[Nouveau] [PATCH] gr: fallback to legacy paths during firmware lookup

[Ilia Mirkin]

On Wed, Nov 2, 2016 at 12:54 AM, Alexandre Courbot <acourbot at nvidia.com> wrote:
> Look for firmware files using the legacy ("nouveau/nvxx_fucxxxx") path
> if they cannot be found in the new, "official" path. User setups were
> broken by the switch, which is bad.
>
> There are only 4 firmware files we may want to look up that way, so
> hardcode them into the lookup function. All new firmware files should
> use the standard "nvidia/<chip>/gr/" path.
>
> Fixes: 8539b37acef7 ("drm/nouveau/gr: use NVIDIA-provided external firmwares")
> Signed-off-by: Alexandre Courbot <acourbot at nvidia.com>
> ---
>  drm/nouveau/nvkm/engine/gr/gf100.c | 56 ++++++++++++++++++++++++++++++++++----
>  1 file changed, 51 insertions(+), 5 deletions(-)
>
> diff --git a/drm/nouveau/nvkm/engine/gr/gf100.c b/drm/nouveau/nvkm/engine/gr/gf100.c
> index 157919c788e6..9e65adbab21c 100644
> --- a/drm/nouveau/nvkm/engine/gr/gf100.c
> +++ b/drm/nouveau/nvkm/engine/gr/gf100.c
> @@ -1756,24 +1756,70 @@ gf100_gr_ = {
>  };
>
>  int
> +gf100_gr_ctor_fw_legacy(struct gf100_gr *gr, const char *fwname,
> +                       struct gf100_gr_fuc *fuc)
> +{
> +       struct nvkm_subdev *subdev = &gr->base.engine.subdev;
> +       struct nvkm_device *device = subdev->device;
> +       const struct firmware *fw;
> +       char f[32];
> +       int ret;
> +
> +       snprintf(f, sizeof(f), "nouveau/nv%02x_%s", device->chipset, fwname);
> +       ret = request_firmware(&fw, f, device->dev);
> +       if (ret) {
> +               snprintf(f, sizeof(f), "nouveau/%s", fwname);
> +               ret = request_firmware(&fw, f, device->dev);
> +               if (ret) {
> +                       nvkm_error(subdev, "failed to load %s\n", fwname);
> +                       return ret;
> +               }
> +       }
> +
> +       fuc->size = fw->size;
> +       fuc->data = kmemdup(fw->data, fuc->size, GFP_KERNEL);
> +       release_firmware(fw);
> +       return (fuc->data != NULL) ? 0 : -ENOMEM;
> +}
> +
> +int
>  gf100_gr_ctor_fw(struct gf100_gr *gr, const char *fwname,
>                  struct gf100_gr_fuc *fuc)
>  {
>         struct nvkm_subdev *subdev = &gr->base.engine.subdev;
>         struct nvkm_device *device = subdev->device;
> +       const char *legacy_fwname = NULL;
>         const struct firmware *fw;
>         int ret;
>
>         ret = nvkm_firmware_get(device, fwname, &fw);
> -       if (ret) {
> +       /* firmware found, success! */
> +       if (!ret) {
> +               fuc->size = fw->size;
> +               fuc->data = kmemdup(fw->data, fuc->size, GFP_KERNEL);
> +               nvkm_firmware_put(fw);
> +               return (fuc->data != NULL) ? 0 : -ENOMEM;
> +       }
> +
> +       /* see if this firmware has a legacy path */
> +       if (!strcmp(fwname, "fecs_inst"))
> +               legacy_fwname = "fuc409c";
> +       else if (!strcmp(fwname, "fecs_data"))
> +               legacy_fwname = "fuc409d";
> +       else if (!strcmp(fwname, "gpccs_inst"))
> +               legacy_fwname = "fuc41ac";
> +       else if (!strcmp(fwname, "gpccs_data"))
> +               legacy_fwname = "fuc41ad";

As I mentioned on IRC, I find this strcmp thing a little jarring. It
should be pretty easy to just pass the legacy fwname into
gf100_gr_ctor_fw directly - there are only a handful of callers, and
most would just pass NULL in as the legacy fwname - only the ones in
gf100.c would pass the "old" names in.

Otherwise this looks great, thanks for taking care of it!

> +
> +       /* nope, let's just return the error we got */
> +       if (!legacy_fwname) {
>                 nvkm_error(subdev, "failed to load %s\n", fwname);
>                 return ret;
>         }
>
> -       fuc->size = fw->size;
> -       fuc->data = kmemdup(fw->data, fuc->size, GFP_KERNEL);
> -       nvkm_firmware_put(fw);
> -       return (fuc->data != NULL) ? 0 : -ENOMEM;
> +       /* yes, try to load from the legacy path */
> +       nvkm_debug(subdev, "%s: falling back to legacy path\n", fwname);
> +       return gf100_gr_ctor_fw_legacy(gr, legacy_fwname, fuc);
>  }
>
>  int
> --
> 2.10.0
>
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