via_dma.c

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/* via_dma.c -- DMA support for the VIA Unichrome/Pro
 *
 * Copyright 2003 Tungsten Graphics, Inc., Cedar Park, Texas.
 * All Rights Reserved.
 *
 * Copyright 2004 Digeo, Inc., Palo Alto, CA, U.S.A.
 * All Rights Reserved.
 *
 * Copyright 2004 The Unichrome project.
 * All Rights Reserved.
 *
 * 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, sub license,
 * 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 (including the
 * next paragraph) 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 NON-INFRINGEMENT. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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:
 *    Tungsten Graphics,
 *    Erdi Chen,
 *    Thomas Hellstrom.
 */

#include <drm/drmP.h>
#include <drm/via_drm.h>
#include "via_drv.h"
#include "via_3d_reg.h"

#define CMDBUF_ALIGNMENT_SIZE   (0x100)
#define CMDBUF_ALIGNMENT_MASK   (0x0ff)

/* defines for VIA 3D registers */
#define VIA_REG_STATUS          0x400
#define VIA_REG_TRANSET         0x43C
#define VIA_REG_TRANSPACE       0x440

/* VIA_REG_STATUS(0x400): Engine Status */
#define VIA_CMD_RGTR_BUSY       0x00000080  /* Command Regulator is busy */
#define VIA_2D_ENG_BUSY         0x00000001  /* 2D Engine is busy */
#define VIA_3D_ENG_BUSY         0x00000002  /* 3D Engine is busy */
#define VIA_VR_QUEUE_BUSY       0x00020000  /* Virtual Queue is busy */

#define SetReg2DAGP(nReg, nData) {              \
    *((uint32_t *)(vb)) = ((nReg) >> 2) | HALCYON_HEADER1;  \
    *((uint32_t *)(vb) + 1) = (nData);          \
    vb = ((uint32_t *)vb) + 2;              \
    dev_priv->dma_low += 8;                 \
}

#define via_flush_write_combine() DRM_MEMORYBARRIER()

#define VIA_OUT_RING_QW(w1, w2) do {        \
    *vb++ = (w1);               \
    *vb++ = (w2);               \
    dev_priv->dma_low += 8;         \
} while (0)

static void via_cmdbuf_start(drm_via_private_t *dev_priv);
static void via_cmdbuf_pause(drm_via_private_t *dev_priv);
static void via_cmdbuf_reset(drm_via_private_t *dev_priv);
static void via_cmdbuf_rewind(drm_via_private_t *dev_priv);
static int via_wait_idle(drm_via_private_t *dev_priv);
static void via_pad_cache(drm_via_private_t *dev_priv, int qwords);

/*
 * Free space in command buffer.
 */

static uint32_t via_cmdbuf_space(drm_via_private_t *dev_priv)
{
    uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    uint32_t hw_addr = *(dev_priv->hw_addr_ptr) - agp_base;

    return ((hw_addr <= dev_priv->dma_low) ?
        (dev_priv->dma_high + hw_addr - dev_priv->dma_low) :
        (hw_addr - dev_priv->dma_low));
}

/*
 * How much does the command regulator lag behind?
 */

static uint32_t via_cmdbuf_lag(drm_via_private_t *dev_priv)
{
    uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    uint32_t hw_addr = *(dev_priv->hw_addr_ptr) - agp_base;

    return ((hw_addr <= dev_priv->dma_low) ?
        (dev_priv->dma_low - hw_addr) :
        (dev_priv->dma_wrap + dev_priv->dma_low - hw_addr));
}

/*
 * Check that the given size fits in the buffer, otherwise wait.
 */

static inline int
via_cmdbuf_wait(drm_via_private_t *dev_priv, unsigned int size)
{
    uint32_t agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    uint32_t cur_addr, hw_addr, next_addr;
    volatile uint32_t *hw_addr_ptr;
    uint32_t count;
    hw_addr_ptr = dev_priv->hw_addr_ptr;
    cur_addr = dev_priv->dma_low;
    next_addr = cur_addr + size + 512 * 1024;
    count = 1000000;
    do {
        hw_addr = *hw_addr_ptr - agp_base;
        if (count-- == 0) {
            DRM_ERROR
                ("via_cmdbuf_wait timed out hw %x cur_addr %x next_addr %x\n",
                 hw_addr, cur_addr, next_addr);
            return -1;
        }
        if  ((cur_addr < hw_addr) && (next_addr >= hw_addr))
            msleep(1);
    } while ((cur_addr < hw_addr) && (next_addr >= hw_addr));
    return 0;
}

