Add offset & mask fields to struct powerdomain

In case of AM33xx family of devices, there is no consistency between
PWRSTCTRL & PWRSTST register offsers in PRM space, for example -

PRM_XXX           PWRSTCTRL     PWRSTST
=======================================
PRM_PER_MOD:      0x0C,         0x08
PRM_WKUP_MOD:     0x04,         0x08
PRM_MPU_MOD:      0x00,         0x04
PRM_DEVICE_MOD:   NA,           NA

And also, there is no consistency between bit-offsets inside
PWRSTCTRL & PWRSTST register, for example -

PRM_XXX           LOGICRET  MEMON  MEMRET
=======================================
GFX_PWRCTRL:      2,        17,    6
PER_PWRCTRL:      3,        25,    29
MPU_PWRCTRL:      2,        18,    22
WKUP_PWRCTRL:     3,        NA,    NA

This means, we need to maintain and pass on all this information
in powerdomain handle; so adding fields for,
   - PWRSTCTRL/ST register offset
   - Logic retention state mask
   - mem_on/ret/pwrst/retst mask

Currently, this fields is only applicable and used for AM33XX devices.
Signed-off-by: NVaibhav Hiremath <hvaibhav@ti.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: this patch is a combination of "Add offset & mask fields to
 struct powerdomain" and the powerdomain portions of "ARM: OMAP3+: am33xx:
 Add powerdomain & PRM support"; updated for 3.5]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

With patch 'ARM: OMAP2+: powerdomain: Wait for powerdomain transition
in pwrdm_state_switch()', the pwrdm_clkdm_state_switch() API becomes
duplicate of pwrdm_state_switch().

Get rid off duplicate pwrdm_clkdm_state_switch() and update the
users of it with pwrdm_state_switch()
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

get_context_loss_count functions return context loss count as u32, and
zero means an error. However, zero is also returned when context has
never been lost and could also be returned when the context loss count
has wrapped and goes to zero.

Change the functions to return an int, with negative value meaning an
error.

OMAP HSMMC code uses omap_pm_get_dev_context_loss_count(), but as the
hsmmc code handles the returned value as an int, with negative value
meaning an error, this patch actually fixes hsmmc code also.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NKevin Hilman <khilman@ti.com>
Acked-by: NPaul Walmsley <paul@pwsan.com>
[tony@atomide.com: updated to fix a warning with recent dmtimer changes]
Signed-off-by: NTony Lindgren <tony@atomide.com>

When a powerdomain is registered and it has an associated voltage domain,
add the powerdomain to the voltagedomain using voltdm_add_pwrdm().

Also add voltagedomain iterator helper functions to iterate over all
registered voltagedomains and all powerdomains associated with a
voltagedomain.

Modeled after a similar relationship between clockdomains and powerdomains.
Signed-off-by: NKevin Hilman <khilman@ti.com>

When a powerdomain is registered, lookup the voltage domain by name
and keep a pointer to the containing voltagedomain in the powerdomain
structure.

Modeled after similar method between powerdomain and clockdomain layers.
Signed-off-by: NKevin Hilman <khilman@ti.com>

Each powerdomain is associated with a voltage domain.  Add an entry to
struct powerdomain where the enclosing voltagedomain can be
referenced.

Modeled after similar relationship between clockdomains and powerdomains.
Signed-off-by: NKevin Hilman <khilman@ti.com>

At Tony's request, remove the omap_chip bitmasks from the powerdomain
definitions.  Instead, initialize powerdomains based on one or more
lists that are applicable to a particular SoC family, variant, and
silicon revision.

Gražvydas Ignotas <notasas@gmail.com> found and reported a bug in a
related patch that also applied to this patch - thanks Gražvydas.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Gražvydas Ignotas <notasas@gmail.com>

In preparation for OMAP_CHIP() removal, split pwrdm_init() into three
functions.  This allows some of them to be called multiple times: for
example, pwrdm_register_pwrdms() can be called once to register
powerdomains that are common to a group of SoCs, and once to register
powerdomains that are specific to a single SoC.

The appropriate order to call these functions - which is enforced
by the code - is:

1. pwrdm_register_platform_funcs()
2. pwrdm_register_pwrdms() (can be called multiple times)
3. pwrdm_complete_init()

Convert the OMAP2, 3, and 4 powerdomain init code to use these new
functions.

While here, improve documentation, and increase CodingStyle
conformance by shortening some local variable names.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

Some drivers wish to know whether the device that they control can
ever lose context, for example, when the device's enclosing
powerdomain loses power.  They can use this information to determine
whether it is necessary to save and restore device context, or whether
it can be skipped.  Implement the powerdomain portion of this by
adding the function pwrdm_can_ever_lose_context().  This is not for
use directly from driver code, but instead is intended to be called
from driver-subarch integration code (i.e., arch/arm/*omap* code).

Currently, the result from this function should be passed into the
driver code via struct platform_data, but at some point this should
be part of some common or OMAP-specific device code.

While here, update file copyrights.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

Trivial fix to remove the unused function declaration
from the powerdomain header.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

Add new powerdomain API

    u32 pwrdm_get_context_loss_count(struct powerdomain *pwrdm)

for checking how many times the powerdomain has lost context.  The
loss count is the sum of the powerdomain off-mode counter, the
logic off counter and the per-bank memory off counter.
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>
[paul@pwsan.com: removed bogus return value on error; improved kerneldoc;
 tweaked commit message]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

The OMAP powerdomain code and data is all OMAP2+-specific.  This seems
unlikely to change any time soon.  Move plat-omap/include/plat/powerdomain.h
to mach-omap2/powerdomain.h.  The primary point of doing this is to remove
the temptation for unrelated upper-layer code to access powerdomain code
and data directly.

As part of this process, remove the references to powerdomain data
from the GPIO "driver" and the OMAP PM no-op layer, both in plat-omap.
Change the DSPBridge code to point to the new location for the
powerdomain headers.  The DSPBridge code should not be including the
powerdomain headers; these should be removed.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Omar Ramirez Luna <omar.ramirez@ti.com>
Cc: Felipe Contreras <felipe.contreras@gmail.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>

OMAP4 powerdomain control registers are split between the PRM hardware
module and the PRCM_MPU local PRCM.  Add this PRCM partition
information to each OMAP4 powerdomain record, and convert the OMAP4
powerdomain function implementations to use the OMAP4 PRM instance
functions.

Also fixes a potential null pointer dereference of pwrdm->name.

The autogeneration scripts have been updated.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NRajendra Nayak <rnayak@ti.com>

Static data should be declared in .c files, not .h files.  It should be
possible to #include .h files at any point without creating multiple
copies of the same data.

We converted the clock data to .c files some time ago.  This patch does
the same for the powerdomain data.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NRajendra Nayak <rnayak@ti.com>

Put infrastructure in place, so arch specific func pointers
can be hooked up to the platform-independent part of the
framework.
This is in preparation of splitting the powerdomain framework into
platform-independent part (for all omaps) and platform-specific
parts.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Reviewed-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NRajendra Nayak <rnayak@ti.com>

powerdomains.h header today has only static definitions.  Adding any
function declarations into it and including it in multiple source file
is expected to cause issues.  Hence move all the static definitions
from powerdomains.h file into powerdomains_data.c file.

Also, create a new powerdomain section of the mach-omap2/Makefile, and
rearrange the prcm-common part of the Makefile, now that the
powerdomain code is in its own Makefile section.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: rearrange Makefile changes, tweaked commit message]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Reviewed-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NKevin Hilman <khilman@deeprootsystems.com>
Tested-by: NSantosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: NRajendra Nayak <rnayak@ti.com>

This patch fixes sparse warnings due non declarations of static functions.

arch/arm/mach-omap2/timer-gp.c:115:12: warning: symbol 'omap2_gp_clockevent_set_gptimer' was not declared. Should it be static?
arch/arm/mach-omap2/powerdomain.c:993:5: warning: symbol 'pwrdm_set_lowpwrstchange' was not declared. Should it be static?
arch/arm/mach-omap2/board-flash.c:141:8: warning: symbol 'board_nand_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-n8x0.c:416:6: warning: symbol 'n8x0_mmc_slot1_cover_handler' was not declared. Should it be static?
arch/arm/mach-omap2/board-n8x0.c:544:13: warning: symbol 'n8x0_mmc_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-rx51-peripherals.c:902:13: warning: symbol 'rx51_peripherals_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-rx51-video.c:107:13: warning: symbol 'rx51_video_mem_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-zoom-debugboard.c:155:12: warning: symbol 'zoom_debugboard_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-zoom-peripherals.c:280:13: warning: symbol 'zoom_peripherals_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-igep0020.c:110:13: warning: symbol 'igep2_flash_init' was not declared. Should it be static?
arch/arm/mach-omap2/board-am3517evm.c:109:6: warning: symbol 'am3517_evm_ethernet_init' was not declared. Should it be static?
drivers/mtd/onenand/omap2.c:577:5: warning: symbol 'omap2_onenand_rephase' was not declared. Should it be static?
Signed-off-by: NManjunath Kondaiah G <manjugk@ti.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>

DSS on ES2 supports only OSWR, hence remove the support
for CSWR from the powerdomain framework.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NBenoît Cousson <b-cousson@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

Some powerdomains in OMAP4 support a direct transition from one sleep
state to another deeper sleep state without having to wakeup the
powerdomain. This patch adds an api in the powerdomain framework to
set the LOWPOWERSTATECHANGE bit in PWRSTCTRL register.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

The pwrsts flag for ALWAYS ON domains like always_on_core_pwrdm
and wkup_pwrdm is wrongly populated with the define for a
powerdomain power state, instead of the allowable state
bitfields.
This causes a few api's to fail sensing invalid pwrst
requested.
Signed-off-by: NRajendra Nayak <rnayak@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

This patch adds counters to keep track of whether the powerdomain
logic or software controllable memory banks are turned off when
the power domain enters retention. During power domain retention
if logic gets turned off, the scenario is known as Open Switch Retention.
Also during retention s/w controllable memory banks of a power
domain can be chosen to be kept in retention or off.

This patch adds one counter per powerdomain to track the power domain
logic state during retention. Number of memory bank state counters
added depends on the number of software controllable memory banks
of the powerdomain. To view these counters do
	cat ../debug/pm_debug/count
Signed-off-by: NThara Gopinath <thara@ti.com>
[paul@pwsan.com: conditional expressions simplified; counter increment
 code moved to its own function]
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

This patch adds APIs pwrdm_read_logic_retst and
pwrdm_read_mem_retst for reading the next programmed
logic and memory state a powerdomain is to hit in event
of the next power domain state being retention.
These are needed for OSWR support.
Signed-off-by: NThara Gopinath <thara@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

This patch only affects documentation; no functional changes are
included.

Clean up comments in the current clockdomain, powerdomain code and
header files.  This mostly involves conversion to kerneldoc format,
although some clarifications are also included.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

This patch rearranges the order of structure members in struct powerdomain
to avoid wasting memory due to alignment restrictions.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

OMAP clockdomains and powerdomains are currently defined statically,
only registered at boot, and never unregistered, so we can remove the
unregister function and the locking.   A variant of this was originally
suggested a while ago by Dmitry Baryshkov <dbaryshkov@gmail.com>.
This version of this patch contains an additional fix from Kevin Hilman
<khilman@deeprootsystems.com> to address one of the pwrdm_for_each_nolock()
users in mach-omap2/pm-debug.c.   Thanks Kevin.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Dmitry Baryshkov <dbaryshkov@gmail.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

Move clockdomain wakeup dependency and sleep dependency data
structures from the powerdomain layer to the clockdomain layer, where
they belong.  These dependencies were originally placed in the
powerdomain layer due to unclear documentation; however, it is clear
now that these dependencies are between clockdomains.  For OMAP2/3,
this is not such a big problem, but for OMAP4 this needs to be fixed.

