Re: [PATCH v3 1/3] drm: add SimpleDRM driver

[Daniel Vetter]

On Sun, Aug 14, 2016 at 06:52:04PM +0200, Noralf Trønnes wrote:
> The SimpleDRM driver binds to simple-framebuffer devices and provides a
> DRM/KMS API. It provides only a single CRTC+encoder+connector combination
> plus one initial mode.
> 
> Userspace can create dumb-buffers which can be blit into the real
> framebuffer similar to UDL. No access to the real framebuffer is allowed
> (compared to earlier version of this driver) to avoid security issues.
> Furthermore, this way we can support arbitrary modes as long as we have a
> conversion-helper.
> 
> The driver was originally written by David Herrmann in 2014.
> My main contribution is to make use of drm_simple_kms_helper and
> rework the probe path to avoid use of the deprecated drm_platform_init()
> and drm_driver.{load,unload}().
> Additions have also been made for later changes to the Device Tree binding
> document, like support for clocks, regulators and having the node under
> /chosen. This code was lifted verbatim from simplefb.c.
> 
> Cc: dh.herrmann@xxxxxxxxx
> Cc: libv@xxxxxxxxx
> Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>

Overall looks nice, but I think we can try to get rid of a bit more
boilerplate still. Comments below.
-Daniel

> ---
> 
> Changes from version 2:
> - Remove superfluos module.h includes
> - Move includes from header to source files
> - Set plane.fb before flushing in pipe update, or else the previous one
>   gets flushed
> - Added check for vblank event in sdrm_display_pipe_update()
> 
> Changes from version 1:
> - Move platform_set_drvdata() before drm_dev_register()
> - Remove drm_legacy_mmap() call.
> - Set mode_config.{min,max}_{width,height} to the actual dimensions
>   of the native framebuffer
> - Remove plane positioning since it won't work with the simple display pipe,
>   meaning sdrm_display_pipe_check() isn't necessary either
> - Support the additions to the Device Tree binding document, including
>   clocks, regulators and having the node under /chosen
> 
> Changes from previous version:
> - Remove FB_SIMPLE=n dependency to avoid kconfig recursive error
> - Changed module name to match kconfig help text: sdrm -> simpledrm
> - Use drm_simple_display_pipe
> - Replace deprecated drm_platform_init()
> - sdrm_dumb_create(): drm_gem_object_unreference() -> *_unlocked()
> - sdrm_dumb_map_offset(): drm_gem_object_lookup() remove drm_device parameter
> - sdrm_drm_mmap() changes:
>   Remove struct_mutex locking
>   Add drm_vma_offset_{lock,unlock}_lookup()
>   drm_mmap() -> drm_legacy_mmap()
> - dma_buf_begin_cpu_access() doesn't require start and length anymore
> - Use drm_cvt_mode() instead of open coding a mode
> - Fix format conversion. In the intermediate step, store the 8/6/5 bit color
>   value in the upper part of the 16-bit color variable, not the lower.
> - Support clips == NULL in sdrm_dirty()
> - Set mode_config.preferred_depth
> - Attach mode_config.dirty_info_property to connector

dirty_info is gone now in drm-misc.

