Adding documentation explaining the new MAPv5 packet format
and the corresponding checksum offload header.
Signed-off-by: Sharath Chandra Vurukala <shara...@codeaurora.org>
---
.../device_drivers/cellular/qualcomm/rmnet.rst | 53 ++++++++++++++++++++--
1 file changed, 49 insertions(+), 4 deletions(-)
diff --git
a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
index 70643b5..8c81f19 100644
--- a/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
+++ b/Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
@@ -27,7 +27,7 @@ these MAP frames and send them to appropriate PDN's.
2. Packet format
================
-a. MAP packet (data / control)
+a. MAP packet v1 (data / control)
MAP header has the same endianness of the IP packet.
@@ -35,8 +35,9 @@ Packet format::
Bit 0 1 2-7 8 - 15 16 - 31
Function Command / Data Reserved Pad Multiplexer ID Payload
length
- Bit 32 - x
- Function Raw Bytes
+
+ Bit 32-x
+ Function Raw bytes
Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
or data packet. Control packet is used for transport level flow control. Data
@@ -52,7 +53,51 @@ Multiplexer ID is to indicate the PDN on which data has to
be sent.
Payload length includes the padding length but does not include MAP header
length.
-b. MAP packet (command specific)::
+b. MAP packet v5 (data / control)
+
+MAP header has the same endianness of the IP packet.
+
+Packet format::
+
+ Bit 0 1 2-7 8 - 15 16 - 31
+ Function Command / Data Next Header Pad Multiplexer ID Payload length
+
+ Bit 32 - 38 1 40 41-63
+ Function Header Type Next Header Checksum Valid Reserved
+
+ Bit 64-x
+ Function Raw bytes
+
+Command (1)/ Data (0) bit value is to indicate if the packet is a MAP command
+or data packet. Control packet is used for transport level flow control. Data
+packets are standard IP packets.
+
+Next header is used to indicate the presence of another header, currently is
+limited to checksum header.
+
+Padding is number of bytes to be added for 4 byte alignment if required by
+hardware.
+
+Multiplexer ID is to indicate the PDN on which data has to be sent.
+
+Payload length includes the padding length but does not include MAP header
+length.
+
+Header Type is to indicate the type of header, this usually is set to CHECKSUM
+
+Header types
+= ==========================================
+0 Reserved
+1 Reserved
+2 checksum header
+
+Checksum Valid is to indicate whether the header checksum is valid. Value of 1
+implies that checksum is calculated on this packet and is valid, value of 0
+indicates that the calculated packet checksum is invalid.
+
+Reserved bits are usually zeroed out and to be ignored by receiver.
+
+c. MAP packet v1/v5 (command specific)::
Bit 0 1 2-7 8 - 15 16 - 31
Function Command Reserved Pad Multiplexer ID Payload
length
--
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