This adds a very small and simple driver to read a virtual display characteristic from the device tree and reflect it back into DRM so a display driver in a virtual environment knows how to configure its output.
This was created for the ARM RTSM aemv8a emulator as a way forward to convert all ARM reference designs to use the PL11x DRM driver.
Cc: Liviu Dudau Liviu.Dudau@arm.com Cc: Ryan Harkin ryan.harkin@linaro.org Signed-off-by: Linus Walleij linus.walleij@linaro.org --- drivers/gpu/drm/bridge/Kconfig | 10 ++ drivers/gpu/drm/bridge/Makefile | 1 + drivers/gpu/drm/bridge/virtual-display.c | 186 +++++++++++++++++++++++ 3 files changed, 197 insertions(+) create mode 100644 drivers/gpu/drm/bridge/virtual-display.c
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig index fa2c7997e2fd..cfb61305b3f6 100644 --- a/drivers/gpu/drm/bridge/Kconfig +++ b/drivers/gpu/drm/bridge/Kconfig @@ -126,6 +126,16 @@ config DRM_TI_TFP410 ---help--- Texas Instruments TFP410 DVI/HDMI Transmitter driver
+config DRM_VIRTUAL_DISPLAY_BRIDGE + tristate "Virtual Display Bridge support" + depends on OF + select DRM_KMS_HELPER + select VIDEOMODE_HELPERS + help + Support for virtualized environments where the avilable + resolution is controlled by software configuration in + the device tree. + source "drivers/gpu/drm/bridge/analogix/Kconfig"
source "drivers/gpu/drm/bridge/adv7511/Kconfig" diff --git a/drivers/gpu/drm/bridge/Makefile b/drivers/gpu/drm/bridge/Makefile index 35f88d48ec20..2bdf67d98972 100644 --- a/drivers/gpu/drm/bridge/Makefile +++ b/drivers/gpu/drm/bridge/Makefile @@ -14,4 +14,5 @@ obj-$(CONFIG_DRM_TOSHIBA_TC358767) += tc358767.o obj-$(CONFIG_DRM_ANALOGIX_DP) += analogix/ obj-$(CONFIG_DRM_I2C_ADV7511) += adv7511/ obj-$(CONFIG_DRM_TI_TFP410) += ti-tfp410.o +obj-$(CONFIG_DRM_VIRTUAL_DISPLAY_BRIDGE) += virtual-display.o obj-y += synopsys/ diff --git a/drivers/gpu/drm/bridge/virtual-display.c b/drivers/gpu/drm/bridge/virtual-display.c new file mode 100644 index 000000000000..ab55b3d6be8a --- /dev/null +++ b/drivers/gpu/drm/bridge/virtual-display.c @@ -0,0 +1,186 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * (C) Copyright 2018 Linus Walleij linus.walleij@linaro.org + */ + +#include <linux/module.h> +#include <drm/drmP.h> +#include <drm/drm_atomic_helper.h> +#include <drm/drm_crtc_helper.h> +#include <drm/drm_modes.h> +#include <video/of_display_timing.h> + +struct virtenc { + struct device *dev; + struct drm_device *drm; + struct drm_bridge bridge; + struct drm_connector connector; + struct drm_display_mode mode; + u32 bus_flags; +}; + +static inline struct virtenc *bridge_to_virtenc(struct drm_bridge *bridge) +{ + return container_of(bridge, struct virtenc, bridge); +} + +static inline struct virtenc *connector_to_virtenc(struct drm_connector *con) +{ + return container_of(con, struct virtenc, connector); +} + +static enum drm_connector_status +virtenc_connector_detect(struct drm_connector *connector, bool force) +{ + return connector_status_connected; +} + +static const struct drm_connector_funcs virtenc_connector_funcs = { + .detect = virtenc_connector_detect, + .fill_modes = drm_helper_probe_single_connector_modes, + .destroy = drm_connector_cleanup, + .reset = drm_atomic_helper_connector_reset, + .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, + .