xref: /openbmc/linux/arch/ia64/pci/fixup.c (revision 9cfc5c90)
1 /*
2  * Exceptions for specific devices. Usually work-arounds for fatal design flaws.
3  * Derived from fixup.c of i386 tree.
4  */
5 
6 #include <linux/pci.h>
7 #include <linux/init.h>
8 #include <linux/vgaarb.h>
9 #include <linux/screen_info.h>
10 
11 #include <asm/machvec.h>
12 
13 /*
14  * Fixup to mark boot BIOS video selected by BIOS before it changes
15  *
16  * From information provided by "Jon Smirl" <jonsmirl@gmail.com>
17  *
18  * The standard boot ROM sequence for an x86 machine uses the BIOS
19  * to select an initial video card for boot display. This boot video
20  * card will have it's BIOS copied to C0000 in system RAM.
21  * IORESOURCE_ROM_SHADOW is used to associate the boot video
22  * card with this copy. On laptops this copy has to be used since
23  * the main ROM may be compressed or combined with another image.
24  * See pci_map_rom() for use of this flag. Before marking the device
25  * with IORESOURCE_ROM_SHADOW check if a vga_default_device is already set
26  * by either arch cde or vga-arbitration, if so only apply the fixup to this
27  * already determined primary video card.
28  */
29 
30 static void pci_fixup_video(struct pci_dev *pdev)
31 {
32 	struct pci_dev *bridge;
33 	struct pci_bus *bus;
34 	u16 config;
35 
36 	if ((strcmp(ia64_platform_name, "dig") != 0)
37 	    && (strcmp(ia64_platform_name, "hpzx1")  != 0))
38 		return;
39 	/* Maybe, this machine supports legacy memory map. */
40 
41 	/* Is VGA routed to us? */
42 	bus = pdev->bus;
43 	while (bus) {
44 		bridge = bus->self;
45 
46 		/*
47 		 * From information provided by
48 		 * "David Miller" <davem@davemloft.net>
49 		 * The bridge control register is valid for PCI header
50 		 * type BRIDGE, or CARDBUS. Host to PCI controllers use
51 		 * PCI header type NORMAL.
52 		 */
53 		if (bridge && (pci_is_bridge(bridge))) {
54 			pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
55 						&config);
56 			if (!(config & PCI_BRIDGE_CTL_VGA))
57 				return;
58 		}
59 		bus = bus->parent;
60 	}
61 	if (!vga_default_device() || pdev == vga_default_device()) {
62 		pci_read_config_word(pdev, PCI_COMMAND, &config);
63 		if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
64 			pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
65 			dev_printk(KERN_DEBUG, &pdev->dev, "Video device with shadowed ROM\n");
66 		}
67 	}
68 }
69 DECLARE_PCI_FIXUP_CLASS_FINAL(PCI_ANY_ID, PCI_ANY_ID,
70 				PCI_CLASS_DISPLAY_VGA, 8, pci_fixup_video);
71