Hi Venkateshwar,
On Thu, May 12, 2022 at 07:23:13PM +0530, Venkateshwar Rao Gannavarapu wrote:
> The Xilinx MIPI DSI Tx Subsystem soft IP is used to display video
> data from AXI-4 stream interface.
>
> It supports upto 4 lanes, optional register interface for the DPHY
> and multiple RGB color formats.
> This is a MIPI-DSI host driver and provides DSI bus for panels.
> This driver also helps to communicate with its panel using panel
> framework.
Thanks for submitting this driver. I have added a few comments in the
following that I hope you will find useful to improve the driver.
Sam
>
> Signed-off-by: Venkateshwar Rao Gannavarapu <venkateshwar.rao.gannavarapu@xxxxxxxxxx>
> ---
> drivers/gpu/drm/xlnx/Kconfig | 14 ++
> drivers/gpu/drm/xlnx/Makefile | 1 +
> drivers/gpu/drm/xlnx/xlnx_dsi.c | 456 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 471 insertions(+)
> create mode 100644 drivers/gpu/drm/xlnx/xlnx_dsi.c
>
> diff --git a/drivers/gpu/drm/xlnx/Kconfig b/drivers/gpu/drm/xlnx/Kconfig
> index c3d0826..caa632b 100644
> --- a/drivers/gpu/drm/xlnx/Kconfig
> +++ b/drivers/gpu/drm/xlnx/Kconfig
> @@ -14,3 +14,17 @@ config DRM_ZYNQMP_DPSUB
> This is a DRM/KMS driver for ZynqMP DisplayPort controller. Choose
> this option if you have a Xilinx ZynqMP SoC with DisplayPort
> subsystem.
It would be nice to have it in some sort of alphabetic order, both in
the Kconfig file and also the Makefile.
> +
> +config DRM_XLNX_DSI
> + tristate "Xilinx DRM DSI Subsystem Driver"
> + depends on DRM && OF
> + select DRM_KMS_HELPER
> + select DRM_MIPI_DSI
> + select DRM_PANEL
> + select BACKLIGHT_LCD_SUPPORT
The BACKLIGHT_LCD_SUPPORT symbol is not relevant and can be dropped.
> + select BACKLIGHT_CLASS_DEVICE
> + select DRM_PANEL_SIMPLE
The symbol DRM_PANEL_SIMPLE is used to enable the panel_simple driver
and should not be selected here.
> + help
> + DRM bridge driver for Xilinx programmable DSI subsystem controller.
> + choose this option if you hava a Xilinx MIPI-DSI Tx subsytem in
> + video pipeline.
> diff --git a/drivers/gpu/drm/xlnx/Makefile b/drivers/gpu/drm/xlnx/Makefile
> index 51c24b7..1e97fbe 100644
> --- a/drivers/gpu/drm/xlnx/Makefile
> +++ b/drivers/gpu/drm/xlnx/Makefile
> @@ -1,2 +1,3 @@
> zynqmp-dpsub-y := zynqmp_disp.o zynqmp_dpsub.o zynqmp_dp.o
> obj-$(CONFIG_DRM_ZYNQMP_DPSUB) += zynqmp-dpsub.o
> +obj-$(CONFIG_DRM_XLNX_DSI) += xlnx_dsi.o
> diff --git a/drivers/gpu/drm/xlnx/xlnx_dsi.c b/drivers/gpu/drm/xlnx/xlnx_dsi.c
> new file mode 100644
> index 0000000..a5291f3
> --- /dev/null
> +++ b/drivers/gpu/drm/xlnx/xlnx_dsi.c
> @@ -0,0 +1,456 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + *
> + * Xilinx FPGA MIPI DSI Tx Controller driver.
> + *
> + * Copyright (C) 2022 Xilinx, Inc.
> + *
> + * Author: Venkateshwar Rao G <vgannava@xxxxxxxxxx>
I noticed this is not the mail used in the s-o-b line.
