Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

8 files changed, 1725 insertions, 0 deletions

diff --git a/kernel/Documentation/serial/00-INDEX b/kernel/Documentation/serial/00-INDEX
new file mode 100644
index 000000000..8021a9f29
--- /dev/null
+++ b/kernel/Documentation/serial/00-INDEX
@@ -0,0 +1,16 @@
+00-INDEX
+	- this file.
+README.cycladesZ
+	- info on Cyclades-Z firmware loading.
+driver
+	- intro to the low level serial driver.
+moxa-smartio
+	- file with info on installing/using Moxa multiport serial driver.
+n_gsm.txt
+	- GSM 0710 tty multiplexer howto.
+rocket.txt
+	- info on the Comtrol RocketPort multiport serial driver.
+serial-rs485.txt
+	- info about RS485 structures and support in the kernel.
+tty.txt
+	- guide to the locking policies of the tty layer.
diff --git a/kernel/Documentation/serial/README.cycladesZ b/kernel/Documentation/serial/README.cycladesZ
new file mode 100644
index 000000000..024a69443
--- /dev/null
+++ b/kernel/Documentation/serial/README.cycladesZ
@@ -0,0 +1,8 @@
+
+The Cyclades-Z must have firmware loaded onto the card before it will
+operate.  This operation should be performed during system startup,
+
+The firmware, loader program and the latest device driver code are
+available from Cyclades at
+    ftp://ftp.cyclades.com/pub/cyclades/cyclades-z/linux/
+
diff --git a/kernel/Documentation/serial/driver b/kernel/Documentation/serial/driver
new file mode 100644
index 000000000..c415b0ef4
--- /dev/null
+++ b/kernel/Documentation/serial/driver
@@ -0,0 +1,460 @@
+
+			Low Level Serial API
+			--------------------
+
+
+This document is meant as a brief overview of some aspects of the new serial
+driver.  It is not complete, any questions you have should be directed to
+<rmk@arm.linux.org.uk>
+
+The reference implementation is contained within amba_pl011.c.
+
+
+
+Low Level Serial Hardware Driver
+--------------------------------
+
+The low level serial hardware driver is responsible for supplying port
+information (defined by uart_port) and a set of control methods (defined
+by uart_ops) to the core serial driver.  The low level driver is also
+responsible for handling interrupts for the port, and providing any
+console support.
+
+
+Console Support
+---------------
+
+The serial core provides a few helper functions.  This includes identifing
+the correct port structure (via uart_get_console) and decoding command line
+arguments (uart_parse_options).
+
+There is also a helper function (uart_write_console) which performs a
+character by character write, translating newlines to CRLF sequences.
+Driver writers are recommended to use this function rather than implementing
+their own version.
+
+
+Locking
+-------
+
+It is the responsibility of the low level hardware driver to perform the
+necessary locking using port->lock.  There are some exceptions (which
+are described in the uart_ops listing below.)
+
+There are three locks.  A per-port spinlock, a per-port tmpbuf semaphore,
+and an overall semaphore.
+
+From the core driver perspective, the port->lock locks the following
+data:
+
+	port->mctrl
+	port->icount
+	info->xmit.head (circ->head)
+	info->xmit.tail (circ->tail)
+
+The low level driver is free to use this lock to provide any additional
+locking.
+
+The core driver uses the info->tmpbuf_sem lock to prevent multi-threaded
+access to the info->tmpbuf bouncebuffer used for port writes.
+
+The port_sem semaphore is used to protect against ports being added/
+removed or reconfigured at inappropriate times. Since v2.6.27, this
+semaphore has been the 'mutex' member of the tty_port struct, and
+commonly referred to as the port mutex (or port->mutex).
+
+
+uart_ops
+--------
+
+The uart_ops structure is the main interface between serial_core and the
+hardware specific driver.  It contains all the methods to control the
+hardware.
+
+  tx_empty(port)
+	This function tests whether the transmitter fifo and shifter
+	for the port described by 'port' is empty.  If it is empty,
+	this function should return TIOCSER_TEMT, otherwise return 0.
+	If the port does not support this operation, then it should
+	return TIOCSER_TEMT.
+
+	Locking: none.
+	Interrupts: caller dependent.
+	This call must not sleep
+
+  set_mctrl(port, mctrl)
+	This function sets the modem control lines for port described
+	by 'port' to the state described by mctrl.  The relevant bits
+	of mctrl are:
+		- TIOCM_RTS	RTS signal.
+		- TIOCM_DTR	DTR signal.
+		- TIOCM_OUT1	OUT1 signal.
+		- TIOCM_OUT2	OUT2 signal.
+		- TIOCM_LOOP	Set the port into loopback mode.
+	If the appropriate bit is set, the signal should be driven
+	active.  If the bit is clear, the signal should be driven
+	inactive.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  get_mctrl(port)
+	Returns the current state of modem control inputs.  The state
+	of the outputs should not be returned, since the core keeps
+	track of their state.  The state information should include:
+		- TIOCM_CAR	state of DCD signal
+		- TIOCM_CTS	state of CTS signal
+		- TIOCM_DSR	state of DSR signal
+		- TIOCM_RI	state of RI signal
+	The bit is set if the signal is currently driven active.  If
+	the port does not support CTS, DCD or DSR, the driver should
+	indicate that the signal is permanently active.  If RI is
+	not available, the signal should not be indicated as active.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  stop_tx(port)
+	Stop transmitting characters.  This might be due to the CTS
+	line becoming inactive or the tty layer indicating we want
+	to stop transmission due to an XOFF character.
+
+	The driver should stop transmitting characters as soon as
+	possible.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  start_tx(port)
+	Start transmitting characters.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  send_xchar(port,ch)
+	Transmit a high priority character, even if the port is stopped.
+	This is used to implement XON/XOFF flow control and tcflow().  If
+	the serial driver does not implement this function, the tty core
+	will append the character to the circular buffer and then call
+	start_tx() / stop_tx() to flush the data out.
+
+	Do not transmit if ch == '\0' (__DISABLED_CHAR).
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  stop_rx(port)
+	Stop receiving characters; the port is in the process of
+	being closed.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  enable_ms(port)
+	Enable the modem status interrupts.
+
+	This method may be called multiple times.  Modem status
+	interrupts should be disabled when the shutdown method is
+	called.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  break_ctl(port,ctl)
+	Control the transmission of a break signal.  If ctl is
+	nonzero, the break signal should be transmitted.  The signal
+	should be terminated when another call is made with a zero
+	ctl.
+
+	Locking: none.
+	Interrupts: caller dependent.
+	This call must not sleep
+
+  startup(port)
+	Grab any interrupt resources and initialise any low level driver
+	state.  Enable the port for reception.  It should not activate
+	RTS nor DTR; this will be done via a separate call to set_mctrl.
+
+	This method will only be called when the port is initially opened.
+
+	Locking: port_sem taken.
+	Interrupts: globally disabled.
+
+  shutdown(port)
+	Disable the port, disable any break condition that may be in
+	effect, and free any interrupt resources.  It should not disable
+	RTS nor DTR; this will have already been done via a separate
+	call to set_mctrl.
+
+	Drivers must not access port->info once this call has completed.
+
+	This method will only be called when there are no more users of
+	this port.
+
+	Locking: port_sem taken.
+	Interrupts: caller dependent.
+
+  flush_buffer(port)
+	Flush any write buffers, reset any DMA state and stop any
+	ongoing DMA transfers.
+
+	This will be called whenever the port->info->xmit circular
+	buffer is cleared.
+
+	Locking: port->lock taken.
+	Interrupts: locally disabled.
+	This call must not sleep
+
+  set_termios(port,termios,oldtermios)
+	Change the port parameters, including word length, parity, stop
+	bits.  Update read_status_mask and ignore_status_mask to indicate
+	the types of events we are interested in receiving.  Relevant
+	termios->c_cflag bits are:
+		CSIZE	- word size
+		CSTOPB	- 2 stop bits
+		PARENB	- parity enable
+		PARODD	- odd parity (when PARENB is in force)
+		CREAD	- enable reception of characters (if not set,
+			  still receive characters from the port, but
+			  throw them away.
+		CRTSCTS	- if set, enable CTS status change reporting
+		CLOCAL	- if not set, enable modem status change
+			  reporting.
+	Relevant termios->c_iflag bits are:
+		INPCK	- enable frame and parity error events to be
+			  passed to the TTY layer.
+		BRKINT
+		PARMRK	- both of these enable break events to be
+			  passed to the TTY layer.
+
+		IGNPAR	- ignore parity and framing errors
+		IGNBRK	- ignore break errors,  If IGNPAR is also
+			  set, ignore overrun errors as well.
+	The interaction of the iflag bits is as follows (parity error
+	given as an example):
+	Parity error	INPCK	IGNPAR
+	n/a		0	n/a	character received, marked as
+					TTY_NORMAL
+	None		1	n/a	character received, marked as
+					TTY_NORMAL
+	Yes		1	0	character received, marked as
+					TTY_PARITY
+	Yes		1	1	character discarded
+
+	Other flags may be used (eg, xon/xoff characters) if your
+	hardware supports hardware "soft" flow control.
+
+	Locking: caller holds port->mutex
+	Interrupts: caller dependent.
+	This call must not sleep
+
+  pm(port,state,oldstate)
+	Perform any power management related activities on the specified
+	port.  State indicates the new state (defined by
+	enum uart_pm_state), oldstate indicates the previous state.
+
+	This function should not be used to grab any resources.
+
+	This will be called when the port is initially opened and finally
+	closed, except when the port is also the system console.  This
+	will occur even if CONFIG_PM is not set.
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  type(port)
+	Return a pointer to a string constant describing the specified
+	port, or return NULL, in which case the string 'unknown' is
+	substituted.
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  release_port(port)
+	Release any memory and IO region resources currently in use by
+	the port.
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  request_port(port)
+	Request any memory and IO region resources required by the port.
+	If any fail, no resources should be registered when this function
+	returns, and it should return -EBUSY on failure.
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  config_port(port,type)
+	Perform any autoconfiguration steps required for the port.  `type`
+	contains a bit mask of the required configuration.  UART_CONFIG_TYPE
+	indicates that the port requires detection and identification.
+	port->type should be set to the type found, or PORT_UNKNOWN if
+	no port was detected.
+
+	UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal,
+	which should be probed using standard kernel autoprobing techniques.
+	This is not necessary on platforms where ports have interrupts
+	internally hard wired (eg, system on a chip implementations).
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  verify_port(port,serinfo)
+	Verify the new serial port information contained within serinfo is
+	suitable for this port type.
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  ioctl(port,cmd,arg)
+	Perform any port specific IOCTLs.  IOCTL commands must be defined
+	using the standard numbering system found in <asm/ioctl.h>
+
+	Locking: none.
+	Interrupts: caller dependent.
+
+  poll_init(port)
+	Called by kgdb to perform the minimal hardware initialization needed
+	to support poll_put_char() and poll_get_char().  Unlike ->startup()
+	this should not request interrupts.
+
+	Locking: tty_mutex and tty_port->mutex taken.
+	Interrupts: n/a.
+
+  poll_put_char(port,ch)
+	Called by kgdb to write a single character directly to the serial
+	port.  It can and should block until there is space in the TX FIFO.
+
+	Locking: none.
+	Interrupts: caller dependent.
+	This call must not sleep
+
+  poll_get_char(port)
+	Called by kgdb to read a single character directly from the serial
+	port.  If data is available, it should be returned; otherwise
+	the function should return NO_POLL_CHAR immediately.
+
+	Locking: none.
+	Interrupts: caller dependent.
+	This call must not sleep
+
+Other functions
+---------------
+
+uart_update_timeout(port,cflag,baud)
+	Update the FIFO drain timeout, port->timeout, according to the
+	number of bits, parity, stop bits and baud rate.
+
+	Locking: caller is expected to take port->lock
+	Interrupts: n/a
+
+uart_get_baud_rate(port,termios,old,min,max)
+	Return the numeric baud rate for the specified termios, taking
+	account of the special 38400 baud "kludge".  The B0 baud rate
+	is mapped to 9600 baud.
+
+	If the baud rate is not within min..max, then if old is non-NULL,
+	the original baud rate will be tried.  If that exceeds the
+	min..max constraint, 9600 baud will be returned.  termios will
+	be updated to the baud rate in use.
+
+	Note: min..max must always allow 9600 baud to be selected.
+
+	Locking: caller dependent.
+	Interrupts: n/a
+
+uart_get_divisor(port,baud)
+	Return the divsor (baud_base / baud) for the specified baud
+	rate, appropriately rounded.
+
+	If 38400 baud and custom divisor is selected, return the
+	custom divisor instead.
+
+	Locking: caller dependent.
+	Interrupts: n/a
+
+uart_match_port(port1,port2)
+	This utility function can be used to determine whether two
+	uart_port structures describe the same port.
+
+	Locking: n/a
+	Interrupts: n/a
+
+uart_write_wakeup(port)
+	A driver is expected to call this function when the number of
+	characters in the transmit buffer have dropped below a threshold.
+
+	Locking: port->lock should be held.
+	Interrupts: n/a
+
+uart_register_driver(drv)
+	Register a uart driver with the core driver.  We in turn register
+	with the tty layer, and initialise the core driver per-port state.
+
+	drv->port should be NULL, and the per-port structures should be
+	registered using uart_add_one_port after this call has succeeded.
+
+	Locking: none
+	Interrupts: enabled
+
+uart_unregister_driver()
+	Remove all references to a driver from the core driver.  The low
+	level driver must have removed all its ports via the
+	uart_remove_one_port() if it registered them with uart_add_one_port().
+
+	Locking: none
+	Interrupts: enabled
+
+uart_suspend_port()
+
+uart_resume_port()
+
+uart_add_one_port()
+
+uart_remove_one_port()
+
+Other notes
+-----------
+
+It is intended some day to drop the 'unused' entries from uart_port, and
+allow low level drivers to register their own individual uart_port's with
+the core.  This will allow drivers to use uart_port as a pointer to a
+structure containing both the uart_port entry with their own extensions,
+thus:
+
+	struct my_port {
+		struct uart_port	port;
+		int			my_stuff;
+	};
+
+Modem control lines via GPIO
+----------------------------
+
+Some helpers are provided in order to set/get modem control lines via GPIO.
+
+mctrl_gpio_init(dev, idx):
+	This will get the {cts,rts,...}-gpios from device tree if they are
+	present and request them, set direction etc, and return an
+	allocated structure. devm_* functions are used, so there's no need
+	to call mctrl_gpio_free().
+
+mctrl_gpio_free(dev, gpios):
+	This will free the requested gpios in mctrl_gpio_init().
+	As devm_* function are used, there's generally no need to call
+	this function.
+
+mctrl_gpio_to_gpiod(gpios, gidx)
+	This returns the gpio structure associated to the modem line index.
+
+mctrl_gpio_set(gpios, mctrl):
+	This will sets the gpios according to the mctrl state.
+
+mctrl_gpio_get(gpios, mctrl):
+	This will update mctrl with the gpios values.
diff --git a/kernel/Documentation/serial/moxa-smartio b/kernel/Documentation/serial/moxa-smartio
new file mode 100644
index 000000000..5d2a33be0
--- /dev/null
+++ b/kernel/Documentation/serial/moxa-smartio
@@ -0,0 +1,523 @@
+=============================================================================
+          MOXA Smartio/Industio Family Device Driver Installation Guide
+		    for Linux Kernel 2.4.x, 2.6.x
+	       Copyright (C) 2008, Moxa Inc.
+=============================================================================
+Date: 01/21/2008
+
+Content
+
+1. Introduction
+2. System Requirement
+3. Installation
+   3.1 Hardware installation
+   3.2 Driver files
+   3.3 Device naming convention
+   3.4 Module driver configuration
+   3.5 Static driver configuration for Linux kernel 2.4.x and 2.6.x.
+   3.6 Custom configuration
+   3.7 Verify driver installation
+4. Utilities
+5. Setserial
+6. Troubleshooting
+
+-----------------------------------------------------------------------------
+1. Introduction
+
+   The Smartio/Industio/UPCI family Linux driver supports following multiport
+   boards.
+
+    - 2 ports multiport board
+	CP-102U, CP-102UL, CP-102UF
+	CP-132U-I, CP-132UL,
+	CP-132, CP-132I, CP132S, CP-132IS,
+	CI-132, CI-132I, CI-132IS,
+	(C102H, C102HI, C102HIS, C102P, CP-102, CP-102S)
+
+    - 4 ports multiport board
+	CP-104EL,
+	CP-104UL, CP-104JU,
+	CP-134U, CP-134U-I,
+	C104H/PCI, C104HS/PCI,
+	CP-114, CP-114I, CP-114S, CP-114IS, CP-114UL,
+	C104H, C104HS,
+	CI-104J, CI-104JS,
+	CI-134, CI-134I, CI-134IS,
+	(C114HI, CT-114I, C104P)
+	POS-104UL,
+	CB-114,
+	CB-134I
+
+    - 8 ports multiport board
+	CP-118EL, CP-168EL,
+	CP-118U, CP-168U,
+	C168H/PCI,
+	C168H, C168HS,
+	(C168P),
+	CB-108
+
+   This driver and installation procedure have been developed upon Linux Kernel
+   2.4.x and 2.6.x. This driver supports Intel x86 hardware platform. In order
+   to maintain compatibility, this version has also been properly tested with
+   RedHat, Mandrake, Fedora and S.u.S.E Linux. However, if compatibility problem
+   occurs, please contact Moxa at support@moxa.com.tw.
+
+   In addition to device driver, useful utilities are also provided in this
+   version. They are
+    - msdiag     Diagnostic program for displaying installed Moxa
+                 Smartio/Industio boards.
+    - msmon      Monitor program to observe data count and line status signals.
+    - msterm     A simple terminal program which is useful in testing serial
+	         ports.
+    - io-irq.exe Configuration program to setup ISA boards. Please note that
+                 this program can only be executed under DOS.
+
+   All the drivers and utilities are published in form of source code under
+   GNU General Public License in this version. Please refer to GNU General
+   Public License announcement in each source code file for more detail.
+
+   In Moxa's Web sites, you may always find latest driver at http://www.moxa.com/.
+
+   This version of driver can be installed as Loadable Module (Module driver)
+   or built-in into kernel (Static driver). You may refer to following
+   installation procedure for suitable one. Before you install the driver,
+   please refer to hardware installation procedure in the User's Manual.
+
+   We assume the user should be familiar with following documents.
+   - Serial-HOWTO
+   - Kernel-HOWTO
+
+-----------------------------------------------------------------------------
+2. System Requirement
+   - Hardware platform: Intel x86 machine
+   - Kernel version: 2.4.x or 2.6.x
+   - gcc version 2.72 or later
+   - Maximum 4 boards can be installed in combination
+
+-----------------------------------------------------------------------------
+3. Installation
+
+   3.1 Hardware installation
+   3.2 Driver files
+   3.3 Device naming convention
+   3.4 Module driver configuration
+   3.5 Static driver configuration for Linux kernel 2.4.x, 2.6.x.
+   3.6 Custom configuration
+   3.7 Verify driver installation
+
+
+   3.1 Hardware installation
+
+       There are two types of buses, ISA and PCI, for Smartio/Industio
+       family multiport board.
+
+       ISA board
+       ---------
+       You'll have to configure CAP address, I/O address, Interrupt Vector
+       as well as IRQ before installing this driver. Please refer to hardware
+       installation procedure in User's Manual before proceed any further.
+       Please make sure the JP1 is open after the ISA board is set properly.
+
+       PCI/UPCI board
+       --------------
+       You may need to adjust IRQ usage in BIOS to avoid from IRQ conflict
+       with other ISA devices. Please refer to hardware installation
+       procedure in User's Manual in advance.
+
+       PCI IRQ Sharing
+       -----------
+       Each port within the same multiport board shares the same IRQ. Up to
+       4 Moxa Smartio/Industio PCI Family multiport boards can be installed
+       together on one system and they can share the same IRQ.
+
+
+   3.2 Driver files
+
+       The driver file may be obtained from ftp, CD-ROM or floppy disk. The
+       first step, anyway, is to copy driver file "mxser.tgz" into specified
+       directory. e.g. /moxa. The execute commands as below.
+
+       # cd /
+       # mkdir moxa
+       # cd /moxa
+       # tar xvf /dev/fd0
+
+       or
+
+       # cd /
+       # mkdir moxa
+       # cd /moxa
+       # cp /mnt/cdrom/<driver directory>/mxser.tgz .
+       # tar xvfz mxser.tgz
+
+
+   3.3 Device naming convention
+
+       You may find all the driver and utilities files in /moxa/mxser.
+       Following installation procedure depends on the model you'd like to
+       run the driver. If you prefer module driver, please refer to 3.4.
+       If static driver is required, please refer to 3.5.
+
+       Dialin and callout port
+       -----------------------
+       This driver remains traditional serial device properties. There are
+       two special file name for each serial port. One is dial-in port
+       which is named "ttyMxx". For callout port, the naming convention
+       is "cumxx".
+
+       Device naming when more than 2 boards installed
+       -----------------------------------------------
+       Naming convention for each Smartio/Industio multiport board is
+       pre-defined as below.
+
+       Board Num.	 Dial-in Port	      Callout port
+       1st board	ttyM0  - ttyM7	      cum0  - cum7
+       2nd board	ttyM8  - ttyM15       cum8  - cum15
+       3rd board	ttyM16 - ttyM23       cum16 - cum23
+       4th board	ttyM24 - ttym31       cum24 - cum31
+
+
+       !!!!!!!!!!!!!!!!!!!! NOTE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+       Under Kernel 2.6 the cum Device is Obsolete. So use ttyM*
+       device instead.
+       !!!!!!!!!!!!!!!!!!!! NOTE !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+       Board sequence
+       --------------
+       This driver will activate ISA boards according to the parameter set
+       in the driver. After all specified ISA board activated, PCI board
+       will be installed in the system automatically driven.
+       Therefore the board number is sorted by the CAP address of ISA boards.
+       For PCI boards, their sequence will be after ISA boards and C168H/PCI
+       has higher priority than C104H/PCI boards.
+
+   3.4 Module driver configuration
+       Module driver is easiest way to install. If you prefer static driver
+       installation, please skip this paragraph.
+
+
+       ------------- Prepare to use the MOXA driver--------------------
+       3.4.1 Create tty device with correct major number
+          Before using MOXA driver, your system must have the tty devices
+          which are created with driver's major number. We offer one shell
+          script "msmknod" to simplify the procedure.
+          This step is only needed to be executed once. But you still
+          need to do this procedure when:
+          a. You change the driver's major number. Please refer the "3.7"
+             section.
+          b. Your total installed MOXA boards number is changed. Maybe you
+             add/delete one MOXA board.
+          c. You want to change the tty name. This needs to modify the
+             shell script "msmknod"
+
+          The procedure is:
+	  # cd /moxa/mxser/driver
+	  # ./msmknod
+
+          This shell script will require the major number for dial-in
+          device and callout device to create tty device. You also need
+          to specify the total installed MOXA board number. Default major
+          numbers for dial-in device and callout device are 30, 35. If
+          you need to change to other number, please refer section "3.7"
+          for more detailed procedure.
