[PATCH] Add subsystem support to mdev (firmware loading)

[Michael-Luke Jones]

Hi there,

I'm enclosing a patch that allows mdev to call external scripts to  
deal with 'subsystem' hotplug requests. I also enclose a script to  
handle firmware loading (via firmware_class) which has been tested  
with the 2.6.18 kernel on an NSLU2.

--- busybox-1.2.1.orig/util-linux/mdev.c 2006-07-01  
00:42:13.000000000 +0200
+++ busybox-1.2.1/util-linux/mdev.c	2006-09-26 17:42:38.414162744 +0200
@@ -255,7 +255,16 @@
			bb_show_usage();
		sprintf(temp, "/sys%s", env_path);
-		if (!strcmp(action, "add")) make_device(temp,0);
+		if (!strcmp(action, "add")) {
+			struct stat st;
+			make_device(temp,0);
+			sprintf(temp, "/lib/mdev/%s", getenv("SUBSYSTEM"));
+			if (stat(temp, &st) == 0) {
+				if ((st.st_mode & S_IXUSR) && S_ISREG(st.st_mode)) {
+					system(temp);
+				}
+			}
+		}
		else if (!strcmp(action, "remove")) make_device(temp,1);
	}

--Script should be dropped into /lib/mdev/firmware--
#!/bin/sh

firmwaredir=/lib/firmware

if test "$SUBSYSTEM" = "firmware" -a "$ACTION" = "add"; then
if test -f $firmwaredir/$FIRMWARE; then
    echo 1 > /sys/$DEVPATH/loading
    cat $firmwaredir/$FIRMWARE > /sys/$DEVPATH/data
    echo 0 > /sys/$DEVPATH/loading
else
    echo -1 > /sys/$DEVPATH/loading
fi
fi

Firmware loading is vital for certain embedded systems such as all  
IXP4xx boards when the GPL Ethernet driver is used. I hope that this  
patch or a variation can be included in BusyBox 1.3.0. Christian  
Hohnstaedt is the author of this patch and he is CCed on this email.  
I've got his permission to send them to you.

Michael-Luke Jones