Message-ID: <dc0c448e-f03d-43ea-b571-3e96d859f89b@ideasonboard.com>
Date: Wed, 17 Jan 2024 17:32:57 +0200
From: Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
To: Anatoliy Klymenko <anatoliy.klymenko@....com>,
 laurent.pinchart@...asonboard.com, maarten.lankhorst@...ux.intel.com,
 mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, daniel@...ll.ch,
 michal.simek@....com, dri-devel@...ts.freedesktop.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] drm: xlnx: zynqmp_dpsub: Set live video in format

Hi Anatoliy,

On 13/01/2024 01:42, Anatoliy Klymenko wrote:
> Live video input format is expected to be set as
> "bus-format" property in connected remote endpoint.
> Program live video input format DPSUB registers.
> Set display layer mode in layer creation context.

Some comments inline below. But one thing to improve is the commit desc.

I think this needs more explanation on what's the issue here. So 
basically something like what's the feature in question, why it's not 
working or what's missing, and what does this patch do to get it working.

And while often it's reasonable to expect some level of understanding of 
the HW in question, it doesn't hurt to give some clarifications on the 
names used (here the "live video input").

> Signed-off-by: Anatoliy Klymenko <anatoliy.klymenko@....com>
> ---
>   drivers/gpu/drm/xlnx/zynqmp_disp.c      | 109 ++++++++++++++++++++++--
>   drivers/gpu/drm/xlnx/zynqmp_disp.h      |   3 +-
>   drivers/gpu/drm/xlnx/zynqmp_disp_regs.h |   8 +-
>   drivers/gpu/drm/xlnx/zynqmp_dp.c        |   2 +-
>   drivers/gpu/drm/xlnx/zynqmp_kms.c       |   2 +-
>   5 files changed, 107 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.c b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> index 8a39b3accce5..83af3ad9cdb5 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_disp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_disp.c
> @@ -20,8 +20,10 @@
>   #include <linux/dmaengine.h>
>   #include <linux/module.h>
>   #include <linux/of.h>
> +#include <linux/of_graph.h>
>   #include <linux/platform_device.h>
>   #include <linux/slab.h>
> +#include <linux/media-bus-format.h>

Alphabetical order, please.