/*
 * Checks whether buffer head has reach the end. Rewind the ring buffer
 * when necessary.
 *
 * Returns virtual pointer to ring buffer.
 */

static inline uint32_t *via_check_dma(drm_via_private_t * dev_priv,
                      unsigned int size)
{
    if ((dev_priv->dma_low + size + 4 * CMDBUF_ALIGNMENT_SIZE) >
        dev_priv->dma_high) {
        via_cmdbuf_rewind(dev_priv);
    }
    if (via_cmdbuf_wait(dev_priv, size) != 0)
        return NULL;

    return (uint32_t *) (dev_priv->dma_ptr + dev_priv->dma_low);
}

int via_dma_cleanup(struct drm_device *dev)
{
    if (dev->dev_private) {
        drm_via_private_t *dev_priv =
            (drm_via_private_t *) dev->dev_private;

        if (dev_priv->ring.virtual_start) {
            via_cmdbuf_reset(dev_priv);

            drm_core_ioremapfree(&dev_priv->ring.map, dev);
            dev_priv->ring.virtual_start = NULL;
        }

    }

    return 0;
}

static int via_initialize(struct drm_device *dev,
              drm_via_private_t *dev_priv,
              drm_via_dma_init_t *init)
{
    if (!dev_priv || !dev_priv->mmio) {
        DRM_ERROR("via_dma_init called before via_map_init\n");
        return -EFAULT;
    }

    if (dev_priv->ring.virtual_start != NULL) {
        DRM_ERROR("called again without calling cleanup\n");
        return -EFAULT;
    }

    if (!dev->agp || !dev->agp->base) {
        DRM_ERROR("called with no agp memory available\n");
        return -EFAULT;
    }

    if (dev_priv->chipset == VIA_DX9_0) {
        DRM_ERROR("AGP DMA is not supported on this chip\n");
        return -EINVAL;
    }

    dev_priv->ring.map.offset = dev->agp->base + init->offset;
    dev_priv->ring.map.size = init->size;
    dev_priv->ring.map.type = 0;
    dev_priv->ring.map.flags = 0;
    dev_priv->ring.map.mtrr = 0;

    drm_core_ioremap(&dev_priv->ring.map, dev);

    if (dev_priv->ring.map.handle == NULL) {
        via_dma_cleanup(dev);
        DRM_ERROR("can not ioremap virtual address for"
              " ring buffer\n");
        return -ENOMEM;
    }

    dev_priv->ring.virtual_start = dev_priv->ring.map.handle;

    dev_priv->dma_ptr = dev_priv->ring.virtual_start;
    dev_priv->dma_low = 0;
    dev_priv->dma_high = init->size;
    dev_priv->dma_wrap = init->size;
    dev_priv->dma_offset = init->offset;
    dev_priv->last_pause_ptr = NULL;
    dev_priv->hw_addr_ptr =
        (volatile uint32_t *)((char *)dev_priv->mmio->handle +
        init->reg_pause_addr);

    via_cmdbuf_start(dev_priv);

    return 0;
}

static int via_dma_init(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
    drm_via_private_t *dev_priv = (drm_via_private_t *) dev->dev_private;
    drm_via_dma_init_t *init = data;
    int retcode = 0;

    switch (init->func) {
    case VIA_INIT_DMA:
        if (!DRM_SUSER(DRM_CURPROC))
            retcode = -EPERM;
        else
            retcode = via_initialize(dev, dev_priv, init);
        break;
    case VIA_CLEANUP_DMA:
        if (!DRM_SUSER(DRM_CURPROC))
            retcode = -EPERM;
        else
            retcode = via_dma_cleanup(dev);
        break;
    case VIA_DMA_INITIALIZED:
        retcode = (dev_priv->ring.virtual_start != NULL) ?
            0 : -EFAULT;
        break;
    default:
        retcode = -EINVAL;
        break;
    }

    return retcode;
}

static int via_dispatch_cmdbuffer(struct drm_device *dev, drm_via_cmdbuffer_t *cmd)
{
    drm_via_private_t *dev_priv;
    uint32_t *vb;
    int ret;

    dev_priv = (drm_via_private_t *) dev->dev_private;

    if (dev_priv->ring.virtual_start == NULL) {
        DRM_ERROR("called without initializing AGP ring buffer.\n");
        return -EFAULT;
    }

    if (cmd->size > VIA_PCI_BUF_SIZE)
        return -ENOMEM;

    if (DRM_COPY_FROM_USER(dev_priv->pci_buf, cmd->buf, cmd->size))
        return -EFAULT;

