Commit Graph

4982 Commits

Author SHA1 Message Date
Kevin Hilman
4af4016c53 OMAP3: PM: UART: disable clocks when idle and off-mode support
This patch allows the UART clocks to be disabled when the OMAP UARTs
are inactive, thus permitting the chip to hit retention in idle.
After the expiration of an activity timer, each UART is allowed to
disable its clocks so the system can enter retention.  The activity
timer is (re)activated on any UART interrupt, UART wake event or any
IO pad wakeup.  The actual disable of the UART clocks is done in the
'prepare_idle' hook called from the OMAP idle loop.

While the activity timer is active, the smart-idle mode of the UART is
also disabled.  This is due to a "feature" of the UART module that
after a UART wakeup, the smart-idle mode may be entered before the
UART has communicated the interrupt, or upon TX, an idle mode may be
entered before the TX FIFOs are emptied.

Upon suspend, the 'prepare_suspend' hook cancels any pending activity
timers and allows the clocks to be disabled immediately.

In addition, upon disabling clocks the UART state is saved in case
of an off-mode transition while clocks are off.

Special thanks to Tero Kristo for the initial ideas and first versions
of UART idle support, and to Jouni Hogander for extra testing and
bugfixes.

Tested on OMAP3 (Beagle, RX51, SDP, EVM) and OMAP2 (n810)

Cc: Tero Kristo <tero.kristo@nokia.com>
Cc: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-28 10:59:06 -07:00
Kevin Hilman
5a1a5abdb2 OMAP3: PM: Add wake-up bit defintiions for CONTROL_PADCONF_X
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-28 10:59:06 -07:00
Kevin Hilman
1155e426b7 OMAP3: PM: Force IVA2 into idle during bootup
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-28 10:59:05 -07:00
Jouni Hogander
94434535bd OMAP: Add new function to check wether there is irq pending
Add common omap2/3 function to check wether there is irq pending.
Switch to use it in omap2 pm code instead of its own.

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-28 10:59:04 -07:00
Kevin Hilman
8bd2294922 OMAP2/3: PM: push core PM code from linux-omap
This patch is to sync the core linux-omap PM code with mainline.  This
code has evolved and been used for a while the linux-omap tree, but
the attempt here is to finally get this into mainline.

Following this will be a series of patches from the 'PM branch' of the
linux-omap tree to add full PM hardware support from the linux-omap
tree.

Much of this PM core code was written by Jouni Hogander with
significant contributions from Paul Walmsley as well as many others
from Nokia, Texas Instruments and linux-omap community.

Signed-off-by: Jouni Hogander <jouni.hogander@nokia.com>
Cc: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-28 10:58:50 -07:00
Kevin Hilman
a330bd4750 Revert "ARM: OMAP: Mask interrupts when disabling interrupts, v2"
This reverts commit 5461af5af5.

Adding a disable hook to the irq_chip is not the way to fix the
problem being addressed by this patch.  Instead, we need to fix
support for [enable|disable]_irq_wake().

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
2009-05-26 15:56:55 -07:00
Tony Lindgren
88b6f7eb9b Merge branch 'omap-clock-upstream' of git://git.pwsan.com/linux-2.6 into for-next 2009-05-26 14:41:35 -07:00
Santosh Shilimkar
8f9ccfeeb2 ARM: OMAP: Remove unnecessary omap2_globals.
This patch removes unnecessary omap2_globals and pass the global structures
directly as function argument.

The proposed cleanup was suggested by Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:48 -07:00
Santosh Shilimkar
da7a0649bc ARM: OMAP: Remove useless omap_sram_error function.
This patch removes fixes omap_sram_error() function and replace the
error paths with BUG_ON.

The proposed fix was suggested by Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:48 -07:00
Santosh Shilimkar
ce8a17fd3f ARM: OMAP: Remove unwanted type casts and fix the compiler warning.
This patch fixes the compiler warning "assignment from incompatible
pointer type"  in dmtimer.c and removes the tye casts. These warnings
were suppressed by type catsing.

The proposed fix was suggested by Russell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:47 -07:00
Tony Lindgren
d76076636b ARM: OMAP2/3: Reorganize Makefile to add omap4 support
We don't necessarily want to compile in irq.o and sdrc.o for omap4.
Also, clock and prcm may not be implemented initially.

Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:47 -07:00
Tony Lindgren
ef6685a6de ARM: OMAP2/3: Remove OMAP_CM_REGADDR
Processor specific macros should be used instead.

Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:46 -07:00
Tony Lindgren
07b95d000d ARM: OMAP2/3: Remove OMAP2_PRCM_BASE
It's currently unused, and processor specific defines should
be used instead.

Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:46 -07:00
Tony Lindgren
2e693f841f ARM: OMAP2/3: Move define of OMAP2_VA_IC_BASE to be local to entry-macro.S
Move define of OMAP2_VA_IC_BASE to be local to entry-macro.S

Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:45 -07:00
Tony Lindgren
8e3bd351d1 ARM: OMAP2/3: Remove OMAP_PRM_REGADDR and OMAP2_PRM_BASE
Remove OMAP_PRM_REGADDR and use processor specific defines instead.

Also fold in a patch from Kevin Hilman to add _OFFSET #defines
for the PRCM registers to be used with the prm_[read|write]_* macros.
These are used extensively in the forthcoming OMAP PM support.

Also remove now unused OMAP2_PRM_BASE.

Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:42 -07:00
Tony Lindgren
a4ab0d836b ARM: OMAP2/3: Remove OMAP2_32KSYNCT_BASE
Use processor specific defines instead.

As an extra bonus, this patch fixes the problem of CONFIG_DEBUG_SPINLOCK
calling sched_clock before we have things initialized:

http://patchwork.kernel.org/patch/15810/

Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-25 11:26:41 -07:00
Rabin Vincent
a93ea9b357 [ARM] 5517/1: integrator: don't put clock lookups in __initdata
Remove the __initdata annotation for the clock lookups, since they
will be needed when loading modules which use clk_get().

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-18 17:43:16 +01:00
Rabin Vincent
982db66352 [ARM] 5518/1: versatile: don't put clock lookups in __initdata
Remove the __initdata annotation for the clock lookups, since they
will be needed when loading modules which use clk_get().

Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-18 17:43:06 +01:00
Pavel Roskin
8190b37f64 [ARM] mach-l7200: fix spelling of SYS_CLOCK_OFF
Signed-off-by: Pavel Roskin <proski@gnu.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-18 11:25:08 +01:00
Mel Gorman
eb33575cf6 [ARM] Double check memmap is actually valid with a memmap has unexpected holes V2
pfn_valid() is meant to be able to tell if a given PFN has valid memmap
associated with it or not. In FLATMEM, it is expected that holes always
have valid memmap as long as there is valid PFNs either side of the hole.
In SPARSEMEM, it is assumed that a valid section has a memmap for the
entire section.

However, ARM and maybe other embedded architectures in the future free
memmap backing holes to save memory on the assumption the memmap is never
used. The page_zone linkages are then broken even though pfn_valid()
returns true. A walker of the full memmap must then do this additional
check to ensure the memmap they are looking at is sane by making sure the
zone and PFN linkages are still valid. This is expensive, but walkers of
the full memmap are extremely rare.

This was caught before for FLATMEM and hacked around but it hits again for
SPARSEMEM because the page_zone linkages can look ok where the PFN linkages
are totally screwed. This looks like a hatchet job but the reality is that
any clean solution would end up consumning all the memory saved by punching
these unexpected holes in the memmap. For example, we tried marking the
memmap within the section invalid but the section size exceeds the size of
the hole in most cases so pfn_valid() starts returning false where valid
memmap exists. Shrinking the size of the section would increase memory
consumption offsetting the gains.

