Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

3 files changed, 492 insertions, 0 deletions

diff --git a/Documentation/networking/caif/Linux-CAIF.txt b/Documentation/networking/caif/Linux-CAIF.txt
new file mode 100644
index 000000000..0aa4bd381
--- /dev/null
+++ b/Documentation/networking/caif/Linux-CAIF.txt
@@ -0,0 +1,175 @@
+Linux CAIF
+===========
+copyright (C) ST-Ericsson AB 2010
+Author: Sjur Brendeland/ sjur.brandeland@stericsson.com
+License terms: GNU General Public License (GPL) version 2
+
+
+Introduction
+------------
+CAIF is a MUX protocol used by ST-Ericsson cellular modems for
+communication between Modem and host. The host processes can open virtual AT
+channels, initiate GPRS Data connections, Video channels and Utility Channels.
+The Utility Channels are general purpose pipes between modem and host.
+
+ST-Ericsson modems support a number of transports between modem
+and host. Currently, UART and Loopback are available for Linux.
+
+
+Architecture:
+------------
+The implementation of CAIF is divided into:
+* CAIF Socket Layer and GPRS IP Interface.
+* CAIF Core Protocol Implementation
+* CAIF Link Layer, implemented as NET devices.
+
+
+  RTNL
+   !
+   !	      +------+	 +------+
+   !	     +------+!	+------+!
+   !	     !	IP  !!	!Socket!!
+   +-------> !interf!+	! API  !+	<- CAIF Client APIs
+   !	     +------+	+------!
+   !		!	    !
+   !		+-----------+
+   !		      !
+   !		   +------+		<- CAIF Core Protocol
+   !		   ! CAIF !
+   !		   ! Core !
+   !		   +------+
+   !	   +----------!---------+
+   !	   !	      !		!
+   !	+------+   +-----+   +------+
+   +--> ! HSI  !   ! TTY !   ! USB  !	<- Link Layer (Net Devices)
+	+------+   +-----+   +------+
+
+
+
+I M P L E M E N T A T I O N
+===========================
+
+
+CAIF Core Protocol Layer
+=========================================
+
+CAIF Core layer implements the CAIF protocol as defined by ST-Ericsson.
+It implements the CAIF protocol stack in a layered approach, where
+each layer described in the specification is implemented as a separate layer.
+The architecture is inspired by the design patterns "Protocol Layer" and
+"Protocol Packet".
+
+== CAIF structure ==
+The Core CAIF implementation contains:
+      -	Simple implementation of CAIF.
+      -	Layered architecture (a la Streams), each layer in the CAIF
+	specification is implemented in a separate c-file.
+      -	Clients must call configuration function to add PHY layer.
+      -	Clients must implement CAIF layer to consume/produce
+	CAIF payload with receive and transmit functions.
+      -	Clients must call configuration function to add and connect the
+	Client layer.
+      - When receiving / transmitting CAIF Packets (cfpkt), ownership is passed
+	to the called function (except for framing layers' receive function)
+
+Layered Architecture
+--------------------
+The CAIF protocol can be divided into two parts: Support functions and Protocol
+Implementation. The support functions include:
+
+      - CFPKT CAIF Packet. Implementation of CAIF Protocol Packet. The
+	CAIF Packet has functions for creating, destroying and adding content
+	and for adding/extracting header and trailers to protocol packets.
+
+The CAIF Protocol implementation contains:
+
+      - CFCNFG CAIF Configuration layer. Configures the CAIF Protocol
+	Stack and provides a Client interface for adding Link-Layer and
+	Driver interfaces on top of the CAIF Stack.
+
+      - CFCTRL CAIF Control layer. Encodes and Decodes control messages
+	such as enumeration and channel setup. Also matches request and
+	response messages.
+
+      - CFSERVL General CAIF Service Layer functionality; handles flow
+	control and remote shutdown requests.
