[PATCH v2 6/8] drm: Add vmalloc BO helper
Daniel Vetter
daniel at ffwll.ch
Tue Oct 17 12:51:08 UTC 2017
On Sun, Oct 15, 2017 at 06:30:40PM +0200, Noralf Trønnes wrote:
> Add vmalloc buffer object helper that can be useful for modesetting
> drivers, particularly the framebuffer flushing kind.
>
> Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
Why can't we extend the shmem stuff to provide a simple vmalloc helper?
Doing a new flavour of gem for every special use-case seems like not a
good idea ...
This could then also be used by stuff like udl, with fewer changes.
-Daniel
> ---
> Documentation/gpu/drm-kms-helpers.rst | 12 ++
> drivers/gpu/drm/Kconfig | 7 +
> drivers/gpu/drm/Makefile | 1 +
> drivers/gpu/drm/drm_vmalloc_bo_helper.c | 305 ++++++++++++++++++++++++++++++++
> include/drm/drm_vmalloc_bo_helper.h | 88 +++++++++
> 5 files changed, 413 insertions(+)
> create mode 100644 drivers/gpu/drm/drm_vmalloc_bo_helper.c
> create mode 100644 include/drm/drm_vmalloc_bo_helper.h
>
> diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
> index 13dd237418cc..fd1ca10f6611 100644
> --- a/Documentation/gpu/drm-kms-helpers.rst
> +++ b/Documentation/gpu/drm-kms-helpers.rst
> @@ -305,3 +305,15 @@ Framebuffer GEM Helper Reference
>
> .. kernel-doc:: drivers/gpu/drm/drm_gem_framebuffer_helper.c
> :export:
> +
> +vmalloc buffer object helper
> +============================
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_vmalloc_bo_helper.c
> + :doc: overview
> +
> +.. kernel-doc:: include/drm/drm_vmalloc_bo_helper.h
> + :internal:
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_vmalloc_bo_helper.c
> + :export:
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 4d9f21831741..5d580440a259 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -145,6 +145,13 @@ config DRM_KMS_CMA_HELPER
> help
> Choose this if you need the KMS CMA helper functions
>
> +config DRM_VMALLOC_BO_HELPER
> + bool
> + depends on DRM
> + select DRM_KMS_HELPER
> + help
> + Choose this if you need the vmalloc buffer object helper functions
> +
> config DRM_VM
> bool
> depends on DRM && MMU
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index a3fdc5a68dff..ed3eafa97a69 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -39,6 +39,7 @@ drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
> drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
> drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
> drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
> +drm_kms_helper-$(CONFIG_DRM_VMALLOC_BO_HELPER) += drm_vmalloc_bo_helper.o
> drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
>
> obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
> diff --git a/drivers/gpu/drm/drm_vmalloc_bo_helper.c b/drivers/gpu/drm/drm_vmalloc_bo_helper.c
> new file mode 100644
> index 000000000000..4015b9d1d671
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_vmalloc_bo_helper.c
> @@ -0,0 +1,305 @@
> +/*
> + * DRM vmalloc buffer object helper functions
> + *
> + * Copyright (C) 2017 Noralf Trønnes
> + *
> + * 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/dma-buf.h>
> +#include <linux/export.h>
> +#include <linux/slab.h>
> +#include <linux/vmalloc.h>
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_fb_helper.h>
> +#include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_vmalloc_bo_helper.h>
> +
> +/**
> + * DOC: overview
> + *
> + * This helper provides a simple GEM based buffer object with buffers allocated
> + * using vmalloc(). This is useful for modesetting drivers that do framebuffer
> + * flushing. It supports dumb buffers and PRIME import which can be setup using
> + * the DEFINE_DRM_VMALLOC_BO_FOPS() and DRM_VMALLOC_BO_DRIVER_OPS() macros.
> + *
> + * fbdev emulation can be setup using the drm_vmalloc_bo_fbdev_probe() function.
> + */
> +
> +static struct drm_vmalloc_bo *
> +drm_vmalloc_bo_create(struct drm_device *dev, size_t size, bool backing)
> +{
> + struct drm_vmalloc_bo *bo;
> + int ret;
> +
> + size = PAGE_ALIGN(size);
> +
> + bo = kzalloc(sizeof(*bo), GFP_KERNEL);
> + if (!bo)
> + return ERR_PTR(-ENOMEM);
> +
> + if (backing) {
> + bo->vaddr = vmalloc_user(size);
> + if (!bo->vaddr) {
> + ret = -ENOMEM;
> + goto error_free;
> + }
> + }
> +
> + drm_gem_private_object_init(dev, &bo->base, size);
> +
> + return bo;
> +
> +error_free:
> + kfree(bo);
> +
> + return ERR_PTR(ret);
> +}
> +
> +/**
> + * drm_vmalloc_bo_free_object() - Free resources associated with a vmalloc BO
> + * object
> + * @obj: GEM object to free
> + *
> + * This function frees the backing memory of the vmalloc BO object, cleans up
> + * the GEM object state and frees the memory used to store the object itself.
