drm/nouveau: Calculate reserved VRAM for PRAMIN value before use.

'drm/nouveau: rework vram init/fini ordering a little' changed
the order of instmem.init() and nouveau_mem_vram_init() which
resulted in using ramin_rsvd_vram before it was calculated and
failing to init any accel on pre-NV50 cards.

Since it's only used on <NV50 just calculate it where it's needed
and leave it as default 0 for NV50.

Signed-off-by: Younes Manton <younes.m@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
diff --git a/drivers/gpu/drm/nouveau/nv04_instmem.c b/drivers/gpu/drm/nouveau/nv04_instmem.c
index ae36bfc..e2075de 100644
--- a/drivers/gpu/drm/nouveau/nv04_instmem.c
+++ b/drivers/gpu/drm/nouveau/nv04_instmem.c
@@ -28,6 +28,31 @@
 	/* RAMIN always available */
 	dev_priv->ramin_available = true;
 
+	/* Reserve space at end of VRAM for PRAMIN */
+	if (dev_priv->card_type >= NV_40) {
+		u32 vs = hweight8((nv_rd32(dev, 0x001540) & 0x0000ff00) >> 8);
+		u32 rsvd;
+
+		/* estimate grctx size, the magics come from nv40_grctx.c */
+		if      (dev_priv->chipset == 0x40) rsvd = 0x6aa0 * vs;
+		else if (dev_priv->chipset  < 0x43) rsvd = 0x4f00 * vs;
+		else if (nv44_graph_class(dev))	    rsvd = 0x4980 * vs;
+		else				    rsvd = 0x4a40 * vs;
+		rsvd += 16 * 1024;
+		rsvd *= dev_priv->engine.fifo.channels;
+
+		/* pciegart table */
+		if (drm_pci_device_is_pcie(dev))
+			rsvd += 512 * 1024;
+
+		/* object storage */
+		rsvd += 512 * 1024;
+
+		dev_priv->ramin_rsvd_vram = round_up(rsvd, 4096);
+	} else {
+		dev_priv->ramin_rsvd_vram = 512 * 1024;
+	}
+
 	/* Setup shared RAMHT */
 	ret = nouveau_gpuobj_new_fake(dev, 0x10000, ~0, 4096,
 				      NVOBJ_FLAG_ZERO_ALLOC, &ramht);