> 
>  drivers/gpu/drm/Kconfig                      |   2 +
>  drivers/gpu/drm/Makefile                     |   1 +
>  drivers/gpu/drm/simpledrm/Kconfig            |  19 +
>  drivers/gpu/drm/simpledrm/Makefile           |   4 +
>  drivers/gpu/drm/simpledrm/simpledrm.h        |  90 +++++
>  drivers/gpu/drm/simpledrm/simpledrm_damage.c | 302 +++++++++++++++
>  drivers/gpu/drm/simpledrm/simpledrm_drv.c    | 539 +++++++++++++++++++++++++++
>  drivers/gpu/drm/simpledrm/simpledrm_gem.c    | 274 ++++++++++++++
>  drivers/gpu/drm/simpledrm/simpledrm_kms.c    | 258 +++++++++++++
>  9 files changed, 1489 insertions(+)
>  create mode 100644 drivers/gpu/drm/simpledrm/Kconfig
>  create mode 100644 drivers/gpu/drm/simpledrm/Makefile
>  create mode 100644 drivers/gpu/drm/simpledrm/simpledrm.h
>  create mode 100644 drivers/gpu/drm/simpledrm/simpledrm_damage.c
>  create mode 100644 drivers/gpu/drm/simpledrm/simpledrm_drv.c
>  create mode 100644 drivers/gpu/drm/simpledrm/simpledrm_gem.c
>  create mode 100644 drivers/gpu/drm/simpledrm/simpledrm_kms.c
> 
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index fc35731..a54cc8d 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -290,3 +290,5 @@ source "drivers/gpu/drm/arc/Kconfig"
>  source "drivers/gpu/drm/hisilicon/Kconfig"
> 
>  source "drivers/gpu/drm/mediatek/Kconfig"
> +
> +source "drivers/gpu/drm/simpledrm/Kconfig"
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index e3dba6f..eba32ad 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -83,3 +83,4 @@ obj-$(CONFIG_DRM_FSL_DCU) += fsl-dcu/
>  obj-$(CONFIG_DRM_ETNAVIV) += etnaviv/
>  obj-$(CONFIG_DRM_ARCPGU)+= arc/
>  obj-y			+= hisilicon/
> +obj-$(CONFIG_DRM_SIMPLEDRM) += simpledrm/
> diff --git a/drivers/gpu/drm/simpledrm/Kconfig b/drivers/gpu/drm/simpledrm/Kconfig
> new file mode 100644
> index 0000000..f45b25d
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/Kconfig
> @@ -0,0 +1,19 @@
> +config DRM_SIMPLEDRM
> +	tristate "Simple firmware framebuffer DRM driver"
> +	depends on DRM
> +	select DRM_KMS_HELPER
> +	help
> +	  SimpleDRM can run on all systems with pre-initialized graphics
> +	  hardware. It uses a framebuffer that was initialized during
> +	  firmware boot. No page-flipping, modesetting or other advanced
> +	  features are available. However, other DRM drivers can be loaded
> +	  later and take over from SimpleDRM if they provide real hardware
> +	  support.
> +
> +	  SimpleDRM supports "simple-framebuffer" DeviceTree objects and
> +	  compatible platform framebuffers.
> +
> +	  If unsure, say Y.
> +
> +	  To compile this driver as a module, choose M here: the
> +	  module will be called simpledrm.
> diff --git a/drivers/gpu/drm/simpledrm/Makefile b/drivers/gpu/drm/simpledrm/Makefile
> new file mode 100644
> index 0000000..f6a62dc
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/Makefile
> @@ -0,0 +1,4 @@
> +simpledrm-y :=	simpledrm_drv.o simpledrm_kms.o simpledrm_gem.o \
> +		simpledrm_damage.o
> +
> +obj-$(CONFIG_DRM_SIMPLEDRM) := simpledrm.o
> diff --git a/drivers/gpu/drm/simpledrm/simpledrm.h b/drivers/gpu/drm/simpledrm/simpledrm.h
> new file mode 100644
> index 0000000..481acc2
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/simpledrm.h
> @@ -0,0 +1,90 @@
> +/*
> + * SimpleDRM firmware framebuffer driver
> + * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@xxxxxxxxx>
> + *
> + * 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.
> + */
> +
> +#ifndef SDRM_DRV_H
> +#define SDRM_DRV_H
> +
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_gem.h>
> +#include <drm/drm_simple_kms_helper.h>
> +
> +struct simplefb_format;
> +struct regulator;
> +struct fb_info;
> +struct clk;
> +
> +struct sdrm_device {
> +	struct drm_device *ddev;
> +	struct drm_simple_display_pipe pipe;
> +	struct drm_connector conn;
> +
> +	/* framebuffer information */
> +	const struct simplefb_format *fb_sformat;
> +	u32 fb_format;
> +	u32 fb_width;
> +	u32 fb_height;
> +	u32 fb_stride;
> +	u32 fb_bpp;
> +	unsigned long fb_base;
> +	unsigned long fb_size;
> +	void *fb_map;
> +
> +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> +	unsigned int clk_count;
> +	struct clk **clks;
> +#endif
> +#if defined CONFIG_OF && defined CONFIG_REGULATOR
> +	u32 regulator_count;
> +	struct regulator **regulators;
> +#endif
> +};
> +
> +int sdrm_drm_modeset_init(struct sdrm_device *sdrm);
> +int sdrm_drm_mmap(struct file *filp, struct vm_area_struct *vma);
> +
> +int sdrm_dirty(struct drm_framebuffer *fb,
> +	       struct drm_file *file,
> +	       unsigned int flags, unsigned int color,
> +	       struct drm_clip_rect *clips,
> +	       unsigned int num_clips);
> +int sdrm_dirty_all_locked(struct sdrm_device *sdrm);
> +int sdrm_dirty_all_unlocked(struct sdrm_device *sdrm);
> +
> +struct sdrm_gem_object {
> +	struct drm_gem_object base;
> +	struct sg_table *sg;
> +	struct page **pages;
> +	void *vmapping;
> +};
> +
> +#define to_sdrm_bo(x) container_of(x, struct sdrm_gem_object, base)
> +
> +struct sdrm_gem_object *sdrm_gem_alloc_object(struct drm_device *ddev,
> +					      size_t size);
> +struct drm_gem_object *sdrm_gem_prime_import(struct drm_device *ddev,
> +					     struct dma_buf *dma_buf);
> +void sdrm_gem_free_object(struct drm_gem_object *obj);
> +int sdrm_gem_get_pages(struct sdrm_gem_object *obj);
> +
> +int sdrm_dumb_create(struct drm_file *file_priv, struct drm_device *ddev,
> +		     struct drm_mode_create_dumb *arg);
> +int sdrm_dumb_destroy(struct drm_file *file_priv, struct drm_device *ddev,
> +		      uint32_t handle);
> +int sdrm_dumb_map_offset(struct drm_file *file_priv, struct drm_device *ddev,
> +			 uint32_t handle, uint64_t *offset);
> +
> +struct sdrm_framebuffer {
> +	struct drm_framebuffer base;
> +	struct sdrm_gem_object *obj;
> +};
> +
> +#define to_sdrm_fb(x) container_of(x, struct sdrm_framebuffer, base)
> +
> +#endif /* SDRM_DRV_H */
> diff --git a/drivers/gpu/drm/simpledrm/simpledrm_damage.c b/drivers/gpu/drm/simpledrm/simpledrm_damage.c
> new file mode 100644
> index 0000000..ee3d465
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/simpledrm_damage.c
> @@ -0,0 +1,302 @@
> +/*
> + * SimpleDRM firmware framebuffer driver
> + * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@xxxxxxxxx>
> + *
> + * 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 <asm/unaligned.h>
> +#include <drm/drmP.h>
> +#include <drm/drm_crtc.h>
> +#include <linux/dma-buf.h>
> +#include <linux/kernel.h>
> +#include <linux/string.h>
> +
> +#include "simpledrm.h"
> +
> +static inline void sdrm_put(u8 *dst, u32 four_cc, u16 r, u16 g, u16 b)
> +{
> +	switch (four_cc) {
> +	case DRM_FORMAT_RGB565:
> +		r >>= 11;
> +		g >>= 10;
> +		b >>= 11;
> +		put_unaligned((u16)((r << 11) | (g << 5) | b), (u16 *)dst);
> +		break;
> +	case DRM_FORMAT_XRGB1555:
> +	case DRM_FORMAT_ARGB1555:
> +		r >>= 11;
> +		g >>= 11;
> +		b >>= 11;
> +		put_unaligned((u16)((r << 10) | (g << 5) | b), (u16 *)dst);
> +		break;
> +	case DRM_FORMAT_RGB888:
> +		r >>= 8;
> +		g >>= 8;
> +		b >>= 8;
> +#ifdef __LITTLE_ENDIAN
> +		dst[2] = r;
> +		dst[1] = g;
> +		dst[0] = b;
> +#elif defined(__BIG_ENDIAN)
> +		dst[0] = r;
> +		dst[1] = g;
> +		dst[2] = b;
> +#endif
> +		break;
> +	case DRM_FORMAT_XRGB8888:
> +	case DRM_FORMAT_ARGB8888:
> +		r >>= 8;
> +		g >>= 8;
> +		b >>= 8;
> +		put_unaligned((u32)((r << 16) | (g << 8) | b), (u32 *)dst);
> +		break;
> +	case DRM_FORMAT_ABGR8888:
> +		r >>= 8;
> +		g >>= 8;
> +		b >>= 8;
> +		put_unaligned((u32)((b << 16) | (g << 8) | r), (u32 *)dst);
> +		break;
> +	case DRM_FORMAT_XRGB2101010:
> +	case DRM_FORMAT_ARGB2101010:
> +		r >>= 4;
> +		g >>= 4;
> +		b >>= 4;
> +		put_unaligned((u32)((r << 20) | (g << 10) | b), (u32 *)dst);
> +		break;
> +	}
> +}
> +
> +static void sdrm_blit_from_xrgb8888(const u8 *src, u32 src_stride, u32 src_bpp,
> +				    u8 *dst, u32 dst_stride, u32 dst_bpp,
> +				    u32 dst_four_cc, u32 width, u32 height)
> +{
> +	u32 val, i;
> +
> +	while (height--) {
> +		for (i = 0; i < width; ++i) {
> +			val = get_unaligned((const u32 *)&src[i * src_bpp]);
> +			sdrm_put(&dst[i * dst_bpp], dst_four_cc,
> +				 (val & 0x00ff0000U) >> 8,
> +				 (val & 0x0000ff00U),
> +				 (val & 0x000000ffU) << 8);
> +		}
> +
> +		src += src_stride;
> +		dst += dst_stride;
> +	}
> +}
> +
> +static void sdrm_blit_from_rgb565(const u8 *src, u32 src_stride, u32 src_bpp,
> +				  u8 *dst, u32 dst_stride, u32 dst_bpp,
> +				  u32 dst_four_cc, u32 width, u32 height)
> +{
> +	u32 val, i;
> +
> +	while (height--) {
> +		for (i = 0; i < width; ++i) {
> +			val = get_unaligned((const u16 *)&src[i * src_bpp]);
> +			sdrm_put(&dst[i * dst_bpp], dst_four_cc,
> +				 (val & 0xf800),
> +				 (val & 0x07e0) << 5,
> +				 (val & 0x001f) << 11);
> +		}
> +
> +		src += src_stride;
> +		dst += dst_stride;
> +	}
> +}
> +
> +static void sdrm_blit_lines(const u8 *src, u32 src_stride,
> +			    u8 *dst, u32 dst_stride,
> +			    u32 bpp, u32 width, u32 height)
> +{
> +	u32 len;
> +
> +	len = width * bpp;
> +
> +	while (height--) {
> +		memcpy(dst, src, len);
> +		src += src_stride;
> +		dst += dst_stride;
> +	}
> +}
> +
> +static void sdrm_blit(struct sdrm_framebuffer *sfb, u32 x, u32 y,
> +		      u32 width, u32 height)
> +{
> +	struct drm_framebuffer *fb = &sfb->base;
> +	struct drm_device *ddev = fb->dev;
> +	struct sdrm_device *sdrm = ddev->dev_private;
> +	u32 src_bpp, dst_bpp, x2, y2;
> +	u8 *src, *dst;
> +
> +	/* already unmapped; ongoing handover? */
> +	if (!sdrm->fb_map)
> +		return;
> +
> +	/* empty dirty-region, nothing to do */
> +	if (!width || !height)
> +		return;
> +	if (x >= fb->width || y >= fb->height)
> +		return;
> +
> +	/* sanity checks */
> +	if (x + width < x)
> +		width = fb->width - x;
> +	if (y + height < y)
> +		height = fb->height - y;
> +
> +	/* get intersection of dirty region and scan-out region */
> +	x2 = min(x + width, sdrm->fb_width);
> +	y2 = min(y + height, sdrm->fb_height);
> +	if (x2 <= x || y2 <= y)
> +		return;
> +	width = x2 - x;
> +	height = y2 - y;
> +
> +	/* get buffer offsets */
> +	src = sfb->obj->vmapping;
> +	dst = sdrm->fb_map;
> +
> +	/* bo is guaranteed to be big enough; size checks not needed */
> +	src_bpp = (fb->bits_per_pixel + 7) / 8;
> +	src += fb->offsets[0] + y * fb->pitches[0] + x * src_bpp;
> +
> +	dst_bpp = (sdrm->fb_bpp + 7) / 8;
> +	dst += y * sdrm->fb_stride + x * dst_bpp;
> +
> +	/* if formats are identical, do a line-by-line copy.. */
> +	if (fb->pixel_format == sdrm->fb_format) {
> +		sdrm_blit_lines(src, fb->pitches[0],
> +				dst, sdrm->fb_stride,
> +				src_bpp, width, height);
> +		return;
> +	}
> +
> +	/* ..otherwise call slow blit-function */
> +	switch (fb->pixel_format) {
> +	case DRM_FORMAT_ARGB8888:
> +		/* fallthrough */
> +	case DRM_FORMAT_XRGB8888:
> +		sdrm_blit_from_xrgb8888(src, fb->pitches[0], src_bpp,
> +					dst, sdrm->fb_stride, dst_bpp,
> +					sdrm->fb_format, width, height);
> +		break;
> +	case DRM_FORMAT_RGB565:
> +		sdrm_blit_from_rgb565(src, fb->pitches[0], src_bpp,
> +				      dst, sdrm->fb_stride, dst_bpp,
> +				      sdrm->fb_format, width, height);
> +		break;
> +	}
> +}
> +
> +static int sdrm_begin_access(struct sdrm_framebuffer *sfb)
> +{
> +	int r;
> +
> +	r = sdrm_gem_get_pages(sfb->obj);
> +	if (r)
> +		return r;
> +
> +	if (!sfb->obj->base.import_attach)
> +		return 0;
> +
> +	return dma_buf_begin_cpu_access(sfb->obj->base.import_attach->dmabuf,
> +					DMA_FROM_DEVICE);
> +}
> +
> +static void sdrm_end_access(struct sdrm_framebuffer *sfb)
> +{
> +	if (!sfb->obj->base.import_attach)
> +		return;
> +
> +	dma_buf_end_cpu_access(sfb->obj->base.import_attach->dmabuf,
> +			       DMA_FROM_DEVICE);
> +}
> +
> +int sdrm_dirty(struct drm_framebuffer *fb,
> +	       struct drm_file *file,
> +	       unsigned int flags, unsigned int color,
> +	       struct drm_clip_rect *clips,
> +	       unsigned int num_clips)
> +{
> +	struct sdrm_framebuffer *sfb = to_sdrm_fb(fb);
> +	struct drm_device *ddev = fb->dev;
> +	struct sdrm_device *sdrm = ddev->dev_private;
> +	struct drm_clip_rect full_clip;
> +	unsigned int i;
> +	int r;
> +
> +	if (!clips || !num_clips) {
> +		full_clip.x1 = 0;
> +		full_clip.x2 = fb->width;
> +		full_clip.y1 = 0;
> +		full_clip.y2 = fb->height;
> +		clips = &full_clip;
> +		num_clips = 1;
> +	}
> +
> +	drm_modeset_lock_all(ddev);
> +
> +	if (sdrm->pipe.plane.fb != fb) {
> +		r = 0;
> +		goto unlock;
> +	}
> +
> +	r = sdrm_begin_access(sfb);
> +	if (r)
> +		goto unlock;
> +
> +	for (i = 0; i < num_clips; i++) {
> +		if (clips[i].x2 <= clips[i].x1 ||
> +		    clips[i].y2 <= clips[i].y1)
> +			continue;
> +
> +		sdrm_blit(sfb, clips[i].x1, clips[i].y1,
> +			  clips[i].x2 - clips[i].x1,
> +			  clips[i].y2 - clips[i].y1);
> +	}
> +
> +	sdrm_end_access(sfb);
> +
> +unlock:
> +	drm_modeset_unlock_all(ddev);
> +	return 0;
> +}
> +
> +int sdrm_dirty_all_locked(struct sdrm_device *sdrm)
> +{
> +	struct drm_framebuffer *fb;
> +	struct sdrm_framebuffer *sfb;
> +	int r;
> +
> +	fb = sdrm->pipe.plane.fb;
> +	if (!fb)
> +		return 0;
> +
> +	sfb = to_sdrm_fb(fb);
> +	r = sdrm_begin_access(sfb);
> +	if (r)
> +		return r;
> +
> +	sdrm_blit(sfb, 0, 0, fb->width, fb->height);
> +
> +	sdrm_end_access(sfb);
> +
> +	return 0;
> +}
> +
> +int sdrm_dirty_all_unlocked(struct sdrm_device *sdrm)
> +{
> +	int r;
> +
> +	drm_modeset_lock_all(sdrm->ddev);
> +	r = sdrm_dirty_all_locked(sdrm);
> +	drm_modeset_unlock_all(sdrm->ddev);
> +
> +	return r;
> +}

