libbb: library for bit-banging the Ben's uSD port (in progress)
This doesn't work with old kernels, but 2.6.36 should be better. Haven't tried it yet, though.
This commit is contained in:
Werner Almesberger
parent
1d72af733e
commit
458702cf54
|
|
@ -0,0 +1,35 @@
|
|||
CC = mipsel-openwrt-linux-uclibc-gcc
|
||||
|
||||
PREFIX = /usr/local
|
||||
|
||||
LIBBD_PATH = $(PREFIX)/lib/libbbd
|
||||
|
||||
CFLAGS = -Wall -DLIBBD_PATH='"$(LIBBD_PATH)"'
|
||||
|
||||
MAIN = libbb.a libbbd
|
||||
|
||||
.PHONY: all install uninstall clean spotless upload
|
||||
|
||||
all: $(MAIN)
|
||||
|
||||
libbb.a: libbb.o
|
||||
$(AR) cr $@ $^
|
||||
|
||||
libbb.o libbd: libbb.h
|
||||
|
||||
install: $(MAIN)
|
||||
install -D libbb.a $(PREFIX)/lib/
|
||||
install -D libbbd $(LIBBD_PATH)
|
||||
|
||||
uninstall:
|
||||
rm -f $(PREFIX)/lib/libbb.a
|
||||
rm -f $(LIBBD_PATH)
|
||||
|
||||
clean:
|
||||
rm -f libbb.o
|
||||
|
||||
spotless: clean
|
||||
rm -f $(MAIN)
|
||||
|
||||
upload: libbbd
|
||||
scp libbbd ben:/usr/local/lib/
|
||||
|
|
@ -0,0 +1,126 @@
|
|||
/*
|
||||
* libbb/libbb.c - Bitbang library
|
||||
*
|
||||
* Written 2010 by Werner Almesberger
|
||||
* Copyright 2010 Werner Almesberger
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*/
|
||||
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <unistd.h>
|
||||
#include <string.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/socket.h>
|
||||
//#include <sys/wait.h>
|
||||
#include <sys/mman.h>
|
||||
|
||||
#include "libbb.h"
|
||||
|
||||
|
||||
#define PAGE_SIZE 4096
|
||||
|
||||
|
||||
volatile void *libbb_mem;
|
||||
|
||||
static int bbd_fd = -1;
|
||||
|
||||
|
||||
static int recv_fd(int s)
|
||||
{
|
||||
struct msghdr msg;
|
||||
struct cmsg {
|
||||
struct cmsghdr hdr;
|
||||
int fd;
|
||||
} cmsg;
|
||||
|
||||
memset(&msg, 0, sizeof(msg));
|
||||
msg.msg_control = &cmsg;
|
||||
msg.msg_controllen = sizeof(cmsg);
|
||||
if (recvmsg(s, &msg, 0) < 0) {
|
||||
perror("recvmsg");
|
||||
exit(1);
|
||||
}
|
||||
return cmsg.fd;
|
||||
}
|
||||
|
||||
|
||||
static void child(void)
|
||||
{
|
||||
execl(LIBBD_PATH, LIBBD_PATH, NULL);
|
||||
perror(LIBBD_PATH);
|
||||
_exit(1);
|
||||
}
|
||||
|
||||
|
||||
#if 0
|
||||
static int recv_fd(int s)
|
||||
{
|
||||
pid_t res;
|
||||
|
||||
res = waitpid(pid, &status, 0);
|
||||
if (res < 0) {
|
||||
perror("waitpid");
|
||||
exit(1);
|
||||
}
|
||||
if (res != pid) {
|
||||
fprintf(stderr, "waitpid returned %d for %d\n",
|
||||
(int) res, (int) pid);
|
||||
exit(1);
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
|
||||
static int bbd(void)
|
||||
{
|
||||
int s[2];
|
||||
pid_t pid;
|
||||
|
||||
if (socketpair(PF_LOCAL, SOCK_DGRAM, 0, s) < 0) {
|
||||
perror("socketpair");
|
||||
exit(1);
|
||||
}
|
||||
if (dup2(s[1], 1) < 0) {
|
||||
perror("dup2");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
pid = fork();
|
||||
if (pid < 0) {
|
||||
perror("fork");
|
||||
exit(1);
|
||||
}
|
||||
if (pid)
|
||||
return recv_fd(s[0]);
|
||||
else
|
||||
child();
|
||||
return -1; /* can't happen */
|
||||
}
|
||||
|
||||
|
||||
void libbb_open(void)
|
||||
{
|
||||
bbd_fd = bbd();
|
||||
libbb_mem = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
|
||||
bbd_fd, LIBBB_GPIO_BASE);
|
||||
if (libbb_mem == MAP_FAILED) {
|
||||
perror("mmap");
|
||||
exit(1);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
|
||||
void libbb_close(void)
|
||||
{
|
||||
if (close(bbd_fd) < 0) {
|
||||
perror("close");
|
||||
exit(1);
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,193 @@
|
|||
/*
|
||||
* libbb/libbbd.c - Bitbang library daemon
|
||||
*
|
||||
* Written 2010 by Werner Almesberger
|
||||
* Copyright 2010 Werner Almesberger
|
||||
*
|
||||
* This program is free software; you can redistribute it and/or modify
|
||||
* it under the terms of the GNU General Public License as published by
|
||||
* the Free Software Foundation; either version 2 of the License, or
|
||||
* (at your option) any later version.
|
||||
*/
|
||||
|
||||
|
||||
#include <stdlib.h>
|
||||
#include <stdio.h>
|
||||
#include <unistd.h>
|
||||
#include <string.h>
|
||||
#include <fcntl.h>
|
||||
#include <dirent.h>
|
||||
#include <poll.h>
|
||||
#include <errno.h>
|
||||
#include <syslog.h>
|
||||
#include <sys/types.h>
|
||||
#include <sys/socket.h>
|
||||
|
||||
#include "libbb.h"
|
||||
|
||||
|
||||
#define FD_DIR "/proc/self/fd"
|
||||
|
||||
#define DRIVER_NAME "jz4740-mmc.0"
|
||||
#define UNBIND_PATH "/sys/bus/platform/drivers/jz4740-mmc/unbind"
|
||||
#define BIND_PATH "/sys/bus/platform/drivers/jz4740-mmc/bind"
|
||||
|
||||
|
||||
static void closefds(void)
|
||||
{
|
||||
DIR *dir;
|
||||
const struct dirent *de;
|
||||
int fd;
|
||||
|
||||
dir = opendir(FD_DIR);
|
||||
if (!dir) {
|
||||
perror(FD_DIR);
|
||||
exit(1);
|
||||
}
|
||||
while ((de = readdir(dir))) {
|
||||
if (*de->d_name == '.')
|
||||
continue;
|
||||
fd = atoi(de->d_name);
|
||||
if (fd == 1 || fd == 2)
|
||||
continue;
|
||||
if (fd == dirfd(dir))
|
||||
continue;
|
||||
(void) close(fd);
|
||||
}
|
||||
closedir(dir);
|
||||
}
|
||||
|
||||
|
||||
static int echo(const char *msg, const char *path)
|
||||
{
|
||||
int fd;
|
||||
ssize_t wrote;
|
||||
int len = strlen(msg);
|
||||
|
||||
fd = open(path, O_WRONLY);
|
||||
if (fd < 0) {
|
||||
perror(path);
|
||||
return -errno;
|
||||
}
|
||||
wrote = write(fd, msg, len);
|
||||
if (wrote < 0) {
|
||||
perror(path);
|
||||
return -errno;
|
||||
}
|
||||
if (wrote != len) {
|
||||
fprintf(stderr, "short write: %d < %d\n", (int) wrote, len);
|
||||
return -ENOSPC;
|
||||
}
|
||||
if (close(fd) < 0) {
|
||||
perror(path);
|
||||
return -errno;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
static void lock_area(int fd, off_t from, off_t len)
|
||||
{
|
||||
if (lseek(fd, from, SEEK_SET) == (off_t) -1) {
|
||||
perror("lseek");
|
||||
exit(1);
|
||||
}
|
||||
if (lockf(fd, F_LOCK, len) < 0) {
|
||||
perror("lockf");
|
||||
exit(1);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
static int send_fd(int s, int fd)
|
||||
{
|
||||
struct msghdr msg;
|
||||
struct cmsg {
|
||||
struct cmsghdr hdr;
|
||||
int fd;
|
||||
} cmsg;
|
||||
|
||||
memset(&msg, 0, sizeof(msg));
|
||||
msg.msg_control = &cmsg;
|
||||
msg.msg_controllen = sizeof(cmsg);
|
||||
cmsg.hdr.cmsg_level = SOL_SOCKET;
|
||||
cmsg.hdr.cmsg_type = SCM_RIGHTS;
|
||||
cmsg.hdr.cmsg_len = sizeof(cmsg);
|
||||
cmsg.fd = fd;
|
||||
if (sendmsg(s, &msg, 0) >= 0)
|
||||
return 0;
|
||||
perror("sendmsg");
|
||||
return -1;
|
||||
}
|
||||
|
||||
|
||||
static int wait_for_close(int s)
|
||||
{
|
||||
struct pollfd fds[1];
|
||||
int res;
|
||||
|
||||
fds->fd = s;
|
||||
fds->events = 0;
|
||||
fds->revents = POLLHUP;
|
||||
res = poll(fds, 1, -1);
|
||||
if (res < 0) {
|
||||
perror("poll");
|
||||
return -1;
|
||||
}
|
||||
if (!res) {
|
||||
fprintf(stderr, "poll inexplicably returned 0\n");
|
||||
return -1;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
int fd, res;
|
||||
int exit_code = 1;
|
||||
|
||||
fprintf(stderr, "setsid\n");
|
||||
if (setsid() == (pid_t) -1) {
|
||||
perror("setsid");
|
||||
exit(1);
|
||||
}
|
||||
fprintf(stderr, "closefds\n");
|
||||
closefds();
|
||||
|
||||
fprintf(stderr, "open devmem\n");
|
||||
fd = open("/dev/mem", O_RDWR);
|
||||
if (fd < 0) {
|
||||
perror("/dev/mem");
|
||||
exit(1);
|
||||
}
|
||||
fprintf(stderr, "lock_area\n");
|
||||
lock_area(fd, LIBBB_GPIO_BASE+LIBBB_PORT_D_OFFSET,
|
||||
LIBBB_PORT_D_WINDOW);
|
||||
|
||||
fprintf(stderr, "echo (unbind)\n");
|
||||
if (echo(DRIVER_NAME "\n", UNBIND_PATH) < 0)
|
||||
exit(1);
|
||||
|
||||
fprintf(stderr, "send_fd\n");
|
||||
if (send_fd(1, fd) < 0)
|
||||
goto cleanup;
|
||||
|
||||
fprintf(stderr, "wait_for_close\n");
|
||||
if (wait_for_close(1) < 0)
|
||||
goto cleanup;
|
||||
|
||||
exit_code = 0;
|
||||
|
||||
cleanup:
|
||||
fprintf(stderr, "echo (bind)n");
|
||||
res = echo(DRIVER_NAME "\n", BIND_PATH);
|
||||
if (res < 0) {
|
||||
/* stderr may no longer exist. report to syslog. */
|
||||
openlog("libbbd", LOG_CONS, LOG_USER);
|
||||
syslog(LOG_CRIT, "libbd failed to re-bind driver (%d)", res);
|
||||
}
|
||||
|
||||
fprintf(stderr, "exit\n");
|
||||
return exit_code;
|
||||
}
|
||||
Loading…
Reference in New Issue