Re: [PATCH v8 06/14] drm/bridge: imx: Add i.MX8qm/qxp display pixel link support

Laurent Pinchart
2022-06-09T09:31:26Z

Hi Liu,

Thank you for the patch.

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 ?

> + 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.

> + if (pl->id < 0) {
> + DRM_DEV_ERROR(dev,
> + "failed to get pixel link node alias id: %d\n",
> + pl->id);
> + return pl->id;
> + }
> +
> + pl->dev = dev;
> +
> + pl->dc_id = pl->id / 2;
> + pl->stream_id = pl->id % 2;
> +
> + pl->sink_rsc = pl->dc_id ? IMX_SC_R_DC_1 : IMX_SC_R_DC_0;
> +
> + if (pl->stream_id == 0) {
> + pl->mst_addr_ctrl = IMX_SC_C_PXL_LINK_MST1_ADDR;
> + pl->mst_en_ctrl = IMX_SC_C_PXL_LINK_MST1_ENB;
> + pl->mst_vld_ctrl = IMX_SC_C_PXL_LINK_MST1_VLD;
> + pl->sync_ctrl = IMX_SC_C_SYNC_CTRL0;
> + } else {
> + pl->mst_addr_ctrl = IMX_SC_C_PXL_LINK_MST2_ADDR;
> + pl->mst_en_ctrl = IMX_SC_C_PXL_LINK_MST2_ENB;
> + pl->mst_vld_ctrl = IMX_SC_C_PXL_LINK_MST2_VLD;
> + pl->sync_ctrl = IMX_SC_C_SYNC_CTRL1;
> + }
> +
> + /* disable all controls to POR default */
> + ret = imx8qxp_pixel_link_disable_all_controls(pl);
> + if (ret)
> + return ret;
> +
> + pl->next_bridge = imx8qxp_pixel_link_find_next_bridge(pl);
> + if (IS_ERR(pl->next_bridge)) {
> + ret = PTR_ERR(pl->next_bridge);
> + if (ret != -EPROBE_DEFER)
> + DRM_DEV_ERROR(dev, "failed to find next bridge: %d\n",
> + ret);
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, pl);
> +
> + pl->bridge.driver_private = pl;
> + pl->bridge.funcs = &imx8qxp_pixel_link_bridge_funcs;
> + pl->bridge.of_node = np;
> +
> + drm_bridge_add(&pl->bridge);
> +
> + return ret;
> +}
> +
> +static int imx8qxp_pixel_link_bridge_remove(struct platform_device *pdev)
> +{
> + struct imx8qxp_pixel_link *pl = platform_get_drvdata(pdev);
> +
> + drm_bridge_remove(&pl->bridge);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id imx8qxp_pixel_link_dt_ids[] = {
> + { .compatible = "fsl,imx8qm-dc-pixel-link", },
> + { .compatible = "fsl,imx8qxp-dc-pixel-link", },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, imx8qxp_pixel_link_dt_ids);
> +
> +static struct platform_driver imx8qxp_pixel_link_bridge_driver = {
> + .probe = imx8qxp_pixel_link_bridge_probe,
> + .remove = imx8qxp_pixel_link_bridge_remove,
> + .driver = {
> + .of_match_table = imx8qxp_pixel_link_dt_ids,
> + .name = DRIVER_NAME,
> + },
> +};
> +module_platform_driver(imx8qxp_pixel_link_bridge_driver);
> +
> +MODULE_DESCRIPTION("i.MX8QXP/QM display pixel link bridge driver");
> +MODULE_AUTHOR("Liu Ying <victor.liu@nxp.com>");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:" DRIVER_NAME);

--
Regards,

Laurent Pinchart