Seems unused?

> diff --git a/drivers/gpu/drm/simpledrm/simpledrm_drv.c b/drivers/gpu/drm/simpledrm/simpledrm_drv.c
> new file mode 100644
> index 0000000..e5b6f75
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/simpledrm_drv.c
> @@ -0,0 +1,539 @@
> +/*
> + * SimpleDRM firmware framebuffer driver
> + * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@xxxxxxxxx>
> + *
> + * 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 <drm/drmP.h>
> +#include <linux/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/errno.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/mm.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_data/simplefb.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/string.h>
> +
> +#include "simpledrm.h"
> +
> +static const struct file_operations sdrm_drm_fops = {
> +	.owner = THIS_MODULE,
> +	.open = drm_open,
> +	.mmap = sdrm_drm_mmap,
> +	.poll = drm_poll,
> +	.read = drm_read,
> +	.unlocked_ioctl = drm_ioctl,
> +	.release = drm_release,
> +#ifdef CONFIG_COMPAT
> +	.compat_ioctl = drm_compat_ioctl,
> +#endif
> +	.llseek = noop_llseek,
> +};
> +
> +static struct drm_driver sdrm_drm_driver = {
> +	.driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_PRIME |
> +			   DRIVER_ATOMIC,
> +	.fops = &sdrm_drm_fops,
> +
> +	.gem_free_object = sdrm_gem_free_object,
> +	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> +	.gem_prime_import = sdrm_gem_prime_import,
> +
> +	.dumb_create = sdrm_dumb_create,
> +	.dumb_map_offset = sdrm_dumb_map_offset,
> +	.dumb_destroy = sdrm_dumb_destroy,
> +
> +	.name = "simpledrm",
> +	.desc = "Simple firmware framebuffer DRM driver",
> +	.date = "20130601",
> +	.major = 0,
> +	.minor = 0,
> +	.patchlevel = 1,
> +};
> +
> +#if defined CONFIG_OF && defined CONFIG_COMMON_CLK
> +/*
> + * Clock handling code.
> + *
> + * Here we handle the clocks property of our "simple-framebuffer" dt node.
> + * This is necessary so that we can make sure that any clocks needed by
> + * the display engine that the bootloader set up for us (and for which it
> + * provided a simplefb dt node), stay up, for the life of the simplefb
> + * driver.
> + *
> + * When the driver unloads, we cleanly disable, and then release the clocks.
> + *
> + * We only complain about errors here, no action is taken as the most likely
> + * error can only happen due to a mismatch between the bootloader which set
> + * up simplefb, and the clock definitions in the device tree. Chances are
> + * that there are no adverse effects, and if there are, a clean teardown of
> + * the fb probe will not help us much either. So just complain and carry on,
> + * and hope that the user actually gets a working fb at the end of things.
> + */
> +static int sdrm_clocks_init(struct sdrm_device *sdrm,
> +			    struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct clk *clock;
> +	int i, ret;
> +
> +	if (dev_get_platdata(&pdev->dev) || !np)
> +		return 0;
> +
> +	sdrm->clk_count = of_clk_get_parent_count(np);
> +	if (!sdrm->clk_count)
> +		return 0;
> +
> +	sdrm->clks = kcalloc(sdrm->clk_count, sizeof(struct clk *), GFP_KERNEL);
> +	if (!sdrm->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < sdrm->clk_count; i++) {
> +		clock = of_clk_get(np, i);
> +		if (IS_ERR(clock)) {
> +			if (PTR_ERR(clock) == -EPROBE_DEFER) {
> +				while (--i >= 0) {
> +					if (sdrm->clks[i])
> +						clk_put(sdrm->clks[i]);
> +				}
> +				kfree(sdrm->clks);
> +				return -EPROBE_DEFER;
> +			}
> +			dev_err(&pdev->dev, "%s: clock %d not found: %ld\n",
> +				__func__, i, PTR_ERR(clock));
> +			continue;
> +		}
> +		sdrm->clks[i] = clock;
> +	}
> +
> +	for (i = 0; i < sdrm->clk_count; i++) {
> +		if (sdrm->clks[i]) {
> +			ret = clk_prepare_enable(sdrm->clks[i]);
> +			if (ret) {
> +				dev_err(&pdev->dev,
> +					"%s: failed to enable clock %d: %d\n",
> +					__func__, i, ret);
> +				clk_put(sdrm->clks[i]);
> +				sdrm->clks[i] = NULL;
> +			}
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static void sdrm_clocks_destroy(struct sdrm_device *sdrm)
> +{
> +	int i;
> +
> +	if (!sdrm->clks)
> +		return;
> +
> +	for (i = 0; i < sdrm->clk_count; i++) {
> +		if (sdrm->clks[i]) {
> +			clk_disable_unprepare(sdrm->clks[i]);
> +			clk_put(sdrm->clks[i]);
> +		}
> +	}
> +
> +	kfree(sdrm->clks);
> +}
> +#else
> +static int sdrm_clocks_init(struct sdrm_device *sdrm,
> +			    struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +
> +static void sdrm_clocks_destroy(struct sdrm_device *sdrm)
> +{
> +}
> +#endif
> +
> +#if defined CONFIG_OF && defined CONFIG_REGULATOR
> +
> +#define SUPPLY_SUFFIX "-supply"
> +
> +/*
> + * Regulator handling code.
> + *
> + * Here we handle the num-supplies and vin*-supply properties of our
> + * "simple-framebuffer" dt node. This is necessary so that we can make sure
> + * that any regulators needed by the display hardware that the bootloader
> + * set up for us (and for which it provided a simplefb dt node), stay up,
> + * for the life of the simplefb driver.
> + *
> + * When the driver unloads, we cleanly disable, and then release the
> + * regulators.
> + *
> + * We only complain about errors here, no action is taken as the most likely
> + * error can only happen due to a mismatch between the bootloader which set
> + * up simplefb, and the regulator definitions in the device tree. Chances are
> + * that there are no adverse effects, and if there are, a clean teardown of
> + * the fb probe will not help us much either. So just complain and carry on,
> + * and hope that the user actually gets a working fb at the end of things.
> + */
> +static int sdrm_regulators_init(struct sdrm_device *sdrm,
> +				struct platform_device *pdev)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	struct regulator *regulator;
> +	int count = 0, i = 0, ret;
> +	struct property *prop;
> +	const char *p;
> +
> +	if (dev_get_platdata(&pdev->dev) || !np)
> +		return 0;
> +
> +	/* Count the number of regulator supplies */
> +	for_each_property_of_node(np, prop) {
> +		p = strstr(prop->name, SUPPLY_SUFFIX);
> +		if (p && p != prop->name)
> +			count++;
> +	}
> +
> +	if (!count)
> +		return 0;
> +
> +	sdrm->regulators = devm_kcalloc(&pdev->dev, count,
> +					sizeof(struct regulator *),
> +					GFP_KERNEL);
> +	if (!sdrm->regulators)
> +		return -ENOMEM;
> +
> +	/* Get all the regulators */
> +	for_each_property_of_node(np, prop) {
> +		char name[32]; /* 32 is max size of property name */
> +
> +		p = strstr(prop->name, SUPPLY_SUFFIX);
> +		if (!p || p == prop->name)
> +			continue;
> +
> +		strlcpy(name, prop->name,
> +			strlen(prop->name) - strlen(SUPPLY_SUFFIX) + 1);
> +		regulator = devm_regulator_get_optional(&pdev->dev, name);
> +		if (IS_ERR(regulator)) {
> +			if (PTR_ERR(regulator) == -EPROBE_DEFER)
> +				return -EPROBE_DEFER;
> +			dev_err(&pdev->dev, "regulator %s not found: %ld\n",
> +				name, PTR_ERR(regulator));
> +			continue;
> +		}
> +		sdrm->regulators[i++] = regulator;
> +	}
> +	sdrm->regulator_count = i;
> +
> +	/* Enable all the regulators */
> +	for (i = 0; i < sdrm->regulator_count; i++) {
> +		ret = regulator_enable(sdrm->regulators[i]);
> +		if (ret) {
> +			dev_err(&pdev->dev,
> +				"failed to enable regulator %d: %d\n",
> +				i, ret);
> +			devm_regulator_put(sdrm->regulators[i]);
> +			sdrm->regulators[i] = NULL;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static void sdrm_regulators_destroy(struct sdrm_device *sdrm)
> +{
> +	int i;
> +
> +	if (!sdrm->regulators)
> +		return;
> +
> +	for (i = 0; i < sdrm->regulator_count; i++)
> +		if (sdrm->regulators[i])
> +			regulator_disable(sdrm->regulators[i]);
> +}
> +#else
> +static int sdrm_regulators_init(struct sdrm_device *sdrm,
> +				struct platform_device *pdev)
> +{
> +	return 0;
> +}
> +
> +static void sdrm_regulators_destroy(struct sdrm_device *sdrm)
> +{
> +}
> +#endif
> +
> +static int parse_dt(struct platform_device *pdev,
> +		    struct simplefb_platform_data *mode)
> +{
> +	struct device_node *np = pdev->dev.of_node;
> +	const char *format;
> +	int ret;
> +
> +	if (!np)
> +		return -ENODEV;
> +
> +	ret = of_property_read_u32(np, "width", &mode->width);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't parse width property\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(np, "height", &mode->height);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't parse height property\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_u32(np, "stride", &mode->stride);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't parse stride property\n");
> +		return ret;
> +	}
> +
> +	ret = of_property_read_string(np, "format", &format);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't parse format property\n");
> +		return ret;
> +	}
> +	mode->format = format;
> +
> +	return 0;
> +}
> +
> +static struct simplefb_format simplefb_formats[] = SIMPLEFB_FORMATS;
> +
> +int sdrm_pdev_init(struct sdrm_device *sdrm)
> +{
> +	struct platform_device *pdev = sdrm->ddev->platformdev;
> +	struct simplefb_platform_data *mode = pdev->dev.platform_data;
> +	struct simplefb_platform_data pmode;
> +	struct resource *mem;
> +	unsigned int depth;
> +	int ret, i, bpp;
> +
> +	if (!mode) {
> +		mode = &pmode;
> +		ret = parse_dt(pdev, mode);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!mem) {
> +		dev_err(sdrm->ddev->dev, "No memory resource\n");
> +		return -ENODEV;
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(simplefb_formats); ++i) {
> +		if (strcmp(mode->format, simplefb_formats[i].name))
> +			continue;
> +
> +		sdrm->fb_sformat = &simplefb_formats[i];
> +		sdrm->fb_format = simplefb_formats[i].fourcc;
> +		sdrm->fb_width = mode->width;
> +		sdrm->fb_height = mode->height;
> +		sdrm->fb_stride = mode->stride;
> +		sdrm->fb_base = mem->start;
> +		sdrm->fb_size = resource_size(mem);
> +		break;
> +	}
> +
> +	if (i >= ARRAY_SIZE(simplefb_formats)) {
> +		dev_err(sdrm->ddev->dev, "Unknown format %s\n", mode->format);
> +		return -ENODEV;
> +	}
> +
> +	switch (sdrm->fb_format) {
> +	case DRM_FORMAT_RGB565:
> +	case DRM_FORMAT_XRGB1555:
> +	case DRM_FORMAT_ARGB1555:
> +	case DRM_FORMAT_RGB888:
> +	case DRM_FORMAT_XRGB8888:
> +	case DRM_FORMAT_ARGB8888:
> +	case DRM_FORMAT_ABGR8888:
> +	case DRM_FORMAT_XRGB2101010:
> +	case DRM_FORMAT_ARGB2101010:
> +		/*
> +		 * You must adjust sdrm_put() whenever you add a new format
> +		 * here, otherwise, blitting operations will not work.
> +		 * Furthermore, include/linux/platform_data/simplefb.h needs
> +		 * to be adjusted so the platform-device actually allows this
> +		 * format.
> +		 */
> +		break;
> +	default:
> +		dev_err(sdrm->ddev->dev, "Unsupported format %s\n",
> +			mode->format);
> +		return -ENODEV;
> +	}
> +
> +	drm_fb_get_bpp_depth(sdrm->fb_format, &depth, &bpp);
> +	if (!bpp) {
> +		dev_err(sdrm->ddev->dev, "Unknown format %s\n", mode->format);
> +		return -ENODEV;
> +	}
> +
> +	if (sdrm->fb_size < sdrm->fb_stride * sdrm->fb_height) {
> +		dev_err(sdrm->ddev->dev, "FB too small\n");
> +		return -ENODEV;
> +	} else if ((bpp + 7) / 8 * sdrm->fb_width > sdrm->fb_stride) {
> +		dev_err(sdrm->ddev->dev, "Invalid stride\n");
> +		return -ENODEV;
> +	}
> +
> +	sdrm->fb_bpp = bpp;
> +
> +	sdrm->fb_map = ioremap_wc(sdrm->fb_base, sdrm->fb_size);
> +	if (!sdrm->fb_map) {
> +		dev_err(sdrm->ddev->dev, "cannot remap VMEM\n");
> +		return -EIO;
> +	}
> +
> +	DRM_DEBUG_KMS("format: %s\n", drm_get_format_name(sdrm->fb_format));
> +
> +	return 0;
> +}
> +
> +void sdrm_pdev_destroy(struct sdrm_device *sdrm)
> +{
> +	if (sdrm->fb_map) {
> +		iounmap(sdrm->fb_map);
> +		sdrm->fb_map = NULL;
> +	}
> +}
> +
> +static int sdrm_simplefb_probe(struct platform_device *pdev)
> +{
> +	struct sdrm_device *sdrm;
> +	struct drm_device *ddev;
> +	int ret;
> +
> +	ddev = drm_dev_alloc(&sdrm_drm_driver, &pdev->dev);
> +	if (!ddev)
> +		return -ENOMEM;
> +
> +	sdrm = kzalloc(sizeof(*sdrm), GFP_KERNEL);
> +	if (!sdrm)
> +		goto err_free;
> +
> +	ddev->platformdev = pdev;