> + *
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_bridge.h>
> +#include <drm/drm_mipi_dsi.h>
> +#include <drm/drm_modes.h>
> +#include <drm/drm_of.h>
> +#include <drm/drm_panel.h>
> +#include <drm/drm_print.h>
> +
> +/* DSI Tx IP registers */
> +#define XDSI_CCR 0x00
> +#define XDSI_CCR_COREENB BIT(0)
> +#define XDSI_CCR_SOFTRST BIT(1)
> +#define XDSI_CCR_CRREADY BIT(2)
> +#define XDSI_CCR_CMDMODE BIT(3)
> +#define XDSI_CCR_DFIFORST BIT(4)
> +#define XDSI_CCR_CMDFIFORST BIT(5)
> +#define XDSI_PCR 0x04
> +#define XDSI_PCR_LANES_MASK 3
> +#define XDSI_PCR_VIDEOMODE(x) (((x) & 0x3) << 3)
> +#define XDSI_PCR_VIDEOMODE_MASK (0x3 << 3)
GENMASK()?
Same for other XXX_MASK definitions below
> +#define XDSI_PCR_VIDEOMODE_SHIFT 3
> +#define XDSI_PCR_BLLPTYPE(x) ((x) << 5)
> +#define XDSI_PCR_BLLPMODE(x) ((x) << 6)
> +#define XDSI_PCR_PIXELFORMAT_MASK (0x3 << 11)
> +#define XDSI_PCR_PIXELFORMAT_SHIFT 11
> +#define XDSI_PCR_EOTPENABLE(x) ((x) << 13)
> +#define XDSI_GIER 0x20
> +#define XDSI_ISR 0x24
> +#define XDSI_IER 0x28
> +#define XDSI_STR 0x2C
> +#define XDSI_STR_RDY_SHPKT BIT(6)
> +#define XDSI_STR_RDY_LNGPKT BIT(7)
> +#define XDSI_STR_DFIFO_FULL BIT(8)
> +#define XDSI_STR_DFIFO_EMPTY BIT(9)
> +#define XDSI_STR_WAITFR_DATA BIT(10)
> +#define XDSI_STR_CMD_EXE_PGS BIT(11)
> +#define XDSI_STR_CCMD_PROC BIT(12)
> +#define XDSI_STR_LPKT_MASK (0x5 << 7)
> +#define XDSI_CMD 0x30
> +#define XDSI_CMD_QUEUE_PACKET(x) ((x) & GENMASK(23, 0))
> +#define XDSI_DFR 0x34
> +#define XDSI_TIME1 0x50
> +#define XDSI_TIME1_BLLP_BURST(x) ((x) & GENMASK(15, 0))
> +#define XDSI_TIME1_HSA(x) (((x) & GENMASK(15, 0)) << 16)
> +#define XDSI_TIME2 0x54
> +#define XDSI_TIME2_VACT(x) ((x) & GENMASK(15, 0))
> +#define XDSI_TIME2_HACT(x) (((x) & GENMASK(15, 0)) << 16)
> +#define XDSI_HACT_MULTIPLIER GENMASK(1, 0)
> +#define XDSI_TIME3 0x58
> +#define XDSI_TIME3_HFP(x) ((x) & GENMASK(15, 0))
> +#define XDSI_TIME3_HBP(x) (((x) & GENMASK(15, 0)) << 16)
> +#define XDSI_TIME4 0x5c
> +#define XDSI_TIME4_VFP(x) ((x) & GENMASK(7, 0))
> +#define XDSI_TIME4_VBP(x) (((x) & GENMASK(7, 0)) << 8)
> +#define XDSI_TIME4_VSA(x) (((x) & GENMASK(7, 0)) << 16)
> +#define XDSI_NUM_DATA_T 4
> +
> +/**
> + * struct xlnx_dsi - Xilinx DSI-TX core
> + * @bridge: DRM bridge structure
> + * @dsi_host: DSI host device
> + * @panel_bridge: Panel bridge structure
> + * @panel: DRM panel structure
> + * @dev: device structure
> + * @clks: clock source structure
> + * @iomem: Base address of DSI subsystem
> + * @mode_flags: DSI operation mode related flags
> + * @lanes: number of active data lanes supported by DSI controller
> + * @mul_factor: multiplication factor for HACT timing
> + * @format: pixel format for video mode of DSI controller
> + * @device_found: Flag to indicate device presence
> + */
> +struct xlnx_dsi {
> + struct drm_bridge bridge;
> + struct mipi_dsi_host dsi_host;
> + struct drm_bridge *panel_bridge;
> + struct drm_panel *panel;
It looks wrong that both a panel and a panel_bridge is required.
