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Message-ID: <0309ccad2b37c185a83d17e1a8fa3811ac98a49f.camel@nxp.com>
Subject: Re: [PATCH v8 06/14] drm/bridge: imx: Add i.MX8qm/qxp display pixel
 link support
From:   Liu Ying <victor.liu@nxp.com>
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org, andrzej.hajda@intel.com,
        narmstrong@baylibre.com, robert.foss@linaro.org, jonas@kwiboo.se,
        jernej.skrabec@gmail.com, airlied@linux.ie, daniel@ffwll.ch,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
        festevam@gmail.com, linux-imx@nxp.com, lee.jones@linaro.org,
        mchehab@kernel.org, marcel.ziswiler@toradex.com
Date:   Fri, 10 Jun 2022 10:09:19 +0800
In-Reply-To: <YqG9uaGOOp8gEYZh@pendragon.ideasonboard.com>
References: <20220609064931.3068601-1-victor.liu@nxp.com>
         <20220609064931.3068601-7-victor.liu@nxp.com>
         <YqG9uaGOOp8gEYZh@pendragon.ideasonboard.com>
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Hi Laurent,

On Thu, 2022-06-09 at 12:30 +0300, Laurent Pinchart wrote:
> Hi Liu,
> 
> Thank you for the patch.

Thank you for the review.

> 
> On Thu, Jun 09, 2022 at 02:49:23PM +0800, Liu Ying wrote:
> > This patch adds a drm bridge driver for i.MX8qm/qxp display pixel
> > link.
> > The pixel link forms a standard asynchronous linkage between
> > pixel sources(display controller or camera module) and pixel
> > consumers(imaging or displays).  It consists of two distinct
> > functions, a pixel transfer function and a control interface.
> > 
> > Reviewed-by: Robert Foss <robert.foss@linaro.org>
> > Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com> # Colibri
> > iMX8X, LT170410-2WHC, LP156WF1
> > Signed-off-by: Liu Ying <victor.liu@nxp.com>
> > ---
> > Robert, I keep your R-b tag from v5. Let me know if you want me to
> > drop it, as
> > v7 contains a fix for checkpatch complaints.
> > Marcel, as the fix is trivial, I add your T-b tag. Let me know if
> > you want me
> > to drop it.
> > 
> > v7->v8:
> > * No change.
> > 
> > v6->v7:
> > * Fix 'Alignment should match open parenthesis' complaints from
> >   'checkpatch.pl --strict'.
> > * Add Marcel's T-b tag.
> > 
> > v5->v6:
> > * No change.
> > 
> > v4->v5:
> > * Make a comment occupy a line. (Robert)
> > * Add Robert's R-b tag.
> > 
> > v3->v4:
> > * No change.
> > 
> > v2->v3:
> > * Drop two macros which help define functions and define them
> > directly.
> > * Properly disable all pixel link controls to POR value by calling
> >   imx8qxp_pixel_link_disable_all_controls() from
> >   imx8qxp_pixel_link_bridge_probe().
> > 
> > v1->v2:
> > * Rewrite the function to find the next bridge by properly using OF
> > APIs
> >   and dropping unnecessary DT validation. (Rob)
> > 
> >  drivers/gpu/drm/bridge/imx/Kconfig            |   8 +
> >  drivers/gpu/drm/bridge/imx/Makefile           |   1 +
> >  .../gpu/drm/bridge/imx/imx8qxp-pixel-link.c   | 429
> > ++++++++++++++++++
> >  3 files changed, 438 insertions(+)
> >  create mode 100644 drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
> > 
> > diff --git a/drivers/gpu/drm/bridge/imx/Kconfig
> > b/drivers/gpu/drm/bridge/imx/Kconfig
> > index f1c91b6814a5..4d1f027d07f8 100644
> > --- a/drivers/gpu/drm/bridge/imx/Kconfig
> > +++ b/drivers/gpu/drm/bridge/imx/Kconfig
> > @@ -6,3 +6,11 @@ config DRM_IMX8QXP_PIXEL_COMBINER
> >  	help
> >  	  Choose this to enable pixel combiner found in
> >  	  Freescale i.MX8qm/qxp processors.
> > +
> > +config DRM_IMX8QXP_PIXEL_LINK
> > +	tristate "Freescale i.MX8QM/QXP display pixel link"
> > +	depends on OF
> > +	select DRM_KMS_HELPER
> 
> Should this depend on (or select) IMX_SCU ?

Will add 'depends on IMX_SCU'.

