[RFC v2 1/1] drm: allow to use mmuless SoC
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Wed Nov 30 13:27:50 UTC 2016
Hi Benjamin,
Thank you for the patch.
On Wednesday 30 Nov 2016 14:19:18 Benjamin Gaignard wrote:
> Some SoC without MMU have display driver where a drm/kms driver
> could be implemented.
> Before doing such kind of thing drm/kms must allow to use mmuless
> devices.
> This patch propose to remove MMU configuration flag and add some
> cma helpers functions to help implementing mmuless display driver
>
> version 2:
> - define get_fb_unmapped_area() in drivers/video/fbdev/core/fbmem.c
> if HAVE_ARCH_FB_UNMAPPED_AREA is set and get_fb_unmapped_area not
> already defined in the architecture
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard at linaro.org>
> ---
> drivers/gpu/drm/Kconfig | 4 +--
> drivers/gpu/drm/drm_fb_cma_helper.c | 4 +++
> drivers/gpu/drm/drm_gem_cma_helper.c | 62 +++++++++++++++++++++++++++++++++
> drivers/gpu/drm/drm_vm.c | 4 +++
> drivers/video/fbdev/core/fbmem.c | 15 +++++++++
> include/drm/drm_gem_cma_helper.h | 6 ++++
> 6 files changed, 93 insertions(+), 2 deletions(-)
[snip]
> diff --git a/drivers/video/fbdev/core/fbmem.c
> b/drivers/video/fbdev/core/fbmem.c index 76c1ad9..54488ee 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1492,6 +1492,21 @@ static long fb_compat_ioctl(struct file *file,
> unsigned int cmd, return 0;
> }
>
> +#if defined(HAVE_ARCH_FB_UNMAPPED_AREA) && !defined(get_fb_unmapped_area)
Only blackfin and sparc define HAVE_ARCH_FB_UNMAPPED_AREA, and both of them
provide an implementation of get_fb_unmapped_area().
> +unsigned long get_fb_unmapped_area(struct file *filp,
> + unsigned long addr, unsigned long len,
> + unsigned long pgoff, unsigned long flags)
> +{
> + struct fb_info * const info = filp->private_data;
> + unsigned long fb_size = PAGE_ALIGN(info->fix.smem_len);
> +
> + if (pgoff > fb_size || len > fb_size - pgoff)
> + return -EINVAL;
> +
> + return (unsigned long)info->screen_base + pgoff;
> +}
> +#endif
> +
> static const struct file_operations fb_fops = {
> .owner = THIS_MODULE,
> .read = fb_read,
[snip]
--
Regards,
Laurent Pinchart
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