Thanks to Benoît Cousson <b-cousson@ti.com> for his advice on this
patch.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>

Taking care of the platform specific and common power domains with
proper checks.  Also refining some Macros according to the latest
OMAP4 requirements.
Signed-off-by: NAbhijit Pagare <abhijitpagare@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Benoit Cousson <b-cousson@ti.com>
Cc: Rajendra Nayak <rnayak@ti.com>

The Autogenerated OMAP4 power domain specific file (mach-omap2/powerdomains44xx.h)
is added here.
This file is auto-generated using python scripting and following is the list of the people
involved:
Paul Walmsley
Benoit Cousson
Abhijit Pagare
Signed-off-by: NAbhijit Pagare <abhijitpagare@ti.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NBenoit Cousson <b-cousson@ti.com>
Signed-off-by: NRajendra Nayak <rnayak@ti.com>

MPU power domain bank 0 bits are displayed in position of bank 1
in PWRSTS and PREPWRSTS registers. So read them from correct
position
Signed-off-by: NThara Gopinath <thara@ti.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

This patch rearranges the order of structure members in struct powerdomain
to avoid wasting memory due to alignment restrictions.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>

Replace some bare constants with power states.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>

Move the remaining headers under plat-omap/include/mach
to plat-omap/include/plat. Also search and replace the
files using these headers to include using the right path.

This was done with:

#!/bin/bash
mach_dir_old="arch/arm/plat-omap/include/mach"
plat_dir_new="arch/arm/plat-omap/include/plat"
headers=$(cd $mach_dir_old && ls *.h)
omap_dirs="arch/arm/*omap*/ \
drivers/video/omap \
sound/soc/omap"
other_files="drivers/leds/leds-ams-delta.c \
drivers/mfd/menelaus.c \
drivers/mfd/twl4030-core.c \
drivers/mtd/nand/ams-delta.c"

for header in $headers; do
	old="#include <mach\/$header"
	new="#include <plat\/$header"
	for dir in $omap_dirs; do
		find $dir -type f -name \*.[chS] | \
			xargs sed -i "s/$old/$new/"
	done
	find drivers/ -type f -name \*omap*.[chS] | \
		xargs sed -i "s/$old/$new/"
	for file in $other_files; do
		sed -i "s/$old/$new/" $file
	done
done

for header in $(ls $mach_dir_old/*.h); do
	git mv $header $plat_dir_new/
done
Signed-off-by: NTony Lindgren <tony@atomide.com>

The 'pwrdm_for_each()' function walks powerdomains with a spinlock
locked, so the the callbacks cannot do anything which may sleep.
This patch introduces a 'pwrdm_for_each_nolock()' helper which does
the same, but without the spinlock locked. This fixes the following
lockdep warning:

[    0.000000] WARNING: at kernel/lockdep.c:2460 lockdep_trace_alloc+0xac/0xec()
[    0.000000] Modules linked in:
(unwind_backtrace+0x0/0xdc) from [<c0045464>] (warn_slowpath_common+0x48/0x60)
(warn_slowpath_common+0x48/0x60) from [<c0067dd4>] (lockdep_trace_alloc+0xac/0xec)
(lockdep_trace_alloc+0xac/0xec) from [<c009da14>] (kmem_cache_alloc+0x1c/0xd0)
(kmem_cache_alloc+0x1c/0xd0) from [<c00b21d8>] (d_alloc+0x1c/0x1a4)
(d_alloc+0x1c/0x1a4) from [<c00a887c>] (__lookup_hash+0xd8/0x118)
(__lookup_hash+0xd8/0x118) from [<c00a9f20>] (lookup_one_len+0x84/0x94)
(lookup_one_len+0x84/0x94) from [<c010d12c>] (debugfs_create_file+0x8c/0x20c)
(debugfs_create_file+0x8c/0x20c) from [<c010d320>] (debugfs_create_dir+0x1c/0x20)
(debugfs_create_dir+0x1c/0x20) from [<c000e8cc>] (pwrdms_setup+0x60/0x90)
(pwrdms_setup+0x60/0x90) from [<c002e010>] (pwrdm_for_each+0x30/0x80)
(pwrdm_for_each+0x30/0x80) from [<c000e79c>] (pm_dbg_init+0x7c/0x14c)
(pm_dbg_init+0x7c/0x14c) from [<c00232b4>] (do_one_initcall+0x5c/0x1b8)
(do_one_initcall+0x5c/0x1b8) from [<c00083f8>] (kernel_init+0x90/0x10c)
(kernel_init+0x90/0x10c) from [<c00242c4>] (kernel_thread_exit+0x0/0x8)
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>

This patch provides the debugfs entries and a function which will be
called by the PM code to register the time spent per domain per
state. Also some new fields are added to the powerdomain struct to
keep the time information.

