223 lines
6.8 KiB
C
223 lines
6.8 KiB
C
/* pci-frv.c: low-level PCI access routines
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*
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* Copyright (C) 2003-5 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* - Derived from the i386 equivalent stuff
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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-frv.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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resource_size_t size, resource_size_t align)
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{
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if (res->flags & IORESOURCE_IO) {
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resource_size_t 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 list_head *ln;
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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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for (ln=bus_list->next; ln != bus_list; ln=ln->next) {
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bus = pci_bus_b(ln);
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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->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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printk(KERN_ERR "PCI: Cannot allocate resource region %d of bridge %s\n", idx, pci_name(dev));
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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 void __init pcibios_assign_resources(void)
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{
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struct pci_dev *dev = NULL;
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int idx;
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struct resource *r;
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for_each_pci_dev(dev) {
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int class = dev->class >> 8;
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/* Don't touch classless devices and host bridges */
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if (!class || class == PCI_CLASS_BRIDGE_HOST)
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continue;
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for(idx=0; idx<6; idx++) {
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r = &dev->resource[idx];
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/*
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* Don't touch IDE controllers and I/O ports of video cards!
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*/
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if ((class == PCI_CLASS_STORAGE_IDE && idx < 4) ||
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(class == PCI_CLASS_DISPLAY_VGA && (r->flags & IORESOURCE_IO)))
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continue;
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/*
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* We shall assign a new address to this resource, either because
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* the BIOS forgot to do so or because we have decided the old
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* address was unusable for some reason.
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*/
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if (!r->start && r->end)
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pci_assign_resource(dev, idx);
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}
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if (pci_probe & PCI_ASSIGN_ROMS) {
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r = &dev->resource[PCI_ROM_RESOURCE];
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r->end -= r->start;
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r->start = 0;
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if (r->end)
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pci_assign_resource(dev, PCI_ROM_RESOURCE);
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}
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}
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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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pcibios_assign_resources();
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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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