drm/nouveau/bios: fix OF loading

Currently OF bios load fails for a few reasons:
 - checksum failure
 - bios size too small
 - no PCIR header
 - bios length not a multiple of 4

In this change, we resolve all of the above by ignoring any checksum
failures (since OF VBIOS tends not to have a checksum), and faking the
PCIR data when loading from OF.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

3 files changed, 36 insertions, 11 deletions

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/priv.h b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/priv.h
index e0ec2a6b7b79..212800ecdce9 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/priv.h
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/priv.h
@@ -8,7 +8,10 @@ struct nvbios_source {
         void *(*init)(struct nvkm_bios *, const char *);
         void  (*fini)(void *);
         u32   (*read)(void *, u32 offset, u32 length, struct nvkm_bios *);
+        u32   (*size)(void *);
         bool rw;
+        bool ignore_checksum;
+        bool no_pcir;
 };
 
 int nvbios_extend(struct nvkm_bios *, u32 length);
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadow.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadow.c
index 792f017525f6..b2557e87afdd 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadow.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadow.c
@@ -45,7 +45,7 @@ shadow_fetch(struct nvkm_bios *bios, struct shadow *mthd, u32 upto)
                 u32 read = mthd->func->read(data, start, limit - start, bios);
                 bios->size = start + read;
         }
-        return bios->size >= limit;
+        return bios->size >= upto;
 }
 
 static int
@@ -55,14 +55,22 @@ shadow_image(struct nvkm_bios *bios, int idx, u32 offset, struct shadow *mthd)
         struct nvbios_image image;
         int score = 1;
 
-        if (!shadow_fetch(bios, mthd, offset + 0x1000)) {
-                nvkm_debug(subdev, "%08x: header fetch failed\n", offset);
-                return 0;
-        }
+        if (mthd->func->no_pcir) {
+                image.base = 0;
+                image.type = 0;
+                image.size = mthd->func->size(mthd->data);
+                image.last = 1;
+        } else {
+                if (!shadow_fetch(bios, mthd, offset + 0x1000)) {
+                        nvkm_debug(subdev, "%08x: header fetch failed\n",
+                                   offset);
+                        return 0;
+                }
 
-        if (!nvbios_image(bios, idx, &image)) {
-                nvkm_debug(subdev, "image %d invalid\n", idx);
-                return 0;
+                if (!nvbios_image(bios, idx, &image)) {
+                        nvkm_debug(subdev, "image %d invalid\n", idx);
+                        return 0;
+                }
         }
         nvkm_debug(subdev, "%08x: type %02x, %d bytes\n",
                    image.base, image.type, image.size);
@@ -74,7 +82,8 @@ shadow_image(struct nvkm_bios *bios, int idx, u32 offset, struct shadow *mthd)
 
         switch (image.type) {
         case 0x00:
-                if (nvbios_checksum(&bios->data[image.base], image.size)) {
+                if (!mthd->func->ignore_checksum &&
+                    nvbios_checksum(&bios->data[image.base], image.size)) {
                         nvkm_debug(subdev, "%08x: checksum failed\n",
                                    image.base);
                         if (mthd->func->rw)
diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
index bd60d7dd09f5..4bf486b57101 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bios/shadowof.c
@@ -21,6 +21,7 @@
  *
  */
 #include "priv.h"
+
 #include <core/pci.h>
 
 #if defined(__powerpc__)
@@ -33,17 +34,26 @@ static u32
 of_read(void *data, u32 offset, u32 length, struct nvkm_bios *bios)
 {
         struct priv *priv = data;
-        if (offset + length <= priv->size) {
+        if (offset < priv->size) {
+                length = min_t(u32, length, priv->size - offset);
                 memcpy_fromio(bios->data + offset, priv->data + offset, length);
                 return length;
         }
         return 0;
 }
 
+static u32
+of_size(void *data)
+{
+        struct priv *priv = data;
+        return priv->size;
+}
+
 static void *
 of_init(struct nvkm_bios *bios, const char *name)
 {
-        struct pci_dev *pdev = bios->subdev.device->func->pci(bios->subdev.device)->pdev;
+        struct nvkm_device *device = bios->subdev.device;
+        struct pci_dev *pdev = device->func->pci(device)->pdev;
         struct device_node *dn;
         struct priv *priv;
         if (!(dn = pci_device_to_OF_node(pdev)))
@@ -62,7 +72,10 @@ nvbios_of = {
         .init = of_init,
         .fini = (void(*)(void *))kfree,
         .read = of_read,
+        .size = of_size,
         .rw = false,
+        .ignore_checksum = true,
+        .no_pcir = true,
 };
 #else
 const struct nvbios_source