Re: [PATCHv2 3/4] drm/komeda: use afbc helpers

From: Ayan Halder <Ayan.Halder@arm.com>
To: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Cc: nd <nd@arm.com>, "kernel@collabora.com" <kernel@collabora.com>,
	David Airlie <airlied@linux.ie>,
	Liviu Dudau <Liviu.Dudau@arm.com>,
	"linux-rockchip@lists.infradead.org"
	<linux-rockchip@lists.infradead.org>,
	"james qian wang (Arm Technology China)"
	<james.qian.wang@arm.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	Mihail Atanassov <Mihail.Atanassov@arm.com>,
	Sean Paul <sean@poorly.run>
Subject: Re: [PATCHv2 3/4] drm/komeda: use afbc helpers
Date: Fri, 8 Nov 2019 16:09:54 +0000	[thread overview]
Message-ID: <20191108160954.GA17321@arm.com> (raw)
In-Reply-To: <20191104221228.3588-4-andrzej.p@collabora.com>

On Mon, Nov 04, 2019 at 11:12:27PM +0100, Andrzej Pietrasiewicz wrote:
> There are afbc helpers available.
> 
> Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> ---
>  .../arm/display/komeda/komeda_format_caps.h   |  1 -
>  .../arm/display/komeda/komeda_framebuffer.c   | 44 +++++++------------
>  2 files changed, 17 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_format_caps.h b/drivers/gpu/drm/arm/display/komeda/komeda_format_caps.h
> index 32273cf18f7c..607eea80e60c 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_format_caps.h
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_format_caps.h
> @@ -33,7 +33,6 @@
>  
>  #define AFBC_TH_LAYOUT_ALIGNMENT	8
>  #define AFBC_HEADER_SIZE		16
> -#define AFBC_SUPERBLK_ALIGNMENT		128
>  #define AFBC_SUPERBLK_PIXELS		256
>  #define AFBC_BODY_START_ALIGNMENT	1024
>  #define AFBC_TH_BODY_START_ALIGNMENT	4096
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> index 1b01a625f40e..e9c87551a5b8 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_framebuffer.c
> @@ -4,6 +4,7 @@
>   * Author: James.Qian.Wang <james.qian.wang@arm.com>
>   *
>   */
> +#include <drm/drm_afbc.h>
>  #include <drm/drm_device.h>
>  #include <drm/drm_fb_cma_helper.h>
>  #include <drm/drm_gem.h>
> @@ -43,8 +44,7 @@ komeda_fb_afbc_size_check(struct komeda_fb *kfb, struct drm_file *file,
>  	struct drm_framebuffer *fb = &kfb->base;
>  	const struct drm_format_info *info = fb->format;
>  	struct drm_gem_object *obj;
> -	u32 alignment_w = 0, alignment_h = 0, alignment_header, n_blocks, bpp;
> -	u64 min_size;
> +	u32 alignment_w = 0, alignment_h = 0, alignment_header, bpp;
>  
>  	obj = drm_gem_object_lookup(file, mode_cmd->handles[0]);
>  	if (!obj) {
> @@ -52,19 +52,15 @@ komeda_fb_afbc_size_check(struct komeda_fb *kfb, struct drm_file *file,
>  		return -ENOENT;
>  	}
>  
> -	switch (fb->modifier & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK) {
> -	case AFBC_FORMAT_MOD_BLOCK_SIZE_32x8:
> -		alignment_w = 32;
> -		alignment_h = 8;
> -		break;
> -	case AFBC_FORMAT_MOD_BLOCK_SIZE_16x16:
> -		alignment_w = 16;
> -		alignment_h = 16;
> -		break;
> -	default:
> -		WARN(1, "Invalid AFBC_FORMAT_MOD_BLOCK_SIZE: %lld.\n",
> -		     fb->modifier & AFBC_FORMAT_MOD_BLOCK_SIZE_MASK);
> -		break;
> +	if (!drm_afbc_get_superblk_wh(fb->modifier, &alignment_w, &alignment_h))
> +		return -EINVAL;
> +
> +	if ((alignment_w != 16 || alignment_h != 16) &&
> +	    (alignment_w != 32 || alignment_h != 8)) {
> +		DRM_DEBUG_KMS("Unsupported afbc tile w/h [%d/%d]\n",
> +			      alignment_w, alignment_h);
> +
> +		return -EINVAL;
To be honest, the previous code looks much more readable
>  	}
>  
>  	/* tiled header afbc */
> @@ -84,20 +80,14 @@ komeda_fb_afbc_size_check(struct komeda_fb *kfb, struct drm_file *file,
>  		goto check_failed;
>  	}
>  
> -	n_blocks = (kfb->aligned_w * kfb->aligned_h) / AFBC_SUPERBLK_PIXELS;
> -	kfb->offset_payload = ALIGN(n_blocks * AFBC_HEADER_SIZE,
> -				    alignment_header);
> -
>  	bpp = komeda_get_afbc_format_bpp(info, fb->modifier);
> -	kfb->afbc_size = kfb->offset_payload + n_blocks *
> -			 ALIGN(bpp * AFBC_SUPERBLK_PIXELS / 8,
> -			       AFBC_SUPERBLK_ALIGNMENT);
> -	min_size = kfb->afbc_size + fb->offsets[0];
> -	if (min_size > obj->size) {
> -		DRM_DEBUG_KMS("afbc size check failed, obj_size: 0x%zx. min_size 0x%llx.\n",
> -			      obj->size, min_size);
We need kfb->offset_payload and kfb->afbc_size to set some registers
in d71_layer_update(). At this moment I feel like punching myself for
making the suggestion to consider abstracting some of the komeda's afbc
checks. To me it does not look like komeda(in the current shape) can take
much advantage of the generic _afbc_fb_check() function (as was suggested
previously by Danvet).

However, I will let james.qian.wang@arm.com,
Mihail.Atanassov@arm.com, Ben.Davis@arm.com comment here to see if
there could be a way of abstracting the afbc bits from komeda.

Thanks anyways for taking a stab at this.
-Ayan
> +
> +	if (!drm_afbc_check_fb_size(mode_cmd->pitches[0], bpp,
> +				    mode_cmd->width, mode_cmd->height,
> +				    alignment_w, alignment_h,
> +				    obj->size, mode_cmd->offsets[0],
> +				    AFBC_SUPERBLK_ALIGNMENT))
>  		goto check_failed;
> -	}
>  
>  	fb->obj[0] = obj;
>  	return 0;
> -- 
> 2.17.1
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