greybus: add support for the log protocol

Add support for the new Log class/protocol. This protocol allows modules
to send their internal logging messages to the AP in order to make
module debugging easier.

The protocol is, for now, composed a single module-initiated request.
This request contains a message and associated length. The message is
integrated in the kernel log with dev_dbg(). In order to be displayed
with 'dmesg', the following command needs to be entered first:

$ echo "file log.c +p" > /sys/kernel/debug/dynamic_debug/control

The major portion of this file was initially written by Greg KH.

Signed-off-by: Joel Porquet <porquet_joel@projectara.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/staging/greybus/greybus_protocols.h b/drivers/staging/greybus/greybus_protocols.h
index 63dd204..203bc46 100644
--- a/drivers/staging/greybus/greybus_protocols.h
+++ b/drivers/staging/greybus/greybus_protocols.h
@@ -2136,5 +2136,19 @@ struct gb_audio_send_data_request {
 	__u8	data[0];
 } __packed;
 
+
+/* Log */
+
+/* operations */
+#define GB_LOG_TYPE_SEND_LOG	0x02
+
+/* length */
+#define GB_LOG_MAX_LEN		1024
+
+struct gb_log_send_log_request {
+	__le16	len;
+	__u8    msg[0];
+} __packed;
+
 #endif /* __GREYBUS_PROTOCOLS_H */