This patch is based on the DMA-patch by Chip Coldwell for the AT91/AT32 serial
USARTS, with some tweaks to make it apply neatly on top of the other patches
in this series.

The RX and TX code has been moved to a tasklet and reworked a bit.  Instead of
depending on the ENDRX and TIMEOUT bits in CSR, we simply grab as much data as
we can from the DMA buffers.  I think this closes a race where the ENDRX bit
is set after we read CSR but before we read RPR, although I haven't confirmed
this.

Similarly, the two TX handlers (ENDTX and TXBUFE) have been combined into one.
 Since the current code only uses a single TX buffer, there's no point in
handling those interrupts separately.

This also fixes a DMA sync bug in the original patch.

[linux@bohmer.net: rebased onto irq-splitup patch]
[hskinnemoen@atmel.com: moved to tasklet, fixed dma bug, misc cleanups]
[hskinnemoen@atmel.com: atmel_serial dma: Misc fixes and cleanups]
Signed-off-by: NRemy Bohmer <linux@bohmer.net>
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Split up the interrupt handler of the serial port into a interrupt top-half
and a tasklet.

The goal is to get the interrupt top-half as short as possible to minimize
latencies on interrupts.  But the old code also does some calls in the
interrupt handler that are not allowed on preempt-RT in IRQF_NODELAY context.
This handler is executed in this context because of the interrupt sharing with
the timer interrupt.  The timer interrupt on Preempt-RT runs in IRQF_NODELAY
context.

The tasklet takes care of handling control status changes, pushing incoming
characters to the tty layer, handling break and other errors.  It also handles
pushing TX data into the data register.

Reading the complete receive queue is still done in the top-half because we
never want to miss any incoming character.

[hskinnemoen@atmel.com: misc cleanups and simplifications]
Signed-off-by: NRemy Bohmer <linux@bohmer.net>
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When an error happens in probe(), the clocks should be disabled, but
only if the port isn't already used as a console.

In remove(), the port struct shouldn't be freed because it's defined
statically.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If BRGR is zero, the baud rate generator isn't running, so the boot loader
can't have initialized the port.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace two instances of barrier() with cpu_relax() since that's the right
thing to do when busy-waiting.  This does not actually change anything since
cpu_relax() is defined as barrier() on both ARM and AVR32.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Clean up the atmel_serial driver to conform the coding rules.  It contains no
functional change.
Signed-off-by: NRemy Bohmer <linux@bohmer.net>
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <linux@maxim.org.za>
Tested-by: NMarc Pignat <marc.pignat@hevs.ch>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently early kernel messages, i.e., those from uncompression, go to the
debugging UART. And if it is enabled in the platform configuration, but
not initialized by the bootloader, the machine hangs, waiting for UART
status change. Besides, having those messages on another UART - typically
the console UART - may be preferrable. This patch allows selecting the
UART in kernel configuration.
Signed-off-by: NGuennadi Liakhovetski <lg@denx.de>
Acked-by: NAndrew Victor <linux@maxim.org.za>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Remove annoying build warnings about unused variables in atmel_serial,
which afflict both AT91 and AVR32 builds.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The RXBRK field in the AT91/AT32 USART status register has the
following definition according to e.g. the AT32AP7000 data sheet:

    RXBRK: Break Received/End of Break
    0: No Break received or End of Break detected since the last RSTSTA.
    1: Break Received or End of Break detected since the last RSTSTA.

Thus, for each break, the USART sets the RXBRK bit twice. This patch
modifies the driver to report the break event to the serial core only
once by keeping track of whether a break condition is currently
active. The break_active flag is reset as soon as a character is
received, so even if we miss the start-of-break interrupt this should
do the right thing.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Andrew Victor <andrew@sanpeople.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ivan Kuten <ivan.kuten@promwad.com>
Cc: Nicolas Ferre <nicolas.ferre@rfo.atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@rfo.atmel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Allow slower serial baud-rates by switching the UART clock from MCK to
MCK/8.

Based on patches by Mike Wolfram and Russell King.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Access to chip-internal registers should always be native-endian.  This is
especially important for AVR32 since it's a big-endian architecture and the
non-raw readl() and writel() macros are defined to do little-endian
accesses.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The Atmel AT91 and AVR32 processor architectures share many of the same
peripherals.  The PDC (Peripheral Data Controller) registers are also
implemented within in a number of the on-chip peripherals (eg, USART,
MMC, SPI, SSC, etc).

In a attempt not to duplicate the register definitions in each
peripheral, or in each architecture, the at91_pdc.h header in
asm-arm/arch-at91 and asm-avr32/arch-at32ap has been replaced with
linux/atmel_pdc.h.

The definitions have also been renamed from AT91_PDC_* to ATMEL_PDC_*,
and the drivers updated accordingly.

Original patch from Nicolas Ferre.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Acked-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch fixes the unbalanced calls to enable_irq_wake() and
disable_irq_wake() in the AT91 (and AVR32) serial driver.

It should resolve these kernel messages:
  Unbalanced IRQ x wake disable
  BUG: warning at kernel/irq/manage.c:167/set_irq_wake()

Original patch from Marc Pignat.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

A couple of whitespace cleanups, mainly in the AT91 header files.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This is the grungy swap all the occurrences in the right places patch that
goes with the updates.  At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs

If you are a tty driver author converting an out of tree driver the only
impact should be termios->ktermios name changes for the speed/property
setting functions from your upper layers.

