[Intel-gfx] [PATCH v2 8/8] drm/i915/uc: Unify uC firmware upload

[Chris Wilson]

Quoting Daniele Ceraolo Spurio (2019-07-24 03:21:53)
> +static int uc_fw_xfer(struct intel_uc_fw *uc_fw, struct intel_gt *gt,
> +                     u32 wopcm_offset, u32 dma_flags)
> +{
> +       struct intel_uncore *uncore = gt->uncore;
> +       u64 offset;
> +       int ret;
> +
> +       intel_uncore_forcewake_get(uncore, FORCEWAKE_ALL);
> +
> +       /* Set the source address for the uCode */
> +       offset = uc_fw_ggtt_offset(uc_fw, gt->ggtt) + uc_fw->header_offset;
> +       GEM_BUG_ON(upper_32_bits(offset) & 0xFFFF0000);
> +       intel_uncore_write_fw(uncore, DMA_ADDR_0_LOW, lower_32_bits(offset));
> +       intel_uncore_write_fw(uncore, DMA_ADDR_0_HIGH, upper_32_bits(offset));
> +
> +       /* Set the DMA destination */
> +       intel_uncore_write_fw(uncore, DMA_ADDR_1_LOW, wopcm_offset);
> +       intel_uncore_write_fw(uncore, DMA_ADDR_1_HIGH, DMA_ADDRESS_SPACE_WOPCM);
> +
> +       /*
> +        * Set the transfer size. The header plus uCode will be copied to WOPCM
> +        * via DMA, excluding any other components
> +        */
> +       intel_uncore_write_fw(uncore, DMA_COPY_SIZE,
> +                             uc_fw->header_size + uc_fw->ucode_size);
> +
> +       /* Start the DMA */
> +       intel_uncore_write_fw(uncore, DMA_CTRL,
> +                             _MASKED_BIT_ENABLE(dma_flags | START_DMA));
> +
> +       /* Wait for DMA to finish */
> +       ret = intel_wait_for_register_fw(uncore, DMA_CTRL, START_DMA, 0, 100);
> +       if (ret)
> +               DRM_ERROR("DMA for %s fw failed, err=%d\n",
> +                         intel_uc_fw_type_repr(uc_fw->type), ret);

Note the errno will never be that interesting here, it's a wait. I would
suggest including DMA_CTL as that looks like it contains status bits as
well as control.

And let's note use DRM_ERROR() if we can help it, and use dev_err() when
applicable. (Might be time for a new crusade.)

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris