Merge branch 'add-rmnet-driver'

Subash Abhinov Kasiviswanathan says:

====================
net: Add support for rmnet driver

This patch series adds support for the rmnet driver which is required to
support recent chipsets using Qualcomm Technologies, Inc. modems. The data
from hardware follows the multiplexing and aggregation protocol (MAP).

This driver can be used to register onto any physical network device in
IP mode. Physical transports include USB, HSIC, PCIe and IP accelerator.

rmnet driver helps to decode these packets and queue them to network
stack (and encode and transmit it to the physical device).

v1: Same as the RFC patch with some minor fixes for issues reported by
kbuild test robot.

v1->v2: Change datatypes and remove config IOCTL as mentioned by David.
Also fix checkpatch issues and remove some unused code.

v2->v3: Move location to drivers/net and rename to rmnet. Change the
userspace - netlink communication from custom netlink to rtnl_link_ops.
Refactor some code. Use a fixed config for ingress and egress.

v3->v4: Move location to drivers/net/ethernet/qualcomm/.
Fix comments from Stephen and Jiri -
Split the ether and arp type changes into seperate patches.
Remove debug and custom logging and switch to standard netdevice log.
Remove module parameters. Refactor and change some code style issues.

v4->v5: Rename some structs and variables. Move the initializer
before the for loop start. Put the arp type in correct sequence.

v5->v6: Fix comments from Dan -
Use the upper link API. As a result, remove all the refcounting logic.
Device refcount is explicitly held on real_dev on rx_handler
registration only. Modifiy the flow control struct. Remove the unused
ethernet mode handling.

v6->v7: Fix comments from David - Add newline to end of Makefile. Remove
inline from .c files. Move the module init/exit to rmnet config. Fix an
error reported by kbuild test robot for an unused file.

v7->v8: Use a smaller value for ETH_P_MAP as mentioned by David. Change
netdev_info to netdev_dbg as mentioned by Andew. Fix comments from
Stephen regarding netdev_priv and sparse related errors of using 0 as NULL

v8->v9: Fix comments from David - Remove the CFLAG rule. Change the way
rmnet devices are freed. Instead of using a workqueue to unregister devices
individually, go through the list and free all devices within the rtnl_lock().

v9->v10: Actually fix the locking as mentioned by David. The locking scheme is
mentioned in a comment in rmnet_config.c. Change comment near MAP type
definition as mentioned by Dan. Refactor some code.

v10->v11: Allow RMNET to compile as a module as mentioned by David
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/rmnet.txt

@@ -0,0 +1,82 @@
+1. Introduction
+
+rmnet driver is used for supporting the Multiplexing and aggregation
+Protocol (MAP). This protocol is used by all recent chipsets using Qualcomm
+Technologies, Inc. modems.
+
+This driver can be used to register onto any physical network device in
+IP mode. Physical transports include USB, HSIC, PCIe and IP accelerator.
+
+Multiplexing allows for creation of logical netdevices (rmnet devices) to
+handle multiple private data networks (PDN) like a default internet, tethering,
+multimedia messaging service (MMS) or IP media subsystem (IMS). Hardware sends
+packets with MAP headers to rmnet. Based on the multiplexer id, rmnet
+routes to the appropriate PDN after removing the MAP header.
+
+Aggregation is required to achieve high data rates. This involves hardware
+sending aggregated bunch of MAP frames. rmnet driver will de-aggregate
+these MAP frames and send them to appropriate PDN's.
+
+2. Packet format
+
+a. MAP packet (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   Reserved     Pad   Multiplexer ID    Payload length
+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
+packets are standard IP packets.
+
+Reserved bits are usually zeroed out and to be ignored by receiver.
+
+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.
+
+b. MAP packet (command specific)
+
+Bit             0             1           2-7      8 - 15           16 - 31
+Function   Command         Reserved     Pad   Multiplexer ID    Payload length
+Bit          32 - 39        40 - 45    46 - 47       48 - 63
+Function   Command name    Reserved   Command Type   Reserved
+Bit          64 - 95
+Function   Transaction ID
+Bit          96 - 127
+Function   Command data
+
+Command 1 indicates disabling flow while 2 is enabling flow
+
+Command types -
+0 for MAP command request
+1 is to acknowledge the receipt of a command
+2 is for unsupported commands
+3 is for error during processing of commands
+
+c. Aggregation
+
+Aggregation is multiple MAP packets (can be data or command) delivered to
+rmnet in a single linear skb. rmnet will process the individual
+packets and either ACK the MAP command or deliver the IP packet to the
+network stack as needed
+
+MAP header|IP Packet|Optional padding|MAP header|IP Packet|Optional padding....
+MAP header|IP Packet|Optional padding|MAP header|Command Packet|Optional pad...
+
+3. Userspace configuration
+
+rmnet userspace configuration is done through netlink library librmnetctl
+and command line utility rmnetcli. Utility is hosted in codeaurora forum git.
+The driver uses rtnl_link_ops for communication.
+
+https://source.codeaurora.org/quic/la/platform/vendor/qcom-opensource/dataservices/tree/rmnetctl

drivers/net/ethernet/qualcomm/Kconfig

@@ -59,4 +59,6 @@ config QCOM_EMAC
 	  low power, Receive-Side Scaling (RSS), and IEEE 1588-2008
 	  Precision Clock Synchronization Protocol.
 
+source "drivers/net/ethernet/qualcomm/rmnet/Kconfig"
+
 endif # NET_VENDOR_QUALCOMM

drivers/net/ethernet/qualcomm/Makefile

@@ -9,3 +9,5 @@ obj-$(CONFIG_QCA7000_UART) += qcauart.o
 qcauart-objs := qca_uart.o
 
 obj-y += emac/
+
+obj-$(CONFIG_RMNET) += rmnet/

drivers/net/ethernet/qualcomm/rmnet/Kconfig

@@ -0,0 +1,12 @@
+#
+# RMNET MAP driver
+#
+
+menuconfig RMNET
+	tristate "RmNet MAP driver"
+	default n
+	---help---
+	  If you select this, you will enable the RMNET module which is used
+	  for handling data in the multiplexing and aggregation protocol (MAP)
+	  format in the embedded data path. RMNET devices can be attached to
+	  any IP mode physical device.

drivers/net/ethernet/qualcomm/rmnet/Makefile

@@ -0,0 +1,10 @@
+#
+# Makefile for the RMNET module
+#
+
+rmnet-y		 := rmnet_config.o
+rmnet-y		 += rmnet_vnd.o
+rmnet-y		 += rmnet_handlers.o
+rmnet-y		 += rmnet_map_data.o
+rmnet-y		 += rmnet_map_command.o
+obj-$(CONFIG_RMNET) += rmnet.o