>   #include "zynqmp_disp.h"
>   #include "zynqmp_disp_regs.h"
> @@ -67,12 +69,16 @@
>   /**
>    * struct zynqmp_disp_format - Display subsystem format information
>    * @drm_fmt: DRM format (4CC)
> + * @bus_fmt: Live video media bus format
>    * @buf_fmt: AV buffer format
>    * @swap: Flag to swap R & B for RGB formats, and U & V for YUV formats
>    * @sf: Scaling factors for color components
>    */
>   struct zynqmp_disp_format {
> -	u32 drm_fmt;
> +	union {
> +		u32 drm_fmt;
> +		u32 bus_fmt;
> +	};
>   	u32 buf_fmt;
>   	bool swap;
>   	const u32 *sf;
> @@ -354,6 +360,16 @@ static const struct zynqmp_disp_format avbuf_gfx_fmts[] = {
>   	},
>   };
>   
> +/* TODO: add support for different formats */
> +static const struct zynqmp_disp_format avbuf_live_vid_fmts[] = {
> +	{
> +		.bus_fmt	= MEDIA_BUS_FMT_UYVY8_1X16,
> +		.buf_fmt	= ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_BPC_8 |
> +				  ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YUV422,
> +		.sf		= scaling_factors_888,
> +	}
> +};
> +
>   static u32 zynqmp_disp_avbuf_read(struct zynqmp_disp *disp, int reg)
>   {
>   	return readl(disp->avbuf.base + reg);
> @@ -369,6 +385,34 @@ static bool zynqmp_disp_layer_is_video(const struct zynqmp_disp_layer *layer)
>   	return layer->id == ZYNQMP_DPSUB_LAYER_VID;
>   }
>   
> +/**
> + * zynqmp_disp_avbuf_set_live_format - Set live input format for a layer
> + * @disp: Display controller
> + * @layer: The layer
> + * @fmt: The format information
> + *
> + * Set the live video input format for @layer to @fmt.
> + */
> +static void zynqmp_disp_avbuf_set_live_format(struct zynqmp_disp *disp,
> +					      struct zynqmp_disp_layer *layer,
> +					      const struct zynqmp_disp_format *fmt)
> +{
> +	u32 reg, i;
> +
> +	reg = zynqmp_disp_layer_is_video(layer)
> +	    ? ZYNQMP_DISP_AV_BUF_LIVE_VID_CONFIG
> +	    : ZYNQMP_DISP_AV_BUF_LIVE_GFX_CONFIG;
> +	zynqmp_disp_avbuf_write(disp, reg, fmt->buf_fmt);
> +
> +	for (i = 0; i < ZYNQMP_DISP_AV_BUF_NUM_SF; ++i) {
> +		reg = zynqmp_disp_layer_is_video(layer)
> +		    ? ZYNQMP_DISP_AV_BUF_LIVD_VID_COMP_SF(i)
> +		    : ZYNQMP_DISP_AV_BUF_LIVD_GFX_COMP_SF(i);
> +		zynqmp_disp_avbuf_write(disp, reg, fmt->sf[i]);
> +	}
> +	layer->disp_fmt = fmt;
> +}
> +
>   /**
>    * zynqmp_disp_avbuf_set_format - Set the input format for a layer
>    * @disp: Display controller
> @@ -902,15 +946,12 @@ u32 *zynqmp_disp_layer_drm_formats(struct zynqmp_disp_layer *layer,
>   /**
>    * zynqmp_disp_layer_enable - Enable a layer
>    * @layer: The layer
> - * @mode: Operating mode of layer
>    *
>    * Enable the @layer in the audio/video buffer manager and the blender. DMA
>    * channels are started separately by zynqmp_disp_layer_update().
>    */
> -void zynqmp_disp_layer_enable(struct zynqmp_disp_layer *layer,
> -			      enum zynqmp_dpsub_layer_mode mode)
> +void zynqmp_disp_layer_enable(struct zynqmp_disp_layer *layer)
>   {
> -	layer->mode = mode;
>   	zynqmp_disp_avbuf_enable_video(layer->disp, layer);
>   	zynqmp_disp_blend_layer_enable(layer->disp, layer);
>   }
> @@ -950,11 +991,12 @@ void zynqmp_disp_layer_set_format(struct zynqmp_disp_layer *layer,
>   	layer->disp_fmt = zynqmp_disp_layer_find_format(layer, info->format);
>   	layer->drm_fmt = info;
>   
> -	zynqmp_disp_avbuf_set_format(layer->disp, layer, layer->disp_fmt);
> -
> -	if (!layer->disp->dpsub->dma_enabled)
> +	/* Live format set during layer creation */
> +	if (layer->mode == ZYNQMP_DPSUB_LAYER_LIVE)
>   		return;
>   
> +	zynqmp_disp_avbuf_set_format(layer->disp, layer, layer->disp_fmt);
> +
>   	/*
>   	 * Set pconfig for each DMA channel to indicate they're part of a
>   	 * video group.
> @@ -1083,7 +1125,7 @@ static int zynqmp_disp_layer_request_dma(struct zynqmp_disp *disp,
>   	unsigned int i;
>   	int ret;
>   
> -	if (!disp->dpsub->dma_enabled)
> +	if (layer->mode == ZYNQMP_DPSUB_LAYER_LIVE)
>   		return 0;
>   
>   	for (i = 0; i < layer->info->num_channels; i++) {
> @@ -1104,6 +1146,43 @@ static int zynqmp_disp_layer_request_dma(struct zynqmp_disp *disp,
>   	return 0;
>   }
>   
> +/**
> + * zynqmp_disp_get_live_fmt - Get live video format
> + * @disp: Display controller
> + * @layer: Display layer
> + *
> + * Parse connected remote endpoint and retrieve configured bus-format
> + *
> + * Return: live format pointer on success, NULL otherwise
> + */
> +static const struct zynqmp_disp_format *zynqmp_disp_get_live_fmt(struct zynqmp_disp *disp,
> +								 struct zynqmp_disp_layer *layer)
> +{
> +	struct device_node *local, *remote, *dpsub = disp->dev->of_node;
> +	int rc, i;
> +	u32 fmt;
> +
> +	local = of_graph_get_endpoint_by_regs(dpsub, layer->id, -1);
> +	if (!local)
> +		return NULL;
> +
> +	remote = of_graph_get_remote_endpoint(local);

The "remote" here is some PL component that provides the live stream? 
I'm not sure if there's a rule for these, but I think usually a driver 
should only read its own properties. I would add 'bus-format' to dp 
endpoint's DT data.

> +	of_node_put(local);
> +	if (!remote)
> +		return NULL;
> +
> +	rc = of_property_read_u32_index(remote, "bus-format", 0, &fmt);

Does this require a change to the DT bindings?

Why is this not of_property_read_u32()?