> 
> > +	help
> > +	  Choose this to enable display pixel link found in
> > +	  Freescale i.MX8qm/qxp processors.
> > diff --git a/drivers/gpu/drm/bridge/imx/Makefile
> > b/drivers/gpu/drm/bridge/imx/Makefile
> > index 7d7c8d674bf0..c15469fb5789 100644
> > --- a/drivers/gpu/drm/bridge/imx/Makefile
> > +++ b/drivers/gpu/drm/bridge/imx/Makefile
> > @@ -1 +1,2 @@
> >  obj-$(CONFIG_DRM_IMX8QXP_PIXEL_COMBINER) += imx8qxp-pixel-
> > combiner.o
> > +obj-$(CONFIG_DRM_IMX8QXP_PIXEL_LINK) += imx8qxp-pixel-link.o
> > diff --git a/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
> > b/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
> > new file mode 100644
> > index 000000000000..52b9b96549e1
> > --- /dev/null
> > +++ b/drivers/gpu/drm/bridge/imx/imx8qxp-pixel-link.c
> > @@ -0,0 +1,429 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +
> > +/*
> > + * Copyright 2020 NXP
> > + */
> > +
> > +#include <linux/firmware/imx/svc/misc.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include <drm/drm_atomic_state_helper.h>
> > +#include <drm/drm_bridge.h>
> > +#include <drm/drm_print.h>
> > +
> > +#include <dt-bindings/firmware/imx/rsrc.h>
> > +
> > +#define DRIVER_NAME		"imx8qxp-display-pixel-link"
> > +#define PL_MAX_MST_ADDR		3
> > +#define PL_MAX_NEXT_BRIDGES	2
> > +
> > +struct imx8qxp_pixel_link {
> > +	struct drm_bridge bridge;
> > +	struct drm_bridge *next_bridge;
> > +	struct device *dev;
> > +	struct imx_sc_ipc *ipc_handle;
> > +	int id;
> > +	int stream_id;
> > +	int dc_id;
> > +	u32 sink_rsc;
> > +	u32 mst_addr;
> > +	u8 mst_addr_ctrl;
> > +	u8 mst_en_ctrl;
> > +	u8 mst_vld_ctrl;
> > +	u8 sync_ctrl;
> > +};
> > +
> > +static void imx8qxp_pixel_link_enable_mst_en(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->mst_en_ctrl, true);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to enable DC%d stream%d pixel
> > link mst_en: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +}
> > +
> > +static void imx8qxp_pixel_link_enable_mst_vld(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->mst_vld_ctrl, true);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to enable DC%d stream%d pixel
> > link mst_vld: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +}
> > +
> > +static void imx8qxp_pixel_link_enable_sync(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->sync_ctrl, true);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to enable DC%d stream%d pixel
> > link sync: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +}
> > +
> > +static int imx8qxp_pixel_link_disable_mst_en(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->mst_en_ctrl, false);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to disable DC%d stream%d pixel
> > link mst_en: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int imx8qxp_pixel_link_disable_mst_vld(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->mst_vld_ctrl, false);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to disable DC%d stream%d pixel
> > link mst_vld: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static int imx8qxp_pixel_link_disable_sync(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle, pl->sink_rsc,
> > +				      pl->sync_ctrl, false);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to disable DC%d stream%d pixel
> > link sync: %d\n",
> > +			      pl->dc_id, pl->stream_id, ret);
> > +
> > +	return ret;
> > +}
> > +
> > +static void imx8qxp_pixel_link_set_mst_addr(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx_sc_misc_set_control(pl->ipc_handle,
> > +				      pl->sink_rsc, pl->mst_addr_ctrl,
> > +				      pl->mst_addr);
> > +	if (ret)
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "failed to set DC%d stream%d pixel link