+          Msmknod will delete any special files occupying the same device
+          naming.
+
+       3.4.2 Build the MOXA driver and utilities
+          Before using the MOXA driver and utilities, you need compile the
+          all the source code. This step is only need to be executed once.
+          But you still re-compile the source code if you modify the source
+          code. For example, if you change the driver's major number (see
+          "3.7" section), then you need to do this step again.
+
+          Find "Makefile" in /moxa/mxser, then run
+
+	  # make clean; make install
+
+          !!!!!!!!!! NOTE !!!!!!!!!!!!!!!!!
+	  For Red Hat 9, Red Hat Enterprise Linux AS3/ES3/WS3 & Fedora Core1:
+	  # make clean; make installsp1
+
+	  For Red Hat Enterprise Linux AS4/ES4/WS4:
+	  # make clean; make installsp2
+          !!!!!!!!!! NOTE !!!!!!!!!!!!!!!!!
+
+	  The driver files "mxser.o" and utilities will be properly compiled
+	  and copied to system directories respectively.
+
+       ------------- Load MOXA driver--------------------
+       3.4.3 Load the MOXA driver
+
+	  # modprobe mxser <argument>
+
+	  will activate the module driver. You may run "lsmod" to check
+	  if "mxser" is activated. If the MOXA board is ISA board, the
+          <argument> is needed. Please refer to section "3.4.5" for more
+          information.
+
+
+       ------------- Load MOXA driver on boot --------------------
+       3.4.4 For the above description, you may manually execute
+          "modprobe mxser" to activate this driver and run
+	  "rmmod mxser" to remove it.
+          However, it's better to have a boot time configuration to
+          eliminate manual operation. Boot time configuration can be
+          achieved by rc file. We offer one "rc.mxser" file to simplify
+          the procedure under "moxa/mxser/driver".
+
+          But if you use ISA board, please modify the "modprobe ..." command
+          to add the argument (see "3.4.5" section). After modifying the
+          rc.mxser, please try to execute "/moxa/mxser/driver/rc.mxser"
+          manually to make sure the modification is ok. If any error
+          encountered, please try to modify again. If the modification is
+          completed, follow the below step.
+
+	  Run following command for setting rc files.
+
+	  # cd /moxa/mxser/driver
+	  # cp ./rc.mxser /etc/rc.d
+	  # cd /etc/rc.d
+
+	  Check "rc.serial" is existed or not. If "rc.serial" doesn't exist,
+	  create it by vi, run "chmod 755 rc.serial" to change the permission.
+	  Add "/etc/rc.d/rc.mxser" in last line,
+
+          Reboot and check if moxa.o activated by "lsmod" command.
+
+       3.4.5. If you'd like to drive Smartio/Industio ISA boards in the system,
+          you'll have to add parameter to specify CAP address of given
+	  board while activating "mxser.o". The format for parameters are
+	  as follows.
+
+	  modprobe mxser ioaddr=0x???,0x???,0x???,0x???
+				|      |     |	  |
+				|      |     |	  +- 4th ISA board
+				|      |     +------ 3rd ISA board
+				|      +------------ 2nd ISA board
+				+------------------- 1st ISA board
+
+   3.5 Static driver configuration for Linux kernel 2.4.x and 2.6.x
+
+       Note: To use static driver, you must install the linux kernel
+             source package.
+
+       3.5.1 Backup the built-in driver in the kernel.
+          # cd /usr/src/linux/drivers/char
+          # mv mxser.c mxser.c.old
+
+          For Red Hat 7.x user, you need to create link:
+          # cd /usr/src
+          # ln -s linux-2.4 linux
+
+       3.5.2 Create link
+	  # cd /usr/src/linux/drivers/char
+	  # ln -s /moxa/mxser/driver/mxser.c mxser.c
+
+       3.5.3 Add CAP address list for ISA boards. For PCI boards user,
+          please skip this step.
+
+	  In module mode, the CAP address for ISA board is given by
+	  parameter. In static driver configuration, you'll have to
+	  assign it within driver's source code. If you will not
+	  install any ISA boards, you may skip to next portion.
+	  The instructions to modify driver source code are as
+	  below.
+	  a. # cd /moxa/mxser/driver
+	     # vi mxser.c
+	  b. Find the array mxserBoardCAP[] as below.
+
+	     static int mxserBoardCAP[]
+	     = {0x00, 0x00, 0x00, 0x00};
+
+	  c. Change the address within this array using vi. For
+	     example, to driver 2 ISA boards with CAP address
+	     0x280 and 0x180 as 1st and 2nd board. Just to change
+	     the source code as follows.
+
+	     static int mxserBoardCAP[]
+	     = {0x280, 0x180, 0x00, 0x00};
+
+       3.5.4 Setup kernel configuration
+
+          Configure the kernel:
+
+            # cd /usr/src/linux
+            # make menuconfig
+
+          You will go into a menu-driven system. Please select [Character
+          devices][Non-standard serial port support], enable the [Moxa
+          SmartIO support] driver with "[*]" for built-in (not "[M]"), then
+          select [Exit] to exit this program.
+
+       3.5.5 Rebuild kernel
+	  The following are for Linux kernel rebuilding, for your
+          reference only.
+	  For appropriate details, please refer to the Linux document.
+
+	   a. cd /usr/src/linux
+	   b. make clean	     /* take a few minutes */
+	   c. make dep		     /* take a few minutes */
+	   d. make bzImage	     /* take probably 10-20 minutes */
+	   e. make install	     /* copy boot image to correct position */
+	   f. Please make sure the boot kernel (vmlinuz) is in the
+	      correct position.
+	   g. If you use 'lilo' utility, you should check /etc/lilo.conf
+	      'image' item specified the path which is the 'vmlinuz' path,
+	      or you will load wrong (or old) boot kernel image (vmlinuz).
+	      After checking /etc/lilo.conf, please run "lilo".
+
+	  Note that if the result of "make bzImage" is ERROR, then you have to
+	  go back to Linux configuration Setup. Type "make menuconfig" in
+          directory /usr/src/linux.
+
+
+       3.5.6 Make tty device and special file
+          # cd /moxa/mxser/driver
+          # ./msmknod
+
+       3.5.7 Make utility
+	  # cd /moxa/mxser/utility
+	  # make clean; make install
+
+       3.5.8 Reboot
+
+
+
+   3.6 Custom configuration
+       Although this driver already provides you default configuration, you
+       still can change the device name and major number. The instruction to
+       change these parameters are shown as below.
+
+       Change Device name
+       ------------------
+       If you'd like to use other device names instead of default naming
+       convention, all you have to do is to modify the internal code
+       within the shell script "msmknod". First, you have to open "msmknod"
+       by vi. Locate each line contains "ttyM" and "cum" and change them
+       to the device name you desired. "msmknod" creates the device names
+       you need next time executed.
+
+       Change Major number
+       -------------------
+       If major number 30 and 35 had been occupied, you may have to select
+       2 free major numbers for this driver. There are 3 steps to change
+       major numbers.
+
+       3.6.1 Find free major numbers
+	  In /proc/devices, you may find all the major numbers occupied
+	  in the system. Please select 2 major numbers that are available.
+	  e.g. 40, 45.
+       3.6.2 Create special files
+	  Run /moxa/mxser/driver/msmknod to create special files with
+	  specified major numbers.
+       3.6.3 Modify driver with new major number
+	  Run vi to open /moxa/mxser/driver/mxser.c. Locate the line
+	  contains "MXSERMAJOR". Change the content as below.
+	  #define	  MXSERMAJOR		  40
+	  #define	  MXSERCUMAJOR		  45
+       3.6.4 Run "make clean; make install" in /moxa/mxser/driver.
+
+   3.7 Verify driver installation
+       You may refer to /var/log/messages to check the latest status
+       log reported by this driver whenever it's activated.
