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>

1 files changed, 33 insertions, 11 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_mem.c b/drivers/gpu/drm/nouveau/nouveau_mem.c
index 6832c4c969a3..134fedbb7669 100644
--- 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);