[PATCH v3 0/3] MCPM/TC2 support for CPU powerdown synchronisation
Vijay Kilari
vijay.kilari at gmail.com
Tue Nov 5 00:27:49 EST 2013
Hi Dave,
After picking required patches for 3.10, kexec & kdump works
on ARM VE
I have set SCC 0x700 to 0x0032F003 and thumb2 is disabled
Thanks
Vijay
On Fri, Oct 25, 2013 at 9:16 PM, Dave Martin <Dave.Martin at arm.com> wrote:
> On Thu, Oct 24, 2013 at 06:19:42PM +0530, Vijay Kilari wrote:
>> Sorry. Below is the right DCC configuration for SCC 700
>> SCC: 0x700 0x0032F003 ;CFGRW48 - [25:24]Boot CPU [28]Boot
>>
>> On Thu, Oct 24, 2013 at 6:18 PM, Vijay Kilari <vijay.kilari at gmail.com> wrote:
>> > Hi Dave Martin,
>> >
>> > With the below configuration, I tried to check cpu hotplug as this
>> > is prerequisite for kexec.
>> > I see cpu hotplug fails. hot-unplug is OK but hot plug-in fails.
>
> Thanks for giving this a try.
>
>> > Below is my DCC board configuration
>
>
> I've attached my board.txt.
>
> The only obvious difference that I think should have an impact is that
> bit 13 in SCC 0x700 needs to be 1 in order for the non-boot cluster to
> be powered down on startup.
>
> In my board.txt, SCC 0x700 has the value 0x0032F003 -- you have that,
> but it's commented out.
>
> What happens if you set that bit, and make no other changes to your
> config?
>
> [more comments below]
>
>> >
>> > SCC REGISTERS]
>> > TOTALSCCS: 32 ;Total Number of SCC registers
>> > SCC: 0x018 0x1FFFFFFF
>> > SCC: 0x01C 0xFF00FF00 ;CFGRW3 - SMC CS6/7 N/U
>> > SCC: 0x118 0x01CD1011 ;CFGRW17 - HDLCD PLL external bypass
>> > ;SCC: 0x700 0x1032F003 ;CFGRW48 - [25:24]Boot CPU [28]Boot
>> > Cluster (default CA7_0)
>> > SCC: 0x700 0x0032D003 ;CFGRW48 - [25:24]Boot CPU [28]Boot
>> > Cluster (default CA7_0)
>> > ; Bootmon configuration:
>> > ; [15]: A7 Event stream
>> > generation (default: disabled)
>> > ; [14]: A15 Event stream
>> > generation (default: disabled)
>> > ; [13]: Power down the
>> > non-boot cluster (default: disabled)
>> > ; [12]: Use per-cpu mailboxes
>> > for power management (default: disabled)
>> > ; [11]: A15 executes WFEs as
>> > nops (default: disabled)
>> > ; [ 4]: Erase UEFI variable
>> > storage in NOR flash
>> >
>> > SCC: 0x400 0x33330c00 ;CFGREG41 - A15 configuration register
>> > 0 (Default 0x33330c80)
>> > ; [29:28] SPNIDEN
>> > ; [25:24] SPIDEN
>> > ; [21:20] NIDEN
>> > ; [17:16] DBGEN
>> > ; [13:12] CFGTE
>> > ; [9:8] VINITHI_CORE
>> > ; [7] IMINLN
>> > ; [3:0] CLUSTER_ID
>> >
>> >
>> > ;Power management interface
>> >
>> > SCC: 0xC00 0x00000005 ;Control: [0]PMI_EN [1]DBG_EN [2]SPC_SYSCFG
>> > SCC: 0xC04 0x000005DC ;Latency in uS max: [15:0]DVFS [31:16]PWRUP
>> >
>> >
>> > On Mon, Oct 21, 2013 at 6:47 PM, Vijay Kilari <vijay.kilari at gmail.com> wrote:
>> >> Hi Dave Martin,
>> >>
>> >> On which kernel base this kexec is tested? is it 3.10 or 3.12?
>> >> can you please share your git (public) if available?
>
> I don't have a public git tree right now (that's on my todo list).
>
> I tested the latest post of the series (v4) with v3.12-rc3.
>
>> >> I tested using 3.10 + TC2 patches. However I see sometimes kexec fails
>> >> to reboot and hangs at very early stage (log below)
>> >>
>> >> root at armeb-cortex-a15:/# kexec -e
>> >> [ 59.311559] Starting new kernel
>
> I don't know why this should happen. There is a known bug affecting
> kexec when the initial kernel is Thumb (i.e., CONFIG_THUMB2_KERNEL=y).
> What's your config?
>
> Do you get any extra output if you enable the debug UART earlyprintk?
>
>
> Note that in the kernel config, you'll need CONFIG_NR_CPUS=5. The
> default is 4, which may result in the final A7 CPU not being properly
> parked across kexec -- I suggest you try changing this too.
