drm/radeon: fix r600 writeback setup.

This fixes 2 bugs:
1. the AGP calculation wasn't consistent with the PCI(E) calc for the
RPTR_ADDR registers. This consolidates the writes and fixes it up.

2. The scratch address was being incorrectly calculated, this breaks
it out into a lot more linear steps.

Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 22 insertions, 13 deletions

diff --git a/drivers/gpu/drm/radeon/r600_cp.c b/drivers/gpu/drm/radeon/r600_cp.c
index 6f2cc74350c5..04fde35dc21d 100644
--- a/drivers/gpu/drm/radeon/r600_cp.c
+++ b/drivers/gpu/drm/radeon/r600_cp.c
@@ -1630,6 +1630,7 @@ static void r600_cp_init_ring_buffer(struct drm_device *dev,
 {
         struct drm_radeon_master_private *master_priv;
         u32 ring_start;
+        u64 rptr_addr;
 
         if (((dev_priv->flags & RADEON_FAMILY_MASK) >= CHIP_RV770))
                 r700_gfx_init(dev, dev_priv);
@@ -1684,21 +1685,20 @@ static void r600_cp_init_ring_buffer(struct drm_device *dev,
 
 #if __OS_HAS_AGP
         if (dev_priv->flags & RADEON_IS_AGP) {
-                /* XXX */
-                RADEON_WRITE(R600_CP_RB_RPTR_ADDR,
-                             (dev_priv->ring_rptr->offset
-                             - dev->agp->base + dev_priv->gart_vm_start) >> 8);
-                RADEON_WRITE(R600_CP_RB_RPTR_ADDR_HI, 0);
+                rptr_addr = dev_priv->ring_rptr->offset
+                        - dev->agp->base +
+                        dev_priv->gart_vm_start;
         } else
 #endif
         {
-                RADEON_WRITE(R600_CP_RB_RPTR_ADDR,
-                             dev_priv->ring_rptr->offset
-                             - ((unsigned long) dev->sg->virtual)
-                             + dev_priv->gart_vm_start);
-
-                RADEON_WRITE(R600_CP_RB_RPTR_ADDR_HI, 0);
+                rptr_addr = dev_priv->ring_rptr->offset
+                        - ((unsigned long) dev->sg->virtual)
+                        + dev_priv->gart_vm_start;
         }
+        RADEON_WRITE(R600_CP_RB_RPTR_ADDR,
+                     rptr_addr & 0xffffffff);
+        RADEON_WRITE(R600_CP_RB_RPTR_ADDR_HI,
+                     upper_32_bits(rptr_addr));
 
 #ifdef __BIG_ENDIAN
         RADEON_WRITE(R600_CP_RB_CNTL,
@@ -1747,8 +1747,17 @@ static void r600_cp_init_ring_buffer(struct drm_device *dev,
          * We simply put this behind the ring read pointer, this works
          * with PCI GART as well as (whatever kind of) AGP GART
          */
-        RADEON_WRITE(R600_SCRATCH_ADDR, ((RADEON_READ(R600_CP_RB_RPTR_ADDR) << 8)
-                                         + R600_SCRATCH_REG_OFFSET) >> 8);
+        {
+                u64 scratch_addr;
+
+                scratch_addr = RADEON_READ(R600_CP_RB_RPTR_ADDR);
+                scratch_addr |= ((u64)RADEON_READ(R600_CP_RB_RPTR_ADDR_HI)) << 32;
+                scratch_addr += R600_SCRATCH_REG_OFFSET;
+                scratch_addr >>= 8;
+                scratch_addr &= 0xffffffff;
+
+                RADEON_WRITE(R600_SCRATCH_ADDR, (uint32_t)scratch_addr);
+        }
 
         RADEON_WRITE(R600_SCRATCH_UMSK, 0x7);