+
+      - CFVEI CAIF VEI layer. Handles CAIF AT Channels on VEI (Virtual
+	External Interface). This layer encodes/decodes VEI frames.
+
+      - CFDGML CAIF Datagram layer. Handles CAIF Datagram layer (IP
+	traffic), encodes/decodes Datagram frames.
+
+      - CFMUX CAIF Mux layer. Handles multiplexing between multiple
+	physical bearers and multiple channels such as VEI, Datagram, etc.
+	The MUX keeps track of the existing CAIF Channels and
+	Physical Instances and selects the appropriate instance based
+	on Channel-Id and Physical-ID.
+
+      - CFFRML CAIF Framing layer. Handles Framing i.e. Frame length
+	and frame checksum.
+
+      - CFSERL CAIF Serial layer. Handles concatenation/split of frames
+	into CAIF Frames with correct length.
+
+
+
+		    +---------+
+		    | Config  |
+		    | CFCNFG  |
+		    +---------+
+			 !
+    +---------+	    +---------+	    +---------+
+    |	AT    |	    | Control |	    | Datagram|
+    | CFVEIL  |	    | CFCTRL  |	    | CFDGML  |
+    +---------+	    +---------+	    +---------+
+	   \_____________!______________/
+			 !
+		    +---------+
+		    |	MUX   |
+		    |	      |
+		    +---------+
+		    _____!_____
+		   /	       \
+	    +---------+	    +---------+
+	    | CFFRML  |	    | CFFRML  |
+	    | Framing |	    | Framing |
+	    +---------+	    +---------+
+		 !		!
+	    +---------+	    +---------+
+	    |	      |	    | Serial  |
+	    |	      |	    | CFSERL  |
+	    +---------+	    +---------+
+
+
+In this layered approach the following "rules" apply.
+      - All layers embed the same structure "struct cflayer"
+      - A layer does not depend on any other layer's private data.
+      - Layers are stacked by setting the pointers
+		  layer->up , layer->dn
+      -	In order to send data upwards, each layer should do
+		 layer->up->receive(layer->up, packet);
+      - In order to send data downwards, each layer should do
+		 layer->dn->transmit(layer->dn, packet);
+
+
+CAIF Socket and IP interface
+===========================
+
+The IP interface and CAIF socket API are implemented on top of the
+CAIF Core protocol. The IP Interface and CAIF socket have an instance of
+'struct cflayer', just like the CAIF Core protocol stack.
+Net device and Socket implement the 'receive()' function defined by
+'struct cflayer', just like the rest of the CAIF stack. In this way, transmit and
+receive of packets is handled as by the rest of the layers: the 'dn->transmit()'
+function is called in order to transmit data.
+
+Configuration of Link Layer
+---------------------------
+The Link Layer is implemented as Linux network devices (struct net_device).
+Payload handling and registration is done using standard Linux mechanisms.
+
+The CAIF Protocol relies on a loss-less link layer without implementing
+retransmission. This implies that packet drops must not happen.
+Therefore a flow-control mechanism is implemented where the physical
+interface can initiate flow stop for all CAIF Channels.
diff --git a/Documentation/networking/caif/README b/Documentation/networking/caif/README
new file mode 100644
index 000000000..757ccfaa1
--- /dev/null
+++ b/Documentation/networking/caif/README
@@ -0,0 +1,109 @@
+Copyright (C) ST-Ericsson AB 2010
+Author: Sjur Brendeland/ sjur.brandeland@stericsson.com
+License terms: GNU General Public License (GPL) version 2
+---------------------------------------------------------
+
+=== Start ===
+If you have compiled CAIF for modules do:
+
+$modprobe crc_ccitt
+$modprobe caif
+$modprobe caif_socket
+$modprobe chnl_net
+
+
+=== Preparing the setup with a STE modem ===
+
+If you are working on integration of CAIF you should make sure
+that the kernel is built with module support.