We should today only use the panel_bridge.
> + struct device *dev;
> + struct clk_bulk_data *clks;
> + void __iomem *iomem;
> + unsigned long mode_flags;
> + u32 lanes;
> + u32 mul_factor;
> + enum mipi_dsi_pixel_format format;
> + bool device_found;
> +};
> +
> +static const struct clk_bulk_data xdsi_clks[] = {
> + { .id = "s_axis_aclk" },
> + { .id = "dphy_clk_200M" },
> +};
> +
> +static inline struct xlnx_dsi *host_to_dsi(struct mipi_dsi_host *host)
> +{
> + return container_of(host, struct xlnx_dsi, dsi_host);
> +}
> +
> +static inline struct xlnx_dsi *bridge_to_dsi(struct drm_bridge *bridge)
> +{
> + return container_of(bridge, struct xlnx_dsi, bridge);
> +}
> +
> +static inline void xlnx_dsi_writel(void __iomem *base, int offset, u32 val)
> +{
> + writel(val, base + offset);
> +}
> +
> +static inline u32 xlnx_dsi_readl(void __iomem *base, int offset)
> +{
> + return readl(base + offset);
> +}
When I see implementations like this I wonder if a regmap would be
beneficial?
> +
> +static int xlnx_dsi_panel_or_bridge(struct xlnx_dsi *dsi,
> + struct device_node *node)
> +{
> + struct drm_bridge *panel_bridge;
> + struct drm_panel *panel;
> + struct device *dev = dsi->dev;
> + struct device_node *endpoint = dev->of_node;
> + int ret;
> +
> + ret = drm_of_find_panel_or_bridge(endpoint, 1, 0, &panel, &panel_bridge);
>From the documentation of drm_of_find_panel_or_bridge():
* This function is deprecated and should not be used in new drivers. Use
* devm_drm_of_get_bridge() instead.
Please update accordingly.
This will also avoid the panel/panel_bridge confusion.
> + if (ret < 0) {
> + dev_err(dsi->dev, "failed to find panel / bridge\n");
> + return ret;
> + }
> +
> + if (panel) {
> + panel_bridge = devm_drm_panel_bridge_add(dev, panel);
> + if (IS_ERR(panel_bridge))
> + return PTR_ERR(panel_bridge);
> + dsi->panel = panel;
> + }
> +
> + dsi->panel_bridge = panel_bridge;
> +
> + if (!dsi->panel_bridge) {
> + dev_err(dsi->dev, "panel not found\n");
> + return -EPROBE_DEFER;
> + }
> +
> + return 0;
> +}
> +
> +static int xlnx_dsi_host_attach(struct mipi_dsi_host *host,
> + struct mipi_dsi_device *device)
> +{
> + struct xlnx_dsi *dsi = host_to_dsi(host);
> + u32 reg;
> +
> + reg = xlnx_dsi_readl(dsi->iomem, XDSI_PCR);
> + dsi->lanes = reg & XDSI_PCR_LANES_MASK;
> + dsi->format = (reg & XDSI_PCR_PIXELFORMAT_MASK) >>
> + XDSI_PCR_PIXELFORMAT_SHIFT;
> + dsi->mode_flags = device->mode_flags;
> +
> + if (dsi->lanes != device->lanes) {
> + dev_err(dsi->dev, "Mismatch of lanes. panel = %d, DSI = %d\n",
> + device->lanes, dsi->lanes);
