Re: [PATCH 1/3] drm/msm: support firmware-name for zap fw

Bjorn Andersson
2020-01-08T19:04:54Z

On Wed 08 Jan 10:48 PST 2020, Jordan Crouse wrote:

> On Tue, Jan 07, 2020 at 05:38:42PM -0800, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > Since zap firmware can be device specific, allow for a firmware-name
> > property in the zap node to specify which firmware to load, similarly to
> > the scheme used for dsp/wifi/etc.
> >
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> > drivers/gpu/drm/msm/adreno/adreno_gpu.c | 32 ++++++++++++++++++++++---
> > 1 file changed, 29 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > index 112e8b8a261e..aa8737bd58db 100644
> > --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> > @@ -26,6 +26,7 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname,
> > {
> > struct device *dev = &gpu->pdev->dev;
> > const struct firmware *fw;
> > + const char *signed_fwname = NULL;
> > struct device_node *np, *mem_np;
> > struct resource r;
> > phys_addr_t mem_phys;
> > @@ -58,8 +59,33 @@ static int zap_shader_load_mdt(struct msm_gpu *gpu, const char *fwname,
> >
> > mem_phys = r.start;
> >
> > - /* Request the MDT file for the firmware */
> > - fw = adreno_request_fw(to_adreno_gpu(gpu), fwname);
> > + /*
> > + * Check for a firmware-name property. This is the new scheme
> > + * to handle firmware that may be signed with device specific
> > + * keys, allowing us to have a different zap fw path for different
> > + * devices.
> > + *
> > + * If the firmware-name property is found, we bypass the
> > + * adreno_request_fw() mechanism, because we don't need to handle
> > + * the /lib/firmware/qcom/* vs /lib/firmware/* case.
> > + *
> > + * If the firmware-name property is not found, for backwards
> > + * compatibility we fall back to the fwname from the gpulist
> > + * table.
> > + */
> > + of_property_read_string_index(np, "firmware-name", 0, &signed_fwname);
> > + if (signed_fwname) {
> > + fwname = signed_fwname;
> > + ret = request_firmware_direct(&fw, signed_fwname, gpu->dev->dev);
> > + if (ret) {
> > + DRM_DEV_ERROR(dev, "could not load signed zap firmware: %d\n", ret);
> > + fw = ERR_PTR(ret);
> > + }
> > + } else {
> > + /* Request the MDT file for the firmware */
> > + fw = adreno_request_fw(to_adreno_gpu(gpu), fwname);
> > + }
> > +
>
> Since DT seems to be the trend for target specific firmware names I think we
> should plan to quickly deprecate the legacy name and not require new targets to
> set it. If a zap node is going to be opt in then it isn't onerous to ask
> the developer to set the additional property for each target platform.
>

For the zap specifically I agree that it would be nice to require this
property, but for non-zap firmware it seems reasonable to continue with
the existing scheme.

Regards,
Bjorn