Subject: Re: [PATCH v1 6/6] drm/mediatek: apply CMDQ control flow

From: CK Hu <[email-masked]>
Date: Tue, 3 Dec 2019 09:38:34 +0800

Hi, Bibby:

On Thu, 2019-11-28 at 10:42 +0800, Bibby Hsieh wrote:
> Unlike other SoCs, MT8183 does not have "shadow"
> registers for performaing an atomic video mode
> set or page flip at vblank/vsync.
> 
> The CMDQ (Commend Queue) in MT8183 is used to help
> update all relevant display controller registers
> with critical time limation.
> 
> Signed-off-by: YT Shen <[email-masked]>
> Signed-off-by: CK Hu <[email-masked]>
> Signed-off-by: Philipp Zabel <[email-masked]>
> Signed-off-by: Bibby Hsieh <[email-masked]>
> Signed-off-by: Yongqiang Niu <[email-masked]>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c     | 86 ++++++++++++++++++++-
>  drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c | 31 ++++++++
>  2 files changed, 113 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index fcf4e755e0bd..1b4e537ac3c1 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -12,6 +12,8 @@
>  #include <drm/drm_plane_helper.h>
>  #include <drm/drm_probe_helper.h>
>  #include <drm/drm_vblank.h>
> +#include <linux/of_address.h>
> +#include <linux/soc/mediatek/mtk-cmdq.h>
>  
>  #include "mtk_drm_drv.h"
>  #include "mtk_drm_crtc.h"
> @@ -42,6 +44,9 @@ struct mtk_drm_crtc {
>  	unsigned int			layer_nr;
>  	bool				pending_planes;
>  
> +	struct cmdq_client		*cmdq_client;
> +	u32				cmdq_event;
> +
>  	void __iomem			*config_regs;
>  	const struct mtk_mmsys_reg_data *mmsys_reg_data;
>  	struct mtk_disp_mutex		*mutex;
> @@ -56,6 +61,11 @@ struct mtk_crtc_state {
>  	unsigned int			pending_width;
>  	unsigned int			pending_height;
>  	unsigned int			pending_vrefresh;
> +	struct cmdq_pkt			*cmdq_handle;
> +};
> +
> +struct mtk_cmdq_cb_data {
> +	struct cmdq_pkt			*cmdq_handle;
>  };
>  
>  static inline struct mtk_drm_crtc *to_mtk_crtc(struct drm_crtc *c)
> @@ -229,6 +239,46 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
>  	return NULL;
>  }
>  
> +#ifdef CONFIG_MTK_CMDQ
> +static void ddp_cmdq_cb(struct cmdq_cb_data data)
> +{
> +	struct mtk_cmdq_cb_data *cb_data = data.data;
> +
> +	cmdq_pkt_destroy(cb_data->cmdq_handle);
> +	kfree(cb_data);
> +}
> +
> +static void mtk_cmdq_acquire(struct drm_crtc *crtc)
> +{
> +	struct mtk_crtc_state *mtk_crtc_state =
> +			to_mtk_crtc_state(crtc->state);
> +	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
> +
> +	mtk_crtc_state->cmdq_handle =
> +			cmdq_pkt_create(mtk_crtc->cmdq_client,
> +					PAGE_SIZE);

I would like to remove atomic feature in cmdq driver and drm driver
could reuse the pkt. Please refer to [1] for detail.

[1]
http://lists.infradead.org/pipermail/linux-mediatek/2019-January/016866.html

> +	cmdq_pkt_clear_event(mtk_crtc_state->cmdq_handle,
> +			     mtk_crtc->cmdq_event);
> +	cmdq_pkt_wfe(mtk_crtc_state->cmdq_handle, mtk_crtc->cmdq_event);
> +}
> +
> +static void mtk_cmdq_release(struct drm_crtc *crtc)
> +{
> +	struct mtk_crtc_state *mtk_crtc_state =
> +			to_mtk_crtc_state(crtc->state);
> +	struct mtk_cmdq_cb_data *cb_data;
> +
> +	cb_data = kmalloc(sizeof(*cb_data), GFP_KERNEL);
> +	if (!cb_data) {
> +		DRM_DEV_ERROR(crtc->dev->dev, "Failed to alloc cb_data\n");
> +		return;
> +	}
> +
> +	cb_data->cmdq_handle = mtk_crtc_state->cmdq_handle;
> +	cmdq_pkt_flush_async(mtk_crtc_state->cmdq_handle,
> +			     ddp_cmdq_cb, cb_data);
> +}
> +#endif
>  static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc)
>  {
>  	struct drm_crtc *crtc = &mtk_crtc->base;
> @@ -383,7 +433,8 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
>  	if (state->pending_config) {
>  		mtk_ddp_comp_config(comp, state->pending_width,
>  				    state->pending_height,
> -				    state->pending_vrefresh, 0, NULL);
> +				    state->pending_vrefresh, 0,
> +				    state->cmdq_handle);
>  
>  		state->pending_config = false;
>  	}
> @@ -403,7 +454,8 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
>  
>  			if (comp)
>  				mtk_ddp_comp_layer_config(comp, local_layer,
> -							  plane_state, NULL);
> +							  plane_state,
> +							  state->cmdq_handle);
>  			plane_state->pending.config = false;
>  		}
>  		mtk_crtc->pending_planes = false;
> @@ -454,6 +506,13 @@ void mtk_drm_crtc_cursor_update(struct drm_crtc *crtc, struct drm_plane *plane,
>  		mtk_crtc_ddp_config(crtc);
>  		mtk_disp_mutex_release(mtk_crtc->mutex);
>  	}
> +#ifdef CONFIG_MTK_CMDQ
> +	if (mtk_crtc->cmdq_client) {
> +		mtk_cmdq_acquire(crtc);
> +		mtk_crtc_ddp_config(crtc);
> +		mtk_cmdq_release(crtc);
> +	}
> +#endif
>  	mutex_unlock(&priv->hw_lock);
>  }
>  
> @@ -570,6 +629,13 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
>  		mtk_crtc_ddp_config(crtc);
>  		mtk_disp_mutex_release(mtk_crtc->mutex);
>  	}
> +#ifdef CONFIG_MTK_CMDQ
> +	if (mtk_crtc->cmdq_client) {
> +		mtk_cmdq_acquire(crtc);
> +		mtk_crtc_ddp_config(crtc);
> +		mtk_cmdq_release(crtc);
> +	}
> +#endif

