[Intel-gfx] [PATCH] drm/i915/guc: Move firmware size check out of generic code

[Sagar Arun Kamble]

On 10/6/2017 2:31 PM, Michal Wajdeczko wrote:
> Checking GuC firmware size can be done in GuC specific code
> right before DMA copy as it is unlikely to fail anyway.
>
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> ---
>   drivers/gpu/drm/i915/intel_guc_loader.c | 14 +++++++++++---
>   drivers/gpu/drm/i915/intel_uc_fw.c      |  8 --------
>   2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
> index c7a800a..f245aa5 100644
> --- a/drivers/gpu/drm/i915/intel_guc_loader.c
> +++ b/drivers/gpu/drm/i915/intel_guc_loader.c
> @@ -198,6 +198,7 @@ static int guc_ucode_xfer_dma(struct drm_i915_private *dev_priv,
>   	unsigned long offset;
>   	struct sg_table *sg = vma->pages;
>   	u32 status, rsa[UOS_RSA_SCRATCH_MAX_COUNT];
> +	u32 size = guc_fw->header_size + guc_fw->ucode_size;
>   	int i, ret = 0;
>   
>   	/* where RSA signature starts */
> @@ -208,9 +209,16 @@ static int guc_ucode_xfer_dma(struct drm_i915_private *dev_priv,
>   	for (i = 0; i < UOS_RSA_SCRATCH_MAX_COUNT; i++)
>   		I915_WRITE(UOS_RSA_SCRATCH(i), rsa[i]);
>   
> -	/* The header plus uCode will be copied to WOPCM via DMA, excluding any
> -	 * other components */
> -	I915_WRITE(DMA_COPY_SIZE, guc_fw->header_size + guc_fw->ucode_size);
> +	/*
> +	 * The header plus uCode will be copied to WOPCM via DMA, excluding any
> +	 * other components. Make sure that firmware fits there.
> +	 */
> +	if (unlikely(size > intel_guc_wopcm_size(dev_priv))) {
> +		DRM_ERROR("GuC: Firmware is too large (%dB) to fit in WOPCM\n",
> +			  size);
> +		return -EFBIG;
Top level function is converting this to -EAGAIN and would be 
unnecessary to retry in that case.
> +	}
> +	I915_WRITE(DMA_COPY_SIZE, size);
>   
>   	/* Set the source address for the new blob */
>   	offset = guc_ggtt_offset(vma) + guc_fw->header_offset;
> diff --git a/drivers/gpu/drm/i915/intel_uc_fw.c b/drivers/gpu/drm/i915/intel_uc_fw.c
> index 766b1cb..482115b 100644
> --- a/drivers/gpu/drm/i915/intel_uc_fw.c
> +++ b/drivers/gpu/drm/i915/intel_uc_fw.c
> @@ -108,14 +108,6 @@ void intel_uc_fw_fetch(struct drm_i915_private *dev_priv,
>   	 */
>   	switch (uc_fw->type) {
>   	case INTEL_UC_FW_TYPE_GUC:
> -		/* Header and uCode will be loaded to WOPCM. Size of the two. */
> -		size = uc_fw->header_size + uc_fw->ucode_size;
> -
> -		/* Top 32k of WOPCM is reserved (8K stack + 24k RC6 context). */
This comment was not correct. So removal makes sense.
> -		if (size > intel_guc_wopcm_size(dev_priv)) {
> -			DRM_ERROR("Firmware is too large to fit in WOPCM\n");
> -			goto fail;
> -		}
>   		uc_fw->major_ver_found = css->guc.sw_version >> 16;
>   		uc_fw->minor_ver_found = css->guc.sw_version & 0xFFFF;
>   		break;