> + return -EINVAL;
> + }
> +
> + if (dsi->lanes > 4 || dsi->lanes < 1) {
> + dev_err(dsi->dev, "%d lanes : invalid xlnx,dsi-num-lanes\n",
> + dsi->lanes);
> + return -EINVAL;
> + }
> +
> + if (dsi->format != device->format) {
> + dev_err(dsi->dev, "Mismatch of format. panel = %d, DSI = %d\n",
> + device->format, dsi->format);
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> +static int xlnx_dsi_host_detach(struct mipi_dsi_host *host,
> + struct mipi_dsi_device *device)
> +{
> + struct xlnx_dsi *dsi = host_to_dsi(host);
> +
> + if (dsi->panel) {
> + drm_panel_disable(dsi->panel);
> + dsi->panel = NULL;
> + }
> +
> + return 0;
> +}
> +
> +static const struct mipi_dsi_host_ops xlnx_dsi_ops = {
> + .attach = xlnx_dsi_host_attach,
> + .detach = xlnx_dsi_host_detach,
> +};
> +
> +static void
> +xlnx_dsi_bridge_disable(struct drm_bridge *bridge,
> + struct drm_bridge_state *old_bridge_state)
> +{
> + struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
> + u32 reg = xlnx_dsi_readl(dsi->iomem, XDSI_CCR);
> +
> + reg &= ~XDSI_CCR_COREENB;
> + xlnx_dsi_writel(dsi->iomem, XDSI_CCR, reg);
> + dev_dbg(dsi->dev, "DSI-Tx is disabled\n");
> +}
> +
> +static void
> +xlnx_dsi_bridge_mode_set(struct drm_bridge *bridge,
> + const struct drm_display_mode *mode,
> + const struct drm_display_mode *adjusted_mode)
> +{
> + struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
> + u32 reg, video_mode;
> +
> + reg = xlnx_dsi_readl(dsi->iomem, XDSI_PCR);
> + video_mode = (reg & XDSI_PCR_VIDEOMODE_MASK) >> XDSI_PCR_VIDEOMODE_SHIFT;
> +
> + if (!video_mode && (dsi->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE)) {
> + reg = XDSI_TIME1_HSA(adjusted_mode->hsync_end -
> + adjusted_mode->hsync_start);
> + xlnx_dsi_writel(dsi->iomem, XDSI_TIME1, reg);
> + }
> +
> + reg = XDSI_TIME4_VFP(adjusted_mode->vsync_start -
> + adjusted_mode->vdisplay) |
> + XDSI_TIME4_VBP(adjusted_mode->vtotal -
> + adjusted_mode->vsync_end) |
> + XDSI_TIME4_VSA(adjusted_mode->vsync_end -
> + adjusted_mode->vsync_start);
> + xlnx_dsi_writel(dsi->iomem, XDSI_TIME4, reg);
> +
> + reg = XDSI_TIME3_HFP(adjusted_mode->hsync_start -
> + adjusted_mode->hdisplay) |
> + XDSI_TIME3_HBP(adjusted_mode->htotal -
> + adjusted_mode->hsync_end);
> + xlnx_dsi_writel(dsi->iomem, XDSI_TIME3, reg);
> + dev_dbg(dsi->dev, "mul factor for parsed datatype is = %d\n",
> + (dsi->mul_factor) / 100);
> +
> + if ((adjusted_mode->hdisplay & XDSI_HACT_MULTIPLIER) != 0)
> + dev_warn(dsi->dev, "Incorrect HACT will be programmed\n");
Maybe catch this in a mode_valid() operation?