This part is almost the same as the one in mtk_drm_crtc_cursor_update(),
try to merge them.

>  }
>  
>  static const struct drm_crtc_funcs mtk_crtc_funcs = {
> @@ -619,7 +685,7 @@ void mtk_crtc_ddp_irq(struct drm_crtc *crtc, struct mtk_ddp_comp *comp)
>  	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
>  	struct mtk_drm_private *priv = crtc->dev->dev_private;
>  
> -	if (!priv->data->shadow_register)
> +	if (!priv->data->shadow_register && !mtk_crtc->cmdq_client)
>  		mtk_crtc_ddp_config(crtc);
>  
>  	mtk_drm_finish_page_flip(mtk_crtc);
> @@ -761,6 +827,18 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
>  	drm_mode_crtc_set_gamma_size(&mtk_crtc->base, MTK_LUT_SIZE);
>  	drm_crtc_enable_color_mgmt(&mtk_crtc->base, 0, false, MTK_LUT_SIZE);
>  	priv->num_pipes++;
> -
> +#ifdef CONFIG_MTK_CMDQ
> +	mtk_crtc->cmdq_client =
> +			cmdq_mbox_create(dev, drm_crtc_index(&mtk_crtc->base),
> +					 2000);
> +	of_property_read_u32_index(dev->of_node, "mediatek,gce-events",
> +				   drm_crtc_index(&mtk_crtc->base),
> +				   &mtk_crtc->cmdq_event);
> +	if (IS_ERR(mtk_crtc->cmdq_client)) {
> +		dev_dbg(dev, "mtk_crtc %d failed to create mailbox client, writing register by CPU now\n",
> +			drm_crtc_index(&mtk_crtc->base));
> +		mtk_crtc->cmdq_client = NULL;
> +	}
> +#endif
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> index 6d0f349ddf82..9cc12af2bc06 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
> @@ -370,6 +370,9 @@ int mtk_ddp_comp_init(struct device *dev, struct device_node *node,
>  		      const struct mtk_ddp_comp_funcs *funcs)
>  {
>  	struct platform_device *comp_pdev;
> +	struct resource res;
> +	struct cmdq_client_reg *cmdq_reg;
> +	int ret = 0;
>  
>  	if (comp_id < 0 || comp_id >= DDP_COMPONENT_ID_MAX)
>  		return -EINVAL;
> @@ -404,6 +407,34 @@ int mtk_ddp_comp_init(struct device *dev, struct device_node *node,
>  	}
>  	comp->dev = &comp_pdev->dev;
>  
> +#ifdef CONFIG_MTK_CMDQ
> +	if (of_address_to_resource(node, 0, &res) != 0) {
> +		dev_err(dev, "Missing reg in %s node\n",
> +			node->full_name);
> +		return -EINVAL;
> +	}
> +	comp->regs_pa = res.start;
> +
> +	comp_pdev = of_find_device_by_node(node);
> +	if (!comp_pdev) {
> +		dev_warn(dev, "Waiting for component device %s\n",
> +			 node->full_name);
> +		return -EPROBE_DEFER;
> +	}
> +
> +	cmdq_reg = kzalloc(sizeof(*cmdq_reg), GFP_KERNEL);
> +	if (!cmdq_reg)
> +		return -EINVAL;
> +
> +	ret = cmdq_dev_get_client_reg(&comp_pdev->dev, cmdq_reg, 0);
> +	if (ret != 0)
> +		dev_dbg(&comp_pdev->dev,
> +			"get mediatek,gce-client-reg fail!\n");
> +	else
> +		comp->subsys = cmdq_reg->subsys;
> +
> +	kfree(cmdq_reg);
> +#endif

I would like to move this part to the patch "drm/mediatek: support CMDQ
interface in ddp component".

Regards,
CK

>  	return 0;
>  }

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