umka/linux/pci.c

46 lines
1.3 KiB
C

/*
SPDX-License-Identifier: GPL-2.0-or-later
UMKa - User-Mode KolibriOS developer tools
Copyright (C) 2020-2021 Ivan Baravy <dunkaist@gmail.com>
*/
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <limits.h>
#include "pci.h"
char pci_path[PATH_MAX] = ".";
__attribute__((stdcall)) uint32_t pci_read(uint32_t bus, uint32_t dev,
uint32_t fun, uint32_t offset,
size_t len) {
char path_colon[PATH_MAX*2];
char path_underscore[PATH_MAX*2];
uint32_t value = 0;
sprintf(path_colon, "%s/%4.4x:%2.2x:%2.2x.%u/config", pci_path, 0, bus, dev,
fun);
sprintf(path_underscore, "%s/%4.4x_%2.2x_%2.2x.%u/config", pci_path, 0, bus,
dev, fun);
int fd = open(path_colon, O_RDONLY);
if (fd == -1) {
fd = open(path_underscore, O_RDONLY);
if (fd == -1) {
// fprintf(stderr, "[pci] error: failed to open config file '%s': %s\n",
// path, strerror(errno));
return UINT32_MAX;
}
}
lseek(fd, offset, SEEK_SET);
read(fd, &value, len);
close(fd);
return value;
}