Re: [PATCH v2 00/19] OMAP4: PM: Suspend, CPU-hotplug and CPUilde support.

[Kevin Hilman <khilman@ti.com>]

Santosh Shilimkar <santosh.shilimkar@ti.com> writes:

> V2 updates:
> Rebased on latest pm-core branch and fixes below comments
> from Kevin Hilman <khilman@ti.com>. 
> - All acronym fixes
> - Use WARN_ON() instead of BUG_ON() with graceful exit.
> - Export omap4_get_base*() rather than global address pointers
> - CPUidle prepare() hook + hotplug notifier to manage C-state dynamically.
> - Dropped debugfs way of changing C-state valid flags in favor of above.
>
> Full series with cherry-picked dependencies are available on below
> git branch. 

Can you summarize the status of the dependencies and when they will
merge?   IOW, aside from the static dependency hack, is Russell merging
all of the others?

Kevin
 
> git://dev.omapzoom.org/pub/scm/santosh/kernel-omap4-base.git
> omap4_pm_for-next_v2
>
> This series adds OMAP4 suspend and cpuidle support till MPU subsystem
> (MPUSS) off-mode. The suspend on SMP machines uses cpu-hotplug 
> infrastructure to take down the non-boot CPUs. We put secondary
> CPU(CPU1 in OMAP4) to OFF state via cpu-hotplug.
> In cpuidle too, low power states are attempted only when the
> CPU1 is put to OFF state via cpu-hotplug because of hardware
> constraints.
>
> Timer wakeup from suspend, debug pm counters and enable_off_mode
> provisions are supported as well.
>
> Special thanks to Kevin Hilman <khilman@ti.com> for doing detail
> off-the list reviews.
>
> The patches are generated against mainline 2.6.38-rc5 and tested with
> OMAP4430 SDP and OMAP4 PANDA board. Any OMAP4 board with ES2.X silicon,
> below features should work with this series. On ES1.0, these PM 
> features are not supported.
> 	1. CPU hotplug (CPU is put into off-mode)
> 	2. Suspend (Both CPUs put to off-mode and MPUSS to OFF/RET)
> 	3. CPUILDE with below C-states.
> 		C1 - CPU0 ON + CPU1 ON/OFF + MPU ON + CORE ON
> 		C2 - CPU0 ON + CPU1 OFF + MPU ON + CORE ON
> 		C3 - CPU0 OFF + CPU1 OFF + MPU CSWR + CORE ON
> 		C4 - CPU0 OFF + CPU1 OFF + MPU OFF + CORE ON
>
> In OMAP4 mpuss consist of dual Cortex-A9 with per-cpu local timers
> GIC(Generic Interrupt Controller), SCU(Snoop Control Unit) and PL310
> L2 cache controller and  CPU0/CPU1 LPRM modules.
> CPU0, CPU1 and MPUSS have there own power domain and hence multiple
> low power state combinations are possible. The CPU10 and CPU1
> Close switch Retention(CSWR) isn't supported by hardware.
> Based on various studies, measurements, hardware constraints
> and recommendations from hardware team, only below low power
> modes are supported on OMAP4.
> ----------------------------------------
> CPU0		CPU1		MPUSS
> ----------------------------------------
> ON		ON		ON
> OFF		OFF		CSWR
> OFF		OFF		OSWR 
> OFF		OFF		OFF
> -----------------------------------------
> Note: CPU0 is the master core and it is the last CPU to go down
> and first to wake-up when MPUSS low power states are attempted
>
> OSWR(Open Switch Retention) is not added as part of this series
> because it needs some power domain level support which isn't ready
> yet.
> 	http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38667.html
>
> Powerdomain INACTIVE support is also dropped because of its 
> inconsistency between OMAP4 and OMAP3.
> More information  on this thread -
> 	http://www.spinics.net/lists/linux-omap/msg45370.html
>
> This series has a dependency on few patches from below series.
> 	- GIC and SCU patches from [1] (queued up in RMK's for-next)
> 	- Local Timer patches from [2] (queued up in RMK's for-next)
