misc: kernel_debugger: Add help command

Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/drivers/misc/kernel_debugger.c b/drivers/misc/kernel_debugger.c
index 20e1abb..4a9fef6 100644
--- a/drivers/misc/kernel_debugger.c
+++ b/drivers/misc/kernel_debugger.c
@@ -65,6 +65,14 @@
 	}
 }
 
+static void do_help(struct kdbg_ctxt *ctxt)
+{
+	dprintf("Kernel Debugger commands:\n");
+	dprintf(" ps            Process list\n");
+	dprintf(" sysrq         sysrq options\n");
+	dprintf(" sysrq <param> Execute sysrq with <param>\n");
+}
+
 int kernel_debugger(struct kdbg_ctxt *ctxt, char *cmd)
 {
 	if (!strcmp(cmd, "ps"))
@@ -73,6 +81,8 @@
 		do_sysrq(ctxt, 'h');
 	if (!strncmp(cmd, "sysrq ", 6))
 		do_sysrq(ctxt, cmd[6]);
+	if (!strcmp(cmd, "help"))
+		do_help(ctxt);
 
 	return 0;
 }