drm/nvc0/ltcg: read LTS count at startup

Not really sure how to confirm this 100%, but, the numbers match on all the
traces I have for NVCx (2 LTS), NVD9 (1LTS) and NVEx (4LTS).

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

diff --git a/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c b/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
index 7c2840c..078a2b9 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/ltcg/nvc0.c
@@ -26,6 +26,7 @@
 
 struct nvc0_ltcg_priv {
        struct nouveau_ltcg base;
+       u32 subp_nr;
 };
 
 static void
@@ -49,7 +50,7 @@ nvc0_ltcg_intr(struct nouveau_subdev *subdev)
        units = nv_rd32(priv, 0x00017c);
        while (units) {
                u32 subp, unit = ffs(units) - 1;
-               for (subp = 0; subp < 2; subp++)
+               for (subp = 0; subp < priv->subp_nr; subp++)
                        nvc0_ltcg_subp_isr(priv, unit, subp);
                units &= ~(1 << unit);
        }
@@ -73,6 +74,7 @@ nvc0_ltcg_ctor(struct nouveau_object *parent, struct nouveau_object *engine,
        if (ret)
                return ret;
 
+       priv->subp_nr = nv_rd32(priv, 0x17e8dc) >> 24;
        nv_mask(priv, 0x17e820, 0x00100000, 0x00000000); /* INTR_EN &= ~0x10 */
 
        nv_subdev(priv)->intr = nvc0_ltcg_intr;