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Commit 1c7c5fd9 authored by Haneen Mohammed's avatar Haneen Mohammed Committed by Gustavo Padovan
Browse files

drm/vkms: Introduce basic VKMS driver 



This patch introduces Virtual Kernel Mode-Setting (VKMS) driver. It
creates a very basic kms driver with 1 crtc/encoder/connector/plane.

VKMS driver would be useful for testing, or for running X (or similar)
on headless machines and be able to still use the GPU. Thus it enables
a virtual display without the need for hardware display capability.

Signed-off-by: default avatarHaneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarGustavo Padovan <gustavo.padovan@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180514143346.GA21695@haneen-vb
parent c51756d5

drivers/gpu/drm/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -213,6 +213,12 @@ config DRM_VGEM 
	  as used by Mesa's software renderer for enhanced performance.

	  If M is selected the module will be called vgem.



config DRM_VKMS

	tristate "Virtual KMS"

	depends on DRM

	help

	  Choose this option to get a virtual kernal mode-setting driver.

	  If M is selected the module will be called vkms.



source "drivers/gpu/drm/exynos/Kconfig"

drivers/gpu/drm/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ obj-$(CONFIG_DRM_SAVAGE)+= savage/ 
obj-$(CONFIG_DRM_VMWGFX)+= vmwgfx/

obj-$(CONFIG_DRM_VIA)	+=via/

obj-$(CONFIG_DRM_VGEM)	+= vgem/

obj-$(CONFIG_DRM_VKMS)	+= vkms/

obj-$(CONFIG_DRM_NOUVEAU) +=nouveau/

obj-$(CONFIG_DRM_EXYNOS) +=exynos/

obj-$(CONFIG_DRM_ROCKCHIP) +=rockchip/

drivers/gpu/drm/vkms/Makefile

0 → 100644
+3 −0
Original line number Diff line number Diff line 
vkms-y := vkms_drv.o



obj-$(CONFIG_DRM_VKMS) += vkms.o

drivers/gpu/drm/vkms/vkms_drv.c

0 → 100644
+146 −0
Original line number Diff line number Diff line 
/*

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 */



#include <linux/module.h>

#include <drm/drmP.h>

#include <drm/drm_gem.h>

#include <drm/drm_crtc_helper.h>

#include "vkms_drv.h"



#define DRIVER_NAME	"vkms"

#define DRIVER_DESC	"Virtual Kernel Mode Setting"

#define DRIVER_DATE	"20180514"

#define DRIVER_MAJOR	1

#define DRIVER_MINOR	0



static struct vkms_device *vkms_device;



static const struct file_operations vkms_driver_fops = {

	.owner		= THIS_MODULE,

	.open		= drm_open,

	.mmap		= drm_gem_mmap,

	.unlocked_ioctl	= drm_ioctl,

	.compat_ioctl	= drm_compat_ioctl,

	.poll		= drm_poll,

	.read		= drm_read,

	.llseek		= no_llseek,

	.release	= drm_release,

};



static void vkms_release(struct drm_device *dev)

{

	struct vkms_device *vkms = container_of(dev, struct vkms_device, drm);



	platform_device_unregister(vkms->platform);

	drm_mode_config_cleanup(&vkms->drm);

	drm_dev_fini(&vkms->drm);

}



struct drm_driver vkms_driver = {

	.driver_features	= DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,

	.release		= vkms_release,

	.fops			= &vkms_driver_fops,



	.name			= DRIVER_NAME,

	.desc			= DRIVER_DESC,

	.date			= DRIVER_DATE,

	.major			= DRIVER_MAJOR,

	.minor			= DRIVER_MINOR,

};



static const u32 vkms_formats[] = {

	DRM_FORMAT_XRGB8888,

};



static void vkms_connector_destroy(struct drm_connector *connector)

{

	drm_connector_unregister(connector);

	drm_connector_cleanup(connector);

}



static const struct drm_connector_funcs vkms_connector_funcs = {

	.fill_modes = drm_helper_probe_single_connector_modes,

	.destroy = vkms_connector_destroy,

};



static int __init vkms_init(void)

{

	int ret;



	vkms_device = kzalloc(sizeof(*vkms_device), GFP_KERNEL);

	if (!vkms_device)

		return -ENOMEM;



	ret = drm_dev_init(&vkms_device->drm, &vkms_driver, NULL);

	if (ret)

		goto out_free;



	vkms_device->platform =

		platform_device_register_simple(DRIVER_NAME, -1, NULL, 0);

	if (IS_ERR(vkms_device->platform)) {

		ret = PTR_ERR(vkms_device->platform);

		goto out_fini;

	}



	drm_mode_config_init(&vkms_device->drm);



	ret = drm_connector_init(&vkms_device->drm, &vkms_device->connector,

				 &vkms_connector_funcs,

				 DRM_MODE_CONNECTOR_VIRTUAL);

	if (ret < 0) {

		DRM_ERROR("Failed to init connector\n");

		goto out_unregister;

	}



	ret = drm_simple_display_pipe_init(&vkms_device->drm,

					   &vkms_device->pipe,

					   NULL,

					   vkms_formats,

					   ARRAY_SIZE(vkms_formats),

					   NULL,

					   &vkms_device->connector);

	if (ret < 0) {

		DRM_ERROR("Cannot setup simple display pipe\n");

		goto out_unregister;

	}



	ret = drm_dev_register(&vkms_device->drm, 0);

	if (ret)

		goto out_unregister;



	drm_connector_register(&vkms_device->connector);



	return 0;



out_unregister:

	platform_device_unregister(vkms_device->platform);

out_fini:

	drm_dev_fini(&vkms_device->drm);

out_free:

	kfree(vkms_device);



	return ret;

}



static void __exit vkms_exit(void)

{

	if (!vkms_device) {

		DRM_INFO("vkms_device is NULL.\n");

		return;

	}



	drm_dev_unregister(&vkms_device->drm);

	drm_dev_put(&vkms_device->drm);



	kfree(vkms_device);

}



module_init(vkms_init);

module_exit(vkms_exit);



MODULE_DESCRIPTION(DRIVER_DESC);

MODULE_LICENSE("GPL");

drivers/gpu/drm/vkms/vkms_drv.h

0 → 100644
+13 −0
Original line number Diff line number Diff line 
#ifndef _VKMS_DRV_H_

#define _VKMS_DRV_H_



#include <drm/drm_simple_kms_helper.h>



struct vkms_device {

	struct drm_device drm;

	struct platform_device *platform;

	struct drm_simple_display_pipe pipe;

	struct drm_connector connector;

};



#endif /* _VKMS_DRV_H_ */