> + * Drivers using the vmalloc BO helpers should set this as their
> + * &drm_driver.gem_free_object callback.
> + */
> +void drm_vmalloc_bo_free_object(struct drm_gem_object *obj)
> +{
> + struct drm_vmalloc_bo *bo = to_drm_vmalloc_bo(obj);
> +
> + if (obj->import_attach)
> + dma_buf_vunmap(obj->import_attach->dmabuf, bo->vaddr);
> + else
> + vfree(bo->vaddr);
> +
> + drm_gem_object_release(obj);
> + kfree(bo);
> +}
> +EXPORT_SYMBOL(drm_vmalloc_bo_free_object);
> +
> +/**
> + * drm_vmalloc_bo_dumb_create() - Create a dumb vmalloc BO
> + * @file: DRM file structure to create the dumb buffer for
> + * @dev: DRM device
> + * @args: IOCTL data
> + *
> + * This function computes the pitch of the dumb buffer and rounds it up to an
> + * integer number of bytes per pixel. Drivers for hardware that doesn't have
> + * any additional restrictions on the pitch can directly use this function as
> + * their &drm_driver.dumb_create callback.
> + *
> + * For hardware with additional restrictions, drivers can adjust the fields
> + * set up by userspace before calling into this function. Also
> + * &drm_mode_create_dumb.pitch and &drm_mode_create_dumb.size can be set.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_vmalloc_bo_dumb_create(struct drm_file *file, struct drm_device *dev,
> + struct drm_mode_create_dumb *args)
> +{
> + struct drm_vmalloc_bo *bo;
> + int ret;
> +
> + if (!args->pitch)
> + args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
> + else
> + args->pitch = max(args->pitch,
> + DIV_ROUND_UP(args->width * args->bpp, 8));
> + if (!args->size)
> + args->size = args->pitch * args->height;
> + else
> + args->size = max_t(typeof(args->size), args->size,
> + args->pitch * args->height);
> +
> + bo = drm_vmalloc_bo_create(dev, args->size, true);
> + if (IS_ERR(bo))
> + return PTR_ERR(bo);
> +
> + ret = drm_gem_handle_create(file, &bo->base, &args->handle);
> + /* drop reference from allocate - handle holds it now. */
> + drm_gem_object_put_unlocked(&bo->base);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_vmalloc_bo_dumb_create);
> +
> +const struct vm_operations_struct drm_vmalloc_bo_vm_ops = {
> + .open = drm_gem_vm_open,
> + .close = drm_gem_vm_close,
> +};
> +EXPORT_SYMBOL_GPL(drm_vmalloc_bo_vm_ops);
> +
> +/**
> + * drm_vmalloc_bo_mmap() - Memory-map a vmalloc BO
> + * @filp: File object
> + * @vma: VMA for the area to be mapped
> + *
> + * This function implements an augmented version of the GEM DRM file mmap
> + * operation for vmalloc buffer objects. Drivers should use this function as
> + * their ->mmap handler in the DRM device file's file_operations structure.
> + *
> + * Instead of directly referencing this function, drivers should use the
> + * DEFINE_DRM_VMALLOC_BO_FOPS() macro.
> + *
> + * Returns:
> + * Zero on success or a negative error code on failure.
> + */
> +int drm_vmalloc_bo_mmap(struct file *filp, struct vm_area_struct *vma)
> +{
> + struct drm_vmalloc_bo *bo;
> + int ret;
> +
> + ret = drm_gem_mmap(filp, vma);
> + if (ret)
> + return ret;
> +
> + /* Set by drm_gem_mmap() */
> + vma->vm_flags &= ~VM_IO;
> + vma->vm_flags &= ~VM_PFNMAP;
> +
> + bo = to_drm_vmalloc_bo(vma->vm_private_data);
> +
> + return remap_vmalloc_range(vma, bo->vaddr, 0);
> +}
> +EXPORT_SYMBOL(drm_vmalloc_bo_mmap);
> +
> +/**
> + * drm_vmalloc_bo_prime_import_sg_table() - Produce a vmalloc BO from a dma-buf
> + * @dev: DRM device to import into
> + * @attach: dmabuf attachment
> + * @sgt: Scatter/gather table of pinned pages
> + *
> + * This function creates a vmalloc buffer object using the virtual address on
> + * the dma-buf exported by another driver. Drivers using the vmalloc BO helpers
> + * should set this as their &drm_driver.gem_prime_import_sg_table callback.
