[PATCH] Staging: fbtft: Fix iomem dereference

[PATCH] Staging: fbtft: Fix iomem dereference

[Ronit Halder]

This patch fixes the warning generated by sparse
"cast removes address space of expression" by using ioread16
function insted of directly dereferencing I/O memory.

Signed-off-by: Ronit halder <ronit.crj@gmail.com>
---
 drivers/staging/fbtft/fb_agm1264k-fl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/fbtft/fb_agm1264k-fl.c b/drivers/staging/fbtft/fb_agm1264k-fl.c
index 94dd49c..59826a4 100644
--- a/drivers/staging/fbtft/fb_agm1264k-fl.c
+++ b/drivers/staging/fbtft/fb_agm1264k-fl.c
@@ -273,7 +273,7 @@ construct_line_bitmap(struct fbtft_par *par, u8 *dest, signed short *src,
 
 static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 {
-	u16 *vmem16 = (u16 *)par->info->screen_base;
+	void __iomem *vmem16 = (u16 __iomem *)par->info->screen_base;
 	u8 *buf = par->txbuf.buf;
 	int x, y;
 	int ret = 0;
@@ -290,7 +290,8 @@ static int write_vmem(struct fbtft_par *par, size_t offset, size_t len)
 	/* converting to grayscale16 */
 	for (x = 0; x < par->info->var.xres; ++x)
 		for (y = 0; y < par->info->var.yres; ++y) {
-			u16 pixel = vmem16[y *  par->info->var.xres + x];
+			u16 pixel = ioread16(vmem16 +
+				y * par->info->var.xres + x);
 			u16 b = pixel & 0x1f;
 			u16 g = (pixel & (0x3f << 5)) >> 5;
 			u16 r = (pixel & (0x1f << (5 + 6))) >> (5 + 6);
-- 
2.4.0.GIT

Re: [PATCH] Staging: fbtft: Fix iomem dereference

[Dan Carpenter]

On Tue, Aug 18, 2015 at 12:16:57PM +0530, Ronit Halder wrote:
> This patch fixes the warning generated by sparse
> "cast removes address space of expression" by using ioread16
> function insted of directly dereferencing I/O memory.
> 
> Signed-off-by: Ronit halder <ronit.crj@gmail.com>

Are these really iomem pointers?  A lot of drivers use a fake
screen_base which is just a buffer of normal memory.

regards,
dan carpenter

Re: [PATCH] Staging: fbtft: Fix iomem dereference

[Ronit Halder]

Yes, it is not I/O memory address. I was wrong on that.
But it makes sparse happy.
Is here any side effect of using ioread16() ?

regards,
ronit

On Tue, Aug 18, 2015 at 2:27 PM, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> On Tue, Aug 18, 2015 at 12:16:57PM +0530, Ronit Halder wrote:
>> This patch fixes the warning generated by sparse
>> "cast removes address space of expression" by using ioread16
>> function insted of directly dereferencing I/O memory.
>>
>> Signed-off-by: Ronit halder <ronit.crj@gmail.com>
>
> Are these really iomem pointers?  A lot of drivers use a fake
> screen_base which is just a buffer of normal memory.
>
> regards,
> dan carpenter
>