    /*
     * Running this function on AGP memory is dead slow. Therefore
     * we run it on a temporary cacheable system memory buffer and
     * copy it to AGP memory when ready.
     */

    if ((ret =
         via_verify_command_stream((uint32_t *) dev_priv->pci_buf,
                       cmd->size, dev, 1))) {
        return ret;
    }

    vb = via_check_dma(dev_priv, (cmd->size < 0x100) ? 0x102 : cmd->size);
    if (vb == NULL)
        return -EAGAIN;

    memcpy(vb, dev_priv->pci_buf, cmd->size);

    dev_priv->dma_low += cmd->size;

    /*
     * Small submissions somehow stalls the CPU. (AGP cache effects?)
     * pad to greater size.
     */

    if (cmd->size < 0x100)
        via_pad_cache(dev_priv, (0x100 - cmd->size) >> 3);
    via_cmdbuf_pause(dev_priv);

    return 0;
}

int via_driver_dma_quiescent(struct drm_device *dev)
{
    drm_via_private_t *dev_priv = dev->dev_private;

    if (!via_wait_idle(dev_priv))
        return -EBUSY;
    return 0;
}

static int via_flush_ioctl(struct drm_device *dev, void *data, struct drm_file *file_priv)
{

    LOCK_TEST_WITH_RETURN(dev, file_priv);

    return via_driver_dma_quiescent(dev);
}

static int via_cmdbuffer(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
    drm_via_cmdbuffer_t *cmdbuf = data;
    int ret;

    LOCK_TEST_WITH_RETURN(dev, file_priv);

    DRM_DEBUG("buf %p size %lu\n", cmdbuf->buf, cmdbuf->size);

    ret = via_dispatch_cmdbuffer(dev, cmdbuf);
    return ret;
}

static int via_dispatch_pci_cmdbuffer(struct drm_device *dev,
                      drm_via_cmdbuffer_t *cmd)
{
    drm_via_private_t *dev_priv = dev->dev_private;
    int ret;

    if (cmd->size > VIA_PCI_BUF_SIZE)
        return -ENOMEM;
    if (DRM_COPY_FROM_USER(dev_priv->pci_buf, cmd->buf, cmd->size))
        return -EFAULT;

    if ((ret =
         via_verify_command_stream((uint32_t *) dev_priv->pci_buf,
                       cmd->size, dev, 0))) {
        return ret;
    }

    ret =
        via_parse_command_stream(dev, (const uint32_t *)dev_priv->pci_buf,
                     cmd->size);
    return ret;
}

static int via_pci_cmdbuffer(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
    drm_via_cmdbuffer_t *cmdbuf = data;
    int ret;

    LOCK_TEST_WITH_RETURN(dev, file_priv);

    DRM_DEBUG("buf %p size %lu\n", cmdbuf->buf, cmdbuf->size);

    ret = via_dispatch_pci_cmdbuffer(dev, cmdbuf);
    return ret;
}

static inline uint32_t *via_align_buffer(drm_via_private_t *dev_priv,
                     uint32_t * vb, int qw_count)
{
    for (; qw_count > 0; --qw_count)
        VIA_OUT_RING_QW(HC_DUMMY, HC_DUMMY);
    return vb;
}

/*
 * This function is used internally by ring buffer management code.
 *
 * Returns virtual pointer to ring buffer.
 */
static inline uint32_t *via_get_dma(drm_via_private_t *dev_priv)
{
    return (uint32_t *) (dev_priv->dma_ptr + dev_priv->dma_low);
}

