xref: /openbmc/linux/arch/ia64/pci/fixup.c (revision 206204a1)
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 
10 #include <asm/machvec.h>
11 
12 /*
13  * Fixup to mark boot BIOS video selected by BIOS before it changes
14  *
15  * From information provided by "Jon Smirl" <jonsmirl@gmail.com>
16  *
17  * The standard boot ROM sequence for an x86 machine uses the BIOS
18  * to select an initial video card for boot display. This boot video
19  * card will have it's BIOS copied to C0000 in system RAM.
20  * IORESOURCE_ROM_SHADOW is used to associate the boot video
21  * card with this copy. On laptops this copy has to be used since
22  * the main ROM may be compressed or combined with another image.
23  * See pci_map_rom() for use of this flag. Before marking the device
24  * with IORESOURCE_ROM_SHADOW check if a vga_default_device is already set
25  * by either arch cde or vga-arbitration, if so only apply the fixup to this
26  * already determined primary video card.
27  */
28 
29 static void pci_fixup_video(struct pci_dev *pdev)
30 {
31 	struct pci_dev *bridge;
32 	struct pci_bus *bus;
33 	u16 config;
34 
35 	if ((strcmp(ia64_platform_name, "dig") != 0)
36 	    && (strcmp(ia64_platform_name, "hpzx1")  != 0))
37 		return;
38 	/* Maybe, this machine supports legacy memory map. */
39 
40 	/* Is VGA routed to us? */
41 	bus = pdev->bus;
42 	while (bus) {
43 		bridge = bus->self;
44 
45 		/*
46 		 * From information provided by
47 		 * "David Miller" <davem@davemloft.net>
48 		 * The bridge control register is valid for PCI header
49 		 * type BRIDGE, or CARDBUS. Host to PCI controllers use
50 		 * PCI header type NORMAL.
51 		 */
52 		if (bridge && (pci_is_bridge(bridge))) {
53 			pci_read_config_word(bridge, PCI_BRIDGE_CONTROL,
54 						&config);
55 			if (!(config & PCI_BRIDGE_CTL_VGA))
56 				return;
57 		}
58 		bus = bus->parent;
59 	}
60 	if (!vga_default_device() || pdev == vga_default_device()) {
61 		pci_read_config_word(pdev, PCI_COMMAND, &config);
62 		if (config & (PCI_COMMAND_IO | PCI_COMMAND_MEMORY)) {
63 			pdev->resource[PCI_ROM_RESOURCE].flags |= IORESOURCE_ROM_SHADOW;
64 			dev_printk(KERN_DEBUG, &pdev->dev, "Boot video device\n");
65 			vga_set_default_device(pdev);
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