> +	of_node_put(remote);
> +	if (rc)
> +		return NULL;
> +
> +	for (i = 0; i < ARRAY_SIZE(avbuf_live_vid_fmts); ++i)
> +		if (avbuf_live_vid_fmts[i].bus_fmt == fmt)
> +			return &avbuf_live_vid_fmts[i];
> +
> +	return NULL;
> +}
> +
>   /**
>    * zynqmp_disp_create_layers - Create and initialize all layers
>    * @disp: Display controller
> @@ -1130,9 +1209,15 @@ static int zynqmp_disp_create_layers(struct zynqmp_disp *disp)
>   
>   	for (i = 0; i < ARRAY_SIZE(disp->layers); i++) {
>   		struct zynqmp_disp_layer *layer = &disp->layers[i];
> +		const struct zynqmp_disp_format *disp_fmt;
>   
>   		layer->id = i;
>   		layer->disp = disp;
> +		/* For now we assume dpsub works in either live or non-live mode for both layers.
> +		 * Hybrid mode is not supported yet.
> +		 */
> +		layer->mode = disp->dpsub->dma_enabled ? ZYNQMP_DPSUB_LAYER_NONLIVE
> +						       : ZYNQMP_DPSUB_LAYER_LIVE;
>   		layer->info = &layer_info[i];
>   
>   		ret = zynqmp_disp_layer_request_dma(disp, layer);
> @@ -1140,6 +1225,12 @@ static int zynqmp_disp_create_layers(struct zynqmp_disp *disp)
>   			goto err;
>   
>   		disp->dpsub->layers[i] = layer;
> +
> +		if (layer->mode == ZYNQMP_DPSUB_LAYER_LIVE) {
> +			disp_fmt = zynqmp_disp_get_live_fmt(disp, layer);
> +			if (disp_fmt)
> +				zynqmp_disp_avbuf_set_live_format(disp, layer, disp_fmt);
> +		}
>   	}
>   
>   	return 0;
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp.h b/drivers/gpu/drm/xlnx/zynqmp_disp.h
> index 123cffac08be..f3357b2d5c09 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_disp.h
> +++ b/drivers/gpu/drm/xlnx/zynqmp_disp.h
> @@ -62,8 +62,7 @@ void zynqmp_disp_blend_set_global_alpha(struct zynqmp_disp *disp,
>   
>   u32 *zynqmp_disp_layer_drm_formats(struct zynqmp_disp_layer *layer,
>   				   unsigned int *num_formats);
> -void zynqmp_disp_layer_enable(struct zynqmp_disp_layer *layer,
> -			      enum zynqmp_dpsub_layer_mode mode);
> +void zynqmp_disp_layer_enable(struct zynqmp_disp_layer *layer);
>   void zynqmp_disp_layer_disable(struct zynqmp_disp_layer *layer);
>   void zynqmp_disp_layer_set_format(struct zynqmp_disp_layer *layer,
>   				  const struct drm_format_info *info);
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_disp_regs.h b/drivers/gpu/drm/xlnx/zynqmp_disp_regs.h
> index f92a006d5070..926e07c255bb 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_disp_regs.h
> +++ b/drivers/gpu/drm/xlnx/zynqmp_disp_regs.h
> @@ -165,10 +165,10 @@
>   #define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_BPC_10		0x2
>   #define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_BPC_12		0x3
>   #define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_BPC_MASK		GENMASK(2, 0)
> -#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_RGB		0x0
> -#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YUV444	0x1
> -#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YUV422	0x2
> -#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YONLY	0x3
> +#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_RGB		0x00
> +#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YUV444	0x10
> +#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YUV422	0x20
> +#define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_YONLY	0x30

What's this about? Were these wrong before? Sounds like a separate patch 
needed for these.

>   #define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_FMT_MASK		GENMASK(5, 4)
>   #define ZYNQMP_DISP_AV_BUF_LIVE_CONFIG_CB_FIRST		BIT(8)
>   #define ZYNQMP_DISP_AV_BUF_PALETTE_MEMORY		0x400
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> index 571c5dbc97e5..59616ed1c3d9 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
> @@ -1295,7 +1295,7 @@ static void zynqmp_dp_disp_enable(struct zynqmp_dp *dp,
>   	/* TODO: Make the format configurable. */
>   	info = drm_format_info(DRM_FORMAT_YUV422);
>   	zynqmp_disp_layer_set_format(layer, info);
> -	zynqmp_disp_layer_enable(layer, ZYNQMP_DPSUB_LAYER_LIVE);
> +	zynqmp_disp_layer_enable(layer);
>   
>   	if (layer_id == ZYNQMP_DPSUB_LAYER_GFX)
>   		zynqmp_disp_blend_set_global_alpha(dp->dpsub->disp, true, 255);
> diff --git a/drivers/gpu/drm/xlnx/zynqmp_kms.c b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> index db3bb4afbfc4..43bf416b33d5 100644
> --- a/drivers/gpu/drm/xlnx/zynqmp_kms.c
> +++ b/drivers/gpu/drm/xlnx/zynqmp_kms.c
> @@ -122,7 +122,7 @@ static void zynqmp_dpsub_plane_atomic_update(struct drm_plane *plane,
>   
>   	/* Enable or re-enable the plane if the format has changed. */
>   	if (format_changed)
> -		zynqmp_disp_layer_enable(layer, ZYNQMP_DPSUB_LAYER_NONLIVE);
> +		zynqmp_disp_layer_enable(layer);
>   }
>   
>   static const struct drm_plane_helper_funcs zynqmp_dpsub_plane_helper_funcs = {

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