ARM: Remove mach-msm and associated ARM architecture code

	- Intel IXP4xx Network processor.

Makefile

	- Build sourcefiles as part of the Documentation-build for arm

msm/

	- MSM specific documentation

Netwinder

	- Netwinder specific documentation

Porting

This document provides an overview of the msm_gpiomux interface, which

is used to provide gpio pin multiplexing and configuration on mach-msm

targets.

History

=======

The first-generation API for gpio configuration & multiplexing on msm

is the function gpio_tlmm_config().  This function has a few notable

shortcomings, which led to its deprecation and replacement by gpiomux:

The 'disable' parameter:  Setting the second parameter to

gpio_tlmm_config to GPIO_CFG_DISABLE tells the peripheral

processor in charge of the subsystem to perform a look-up into a

low-power table and apply the low-power/sleep setting for the pin.

As the msm family evolved this became problematic. Not all pins

have sleep settings, not all peripheral processors will accept requests

to apply said sleep settings, and not all msm targets have their gpio

subsystems managed by a peripheral processor. In order to get consistent

behavior on all targets, drivers are forced to ignore this parameter,

rendering it useless.

The 'direction' flag: for all mux-settings other than raw-gpio (0),

the output-enable bit of a gpio is hard-wired to a known

input (usually VDD or ground).  For those settings, the direction flag

is meaningless at best, and deceptive at worst.  In addition, using the

direction flag to change output-enable (OE) directly can cause trouble in

gpiolib, which has no visibility into gpio direction changes made

in this way.  Direction control in gpio mode should be made through gpiolib.

Key Features of gpiomux

=======================

- A consistent interface across all generations of msm.  Drivers can expect

the same results on every target.

- gpiomux plays nicely with gpiolib.  Functions that should belong to gpiolib

are left to gpiolib and not duplicated here.  gpiomux is written with the

intent that gpio_chips will call gpiomux reference-counting methods

from their request() and free() hooks, providing full integration.

- Tabular configuration.  Instead of having to call gpio_tlmm_config

hundreds of times, gpio configuration is placed in a single table.

- Per-gpio sleep.  Each gpio is individually reference counted, allowing only

those lines which are in use to be put in high-power states.

- 0 means 'do nothing': all flags are designed so that the default memset-zero

equates to a sensible default of 'no configuration', preventing users

from having to provide hundreds of 'no-op' configs for unused or

unwanted lines.

Usage

=====

To use gpiomux, provide configuration information for relevant gpio lines

in the msm_gpiomux_configs table.  Since a 0 equates to "unconfigured",

only those lines to be managed by gpiomux need to be specified.  Here

is a completely fictional example:

struct msm_gpiomux_config msm_gpiomux_configs[GPIOMUX_NGPIOS] = {

	[12] = {

		.active = GPIOMUX_VALID | GPIOMUX_DRV_8MA | GPIOMUX_FUNC_1,

		.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,

	},

	[34] = {

		.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,

	},

};

To indicate that a gpio is in use, call msm_gpiomux_get() to increase

its reference count.  To decrease the reference count, call msm_gpiomux_put().

The effect of this configuration is as follows:

When the system boots, gpios 12 and 34 will be initialized with their

'suspended' configurations.  All other gpios, which were left unconfigured,

will not be touched.

When msm_gpiomux_get() is called on gpio 12 to raise its reference count

above 0, its active configuration will be applied.  Since no other gpio

line has a valid active configuration, msm_gpiomux_get() will have no

effect on any other line.

When msm_gpiomux_put() is called on gpio 12 or 34 to drop their reference

count to 0, their suspended configurations will be applied.

Since no other gpio line has a valid suspended configuration, no other

gpio line will be effected by msm_gpiomux_put().  Since gpio 34 has no valid

active configuration, this is effectively a no-op for gpio 34 as well,

with one small caveat, see the section "About Output-Enable Settings".

All of the GPIOMUX_VALID flags may seem like unnecessary overhead, but

they address some important issues.  As unused entries (all those

except 12 and 34) are zero-filled, gpiomux needs a way to distinguish

the used fields from the unused.  In addition, the all-zero pattern

is a valid configuration!  Therefore, gpiomux defines an additional bit

which is used to indicate when a field is used.  This has the pleasant

side-effect of allowing calls to msm_gpiomux_write to use '0' to indicate

that a value should not be changed:

  msm_gpiomux_write(0, GPIOMUX_VALID, 0);

replaces the active configuration of gpio 0 with an all-zero configuration,

but leaves the suspended configuration as it was.

