430 lines
10 KiB
C
430 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* BIOS32 and PCI BIOS handling.
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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/slab.h>
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#include <linux/module.h>
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#include <linux/uaccess.h>
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#include <asm/pci_x86.h>
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#include <asm/e820/types.h>
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#include <asm/pci-functions.h>
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#include <asm/set_memory.h>
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/* BIOS32 signature: "_32_" */
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#define BIOS32_SIGNATURE (('_' << 0) + ('3' << 8) + ('2' << 16) + ('_' << 24))
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/* PCI signature: "PCI " */
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#define PCI_SIGNATURE (('P' << 0) + ('C' << 8) + ('I' << 16) + (' ' << 24))
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/* PCI service signature: "$PCI" */
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#define PCI_SERVICE (('$' << 0) + ('P' << 8) + ('C' << 16) + ('I' << 24))
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/* PCI BIOS hardware mechanism flags */
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#define PCIBIOS_HW_TYPE1 0x01
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#define PCIBIOS_HW_TYPE2 0x02
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#define PCIBIOS_HW_TYPE1_SPEC 0x10
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#define PCIBIOS_HW_TYPE2_SPEC 0x20
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int pcibios_enabled;
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/* According to the BIOS specification at:
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* http://members.datafast.net.au/dft0802/specs/bios21.pdf, we could
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* restrict the x zone to some pages and make it ro. But this may be
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* broken on some bios, complex to handle with static_protections.
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* We could make the 0xe0000-0x100000 range rox, but this can break
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* some ISA mapping.
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*
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* So we let's an rw and x hole when pcibios is used. This shouldn't
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* happen for modern system with mmconfig, and if you don't want it
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* you could disable pcibios...
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*/
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static inline void set_bios_x(void)
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{
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pcibios_enabled = 1;
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set_memory_x(PAGE_OFFSET + BIOS_BEGIN, (BIOS_END - BIOS_BEGIN) >> PAGE_SHIFT);
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if (__supported_pte_mask & _PAGE_NX)
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printk(KERN_INFO "PCI: PCI BIOS area is rw and x. Use pci=nobios if you want it NX.\n");
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}
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/*
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* This is the standard structure used to identify the entry point
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* to the BIOS32 Service Directory, as documented in
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* Standard BIOS 32-bit Service Directory Proposal
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* Revision 0.4 May 24, 1993
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* Phoenix Technologies Ltd.
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* Norwood, MA
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* and the PCI BIOS specification.
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*/
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union bios32 {
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struct {
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unsigned long signature; /* _32_ */
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unsigned long entry; /* 32 bit physical address */
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unsigned char revision; /* Revision level, 0 */
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unsigned char length; /* Length in paragraphs should be 01 */
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unsigned char checksum; /* All bytes must add up to zero */
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unsigned char reserved[5]; /* Must be zero */
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} fields;
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char chars[16];
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};
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/*
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* Physical address of the service directory. I don't know if we're
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* allowed to have more than one of these or not, so just in case
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* we'll make pcibios_present() take a memory start parameter and store
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* the array there.
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*/
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static struct {
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unsigned long address;
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unsigned short segment;
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} bios32_indirect __initdata = { 0, __KERNEL_CS };
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/*
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* Returns the entry point for the given service, NULL on error
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*/
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static unsigned long __init bios32_service(unsigned long service)
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{
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unsigned char return_code; /* %al */
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unsigned long address; /* %ebx */
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unsigned long length; /* %ecx */
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unsigned long entry; /* %edx */
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unsigned long flags;
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local_irq_save(flags);
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__asm__("lcall *(%%edi); cld"
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: "=a" (return_code),
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"=b" (address),
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"=c" (length),
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"=d" (entry)
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: "0" (service),
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"1" (0),
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"D" (&bios32_indirect));
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local_irq_restore(flags);
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switch (return_code) {
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case 0:
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return address + entry;
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case 0x80: /* Not present */
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printk(KERN_WARNING "bios32_service(0x%lx): not present\n", service);
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return 0;
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default: /* Shouldn't happen */
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printk(KERN_WARNING "bios32_service(0x%lx): returned 0x%x -- BIOS bug!\n",
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service, return_code);
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return 0;
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}
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}
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static struct {
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unsigned long address;
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unsigned short segment;
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} pci_indirect __ro_after_init = {
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.address = 0,
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.segment = __KERNEL_CS,
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};
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static int pci_bios_present __ro_after_init;
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static int __init check_pcibios(void)
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{