/*
 * Hooks a segment of data into the tail of the ring-buffer by
 * modifying the pause address stored in the buffer itself. If
 * the regulator has already paused, restart it.
 */
static int via_hook_segment(drm_via_private_t *dev_priv,
                uint32_t pause_addr_hi, uint32_t pause_addr_lo,
                int no_pci_fire)
{
    int paused, count;
    volatile uint32_t *paused_at = dev_priv->last_pause_ptr;
    uint32_t reader, ptr;
    uint32_t diff;

    paused = 0;
    via_flush_write_combine();
    (void) *(volatile uint32_t *)(via_get_dma(dev_priv) - 1);

    *paused_at = pause_addr_lo;
    via_flush_write_combine();
    (void) *paused_at;

    reader = *(dev_priv->hw_addr_ptr);
    ptr = ((volatile char *)paused_at - dev_priv->dma_ptr) +
        dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;

    dev_priv->last_pause_ptr = via_get_dma(dev_priv) - 1;

    /*
     * If there is a possibility that the command reader will
     * miss the new pause address and pause on the old one,
     * In that case we need to program the new start address
     * using PCI.
     */

    diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
    count = 10000000;
    while (diff == 0 && count--) {
        paused = (VIA_READ(0x41c) & 0x80000000);
        if (paused)
            break;
        reader = *(dev_priv->hw_addr_ptr);
        diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
    }

    paused = VIA_READ(0x41c) & 0x80000000;

    if (paused && !no_pci_fire) {
        reader = *(dev_priv->hw_addr_ptr);
        diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
        diff &= (dev_priv->dma_high - 1);
        if (diff != 0 && diff < (dev_priv->dma_high >> 1)) {
            DRM_ERROR("Paused at incorrect address. "
                  "0x%08x, 0x%08x 0x%08x\n",
                  ptr, reader, dev_priv->dma_diff);
        } else if (diff == 0) {
            /*
             * There is a concern that these writes may stall the PCI bus
             * if the GPU is not idle. However, idling the GPU first
             * doesn't make a difference.
             */

            VIA_WRITE(VIA_REG_TRANSET, (HC_ParaType_PreCR << 16));
            VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_hi);
            VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_lo);
            VIA_READ(VIA_REG_TRANSPACE);
        }
    }
    return paused;
}

static int via_wait_idle(drm_via_private_t *dev_priv)
{
    int count = 10000000;

    while (!(VIA_READ(VIA_REG_STATUS) & VIA_VR_QUEUE_BUSY) && --count)
        ;

    while (count && (VIA_READ(VIA_REG_STATUS) &
               (VIA_CMD_RGTR_BUSY | VIA_2D_ENG_BUSY |
                VIA_3D_ENG_BUSY)))
        --count;
    return count;
}

static uint32_t *via_align_cmd(drm_via_private_t *dev_priv, uint32_t cmd_type,
                   uint32_t addr, uint32_t *cmd_addr_hi,
                   uint32_t *cmd_addr_lo, int skip_wait)
{
    uint32_t agp_base;
    uint32_t cmd_addr, addr_lo, addr_hi;
    uint32_t *vb;
    uint32_t qw_pad_count;

    if (!skip_wait)
        via_cmdbuf_wait(dev_priv, 2 * CMDBUF_ALIGNMENT_SIZE);

    vb = via_get_dma(dev_priv);
    VIA_OUT_RING_QW(HC_HEADER2 | ((VIA_REG_TRANSET >> 2) << 12) |
            (VIA_REG_TRANSPACE >> 2), HC_ParaType_PreCR << 16);
    agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    qw_pad_count = (CMDBUF_ALIGNMENT_SIZE >> 3) -
        ((dev_priv->dma_low & CMDBUF_ALIGNMENT_MASK) >> 3);

    cmd_addr = (addr) ? addr :
        agp_base + dev_priv->dma_low - 8 + (qw_pad_count << 3);
    addr_lo = ((HC_SubA_HAGPBpL << 24) | (cmd_type & HC_HAGPBpID_MASK) |
           (cmd_addr & HC_HAGPBpL_MASK));
    addr_hi = ((HC_SubA_HAGPBpH << 24) | (cmd_addr >> 24));

    vb = via_align_buffer(dev_priv, vb, qw_pad_count - 1);
    VIA_OUT_RING_QW(*cmd_addr_hi = addr_hi, *cmd_addr_lo = addr_lo);
    return vb;
}

static void via_cmdbuf_start(drm_via_private_t *dev_priv)
{
    uint32_t pause_addr_lo, pause_addr_hi;
    uint32_t start_addr, start_addr_lo;
    uint32_t end_addr, end_addr_lo;
    uint32_t command;
    uint32_t agp_base;
    uint32_t ptr;
    uint32_t reader;
    int count;