Static Configurations

=====================

To install a static configuration, which is applied at boot and does

not change after that, install a configuration with a suspended component

but no active component, as in the previous example:

	[34] = {

		.suspended = GPIOMUX_VALID | GPIOMUX_PULL_DOWN,

	},

The suspended setting is applied during boot, and the lack of any valid

active setting prevents any other setting from being applied at runtime.

If other subsystems attempting to access the line is a concern, one could

*really* anchor the configuration down by calling msm_gpiomux_get on the

line at initialization to move the line into active mode.  With the line

held, it will never be re-suspended, and with no valid active configuration,

no new configurations will be applied.

But then, if having other subsystems grabbing for the line is truly a concern,

it should be reserved with gpio_request instead, which carries an implicit

msm_gpiomux_get.

gpiomux and gpiolib

===================

It is expected that msm gpio_chips will call msm_gpiomux_get() and

msm_gpiomux_put() from their request and free hooks, like this fictional

example:

static int request(struct gpio_chip *chip, unsigned offset)

{

        return msm_gpiomux_get(chip->base + offset);

}

static void free(struct gpio_chip *chip, unsigned offset)

{

        msm_gpiomux_put(chip->base + offset);

}

	...somewhere in a gpio_chip declaration...

	.request = request,

	.free    = free,

This provides important functionality:

- It guarantees that a gpio line will have its 'active' config applied

  when the line is requested, and will not be suspended while the line

  remains requested; and

- It guarantees that gpio-direction settings from gpiolib behave sensibly.

  See "About Output-Enable Settings."

This mechanism allows for "auto-request" of gpiomux lines via gpiolib

when it is suitable.  Drivers wishing more exact control are, of course,

free to also use msm_gpiomux_set and msm_gpiomux_get.

About Output-Enable Settings

============================

Some msm targets do not have the ability to query the current gpio

configuration setting.  This means that changes made to the output-enable

(OE) bit by gpiolib cannot be consistently detected and preserved by gpiomux.

Therefore, when gpiomux applies a configuration setting, any direction

settings which may have been applied by gpiolib are lost and the default

input settings are re-applied.

For this reason, drivers should not assume that gpio direction settings

continue to hold if they free and then re-request a gpio.  This seems like

common sense - after all, anybody could have obtained the line in the

meantime - but it needs saying.

This also means that calls to msm_gpiomux_write will reset the OE bit,

which means that if the gpio line is held by a client of gpiolib and

msm_gpiomux_write is called, the direction setting has been lost and

gpiolib's internal state has been broken.

Release gpio lines before reconfiguring them.

W:	http://wiki.openmoko.org/wiki/Neo_FreeRunner

S:	Supported

ARM/QUALCOMM MSM MACHINE SUPPORT

M:	David Brown <davidb@codeaurora.org>

M:	Daniel Walker <dwalker@fifo99.com>

M:	Bryan Huntsman <bryanh@codeaurora.org>

L:	linux-arm-msm@vger.kernel.org

F:	arch/arm/mach-msm/

F:	drivers/video/fbdev/msm/

F:	drivers/mmc/host/msm_sdcc.c

F:	drivers/mmc/host/msm_sdcc.h

F:	drivers/tty/serial/msm_serial.h

F:	drivers/tty/serial/msm_serial.c

F:	drivers/*/pm8???-*

F:	drivers/mfd/ssbi.c

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/davidb/linux-msm.git

S:	Maintained

ARM/TOSA MACHINE SUPPORT

M:	Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>

M:	Dirk Opfer <dirk@opfer-online.de>

S:	Maintained

F:	arch/arm/mach-qcom/

F:	drivers/soc/qcom/

F:	drivers/tty/serial/msm_serial.h

F:	drivers/tty/serial/msm_serial.c

F:	drivers/*/pm8???-*

F:	drivers/mfd/ssbi.c

T:	git git://git.kernel.org/pub/scm/linux/kernel/git/galak/linux-qcom.git

ARM/RADISYS ENP2611 MACHINE SUPPORT

	help

	  Support for Intel/Marvell's PXA2xx/PXA3xx processor line.

config ARCH_MSM

	bool "Qualcomm MSM (non-multiplatform)"

	select ARCH_REQUIRE_GPIOLIB

	select COMMON_CLK

	select GENERIC_CLOCKEVENTS

	help

	  Support for Qualcomm MSM/QSD based systems.  This runs on the

	  apps processor of the MSM/QSD and depends on a shared memory

	  interface to the modem processor which runs the baseband

	  stack and controls some vital subsystems

	  (clock and power control, etc).

config ARCH_SHMOBILE_LEGACY

	bool "Renesas ARM SoCs (non-multiplatform)"

	select ARCH_SHMOBILE

source "arch/arm/mach-meson/Kconfig"

source "arch/arm/mach-msm/Kconfig"

source "arch/arm/mach-moxart/Kconfig"

source "arch/arm/mach-mv78xx0/Kconfig"

		  Say Y here if you want kernel low-level debugging support

		  on MMP UART3.

	config DEBUG_MSM_UART

		bool "Kernel low-level debugging messages via MSM UART"

		depends on ARCH_MSM

		help

		  Say Y here if you want the debug print routines to direct

		  their output to the serial port on MSM devices.