+
+-----------------------------------------------------------------------------
+4. Utilities
+   There are 3 utilities contained in this driver. They are msdiag, msmon and
+   msterm. These 3 utilities are released in form of source code. They should
+   be compiled into executable file and copied into /usr/bin.
+
+   Before using these utilities, please load driver (refer 3.4 & 3.5) and
+   make sure you had run the "msmknod" utility.
+
+   msdiag - Diagnostic
+   --------------------
+   This utility provides the function to display what Moxa Smartio/Industio
+   board found by driver in the system.
+
+   msmon - Port Monitoring
+   -----------------------
+   This utility gives the user a quick view about all the MOXA ports'
+   activities. One can easily learn each port's total received/transmitted
+   (Rx/Tx) character count since the time when the monitoring is started.
+   Rx/Tx throughputs per second are also reported in interval basis (e.g.
+   the last 5 seconds) and in average basis (since the time the monitoring
+   is started). You can reset all ports' count by <HOME> key. <+> <->
+   (plus/minus) keys to change the displaying time interval. Press <ENTER>
+   on the port, that cursor stay, to view the port's communication
+   parameters, signal status, and input/output queue.
+
+   msterm - Terminal Emulation
+   ---------------------------
+   This utility provides data sending and receiving ability of all tty ports,
+   especially for MOXA ports. It is quite useful for testing simple
+   application, for example, sending AT command to a modem connected to the
+   port or used as a terminal for login purpose. Note that this is only a
+   dumb terminal emulation without handling full screen operation.
+
+-----------------------------------------------------------------------------
+5. Setserial
+
+   Supported Setserial parameters are listed as below.
+
+   uart		  set UART type(16450-->disable FIFO, 16550A-->enable FIFO)
+   close_delay	  set the amount of time(in 1/100 of a second) that DTR
+		  should be kept low while being closed.
+   closing_wait   set the amount of time(in 1/100 of a second) that the
+		  serial port should wait for data to be drained while
+		  being closed, before the receiver is disable.
+   spd_hi	  Use  57.6kb  when  the application requests 38.4kb.
+   spd_vhi	  Use  115.2kb	when  the application requests 38.4kb.
+   spd_shi	  Use  230.4kb	when  the application requests 38.4kb.
+   spd_warp	  Use  460.8kb	when  the application requests 38.4kb.
+   spd_normal	  Use  38.4kb  when  the application requests 38.4kb.
+   spd_cust	  Use  the custom divisor to set the speed when  the
+		  application requests 38.4kb.
+   divisor	  This option set the custom division.
+   baud_base	  This option set the base baud rate.
+
+-----------------------------------------------------------------------------
+6. Troubleshooting
+
+   The boot time error messages and solutions are stated as clearly as
+   possible. If all the possible solutions fail, please contact our technical
+   support team to get more help.
+
+
+   Error msg: More than 4 Moxa Smartio/Industio family boards found. Fifth board
+              and after are ignored.
+   Solution:
+   To avoid this problem, please unplug fifth and after board, because Moxa
+   driver supports up to 4 boards.
+
+   Error msg: Request_irq fail, IRQ(?) may be conflict with another device.
+   Solution:
+   Other PCI or ISA devices occupy the assigned IRQ. If you are not sure
+   which device causes the situation, please check /proc/interrupts to find
+   free IRQ and simply change another free IRQ for Moxa board.
+
+   Error msg: Board #: C1xx Series(CAP=xxx) interrupt number invalid.
+   Solution:
+   Each port within the same multiport board shares the same IRQ. Please set
+   one IRQ (IRQ doesn't equal to zero) for one Moxa board.
+
+   Error msg: No interrupt vector be set for Moxa ISA board(CAP=xxx).
+   Solution:
+   Moxa ISA board needs an interrupt vector.Please refer to user's manual
+   "Hardware Installation" chapter to set interrupt vector.
+
+   Error msg: Couldn't install MOXA Smartio/Industio family driver!
+   Solution:
+   Load Moxa driver fail, the major number may conflict with other devices.
+   Please refer to previous section 3.7 to change a free major number for
+   Moxa driver.
+
+   Error msg: Couldn't install MOXA Smartio/Industio family callout driver!
+   Solution:
+   Load Moxa callout driver fail, the callout device major number may
+   conflict with other devices. Please refer to previous section 3.7 to
+   change a free callout device major number for Moxa driver.
+
+
+-----------------------------------------------------------------------------
+
diff --git a/kernel/Documentation/serial/n_gsm.txt b/kernel/Documentation/serial/n_gsm.txt
new file mode 100644
index 000000000..a5d91126a
--- /dev/null
+++ b/kernel/Documentation/serial/n_gsm.txt
@@ -0,0 +1,89 @@
+n_gsm.c GSM 0710 tty multiplexor HOWTO
+===================================================
+
+This line discipline implements the GSM 07.10 multiplexing protocol
+detailed in the following 3GPP document :
+http://www.3gpp.org/ftp/Specs/archive/07_series/07.10/0710-720.zip
+
+This document give some hints on how to use this driver with GPRS and 3G
+modems connected to a physical serial port.
+
+How to use it
+-------------
+1- initialize the modem in 0710 mux mode (usually AT+CMUX= command) through
+its serial port. Depending on the modem used, you can pass more or less
+parameters to this command,
+2- switch the serial line to using the n_gsm line discipline by using
+TIOCSETD ioctl,
+3- configure the mux using GSMIOC_GETCONF / GSMIOC_SETCONF ioctl,
+
+Major parts of the initialization program :
+(a good starting point is util-linux-ng/sys-utils/ldattach.c)
+#include <linux/gsmmux.h>
+#define N_GSM0710	21	/* GSM 0710 Mux */
+#define DEFAULT_SPEED	B115200
+#define SERIAL_PORT	/dev/ttyS0
+
+	int ldisc = N_GSM0710;
+	struct gsm_config c;
+	struct termios configuration;
+
+	/* open the serial port connected to the modem */
+	fd = open(SERIAL_PORT, O_RDWR | O_NOCTTY | O_NDELAY);
+
+	/* configure the serial port : speed, flow control ... */
+
+	/* send the AT commands to switch the modem to CMUX mode
+	   and check that it's successful (should return OK) */
+	write(fd, "AT+CMUX=0\r", 10);
+
+	/* experience showed that some modems need some time before
+	   being able to answer to the first MUX packet so a delay
+	   may be needed here in some case */
+	sleep(3);
+
+	/* use n_gsm line discipline */
+	ioctl(fd, TIOCSETD, &ldisc);
+
+	/* get n_gsm configuration */
+	ioctl(fd, GSMIOC_GETCONF, &c);
+	/* we are initiator and need encoding 0 (basic) */
+	c.initiator = 1;
+	c.encapsulation = 0;
+	/* our modem defaults to a maximum size of 127 bytes */
+	c.mru = 127;
+	c.mtu = 127;
+	/* set the new configuration */
+	ioctl(fd, GSMIOC_SETCONF, &c);
+
+	/* and wait for ever to keep the line discipline enabled */
+	daemon(0,0);
+	pause();
+
+4- create the devices corresponding to the "virtual" serial ports (take care,
+each modem has its configuration and some DLC have dedicated functions,
+for example GPS), starting with minor 1 (DLC0 is reserved for the management
+of the mux)
+
+MAJOR=`cat /proc/devices |grep gsmtty | awk '{print $1}`
+for i in `seq 1 4`; do
+	mknod /dev/ttygsm$i c $MAJOR $i
+done
+
+5- use these devices as plain serial ports.
+for example, it's possible :
+- and to use gnokii to send / receive SMS on ttygsm1
+- to use ppp to establish a datalink on ttygsm2
+
+6- first close all virtual ports before closing the physical port.