    dev_priv->dma_low = 0;

    agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    start_addr = agp_base;
    end_addr = agp_base + dev_priv->dma_high;

    start_addr_lo = ((HC_SubA_HAGPBstL << 24) | (start_addr & 0xFFFFFF));
    end_addr_lo = ((HC_SubA_HAGPBendL << 24) | (end_addr & 0xFFFFFF));
    command = ((HC_SubA_HAGPCMNT << 24) | (start_addr >> 24) |
           ((end_addr & 0xff000000) >> 16));

    dev_priv->last_pause_ptr =
        via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0,
              &pause_addr_hi, &pause_addr_lo, 1) - 1;

    via_flush_write_combine();
    (void) *(volatile uint32_t *)dev_priv->last_pause_ptr;

    VIA_WRITE(VIA_REG_TRANSET, (HC_ParaType_PreCR << 16));
    VIA_WRITE(VIA_REG_TRANSPACE, command);
    VIA_WRITE(VIA_REG_TRANSPACE, start_addr_lo);
    VIA_WRITE(VIA_REG_TRANSPACE, end_addr_lo);

    VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_hi);
    VIA_WRITE(VIA_REG_TRANSPACE, pause_addr_lo);
    DRM_WRITEMEMORYBARRIER();
    VIA_WRITE(VIA_REG_TRANSPACE, command | HC_HAGPCMNT_MASK);
    VIA_READ(VIA_REG_TRANSPACE);

    dev_priv->dma_diff = 0;

    count = 10000000;
    while (!(VIA_READ(0x41c) & 0x80000000) && count--);

    reader = *(dev_priv->hw_addr_ptr);
    ptr = ((volatile char *)dev_priv->last_pause_ptr - dev_priv->dma_ptr) +
        dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;

    /*
     * This is the difference between where we tell the
     * command reader to pause and where it actually pauses.
     * This differs between hw implementation so we need to
     * detect it.
     */

    dev_priv->dma_diff = ptr - reader;
}

static void via_pad_cache(drm_via_private_t *dev_priv, int qwords)
{
    uint32_t *vb;

    via_cmdbuf_wait(dev_priv, qwords + 2);
    vb = via_get_dma(dev_priv);
    VIA_OUT_RING_QW(HC_HEADER2, HC_ParaType_NotTex << 16);
    via_align_buffer(dev_priv, vb, qwords);
}

static inline void via_dummy_bitblt(drm_via_private_t *dev_priv)
{
    uint32_t *vb = via_get_dma(dev_priv);
    SetReg2DAGP(0x0C, (0 | (0 << 16)));
    SetReg2DAGP(0x10, 0 | (0 << 16));
    SetReg2DAGP(0x0, 0x1 | 0x2000 | 0xAA000000);
}

static void via_cmdbuf_jump(drm_via_private_t *dev_priv)
{
    uint32_t agp_base;
    uint32_t pause_addr_lo, pause_addr_hi;
    uint32_t jump_addr_lo, jump_addr_hi;
    volatile uint32_t *last_pause_ptr;
    uint32_t dma_low_save1, dma_low_save2;

    agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
    via_align_cmd(dev_priv, HC_HAGPBpID_JUMP, 0, &jump_addr_hi,
              &jump_addr_lo, 0);

    dev_priv->dma_wrap = dev_priv->dma_low;

    /*
     * Wrap command buffer to the beginning.
     */

    dev_priv->dma_low = 0;
    if (via_cmdbuf_wait(dev_priv, CMDBUF_ALIGNMENT_SIZE) != 0)
        DRM_ERROR("via_cmdbuf_jump failed\n");

    via_dummy_bitblt(dev_priv);
    via_dummy_bitblt(dev_priv);

    last_pause_ptr =
        via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
              &pause_addr_lo, 0) - 1;
    via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
              &pause_addr_lo, 0);

    *last_pause_ptr = pause_addr_lo;
    dma_low_save1 = dev_priv->dma_low;