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u32 signature, eax, ebx, ecx;
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u8 status, major_ver, minor_ver, hw_mech;
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unsigned long flags, pcibios_entry;
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if ((pcibios_entry = bios32_service(PCI_SERVICE))) {
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pci_indirect.address = pcibios_entry + PAGE_OFFSET;
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local_irq_save(flags);
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__asm__(
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"lcall *(%%edi); cld\n\t"
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"jc 1f\n\t"
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"xor %%ah, %%ah\n"
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"1:"
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: "=d" (signature),
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"=a" (eax),
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"=b" (ebx),
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"=c" (ecx)
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: "1" (PCIBIOS_PCI_BIOS_PRESENT),
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"D" (&pci_indirect)
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: "memory");
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local_irq_restore(flags);
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status = (eax >> 8) & 0xff;
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hw_mech = eax & 0xff;
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major_ver = (ebx >> 8) & 0xff;
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minor_ver = ebx & 0xff;
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if (pcibios_last_bus < 0)
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pcibios_last_bus = ecx & 0xff;
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DBG("PCI: BIOS probe returned s=%02x hw=%02x ver=%02x.%02x l=%02x\n",
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status, hw_mech, major_ver, minor_ver, pcibios_last_bus);
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if (status || signature != PCI_SIGNATURE) {
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printk (KERN_ERR "PCI: BIOS BUG #%x[%08x] found\n",
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status, signature);
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return 0;
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}
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printk(KERN_INFO "PCI: PCI BIOS revision %x.%02x entry at 0x%lx, last bus=%d\n",
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major_ver, minor_ver, pcibios_entry, pcibios_last_bus);
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#ifdef CONFIG_PCI_DIRECT
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if (!(hw_mech & PCIBIOS_HW_TYPE1))
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pci_probe &= ~PCI_PROBE_CONF1;
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if (!(hw_mech & PCIBIOS_HW_TYPE2))
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pci_probe &= ~PCI_PROBE_CONF2;
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#endif
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return 1;
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}
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return 0;
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}
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static int pci_bios_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 result = 0;
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unsigned long flags;
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unsigned long bx = (bus << 8) | devfn;
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u16 number = 0, mask = 0;
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WARN_ON(seg);
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if (!value || (bus > 255) || (devfn > 255) || (reg > 255))
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return -EINVAL;
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raw_spin_lock_irqsave(&pci_config_lock, flags);
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switch (len) {
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case 1:
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number = PCIBIOS_READ_CONFIG_BYTE;
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mask = 0xff;
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break;
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case 2:
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number = PCIBIOS_READ_CONFIG_WORD;
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mask = 0xffff;
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break;
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case 4:
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number = PCIBIOS_READ_CONFIG_DWORD;
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break;
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}
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__asm__("lcall *(%%esi); cld\n\t"
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"jc 1f\n\t"
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"xor %%ah, %%ah\n"
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"1:"
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: "=c" (*value),
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"=a" (result)
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: "1" (number),
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"b" (bx),
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"D" ((long)reg),
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"S" (&pci_indirect));
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/*
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* Zero-extend the result beyond 8 or 16 bits, do not trust the
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* BIOS having done it:
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*/
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if (mask)
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*value &= mask;
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return (int)((result & 0xff00) >> 8);
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}
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static int pci_bios_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 result = 0;
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unsigned long flags;
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unsigned long bx = (bus << 8) | devfn;
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u16 number = 0;
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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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raw_spin_lock_irqsave(&pci_config_lock, flags);
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switch (len) {
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case 1:
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number = PCIBIOS_WRITE_CONFIG_BYTE;
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break;
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case 2:
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number = PCIBIOS_WRITE_CONFIG_WORD;
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break;
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case 4:
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number = PCIBIOS_WRITE_CONFIG_DWORD;
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break;
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}
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__asm__("lcall *(%%esi); cld\n\t"
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"jc 1f\n\t"
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"xor %%ah, %%ah\n"
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"1:"
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: "=a" (result)
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: "0" (number),
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"c" (value),
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"b" (bx),
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"D" ((long)reg),
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"S" (&pci_indirect));
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raw_spin_unlock_irqrestore(&pci_config_lock, flags);
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return (int)((result & 0xff00) >> 8);
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}
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/*
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* Function table for BIOS32 access
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*/
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static const struct pci_raw_ops pci_bios_access = {
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.read = pci_bios_read,
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.write = pci_bios_write
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};
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/*
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* Try to find PCI BIOS.