I'm kinda trying to deprecate drm_device->platformdev. If you want it, pls
store it in sdrm_device. Or pass it around explicitly.
-Daniel

> +	ddev->dev_private = sdrm;
> +	sdrm->ddev = ddev;
> +
> +	ret = sdrm_pdev_init(sdrm);
> +	if (ret)
> +		goto err_free;
> +
> +	ret = sdrm_drm_modeset_init(sdrm);
> +	if (ret)
> +		goto err_destroy;
> +
> +	ret = sdrm_clocks_init(sdrm, pdev);
> +	if (ret < 0)
> +		goto err_cleanup;
> +
> +	ret = sdrm_regulators_init(sdrm, pdev);
> +	if (ret < 0)
> +		goto err_clocks;
> +
> +	platform_set_drvdata(pdev, ddev);
> +	ret = drm_dev_register(ddev, 0);
> +	if (ret)
> +		goto err_regulators;
> +
> +	DRM_INFO("Initialized %s on minor %d\n", ddev->driver->name,
> +		 ddev->primary->index);
> +
> +	return 0;
> +
> +err_regulators:
> +	sdrm_regulators_destroy(sdrm);
> +err_clocks:
> +	sdrm_clocks_destroy(sdrm);
> +err_cleanup:
> +	drm_mode_config_cleanup(ddev);
> +err_destroy:
> +	sdrm_pdev_destroy(sdrm);
> +err_free:
> +	drm_dev_unref(ddev);
> +	kfree(sdrm);
> +
> +	return ret;
> +}
> +
> +static int sdrm_simplefb_remove(struct platform_device *pdev)
> +{
> +	struct drm_device *ddev = platform_get_drvdata(pdev);
> +	struct sdrm_device *sdrm = ddev->dev_private;
> +
> +	drm_dev_unregister(ddev);
> +	drm_mode_config_cleanup(ddev);
> +
> +	/* protect fb_map removal against sdrm_blit() */
> +	drm_modeset_lock_all(ddev);
> +	sdrm_pdev_destroy(sdrm);
> +	drm_modeset_unlock_all(ddev);
> +
> +	sdrm_regulators_destroy(sdrm);
> +	sdrm_clocks_destroy(sdrm);
> +
> +	drm_dev_unref(ddev);
> +	kfree(sdrm);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id simplefb_of_match[] = {
> +	{ .compatible = "simple-framebuffer", },
> +	{ },
> +};
> +MODULE_DEVICE_TABLE(of, simplefb_of_match);
> +
> +static struct platform_driver sdrm_simplefb_driver = {
> +	.probe = sdrm_simplefb_probe,
> +	.remove = sdrm_simplefb_remove,
> +	.driver = {
> +		.name = "simple-framebuffer",
> +		.mod_name = KBUILD_MODNAME,
> +		.owner = THIS_MODULE,
> +		.of_match_table = simplefb_of_match,
> +	},
> +};
> +
> +static int __init sdrm_init(void)
> +{
> +	int ret;
> +	struct device_node *np;
> +
> +	ret = platform_driver_register(&sdrm_simplefb_driver);
> +	if (ret)
> +		return ret;
> +
> +	if (IS_ENABLED(CONFIG_OF_ADDRESS) && of_chosen) {
> +		for_each_child_of_node(of_chosen, np) {
> +			if (of_device_is_compatible(np, "simple-framebuffer"))
> +				of_platform_device_create(np, NULL, NULL);
> +		}
> +	}
> +
> +	return 0;
> +}
> +module_init(sdrm_init);
> +
> +static void __exit sdrm_exit(void)
> +{
> +	platform_driver_unregister(&sdrm_simplefb_driver);
> +}
> +module_exit(sdrm_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("David Herrmann <dh.herrmann@xxxxxxxxx>");
> +MODULE_DESCRIPTION("Simple firmware framebuffer DRM driver");
> +MODULE_ALIAS("platform:simple-framebuffer");
> diff --git a/drivers/gpu/drm/simpledrm/simpledrm_gem.c b/drivers/gpu/drm/simpledrm/simpledrm_gem.c
> new file mode 100644
> index 0000000..81bd7c5
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/simpledrm_gem.c
> @@ -0,0 +1,274 @@
> +/*
> + * SimpleDRM firmware framebuffer driver
> + * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@xxxxxxxxx>
> + *
> + * 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 <drm/drmP.h>
> +#include <linux/dma-buf.h>
> +#include <linux/errno.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/slab.h>
> +#include <linux/vmalloc.h>
> +
> +#include "simpledrm.h"
> +
> +int sdrm_gem_get_pages(struct sdrm_gem_object *obj)
> +{
> +	size_t num, i;
> +
> +	if (obj->vmapping)
> +		return 0;
> +
> +	if (obj->base.import_attach) {
> +		obj->vmapping = dma_buf_vmap(obj->base.import_attach->dmabuf);
> +		return !obj->vmapping ? -ENOMEM : 0;
> +	}
> +
> +	num = obj->base.size >> PAGE_SHIFT;
> +	obj->pages = drm_malloc_ab(num, sizeof(*obj->pages));
> +	if (!obj->pages)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num; ++i) {
> +		obj->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO);
> +		if (!obj->pages[i])
> +			goto error;
> +	}
> +
> +	obj->vmapping = vmap(obj->pages, num, 0, PAGE_KERNEL);
> +	if (!obj->vmapping)
> +		goto error;
> +
> +	return 0;
> +
> +error:
> +	while (i > 0)
> +		__free_pages(obj->pages[--i], 0);
> +
> +	drm_free_large(obj->pages);
> +	obj->pages = NULL;
> +	return -ENOMEM;
> +}

There's a helper for this in drm_gem.c. Same for put_pages.
> +
> +static void sdrm_gem_put_pages(struct sdrm_gem_object *obj)
> +{
> +	size_t num, i;
> +
> +	if (!obj->vmapping)
> +		return;
> +
> +	if (obj->base.import_attach) {
> +		dma_buf_vunmap(obj->base.import_attach->dmabuf, obj->vmapping);
> +		obj->vmapping = NULL;
> +		return;
> +	}
> +
> +	vunmap(obj->vmapping);
> +	obj->vmapping = NULL;
> +
> +	num = obj->base.size >> PAGE_SHIFT;
> +	for (i = 0; i < num; ++i)
> +		__free_pages(obj->pages[i], 0);
> +
> +	drm_free_large(obj->pages);
> +	obj->pages = NULL;
> +}
> +
> +struct sdrm_gem_object *sdrm_gem_alloc_object(struct drm_device *ddev,
> +					      size_t size)
> +{
> +	struct sdrm_gem_object *obj;
> +
> +	WARN_ON(!size || (size & ~PAGE_MASK) != 0);
> +
> +	obj = kzalloc(sizeof(*obj), GFP_KERNEL);
> +	if (!obj)
> +		return NULL;
> +
> +	drm_gem_private_object_init(ddev, &obj->base, size);
> +	return obj;
> +}
> +
> +void sdrm_gem_free_object(struct drm_gem_object *gobj)
> +{
> +	struct sdrm_gem_object *obj = to_sdrm_bo(gobj);
> +	struct drm_device *ddev = gobj->dev;
> +
> +	if (obj->pages) {
> +		/* kill all user-space mappings */
> +		drm_vma_node_unmap(&gobj->vma_node,
> +				   ddev->anon_inode->i_mapping);
> +		sdrm_gem_put_pages(obj);
> +	}
> +
> +	if (gobj->import_attach)
> +		drm_prime_gem_destroy(gobj, obj->sg);
> +
> +	drm_gem_free_mmap_offset(gobj);
> +	drm_gem_object_release(gobj);
> +	kfree(obj);
> +}
> +
> +int sdrm_dumb_create(struct drm_file *dfile, struct drm_device *ddev,
> +		     struct drm_mode_create_dumb *args)
> +{
> +	struct sdrm_gem_object *obj;
> +	int r;
> +
> +	if (args->flags)
> +		return -EINVAL;
> +
> +	/* overflow checks are done by DRM core */
> +	args->pitch = (args->bpp + 7) / 8 * args->width;
> +	args->size = PAGE_ALIGN(args->pitch * args->height);
> +
> +	obj = sdrm_gem_alloc_object(ddev, args->size);
> +	if (!obj)
> +		return -ENOMEM;
> +
> +	r = drm_gem_handle_create(dfile, &obj->base, &args->handle);
> +	if (r) {
> +		drm_gem_object_unreference_unlocked(&obj->base);
> +		return r;
> +	}
> +
> +	/* handle owns a reference */
> +	drm_gem_object_unreference_unlocked(&obj->base);
> +	return 0;
> +}
> +
> +int sdrm_dumb_destroy(struct drm_file *dfile, struct drm_device *ddev,
> +		      uint32_t handle)
> +{
> +	return drm_gem_handle_delete(dfile, handle);
> +}

I wonder whether some dumb+gem helpers wouldn't be useful to roll out. At
least drm_dumb_gem_destroy.c would be pretty simple.