    /*
     * Now, set a trap that will pause the regulator if it tries to rerun the old
     * command buffer. (Which may happen if via_hook_segment detecs a command regulator pause
     * and reissues the jump command over PCI, while the regulator has already taken the jump
     * and actually paused at the current buffer end).
     * There appears to be no other way to detect this condition, since the hw_addr_pointer
     * does not seem to get updated immediately when a jump occurs.
     */

    last_pause_ptr =
        via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
                  &pause_addr_lo, 0) - 1;
    via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
              &pause_addr_lo, 0);
    *last_pause_ptr = pause_addr_lo;

    dma_low_save2 = dev_priv->dma_low;
    dev_priv->dma_low = dma_low_save1;
    via_hook_segment(dev_priv, jump_addr_hi, jump_addr_lo, 0);
    dev_priv->dma_low = dma_low_save2;
    via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
}


static void via_cmdbuf_rewind(drm_via_private_t *dev_priv)
{
    via_cmdbuf_jump(dev_priv);
}

static void via_cmdbuf_flush(drm_via_private_t *dev_priv, uint32_t cmd_type)
{
    uint32_t pause_addr_lo, pause_addr_hi;

    via_align_cmd(dev_priv, cmd_type, 0, &pause_addr_hi, &pause_addr_lo, 0);
    via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
}

static void via_cmdbuf_pause(drm_via_private_t *dev_priv)
{
    via_cmdbuf_flush(dev_priv, HC_HAGPBpID_PAUSE);
}

static void via_cmdbuf_reset(drm_via_private_t *dev_priv)
{
    via_cmdbuf_flush(dev_priv, HC_HAGPBpID_STOP);
    via_wait_idle(dev_priv);
}

/*
 * User interface to the space and lag functions.
 */

static int via_cmdbuf_size(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
    drm_via_cmdbuf_size_t *d_siz = data;
    int ret = 0;
    uint32_t tmp_size, count;
    drm_via_private_t *dev_priv;

    DRM_DEBUG("\n");
    LOCK_TEST_WITH_RETURN(dev, file_priv);

    dev_priv = (drm_via_private_t *) dev->dev_private;

    if (dev_priv->ring.virtual_start == NULL) {
        DRM_ERROR("called without initializing AGP ring buffer.\n");
        return -EFAULT;
    }

    count = 1000000;
    tmp_size = d_siz->size;
    switch (d_siz->func) {
    case VIA_CMDBUF_SPACE:
        while (((tmp_size = via_cmdbuf_space(dev_priv)) < d_siz->size)
               && --count) {
            if (!d_siz->wait)
                break;
        }
        if (!count) {
            DRM_ERROR("VIA_CMDBUF_SPACE timed out.\n");
            ret = -EAGAIN;
        }
        break;
    case VIA_CMDBUF_LAG:
        while (((tmp_size = via_cmdbuf_lag(dev_priv)) > d_siz->size)
               && --count) {
            if (!d_siz->wait)
                break;
        }
        if (!count) {
            DRM_ERROR("VIA_CMDBUF_LAG timed out.\n");
            ret = -EAGAIN;
        }
        break;
    default:
        ret = -EFAULT;
    }
    d_siz->size = tmp_size;

    return ret;
}

struct drm_ioctl_desc via_ioctls[] = {
    DRM_IOCTL_DEF_DRV(VIA_ALLOCMEM, via_mem_alloc, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_FREEMEM, via_mem_free, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_AGP_INIT, via_agp_init, DRM_AUTH|DRM_MASTER),
    DRM_IOCTL_DEF_DRV(VIA_FB_INIT, via_fb_init, DRM_AUTH|DRM_MASTER),
    DRM_IOCTL_DEF_DRV(VIA_MAP_INIT, via_map_init, DRM_AUTH|DRM_MASTER),
    DRM_IOCTL_DEF_DRV(VIA_DEC_FUTEX, via_decoder_futex, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_DMA_INIT, via_dma_init, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_CMDBUFFER, via_cmdbuffer, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_FLUSH, via_flush_ioctl, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_PCICMD, via_pci_cmdbuffer, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_CMDBUF_SIZE, via_cmdbuf_size, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_WAIT_IRQ, via_wait_irq, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_DMA_BLIT, via_dma_blit, DRM_AUTH),
    DRM_IOCTL_DEF_DRV(VIA_BLIT_SYNC, via_dma_blit_sync, DRM_AUTH)
};

int via_max_ioctl = DRM_ARRAY_SIZE(via_ioctls);