316 lines
6.4 KiB
C
316 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* direct.c - Low-level direct PCI config space access
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*/
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#include <linux/pci.h>
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#include <linux/init.h>
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#include <linux/dmi.h>
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#include <asm/pci_x86.h>
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/*
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* Functions for accessing PCI base (first 256 bytes) and extended
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* (4096 bytes per PCI function) configuration space with type 1
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* accesses.
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*/
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#define PCI_CONF1_ADDRESS(bus, devfn, reg) \
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(0x80000000 | ((reg & 0xF00) << 16) | (bus << 16) \
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| (devfn << 8) | (reg & 0xFC))
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static int pci_conf1_read(unsigned int seg, unsigned int bus,
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unsigned int devfn, int reg, int len, u32 *value)
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{
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unsigned long flags;
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if (seg || (bus > 255) || (devfn > 255) || (reg > 4095)) {
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*value = -1;
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return -EINVAL;
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}
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raw_spin_lock_irqsave(&pci_config_lock, flags);
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outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
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switch (len) {
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case 1:
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*value = inb(0xCFC + (reg & 3));
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break;
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case 2:
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*value = inw(0xCFC + (reg & 2));
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break;
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case 4:
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*value = inl(0xCFC);
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break;
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}
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return 0;
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}
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static int pci_conf1_write(unsigned int seg, unsigned int bus,
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unsigned int devfn, int reg, int len, u32 value)
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{
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unsigned long flags;
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if (seg || (bus > 255) || (devfn > 255) || (reg > 4095))
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return -EINVAL;
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raw_spin_lock_irqsave(&pci_config_lock, flags);
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outl(PCI_CONF1_ADDRESS(bus, devfn, reg), 0xCF8);
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switch (len) {
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case 1:
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outb((u8)value, 0xCFC + (reg & 3));
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break;
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case 2:
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outw((u16)value, 0xCFC + (reg & 2));
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break;
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case 4:
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outl((u32)value, 0xCFC);
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break;
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}
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return 0;
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}
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#undef PCI_CONF1_ADDRESS
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const struct pci_raw_ops pci_direct_conf1 = {
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.read = pci_conf1_read,
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.write = pci_conf1_write,
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};
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/*
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* Functions for accessing PCI configuration space with type 2 accesses
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*/
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#define PCI_CONF2_ADDRESS(dev, reg) (u16)(0xC000 | (dev << 8) | reg)
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static int pci_conf2_read(unsigned int seg, unsigned int bus,
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unsigned int devfn, int reg, int len, u32 *value)
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{
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unsigned long flags;
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int dev, fn;
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WARN_ON(seg);
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if ((bus > 255) || (devfn > 255) || (reg > 255)) {
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*value = -1;
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return -EINVAL;
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}
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dev = PCI_SLOT(devfn);
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fn = PCI_FUNC(devfn);
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if (dev & 0x10)
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return PCIBIOS_DEVICE_NOT_FOUND;
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raw_spin_lock_irqsave(&pci_config_lock, flags);
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outb((u8)(0xF0 | (fn << 1)), 0xCF8);
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outb((u8)bus, 0xCFA);
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switch (len) {
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case 1:
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*value = inb(PCI_CONF2_ADDRESS(dev, reg));
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break;
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case 2:
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*value = inw(PCI_CONF2_ADDRESS(dev, reg));
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break;
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case 4:
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*value = inl(PCI_CONF2_ADDRESS(dev, reg));
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break;
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}
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outb(0, 0xCF8);
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return 0;
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}
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static int pci_conf2_write(unsigned int seg, unsigned int bus,
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unsigned int devfn, int reg, int len, u32 value)
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{
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unsigned long flags;
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int dev, fn;
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WARN_ON(seg);
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if ((bus > 255) || (devfn > 255) || (reg > 255))
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return -EINVAL;
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dev = PCI_SLOT(devfn);
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fn = PCI_FUNC(devfn);
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if (dev & 0x10)
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return PCIBIOS_DEVICE_NOT_FOUND;
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raw_spin_lock_irqsave(&pci_config_lock, flags);
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outb((u8)(0xF0 | (fn << 1)), 0xCF8);
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outb((u8)bus, 0xCFA);
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switch (len) {
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case 1:
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outb((u8)value, PCI_CONF2_ADDRESS(dev, reg));
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break;
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case 2:
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outw((u16)value, PCI_CONF2_ADDRESS(dev, reg));
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break;
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case 4:
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outl((u32)value, PCI_CONF2_ADDRESS(dev, reg));
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break;
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}
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outb(0, 0xCF8);
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return 0;
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}
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#undef PCI_CONF2_ADDRESS
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static const struct pci_raw_ops pci_direct_conf2 = {
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.read = pci_conf2_read,
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.write = pci_conf2_write,
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};
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/*
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* Before we decide to use direct hardware access mechanisms, we try to do some
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* trivial checks to ensure it at least _seems_ to be working -- we just test
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* whether bus 00 contains a host bridge (this is similar to checking
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* techniques used in XFree86, but ours should be more reliable since we
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* attempt to make use of direct access hints provided by the PCI BIOS).