+
+Additional Documentation
+------------------------
+More practical details on the protocol and how it's supported by industrial
+modems can be found in the following documents :
+http://www.telit.com/module/infopool/download.php?id=616
+http://www.u-blox.com/images/downloads/Product_Docs/LEON-G100-G200-MuxImplementation_ApplicationNote_%28GSM%20G1-CS-10002%29.pdf
+http://www.sierrawireless.com/Support/Downloads/AirPrime/WMP_Series/~/media/Support_Downloads/AirPrime/Application_notes/CMUX_Feature_Application_Note-Rev004.ashx
+http://wm.sim.com/sim/News/photo/2010721161442.pdf
+
+11-03-08 - Eric Bénard - <eric@eukrea.com>
diff --git a/kernel/Documentation/serial/rocket.txt b/kernel/Documentation/serial/rocket.txt
new file mode 100644
index 000000000..60b039891
--- /dev/null
+++ b/kernel/Documentation/serial/rocket.txt
@@ -0,0 +1,189 @@
+Comtrol(tm) RocketPort(R)/RocketModem(TM) Series 
+Device Driver for the Linux Operating System
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+PRODUCT OVERVIEW
+----------------
+
+This driver provides a loadable kernel driver for the Comtrol RocketPort
+and RocketModem PCI boards. These boards provide, 2, 4, 8, 16, or 32 
+high-speed serial ports or modems.  This driver supports up to a combination
+of four RocketPort or RocketModems boards in one machine simultaneously.
+This file assumes that you are using the RocketPort driver which is
+integrated into the kernel sources.  
+
+The driver can also be installed as an external module using the usual 
+"make;make install" routine.  This external module driver, obtainable 
+from the Comtrol website listed below, is useful for updating the driver
+or installing it into kernels which do not have the driver configured
+into them.  Installations instructions for the external module
+are in the included README and HW_INSTALL files.
+
+RocketPort ISA and RocketModem II PCI boards currently are only supported by
+this driver in module form.
+
+The RocketPort ISA board requires I/O ports to be configured by the DIP
+switches on the board.  See the section "ISA Rocketport Boards" below for
+information on how to set the DIP switches.
+
+You pass the I/O port to the driver using the following module parameters:
+
+board1 :	I/O port for the first ISA board
+board2 :	I/O port for the second ISA board
+board3 :	I/O port for the third ISA board
+board4 :	I/O port for the fourth ISA board
+
+There is a set of utilities and scripts provided with the external driver
+( downloadable from http://www.comtrol.com ) that ease the configuration and
+setup of the ISA cards.
+
+The RocketModem II PCI boards require firmware to be loaded into the card
+before it will function.  The driver has only been tested as a module for this
+board.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+INSTALLATION PROCEDURES
+-----------------------
+
+RocketPort/RocketModem PCI cards require no driver configuration, they are 
+automatically detected and configured.
+
+The RocketPort driver can be installed as a module (recommended) or built 
+into the kernel. This is selected, as for other drivers, through the `make config`
+command from the root of the Linux source tree during the kernel build process. 
+
+The RocketPort/RocketModem serial ports installed by this driver are assigned
+device major number 46, and will be named /dev/ttyRx, where x is the port number 
+starting at zero (ex. /dev/ttyR0, /devttyR1, ...).  If you have multiple cards
+installed in the system, the mapping of port names to serial ports is displayed
+in the system log at /var/log/messages.
+
+If installed as a module, the module must be loaded.  This can be done
+manually by entering "modprobe rocket".  To have the module loaded automatically
+upon system boot, edit a /etc/modprobe.d/*.conf file and add the line
+"alias char-major-46 rocket".
+
+In order to use the ports, their device names (nodes) must be created with mknod.
+This is only required once, the system will retain the names once created.  To 
+create the RocketPort/RocketModem device names, use the command 
+"mknod /dev/ttyRx c 46 x" where x is the port number starting at zero.  For example:
+
+>mknod /dev/ttyR0 c 46 0
+>mknod /dev/ttyR1 c 46 1
+>mknod /dev/ttyR2 c 46 2  
+
+The Linux script MAKEDEV will create the first 16 ttyRx device names (nodes)
+for you:
+
+>/dev/MAKEDEV ttyR
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+ISA Rocketport Boards
+---------------------
+
+You must assign and configure the I/O addresses used by the ISA Rocketport
+card before installing and using it.  This is done by setting a set of DIP
+switches on the Rocketport board.
+
+
+SETTING THE I/O ADDRESS
+-----------------------
+
+Before installing RocketPort(R) or RocketPort RA boards, you must find
+a range of I/O addresses for it to use. The first RocketPort card
+requires a 68-byte contiguous block of I/O addresses, starting at one
+of the following: 0x100h, 0x140h, 0x180h, 0x200h, 0x240h, 0x280h,
+0x300h, 0x340h, 0x380h.  This I/O address must be reflected in the DIP
+switches of *all* of the Rocketport cards.
+
+The second, third, and fourth RocketPort cards require a 64-byte
+contiguous block of I/O addresses, starting at one of the following
+I/O addresses: 0x100h, 0x140h, 0x180h, 0x1C0h, 0x200h, 0x240h, 0x280h,
+0x2C0h, 0x300h, 0x340h, 0x380h, 0x3C0h.  The I/O address used by the
+second, third, and fourth Rocketport cards (if present) are set via
+software control.  The DIP switch settings for the I/O address must be
+set to the value of the first Rocketport cards.
+
+In order to distinguish each of the card from the others, each card
+must have a unique board ID set on the dip switches.  The first
+Rocketport board must be set with the DIP switches corresponding to
+the first board, the second board must be set with the DIP switches
+corresponding to the second board, etc.  IMPORTANT: The board ID is
+the only place where the DIP switch settings should differ between the
+various Rocketport boards in a system.
+
+The I/O address range used by any of the RocketPort cards must not
+conflict with any other cards in the system, including other
+RocketPort cards.  Below, you will find a list of commonly used I/O
+address ranges which may be in use by other devices in your system.
+On a Linux system, "cat /proc/ioports" will also be helpful in
+identifying what I/O addresses are being used by devices on your
+system.
+
+Remember, the FIRST RocketPort uses 68 I/O addresses.  So, if you set it
+for 0x100, it will occupy 0x100 to 0x143.  This would mean that you
+CAN NOT set the second, third or fourth board for address 0x140 since
+the first 4 bytes of that range are used by the first board.  You would
+need to set the second, third, or fourth board to one of the next available
+blocks such as 0x180.
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+RocketPort and RocketPort RA SW1 Settings:
+
+          +-------------------------------+
+          | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 |
+          +-------+-------+---------------+
+          | Unused| Card  | I/O Port Block|
+          +-------------------------------+
+
+DIP Switches                             DIP Switches
+7    8                                   6    5
+===================                      ===================
+On   On   UNUSED, MUST BE ON.            On   On   First Card    <==== Default
+                                         On   Off  Second Card
+                                         Off  On   Third Card
+                                         Off  Off  Fourth Card
+
+DIP Switches         I/O Address Range
+4    3    2    1     Used by the First Card
+=====================================
+On   Off  On   Off   100-143
+On   Off  Off  On    140-183
+On   Off  Off  Off   180-1C3       <==== Default
+Off  On   On   Off   200-243
+Off  On   Off  On    240-283
+Off  On   Off  Off   280-2C3
+Off  Off  On   Off   300-343
+Off  Off  Off  On    340-383
+Off  Off  Off  Off   380-3C3
+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+REPORTING BUGS
+--------------
+
+For technical support, please provide the following
+information: Driver version, kernel release, distribution of
+kernel, and type of board you are using. Error messages and log
+printouts port configuration details are especially helpful.
+
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+    Phone: (612) 494-4100
+      FAX: (612) 494-4199
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+
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+
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+
+=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
+
+
diff --git a/kernel/Documentation/serial/serial-rs485.txt b/kernel/Documentation/serial/serial-rs485.txt
new file mode 100644
index 000000000..39dac9542
--- /dev/null
+++ b/kernel/Documentation/serial/serial-rs485.txt
@@ -0,0 +1,136 @@
+                        RS485 SERIAL COMMUNICATIONS
+
+1. INTRODUCTION
+
+   EIA-485, also known as TIA/EIA-485 or RS-485, is a standard defining the
+   electrical characteristics of drivers and receivers for use in balanced
+   digital multipoint systems.
