PCI: Turn pci_fixup_video into generic for embedded VGA

pci_fixup_video turns into generic code because there are many platforms need this fixup
for embedded VGA as well as x86. The Video BIOS integrates into System BIOS on a machine
has embedded VGA although embedded VGA generally don't have PCI ROM. As a result,
embedded VGA need the way that the sysfs rom points to the Video BIOS of System
RAM (0xC0000). PCI-to-PCI Bridge Architecture specification describes the condition whether
or not PCI ROM forwards VGA compatible memory address. fixup_video suits this specification.
Although the Video ROM generally implements in x86 code regardless of platform, some
application such as X Window System can run this code by dosemu86. Therefore,
pci_fixup_video should turn into generic code.


Signed-off-by: Eiichiro Oiwa <eiichiro.oiwa.nm@hitachi.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Jesse Barnes <jesse.barnes@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 49 insertions, 1 deletions

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 1d2ccda946fd..371ab8821f10 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1619,6 +1619,51 @@ static void __devinit fixup_rev1_53c810(struct pci_dev* dev)
 }
 DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_NCR, PCI_DEVICE_ID_NCR_53C810, fixup_rev1_53c810);
 
+/*
+ * Fixup to mark boot BIOS video selected by BIOS before it changes
+ *
+ * From information provided by "Jon Smirl" <jonsmirl@gmail.com>
+ *
+ * The standard boot ROM sequence for an x86 machine uses the BIOS
+ * to select an initial video card for boot display. This boot video
+ * card will have it's BIOS copied to C0000 in system RAM.
+ * IORESOURCE_ROM_SHADOW is used to associate the boot video
+ * card with this copy. On laptops this copy has to be used since
+ * the main ROM may be compressed or combined with another image.
+ * See pci_map_rom() for use of this flag. IORESOURCE_ROM_SHADOW
+ * is marked here since the boot video device will be the only enabled
+ * video device at this point.
+ */
+
+static void __devinit fixup_video(struct pci_dev *pdev)
+{
+        struct pci_dev *bridge;
+        struct pci_bus *bus;
+        u16 config;
+
+        if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+                return;
+
+        /* Is VGA routed to us? */
+        bus = pdev->bus;
+        while (bus) {
+                bridge = bus->self;
+                if (bridge) {
+                        pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
+                                                &config);
+                        if (!(config & PCI_BRIDGE_CTL_VGA))
+                                return;
+                }
+                bus = bus->parent;
+        }
+        pci_read_config_word(pdev, PCI_COMMAND, &config);
+        if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
+                pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
+                printk(KERN_DEBUG "Boot video device is %s\n", pci_name(pdev));
+        }
+}
+DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, fixup_video);
+
 
 static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f, struct pci_fixup *end)
 {
diff --git a/drivers/pci/rom.c b/drivers/pci/rom.c
index f5ee7ce16fa6..43e4a49f2cc4 100644
--- a/drivers/pci/rom.c
+++ b/drivers/pci/rom.c
@@ -71,7 +71,10 @@ void __iomem *pci_map_rom(struct pci_dev *pdev, size_t *size)
         void __iomem *image;
         int last_image;
 
-        /* IORESOURCE_ROM_SHADOW only set on x86 */
+        /*
+         * IORESOURCE_ROM_SHADOW set if the VGA enable bit of the Bridge Control
+         * register is set for embedded VGA.
+         */
         if (res->flags & IORESOURCE_ROM_SHADOW) {
                 /* primary video rom always starts here */
                 start = (loff_t)0xC0000;