NOTE: As of v2.6.29, using getnstimeofday() after drivers are
suspended is no longer safe since the timekeeping subsystem is also
suspended as part of the suspend process.  Instead use sched_clock()
which on OMAP returns the 32k SYNC timer in nanoseconds.

Also, do not print out status for meta powerdomains (dpll*)
Signed-off-by: NPeter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: NTero Kristo <tero.kristo@nokia.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>

Add some infrastructure to easily iterate over clock and power
domains.
Signed-off-by: NPeter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>

This patch provides the infrastructure to count how many times a
powerdomain entered a given power state (on, inactive, retention,
off). A number of functions are provided which will be called by the
chip specific powerdomain and clockdomain code whenever a transition
might have happened.
Signed-off-by: NPeter 'p2' De Schrijver <peter.de-schrijver@nokia.com>
Signed-off-by: NKevin Hilman <khilman@deeprootsystems.com>

Add clockdomains for the CM and PRM.  These will ultimately replace the
"wkup_clkdm", which appears to not actually exist on the hardware.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix sparse & checkpatch warnings in OMAP2/3 PRCM & PM code.  This mostly
consists of:

- converting pointer comparisons to integers in form similar to
  (ptr == 0) to the standard idiom (!ptr)

- labeling a few non-static private functions as static

- adding prototypes for *_init() functions in the appropriate header
  files, and getting rid of the corresponding open-coded extern
  prototypes in other C files

- renaming the variable 'sclk' in mach-omap2/clock.c:omap2_get_apll_clkin
  to avoid shadowing an earlier declaration

Clean up checkpatch issues.  This mostly involves:

- converting some asm/ includes to linux/ includes

- cleaning up some whitespace

- getting rid of braces for conditionals with single following statements

Also take care of a few odds and ends, including:

- getting rid of unlikely() and likely() - none of this code is particularly
  fast-path code, so the performance impact seems slim; and some of those
  likely() and unlikely() indicators are probably not as accurate as the
  ARM's branch predictor

- removing some superfluous casts

linux-omap source commit is 347df59f5d20fdf905afbc26b1328b0e28a8a01b.
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

OMAP3430ES2+ introduces a new feature: optional powerdomain context
hardware save-and-restore (SAR).  Currently, this feature only applies
to USBHOST and USBTLL module context when the USBHOST or CORE
powerdomains enter a low-power sleep state[1].  This feature avoids
re-enumeration of USB devices when the powerdomains return from idle,
which is potentially time-consuming.

This patch adds support for enabling and disabling hardware
save-and-restore to the powerdomain code.  Three new functions are
added, pwrdm_enable_hdwr_sar(), pwrdm_disable_hdwr_sar(), and
pwrdm_can_hdwr_sar().  A new struct powerdomain "flags" field is
added, with a PWRDM_HAS_HDWR_SAR flag to indicate powerdomains with
SAR support.

Thanks to Jouni Högander <jouni.hogander@nokia.com> for reviewing an
earlier version of these patches, and Richard Woodruff <r-woodruff2@ti.com>
for clarifying the purpose of these bits.

1.  For the USBHOST controller module, context loss occurs when the
    USBHOST powerdomain enters off-idle.  For USBTLL, context loss
    occurs either if CORE enters off-idle, or if the CORE logic is
    configured to turn off when CORE enters retention-idle (OSWR).
    34xx ES2 TRM 4.8.6.1.1, 4.8.6.1.2
Signed-off-by: NPaul Walmsley <paul@pwsan.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>