> + *
> + * Returns:
> + * A pointer to a newly created GEM object or an ERR_PTR-encoded negative
> + * error code on failure.
> + */
> +struct drm_gem_object *
> +drm_vmalloc_bo_prime_import_sg_table(struct drm_device *dev,
> + struct dma_buf_attachment *attach,
> + struct sg_table *sgt)
> +{
> + struct drm_vmalloc_bo *bo;
> + void *vaddr;
> +
> + vaddr = dma_buf_vmap(attach->dmabuf);
> + if (!vaddr) {
> + DRM_ERROR("Failed to vmap PRIME buffer\n");
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + bo = drm_vmalloc_bo_create(dev, attach->dmabuf->size, false);
> + if (IS_ERR(bo)) {
> + dma_buf_vunmap(attach->dmabuf, vaddr);
> + return ERR_CAST(bo);
> + }
> +
> + bo->vaddr = vaddr;
> +
> + DRM_DEBUG_PRIME("size = %zu\n", attach->dmabuf->size);
> +
> + return &bo->base;
> +}
> +EXPORT_SYMBOL(drm_vmalloc_bo_prime_import_sg_table);
> +
> +static struct fb_ops drm_vmalloc_bo_fbdev_ops = {
> + .owner = THIS_MODULE,
> + DRM_FB_HELPER_DEFAULT_OPS,
> + .fb_read = drm_fb_helper_sys_read,
> + .fb_write = drm_fb_helper_sys_write,
> + .fb_fillrect = drm_fb_helper_sys_fillrect,
> + .fb_copyarea = drm_fb_helper_sys_copyarea,
> + .fb_imageblit = drm_fb_helper_sys_imageblit,
> +};
> +
> +/**
> + * drm_vmalloc_bo_fbdev_probe - fbdev emulation \.fb_probe helper
> + * @fb_helper: fbdev emulation helper structure
> + * @sizes: Describes fbdev size and scanout surface size
> + * @fb_funcs: DRM framebuffer functions
> + *
> + * This function can be used in the &drm_fb_helper_funcs.fb_probe callback to
> + * setup fbdev emulation. If @fb_funcs->dirty is set, fbdev deferred I/O is
> + * initialized. drm_fb_helper_simple_init() can be used to initialize the fbdev
> + * emulation.
> + *
> + * Returns:
> + * Zero on success, negative error code on failure.
> + */
> +int drm_vmalloc_bo_fbdev_probe(struct drm_fb_helper *fb_helper,
> + struct drm_fb_helper_surface_size *sizes,
> + const struct drm_framebuffer_funcs *fb_funcs)
> +{
> + struct drm_device *dev = fb_helper->dev;
> + struct drm_framebuffer *fb;
> + struct drm_vmalloc_bo *bo;
> + struct fb_info *fbi;
> + size_t size;
> + int ret;
> +
> + DRM_DEBUG_KMS("surface width(%d), height(%d) and bpp(%d)\n",
> + sizes->surface_width, sizes->surface_height,
> + sizes->surface_bpp);
> +
> + size = sizes->surface_width * sizes->surface_height *
> + DIV_ROUND_UP(sizes->surface_bpp, 8);
> +
> + bo = drm_vmalloc_bo_create(dev, size, true);
> + if (IS_ERR(bo))
> + return -ENOMEM;
> +
> + fb = drm_gem_fbdev_fb_create(dev, sizes, 0, &bo->base, fb_funcs);
> + if (IS_ERR(fb)) {
> + dev_err(dev->dev, "Failed to allocate DRM framebuffer.\n");
> + ret = PTR_ERR(fb);
> + goto err_bo_free;
> + }
> +
> + fb_helper->fb = fb;
> +
> + fbi = drm_fb_helper_alloc_fbi(fb_helper);
> + if (IS_ERR(fbi)) {
> + ret = PTR_ERR(fbi);
> + goto err_fb_free;
> + }
> +
> + fbi->par = fb_helper;
> + fbi->flags = FBINFO_VIRTFB;
> + fbi->fbops = &drm_vmalloc_bo_fbdev_ops;
> +
> + drm_fb_helper_fill_fix(fbi, fb->pitches[0], fb->format->depth);
> + drm_fb_helper_fill_var(fbi, fb_helper, sizes->fb_width, sizes->fb_height);
> +
> + fbi->screen_base = bo->vaddr;
> + fbi->screen_size = size;
> + fbi->fix.smem_len = size;
> +
> + if (fb_funcs->dirty) {
> + ret = drm_fb_helper_defio_init(fb_helper);
> + if (ret)
> + goto err_fb_info_destroy;
> + }
> +
> + return 0;
> +
> +err_fb_info_destroy:
> + drm_fb_helper_fini(fb_helper);
> +err_fb_free:
> + drm_framebuffer_remove(fb);
> +err_bo_free:
> + drm_gem_object_put_unlocked(&bo->base);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_vmalloc_bo_fbdev_probe);
> diff --git a/include/drm/drm_vmalloc_bo_helper.h b/include/drm/drm_vmalloc_bo_helper.h
> new file mode 100644
> index 000000000000..0df3d15e2e4a
> --- /dev/null
> +++ b/include/drm/drm_vmalloc_bo_helper.h
> @@ -0,0 +1,88 @@
> +#ifndef __DRM_VMALLOC_BO_HELPER_H__
> +#define __DRM_VMALLOC_BO_HELPER_H__
> +
> +#include <drm/drmP.h>
> +#include <drm/drm_gem.h>
> +
> +struct drm_fb_helper_surface_size;
> +
> +/**
> + * struct drm_vmalloc_bo - vmalloc buffer object
> + */
> +struct drm_vmalloc_bo {
> + /**
> + * @base:
> + *
> + * Base GEM object.