		  ARCH                DEBUG_UART_PHYS   DEBUG_UART_VIRT   #

		  MSM7X00A, QSD8X50   0xa9a00000        0xe1000000        UART1

		  MSM7X00A, QSD8X50   0xa9b00000        0xe1000000        UART2

		  MSM7X00A, QSD8X50   0xa9c00000        0xe1000000        UART3

		  MSM7X30             0xaca00000        0xe1000000        UART1

		  MSM7X30             0xacb00000        0xe1000000        UART2

		  MSM7X30             0xacc00000        0xe1000000        UART3

		  Please adjust DEBUG_UART_PHYS and DEBUG_UART_BASE configuration

		  options based on your needs.

	config DEBUG_QCOM_UARTDM

		bool "Kernel low-level debugging messages via QCOM UARTDM"

		depends on ARCH_QCOM

				 DEBUG_IMX6SL_UART || \

				 DEBUG_IMX6SX_UART

	default "debug/ks8695.S" if DEBUG_KS8695_UART

	default "debug/msm.S" if DEBUG_MSM_UART || DEBUG_QCOM_UARTDM

	default "debug/msm.S" if DEBUG_QCOM_UARTDM

	default "debug/netx.S" if DEBUG_NETX_UART

	default "debug/omap2plus.S" if DEBUG_OMAP2PLUS_UART

	default "debug/renesas-scif.S" if DEBUG_R7S72100_SCIF2

	default 0x80230000 if DEBUG_PICOXCELL_UART

	default 0x808c0000 if ARCH_EP93XX

	default 0x90020000 if DEBUG_NSPIRE_CLASSIC_UART || DEBUG_NSPIRE_CX_UART

	default 0xa9a00000 if DEBUG_MSM_UART

	default 0xb0060000 if DEBUG_SIRFPRIMA2_UART1

	default 0xb0090000 if DEBUG_VEXPRESS_UART0_CRX

	default 0xc0013000 if DEBUG_U300_UART

	        DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \

		DEBUG_LL_UART_EFM32 || \

		DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \

		DEBUG_MSM_UART || DEBUG_NETX_UART || \

		DEBUG_NETX_UART || \

		DEBUG_QCOM_UARTDM || DEBUG_R7S72100_SCIF2 || \

		DEBUG_RCAR_GEN1_SCIF0 || DEBUG_RCAR_GEN1_SCIF2 || \

		DEBUG_RCAR_GEN2_SCIF0 || DEBUG_RCAR_GEN2_SCIF2 || \

	hex "Virtual base address of debug UART"

	default 0xe0000a00 if DEBUG_NETX_UART

	default 0xe0010fe0 if ARCH_RPC

	default 0xe1000000 if DEBUG_MSM_UART

	default 0xf0000be0 if ARCH_EBSA110

	default 0xf0010000 if DEBUG_ASM9260_UART

	default 0xf01fb000 if DEBUG_NOMADIK_UART

	default DEBUG_UART_PHYS if !MMU

	depends on DEBUG_LL_UART_8250 || DEBUG_LL_UART_PL01X || \

		DEBUG_UART_8250 || DEBUG_UART_PL01X || DEBUG_MESON_UARTAO || \

		DEBUG_MSM_UART || DEBUG_NETX_UART || \

		DEBUG_NETX_UART || \

		DEBUG_QCOM_UARTDM || DEBUG_S3C24XX_UART || \

		DEBUG_UART_BCM63XX || DEBUG_ASM9260_UART || \

		DEBUG_SIRFSOC_UART || DEBUG_DIGICOLOR_UA0

config DEBUG_UNCOMPRESS

	bool

	depends on ARCH_MULTIPLATFORM || ARCH_MSM || PLAT_SAMSUNG

	depends on ARCH_MULTIPLATFORM || PLAT_SAMSUNG

	default y if DEBUG_LL && !DEBUG_OMAP2PLUS_UART && \

		     (!DEBUG_TEGRA_UART || !ZBOOT_ROM)

	help