This patch identifies when an architecture is punching unexpected holes
in the memmap that the memory model cannot automatically detect and sets
ARCH_HAS_HOLES_MEMORYMODEL. At the moment, this is restricted to EP93xx
which is the model sub-architecture this has been reported on but may expand
later. When set, walkers of the full memmap must call memmap_valid_within()
for each PFN and passing in what it expects the page and zone to be for
that PFN. If it finds the linkages to be broken, it assumes the memmap is
invalid for that PFN.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-18 11:22:24 +01:00
Russell King
e1342f1da0 Merge branch 'smp-fix' 2009-05-17 17:13:18 +01:00
Russell King
ee348d5a1d [ARM] realview: fix broadcast tick support
Having discussed broadcast tick support with Thomas Glexiner, the
broadcast tick devices should be registered with a higher rating
than the global tick device, and it should have the ONESHOT and
PERIODIC feature flags set.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Thomas Glexiner <tglx@linutronix.de>
2009-05-17 17:11:35 +01:00
Russell King
78d236c2b3 [ARM] realview: remove useless smp_cross_call_done()
smp_cross_call_done() is a no-op for MPCore, and since it's only
used by platform code, there's no point in having it unless it's
doing something.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-17 16:23:45 +01:00
Russell King
826681043d [ARM] smp: fix cpumask usage in ARM SMP code
The ARM SMP code wasn't properly updated for the cpumask changes, which
results in smp_timer_broadcast() broadcasting ticks to non-online CPUs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-17 16:22:46 +01:00
Ricardo Martins
776abac817 [ARM] 5513/1: Eurotech VIPER SBC: fix compilation error
Compilation for this board yields the following errors:

arch/arm/mach-pxa/viper.c:511: error: 'FFUART' undeclared here (not in a function)
arch/arm/mach-pxa/viper.c:520: error: 'BTUART' undeclared here (not in a function)
arch/arm/mach-pxa/viper.c:529: error: 'STUART' undeclared here (not in a function)

Fix them by including the necessary header.

Signed-off-by: Ricardo Martins <rasm@fe.up.pt>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-16 19:55:56 +01:00
Hartley Sweeten
ff05c0330b [ARM] 5509/1: ep93xx: clkdev enable UARTS
Fix the clkdev API support for the ep93xx uart clocks.

The uarts available in the ep93xx have individual clock controls.
The current implementation assumes that the bootloader has enabled
the clocks before the kernel has booted. It also assumes that the
bootloader has set the UARTBAUD bit indicating that the uarts are
running off the 14.7456MHz external crystal.

This fixes both issues. It also allows the uart clocks to be stopped
when there are no users.

Tested-by: Matthias Kaehlcke <matthias@kaehlcke.net>

Cc: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-05-16 19:55:56 +01:00
Russell King
cddb783552 Merge branch 'omap-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6 2009-05-16 19:51:20 +01:00
Russell King
b477dfba38 Merge branch 'fixes-rc5' of git://aeryn.fluff.org.uk/bjdooks/linux 2009-05-16 17:54:19 +01:00
Tony Lindgren
005187eeca ARM: OMAP2/3: Change omapfb to use clkdev for dispc and rfbi, v2
This makes the framebuffer work on omap3.

Also fix the clk_get usage for checkpatch.pl
"ERROR: do not use assignment in if condition".

Cc: Imre Deak <imre.deak@nokia.com>
Cc: linux-fbdev-devel@lists.sourceforge.net
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-16 08:28:17 -07:00
Kalle Jokiniemi
8dbe43930a ARM: OMAP3: Fix HW SAVEANDRESTORE shift define
The OMAP3430ES2_SAVEANDRESTORE_SHIFT macro is used
by powerdomain code in
"1 << OMAP3430ES2_SAVEANDRESTORE_SHIFT" manner, but
the definition was also (1 << 4), meaning we actually
modified bit 16. So the definition needs to be 4.

This fixes also a cold reset HW bug in OMAP3430 ES3.x
where some of the efuse bits are not isolated during
wake-up from off mode. This can cause randomish
cold resets with off mode. Enabling the USBTLL hardware
SAVEANDRESTORE causes the core power up assert to be
delayed in a way that we will not get faulty values
when boot ROM is reading the unisolated registers.

Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Acked-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-16 08:28:17 -07:00
Vikram Pandita
e102657ed1 ARM: OMAP3: Fix number of GPIO lines for 34xx
As per 3430 TRM, there are 6 banks [0 to 191]

Signed-off-by: Tom Rix <Tom.Rix@windriver.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-05-16 08:28:16 -07:00
Linus Torvalds
c244450dac Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
  ASoC: DaVinci EVM board support buildfixes
  ASoC: DaVinci I2S updates
  ASoC: davinci-pcm buildfixes
  ALSA: pcsp: fix printk format warning
  ALSA: riptide: postfix increment and off by one
  pxa2xx-ac97: fix reset gpio mode setting
  ASoC: soc-core: fix crash when removing not instantiated card
2009-05-15 08:06:56 -07:00
Ben Dooks
3ac19bb443 [ARM] S3C: Do not set clk->owner field if unset
The s3c24xx_register_clock() function has been doing a test
on clk->owner to see if it is NULL, and then setting itself
as the owner if clk->owner == NULL.