+
+There are some things that need to be tweaked to get the host TTY correctly
+set up to talk to the modem.
+Since the CAIF stack is running in the kernel and we want to use the existing
+TTY, we are installing our physical serial driver as a line discipline above
+the TTY device.
+
+To achieve this we need to install the N_CAIF ldisc from user space.
+The benefit is that we can hook up to any TTY.
+
+The use of Start-of-frame-extension (STX) must also be set as
+module parameter "ser_use_stx".
+
+Normally Frame Checksum is always used on UART, but this is also provided as a
+module parameter "ser_use_fcs".
+
+$ modprobe caif_serial ser_ttyname=/dev/ttyS0 ser_use_stx=yes
+$ ifconfig caif_ttyS0 up
+
+PLEASE NOTE: 	There is a limitation in Android shell.
+		It only accepts one argument to insmod/modprobe!
+
+=== Trouble shooting ===
+
+There are debugfs parameters provided for serial communication.
+/sys/kernel/debug/caif_serial/<tty-name>/
+
+* ser_state:   Prints the bit-mask status where
+  - 0x02 means SENDING, this is a transient state.
+  - 0x10 means FLOW_OFF_SENT, i.e. the previous frame has not been sent
+	and is blocking further send operation. Flow OFF has been propagated
+	to all CAIF Channels using this TTY.
+
+* tty_status: Prints the bit-mask tty status information
+  - 0x01 - tty->warned is on.
+  - 0x02 - tty->low_latency is on.
+  - 0x04 - tty->packed is on.
+  - 0x08 - tty->flow_stopped is on.
+  - 0x10 - tty->hw_stopped is on.
+  - 0x20 - tty->stopped is on.
+
+* last_tx_msg: Binary blob Prints the last transmitted frame.
+	This can be printed with
+	$od --format=x1 /sys/kernel/debug/caif_serial/<tty>/last_rx_msg.
+	The first two tx messages sent look like this. Note: The initial
+	byte 02 is start of frame extension (STX) used for re-syncing
+	upon errors.
+
+  - Enumeration:
+        0000000  02 05 00 00 03 01 d2 02
+                 |  |     |  |  |  |
+                 STX(1)   |  |  |  |
+                    Length(2)|  |  |
+                          Control Channel(1)
+                             Command:Enumeration(1)
+                                Link-ID(1)
+                                    Checksum(2)
+  - Channel Setup:
+        0000000  02 07 00 00 00 21 a1 00 48 df
+                 |  |     |  |  |  |  |  |
+                 STX(1)   |  |  |  |  |  |
+                    Length(2)|  |  |  |  |
+                          Control Channel(1)
+                             Command:Channel Setup(1)
+                                Channel Type(1)
+                                    Priority and Link-ID(1)
+				      Endpoint(1)
+					  Checksum(2)
+
+* last_rx_msg: Prints the last transmitted frame.
+	The RX messages for LinkSetup look almost identical but they have the
+	bit 0x20 set in the command bit, and Channel Setup has added one byte
+	before Checksum containing Channel ID.
+	NOTE: Several CAIF Messages might be concatenated. The maximum debug
+	buffer size is 128 bytes.
+
+== Error Scenarios:
+- last_tx_msg contains channel setup message and last_rx_msg is empty ->
+  The host seems to be able to send over the UART, at least the CAIF ldisc get
+  notified that sending is completed.
+
+- last_tx_msg contains enumeration message and last_rx_msg is empty ->
+  The host is not able to send the message from UART, the tty has not been
+  able to complete the transmit operation.
+
+- if /sys/kernel/debug/caif_serial/<tty>/tty_status is non-zero there
+  might be problems transmitting over UART.
+  E.g. host and modem wiring is not correct you will typically see
+  tty_status = 0x10 (hw_stopped) and ser_state = 0x10 (FLOW_OFF_SENT).