> +
> + reg = XDSI_TIME2_HACT((adjusted_mode->hdisplay) * (dsi->mul_factor) / 100) |
> + XDSI_TIME2_VACT(adjusted_mode->vdisplay);
> +
> + xlnx_dsi_writel(dsi->iomem, XDSI_PCR, XDSI_PCR_VIDEOMODE(BIT(0)));
> +}
> +
> +static void xlnx_dsi_bridge_enable(struct drm_bridge *bridge,
> + struct drm_bridge_state *old_bridge_state)
> +{
> + struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
> + u32 reg;
> +
> + reg = xlnx_dsi_readl(dsi->iomem, XDSI_CCR);
> + reg |= XDSI_CCR_COREENB;
> + xlnx_dsi_writel(dsi->iomem, XDSI_CCR, reg);
> + dev_dbg(dsi->dev, "MIPI DSI Tx controller is enabled.\n");
> +}
> +
> +static int xlnx_dsi_bridge_attach(struct drm_bridge *bridge,
> + enum drm_bridge_attach_flags flags)
> +{
> + struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
> +
> + if (!bridge->encoder) {
> + DRM_ERROR("Parent encoder object not found\n");
DRM_ERROR and friends are deprecated. Use drm_xxx or dev_xxx if possible, otherwise
fallback to pr_err.
> + return -ENODEV;
> + }
> +
> + /* Set the encoder type as caller does not know it */
> + bridge->encoder->encoder_type = DRM_MODE_ENCODER_DSI;
> +
> + if (!dsi->device_found) {
> + int ret;
> +
> + ret = xlnx_dsi_panel_or_bridge(dsi, dsi->dev->of_node);
> + if (ret) {
> + dev_err(dsi->dev, "dsi_panel_or_bridge failed\n");
> + return ret;
> + }
> +
> + dsi->device_found = true;
> + }
> +
> + /* Attach the panel-bridge to the dsi bridge */
> + return drm_bridge_attach(bridge->encoder, dsi->panel_bridge, bridge,
> + flags);
> +}
> +
> +static void xlnx_dsi_bridge_detach(struct drm_bridge *bridge)
> +{
> + struct xlnx_dsi *dsi = bridge_to_dsi(bridge);
> +
> + drm_of_panel_bridge_remove(dsi->dev->of_node, 1, 0);
> +}
> +
> +static const struct drm_bridge_funcs xlnx_dsi_bridge_funcs = {
> + .mode_set = xlnx_dsi_bridge_mode_set,
>From the documentation of the mode_set operation:
* This is deprecated, do not use!
* New drivers shall set their mode in the
* &drm_bridge_funcs.atomic_enable operation.
Please adjust accordingly.
> + .atomic_enable = xlnx_dsi_bridge_enable,
> + .atomic_disable = xlnx_dsi_bridge_disable,
> + .attach = xlnx_dsi_bridge_attach,
> + .detach = xlnx_dsi_bridge_detach,
> +};
For a new bridge please implement all the mandatory atomic operations.
You will need at least:
.atomic_get_output_bus_fmts = xlnx_dsi_bridge_get_output_bus_fmts,
.atomic_get_input_bus_fmts = xlnx_dsi_bridge_get_input_bus_fmts,
.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,
};
> +
> +static int xlnx_dsi_parse_dt(struct xlnx_dsi *dsi)
> +{
> + struct device *dev = dsi->dev;
> + struct device_node *node = dev->of_node;
> + int ret;
> + u32 datatype;
> + static const int xdsi_mul_fact[XDSI_NUM_DATA_T] = {300, 225, 225, 200};
> +
> + /*
> + * Used as a multiplication factor for HACT based on used
> + * DSI data type.
> + *
> + * e.g. for RGB666_L datatype and 1920x1080 resolution,
> + * the Hact (WC) would be as follows -
> + * 1920 pixels * 18 bits per pixel / 8 bits per byte
> + * = 1920 pixels * 2.25 bytes per pixel = 4320 bytes.
> + *
> + * Data Type - Multiplication factor
> + * RGB888 - 3
> + * RGB666_L - 2.25
> +- * RGB666_P - 2.25
> + * RGB565 - 2
> + *
> + * Since the multiplication factor is a floating number,
> + * a 100x multiplication factor is used.
