2 files changed, 75 insertions, 0 deletions

diff --git a/arch/arm/plat-samsung/include/plat/regs-fb.h b/arch/arm/plat-samsung/include/plat/regs-fb.h
index ac10013959bd..dbb6c0afef47 100644
--- a/arch/arm/plat-samsung/include/plat/regs-fb.h
+++ b/arch/arm/plat-samsung/include/plat/regs-fb.h
@@ -112,6 +112,13 @@
 #define VIDCON2_ORGYCbCr                        (1 << 8)
 #define VIDCON2_YUVORDCrCb                      (1 << 7)
 
+/* PRTCON (S3C6410, S5PC100)
+ * Might not be present in the S3C6410 documentation,
+ * but tests prove it's there almost for sure; shouldn't hurt in any case.
+ */
+#define PRTCON                                  (0x0c)
+#define PRTCON_PROTECT                          (1 << 11)
+
 /* VIDTCON0 */
 
 #define VIDTCON0_VBPDE_MASK                     (0xff << 24)
diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
index 5f931b4933bd..de427d928f48 100644
--- a/drivers/video/s3c-fb.c
+++ b/drivers/video/s3c-fb.c
@@ -71,6 +71,7 @@ struct s3c_fb;
  * @buf_end: Offset of buffer end registers.
  * @osd: The base for the OSD registers.
  * @palette: Address of palette memory, or 0 if none.
+ * @has_prtcon: Set if has PRTCON register.
  */
 struct s3c_fb_variant {
         unsigned int    is_2443:1;
@@ -85,6 +86,8 @@ struct s3c_fb_variant {
         unsigned short  osd;
         unsigned short  osd_stride;
         unsigned short  palette[S3C_FB_MAX_WIN];
+
+        unsigned int    has_prtcon:1;
 };
 
 /**
@@ -379,6 +382,9 @@ static int s3c_fb_set_par(struct fb_info *info)
 
         info->fix.line_length = (var->xres_virtual * var->bits_per_pixel) / 8;
 
+        info->fix.xpanstep = info->var.xres_virtual > info->var.xres ? 1 : 0;
+        info->fix.ypanstep = info->var.yres_virtual > info->var.yres ? 1 : 0;
+
         /* disable the window whilst we update it */
         writel(0, regs + WINCON(win_no));
 
@@ -735,6 +741,63 @@ static int s3c_fb_blank(int blank_mode, struct fb_info *info)
         return 0;
 }
 
+/**
+ * s3c_fb_pan_display() - Pan the display.
+ *
+ * Note that the offsets can be written to the device at any time, as their
+ * values are latched at each vsync automatically. This also means that only
+ * the last call to this function will have any effect on next vsync, but
+ * there is no need to sleep waiting for it to prevent tearing.
+ *
+ * @var: The screen information to verify.
+ * @info: The framebuffer device.
+ */
+static int s3c_fb_pan_display(struct fb_var_screeninfo *var,
+                              struct fb_info *info)
+{
+        struct s3c_fb_win *win  = info->par;
+        struct s3c_fb *sfb      = win->parent;
+        void __iomem *buf       = sfb->regs + win->index * 8;
+        unsigned int start_boff, end_boff;
+
+        /* Offset in bytes to the start of the displayed area */
+        start_boff = var->yoffset * info->fix.line_length;
+        /* X offset depends on the current bpp */
+        if (info->var.bits_per_pixel >= 8) {
+                start_boff += var->xoffset * (info->var.bits_per_pixel >> 3);
+        } else {
+                switch (info->var.bits_per_pixel) {
+                case 4:
+                        start_boff += var->xoffset >> 1;
+                        break;
+                case 2:
+                        start_boff += var->xoffset >> 2;
+                        break;
+                case 1:
+                        start_boff += var->xoffset >> 3;
+                        break;
+                default:
+                        dev_err(sfb->dev, "invalid bpp\n");
+                        return -EINVAL;
+                }
+        }
+        /* Offset in bytes to the end of the displayed area */
+        end_boff = start_boff + var->yres * info->fix.line_length;
+
+        /* Temporarily turn off per-vsync update from shadow registers until
+         * both start and end addresses are updated to prevent corruption */
+        if (sfb->variant.has_prtcon)
+                writel(PRTCON_PROTECT, sfb->regs + PRTCON);
+
+        writel(info->fix.smem_start + start_boff, buf + sfb->variant.buf_start);
+        writel(info->fix.smem_start + end_boff, buf + sfb->variant.buf_end);
+
+        if (sfb->variant.has_prtcon)
+                writel(0, sfb->regs + PRTCON);
+
+        return 0;
+}
+
 static struct fb_ops s3c_fb_ops = {
         .owner          = THIS_MODULE,
         .fb_check_var   = s3c_fb_check_var,
@@ -744,6 +807,7 @@ static struct fb_ops s3c_fb_ops = {
         .fb_fillrect    = cfb_fillrect,
         .fb_copyarea    = cfb_copyarea,
         .fb_imageblit   = cfb_imageblit,
+        .fb_pan_display = s3c_fb_pan_display,
 };
 
 /**
@@ -1243,6 +1307,8 @@ static struct s3c_fb_driverdata s3c_fb_data_64xx __devinitdata = {
                         [3] = 0x320,
                         [4] = 0x340,
                 },
+
+                .has_prtcon     = 1,
         },
         .win[0] = &s3c_fb_data_64xx_wins[0],
         .win[1] = &s3c_fb_data_64xx_wins[1],
@@ -1271,6 +1337,8 @@ static struct s3c_fb_driverdata s3c_fb_data_s5pc100 __devinitdata = {
                         [3] = 0x3000,
                         [4] = 0x3400,
                 },
+
+                .has_prtcon     = 1,
         },
         .win[0] = &s3c_fb_data_64xx_wins[0],
         .win[1] = &s3c_fb_data_64xx_wins[1],