[RFC PATCH 12/97] drm/i915/guc: Don't repeat CTB layout calculations

[Matthew Brost]

On Thu, May 06, 2021 at 12:13:26PM -0700, Matthew Brost wrote:
> From: Michal Wajdeczko <michal.wajdeczko at intel.com>
> 
> We can retrieve offsets to cmds buffers and descriptor from
> actual pointers that we already keep locally.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
> ---
>  drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> index dbece569fbe4..fbd6bd20f588 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
> @@ -244,6 +244,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
>  {
>  	struct intel_guc *guc = ct_to_guc(ct);
>  	u32 base, cmds;
> +	void *blob;
>  	int err;
>  	int i;
>  
> @@ -251,15 +252,18 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
>  
>  	/* vma should be already allocated and map'ed */
>  	GEM_BUG_ON(!ct->vma);
> +	GEM_BUG_ON(!i915_gem_object_has_pinned_pages(ct->vma->obj));

This doesn't really have anything to do with this patch, but again this
patch will be squashed into a large patch updating the GuC firmware, so
I think this is fine.

With that:
Reviewed-by: Matthew Brost <matthew.brost at intel.com>

>  	base = intel_guc_ggtt_offset(guc, ct->vma);
>  
> -	/* (re)initialize descriptors
> -	 * cmds buffers are in the second half of the blob page
> -	 */
> +	/* blob should start with send descriptor */
> +	blob = __px_vaddr(ct->vma->obj);
> +	GEM_BUG_ON(blob != ct->ctbs[CTB_SEND].desc);
> +
> +	/* (re)initialize descriptors */
>  	for (i = 0; i < ARRAY_SIZE(ct->ctbs); i++) {
>  		GEM_BUG_ON((i != CTB_SEND) && (i != CTB_RECV));
>  
> -		cmds = base + PAGE_SIZE / 4 * i + PAGE_SIZE / 2;
> +		cmds = base + ptrdiff(ct->ctbs[i].cmds, blob);
>  		CT_DEBUG(ct, "%d: cmds addr=%#x\n", i, cmds);
>  
>  		guc_ct_buffer_reset(&ct->ctbs[i], cmds);
> @@ -269,12 +273,12 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct)
>  	 * Register both CT buffers starting with RECV buffer.
>  	 * Descriptors are in first half of the blob.
>  	 */
> -	err = ct_register_buffer(ct, base + PAGE_SIZE / 4 * CTB_RECV,
> +	err = ct_register_buffer(ct, base + ptrdiff(ct->ctbs[CTB_RECV].desc, blob),
>  				 INTEL_GUC_CT_BUFFER_TYPE_RECV);
>  	if (unlikely(err))
>  		goto err_out;
>  
> -	err = ct_register_buffer(ct, base + PAGE_SIZE / 4 * CTB_SEND,
> +	err = ct_register_buffer(ct, base + ptrdiff(ct->ctbs[CTB_SEND].desc, blob),
>  				 INTEL_GUC_CT_BUFFER_TYPE_SEND);
>  	if (unlikely(err))
>  		goto err_deregister;
> -- 
> 2.28.0
>