+   This standard is widely used for communications in industrial automation
+   because it can be used effectively over long distances and in electrically
+   noisy environments.
+
+2. HARDWARE-RELATED CONSIDERATIONS
+
+   Some CPUs/UARTs (e.g., Atmel AT91 or 16C950 UART) contain a built-in
+   half-duplex mode capable of automatically controlling line direction by
+   toggling RTS or DTR signals. That can be used to control external
+   half-duplex hardware like an RS485 transceiver or any RS232-connected
+   half-duplex devices like some modems.
+
+   For these microcontrollers, the Linux driver should be made capable of
+   working in both modes, and proper ioctls (see later) should be made
+   available at user-level to allow switching from one mode to the other, and
+   vice versa.
+
+3. DATA STRUCTURES ALREADY AVAILABLE IN THE KERNEL
+
+   The Linux kernel provides the serial_rs485 structure (see [1]) to handle
+   RS485 communications. This data structure is used to set and configure RS485
+   parameters in the platform data and in ioctls.
+
+   The device tree can also provide RS485 boot time parameters (see [2]
+   for bindings). The driver is in charge of filling this data structure from
+   the values given by the device tree.
+
+   Any driver for devices capable of working both as RS232 and RS485 should
+   provide at least the following ioctls:
+
+    - TIOCSRS485 (typically associated with number 0x542F). This ioctl is used
+      to enable/disable RS485 mode from user-space
+
+    - TIOCGRS485 (typically associated with number 0x542E). This ioctl is used
+      to get RS485 mode from kernel-space (i.e., driver) to user-space.
+
+   In other words, the serial driver should contain a code similar to the next
+   one:
+
+	static struct uart_ops atmel_pops = {
+		/* ... */
+		.ioctl		= handle_ioctl,
+	};
+
+	static int handle_ioctl(struct uart_port *port,
+		unsigned int cmd,
+		unsigned long arg)
+	{
+		struct serial_rs485 rs485conf;
+
+		switch (cmd) {
+		case TIOCSRS485:
+			if (copy_from_user(&rs485conf,
+				(struct serial_rs485 *) arg,
+				sizeof(rs485conf)))
+					return -EFAULT;
+
+			/* ... */
+			break;
+
+		case TIOCGRS485:
+			if (copy_to_user((struct serial_rs485 *) arg,
+				...,
+				sizeof(rs485conf)))
+					return -EFAULT;
+			/* ... */
+			break;
+
+		/* ... */
+		}
+	}
+
+
+4. USAGE FROM USER-LEVEL
+
+   From user-level, RS485 configuration can be get/set using the previous
+   ioctls. For instance, to set RS485 you can use the following code:
+
+	#include <linux/serial.h>
+
+	/* Driver-specific ioctls: */
+	#define TIOCGRS485      0x542E
+	#define TIOCSRS485      0x542F
+
+	/* Open your specific device (e.g., /dev/mydevice): */
+	int fd = open ("/dev/mydevice", O_RDWR);
+	if (fd < 0) {
+		/* Error handling. See errno. */
+	}
+
+	struct serial_rs485 rs485conf;
+
+	/* Enable RS485 mode: */
+	rs485conf.flags |= SER_RS485_ENABLED;
+
+	/* Set logical level for RTS pin equal to 1 when sending: */
+	rs485conf.flags |= SER_RS485_RTS_ON_SEND;
+	/* or, set logical level for RTS pin equal to 0 when sending: */
+	rs485conf.flags &= ~(SER_RS485_RTS_ON_SEND);
+
+	/* Set logical level for RTS pin equal to 1 after sending: */
+	rs485conf.flags |= SER_RS485_RTS_AFTER_SEND;
+	/* or, set logical level for RTS pin equal to 0 after sending: */
+	rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
+
+	/* Set rts delay before send, if needed: */
+	rs485conf.delay_rts_before_send = ...;
+
+	/* Set rts delay after send, if needed: */
+	rs485conf.delay_rts_after_send = ...;
+
+	/* Set this flag if you want to receive data even whilst sending data */
+	rs485conf.flags |= SER_RS485_RX_DURING_TX;
+
+	if (ioctl (fd, TIOCSRS485, &rs485conf) < 0) {
+		/* Error handling. See errno. */
+	}
+
+	/* Use read() and write() syscalls here... */
+
+	/* Close the device when finished: */
+	if (close (fd) < 0) {
+		/* Error handling. See errno. */
+	}
+
+5. REFERENCES
+
+ [1]	include/uapi/linux/serial.h
+ [2]	Documentation/devicetree/bindings/serial/rs485.txt
diff --git a/kernel/Documentation/serial/tty.txt b/kernel/Documentation/serial/tty.txt
new file mode 100644
index 000000000..dbe6623fe
--- /dev/null
+++ b/kernel/Documentation/serial/tty.txt
@@ -0,0 +1,304 @@
+
+			The Lockronomicon
+
+Your guide to the ancient and twisted locking policies of the tty layer and
+the warped logic behind them. Beware all ye who read on.
+
+FIXME: still need to work out the full set of BKL assumptions and document
+them so they can eventually be killed off.
+
+
+Line Discipline
+---------------
+
+Line disciplines are registered with tty_register_ldisc() passing the
+discipline number and the ldisc structure. At the point of registration the 
+discipline must be ready to use and it is possible it will get used before
+the call returns success. If the call returns an error then it won't get
+called. Do not re-use ldisc numbers as they are part of the userspace ABI
+and writing over an existing ldisc will cause demons to eat your computer.
+After the return the ldisc data has been copied so you may free your own 
+copy of the structure. You must not re-register over the top of the line
+discipline even with the same data or your computer again will be eaten by
+demons.
+
+In order to remove a line discipline call tty_unregister_ldisc().
+In ancient times this always worked. In modern times the function will
+return -EBUSY if the ldisc is currently in use. Since the ldisc referencing
+code manages the module counts this should not usually be a concern.
+
+Heed this warning: the reference count field of the registered copies of the
+tty_ldisc structure in the ldisc table counts the number of lines using this
+discipline. The reference count of the tty_ldisc structure within a tty 
+counts the number of active users of the ldisc at this instant. In effect it
+counts the number of threads of execution within an ldisc method (plus those
+about to enter and exit although this detail matters not).
+
+Line Discipline Methods
+-----------------------
+
+TTY side interfaces:
+
+open()		-	Called when the line discipline is attached to
+			the terminal. No other call into the line
+			discipline for this tty will occur until it
+			completes successfully. Returning an error will
+			prevent the ldisc from being attached. Can sleep.
+
+close()		-	This is called on a terminal when the line
+			discipline is being unplugged. At the point of
+			execution no further users will enter the
+			ldisc code for this tty. Can sleep.
+
+hangup()	-	Called when the tty line is hung up.
+			The line discipline should cease I/O to the tty.
+			No further calls into the ldisc code will occur.
+			The return value is ignored. Can sleep.
+
+write()		-	A process is writing data through the line
+			discipline.  Multiple write calls are serialized
+			by the tty layer for the ldisc.  May sleep. 
+
+flush_buffer()	-	(optional) May be called at any point between
+			open and close, and instructs the line discipline
+			to empty its input buffer.
+
+chars_in_buffer() -	(optional) Report the number of bytes in the input
+			buffer.
+
+set_termios()	-	(optional) Called on termios structure changes.
+			The caller passes the old termios data and the
+			current data is in the tty. Called under the
+			termios semaphore so allowed to sleep. Serialized
+			against itself only.
+
+read()		-	Move data from the line discipline to the user.