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, +}; + +static int virtenc_get_modes(struct drm_connector *connector) +{ + struct virtenc *virtenc = connector_to_virtenc(connector); + struct drm_display_mode *mode = drm_mode_create(virtenc->drm); + u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24; + int ret; + + drm_mode_copy(mode, &virtenc->mode); + mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED; + mode->width_mm = 80; + mode->height_mm = 60; + drm_mode_set_name(mode); + + drm_mode_probed_add(connector, mode); + ret = drm_display_info_set_bus_formats(&connector->display_info, + &bus_format, 1); + if (ret) + return ret; + + return 1; +} + +static enum drm_mode_status virtenc_mode_valid(struct drm_connector *connector, + struct drm_display_mode *mode) +{ + return MODE_OK; +} + +static const struct drm_connector_helper_funcs +virtenc_connector_helper_funcs = { + .get_modes = virtenc_get_modes, + .mode_valid = virtenc_mode_valid, +}; + +static void virtenc_bridge_disable(struct drm_bridge *bridge) +{ +} + +static void virtenc_bridge_enable(struct drm_bridge *bridge) +{ +} + +static void virtenc_bridge_mode_set(struct drm_bridge *bridge, + struct drm_display_mode *mode, + struct drm_display_mode *adj) +{ +} + +static int virtenc_bridge_attach(struct drm_bridge *bridge) +{ + struct virtenc *virtenc = bridge_to_virtenc(bridge); + struct drm_device *drm = bridge->dev; + int ret; + + virtenc->drm = drm; + drm_connector_helper_add(&virtenc->connector, + &virtenc_connector_helper_funcs); + + if (!drm_core_check_feature(drm, DRIVER_ATOMIC)) { + dev_err(virtenc->dev, + "Virtual Display bridge driver is only compatible with DRM devices supporting atomic updates\n"); + return -ENOTSUPP; + } + + ret = drm_connector_init(drm, &virtenc->connector, + &virtenc_connector_funcs, + DRM_MODE_CONNECTOR_VIRTUAL); + if (ret) + return ret; + + virtenc->connector.polled = DRM_CONNECTOR_POLL_CONNECT; + + drm_mode_connector_attach_encoder(&virtenc->connector, bridge->encoder); + + return 0; +} + +static const struct drm_bridge_funcs virtenc_bridge_funcs = { + .attach = virtenc_bridge_attach, + .mode_set = virtenc_bridge_mode_set, + .disable = virtenc_bridge_disable, + .enable = virtenc_bridge_enable, +}; + +static int virtenc_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct virtenc *virtenc; + int ret; + + virtenc = devm_kzalloc(dev, sizeof(*virtenc), GFP_KERNEL); + if (!virtenc) + return -ENOMEM; + + ret = of_get_drm_display_mode(np, &virtenc->mode, + &virtenc->bus_flags, + 0); + if (ret) + return ret; + + virtenc->dev = dev; + virtenc->bridge.funcs = &virtenc_bridge_funcs; + virtenc->bridge.of_node = dev->of_node; + drm_bridge_add(&virtenc->bridge); + platform_set_drvdata(pdev, virtenc); + dev_info(dev, "added virtual display bridge\n"); + + return 0; +} + +static int virtenc_remove(struct platform_device *pdev) + +{ + struct virtenc *virtenc = platform_get_drvdata(pdev); + + drm_bridge_remove(&virtenc->bridge); + + return 0; +} + +static const struct of_device_id virtenc_dt_ids[] = { + { .compatible = "virtual-display-bridge", }, + { } +}; +MODULE_DEVICE_TABLE(of, virtenc_dt_ids); + +static struct platform_driver virtenc_driver = { + .driver = { + .name = "virtenc", + .of_match_table = virtenc_dt_ids, + }, + .probe = virtenc_probe, + .remove = virtenc_remove, +}; +module_platform_driver(virtenc_driver); + +MODULE_AUTHOR("Linus Walleij linus.walleij@linaro.org"); +MODULE_DESCRIPTION("Virtual Display Bridge"); +MODULE_LICENSE("GPL");