> + */
> + struct drm_gem_object base;
> +
> + /**
> + * @vaddr:
> + *
> + * Kernel virtual address of the buffer.
> + */
> + void *vaddr;
> +};
> +
> +static inline struct drm_vmalloc_bo *
> +to_drm_vmalloc_bo(struct drm_gem_object *obj)
> +{
> + return container_of(obj, struct drm_vmalloc_bo, base);
> +}
> +
> +static inline void *drm_vmalloc_bo_fb_vaddr(struct drm_framebuffer *fb)
> +{
> + return to_drm_vmalloc_bo(fb->obj[0])->vaddr;
> +}
> +
> +void drm_vmalloc_bo_free_object(struct drm_gem_object *obj);
> +int drm_vmalloc_bo_dumb_create(struct drm_file *file, struct drm_device *dev,
> + struct drm_mode_create_dumb *args);
> +int drm_vmalloc_bo_mmap(struct file *filp, struct vm_area_struct *vma);
> +struct drm_gem_object *
> +drm_vmalloc_bo_prime_import_sg_table(struct drm_device *dev,
> + struct dma_buf_attachment *attach,
> + struct sg_table *sgt);
> +
> +int drm_vmalloc_bo_fbdev_probe(struct drm_fb_helper *fb_helper,
> + struct drm_fb_helper_surface_size *sizes,
> + const struct drm_framebuffer_funcs *fb_funcs);
> +
> +/**
> + * DEFINE_DRM_VMALLOC_BO_FOPS() - Macro to generate file operations for drivers
> + * @name: Name for the generated structure
> + *
> + * This macro autogenerates a suitable &struct file_operations which can be
> + * assigned to &drm_driver.fops for vmalloc BO drivers.
> + */
> +#define DEFINE_DRM_VMALLOC_BO_FOPS(name) \
> + static const struct file_operations name = {\
> + .owner = THIS_MODULE,\
> + .open = drm_open,\
> + .release = drm_release,\
> + .unlocked_ioctl = drm_ioctl,\
> + .compat_ioctl = drm_compat_ioctl,\
> + .poll = drm_poll,\
> + .read = drm_read,\
> + .llseek = noop_llseek,\
> + .mmap = drm_vmalloc_bo_mmap,\
> + }
> +
> +extern const struct vm_operations_struct drm_vmalloc_bo_vm_ops;
> +
> +/**
> + * DRM_VMALLOC_BO_DRIVER_OPS - Default GEM and PRIME operations
> + *
> + * This macro provides a shortcut for setting the GEM and PRIME operations in
> + * the &drm_driver structure for vmalloc BO drivers.
> + */
> +#define DRM_VMALLOC_BO_DRIVER_OPS \
> + .gem_free_object = drm_vmalloc_bo_free_object, \
> + .gem_vm_ops = &drm_vmalloc_bo_vm_ops, \
> + .prime_fd_to_handle = drm_gem_prime_fd_to_handle, \
> + .gem_prime_import = drm_gem_prime_import, \
> + .gem_prime_import_sg_table = drm_vmalloc_bo_prime_import_sg_table, \
> + .dumb_create = drm_vmalloc_bo_dumb_create
> +
> +#endif /* __DRM_VMALLOC_BO_HELPER_H__ */
> --
> 2.14.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
More information about the dri-devel
mailing list