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add support for firmware loading

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This commit is contained in:
Mike Frysinger 2007-06-13 07:34:15 +00:00
parent d67cef2425
commit a78ef2ccf1
2 changed files with 84 additions and 2 deletions
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11
util-linux/Config.in
View File

@ -294,6 +294,17 @@ config FEATURE_MDEV_EXEC
For more information, please see docs/mdev.txt
config FEATURE_MDEV_LOAD_FIRMWARE
bool "Support loading of firmwares"
default n
depends on MDEV
help
Some devices need to load firmware before they can be usable.
These devices will request userspace look up the files in
/lib/firmware/ and if it exists, send it to the kernel for
loading into the hardware.
config MKSWAP
bool "mkswap"
default n

75
util-linux/mdev.c
View File

@ -226,6 +226,71 @@ static void find_dev(char *path)
closedir(dir);
}
/* For the full gory details, see linux/Documentation/firmware_class/README
*
* Firmware loading works like this:
* - kernel sets FIRMWARE env var
* - userspace checks /lib/firmware/$FIRMWARE
* - userspace waits for /sys/$DEVPATH/loading to appear
* - userspace writes "1" to /sys/$DEVPATH/loading
* - userspace copies /lib/firmware/$FIRMWARE into /sys/$DEVPATH/data
* - userspace writes "0" (worked) or "-1" (failed) to /sys/$DEVPATH/loading
* - kernel loads firmware into device
*/
static inline void load_firmware(const char * const firmware, const char * const sysfs_path)
{
int cnt;
int firmware_fd, loading_fd, data_fd;
/* check for $FIRMWARE from kernel */
/* XXX: dont bother: open(NULL) works same as open("no-such-file")
* if (!firmware)
* return;
*/
/* check for /lib/firmware/$FIRMWARE */
xchdir("/lib/firmware");
firmware_fd = xopen(firmware, O_WRONLY);
/* in case we goto out ... */
data_fd = -1;
/* check for /sys/$DEVPATH/loading ... give 30 seconds to appear */
xchdir(sysfs_path);
for (cnt = 0; cnt < 30; ++cnt) {
loading_fd = open("loading", O_WRONLY);
if (loading_fd == -1)
sleep(1);
else
break;
}
if (loading_fd == -1)
goto out;
/* tell kernel we're loading by `echo 1 > /sys/$DEVPATH/loading` */
if (write(loading_fd, "1", 1) != 1)
goto out;
/* load firmware by `cat /lib/firmware/$FIRMWARE > /sys/$DEVPATH/data */
data_fd = open("data", O_WRONLY);
if (data_fd == -1)
goto out;
cnt = bb_copyfd_eof(firmware_fd, data_fd);
/* tell kernel result by `echo [0|-1] > /sys/$DEVPATH/loading` */
if (cnt > 0)
write(loading_fd, "0", 1);
else
write(loading_fd, "-1", 2);
out:
if (ENABLE_FEATURE_CLEAN_UP) {
close(firmware_fd);
close(loading_fd);
close(data_fd);
}
}
int mdev_main(int argc, char **argv);
int mdev_main(int argc, char **argv)
{
@ -257,8 +322,14 @@ int mdev_main(int argc, char **argv)
bb_show_usage();
sprintf(temp, "/sys%s", env_path);
if (!strcmp(action, "add")) make_device(temp,0);
else if (!strcmp(action, "remove")) make_device(temp,1);
if (!strcmp(action, "remove"))
make_device(temp, 1);
else if (!strcmp(action, "add")) {
make_device(temp, 0);
if (ENABLE_FEATURE_MDEV_LOAD_FIRMWARE)
load_firmware(getenv("FIRMWARE"), temp);
}
}
if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);