If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)

Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia

[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix ->set_termios declaration]
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NMartin Peschke <mp3@de.ibm.com>
Acked-by: NPeter Oberparleiter <oberpar@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

1. The CPU identification has moved from <system.h> to <cpu.h>.

2. AT91RM9200_BASE_US0 is only defined if we are compiling in support
for the AT91RM9200.  Therefore we need to replace the CONFIG_ARM ifdef
with CONFIG_ARCH_AT91RM9200
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch updates the drivers (and other files) which include the
hardware headers.  This fixes the breakage introduced in patches 3950/1
and 3951/1 (those patches were getting big).

The AVR32 architecture uses the same serial driver and had its own copy
of at91rm9200_pdc.h.  Renamed it to at91_pdc.h
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch replaces the arch_identify() in system.h with a set of
cpu_is_XXX() macro's.  This allows for compile-time checking of the
target AT91 processor.

Original patch from David Brownell.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.
Signed-Off-By: NDavid Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

The atmel_console_get_options() function initializes the baud,
parity and bits settings from the actual hardware setup, in
case it has been initialized by a e.g. boot loader.

The baud rate, however, is not necessarily exactly equal to one of
the standard baud rates (115200, etc.) This means that the baud rate
calculated by this function may be slightly higher or slightly lower
than one of the standard baud rates.

If the baud rate is slightly lower than the target, this causes
problems when uart_set_option() tries to match the detected baud rate
against the standard baud rate, as it will always select a baud rate
that is lower or equal to the target rate. For example if the
detected baud rate is slightly lower than 115200, usart_set_options()
will select 57600.

This patch fixes the problem by subtracting 1 from the value in BRGR
when calculating the baud rate. The detected baud rate will thus
always be higher than the nearest standard baud rate, and
uart_set_options() will end up doing the right thing.

Tested on ATSTK1000 and AT91RM9200-EK boards. Both are broken without
this patch.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make CONFIG_SERIAL_ATMEL selectable on AVR32 and #ifdef out some ARM-
specific code in the driver.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In order to initialize the serial console early, the atmel_serial
driver had to do a hack where it compared the physical address of the
port with an address known to be permanently mapped, and used it as a
virtual address. This got around the limitation that ioremap() isn't
always available when the console is being initalized.

This patch removes that hack and replaces it with a new "regs" field
in struct atmel_uart_data that the board-specific code can initialize
to a fixed virtual mapping for platform devices where this is possible.
It also initializes the DBGU's regs field with the address the driver
used to check against.

On AVR32, the "regs" field is initialized from the physical base
address when this it can be accessed through a permanently 1:1 mapped
segment, i.e. the P4 segment.

If regs is NULL, the console initialization is delayed until the "real"
driver is up and running and ioremap() can be used.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename at91_register_uart_fns and associated structs and variables
to make it consistent with the atmel_ prefix used by the rest of
the driver.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The at91_serial driver can be used with both AT32 and AT91 devices
from Atmel and has therefore been renamed atmel_serial. The only
thing left is to rename PORT_AT91 PORT_ATMEL.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Prefix all internal functions and variables with atmel_ instead of
at91_.

The at91_register_uart_fns() stuff is left as is since I can't find
any actual users of it.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename the following public definitions:
  * AT91_NR_UART -> ATMEL_MAX_UART
  * struct at91_uart_data -> struct atmel_uart_data
  * at91_default_console_device -> atmel_default_console_device
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename the "at91_usart" platform driver "atmel_usart" and update
platform devices accordingly.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename the following Kconfig symbols:
  * CONFIG_SERIAL_AT91 -> CONFIG_SERIAL_ATMEL
  * CONFIG_SERIAL_AT91_CONSOLE -> CONFIG_SERIAL_ATMEL_CONSOLE
  * CONFIG_SERIAL_AT91_TTYAT -> CONFIG_SERIAL_ATMEL_TTYAT
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename at91_serial.c atmel_serial.c
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Move include/asm/arch/at91rm9200_usart.h into drivers/serial and rename
it atmel_usart.h. Also delete AVR32's version of this file.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is more preparation for adding support for the new Atmel AT91SAM9
processors.

Changes include:
- Replace AT91_BASE_* with AT91RM9200_BASE_*
- Replace AT91_ID_* with AT91RM9200_ID_*
- ROM, SRAM and UHP address definitions moved to at91rm9200.h.
- The raw AT91_P[ABCD]_* definitions are now depreciated in favour of
the GPIO API.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Andrew Victor

The AT91RM9200 errata work-around should be using the GPIO API and not
accessing the PIO registers directly.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

Also fixes all serial drivers.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Patch from Andrew Victor

This patch includes a number of updates to the AT91RM9200 serial driver.

Changes include:
1. Conversion to a platform_driver.  [Ivan Kokshaysky]
2. Replaced all references to AT91RM9200 with AT91.  This driver can now
also be used for the AT91SAM9216.
3. Allow TIOCM_LOOP to configure local loopback mode.
4. Cleaned up the 'read_status_mask' usage and interrupt handler code.
[Chip Coldwell]
5. Suspend/resume support.  [David Brownell]

There are a few 'unused variable' warning when compiling this - I
removed the new DMA support to keep this first patch simpler.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Glen Turner reported that writing LFCR rather than the more
traditional CRLF causes issues with some terminals.

Since this aflicts many serial drivers, extract the common code
to a library function (uart_console_write) and arrange for each
driver to supply a "putchar" function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Andrew Victor

This patch fixes two small issues with 2.6.15-git12.

1) Corrected major/minor numbers for ttyAT devices in the KConfig help.
   (Patch from Karl Olsen)

2) tty->flip.count has been removed.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Andrew Victor

This patch adds support to the 2.6 kernel series for the Atmel
AT91RM9200 processor.

This patch is the Serial driver.

This version uses the newly re-written GPL'ed hardware headers.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>