drm/nv50: improve vram page table construction

This commit changes nouveau to construct PTEs which look very much like
the ones the binary driver creates.

I presume that filling multiple PTEs identically with length flags and
the physical address of the start of a block of VRAM is a hint to the
memory controller that it need not perform additional page table lookups
for that range of addresses.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_mem.c b/drivers/gpu/drm/nouveau/nouveau_mem.c
index 6832c4c..134fedb 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_mem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mem.c
@@ -285,23 +285,45 @@ nv50_mem_vm_bind_linear(struct drm_device *dev, uint64_t virt, uint32_t size,
                        uint32_t flags, uint64_t phys)
 {
        struct drm_nouveau_private *dev_priv = dev->dev_private;
-       unsigned pages;
+       struct nouveau_gpuobj *pgt;
+       unsigned block;
+       int i;
 
-       virt -= dev_priv->vm_vram_base;
-       pages = size >> 16;
+       virt = ((virt - dev_priv->vm_vram_base) >> 16) << 1;
+       size = (size >> 16) << 1;
+       phys |= ((uint64_t)flags << 32) | 1;
 
        dev_priv->engine.instmem.prepare_access(dev, true);
-       while (pages--) {
-               struct nouveau_gpuobj *pt = dev_priv->vm_vram_pt[virt >> 29];
-               unsigned pte = ((virt & 0x1fffffffULL) >> 16) << 1;
-               unsigned offset_h = upper_32_bits(phys) & 0xff;
+       while (size) {
+               unsigned offset_h = upper_32_bits(phys);
                unsigned offset_l = lower_32_bits(phys);
+               unsigned pte, end;
+
+               for (i = 7; i >= 0; i--) {
+                       block = 1 << (i + 1);
+                       if (size >= block && !(virt & (block - 1)))
+                               break;
+               }
+               offset_l |= (i << 7);
+
+               phys += block << 15;
+               size -= block;
 
-               nv_wo32(dev, pt, pte++, offset_l | 1);
-               nv_wo32(dev, pt, pte++, offset_h | flags);
+               while (block) {
+                       pgt = dev_priv->vm_vram_pt[virt >> 14];
+                       pte = virt & 0x3ffe;
 
-               phys += (1 << 16);
-               virt += (1 << 16);
+                       end = pte + block;
+                       if (end > 16384)
+                               end = 16384;
+                       block -= (end - pte);
+                       virt  += (end - pte);
+
+                       while (pte < end) {
+                               nv_wo32(dev, pgt, pte++, offset_l);
+                               nv_wo32(dev, pgt, pte++, offset_h);
+                       }
+               }
        }
        dev_priv->engine.instmem.finish_access(dev);