linux-kernel - Re: [PATCH 3/3] fbdev: sh_mobile_lcdc: use dma_mmap

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Message-ID: <9666926.0rOsjgUcAB@avalon>
Date:	Wed, 25 Jul 2012 13:10:46 +0200
From:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:	Hideki EIRAKU <hdk@...l.co.jp>
Cc:	Russell King <linux@....linux.org.uk>,
	Pawel Osciak <pawel@...iak.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Mauro Carvalho Chehab <mchehab@...radead.org>,
	Florian Tobias Schandinat <FlorianSchandinat@....de>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, linux-fbdev@...r.kernel.org,
	Katsuya MATSUBARA <matsu@...l.co.jp>
Subject: Re: [PATCH 3/3] fbdev: sh_mobile_lcdc: use dma_mmap_coherent if available

Hi Eiraku-san,

Thank you for the patch.

On Wednesday 25 July 2012 15:29:24 Hideki EIRAKU wrote:
> fb_mmap() implemented in fbmem.c uses smem_start as the physical
> address of the frame buffer.  In the sh_mobile_lcdc driver, the
> smem_start is a dma_addr_t that is not a physical address when IOMMU is
> enabled.  dma_mmap_coherent() maps the address correctly.  It is
> available on ARM platforms.

This looks good to me, but will need to be rebased on top of the 
sh_mobile_lcdc patches currently queued for v3.6. You can find them in the 
fbdev-next branch of git://github.com/schandinat/linux-2.6.git.

In particular, these patches add support for overlays exported through 
additional fbdev devices. You will need to initialize .fb_mmap in both 
sh_mobile_lcdc_overlay_ops and sh_mobile_lcdc_ops.

> Signed-off-by: Hideki EIRAKU <hdk@...l.co.jp>
> ---
>  drivers/video/sh_mobile_lcdcfb.c |   14 ++++++++++++++
>  1 files changed, 14 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/video/sh_mobile_lcdcfb.c
> b/drivers/video/sh_mobile_lcdcfb.c index e672698..65732c4 100644
> --- a/drivers/video/sh_mobile_lcdcfb.c
> +++ b/drivers/video/sh_mobile_lcdcfb.c
> @@ -1393,6 +1393,17 @@ static int sh_mobile_lcdc_blank(int blank, struct
> fb_info *info) return 0;
>  }
> 
> +#ifdef ARCH_HAS_DMA_MMAP_COHERENT
> +static int
> +sh_mobile_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
> +{
> +	struct sh_mobile_lcdc_chan *ch = info->par;
> +
> +	return dma_mmap_coherent(ch->lcdc->dev, vma, ch->fb_mem,
> +				 ch->dma_handle, ch->fb_size);
> +}
> +#endif
> +
>  static struct fb_ops sh_mobile_lcdc_ops = {
>  	.owner          = THIS_MODULE,
>  	.fb_setcolreg	= sh_mobile_lcdc_setcolreg,
> @@ -1408,6 +1419,9 @@ static struct fb_ops sh_mobile_lcdc_ops = {
>  	.fb_release	= sh_mobile_release,
>  	.fb_check_var	= sh_mobile_check_var,
>  	.fb_set_par	= sh_mobile_set_par,
> +#ifdef ARCH_HAS_DMA_MMAP_COHERENT
> +	.fb_mmap	= sh_mobile_fb_mmap,
> +#endif
>  };
> 
>  static void
-- 
Regards,

Laurent Pinchart

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