+  You will probably see the enumeration message in last_tx_message
+  and empty last_rx_message.
diff --git a/Documentation/networking/caif/spi_porting.txt b/Documentation/networking/caif/spi_porting.txt
new file mode 100644
index 000000000..9efd0687d
--- /dev/null
+++ b/Documentation/networking/caif/spi_porting.txt
@@ -0,0 +1,208 @@
+- CAIF SPI porting -
+
+- CAIF SPI basics:
+
+Running CAIF over SPI needs some extra setup, owing to the nature of SPI.
+Two extra GPIOs have been added in order to negotiate the transfers
+ between the master and the slave. The minimum requirement for running
+CAIF over SPI is a SPI slave chip and two GPIOs (more details below).
+Please note that running as a slave implies that you need to keep up
+with the master clock. An overrun or underrun event is fatal.
+
+- CAIF SPI framework:
+
+To make porting as easy as possible, the CAIF SPI has been divided in
+two parts. The first part (called the interface part) deals with all
+generic functionality such as length framing, SPI frame negotiation
+and SPI frame delivery and transmission. The other part is the CAIF
+SPI slave device part, which is the module that you have to write if
+you want to run SPI CAIF on a new hardware. This part takes care of
+the physical hardware, both with regard to SPI and to GPIOs.
+
+- Implementing a CAIF SPI device:
+
+	- Functionality provided by the CAIF SPI slave device:
+
+	In order to implement a SPI device you will, as a minimum,
+	need to implement the following
+	functions:
+
+	int (*init_xfer) (struct cfspi_xfer * xfer, struct cfspi_dev *dev):
+
+	This function is called by the CAIF SPI interface to give
+	you a chance to set up your hardware to be ready to receive
+	a stream of data from the master. The xfer structure contains
+	both physical and logical addresses, as well as the total length
+	of the transfer in both directions.The dev parameter can be used
+	to map to different CAIF SPI slave devices.
+
+	void (*sig_xfer) (bool xfer, struct cfspi_dev *dev):
+
+	This function is called by the CAIF SPI interface when the output
+	(SPI_INT) GPIO needs to change state. The boolean value of the xfer
+	variable indicates whether the GPIO should be asserted (HIGH) or
+	deasserted (LOW). The dev parameter can be used to map to different CAIF
+	SPI slave devices.
+
+	- Functionality provided by the CAIF SPI interface:
+
+	void (*ss_cb) (bool assert, struct cfspi_ifc *ifc);
+
+	This function is called by the CAIF SPI slave device in order to
+	signal a change of state of the input GPIO (SS) to the interface.
+	Only active edges are mandatory to be reported.
+	This function can be called from IRQ context (recommended in order
+	not to introduce latency). The ifc parameter should be the pointer
+	returned from the platform probe function in the SPI device structure.
+
+	void (*xfer_done_cb) (struct cfspi_ifc *ifc);
+
+	This function is called by the CAIF SPI slave device in order to
+	report that a transfer is completed. This function should only be
+	called once both the transmission and the reception are completed.
+	This function can be called from IRQ context (recommended in order
+	not to introduce latency). The ifc parameter should be the pointer
+	returned from the platform probe function in the SPI device structure.
+
+	- Connecting the bits and pieces:
+
+		- Filling in the SPI slave device structure:
+
+		Connect the necessary callback functions.
+		Indicate clock speed (used to calculate toggle delays).
+		Chose a suitable name (helps debugging if you use several CAIF
+		SPI slave devices).
+		Assign your private data (can be used to map to your structure).
+
+		- Filling in the SPI slave platform device structure:
+		Add name of driver to connect to ("cfspi_sspi").
+		Assign the SPI slave device structure as platform data.
+
+- Padding:
+
+In order to optimize throughput, a number of SPI padding options are provided.
+Padding can be enabled independently for uplink and downlink transfers.
+Padding can be enabled for the head, the tail and for the total frame size.
+The padding needs to be correctly configured on both sides of the link.
