Re: [PATCH v3 7/8] video: xilinxfb: Fix sparse warnings

On 05/31/2013 03:26 PM, Timur Tabi wrote:

On 05/31/2013 07:55 AM, Michal Simek wrote:

quoted

diff --git a/drivers/video/xilinxfb.c b/drivers/video/xilinxfb.c
index f3d4a69..e27a4f6 100644
--- a/drivers/video/xilinxfb.c
+++ b/drivers/video/xilinxfb.c

@@ -131,7 +131,7 @@ struct xilinxfb_drvdata {
 	dcr_host_t      dcr_host;
 	unsigned int    dcr_len;
 #endif
-	void		*fb_virt;	/* virt. address of the frame buffer */
+	void __iomem	*fb_virt;	/* virt. address of the frame buffer */
 	dma_addr_t	fb_phys;	/* phys. address of the frame buffer */
 	int		fb_alloced;	/* Flag, was the fb memory alloced? */

@@ -273,8 +273,10 @@ static int xilinxfb_assign(struct platform_device *pdev,
 		drvdata->fb_virt = ioremap(pdata->fb_phys, fbsize);
 	} else {
 		drvdata->fb_alloced = 1;
-		drvdata->fb_virt = dma_alloc_coherent(dev, PAGE_ALIGN(fbsize),
-					&drvdata->fb_phys, GFP_KERNEL);
+		drvdata->fb_virt = (__force void __iomem *)
+				   dma_alloc_coherent(dev, PAGE_ALIGN(fbsize),
+						      &drvdata->fb_phys,
+						      GFP_KERNEL);

I think this is wrong.  At least, it would be on PowerPC.
dma_alloc_coherent() allocates regular RAM, not I/O memory.  So it
should not be __iomem.

The same is for Microblaze. Driver shares fb_virt for IO memory
and for allocated memory. The purpose of this driver wasn't
to change the driver logic just resolved sparse warnings.
The other way is also wrong.
I have compiled this driver with ppc toolchain and it should
remove sparse warnings for PPC.

Thanks,
Michal

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/
Maintainer of Linux kernel - Xilinx Zynq ARM architecture
Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform