drm/nvc0/vram: support non-uniform memory size per controller

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

drivers/gpu/drm/nouveau/nvc0_vram.c

@@ -106,12 +106,50 @@ nvc0_vram_init(struct drm_device *dev)
 	struct nouveau_vram_engine *vram = &dev_priv->engine.vram;
 	const u32 rsvd_head = ( 256 * 1024) >> 12; /* vga memory */
 	const u32 rsvd_tail = (1024 * 1024) >> 12; /* vbios etc */
-	u32 length;
+	u32 parts = nv_rd32(dev, 0x121c74);
+	u32 bsize = nv_rd32(dev, 0x10f20c);
+	u32 offset, length;
+	bool uniform = true;
+	int ret, i;
 
-	dev_priv->vram_size  = nv_rd32(dev, 0x10f20c) << 20;
-	dev_priv->vram_size *= nv_rd32(dev, 0x121c74);
+	NV_DEBUG(dev, "0x100800: 0x%08x\n", nv_rd32(dev, 0x100800));
+	NV_DEBUG(dev, "parts 0x%08x bcast_mem_amount 0x%08x\n", parts, bsize);
 
-	length = (dev_priv->vram_size >> 12) - rsvd_head - rsvd_tail;
+	/* read amount of vram attached to each memory controller */
+	for (i = 0; i < parts; i++) {
+		u32 psize = nv_rd32(dev, 0x11020c + (i * 0x1000));
+		if (psize != bsize) {
+			if (psize < bsize)
+				bsize = psize;
+			uniform = false;
+		}
+
+		NV_DEBUG(dev, "%d: mem_amount 0x%08x\n", i, psize);
+
+		dev_priv->vram_size += (u64)psize << 20;
+	}
+
+	/* if all controllers have the same amount attached, there's no holes */
+	if (uniform) {
+		offset = rsvd_head;
+		length = (dev_priv->vram_size >> 12) - rsvd_head - rsvd_tail;
+		return nouveau_mm_init(&vram->mm, offset, length, 1);
+	}
 
-	return nouveau_mm_init(&vram->mm, rsvd_head, length, 1);
+	/* otherwise, address lowest common amount from 0GiB */
+	ret = nouveau_mm_init(&vram->mm, rsvd_head, (bsize << 8) * parts, 1);
+	if (ret)
+		return ret;
+
+	/* and the rest starting from (8GiB + common_size) */
+	offset = (0x0200000000ULL >> 12) + (bsize << 8);
+	length = (dev_priv->vram_size >> 12) - (bsize << 8) - rsvd_tail;
+
+	ret = nouveau_mm_init(&vram->mm, offset, length, 0);
+	if (ret) {
+		nouveau_mm_fini(&vram->mm);
+		return ret;
+	}
+
+	return 0;
 }