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* probe_roms - scan for Adapter ROMS
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* (based on linux-2.6:arch/x86/kernel/probe_roms_32.c)
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* Copyright (C) 2008 Intel Corporation
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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#include "probe_roms.h"
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#include <sys/types.h>
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#include <asm/types.h>
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static void *rom_mem = MAP_FAILED;
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static int rom_fd = -1;
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static const int rom_len = 0xf0000 - 0xc0000; /* option-rom memory region */
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static unsigned long rom_align;
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#define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
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static void sigbus(int sig)
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static int probe_address8(const __u8 *ptr, __u8 *val)
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static int probe_address16(const __u16 *ptr, __u16 *val)
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void probe_roms_exit(void)
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signal(SIGBUS, SIG_DFL);
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if (rom_mem != MAP_FAILED) {
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munmap(rom_mem, rom_len);
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int probe_roms_init(unsigned long align)
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/* valid values are 2048 and 512. 512 is for PCI-3.0 compliant
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* systems, or systems that do not have dangerous/legacy ISA
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* devices. 2048 should always be safe
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if (align == 512 || align == 2048)
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if (signal(SIGBUS, sigbus) == SIG_ERR)
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fd = open("/dev/mem", O_RDONLY);
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rom_mem = mmap(NULL, rom_len, PROT_READ, MAP_PRIVATE, fd, 0xc0000);
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if (rom_mem == MAP_FAILED)
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* isa_bus_to_virt - convert physical address to mmap'd region
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* @addr - address to convert
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* Only valid between a successful call to probe_roms_init and the
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* corresponding probe_roms_exit
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static void *isa_bus_to_virt(unsigned long addr)
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return rom_mem + (addr - 0xc0000);
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static struct resource system_rom_resource = {
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.name = "System ROM",
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static struct resource extension_rom_resource = {
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.name = "Extension ROM",
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static struct resource adapter_rom_resources[] = { {
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.name = "Adapter ROM",
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.name = "Adapter ROM",
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.name = "Adapter ROM",
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.name = "Adapter ROM",
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.name = "Adapter ROM",
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.name = "Adapter ROM",
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static struct resource video_rom_resource = {
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#define ROMSIGNATURE 0xaa55
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static int romsignature(const unsigned char *rom)
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const unsigned short * const ptr = (const unsigned short *)rom;
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unsigned short sig = 0;
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return probe_address16(ptr, &sig) == 0 && sig == ROMSIGNATURE;
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static int romchecksum(const unsigned char *rom, unsigned long length)
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unsigned char sum, c;
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for (sum = 0; length && probe_address8(rom++, &c) == 0; length--)
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return !length && !sum;
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int scan_adapter_roms(scan_fn fn)
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/* let scan_fn examing each of the adapter roms found by probe_roms */
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for (i = 0; i < ARRAY_SIZE(adapter_rom_resources); i++) {
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struct resource *res = &adapter_rom_resources[i];
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found = fn(isa_bus_to_virt(res->start),
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isa_bus_to_virt(res->end));
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static unsigned long align(unsigned long addr, unsigned long alignment)
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return (addr + alignment - 1) & ~(alignment - 1);
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void probe_roms(void)
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unsigned long start, length, upper;
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upper = adapter_rom_resources[0].start;
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for (start = video_rom_resource.start; start < upper; start += rom_align) {
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rom = isa_bus_to_virt(start);
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if (!romsignature(rom))
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video_rom_resource.start = start;
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if (probe_address8(rom + 2, &c) != 0)
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/* 0 < length <= 0x7f * 512, historically */
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/* if checksum okay, trust length byte */
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if (length && romchecksum(rom, length))
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video_rom_resource.end = start + length - 1;
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start = align(video_rom_resource.end + 1, rom_align);
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upper = system_rom_resource.start;
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/* check for extension rom (ignore length byte!) */
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rom = isa_bus_to_virt(extension_rom_resource.start);
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if (romsignature(rom)) {
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length = extension_rom_resource.end - extension_rom_resource.start + 1;
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if (romchecksum(rom, length))
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upper = extension_rom_resource.start;
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/* check for adapter roms on 2k boundaries */
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for (i = 0; i < ARRAY_SIZE(adapter_rom_resources) && start < upper; start += rom_align) {
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rom = isa_bus_to_virt(start);
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if (!romsignature(rom))
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if (probe_address8(rom + 2, &c) != 0)
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/* 0 < length <= 0x7f * 512, historically */
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/* but accept any length that fits if checksum okay */
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if (!length || start + length > upper || !romchecksum(rom, length))
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adapter_rom_resources[i].start = start;
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adapter_rom_resources[i].end = start + length - 1;
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start = adapter_rom_resources[i++].end & ~(rom_align - 1);