Re: [PATCH 2/8] drm/ingenic: Simplify code by using hwdescs array

[Thomas Zimmermann]

Hi

Am 08.08.21 um 15:45 schrieb Paul Cercueil:
> Instead of having one 'hwdesc' variable for the plane #0 and one for the
> plane #1, use a 'hwdesc[2]' array, where the DMA hardware descriptors
> are indexed by the plane's number.
>
> Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> ---
>   drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 38 ++++++++++++-----------
>   1 file changed, 20 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> index e42eb43d8020..bc71ba44ccf4 100644
> --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
> @@ -49,8 +49,7 @@ struct ingenic_dma_hwdesc {
>   } __aligned(16);
>   
>   struct ingenic_dma_hwdescs {
> -	struct ingenic_dma_hwdesc hwdesc_f0;
> -	struct ingenic_dma_hwdesc hwdesc_f1;
> +	struct ingenic_dma_hwdesc hwdesc[2];
>   	struct ingenic_dma_hwdesc hwdesc_pal;
>   	u16 palette[256] __aligned(16);
>   };
> @@ -141,6 +140,13 @@ static inline struct ingenic_drm *drm_nb_get_priv(struct notifier_block *nb)
>   	return container_of(nb, struct ingenic_drm, clock_nb);
>   }
>   
> +static inline dma_addr_t dma_hwdesc_addr(const struct ingenic_drm *priv, bool use_f1)

Using the plane index instead of a boolean would be more aligned to the 
way this function is being used.

> +{
> +	u32 offset = offsetof(struct ingenic_dma_hwdescs, hwdesc[use_f1]);

use_f1 is a function parameter. Is offsetof guaranteed to be evaluated 
at runtime?

> +
> +	return priv->dma_hwdescs_phys + offset;
> +}
> +
>   static int ingenic_drm_update_pixclk(struct notifier_block *nb,
>   				     unsigned long action,
>   				     void *data)
> @@ -562,6 +568,7 @@ static void ingenic_drm_plane_atomic_update(struct drm_plane *plane,
>   	struct ingenic_dma_hwdesc *hwdesc;
>   	unsigned int width, height, cpp, offset;
>   	dma_addr_t addr;
> +	bool use_f1;
>   	u32 fourcc;
>   
>   	if (newstate && newstate->fb) {
> @@ -569,16 +576,14 @@ static void ingenic_drm_plane_atomic_update(struct drm_plane *plane,
>   			drm_fb_cma_sync_non_coherent(&priv->drm, oldstate, newstate);
>   
>   		crtc_state = newstate->crtc->state;
> +		use_f1 = priv->soc_info->has_osd && plane != &priv->f0;
>   
>   		addr = drm_fb_cma_get_gem_addr(newstate->fb, newstate, 0);
>   		width = newstate->src_w >> 16;
>   		height = newstate->src_h >> 16;
>   		cpp = newstate->fb->format->cpp[0];
>   
> -		if (!priv->soc_info->has_osd || plane == &priv->f0)
> -			hwdesc = &priv->dma_hwdescs->hwdesc_f0;
> -		else
> -			hwdesc = &priv->dma_hwdescs->hwdesc_f1;
> +		hwdesc = &priv->dma_hwdescs->hwdesc[use_f1];

Maybe add a helper that looks up the hwdesc field for a given plane?

>   
>   		hwdesc->addr = addr;
>   		hwdesc->cmd = JZ_LCD_CMD_EOF_IRQ | (width * height * cpp / 4);
> @@ -591,9 +596,9 @@ static void ingenic_drm_plane_atomic_update(struct drm_plane *plane,
>   			if (fourcc == DRM_FORMAT_C8)
>   				offset = offsetof(struct ingenic_dma_hwdescs, hwdesc_pal);
>   			else
> -				offset = offsetof(struct ingenic_dma_hwdescs, hwdesc_f0);
> +				offset = offsetof(struct ingenic_dma_hwdescs, hwdesc[0]);
>   
> -			priv->dma_hwdescs->hwdesc_f0.next = priv->dma_hwdescs_phys + offset;
> +			priv->dma_hwdescs->hwdesc[0].next = priv->dma_hwdescs_phys + offset;

Maybe priv->dma_hwdescs_phys + offset could be computed in a more 
flexible helper than dma_hwdesc_addr().

>   
>   			crtc_state->color_mgmt_changed = fourcc == DRM_FORMAT_C8;
>   		}
> @@ -964,20 +969,17 @@ static int ingenic_drm_bind(struct device *dev, bool has_components)
>   
>   
>   	/* Configure DMA hwdesc for foreground0 plane */
> -	dma_hwdesc_phys_f0 = priv->dma_hwdescs_phys
> -		+ offsetof(struct ingenic_dma_hwdescs, hwdesc_f0);
> -	priv->dma_hwdescs->hwdesc_f0.next = dma_hwdesc_phys_f0;
> -	priv->dma_hwdescs->hwdesc_f0.id = 0xf0;
> +	dma_hwdesc_phys_f0 = dma_hwdesc_addr(priv, 0);
> +	priv->dma_hwdescs->hwdesc[0].next = dma_hwdesc_phys_f0;
> +	priv->dma_hwdescs->hwdesc[0].id = 0xf0;
>   
>   	/* Configure DMA hwdesc for foreground1 plane */
> -	dma_hwdesc_phys_f1 = priv->dma_hwdescs_phys
> -		+ offsetof(struct ingenic_dma_hwdescs, hwdesc_f1);
> -	priv->dma_hwdescs->hwdesc_f1.next = dma_hwdesc_phys_f1;
> -	priv->dma_hwdescs->hwdesc_f1.id = 0xf1;
> +	dma_hwdesc_phys_f1 = dma_hwdesc_addr(priv, 1);
> +	priv->dma_hwdescs->hwdesc[1].next = dma_hwdesc_phys_f1;
> +	priv->dma_hwdescs->hwdesc[1].id = 0xf1;
>   
>   	/* Configure DMA hwdesc for palette */
> -	priv->dma_hwdescs->hwdesc_pal.next = priv->dma_hwdescs_phys
> -		+ offsetof(struct ingenic_dma_hwdescs, hwdesc_f0);
> +	priv->dma_hwdescs->hwdesc_pal.next = dma_hwdesc_phys_f0;
>   	priv->dma_hwdescs->hwdesc_pal.id = 0xc0;
>   	priv->dma_hwdescs->hwdesc_pal.addr = priv->dma_hwdescs_phys
>   		+ offsetof(struct ingenic_dma_hwdescs, palette);

Could the setup in these three blocks be moved into a common helper?

Best regards
Thomas


--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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