This is not needed, arch/arm/plat-s3c/clock.c cannot be
compiled as a module, and even if it was, it should not be
playing with this field if it being registered from somewhere
else.

The best course of action is to remove this bit of
code completely.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:21:57 +01:00
Ben Dooks
a8af6de00f [ARM] S3C2410: mach-bast.c registering i2c data too early
The BAST support code is calling s3c_i2c0_set_platdata() from
the map_io() entry, instead of the bast_init() code. This causes
the registration to fail due to kmalloc() not being available
at the time.

This fixes the following error:
s3c_i2c0_set_platdata: no memory for platform data

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:13:25 +01:00
Ben Dooks
871fcd7cf7 [ARM] S3C24XX: Fix unused code warning in arch/arm/plat-s3c24xx/dma.c
Fix unused code warning in arch/arm/plat-s3c24xx/dma.c if there
is no PM support enabled. The function to_dma_chan() should
be marked inline so that the compiler will eliminate it without
warning if it isn't used.

arch/arm/plat-s3c24xx/dma.c:1239: warning: 'to_dma_chan' defined but not used

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:13:24 +01:00
Marek Szyprowski
beb9f4ed22 [ARM] S3C64XX: fix GPIO debug
Fix compilation bug when debug was enabled

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:13:18 +01:00
Marek Szyprowski
f36dd6e7c0 [ARM] S3C64XX: GPIO include cleanup
Cleanup arm/plat-s3c64xx/include/plat/gpio-bank-h.h include file.
Using shift-left operation with value >32 is a bad habit.

Reviewed-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 15:13:06 +01:00
Takashi Iwai
60befb97f5 Merge branch 'fix/asoc' into for-linus
* fix/asoc:
  ASoC: DaVinci EVM board support buildfixes
  ASoC: DaVinci I2S updates
  ASoC: davinci-pcm buildfixes
  pxa2xx-ac97: fix reset gpio mode setting
  ASoC: soc-core: fix crash when removing not instantiated card
2009-05-15 15:38:26 +02:00
Ben Dooks
3ea385f061 [ARM] nwfpe: fix 'floatx80_is_nan' sparse warning
The symbol 'floatx80_is_nan' prototype was defined
locally in fpa11_cprt.c when it was built outside the
file in softfloat-specialisze.

Move this into softfloat.h to fix the following sparse
warning:

softfloat-specialize:276:6: warning: symbol 'floatx80_is_nan' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 12:49:14 +01:00
Ben Dooks
ceec1c33c3 [ARM] nwfpe: Add decleration for ExtendedCPDO
Add header file decleration for 'ExtendedCPDO' in fpa11.h
to stop the following sparse warning:

extended_cpdo.c:90:14: warning: symbol 'ExtendedCPDO' was not declared. Should it be static?

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
2009-05-15 12:49:08 +01:00
David Brownell
f492ec9f02 ASoC: DaVinci EVM board support buildfixes
This is a build fix, resyncing the DaVinci EVM ASoC board code
with the version in the DaVinci tree.  That resync includes
support for the DM355 EVM, although that board isn't yet in
mainline.

(NOTE:  also includes a bugfix to the platform_add_resources
call, recently sent by Chaithrika U S <chaithrika@ti.com> but
not yet merged into the DaVinci tree.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
2009-05-15 08:59:07 +01:00
Paul Walmsley
7971687094 OMAP2xxx clock: rename clk_init_one() to clk_preinit()
Rename clk_init_one() to clk_preinit() to distinguish its function
from clk_init() and the individual struct clk init functions.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:50:30 -06:00
Artem Bityutskiy
0db4e82597 OMAP3 clock: lessen amount of noisy messages
On our system we see the following messages:

Disabling unused clock "gpt2_ick"
Disabling unused clock "gpt3_ick"
Disabling unused clock "gpt4_ick"
Disabling unused clock "gpt5_ick"
...

The messages have KERN_INFO level and if you have serial
console, they normally go there. I do not think it is good
idea to print that much stuff there. Moreover, messages
are not properly prefixed and for mortals it is not
immeadietly clear where they come from.

Let's give them debugging level instead.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Paul Walmsley <paul@pwsan.com>
[paul@pwsan.com: trimmed debugging output in patch description]
2009-05-12 17:34:40 -06:00
Paul Walmsley
b7aee4bfa7 OMAP3 clock: use pr_debug() rather than pr_info() in some clock change code
The CORE DPLL M2 frequency change code should use pr_debug(), not
pr_info(), for its debug messages.  Same with
omap2_clksel_round_rate_div().  While here, convert a few printk(KERN_ERR ..
into pr_err().

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:10 -06:00
Paul Walmsley
4519c2bf43 OMAP3 clock: only unlock SDRC DLL if SDRC clk < 83MHz
According to the 34xx TRM Rev. K section 11.2.4.4.11.1 "Purpose of the
DLL/CDL Module," the SDRC delay-locked-loop can be locked at any SDRC
clock frequency from 83MHz to 166MHz.  CDP code unconditionally
unlocked the DLL whenever shifting to a lower SDRC speed, but this
seems unnecessary and error-prone, as the DLL is no longer able to
compensate for process, voltage, and temperature variations.  Instead,
only unlock the DLL when the SDRC clock rate would be less than 83MHz.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:10 -06:00
Paul Walmsley
b2abb271a5 OMAP3 SRAM: renumber registers to make space for argument passing
Renumber registers in omap3_sram_configure_core_dpll() assembly code to
make space for additional parameters.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:10 -06:00
Paul Walmsley
98cfe5abf2 OMAP3 SDRC: initialize SDRC_POWER at boot
Initialize SDRC_POWER to a known-good setting when the kernel boots.
Necessary since some bootloaders don't initialize SDRC_POWER properly.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:09 -06:00
Paul Walmsley
fa0406a8d8 OMAP3 SRAM: clear the SDRC PWRENA bit during SDRC frequency change
Clear the SDRC_POWER.PWRENA bit before putting the SDRAM into self-refresh
mode.  This prevents the SDRC from attempting to power off the SDRAM,
which can cause the system to hang.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:09 -06:00
Paul Walmsley
d75d9e73cd OMAP3 clock: add interconnect barriers to CORE DPLL M2 change
Where necessary, add interconnect barriers to force posted writes to
complete before continuing.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
2009-05-12 17:27:09 -06:00
Paul Walmsley
69d4255b13 OMAP3 SRAM: add ARM barriers to omap3_sram_configure_core_dpll
Add more barriers in the SRAM CORE DPLL M2 divider change code.

- Add a DSB SY after the function's entry point to flush all cached
  and buffered writes and wait for the interconnect to claim that they
  have completed[1].  The idea here is to force all delayed write
  traffic going to the SDRAM to at least post to the L3 interconnect
  before continuing.  If these writes are allowed to occur after the
  SDRC is idled, the writes will not be acknowledged and the ARM will
  stall.

  Note that in this case, it does not matter if the writes actually
  complete to the SDRAM - it is only necessary for the writes to leave
  the ARM itself.  If the writes are posted by the interconnect when
  the SDRC goes into idle, the writes will be delayed until the SDRC
  returns from idle[2].  If the SDRC is in the middle of a write when
  it is requested to enter idle, the SDRC will not acknowledge the
  idle request until the writes complete to the SDRAM.[3]

  The old-style DMB in sdram_in_selfrefresh is now superfluous, so,
  remove it.

- Add an ISB before the function's exit point to prevent the ARM from
  speculatively executing into SDRAM before the SDRAM is enabled[4].

...

1. ARMv7 ARM (DDI 0406A) A3-47, A3-48.

2. Private communication with Richard Woodruff <r-woodruff2@ti.com>.

3. Private communication with Richard Woodruff <r-woodruff2@ti.com>.

4. ARMv7 ARM (DDI 0406A) A3-48.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
2009-05-12 17:27:09 -06:00