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-rw-r--r--util-linux/Config.in11
-rw-r--r--util-linux/mdev.c75
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);