* [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary
@ 2015-09-16 20:00 Uwe Kleine-König
2015-09-17 6:10 ` Uwe Kleine-König
2015-09-21 6:09 ` Sascha Hauer
0 siblings, 2 replies; 3+ messages in thread
From: Uwe Kleine-König @ 2015-09-16 20:00 UTC (permalink / raw)
To: barebox
The reference manual (for the i.MX25 in my case) states:
This field must start at a location that enables a complete
picture to be stored in a 4 Mbyte memory boundary (A [21:0]). A
[31:22] has a fixed value for a picture’s image.
Check this condition for user-supplied framebuffer values and enforce it
for driver-allocated buffers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
drivers/video/imx.c | 49 +++++++++++++++++++++++++++++++++++++++----------
1 file changed, 39 insertions(+), 10 deletions(-)
diff --git a/drivers/video/imx.c b/drivers/video/imx.c
index b1066e1243fd..11d49c6cfbfd 100644
--- a/drivers/video/imx.c
+++ b/drivers/video/imx.c
@@ -24,6 +24,7 @@
#include <init.h>
#include <linux/clk.h>
#include <linux/err.h>
+#include <linux/sizes.h>
#include <asm-generic/div64.h>
#define LCDC_SSA 0x00
@@ -390,6 +391,37 @@ static struct fb_ops imxfb_ops = {
.fb_activate_var = imxfb_activate_var,
};
+static int imxfb_allocate_fbbuffer(const struct device_d *dev,
+ struct fb_info *info, void *forcefb)
+{
+ size_t fbsize = info->xres * info->yres * (info->bits_per_pixel >> 3);
+
+ /*
+ * The buffer must be completely contained in an aligned 4 MiB memory
+ * area.
+ */
+ if (forcefb) {
+ if (ALIGN((unsigned long)forcefb, SZ_4M) !=
+ ALIGN((unsigned long)forcefb + fbsize, SZ_4M)) {
+ dev_err(dev,
+ "provided frame buffer crosses a 4 MiB boundary\n");
+ return -EINVAL;
+ }
+ info->screen_base = forcefb;
+ } else {
+ /*
+ * memalign implements a stricter condition on the memory
+ * allocation as necessary, but in the absense of a better
+ * function just use it.
+ */
+ info->screen_base = memalign(fbsize, SZ_4M);
+ if (!info->screen_base)
+ return -ENOMEM;
+ memset(info->screen_base, 0, fbsize);
+ }
+ return 0;
+}
+
#ifdef CONFIG_IMXFB_DRIVER_VIDEO_IMX_OVERLAY
static void imxfb_overlay_enable_controller(struct fb_info *overlay)
{
@@ -455,11 +487,9 @@ static int imxfb_register_overlay(struct imxfb_info *fbi, void *fb)
overlay->bits_per_pixel = fbi->info.bits_per_pixel;
overlay->fbops = &imxfb_overlay_ops;
- if (fb)
- overlay->screen_base = fb;
- else
- overlay->screen_base = xzalloc(overlay->xres * overlay->yres *
- (overlay->bits_per_pixel >> 3));
+ ret = imxfb_allocate_fbbuffer(fbi->dev, overlay, fb);
+ if (ret < 0)
+ return ret;
writel((unsigned long)overlay->screen_base, fbi->regs + LCDC_LGWSAR);
writel(SIZE_XMAX(overlay->xres) | SIZE_YMAX(overlay->yres),
@@ -564,11 +594,10 @@ static int imxfb_probe(struct device_d *dev)
dev_info(dev, "i.MX Framebuffer driver\n");
- if (pdata->framebuffer)
- fbi->info.screen_base = pdata->framebuffer;
- else
- fbi->info.screen_base = xzalloc(info->xres * info->yres *
- (info->bits_per_pixel >> 3));
+
+ ret = imxfb_allocate_fbbuffer(dev, info, pdata->framebuffer);
+ if (ret < 0)
+ return ret;
imxfb_activate_var(&fbi->info);
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary
2015-09-16 20:00 [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary Uwe Kleine-König
@ 2015-09-17 6:10 ` Uwe Kleine-König
2015-09-21 6:09 ` Sascha Hauer
1 sibling, 0 replies; 3+ messages in thread
From: Uwe Kleine-König @ 2015-09-17 6:10 UTC (permalink / raw)
To: barebox
Hello
On Wed, Sep 16, 2015 at 10:00:44PM +0200, Uwe Kleine-König wrote:
> The reference manual (for the i.MX25 in my case) states:
>
> This field must start at a location that enables a complete
> picture to be stored in a 4 Mbyte memory boundary (A [21:0]). A
> [31:22] has a fixed value for a picture’s image.
>
> Check this condition for user-supplied framebuffer values and enforce it
> for driver-allocated buffers.
Maybe add here:
------>8------
If the buffer crosses a 4 MiB boundary the pixels that are "out of
bounds" just appear white on the display.
------>8------
I didn't check if the counter overflows and than picks up data from 4
MiB below the expected memory, but I would be surprised if I had only
0xff there.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary
2015-09-16 20:00 [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary Uwe Kleine-König
2015-09-17 6:10 ` Uwe Kleine-König
@ 2015-09-21 6:09 ` Sascha Hauer
1 sibling, 0 replies; 3+ messages in thread
From: Sascha Hauer @ 2015-09-21 6:09 UTC (permalink / raw)
To: Uwe Kleine-König; +Cc: barebox
On Wed, Sep 16, 2015 at 10:00:44PM +0200, Uwe Kleine-König wrote:
> The reference manual (for the i.MX25 in my case) states:
>
> This field must start at a location that enables a complete
> picture to be stored in a 4 Mbyte memory boundary (A [21:0]). A
> [31:22] has a fixed value for a picture’s image.
>
> Check this condition for user-supplied framebuffer values and enforce it
> for driver-allocated buffers.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Applied, thanks
Sascha
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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2015-09-16 20:00 [PATCH] video: imx: assert that image buffer doesn't cross a 4 MiB boundary Uwe Kleine-König
2015-09-17 6:10 ` Uwe Kleine-König
2015-09-21 6:09 ` Sascha Hauer
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