> > mst addr(%u): %d\n",
> > +			      pl->dc_id, pl->stream_id, pl->mst_addr,
> > ret);
> > +}
> > +
> > +static int imx8qxp_pixel_link_bridge_attach(struct drm_bridge
> > *bridge,
> > +					    enum
> > drm_bridge_attach_flags flags)
> > +{
> > +	struct imx8qxp_pixel_link *pl = bridge->driver_private;
> > +
> > +	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)) {
> > +		DRM_DEV_ERROR(pl->dev,
> > +			      "do not support creating a
> > drm_connector\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!bridge->encoder) {
> > +		DRM_DEV_ERROR(pl->dev, "missing encoder\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	return drm_bridge_attach(bridge->encoder,
> > +				 pl->next_bridge, bridge,
> > +				 DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> > +}
> > +
> > +static void
> > +imx8qxp_pixel_link_bridge_mode_set(struct drm_bridge *bridge,
> > +				   const struct drm_display_mode *mode,
> > +				   const struct drm_display_mode
> > *adjusted_mode)
> > +{
> > +	struct imx8qxp_pixel_link *pl = bridge->driver_private;
> > +
> > +	imx8qxp_pixel_link_set_mst_addr(pl);
> > +}
> > +
> > +static void
> > +imx8qxp_pixel_link_bridge_atomic_enable(struct drm_bridge *bridge,
> > +					struct drm_bridge_state
> > *old_bridge_state)
> > +{
> > +	struct imx8qxp_pixel_link *pl = bridge->driver_private;
> > +
> > +	imx8qxp_pixel_link_enable_mst_en(pl);
> > +	imx8qxp_pixel_link_enable_mst_vld(pl);
> > +	imx8qxp_pixel_link_enable_sync(pl);
> > +}
> > +
> > +static void
> > +imx8qxp_pixel_link_bridge_atomic_disable(struct drm_bridge
> > *bridge,
> > +					 struct drm_bridge_state
> > *old_bridge_state)
> > +{
> > +	struct imx8qxp_pixel_link *pl = bridge->driver_private;
> > +
> > +	imx8qxp_pixel_link_disable_mst_en(pl);
> > +	imx8qxp_pixel_link_disable_mst_vld(pl);
> > +	imx8qxp_pixel_link_disable_sync(pl);
> > +}
> > +
> > +static const u32 imx8qxp_pixel_link_bus_output_fmts[] = {
> > +	MEDIA_BUS_FMT_RGB888_1X36_CPADLO,
> > +	MEDIA_BUS_FMT_RGB666_1X36_CPADLO,
> > +};
> > +
> > +static bool imx8qxp_pixel_link_bus_output_fmt_supported(u32 fmt)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(imx8qxp_pixel_link_bus_output_fmts);
> > i++) {
> > +		if (imx8qxp_pixel_link_bus_output_fmts[i] == fmt)
> > +			return true;
> > +	}
> > +
> > +	return false;
> > +}
> > +
> > +static u32 *
> > +imx8qxp_pixel_link_bridge_atomic_get_input_bus_fmts(struct
> > drm_bridge *bridge,
> > +						    struct
> > drm_bridge_state *bridge_state,
> > +						    struct
> > drm_crtc_state *crtc_state,
> > +						    struct
> > drm_connector_state *conn_state,
> > +						    u32 output_fmt,
> > +						    unsigned int
> > *num_input_fmts)
> > +{
> > +	u32 *input_fmts;
> > +
> > +	if (!imx8qxp_pixel_link_bus_output_fmt_supported(output_fmt))
> > +		return NULL;
> > +
> > +	*num_input_fmts = 1;
> > +
> > +	input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
> > +	if (!input_fmts)
> > +		return NULL;
> > +
> > +	input_fmts[0] = output_fmt;
> > +
> > +	return input_fmts;
> > +}
> > +
> > +static u32 *
> > +imx8qxp_pixel_link_bridge_atomic_get_output_bus_fmts(struct
> > drm_bridge *bridge,
> > +						     struct
> > drm_bridge_state *bridge_state,
> > +						     struct
> > drm_crtc_state *crtc_state,
> > +						     struct
> > drm_connector_state *conn_state,
> > +						     unsigned int
> > *num_output_fmts)
> > +{
> > +	*num_output_fmts =
> > ARRAY_SIZE(imx8qxp_pixel_link_bus_output_fmts);
> > +	return kmemdup(imx8qxp_pixel_link_bus_output_fmts,
> > +			sizeof(imx8qxp_pixel_link_bus_output_fmts),
> > GFP_KERNEL);
> > +}
> > +
> > +static const struct drm_bridge_funcs
> > imx8qxp_pixel_link_bridge_funcs = {
> > +	.atomic_duplicate_state	=
> > drm_atomic_helper_bridge_duplicate_state,
> > +	.atomic_destroy_state	=
> > drm_atomic_helper_bridge_destroy_state,
> > +	.atomic_reset		= drm_atomic_helper_bridge_reset,
> > +	.attach			= imx8qxp_pixel_link_bridge_attach,
> > +	.mode_set		= imx8qxp_pixel_link_bridge_mode_set,
> > +	.atomic_enable		=
> > imx8qxp_pixel_link_bridge_atomic_enable,
> > +	.atomic_disable		=
> > imx8qxp_pixel_link_bridge_atomic_disable,
> > +	.atomic_get_input_bus_fmts =
> > +			imx8qxp_pixel_link_bridge_atomic_get_input_bus_
> > fmts,
> > +	.atomic_get_output_bus_fmts =
> > +			imx8qxp_pixel_link_bridge_atomic_get_output_bus
> > _fmts,
> > +};
> > +
> > +static int imx8qxp_pixel_link_disable_all_controls(struct
> > imx8qxp_pixel_link *pl)
> > +{
> > +	int ret;
> > +
> > +	ret = imx8qxp_pixel_link_disable_mst_en(pl);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = imx8qxp_pixel_link_disable_mst_vld(pl);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return imx8qxp_pixel_link_disable_sync(pl);
> > +}
> > +
> > +static struct drm_bridge *
> > +imx8qxp_pixel_link_find_next_bridge(struct imx8qxp_pixel_link *pl)
> > +{
> > +	struct device_node *np = pl->dev->of_node;
> > +	struct device_node *port, *remote;
> > +	struct drm_bridge *next_bridge[PL_MAX_NEXT_BRIDGES];
> > +	u32 port_id;
> > +	bool found_port = false;
> > +	int reg, ep_cnt = 0;
> > +	/* select the first next bridge by default */
> > +	int bridge_sel = 0;
> > +
> > +	for (port_id = 1; port_id <= PL_MAX_MST_ADDR + 1; port_id++) {
> > +		port = of_graph_get_port_by_id(np, port_id);
> > +		if (!port)
> > +			continue;
> > +
> > +		if (of_device_is_available(port)) {
> > +			found_port = true;
> > +			of_node_put(port);
> > +			break;
> > +		}
> > +
> > +		of_node_put(port);
> > +	}
> > +
> > +	if (!found_port) {
> > +		DRM_DEV_ERROR(pl->dev, "no available output port\n");
> > +		return ERR_PTR(-ENODEV);
> > +	}
> > +
> > +	for (reg = 0; reg < PL_MAX_NEXT_BRIDGES; reg++) {
> > +		remote = of_graph_get_remote_node(np, port_id, reg);
> > +		if (!remote)
> > +			continue;
> > +
> > +		if (!of_device_is_available(remote->parent)) {
> > +			DRM_DEV_DEBUG(pl->dev,
> > +				      "port%u endpoint%u remote parent
> > is not available\n",
> > +				      port_id, reg);
> > +			of_node_put(remote);
> > +			continue;
> > +		}
> > +
> > +		next_bridge[ep_cnt] = of_drm_find_bridge(remote);
> > +		if (!next_bridge[ep_cnt]) {
> > +			of_node_put(remote);
> > +			return ERR_PTR(-EPROBE_DEFER);
> > +		}
> > +
> > +		/* specially select the next bridge with companion
> > PXL2DPI */
> > +		if (of_find_property(remote, "fsl,companion-pxl2dpi",
> > NULL))
> > +			bridge_sel = ep_cnt;
> > +
> > +		ep_cnt++;
> > +
> > +		of_node_put(remote);
> > +	}
> > +
> > +	pl->mst_addr = port_id - 1;
> > +
> > +	return next_bridge[bridge_sel];
> > +}
> > +
> > +static int imx8qxp_pixel_link_bridge_probe(struct platform_device
> > *pdev)
> > +{
> > +	struct imx8qxp_pixel_link *pl;
> > +	struct device *dev = &pdev->dev;
> > +	struct device_node *np = dev->of_node;
> > +	int ret;
> > +
> > +	pl = devm_kzalloc(dev, sizeof(*pl), GFP_KERNEL);
> > +	if (!pl)
> > +		return -ENOMEM;
> > +
> > +	ret = imx_scu_get_handle(&pl->ipc_handle);
> > +	if (ret) {
> > +		if (ret != -EPROBE_DEFER)
> > +			DRM_DEV_ERROR(dev, "failed to get SCU ipc
> > handle: %d\n",
> > +				      ret);
> > +		return ret;
> > +	}
> > +
> > +	pl->id = of_alias_get_id(np, "dc_pl");
> 
> Could we avoid relying on aliases ? I'd add an id property to the DT
> node instead, or possibly even better a dc id and a stream id.

Will add two properties for dc id and stream id.
Do 'fsl,dc-id' and 'fsl,dc-stream-id' look ok?

Regards,
Liu Ying