+			Multiple read calls may occur in parallel and the
+			ldisc must deal with serialization issues. May 
+			sleep.
+
+poll()		-	Check the status for the poll/select calls. Multiple
+			poll calls may occur in parallel. May sleep.
+
+ioctl()		-	Called when an ioctl is handed to the tty layer
+			that might be for the ldisc. Multiple ioctl calls
+			may occur in parallel. May sleep. 
+
+compat_ioctl()	-	Called when a 32 bit ioctl is handed to the tty layer
+			that might be for the ldisc. Multiple ioctl calls
+			may occur in parallel. May sleep.
+
+Driver Side Interfaces:
+
+receive_buf()	-	Hand buffers of bytes from the driver to the ldisc
+			for processing. Semantics currently rather
+			mysterious 8(
+
+write_wakeup()	-	May be called at any point between open and close.
+			The TTY_DO_WRITE_WAKEUP flag indicates if a call
+			is needed but always races versus calls. Thus the
+			ldisc must be careful about setting order and to
+			handle unexpected calls. Must not sleep.
+
+			The driver is forbidden from calling this directly
+			from the ->write call from the ldisc as the ldisc
+			is permitted to call the driver write method from
+			this function. In such a situation defer it.
+
+dcd_change()	-	Report to the tty line the current DCD pin status
+			changes and the relative timestamp. The timestamp
+			cannot be NULL.
+
+
+Driver Access
+
+Line discipline methods can call the following methods of the underlying
+hardware driver through the function pointers within the tty->driver
+structure:
+
+write()			Write a block of characters to the tty device.
+			Returns the number of characters accepted. The
+			character buffer passed to this method is already
+			in kernel space.
+
+put_char()		Queues a character for writing to the tty device.
+			If there is no room in the queue, the character is
+			ignored.
+
+flush_chars()		(Optional) If defined, must be called after
+			queueing characters with put_char() in order to
+			start transmission.
+
+write_room()		Returns the numbers of characters the tty driver
+			will accept for queueing to be written.
+
+ioctl()			Invoke device specific ioctl.
+			Expects data pointers to refer to userspace.
+			Returns ENOIOCTLCMD for unrecognized ioctl numbers.
+
+set_termios()		Notify the tty driver that the device's termios
+			settings have changed. New settings are in
+			tty->termios. Previous settings should be passed in
+			the "old" argument.
+
+			The API is defined such that the driver should return
+			the actual modes selected. This means that the
+			driver function is responsible for modifying any
+			bits in the request it cannot fulfill to indicate
+			the actual modes being used. A device with no
+			hardware capability for change (e.g. a USB dongle or
+			virtual port) can provide NULL for this method.
+
+throttle()		Notify the tty driver that input buffers for the
+			line discipline are close to full, and it should
+			somehow signal that no more characters should be
+			sent to the tty.
+
+unthrottle()		Notify the tty driver that characters can now be
+			sent to the tty without fear of overrunning the
+			input buffers of the line disciplines.
+
+stop()			Ask the tty driver to stop outputting characters
+			to the tty device.
+
+start()			Ask the tty driver to resume sending characters
+			to the tty device.
+
+hangup()		Ask the tty driver to hang up the tty device.
+
+break_ctl()		(Optional) Ask the tty driver to turn on or off
+			BREAK status on the RS-232 port.  If state is -1,
+			then the BREAK status should be turned on; if
+			state is 0, then BREAK should be turned off.
+			If this routine is not implemented, use ioctls
+			TIOCSBRK / TIOCCBRK instead.
+
+wait_until_sent()	Waits until the device has written out all of the
+			characters in its transmitter FIFO.
+
+send_xchar()		Send a high-priority XON/XOFF character to the device.
+
+
+Flags
+
+Line discipline methods have access to tty->flags field containing the
+following interesting flags:
+
+TTY_THROTTLED		Driver input is throttled. The ldisc should call
+			tty->driver->unthrottle() in order to resume
+			reception when it is ready to process more data.
+
+TTY_DO_WRITE_WAKEUP	If set, causes the driver to call the ldisc's
+			write_wakeup() method in order to resume
+			transmission when it can accept more data
+			to transmit.
+
+TTY_IO_ERROR		If set, causes all subsequent userspace read/write
+			calls on the tty to fail, returning -EIO.
+
+TTY_OTHER_CLOSED	Device is a pty and the other side has closed.
+
+TTY_OTHER_DONE		Device is a pty and the other side has closed and
+			all pending input processing has been completed.
+
+TTY_NO_WRITE_SPLIT	Prevent driver from splitting up writes into
+			smaller chunks.
+
+
+Locking
+
+Callers to the line discipline functions from the tty layer are required to
+take line discipline locks. The same is true of calls from the driver side
+but not yet enforced.
+
+Three calls are now provided
+
+	ldisc = tty_ldisc_ref(tty);
+
+takes a handle to the line discipline in the tty and returns it. If no ldisc
+is currently attached or the ldisc is being closed and re-opened at this
+point then NULL is returned. While this handle is held the ldisc will not
+change or go away.
+
+	tty_ldisc_deref(ldisc)
+
+Returns the ldisc reference and allows the ldisc to be closed. Returning the
+reference takes away your right to call the ldisc functions until you take
+a new reference.
+
+	ldisc = tty_ldisc_ref_wait(tty);
+
+Performs the same function as tty_ldisc_ref except that it will wait for an
+ldisc change to complete and then return a reference to the new ldisc. 
+
+While these functions are slightly slower than the old code they should have
+minimal impact as most receive logic uses the flip buffers and they only
+need to take a reference when they push bits up through the driver.
+
+A caution: The ldisc->open(), ldisc->close() and driver->set_ldisc 
+functions are called with the ldisc unavailable. Thus tty_ldisc_ref will
+fail in this situation if used within these functions. Ldisc and driver
+code calling its own functions must be careful in this case. 
+
+
+Driver Interface
+----------------
+
+open()		-	Called when a device is opened. May sleep
+
+close()		-	Called when a device is closed. At the point of
+			return from this call the driver must make no 
+			further ldisc calls of any kind. May sleep
+
+write()		-	Called to write bytes to the device. May not
+			sleep. May occur in parallel in special cases. 
+			Because this includes panic paths drivers generally
+			shouldn't try and do clever locking here.
+
+put_char()	-	Stuff a single character onto the queue. The
+			driver is guaranteed following up calls to
+			flush_chars.
+
+flush_chars()	-	Ask the kernel to write put_char queue
+
+write_room()	-	Return the number of characters that can be stuffed
+			into the port buffers without overflow (or less).
+			The ldisc is responsible for being intelligent
+ 			about multi-threading of write_room/write calls
+
+ioctl()		-	Called when an ioctl may be for the driver
+
+set_termios()	-	Called on termios change, serialized against
+			itself by a semaphore. May sleep.
+
+set_ldisc()	-	Notifier for discipline change. At the point this 
+			is done the discipline is not yet usable. Can now
+			sleep (I think)
+
+throttle()	-	Called by the ldisc to ask the driver to do flow
+			control.  Serialization including with unthrottle
+			is the job of the ldisc layer.
+
+unthrottle()	-	Called by the ldisc to ask the driver to stop flow
+			control.
+
+stop()		-	Ldisc notifier to the driver to stop output. As with
+			throttle the serializations with start() are down
+			to the ldisc layer.
+
+start()		-	Ldisc notifier to the driver to start output.
+
+hangup()	-	Ask the tty driver to cause a hangup initiated
+			from the host side. [Can sleep ??]
+
+break_ctl()	-	Send RS232 break. Can sleep. Can get called in
+			parallel, driver must serialize (for now), and
+			with write calls.
+
+wait_until_sent() -	Wait for characters to exit the hardware queue
+			of the driver. Can sleep
+
+send_xchar()	  -	Send XON/XOFF and if possible jump the queue with
+			it in order to get fast flow control responses.
+			Cannot sleep ??
+