " #");
                seq_puts(m, "\n");
                i = (i + 1) & ring->ptr_mask;
        }
        return 0;
}

DEFINE_SHOW_ATTRIBUTE(radeon_debugfs_ring_info);

static const char *radeon_debugfs_ring_idx_to_name(uint32_t ridx)
{
        switch (ridx) {
        case RADEON_RING_TYPE_GFX_INDEX:
                return "radeon_ring_gfx";
        case CAYMAN_RING_TYPE_CP1_INDEX:
                return "radeon_ring_cp1";
        case CAYMAN_RING_TYPE_CP2_INDEX:
                return "radeon_ring_cp2";
        case R600_RING_TYPE_DMA_INDEX:
                return "radeon_ring_dma1";
        case CAYMAN_RING_TYPE_DMA1_INDEX:
                return "radeon_ring_dma2";
        case R600_RING_TYPE_UVD_INDEX:
                return "radeon_ring_uvd";
        case TN_RING_TYPE_VCE1_INDEX:
                return "radeon_ring_vce1";
        case TN_RING_TYPE_VCE2_INDEX:
                return "radeon_ring_vce2";
        default:
                return NULL;

        }
}
#endif

static void radeon_debugfs_ring_init(struct radeon_device *rdev, struct radeon_ring *ring)
{
#if defined(CONFIG_DEBUG_FS)
        const char *ring_name = radeon_debugfs_ring_idx_to_name(ring->idx);
        struct dentry *root = rdev->ddev->primary->debugfs_root;

        if (ring_name)
                debugfs_create_file(ring_name, 0444, root, ring,
                                    &radeon_debugfs_ring_info_fops);

#endif
}