Re: [PATCH v4 3/8] drm/mediatek: add shadow register support

[CK Hu <ck.hu@mediatek.com>]

Hi, YT:

One comment inline.


On Fri, 2016-07-15 at 18:07 +0800, YT Shen wrote:
> We need to acquire mutex before using the resources,
> and need to release it after finished.
> So we don't need to write registers in the blanking period.
> 
> Signed-off-by: YT Shen <yt.shen@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c |   75 +++++++++++++++++++------------
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.c  |   22 +++++++++
>  drivers/gpu/drm/mediatek/mtk_drm_ddp.h  |    2 +
>  drivers/gpu/drm/mediatek/mtk_drm_drv.h  |    1 +
>  4 files changed, 71 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index 24aa3ba..80d9641 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -315,6 +315,42 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
>  	pm_runtime_put(drm->dev);
>  }
>  
> +static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
> +{
> +	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> +	struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
> +	struct mtk_ddp_comp *ovl = mtk_crtc->ddp_comp[0];
> +	unsigned int i;
> +
> +	/*
> +	 * TODO: instead of updating the registers here, we should prepare
> +	 * working registers in atomic_commit and let the hardware command
> +	 * queue update module registers on vblank.
> +	 */
> +	if (state->pending_config) {
> +		mtk_ddp_comp_config(ovl, state->pending_width,
> +				    state->pending_height,
> +				    state->pending_vrefresh);
> +
> +		state->pending_config = false;
> +	}
> +
> +	if (mtk_crtc->pending_planes) {
> +		for (i = 0; i < OVL_LAYER_NR; i++) {
> +			struct drm_plane *plane = &mtk_crtc->planes[i].base;
> +			struct mtk_plane_state *plane_state;
> +
> +			plane_state = to_mtk_plane_state(plane->state);
> +
> +			if (plane_state->pending.config) {
> +				mtk_ddp_comp_layer_config(ovl, i, plane_state);
> +				plane_state->pending.config = false;
> +			}
> +		}
> +		mtk_crtc->pending_planes = false;
> +	}
> +}
> +
>  static void mtk_drm_crtc_enable(struct drm_crtc *crtc)
>  {
>  	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> @@ -391,6 +427,7 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
>  				      struct drm_crtc_state *old_crtc_state)
>  {
>  	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> +	struct mtk_drm_private *priv = crtc->dev->dev_private;
>  	unsigned int pending_planes = 0;
>  	int i;
>  
> @@ -409,6 +446,12 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
>  	}
>  	if (pending_planes)
>  		mtk_crtc->pending_planes = true;
> +
> +	if (priv->data->shadow_register) {
> +		mtk_disp_mutex_acquire(mtk_crtc->mutex);
> +		mtk_crtc_ddp_config(crtc);
> +		mtk_disp_mutex_release(mtk_crtc->mutex);
> +	}
>  }
>  
>  static const struct drm_crtc_funcs mtk_crtc_funcs = {
> @@ -453,36 +496,10 @@ err_cleanup_crtc:
>  void mtk_crtc_ddp_irq(struct drm_crtc *crtc, struct mtk_ddp_comp *ovl)
>  {
>  	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> -	struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
> -	unsigned int i;
> +	struct mtk_drm_private *priv = crtc->dev->dev_private;
>  
> -	/*
> -	 * TODO: instead of updating the registers here, we should prepare
> -	 * working registers in atomic_commit and let the hardware command
> -	 * queue update module registers on vblank.
> -	 */
> -	if (state->pending_config) {
> -		mtk_ddp_comp_config(ovl, state->pending_width,
> -				    state->pending_height,
> -				    state->pending_vrefresh);
> -
> -		state->pending_config = false;
> -	}
> -
> -	if (mtk_crtc->pending_planes) {
> -		for (i = 0; i < OVL_LAYER_NR; i++) {
> -			struct drm_plane *plane = &mtk_crtc->planes[i].base;
> -			struct mtk_plane_state *plane_state;
> -
> -			plane_state = to_mtk_plane_state(plane->state);
> -
> -			if (plane_state->pending.config) {
> -				mtk_ddp_comp_layer_config(ovl, i, plane_state);
> -				plane_state->pending.config = false;
> -			}
> -		}
> -		mtk_crtc->pending_planes = false;
> -	}
> +	if (!priv->data->shadow_register)
> +		mtk_crtc_ddp_config(crtc);
>  
>  	mtk_drm_finish_page_flip(mtk_crtc);
>  }
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> index 8030769..fa53806 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.c
> @@ -12,6 +12,7 @@
>   */
>  
>  #include <linux/clk.h>
> +#include <linux/iopoll.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
>  #include <linux/platform_device.h>
> @@ -32,6 +33,7 @@
>  #define DISP_REG_CONFIG_MMSYS_CG_CON0		0x100
>  
>  #define DISP_REG_MUTEX_EN(n)	(0x20 + 0x20 * (n))
> +#define DISP_REG_MUTEX(n)	(0x24 + 0x20 * (n))
>  #define DISP_REG_MUTEX_RST(n)	(0x28 + 0x20 * (n))
>  #define DISP_REG_MUTEX_MOD(n)	(0x2c + 0x20 * (n))
>  #define DISP_REG_MUTEX_SOF(n)	(0x30 + 0x20 * (n))
> @@ -300,6 +302,26 @@ void mtk_disp_mutex_disable(struct mtk_disp_mutex *mutex)
>  	writel(0, ddp->regs + DISP_REG_MUTEX_EN(mutex->id));
>  }
>  
> +void mtk_disp_mutex_acquire(struct mtk_disp_mutex *mutex)
> +{
> +	struct mtk_ddp *ddp = container_of(mutex, struct mtk_ddp,
> +					   mutex[mutex->id]);
> +	u32 tmp;
> +
> +	writel(1, ddp->regs + DISP_REG_MUTEX_EN(mutex->id));
> +	writel(1, ddp->regs + DISP_REG_MUTEX(mutex->id));
> +	readl_poll_timeout_atomic(ddp->regs + DISP_REG_MUTEX(mutex->id), tmp,
> +				  tmp & 0x2, 1, 10000);

Nothing to do with timeout? I think it should print error message here
or reset HW to recover it.

> +}
> +
> +void mtk_disp_mutex_release(struct mtk_disp_mutex *mutex)
> +{
> +	struct mtk_ddp *ddp = container_of(mutex, struct mtk_ddp,
> +					   mutex[mutex->id]);
> +
> +	writel(0, ddp->regs + DISP_REG_MUTEX(mutex->id));
> +}
> +
>  static int mtk_ddp_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp.h b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
> index 92c1175..f9a7991 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp.h
> @@ -37,5 +37,7 @@ void mtk_disp_mutex_remove_comp(struct mtk_disp_mutex *mutex,
>  				enum mtk_ddp_comp_id id);
>  void mtk_disp_mutex_unprepare(struct mtk_disp_mutex *mutex);
>  void mtk_disp_mutex_put(struct mtk_disp_mutex *mutex);
> +void mtk_disp_mutex_acquire(struct mtk_disp_mutex *mutex);
> +void mtk_disp_mutex_release(struct mtk_disp_mutex *mutex);
>  
>  #endif /* MTK_DRM_DDP_H */
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> index fa0b106..94f8b66 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
> @@ -33,6 +33,7 @@ struct mtk_mmsys_driver_data {
>  	unsigned int main_len;
>  	const enum mtk_ddp_comp_id *ext_path;
>  	unsigned int ext_len;
> +	bool shadow_register;
>  };
>  
>  struct mtk_drm_private {