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>