> +
> +int sdrm_dumb_map_offset(struct drm_file *dfile, struct drm_device *ddev,
> +			 uint32_t handle, uint64_t *offset)
> +{
> +	struct drm_gem_object *gobj;
> +	int r;
> +
> +	mutex_lock(&ddev->struct_mutex);

There's still some struct mutex here.

> +
> +	gobj = drm_gem_object_lookup(dfile, handle);
> +	if (!gobj) {
> +		r = -ENOENT;
> +		goto out_unlock;
> +	}
> +
> +	r = drm_gem_create_mmap_offset(gobj);
> +	if (r)
> +		goto out_unref;
> +
> +	*offset = drm_vma_node_offset_addr(&gobj->vma_node);
> +
> +out_unref:
> +	drm_gem_object_unreference(gobj);
> +out_unlock:
> +	mutex_unlock(&ddev->struct_mutex);
> +	return r;
> +}
> +
> +int sdrm_drm_mmap(struct file *filp, struct vm_area_struct *vma)
> +{
> +	struct drm_file *priv = filp->private_data;
> +	struct drm_device *dev = priv->minor->dev;
> +	struct drm_vma_offset_node *node;
> +	struct drm_gem_object *gobj;
> +	struct sdrm_gem_object *obj;
> +	size_t size, i, num;
> +	int r;
> +
> +	if (drm_device_is_unplugged(dev))
> +		return -ENODEV;
> +
> +	drm_vma_offset_lock_lookup(dev->vma_offset_manager);
> +	node = drm_vma_offset_exact_lookup_locked(dev->vma_offset_manager,
> +						  vma->vm_pgoff,
> +						  vma_pages(vma));
> +	drm_vma_offset_unlock_lookup(dev->vma_offset_manager);
> +
> +	if (!drm_vma_node_is_allowed(node, filp))
> +		return -EACCES;
> +
> +	gobj = container_of(node, struct drm_gem_object, vma_node);
> +	obj = to_sdrm_bo(gobj);
> +	size = drm_vma_node_size(node) << PAGE_SHIFT;
> +	if (size < vma->vm_end - vma->vm_start)
> +		return r;
> +
> +	r = sdrm_gem_get_pages(obj);
> +	if (r < 0)
> +		return r;
> +
> +	/* prevent dmabuf-imported mmap to user-space */
> +	if (!obj->pages)
> +		return -EACCES;
> +
> +	vma->vm_flags |= VM_DONTEXPAND;
> +	vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> +
> +	num = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
> +	for (i = 0; i < num; ++i) {
> +		r = vm_insert_page(vma, vma->vm_start + i * PAGE_SIZE,
> +				   obj->pages[i]);
> +		if (r < 0) {
> +			if (i > 0)
> +				zap_vma_ptes(vma, vma->vm_start, i * PAGE_SIZE);
> +			return r;
> +		}
> +	}
> +
> +	return 0;
> +}

Why can't we just redirect to the underlying shmem mmap here (after
argument checking)?

> +
> +struct drm_gem_object *sdrm_gem_prime_import(struct drm_device *ddev,
> +					     struct dma_buf *dma_buf)
> +{
> +	struct dma_buf_attachment *attach;
> +	struct sdrm_gem_object *obj;
> +	struct sg_table *sg;
> +	int ret;
> +
> +	/* need to attach */
> +	attach = dma_buf_attach(dma_buf, ddev->dev);
> +	if (IS_ERR(attach))
> +		return ERR_CAST(attach);
> +
> +	get_dma_buf(dma_buf);
> +
> +	sg = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
> +	if (IS_ERR(sg)) {
> +		ret = PTR_ERR(sg);
> +		goto fail_detach;
> +	}
> +
> +	/*
> +	 * dma_buf_vmap() gives us a page-aligned mapping, so lets bump the
> +	 * size of the dma-buf to the next page-boundary
> +	 */

dma_buf should be page-aligned already. Not sure we enforce that, but it's
in practice a given.