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*
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* This should be close to trivial, but it isn't, because there are buggy
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* chipsets (yes, you guessed it, by Intel and Compaq) that have no class ID.
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*/
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static int __init pci_sanity_check(const struct pci_raw_ops *o)
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{
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u32 x = 0;
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int devfn;
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if (pci_probe & PCI_NO_CHECKS)
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return 1;
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/* Assume Type 1 works for newer systems.
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This handles machines that don't have anything on PCI Bus 0. */
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if (dmi_get_bios_year() >= 2001)
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return 1;
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for (devfn = 0; devfn < 0x100; devfn++) {
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if (o->read(0, 0, devfn, PCI_CLASS_DEVICE, 2, &x))
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continue;
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if (x == PCI_CLASS_BRIDGE_HOST || x == PCI_CLASS_DISPLAY_VGA)
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return 1;
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if (o->read(0, 0, devfn, PCI_VENDOR_ID, 2, &x))
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continue;
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if (x == PCI_VENDOR_ID_INTEL || x == PCI_VENDOR_ID_COMPAQ)
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return 1;
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}
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DBG(KERN_WARNING "PCI: Sanity check failed\n");
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return 0;
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}
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static int __init pci_check_type1(void)
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{
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unsigned long flags;
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unsigned int tmp;
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int works = 0;
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local_irq_save(flags);
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outb(0x01, 0xCFB);
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tmp = inl(0xCF8);
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outl(0x80000000, 0xCF8);
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if (inl(0xCF8) == 0x80000000 && pci_sanity_check(&pci_direct_conf1)) {
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works = 1;
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}
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outl(tmp, 0xCF8);
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local_irq_restore(flags);
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return works;
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}
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static int __init pci_check_type2(void)
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{
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unsigned long flags;
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int works = 0;
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local_irq_save(flags);
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outb(0x00, 0xCFB);
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outb(0x00, 0xCF8);
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outb(0x00, 0xCFA);
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if (inb(0xCF8) == 0x00 && inb(0xCFA) == 0x00 &&
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pci_sanity_check(&pci_direct_conf2)) {
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works = 1;
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}
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local_irq_restore(flags);
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return works;
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}
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void __init pci_direct_init(int type)
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{
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if (type == 0)
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return;
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printk(KERN_INFO "PCI: Using configuration type %d for base access\n",
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type);
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if (type == 1) {
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raw_pci_ops = &pci_direct_conf1;
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if (raw_pci_ext_ops)
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return;
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if (!(pci_probe & PCI_HAS_IO_ECS))
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return;
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printk(KERN_INFO "PCI: Using configuration type 1 "
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"for extended access\n");
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raw_pci_ext_ops = &pci_direct_conf1;
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return;
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}
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raw_pci_ops = &pci_direct_conf2;
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}
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int __init pci_direct_probe(void)
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{
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if ((pci_probe & PCI_PROBE_CONF1) == 0)
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goto type2;
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if (!request_region(0xCF8, 8, "PCI conf1"))
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goto type2;
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if (pci_check_type1()) {
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raw_pci_ops = &pci_direct_conf1;
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port_cf9_safe = true;
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return 1;
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}
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release_region(0xCF8, 8);
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type2:
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if ((pci_probe & PCI_PROBE_CONF2) == 0)
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return 0;
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if (!request_region(0xCF8, 4, "PCI conf2"))
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return 0;
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if (!request_region(0xC000, 0x1000, "PCI conf2"))
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goto fail2;
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if (pci_check_type2()) {
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raw_pci_ops = &pci_direct_conf2;
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port_cf9_safe = true;
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return 2;
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}
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release_region(0xC000, 0x1000);
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fail2:
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release_region(0xCF8, 4);
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return 0;
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}
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