> 	- Not clearing the static deps hack which is getting sorted out.
>
> The cpu-hotplug and suspend works with omap2plus_defconfig. Not to damage
> your file system with current omap2plus_defconfig, disable ARCH_OMAP2 so
> that V6 and V7 support is not built together with SMP.
> To tryout cpuidle, CONFIG_CPU_IDLE needs to be enabled in the build.
>
> CPU-HOTPLUG commands :
> 	offline : $echo 0 > /sys/devices/system/cpu/cpu1/online
> 	online : $echo 1 > /sys/devices/system/cpu/cpu1/online
>
> Suspend :$echo mem > /sys/power/state
>
> cpuilde : To trigger cpuidle deeper C-states on OMAP4, CPU1 needs
> 	to be offlied
> 	$echo 0 > /sys/devices/system/cpu/cpu1/online
>
> To see PM debug counters,
> 	$mount -t debugfs debugfs /proc/sys/debug/
> 	$cat /proc/sys/debug/pm_debug/count
> off-mode debugfs control:
> 	enable: $echo 1 > /proc/sys/debug/pm_debug/enable_off_mode
> 	disable: $echo 0 > /proc/sys/debug/pm_debug/enable_off_mode
>
> Summary:
>
> Rajendra Nayak (1):
>   OMAP4: cpuidle: Basic CPUidle support
>
> Santosh Shilimkar (18):
>   OMAP4: PM: Add omap WakeupGen module support
>   OMAP4: Use WARN_ON() instead of BUG_ON() with graceful exit
>   OMAP4: PM: Export omap4_get_base*() rather than global address
>     pointers
>   OMAP4: PM: Add SAR RAM support
>   OMAP4: PM: Add CPUX OFF mode support
>   OMAP4: PM: Initialise all the clockdomains to supported states
>   OMAP4: PM: Program CPU1 to hit OFF when off-lined
>   OMAP4: PM: CPU1 wakeup workaround from Low power modes
>   OMAP4: PM: Add GIC distributor and interface enable/disable accessory
>     api
>   OMAP4: PM: Add GIC save/restore support
>   OMAP4: PM: Add WakeupGen save/restore support
>   OMAP4: PM: Add L2 cache lowpower support
>   OMAP4: suspend: Add MPUSS RET and OFF support
>   OMAP4: pm-debug: Add wakeup timer and debug counters
>   OMAP4: cpuidle: Add MPUSS RET OFF states
>   OMAP4: cpuidle: Switch to gptimer from twd in deeper C-states.
>   OMAP4: cpuidle: Add CPU hotplug notifier and prepare() hook.
>   OMAP4: Remove un-used do_wfi() macro.
>
>  arch/arm/mach-omap2/Makefile                      |    8 +-
>  arch/arm/mach-omap2/cpuidle44xx.c                 |  352 ++++++++++++++++
>  arch/arm/mach-omap2/include/mach/omap-wakeupgen.h |   41 ++
>  arch/arm/mach-omap2/include/mach/omap4-common.h   |   73 +++-
>  arch/arm/mach-omap2/omap-hotplug.c                |   30 ++-
>  arch/arm/mach-omap2/omap-smp.c                    |   32 ++-
>  arch/arm/mach-omap2/omap-wakeupgen.c              |  319 +++++++++++++++
>  arch/arm/mach-omap2/omap4-common.c                |   85 ++++-
>  arch/arm/mach-omap2/omap4-mpuss-lowpower.c        |  451 +++++++++++++++++++++
>  arch/arm/mach-omap2/omap4-sar-layout.h            |   66 +++
>  arch/arm/mach-omap2/pm-debug.c                    |   12 +-
>  arch/arm/mach-omap2/pm.h                          |    2 +
>  arch/arm/mach-omap2/pm44xx.c                      |  119 ++++++-
>  arch/arm/mach-omap2/sleep44xx.S                   |  400 ++++++++++++++++++
>  arch/arm/plat-omap/include/plat/omap44xx.h        |    1 +
>  15 files changed, 1958 insertions(+), 33 deletions(-)
>  create mode 100644 arch/arm/mach-omap2/cpuidle44xx.c
>  create mode 100644 arch/arm/mach-omap2/include/mach/omap-wakeupgen.h
>  create mode 100644 arch/arm/mach-omap2/omap-wakeupgen.c
>  create mode 100644 arch/arm/mach-omap2/omap4-mpuss-lowpower.c
>  create mode 100644 arch/arm/mach-omap2/omap4-sar-layout.h
>  create mode 100644 arch/arm/mach-omap2/sleep44xx.S
>  
> Regrads,
> Santosh
> [1] http://www.mail-archive.com/linux-omap@vger.kernel.org/msg42939.html
> [2] http://www.spinics.net/lists/linux-omap/msg45710.html