> +	obj = sdrm_gem_alloc_object(ddev, PAGE_ALIGN(dma_buf->size));
> +	if (!obj) {
> +		ret = -ENOMEM;
> +		goto fail_unmap;
> +	}
> +
> +	obj->sg = sg;
> +	obj->base.import_attach = attach;
> +
> +	return &obj->base;
> +
> +fail_unmap:
> +	dma_buf_unmap_attachment(attach, sg, DMA_BIDIRECTIONAL);
> +fail_detach:
> +	dma_buf_detach(dma_buf, attach);
> +	dma_buf_put(dma_buf);
> +	return ERR_PTR(ret);
> +}
> diff --git a/drivers/gpu/drm/simpledrm/simpledrm_kms.c b/drivers/gpu/drm/simpledrm/simpledrm_kms.c
> new file mode 100644
> index 0000000..00e50d9
> --- /dev/null
> +++ b/drivers/gpu/drm/simpledrm/simpledrm_kms.c
> @@ -0,0 +1,258 @@
> +/*
> + * SimpleDRM firmware framebuffer driver
> + * Copyright (c) 2012-2014 David Herrmann <dh.herrmann@xxxxxxxxx>
> + *
> + * 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 <drm/drmP.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_crtc.h>
> +#include <drm/drm_crtc_helper.h>
> +#include <drm/drm_gem.h>
> +#include <drm/drm_simple_kms_helper.h>
> +#include <linux/slab.h>
> +
> +#include "simpledrm.h"
> +
> +static const uint32_t sdrm_formats[] = {
> +	DRM_FORMAT_RGB565,
> +	DRM_FORMAT_ARGB8888,
> +	DRM_FORMAT_XRGB8888,
> +};
> +
> +static int sdrm_conn_get_modes(struct drm_connector *conn)
> +{
> +	struct sdrm_device *sdrm = conn->dev->dev_private;
> +	struct drm_display_mode *mode;
> +
> +	mode = drm_cvt_mode(sdrm->ddev, sdrm->fb_width, sdrm->fb_height,
> +			    60, false, false, false);
> +	if (!mode)
> +		return 0;
> +
> +	mode->type = DRM_MODE_TYPE_DRIVER | DRM_MODE_TYPE_PREFERRED;
> +	drm_mode_set_name(mode);
> +	drm_mode_probed_add(conn, mode);
> +
> +	return 1;
> +}
> +
> +static const struct drm_connector_helper_funcs sdrm_conn_hfuncs = {
> +	.get_modes = sdrm_conn_get_modes,
> +	.best_encoder = drm_atomic_helper_best_encoder,
> +};
> +
> +static enum drm_connector_status sdrm_conn_detect(struct drm_connector *conn,
> +						  bool force)
> +{
> +	/*
> +	 * We simulate an always connected monitor. simple-fb doesn't
> +	 * provide any way to detect whether the connector is active. Hence,
> +	 * signal DRM core that it is always connected.
> +	 */
> +
> +	return connector_status_connected;
> +}
> +
> +static const struct drm_connector_funcs sdrm_conn_ops = {
> +	.dpms = drm_atomic_helper_connector_dpms,
> +	.reset = drm_atomic_helper_connector_reset,
> +	.detect = sdrm_conn_detect,
> +	.fill_modes = drm_helper_probe_single_connector_modes,
> +	.destroy = drm_connector_cleanup,
> +	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> +	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> +};
> +
> +static inline struct sdrm_device *
> +pipe_to_sdrm(struct drm_simple_display_pipe *pipe)
> +{
> +	return container_of(pipe, struct sdrm_device, pipe);
> +}
> +
> +static void sdrm_crtc_send_vblank_event(struct drm_crtc *crtc)
> +{
> +	if (crtc->state && crtc->state->event) {
> +		spin_lock_irq(&crtc->dev->event_lock);
> +		drm_crtc_send_vblank_event(crtc, crtc->state->event);
> +		spin_unlock_irq(&crtc->dev->event_lock);
> +		crtc->state->event = NULL;
> +	}
> +}
> +
> +void sdrm_display_pipe_update(struct drm_simple_display_pipe *pipe,
> +			      struct drm_plane_state *plane_state)
> +{
> +	struct drm_framebuffer *fb = pipe->plane.state->fb;
> +	struct sdrm_device *sdrm = pipe_to_sdrm(pipe);
> +
> +	sdrm_crtc_send_vblank_event(&pipe->crtc);
> +
> +	if (fb) {
> +		pipe->plane.fb = fb;
> +		sdrm_dirty_all_locked(sdrm);
> +	}
> +}
> +
> +static void sdrm_display_pipe_enable(struct drm_simple_display_pipe *pipe,
> +				     struct drm_crtc_state *crtc_state)
> +{
> +	sdrm_crtc_send_vblank_event(&pipe->crtc);
> +}
> +
> +static void sdrm_display_pipe_disable(struct drm_simple_display_pipe *pipe)
> +{
> +	sdrm_crtc_send_vblank_event(&pipe->crtc);
> +}
> +
> +static const struct drm_simple_display_pipe_funcs sdrm_pipe_funcs = {
> +	.update = sdrm_display_pipe_update,
> +	.enable = sdrm_display_pipe_enable,
> +	.disable = sdrm_display_pipe_disable,
> +};
> +
> +static int sdrm_fb_create_handle(struct drm_framebuffer *fb,
> +				 struct drm_file *dfile,
> +				 unsigned int *handle)
> +{
> +	struct sdrm_framebuffer *sfb = to_sdrm_fb(fb);
> +
> +	return drm_gem_handle_create(dfile, &sfb->obj->base, handle);
> +}
> +
> +static void sdrm_fb_destroy(struct drm_framebuffer *fb)
> +{
> +	struct sdrm_framebuffer *sfb = to_sdrm_fb(fb);
> +
> +	drm_framebuffer_cleanup(fb);
> +	drm_gem_object_unreference_unlocked(&sfb->obj->base);
> +	kfree(sfb);
> +}
> +
> +static const struct drm_framebuffer_funcs sdrm_fb_ops = {
> +	.create_handle = sdrm_fb_create_handle,
> +	.dirty = sdrm_dirty,
> +	.destroy = sdrm_fb_destroy,
> +};
> +
> +static struct drm_framebuffer *sdrm_fb_create(struct drm_device *ddev,
> +					      struct drm_file *dfile,
> +					      const struct drm_mode_fb_cmd2 *cmd)
> +{
> +	struct sdrm_framebuffer *fb;
> +	struct drm_gem_object *gobj;
> +	u32 bpp, size;
> +	int ret;
> +	void *err;
> +
> +	if (cmd->flags)
> +		return ERR_PTR(-EINVAL);
> +
> +	gobj = drm_gem_object_lookup(dfile, cmd->handles[0]);
> +	if (!gobj)
> +		return ERR_PTR(-EINVAL);
> +
> +	fb = kzalloc(sizeof(*fb), GFP_KERNEL);
> +	if (!fb) {
> +		err = ERR_PTR(-ENOMEM);
> +		goto err_unref;
> +	}
> +	fb->obj = to_sdrm_bo(gobj);
> +
> +	fb->base.pitches[0] = cmd->pitches[0];
> +	fb->base.offsets[0] = cmd->offsets[0];
> +	fb->base.width = cmd->width;
> +	fb->base.height = cmd->height;
> +	fb->base.pixel_format = cmd->pixel_format;
> +	drm_fb_get_bpp_depth(cmd->pixel_format, &fb->base.depth,
> +			     &fb->base.bits_per_pixel);
> +
> +	/*
> +	 * width/height are already clamped into min/max_width/height range,
> +	 * so overflows are not possible
> +	 */
> +
> +	bpp = (fb->base.bits_per_pixel + 7) / 8;
> +	size = cmd->pitches[0] * cmd->height;
> +	if (!bpp ||
> +	    bpp > 4 ||
> +	    cmd->pitches[0] < bpp * fb->base.width ||
> +	    cmd->pitches[0] > 0xffffU ||
> +	    size + fb->base.offsets[0] < size ||
> +	    size + fb->base.offsets[0] > fb->obj->base.size) {
> +		err = ERR_PTR(-EINVAL);
> +		goto err_free;
> +	}
> +
> +	ret = drm_framebuffer_init(ddev, &fb->base, &sdrm_fb_ops);
> +	if (ret < 0) {
> +		err = ERR_PTR(ret);
> +		goto err_free;
> +	}
> +
> +	DRM_DEBUG_KMS("[FB:%d] pixel_format: %s\n", fb->base.base.id,
> +		      drm_get_format_name(fb->base.pixel_format));
> +
> +	return &fb->base;
> +
> +err_free:
> +	kfree(fb);
> +err_unref:
> +	drm_gem_object_unreference_unlocked(gobj);
> +
> +	return err;
> +}
> +
> +static const struct drm_mode_config_funcs sdrm_mode_config_ops = {
> +	.fb_create = sdrm_fb_create,
> +	.atomic_check = drm_atomic_helper_check,
> +	.atomic_commit = drm_atomic_helper_commit,
> +};
> +
> +int sdrm_drm_modeset_init(struct sdrm_device *sdrm)
> +{
> +	struct drm_connector *conn = &sdrm->conn;
> +	struct drm_device *ddev = sdrm->ddev;
> +	int ret;
> +
> +	drm_mode_config_init(ddev);
> +	ddev->mode_config.min_width = sdrm->fb_width;
> +	ddev->mode_config.max_width = sdrm->fb_width;
> +	ddev->mode_config.min_height = sdrm->fb_height;
> +	ddev->mode_config.max_height = sdrm->fb_height;
> +	ddev->mode_config.preferred_depth = sdrm->fb_bpp;
> +	ddev->mode_config.funcs = &sdrm_mode_config_ops;
> +
> +	drm_connector_helper_add(conn, &sdrm_conn_hfuncs);
> +	ret = drm_connector_init(ddev, conn, &sdrm_conn_ops,
> +				 DRM_MODE_CONNECTOR_VIRTUAL);
> +	if (ret)
> +		goto err_cleanup;
> +
> +	ret = drm_mode_create_dirty_info_property(ddev);
> +	if (ret)
> +		goto err_cleanup;
> +
> +	drm_object_attach_property(&conn->base,
> +				   ddev->mode_config.dirty_info_property,
> +				   DRM_MODE_DIRTY_ON);

dirty_info_property is gone.

> +
> +	ret = drm_simple_display_pipe_init(ddev, &sdrm->pipe, &sdrm_pipe_funcs,
> +					   sdrm_formats,
> +					   ARRAY_SIZE(sdrm_formats), conn);
> +	if (ret)
> +		goto err_cleanup;
> +
> +	drm_mode_config_reset(ddev);
> +
> +	return 0;
> +
> +err_cleanup:
> +	drm_mode_config_cleanup(ddev);
> +
> +	return ret;
> +}
> --
> 2.8.2
> 
> _______________________________________________
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> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch