diff options
| -rw-r--r-- | util-linux/Config.in | 11 | ||||
| -rw-r--r-- | util-linux/mdev.c | 75 |
2 files changed, 84 insertions, 2 deletions
diff --git a/util-linux/Config.in b/util-linux/Config.in index 2184df153..1040ce282 100644 --- a/util-linux/Config.in +++ b/util-linux/Config.in @@ -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 diff --git a/util-linux/mdev.c b/util-linux/mdev.c index d1b2684bc..8e5b8a94b 100644 --- a/util-linux/mdev.c +++ b/util-linux/mdev.c @@ -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); |