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Merge pull request #50 from jepler/cm4-pci-v2

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pci_boards: Enable the board before mmap'ing it
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Jeff Epler 2021-05-04 11:27:38 -05:00 committed by GitHub
commit 3fc88b0f42
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1 changed files with 41 additions and 0 deletions
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41
pci_boards.c
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@ -42,6 +42,27 @@
#include "bitfile.h"
#include "pci_boards.h"
#ifdef __linux__
static int open_as_root(const char *path, int flags) {
if (seteuid(0) != 0) {
printf("You need root privileges (or setuid root) to access PCI hardware\n");
return -1;
}
int fd = open(path, flags);
int eno = errno;
if (seteuid(getuid()) != 0) {
printf("Failed to restore euid: %s\n", strerror(errno));
return -1;
}
if (fd < 0) {
errno = eno;
printf("%s can't open /dev/mem: %s", __func__, strerror(errno));
}
return fd;
}
#endif
extern board_t boards[MAX_BOARDS];
extern int boards_count;
static int memfd = -1;
@ -768,6 +789,16 @@ static void pci_fix_bar_lengths(struct pci_dev *dev) {
static int pci_board_open(board_t *board) {
if (board->mem_base != 0) {
#ifdef __linux__
char path[256];
struct pci_dev *dev = board->dev;
snprintf(path, sizeof(path), "/sys/bus/pci/devices/%04x:%02x:%02x.%x/enable", dev->domain, dev->bus, dev->dev, dev->func);
int enable_fd = open_as_root(path, O_RDWR);
if (enable_fd < 0) {
perror("open_as_root(enable)");
abort();
}
write(enable_fd, "1\n", 2);
close(enable_fd);
board->base = mmap(0, board->len, PROT_READ | PROT_WRITE, MAP_SHARED, memfd, board->mem_base);
if (board->base == NULL || board->base == MAP_FAILED) {
perror("mmap pci");
@ -795,6 +826,16 @@ static int pci_board_close(board_t *board) {
if (board->base) {
#ifdef __linux__
munmap(board->base, board->len);
char path[256];
struct pci_dev *dev = board->dev;
snprintf(path, sizeof(path), "/sys/bus/pci/devices/%04x:%02x:%02x.%x/enable", dev->domain, dev->bus, dev->dev, dev->func);
int enable_fd = open_as_root(path, O_RDWR);
if (enable_fd < 0) {
perror("open_as_root(enable)");
abort();
}
write(enable_fd, "0\n", 2);
close(enable_fd);
#elif _WIN32
unmap_memory(&(board->mem_handle));
#endif