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*/
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static const struct pci_raw_ops *__init pci_find_bios(void)
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{
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union bios32 *check;
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unsigned char sum;
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int i, length;
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/*
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* Follow the standard procedure for locating the BIOS32 Service
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* directory by scanning the permissible address range from
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* 0xe0000 through 0xfffff for a valid BIOS32 structure.
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*/
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for (check = (union bios32 *) __va(0xe0000);
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check <= (union bios32 *) __va(0xffff0);
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++check) {
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long sig;
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if (probe_kernel_address(&check->fields.signature, sig))
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continue;
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if (check->fields.signature != BIOS32_SIGNATURE)
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continue;
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length = check->fields.length * 16;
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if (!length)
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continue;
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sum = 0;
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for (i = 0; i < length ; ++i)
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sum += check->chars[i];
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if (sum != 0)
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continue;
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if (check->fields.revision != 0) {
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printk("PCI: unsupported BIOS32 revision %d at 0x%p\n",
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check->fields.revision, check);
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continue;
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}
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DBG("PCI: BIOS32 Service Directory structure at 0x%p\n", check);
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if (check->fields.entry >= 0x100000) {
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printk("PCI: BIOS32 entry (0x%p) in high memory, "
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"cannot use.\n", check);
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return NULL;
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} else {
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unsigned long bios32_entry = check->fields.entry;
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DBG("PCI: BIOS32 Service Directory entry at 0x%lx\n",
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bios32_entry);
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bios32_indirect.address = bios32_entry + PAGE_OFFSET;
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set_bios_x();
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if (check_pcibios())
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return &pci_bios_access;
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}
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break; /* Hopefully more than one BIOS32 cannot happen... */
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}
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return NULL;
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}
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/*
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* BIOS Functions for IRQ Routing
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*/
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struct irq_routing_options {
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u16 size;
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struct irq_info *table;
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u16 segment;
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} __attribute__((packed));
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struct irq_routing_table * pcibios_get_irq_routing_table(void)
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{
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struct irq_routing_options opt;
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struct irq_routing_table *rt = NULL;
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int ret, map;
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unsigned long page;
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if (!pci_bios_present)
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return NULL;
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page = __get_free_page(GFP_KERNEL);
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if (!page)
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return NULL;
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opt.table = (struct irq_info *) page;
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opt.size = PAGE_SIZE;
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opt.segment = __KERNEL_DS;
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DBG("PCI: Fetching IRQ routing table... ");
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__asm__("push %%es\n\t"
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"push %%ds\n\t"
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"pop %%es\n\t"
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"lcall *(%%esi); cld\n\t"
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"pop %%es\n\t"
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"jc 1f\n\t"
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"xor %%ah, %%ah\n"
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"1:"
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: "=a" (ret),
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"=b" (map),
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"=m" (opt)
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: "0" (PCIBIOS_GET_ROUTING_OPTIONS),
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"1" (0),
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"D" ((long) &opt),
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"S" (&pci_indirect),
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"m" (opt)
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: "memory");
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DBG("OK ret=%d, size=%d, map=%x\n", ret, opt.size, map);
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if (ret & 0xff00)
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printk(KERN_ERR "PCI: Error %02x when fetching IRQ routing table.\n", (ret >> 8) & 0xff);
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else if (opt.size) {
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rt = kmalloc(sizeof(struct irq_routing_table) + opt.size, GFP_KERNEL);
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if (rt) {
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memset(rt, 0, sizeof(struct irq_routing_table));
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rt->size = opt.size + sizeof(struct irq_routing_table);
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rt->exclusive_irqs = map;
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memcpy(rt->slots, (void *) page, opt.size);
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printk(KERN_INFO "PCI: Using BIOS Interrupt Routing Table\n");
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}
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}
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free_page(page);
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return rt;
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}
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EXPORT_SYMBOL(pcibios_get_irq_routing_table);
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int pcibios_set_irq_routing(struct pci_dev *dev, int pin, int irq)
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{
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int ret;
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__asm__("lcall *(%%esi); cld\n\t"
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"jc 1f\n\t"
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"xor %%ah, %%ah\n"
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"1:"
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: "=a" (ret)
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: "0" (PCIBIOS_SET_PCI_HW_INT),
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"b" ((dev->bus->number << 8) | dev->devfn),
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"c" ((irq << 8) | (pin + 10)),
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"S" (&pci_indirect));
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return !(ret & 0xff00);
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}
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EXPORT_SYMBOL(pcibios_set_irq_routing);
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void __init pci_pcbios_init(void)
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{
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if ((pci_probe & PCI_PROBE_BIOS)
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&& ((raw_pci_ops = pci_find_bios()))) {
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pci_bios_present = 1;
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}
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}
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