Re: OMAP PM question

[Tony Lindgren]

Hi,

* Renju Liu  [151220 15:00]:
> Hello all,
> 
> For omap4, I wonder how should emif be handled when suspending the entire SoC.
> 
> In playing with Robert Nelson's 4.2 kernel tree [1], I noticed that
> the suspend seems broken: the kernel, in the suspend_noirq phase,
> tries to disable the emif hwmod by calling omap_device_idle(); the
> board thus hangs. It appears to me that the DDR shouldn't be disabled
> at this moment or it needs special treatment -- in comparison, the
> AM35xx kernel switches its execution to on-chip SRAM before turning
> off the emif.
> 
> I tried to examine earlier kernels (3.2, 3.4) for omap4 to see how
> emif is power-managed. However I didn't see much useful information.

Hmm am437x is different where it's using a GPIO pin to power the memory.
That's not the case on pandaboard or typical omap2/3/4/5 boards and
seems to be limited to am33xx/am437x designs.

Things should work with current mainline, at least this works for
me on omap4430:

# rtcwake -m mem -s 5

And wakes up properly five seconds later.

And this also works for me with current mainline kernel:

#!/bin/bash

uarts=$(find /sys/class/tty/tty[SO]*/device/power/ -type d)
for uart in $uarts; do
echo 3000 > $uart/autosuspend_delay_ms 2>&1
done

uarts=$(find /sys/class/tty/tty[SO]*/power/ -type d 2>/dev/null)
for uart in $uarts; do
echo enabled > $uart/wakeup 2>&1
echo auto > $uart/control 2>&1
done

echo 1 > /sys/kernel/debug/pm_debug/enable_off_mode

And then echo mem > /sys/power/state will wake up to serial console
activity.

This is with duovero and the wakeriq patch for it's console UART that
I posted last week. AFAIK panda already has that enabled.

Regards,

Tony


> 1. https://eewiki.net/display/linuxonarm/PandaBoard
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OMAP PM question

[Renju Liu]

Hello all,

For omap4, I wonder how should emif be handled when suspending the entire SoC.

In playing with Robert Nelson's 4.2 kernel tree [1], I noticed that
the suspend seems broken: the kernel, in the suspend_noirq phase,
tries to disable the emif hwmod by calling omap_device_idle(); the
board thus hangs. It appears to me that the DDR shouldn't be disabled
at this moment or it needs special treatment -- in comparison, the
AM35xx kernel switches its execution to on-chip SRAM before turning
off the emif.

I tried to examine earlier kernels (3.2, 3.4) for omap4 to see how
emif is power-managed. However I didn't see much useful information.

Any help is appreciated.

1. https://eewiki.net/display/linuxonarm/PandaBoard

Best,
Renju
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Re: OMAP PM question

[Roger Quadros]

ext Peter Barada wrote:

Kevin,

I'm trying to port over the 2.6.30 OMAP PM branch on Logic's SOM, pulled
from just a few days ago before the rebase to 2.6.31-rc1:
http://git.kernel.org/?p=linux/kernel/git/khilman/linux-omap-pm.git;a=commit;h=e0cffc298098263630b83c458b8fce754badb9a3

Unfortunately It doesn't go into retention due to MPU_CLK being defined
as virt_pcrm_set where no virt_pcrm_set exists for OMAP3.  Once I
changed MPU_CLK to arm_fck for OMAP3 as suggested by Rajendra in
http://patchwork.kernel.org/patch/18626/  the board goes  into
retention, but it won't resume on a serial RX event.  I wonder if
Rajendra's change is correct.

1) Which config did you use on the PM tree in the 2.6.30 timeframe so
can start over from a known config/board description (that goes into
retention and comes back out) instead of what I rolled from the rx51 for
Logic's OMAP35x SOM.  Looking in arch/arm/configs, the only omap3 config
that has CONFIG_PM=y is for the evm.  Is this the one?

2) Is there anything special necessary to have a serial RX event force a
wakeup?

3) Do you have a wake-on-timer patch that works in this tree?

4) I've noticed the board hangs after a while of inactivity on the
serial power - I've tried cranking up the DEFAULT_TIMEOUT in
arch/arm/mach-omap2/serial.c to (50 * HZ), and then disabling the
timeout by echo 0  /sys/devices/platform/serial/8250.0/sleep_timeout,
but the hang still happens after a period of inactivity - characters
typed at ttyS0 don't get echoed back.  How do I enable wake on serial,
or is it on by default?



Hi Peter,

I was facing similar problems with RX51 boards. The following procedure resolved 
my problems.


1) use 2008q3 compiler (should work with 2009q1 also I guess, but I've not 
tested it)


2) Reset your tree to Kevin's PM branch. This should incorporate the latest fix
http://git.kernel.org/?p=linux/kernel/git/tmlind/linux-omap-2.6.git;a=commit;h=7e7377395d6b4576341a6939bf2179f3946f2ea0

3) use omap3_pm_defconfig, Then change the CONFIG_OMAP_LL_DEBUG_UART to suit 
your board's serial UART (1, 2 or 3) and also the CMDLINE to suit your board.


cheers,
-roger
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OMAP PM question

[Peter Barada]

Kevin,

I'm trying to port over the 2.6.30 OMAP PM branch on Logic's SOM, pulled
from just a few days ago before the rebase to 2.6.31-rc1:
http://git.kernel.org/?p=linux/kernel/git/khilman/linux-omap-pm.git;a=commit;h=e0cffc298098263630b83c458b8fce754badb9a3

Unfortunately It doesn't go into retention due to MPU_CLK being defined
as virt_pcrm_set where no virt_pcrm_set exists for OMAP3.  Once I
changed MPU_CLK to arm_fck for OMAP3 as suggested by Rajendra in
http://patchwork.kernel.org/patch/18626/  the board goes  into
retention, but it won't resume on a serial RX event.  I wonder if
Rajendra's change is correct.

1) Which config did you use on the PM tree in the 2.6.30 timeframe so
can start over from a known config/board description (that goes into
retention and comes back out) instead of what I rolled from the rx51 for
Logic's OMAP35x SOM.  Looking in arch/arm/configs, the only omap3 config
that has CONFIG_PM=y is for the evm.  Is this the one?

2) Is there anything special necessary to have a serial RX event force a
wakeup?

3) Do you have a wake-on-timer patch that works in this tree?

4) I've noticed the board hangs after a while of inactivity on the
serial power - I've tried cranking up the DEFAULT_TIMEOUT in
arch/arm/mach-omap2/serial.c to (50 * HZ), and then disabling the
timeout by echo 0  /sys/devices/platform/serial/8250.0/sleep_timeout,
but the hang still happens after a period of inactivity - characters
typed at ttyS0 don't get echoed back.  How do I enable wake on serial,
or is it on by default?

-- 
Peter Barada pet...@logicpd.com
Logic Product Development, Inc.
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