+The padding can be changed via module parameters in cfspi_sspi.c or via
+the sysfs directory of the cfspi_sspi driver (before device registration).
+
+- CAIF SPI device template:
+
+/*
+ *	Copyright (C) ST-Ericsson AB 2010
+ *	Author: Daniel Martensson / Daniel.Martensson@stericsson.com
+ *	License terms: GNU General Public License (GPL), version 2.
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/wait.h>
+#include <linux/interrupt.h>
+#include <linux/dma-mapping.h>
+#include <net/caif/caif_spi.h>
+
+MODULE_LICENSE("GPL");
+
+struct sspi_struct {
+	struct cfspi_dev sdev;
+	struct cfspi_xfer *xfer;
+};
+
+static struct sspi_struct slave;
+static struct platform_device slave_device;
+
+static irqreturn_t sspi_irq(int irq, void *arg)
+{
+	/* You only need to trigger on an edge to the active state of the
+	 * SS signal. Once a edge is detected, the ss_cb() function should be
+	 * called with the parameter assert set to true. It is OK
+	 * (and even advised) to call the ss_cb() function in IRQ context in
+	 * order not to add any delay. */
+
+	return IRQ_HANDLED;
+}
+
+static void sspi_complete(void *context)
+{
+	/* Normally the DMA or the SPI framework will call you back
+	 * in something similar to this. The only thing you need to
+	 * do is to call the xfer_done_cb() function, providing the pointer
+	 * to the CAIF SPI interface. It is OK to call this function
+	 * from IRQ context. */
+}
+
+static int sspi_init_xfer(struct cfspi_xfer *xfer, struct cfspi_dev *dev)
+{
+	/* Store transfer info. For a normal implementation you should
+	 * set up your DMA here and make sure that you are ready to
+	 * receive the data from the master SPI. */
+
+	struct sspi_struct *sspi = (struct sspi_struct *)dev->priv;
+
+	sspi->xfer = xfer;
+
+	return 0;
+}
+
+void sspi_sig_xfer(bool xfer, struct cfspi_dev *dev)
+{
+	/* If xfer is true then you should assert the SPI_INT to indicate to
+	 * the master that you are ready to receive the data from the master
+	 * SPI. If xfer is false then you should de-assert SPI_INT to indicate
+	 * that the transfer is done.
+	 */
+
+	struct sspi_struct *sspi = (struct sspi_struct *)dev->priv;
+}
+
+static void sspi_release(struct device *dev)
+{
+	/*
+	 * Here you should release your SPI device resources.
+	 */
+}
+
+static int __init sspi_init(void)
+{
+	/* Here you should initialize your SPI device by providing the
+	 * necessary functions, clock speed, name and private data. Once
+	 * done, you can register your device with the
+	 * platform_device_register() function. This function will return
+	 * with the CAIF SPI interface initialized. This is probably also
+	 * the place where you should set up your GPIOs, interrupts and SPI
+	 * resources. */
+
+	int res = 0;
+
+	/* Initialize slave device. */
+	slave.sdev.init_xfer = sspi_init_xfer;
+	slave.sdev.sig_xfer = sspi_sig_xfer;
+	slave.sdev.clk_mhz = 13;
+	slave.sdev.priv = &slave;
+	slave.sdev.name = "spi_sspi";
+	slave_device.dev.release = sspi_release;
+
+	/* Initialize platform device. */
+	slave_device.name = "cfspi_sspi";
+	slave_device.dev.platform_data = &slave.sdev;
+
+	/* Register platform device. */
+	res = platform_device_register(&slave_device);
+	if (res) {
+		printk(KERN_WARNING "sspi_init: failed to register dev.\n");
+		return -ENODEV;
+	}
+
+	return res;
+}
+
+static void __exit sspi_exit(void)
+{
+	platform_device_del(&slave_device);
+}
+
+module_init(sspi_init);
+module_exit(sspi_exit);