![Rajesh Shah](/assets/img/avatar_default.png)
When attempting to hotadd a PCI card with a bridge on it, I saw the kernel reporting resource collision errors even when there were really no collisions. The problem is that the code doesn't skip over "invalid" resources with their resource type flag not set. Others have reported similar problems at boot time and for non-bridge PCI card hotplug too, where the code flags a resource collision for disabled ROMs. This patch fixes both problems. Signed-off-by: Rajesh Shah <rajesh.shah@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
296 lines
8.6 KiB
C
296 lines
8.6 KiB
C
/*
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* Low-Level PCI Access for i386 machines
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*
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* Copyright 1993, 1994 Drew Eckhardt
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* Visionary Computing
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* (Unix and Linux consulting and custom programming)
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* Drew@Colorado.EDU
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* +1 (303) 786-7975
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*
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* Drew's work was sponsored by:
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* iX Multiuser Multitasking Magazine
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* Hannover, Germany
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* hm@ix.de
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*
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* Copyright 1997--2000 Martin Mares <mj@ucw.cz>
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*
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* For more information, please consult the following manuals (look at
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* http://www.pcisig.com/ for how to get them):
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*
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* PCI BIOS Specification
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* PCI Local Bus Specification
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* PCI to PCI Bridge Specification
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* PCI System Design Guide
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*
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/pci.h>
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#include <linux/init.h>
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#include <linux/ioport.h>
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#include <linux/errno.h>
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#include "pci.h"
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/*
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* We need to avoid collisions with `mirrored' VGA ports
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* and other strange ISA hardware, so we always want the
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* addresses to be allocated in the 0x000-0x0ff region
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* modulo 0x400.
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*
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* Why? Because some silly external IO cards only decode
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* the low 10 bits of the IO address. The 0x00-0xff region
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* is reserved for motherboard devices that decode all 16
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* bits, so it's ok to allocate at, say, 0x2800-0x28ff,
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* but we want to try to avoid allocating at 0x2900-0x2bff
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* which might have be mirrored at 0x0100-0x03ff..
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*/
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void
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pcibios_align_resource(void *data, struct resource *res,
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unsigned long size, unsigned long align)
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{
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if (res->flags & IORESOURCE_IO) {
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unsigned long start = res->start;
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if (start & 0x300) {
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start = (start + 0x3ff) & ~0x3ff;
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res->start = start;
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}
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}
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}
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/*
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* Handle resources of PCI devices. If the world were perfect, we could
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* just allocate all the resource regions and do nothing more. It isn't.
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* On the other hand, we cannot just re-allocate all devices, as it would
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* require us to know lots of host bridge internals. So we attempt to
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* keep as much of the original configuration as possible, but tweak it
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* when it's found to be wrong.
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*
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* Known BIOS problems we have to work around:
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* - I/O or memory regions not configured
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* - regions configured, but not enabled in the command register
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* - bogus I/O addresses above 64K used
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* - expansion ROMs left enabled (this may sound harmless, but given
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* the fact the PCI specs explicitly allow address decoders to be
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* shared between expansion ROMs and other resource regions, it's
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* at least dangerous)
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*
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* Our solution:
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* (1) Allocate resources for all buses behind PCI-to-PCI bridges.
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* This gives us fixed barriers on where we can allocate.
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* (2) Allocate resources for all enabled devices. If there is
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* a collision, just mark the resource as unallocated. Also
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* disable expansion ROMs during this step.
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* (3) Try to allocate resources for disabled devices. If the
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* resources were assigned correctly, everything goes well,
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* if they weren't, they won't disturb allocation of other
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* resources.
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* (4) Assign new addresses to resources which were either
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* not configured at all or misconfigured. If explicitly
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* requested by the user, configure expansion ROM address
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* as well.
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*/
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static void __init pcibios_allocate_bus_resources(struct list_head *bus_list)
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{
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struct pci_bus *bus;
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struct pci_dev *dev;
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int idx;
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struct resource *r, *pr;
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/* Depth-First Search on bus tree */
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list_for_each_entry(bus, bus_list, node) {
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if ((dev = bus->self)) {
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for (idx = PCI_BRIDGE_RESOURCES; idx < PCI_NUM_RESOURCES; idx++) {
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r = &dev->resource[idx];
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if (!r->flags)
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continue;
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pr = pci_find_parent_resource(dev, r);
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if (!r->start || !pr || request_resource(pr, r) < 0) {
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printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, pci_name(dev));
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/* Something is wrong with the region.
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Invalidate the resource to prevent child
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resource allocations in this range. */
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r->flags = 0;
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}
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}
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}
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pcibios_allocate_bus_resources(&bus->children);
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}
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}
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static void __init pcibios_allocate_resources(int pass)
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{
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struct pci_dev *dev = NULL;
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int idx, disabled;
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u16 command;
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struct resource *r, *pr;
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for_each_pci_dev(dev) {
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pci_read_config_word(dev, PCI_COMMAND, &command);
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for(idx = 0; idx < 6; idx++) {
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r = &dev->resource[idx];
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if (r->parent) /* Already allocated */
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continue;
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if (!r->start) /* Address not assigned at all */
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continue;
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if (r->flags & IORESOURCE_IO)
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disabled = !(command & PCI_COMMAND_IO);
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else
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disabled = !(command & PCI_COMMAND_MEMORY);
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if (pass == disabled) {
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DBG("PCI: Resource %08lx-%08lx (f=%lx, d=%d, p=%d)\n",
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r->start, r->end, r->flags, disabled, pass);
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pr = pci_find_parent_resource(dev, r);
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if (!pr || request_resource(pr, r) < 0) {
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printk(KERN_ERR "PCI: Cannot allocate resource region %d of device %s\n", idx, pci_name(dev));
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/* We'll assign a new address later */
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r->end -= r->start;
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r->start = 0;
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}
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}
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}
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if (!pass) {
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r = &dev->resource[PCI_ROM_RESOURCE];
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if (r->flags & IORESOURCE_ROM_ENABLE) {
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/* Turn the ROM off, leave the resource region, but keep it unregistered. */
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u32 reg;
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DBG("PCI: Switching off ROM of %s\n", pci_name(dev));
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r->flags &= ~IORESOURCE_ROM_ENABLE;
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pci_read_config_dword(dev, dev->rom_base_reg, ®);
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pci_write_config_dword(dev, dev->rom_base_reg, reg & ~PCI_ROM_ADDRESS_ENABLE);
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}
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}
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}
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}
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static int __init pcibios_assign_resources(void)
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{
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struct pci_dev *dev = NULL;
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struct resource *r, *pr;
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if (!(pci_probe & PCI_ASSIGN_ROMS)) {
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/* Try to use BIOS settings for ROMs, otherwise let
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pci_assign_unassigned_resources() allocate the new
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addresses. */
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for_each_pci_dev(dev) {
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r = &dev->resource[PCI_ROM_RESOURCE];
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if (!r->flags || !r->start)
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continue;
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pr = pci_find_parent_resource(dev, r);
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if (!pr || request_resource(pr, r) < 0) {
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r->end -= r->start;
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r->start = 0;
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}
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}
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}
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pci_assign_unassigned_resources();
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return 0;
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}
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void __init pcibios_resource_survey(void)
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{
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DBG("PCI: Allocating resources\n");
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pcibios_allocate_bus_resources(&pci_root_buses);
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pcibios_allocate_resources(0);
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pcibios_allocate_resources(1);
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}
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/**
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* called in fs_initcall (one below subsys_initcall),
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* give a chance for motherboard reserve resources
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*/
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fs_initcall(pcibios_assign_resources);
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int pcibios_enable_resources(struct pci_dev *dev, int mask)
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{
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u16 cmd, old_cmd;
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int idx;
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struct resource *r;
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pci_read_config_word(dev, PCI_COMMAND, &cmd);
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old_cmd = cmd;
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for(idx = 0; idx < PCI_NUM_RESOURCES; idx++) {
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/* Only set up the requested stuff */
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if (!(mask & (1<<idx)))
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continue;
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r = &dev->resource[idx];
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if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM)))
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continue;
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if ((idx == PCI_ROM_RESOURCE) &&
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(!(r->flags & IORESOURCE_ROM_ENABLE)))
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continue;
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if (!r->start && r->end) {
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printk(KERN_ERR "PCI: Device %s not available because of resource collisions\n", pci_name(dev));
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return -EINVAL;
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}
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if (r->flags & IORESOURCE_IO)
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cmd |= PCI_COMMAND_IO;
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if (r->flags & IORESOURCE_MEM)
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cmd |= PCI_COMMAND_MEMORY;
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}
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if (cmd != old_cmd) {
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printk("PCI: Enabling device %s (%04x -> %04x)\n", pci_name(dev), old_cmd, cmd);
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pci_write_config_word(dev, PCI_COMMAND, cmd);
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}
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return 0;
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}
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/*
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* If we set up a device for bus mastering, we need to check the latency
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* timer as certain crappy BIOSes forget to set it properly.
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*/
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unsigned int pcibios_max_latency = 255;
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void pcibios_set_master(struct pci_dev *dev)
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{
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u8 lat;
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pci_read_config_byte(dev, PCI_LATENCY_TIMER, &lat);
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if (lat < 16)
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lat = (64 <= pcibios_max_latency) ? 64 : pcibios_max_latency;
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else if (lat > pcibios_max_latency)
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lat = pcibios_max_latency;
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else
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return;
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printk(KERN_DEBUG "PCI: Setting latency timer of device %s to %d\n", pci_name(dev), lat);
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pci_write_config_byte(dev, PCI_LATENCY_TIMER, lat);
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}
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int pci_mmap_page_range(struct pci_dev *dev, struct vm_area_struct *vma,
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enum pci_mmap_state mmap_state, int write_combine)
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{
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unsigned long prot;
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/* I/O space cannot be accessed via normal processor loads and
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* stores on this platform.
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*/
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if (mmap_state == pci_mmap_io)
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return -EINVAL;
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/* Leave vm_pgoff as-is, the PCI space address is the physical
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* address on this platform.
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*/
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vma->vm_flags |= (VM_SHM | VM_LOCKED | VM_IO);
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prot = pgprot_val(vma->vm_page_prot);
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if (boot_cpu_data.x86 > 3)
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prot |= _PAGE_PCD | _PAGE_PWT;
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vma->vm_page_prot = __pgprot(prot);
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/* Write-combine setting is ignored, it is changed via the mtrr
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* interfaces on this platform.
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*/
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if (io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
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vma->vm_end - vma->vm_start,
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vma->vm_page_prot))
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return -EAGAIN;
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return 0;
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}
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