>
> Cheers
> ---Dave
>
>> >>
>> >> Thanks
>> >> Vijay
>> >>
>> >> Message: 2
>> >> Date: Tue, 1 Oct 2013 18:15:15 +0100
>> >> From: Dave Martin <Dave.Martin at arm.com>
>> >> To: linux-arm-kernel at lists.infradead.org
>> >> Cc: Nicolas Pitre <nicolas.pitre at linaro.org>, Lorenzo Pieralisi
>> >> <Lorenzo.Pieralisi at arm.com>, Pawel Moll <Pawel.Moll at arm.com>, Sudeep
>> >> KarkadaNagesha <Sudeep.KarkadaNagesha at arm.com
>> >>>, Will Deacon
>> >> <Will.Deacon at arm.com>, Dave Martin <Dave.Martin at arm.com>
>> >> Subject: [PATCH v3 0/3] MCPM/TC2 support for CPU powerdown
>> >> synchronisation
>> >> Message-ID: <1380647718-9178-1-git-send-email-Dave.Martin at arm.com>
>> >>
>> >> This series adds MCPM support for detecting when a CPU is safely powered
>> >> down, and provides an implementation for TC2.
>> >>
>> >> It should be possible to implement the same thing for PSCI using the
>> >> AFFINITY_INFO call (I need to check the semantics with Charles)
>> >>
>> >> This is sufficient to for working kexec with real power management on
>> >> TC2. To test it, you'll also need:
>> >>
>> >> * CONFIG_KEXEC=y
>> >> * CONFIG_PROC_DEVICE_TREE=y
>> >> * CONFIG_MCPM=y
>> >> * CONFIG_ARCH_VEXPRESS_TC2_PM=y
>> >> * sufficiently new kexec-tools
>> >> (git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
>> >> v2.0.4 worked for me)
>> >>
>> >> This build on Nico's patch
>> >> http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=7842/1
>> >> (MCPM: don't explode if invoked without being initialized first)
>> >>
>> >> To prevent CPUs from running off into the weeds across kexec, this
>> >> series requires Lorenzo's patch
>> >> http://lists.infradead.org/pipermail/linux-arm-kernel/2013-September/200917.html
>> >> (arm: vexpress: tc2: fix hotplug/idle/kexec race on cluster power down).
>> >>
>> >> Changes since v2:
>> >>
>> >> * Return a proper failure code if mcpm_cpu_power_down_finish() is
>> >> called with no mcpm platforms_ops registered, or a NULL
>> >> power_down_finish() method. (Thanks again Nico)
>> >>
>> >> * Minor refactoring of the loop in tc2_pm_power_down_finish() to
>> >> avoid the goto.
>> >>
>> >> Changes between v1 and v2:
>> >>
>> >> * "Fix" erroneous documentation comment by switching to -errno return
>> >> value convention for power_down_finish(), which is more informative.
>> >> tc2_pm now returns -ETIMEDOUT on timeout. The return is adapted to
>> >> bool convention on return from smp_ops.cpu_kill() instead. (Thanks,
>> >> Nico).
>> >>
>> >> * For consistency, BUG_ON out of range cpu or cluster values
>> >> tc2_pm_power_down_finish(), as for tc2_pm_power_down().
>> >>
>> >> Changes between RFC and v1:
>> >>
>> >> * Print a big fat warning instead of branching to null if the
>> >> power_down_finish() method is not supplied by the backend, or not
>> >> registered.
>> >>
>> >> * Add a generous timeout of 1 second for the TC2 implementation.
>> >>
>> >> * Relax the polling interval to 10ms for TC2, since the need to poll
>> >> more than once is rare and this is not a performance-critical path.
>> >>
>> >> * Fix some silly typos.
>> >>
>> >>
>> >> Dave Martin (3):
>> >> ARM: mcpm: Factor out logical-to-physical CPU translation
>> >> ARM: mcpm: Implement cpu_kill() to synchronise on powerdown
>> >> ARM: vexpress/TC2: Implement MCPM power_down_finish()
>> >>
>> >> arch/arm/common/mcpm_entry.c | 15 +++++++++
>> >> arch/arm/common/mcpm_platsmp.c | 27 +++++++++++++---
>> >> arch/arm/include/asm/mcpm.h | 31 ++++++++++++++++++
>> >> arch/arm/mach-vexpress/spc.c | 39 +++++++++++++++++++++++
>> >> arch/arm/mach-vexpress/spc.h | 1 +
>> >> arch/arm/mach-vexpress/tc2_pm.c | 66 ++++++++++++++++++++++++++++++++++++---
>> >> 6 files changed, 170 insertions(+), 9 deletions(-)
>> >>
>> >> --
>> >> 1.7.9.5
>>
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