drm/nv20-nv40: add memory type detection

NV20/NV30 is partially educated guesswork at this point, based on any
information around about available memory types and a horribly unspeakable
amount of vbios image scouring.  I'm not entirely certain the GDDR3 define
is correct, I have not spotted a single vbios with that value yet (though
it is mentioned in some 1218-using nv4x vbios), but there are reports that
some nv3x did use it..

NV40(100914) confirmed by switching an NV49 to DDR1/DDR2 values and making
sure that the binary driver behaviour showed it had detected DDR1/DDR2
instead of GDDR3 before dying horribly.

NV40(100474) confirmed by doing much the same task as above on an NV44,
except this was *much* easier as changing the values didn't seem to have
any noticable effect on the memory controller aside from changing the
binary driver's behaviour.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -1173,6 +1173,7 @@ extern void nv30_fb_init_tile_region(struct drm_device *dev, int i,
 extern void nv30_fb_free_tile_region(struct drm_device *dev, int i);
 
 /* nv40_fb.c */
+extern int  nv40_fb_vram_init(struct drm_device *dev);
 extern int  nv40_fb_init(struct drm_device *);
 extern void nv40_fb_takedown(struct drm_device *);
 extern void nv40_fb_set_tile_region(struct drm_device *dev, int i);

drivers/gpu/drm/nouveau/nouveau_state.c

@@ -290,7 +290,7 @@ static int nouveau_init_engine_ptrs(struct drm_device *dev)
 		engine->pm.temp_get		= nv40_temp_get;
 		engine->pm.pwm_get		= nv40_pm_pwm_get;
 		engine->pm.pwm_set		= nv40_pm_pwm_set;
-		engine->vram.init		= nv20_fb_vram_init;
+		engine->vram.init		= nv40_fb_vram_init;
 		engine->vram.takedown		= nouveau_stub_takedown;
 		engine->vram.flags_valid	= nouveau_mem_flags_valid;
 		break;

drivers/gpu/drm/nouveau/nv20_fb.c

@@ -100,8 +100,17 @@ int
 nv20_fb_vram_init(struct drm_device *dev)
 {
 	struct drm_nouveau_private *dev_priv = dev->dev_private;
+	u32 mem_size = nv_rd32(dev, 0x10020c);
+	u32 pbus1218 = nv_rd32(dev, 0x001218);
+
+	dev_priv->vram_size = mem_size & 0xff000000;
+	switch (pbus1218 & 0x00000300) {
+	case 0x00000000: dev_priv->vram_type = NV_MEM_TYPE_SDRAM; break;
+	case 0x00000100: dev_priv->vram_type = NV_MEM_TYPE_DDR1; break;
+	case 0x00000200: dev_priv->vram_type = NV_MEM_TYPE_GDDR3; break;
+	case 0x00000300: dev_priv->vram_type = NV_MEM_TYPE_GDDR2; break;
+	}
 
-	dev_priv->vram_size = nv_rd32(dev, 0x10020c) & 0xff000000;
 	return 0;
 }
 

drivers/gpu/drm/nouveau/nv40_fb.c

@@ -71,6 +71,51 @@ nv44_fb_init_gart(struct drm_device *dev)
 	nv_wr32(dev, 0x100800, vinst | 0x00000010);
 }
 
+int
+nv40_fb_vram_init(struct drm_device *dev)
+{
+	struct drm_nouveau_private *dev_priv = dev->dev_private;
+
+	/* 0x001218 is actually present on a few other NV4X I looked at,
+	 * and even contains sane values matching 0x100474.  From looking
+	 * at various vbios images however, this isn't the case everywhere.
+	 * So, I chose to use the same regs I've seen NVIDIA reading around
+	 * the memory detection, hopefully that'll get us the right numbers
+	 */
+	if (dev_priv->chipset == 0x40) {
+		u32 pbus1218 = nv_rd32(dev, 0x001218);
+		switch (pbus1218 & 0x00000300) {
+		case 0x00000000: dev_priv->vram_type = NV_MEM_TYPE_SDRAM; break;
+		case 0x00000100: dev_priv->vram_type = NV_MEM_TYPE_DDR1; break;
+		case 0x00000200: dev_priv->vram_type = NV_MEM_TYPE_GDDR3; break;
+		case 0x00000300: dev_priv->vram_type = NV_MEM_TYPE_DDR2; break;
+		}
+	} else
+	if (dev_priv->chipset == 0x49 || dev_priv->chipset == 0x4b) {
+		u32 pfb914 = nv_rd32(dev, 0x100914);
+		switch (pfb914 & 0x00000003) {
+		case 0x00000000: dev_priv->vram_type = NV_MEM_TYPE_DDR1; break;
+		case 0x00000001: dev_priv->vram_type = NV_MEM_TYPE_DDR2; break;
+		case 0x00000002: dev_priv->vram_type = NV_MEM_TYPE_GDDR3; break;
+		case 0x00000003: break;
+		}
+	} else
+	if (dev_priv->chipset != 0x4e) {
+		u32 pfb474 = nv_rd32(dev, 0x100474);
+		if (pfb474 & 0x00000004)
+			dev_priv->vram_type = NV_MEM_TYPE_GDDR3;
+		if (pfb474 & 0x00000002)
+			dev_priv->vram_type = NV_MEM_TYPE_DDR2;
+		if (pfb474 & 0x00000001)
+			dev_priv->vram_type = NV_MEM_TYPE_DDR1;
+	} else {
+		dev_priv->vram_type = NV_MEM_TYPE_STOLEN;
+	}
+
+	dev_priv->vram_size = nv_rd32(dev, 0x10020c) & 0xff000000;
+	return 0;
+}
+
 int
 nv40_fb_init(struct drm_device *dev)
 {