This the beginning of an API for in-kernel clients. First out is a way to get a framebuffer backed by a dumb buffer.
Only GEM drivers are supported. The original idea of using an exported dma-buf was dropped because it also creates an anonomous file descriptor which doesn't work when the buffer is created from a kernel thread. The easy way out is to use drm_driver.gem_prime_vmap to get the virtual address, which requires a GEM object. This excludes the vmwgfx driver which is the only non-GEM driver apart from the legacy ones. A solution for vmwgfx will have to be worked out later if it wants to support the client API which it probably will when we have a bootsplash client.
Signed-off-by: Noralf Trønnes noralf@tronnes.org Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch --- Documentation/gpu/drm-client.rst | 12 ++ Documentation/gpu/index.rst | 1 + drivers/gpu/drm/Makefile | 2 +- drivers/gpu/drm/drm_client.c | 289 +++++++++++++++++++++++++++++++++++++++ drivers/gpu/drm/drm_drv.c | 1 + include/drm/drm_client.h | 76 ++++++++++ include/drm/drm_device.h | 7 + 7 files changed, 387 insertions(+), 1 deletion(-) create mode 100644 Documentation/gpu/drm-client.rst create mode 100644 drivers/gpu/drm/drm_client.c create mode 100644 include/drm/drm_client.h
diff --git a/Documentation/gpu/drm-client.rst b/Documentation/gpu/drm-client.rst new file mode 100644 index 000000000000..7e672063e7eb --- /dev/null +++ b/Documentation/gpu/drm-client.rst @@ -0,0 +1,12 @@ +================= +Kernel clients +================= + +.. kernel-doc:: drivers/gpu/drm/drm_client.c + :doc: overview + +.. kernel-doc:: include/drm/drm_client.h + :internal: + +.. kernel-doc:: drivers/gpu/drm/drm_client.c + :export: diff --git a/Documentation/gpu/index.rst b/Documentation/gpu/index.rst index 00288f34c5a6..1fcf8e851e15 100644 --- a/Documentation/gpu/index.rst +++ b/Documentation/gpu/index.rst @@ -10,6 +10,7 @@ Linux GPU Driver Developer's Guide drm-kms drm-kms-helpers drm-uapi + drm-client drivers vga-switcheroo vgaarbiter diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile index 69c13517ea3a..d6657a61d037 100644 --- a/drivers/gpu/drm/Makefile +++ b/drivers/gpu/drm/Makefile @@ -18,7 +18,7 @@ drm-y := drm_auth.o drm_bufs.o drm_cache.o \ drm_encoder.o drm_mode_object.o drm_property.o \ drm_plane.o drm_color_mgmt.o drm_print.o \ drm_dumb_buffers.o drm_mode_config.o drm_vblank.o \ - drm_syncobj.o drm_lease.o drm_writeback.o + drm_syncobj.o drm_lease.o drm_writeback.o drm_client.o
drm-$(CONFIG_DRM_LIB_RANDOM) += lib/drm_random.o drm-$(CONFIG_DRM_VM) += drm_vm.o diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c new file mode 100644 index 000000000000..9c9b8ac7aea3 --- /dev/null +++ b/drivers/gpu/drm/drm_client.c @@ -0,0 +1,289 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2018 Noralf Trønnes + */ + +#include <linux/list.h> +#include <linux/mutex.h> +#include <linux/seq_file.h> +#include <linux/slab.h> + +#include <drm/drm_client.h> +#include <drm/drm_debugfs.h> +#include <drm/drm_device.h> +#include <drm/drm_drv.h> +#include <drm/drm_file.h> +#include <drm/drm_fourcc.h> +#include <drm/drm_gem.h> +#include <drm/drm_mode.h> +#include <drm/drm_print.h> +#include <drm/drmP.h> + +#include "drm_crtc_internal.h" +#include "drm_internal.h" + +/** + * DOC: overview + * + * This library provides support for clients running in the kernel like fbdev and bootsplash. + * Currently it's only partially implemented, just enough to support fbdev. + * + * GEM drivers which provide a GEM based dumb buffer with a virtual address are supported. + */ + +static int drm_client_open(struct drm_client_dev *client) +{ + struct drm_device *dev = client->dev; + struct drm_file *file; + + file = drm_file_alloc(dev->primary); + if (IS_ERR(file)) + return PTR_ERR(file); + + mutex_lock(&dev->filelist_mutex); + list_add(&file->lhead, &dev->filelist_internal); + mutex_unlock(&dev->filelist_mutex); + + client->file = file; + + return 0; +} + +static void drm_client_close(struct drm_client_dev *client) +{ + struct drm_device *dev = client->dev; + + mutex_lock(&dev->filelist_mutex); + list_del(&client->file->lhead); + mutex_unlock(&dev->filelist_mutex); + + drm_file_free(client->file); +} +EXPORT_SYMBOL(drm_client_close); + +/** + * drm_client_new - Create a DRM client + * @dev: DRM device + * @client: DRM client + * @name: Client name + * + * Use drm_client_put() to free the client. + * + * Returns: + * Zero on success or negative error code on failure. + */ +int drm_client_new(struct drm_device *dev, struct drm_client_dev *client, + const char *name) +{ + int ret; + + if (!drm_core_check_feature(dev, DRIVER_MODESET) || + !dev->driver->dumb_create || !dev->driver->gem_prime_vmap) + return -ENOTSUPP; + + client->dev = dev; + client->name = name; + + ret = drm_client_open(client); + if (ret) + return ret; + + drm_dev_get(dev); + + return 0; +} +EXPORT_SYMBOL(drm_client_new); + +/** + * drm_client_release - Release DRM client resources + * @client: DRM client + * + * Releases resources by closing the &drm_file that was opened by drm_client_new(). + * It is called automatically if the &drm_client_funcs.unregister callback is _not_ set. + * + * This function should only be called from the unregister callback. An exception + * is fbdev which cannot free the buffer if userspace has open file descriptors. + * + * Note: + * Clients cannot initiate a release by themselves. This is done to keep the code simple. + * The driver has to be unloaded before the client can be unloaded. + */ +void drm_client_release(struct drm_client_dev *client) +{ + struct drm_device *dev = client->dev; + + DRM_DEV_DEBUG_KMS(dev->dev, "%s\n", client->name); + + drm_client_close(client); + drm_dev_put(dev); +} +EXPORT_SYMBOL(drm_client_release); + +static void drm_client_buffer_delete(struct drm_client_buffer *buffer) +{ + struct drm_device *dev = buffer->client->dev; + + if (buffer->vaddr && dev->driver->gem_prime_vunmap) + dev->driver->gem_prime_vunmap(buffer->gem, buffer->vaddr); + + if (buffer->gem) + drm_gem_object_put_unlocked(buffer->gem); + + drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file); + kfree(buffer); +} + +static struct drm_client_buffer * +drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format) +{ + struct drm_mode_create_dumb dumb_args = { }; + struct drm_device *dev = client->dev; + struct drm_client_buffer *buffer; + struct drm_gem_object *obj; + void *vaddr; + int ret; + + buffer = kzalloc(sizeof(*buffer), GFP_KERNEL); + if (!buffer) + return ERR_PTR(-ENOMEM); + + buffer->client = client; + + dumb_args.width = width; + dumb_args.height = height; + dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8; + ret = drm_mode_create_dumb(dev, &dumb_args, client->file); + if (ret) + goto err_free; + + buffer->handle = dumb_args.handle; + buffer->pitch = dumb_args.pitch; + + obj = drm_gem_object_lookup(client->file, dumb_args.handle); + if (!obj) { + ret = -ENOENT; + goto err_delete; + } + + buffer->gem = obj; + + /* + * FIXME: The dependency on GEM here isn't required, we could + * convert the driver handle to a dma-buf instead and use the + * backend-agnostic dma-buf vmap support instead. This would + * require that the handle2fd prime ioctl is reworked to pull the + * fd_install step out of the driver backend hooks, to make that + * final step optional for internal users. + */ + vaddr = dev->driver->gem_prime_vmap(obj); + if (!vaddr) { + ret = -ENOMEM; + goto err_delete; + } + + buffer->vaddr = vaddr; + + return buffer; + +err_delete: + drm_client_buffer_delete(buffer); +err_free: + kfree(buffer); + + return ERR_PTR(ret); +} + +static void drm_client_buffer_rmfb(struct drm_client_buffer *buffer) +{ + int ret; + + if (!buffer->fb) + return; + + ret = drm_mode_rmfb(buffer->client->dev, buffer->fb->base.id, buffer->client->file); + if (ret) + DRM_DEV_ERROR(buffer->client->dev->dev, + "Error removing FB:%u (%d)\n", buffer->fb->base.id, ret); + + buffer->fb = NULL; +} + +static int drm_client_buffer_addfb(struct drm_client_buffer *buffer, + u32 width, u32 height, u32 format) +{ + struct drm_client_dev *client = buffer->client; + struct drm_mode_fb_cmd fb_req = { }; + const struct drm_format_info *info; + int ret; + + info = drm_format_info(format); + fb_req.bpp = info->cpp[0] * 8; + fb_req.depth = info->depth; + fb_req.width = width; + fb_req.height = height; + fb_req.handle = buffer->handle; + fb_req.pitch = buffer->pitch; + + ret = drm_mode_addfb(client->dev, &fb_req, client->file); + if (ret) + return ret; + + buffer->fb = drm_framebuffer_lookup(client->dev, buffer->client->file, fb_req.fb_id); + if (WARN_ON(!buffer->fb)) + return -ENOENT; + + /* drop the reference we picked up in framebuffer lookup */ + drm_framebuffer_put(buffer->fb); + + strscpy(buffer->fb->comm, client->name, TASK_COMM_LEN); + + return 0; +} + +/** + * drm_client_framebuffer_create - Create a client framebuffer + * @client: DRM client + * @width: Framebuffer width + * @height: Framebuffer height + * @format: Buffer format + * + * This function creates a &drm_client_buffer which consists of a + * &drm_framebuffer backed by a dumb buffer. + * Call drm_client_framebuffer_delete() to free the buffer. + * + * Returns: + * Pointer to a client buffer or an error pointer on failure. + */ +struct drm_client_buffer * +drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format) +{ + struct drm_client_buffer *buffer; + int ret; + + buffer = drm_client_buffer_create(client, width, height, format); + if (IS_ERR(buffer)) + return buffer; + + ret = drm_client_buffer_addfb(buffer, width, height, format); + if (ret) { + drm_client_buffer_delete(buffer); + return ERR_PTR(ret); + } + + return buffer; +} +EXPORT_SYMBOL(drm_client_framebuffer_create); + +/** + * drm_client_framebuffer_delete - Delete a client framebuffer + * @buffer: DRM client buffer (can be NULL) + */ +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer) +{ + if (!buffer) + return; + + drm_client_buffer_rmfb(buffer); + drm_client_buffer_delete(buffer); +} +EXPORT_SYMBOL(drm_client_framebuffer_delete); diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 7af748ed1c58..e7ff0b03328b 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -505,6 +505,7 @@ int drm_dev_init(struct drm_device *dev, dev->driver = driver;
INIT_LIST_HEAD(&dev->filelist); + INIT_LIST_HEAD(&dev->filelist_internal); INIT_LIST_HEAD(&dev->ctxlist); INIT_LIST_HEAD(&dev->vmalist); INIT_LIST_HEAD(&dev->maplist); diff --git a/include/drm/drm_client.h b/include/drm/drm_client.h new file mode 100644 index 000000000000..e366f95d4414 --- /dev/null +++ b/include/drm/drm_client.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _DRM_CLIENT_H_ +#define _DRM_CLIENT_H_ + +#include <linux/types.h> + +struct drm_device; +struct drm_file; +struct drm_framebuffer; +struct drm_gem_object; + +/** + * struct drm_client_dev - DRM client instance + */ +struct drm_client_dev { + /** + * @dev: DRM device + */ + struct drm_device *dev; + + /** + * @name: Name of the client. + */ + const char *name; + + /** + * @file: DRM file + */ + struct drm_file *file; +}; + +int drm_client_new(struct drm_device *dev, struct drm_client_dev *client, + const char *name); +void drm_client_release(struct drm_client_dev *client); + +/** + * struct drm_client_buffer - DRM client buffer + */ +struct drm_client_buffer { + /** + * @client: DRM client + */ + struct drm_client_dev *client; + + /** + * @handle: Buffer handle + */ + u32 handle; + + /** + * @pitch: Buffer pitch + */ + u32 pitch; + + /** + * @gem: GEM object backing this buffer + */ + struct drm_gem_object *gem; + + /** + * @vaddr: Virtual address for the buffer + */ + void *vaddr; + + /** + * @fb: DRM framebuffer + */ + struct drm_framebuffer *fb; +}; + +struct drm_client_buffer * +drm_client_framebuffer_create(struct drm_client_dev *client, u32 width, u32 height, u32 format); +void drm_client_framebuffer_delete(struct drm_client_buffer *buffer); + +#endif diff --git a/include/drm/drm_device.h b/include/drm/drm_device.h index 858ba19a3e29..9e29976d4e98 100644 --- a/include/drm/drm_device.h +++ b/include/drm/drm_device.h @@ -74,6 +74,13 @@ struct drm_device { struct mutex filelist_mutex; struct list_head filelist;
+ /** + * @filelist_internal: + * + * List of open DRM files for in-kernel clients. Protected by @filelist_mutex. + */ + struct list_head filelist_internal; + /** \name Memory management */ /*@{ */ struct list_head maplist; /**< Linked list of regions */