> + */
> + ret = of_property_read_u32(node, "xlnx,dsi-data-type", &datatype);
> + if (ret < 0) {
> + dev_err(dsi->dev, "missing xlnx,dsi-data-type property\n");
> + return ret;
> + }
> + dsi->format = datatype;
> + if (datatype > MIPI_DSI_FMT_RGB565) {
> + dev_err(dsi->dev, "Invalid xlnx,dsi-data-type string\n");
> + return -EINVAL;
> + }
> + dsi->mul_factor = xdsi_mul_fact[datatype];
> +
> + dev_dbg(dsi->dev, "DSI controller num lanes = %d", dsi->lanes);
> + dev_dbg(dsi->dev, "DSI controller datatype = %d\n", datatype);
> +
> + return 0;
> +}
> +
> +static int xlnx_dsi_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + struct xlnx_dsi *dsi;
> + int num_clks = ARRAY_SIZE(xdsi_clks);
> + int ret;
> +
> + dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> + if (!dsi)
> + return -ENOMEM;
> +
> + dsi->dev = dev;
> + dsi->clks = devm_kmemdup(dev, xdsi_clks, sizeof(xdsi_clks),
> + GFP_KERNEL);
> + if (!dsi->clks)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + dsi->iomem = devm_ioremap_resource(dev, res);
> + if (IS_ERR(dsi->iomem))
> + return PTR_ERR(dsi->iomem);
> +
> + ret = clk_bulk_get(dev, num_clks, dsi->clks);
> + if (ret)
> + return ret;
> +
> + ret = xlnx_dsi_parse_dt(dsi);
> + if (ret)
> + return ret;
> +
> + ret = clk_bulk_prepare_enable(num_clks, dsi->clks);
> + if (ret)
> + goto err_clk_put;
> +
> + platform_set_drvdata(pdev, dsi);
> + dsi->dsi_host.ops = &xlnx_dsi_ops;
> + dsi->dsi_host.dev = dev;
> +
> + ret = mipi_dsi_host_register(&dsi->dsi_host);
> + if (ret) {
> + dev_err(dev, "Failed to register MIPI host: %d\n", ret);
> + goto err_clk_put;
> + }
> +
> + dsi->bridge.driver_private = dsi;
> + dsi->bridge.funcs = &xlnx_dsi_bridge_funcs;
> +#ifdef CONFIG_OF
The driver depends on CONFIG_OF - so no need to check it here.
> + dsi->bridge.of_node = pdev->dev.of_node;
> +#endif
> +
> + drm_bridge_add(&dsi->bridge);
> +
> +err_clk_put:
> + clk_bulk_put(num_clks, dsi->clks);
> +
> + return ret;
> +}
> +
> +static int xlnx_dsi_remove(struct platform_device *pdev)
> +{
> + struct xlnx_dsi *dsi = platform_get_drvdata(pdev);
> + int num_clks = ARRAY_SIZE(xdsi_clks);
> +
> + mipi_dsi_host_unregister(&dsi->dsi_host);
> + clk_bulk_disable_unprepare(num_clks, dsi->clks);
> + clk_bulk_put(num_clks, dsi->clks);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id xlnx_dsi_of_match[] = {
> + { .compatible = "xlnx,dsi-tx-v2.0"},
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, xlnx_dsi_of_match);
> +
> +static struct platform_driver dsi_driver = {
> + .probe = xlnx_dsi_probe,
> + .remove = xlnx_dsi_remove,
> + .driver = {
> + .name = "xlnx-dsi",
> + .of_match_table = xlnx_dsi_of_match,
> + },
> +};
> +
> +module_platform_driver(dsi_driver);
> +
> +MODULE_AUTHOR("Venkateshwar Rao G <vgannava@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Xilinx MIPI DSI host controller driver");
> +MODULE_LICENSE("GPL");
> --
> 1.8.3.1
