atmel_lcdfb: validate display timings
Setting a display timing parameter too high or too low may cause it to
wrap around and thus become completely wrong. Validate the timings in
atmel_lcdfb_check_var() and saturate to the highest or lowest possible
value if necessary.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/atmel_lcdfb.c b/drivers/video/atmel_lcdfb.c
index f8e7111..5d22ea5 100644
--- a/drivers/video/atmel_lcdfb.c
+++ b/drivers/video/atmel_lcdfb.c
@@ -203,6 +203,26 @@
var->transp.offset = var->transp.length = 0;
var->xoffset = var->yoffset = 0;
+ /* Saturate vertical and horizontal timings at maximum values */
+ var->vsync_len = min_t(u32, var->vsync_len,
+ (ATMEL_LCDC_VPW >> ATMEL_LCDC_VPW_OFFSET) + 1);
+ var->upper_margin = min_t(u32, var->upper_margin,
+ ATMEL_LCDC_VBP >> ATMEL_LCDC_VBP_OFFSET);
+ var->lower_margin = min_t(u32, var->lower_margin,
+ ATMEL_LCDC_VFP);
+ var->right_margin = min_t(u32, var->right_margin,
+ (ATMEL_LCDC_HFP >> ATMEL_LCDC_HFP_OFFSET) + 1);
+ var->hsync_len = min_t(u32, var->hsync_len,
+ (ATMEL_LCDC_HPW >> ATMEL_LCDC_HPW_OFFSET) + 1);
+ var->left_margin = min_t(u32, var->left_margin,
+ ATMEL_LCDC_HBP + 1);
+
+ /* Some parameters can't be zero */
+ var->vsync_len = max_t(u32, var->vsync_len, 1);
+ var->right_margin = max_t(u32, var->right_margin, 1);
+ var->hsync_len = max_t(u32, var->hsync_len, 1);
+ var->left_margin = max_t(u32, var->left_margin, 1);
+
switch (var->bits_per_pixel) {
case 1:
case 2: