x86: video: Support copy framebuffer with probed devices

For PCI video devices that are not mentioned in the devicetree, U-Boot
does not bind a driver before relocation, since PCI is not fully probed
at that point. Furthermore it is possible for the video device to be on
a secondary bus which is not even scanned.

This is fine if the framebuffer is allocated in fixed memory, as it
normally is on x86. But when using this as a copy framebuffer, we also
need U-Boot to allocate its own cached framebuffer for working in. Since
the video driver is never bound before relocation, the framebuffer size
is never set and U-Boot does no allocation.

Add a new CONFIG option to reserve 16MB of memory for this eventuality.
This allows vesa devices to use the copy framebuffer.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Tested-by: Bin Meng <bmeng.cn@gmail.com>

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 366e9ab4659097f4980db4a7ea567a42eb3675da..89ad603d886fe965db6210c5cd7b4e18abd86a05 100644 (file)
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -22,6 +22,25 @@ config BACKLIGHT
          This provides backlight uclass driver that enables basic panel
          backlight support.
 
+config VIDEO_PCI_DEFAULT_FB_SIZE
+       hex "Default framebuffer size to use if no drivers request it"
+       depends on DM_VIDEO
+       default 0x1000000 if X86 && PCI
+       default 0 if !(X86 && PCI)
+       help
+         Generally, video drivers request the amount of memory they need for
+         the frame buffer when they are bound, by setting the size field in
+         struct video_uc_platdata. That memory is then reserved for use after
+         relocation. But PCI drivers cannot be bound before relocation unless
+         they are mentioned in the devicetree.
+
+         With this value set appropriately, it is possible for PCI video
+         devices to have a framebuffer allocated by U-Boot.
+
+         Note: the framebuffer needs to be large enough to store all pixels at
+         maximum resolution. For example, at 1920 x 1200 with 32 bits per
+         pixel, 2560 * 1600 * 32 / 8 = 0xfa0000 bytes are needed.
+
 config VIDEO_COPY
        bool "Enable copying the frame buffer to a hardware copy"
        depends on DM_VIDEO

diff --git a/drivers/video/video-uclass.c b/drivers/video/video-uclass.c
index 4735a22dc11afb2e53dd50528390b7a4f7905e7b..650891e49dd0a0b334f3a5aac72b9a63ae4a5d87 100644 (file)
--- a/drivers/video/video-uclass.c
+++ b/drivers/video/video-uclass.c
@@ -97,6 +97,11 @@ int video_reserve(ulong *addrp)
                debug("%s: Reserving %lx bytes at %lx for video device '%s'\n",
                      __func__, size, *addrp, dev->name);
        }
+
+       /* Allocate space for PCI video devices in case there were not bound */
+       if (*addrp == gd->video_top)
+               *addrp -= CONFIG_VIDEO_PCI_DEFAULT_FB_SIZE;
+
        gd->video_bottom = *addrp;
        gd->fb_base = *addrp;
        debug("Video frame buffers from %lx to %lx\n", gd->video_bottom,