From 067b226b9e8e20463e0937344c93101ac8d8d2b1 Mon Sep 17 00:00:00 2001 From: Pawel Osciak Date: Tue, 10 Aug 2010 18:02:38 -0700 Subject: s3c-fb: add support for display panning Supports all bpp modes. The PRTCON register is used to disable in-hardware updates of registers that store start and end addresses of framebuffer memory. This prevents display corruption in case we do not make it before VSYNC with updating them atomically. With this feature there is no need to wait for a VSYNC interrupt before each such update. Signed-off-by: Pawel Osciak Signed-off-by: Kyungmin Park Cc: InKi Dae Cc: Ben Dooks Cc: Marek Szyprowski Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/s3c-fb.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) (limited to 'drivers/video/s3c-fb.c') 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], -- cgit v1.2.1