Re: [RFC/RFT PATCH v2 7/7] gpio: omap: ensure that runtime pm will disable unused gpio banks

["Grygorii.Strashko@linaro.org" <grygorii.strashko@linaro.org>]

Hi Tony,

On 05/22/2015 09:10 PM, Tony Lindgren wrote:
> * Grygorii Strashko <grygorii.strashko@linaro.org> [150522 07:37]:
>> Now there are some points related to Runtime PM usage:
>> 1) bank state doesn't need to be checked in places where
>> Rintime PM is used, bacause Runtime PM maintains its
>> own usage counter:
>>        if (!BANK_USED(bank))
>>                 pm_runtime_get_sync(bank->dev);
>> so, it's safe to drop such checks.
>>
>> 2) Such implementation is racy, because check !BANK_USED(bank)
>>     is not protected, like:
>>   CPU0				CPU1
>>   gpio_request(bankX.A)
>>   ...
>>   gpio_free(bankX.A)		gpio_request(bankX.Y)
>>
>>   and bankX can be unpowered in the middle of processing
>>   gpio_request(bankX.Y)
>>
>> 3) There is a call of pm_runtime_get_sync() in omap_gpio_irq_type(),
>> but no corresponding put. As result, GPIO devices could be
>> powered on forever if at least one GPIO was used as IRQ.
>> Hence, allow powering off GPIO banks by adding missed
>> pm_runtime_put(bank->dev) at the end of omap_gpio_irq_type().
>>
>> As, part of this change update omap2_gpio_xxxx_idle() functions
>> to use pm_runtime_force_suspend()/pm_runtime_force_resume().
>>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@linaro.org>
>> ---
>> Changes in v2:
>>   - omap2_gpio_xxxx_idle() functions switched to use
>>     pm_runtime_force_suspend()/pm_runtime_force_resume() API.
>>
>> v1:
>>      http://marc.info/?l=linux-gpio&m=142567003515626&w=2
>
> This one causes an abort during boot on at least omap3.
>
> Maybe try to get a beagleboard xm to test with? It has Ethernet
> over USB though, so that does not work with PM over NFSroot.
>
> If you want something to test with PM with mainline over
> NFSroot, maybe you can get hold of some of the better supported
> ones out of these boards:
>
> $ git grep "ethernet@gpmc" arch/arm/boot/dts/*.dts*
>
> For those Ethernet has a GPIO interrupt ;)

Sure, I'll try get beagleboard.

But, this log is very interesting :( What I can see
from it is that GPIO IRQ is triggered in the middle of
omap_sram_idle() - which shouldn't happen, because this is
cpuidle path and local IRQs should be disabled.

Am I missing smth?

>
> [    6.150238] Unhandled fault: external abort on non-linefetch (0x1028) at 0xfb05601c
> [    6.158355] pgd = c0004000
> [    6.161224] [fb05601c] *pgd=49011452(bad)
> [    6.165496] Internal error: : 1028 [#1] SMP ARM
> [    6.170288] Modules linked in:
> [    6.173522] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.0-rc4-next-20150522-00021-g6d8613e #94
> [    6.182800] Hardware name: Generic OMAP36xx (Flattened Device Tree)
> [    6.189422] task: c09b0678 ti: c09aa000 task.ti: c09aa000
> [    6.195129] PC is at omap_gpio_irq_handler+0x9c/0x234
> [    6.200469] LR is at trace_hardirqs_off+0x14/0x18
> [    6.205444] pc : [<c03d9b68>]    lr : [<c0095924>]    psr: a0000193
> [    6.205444] sp : c09abcf0  ip : c09abca8  fp : c09abd2c
> [    6.217529] r10: c06786c0  r9 : fb056000  r8 : 00000000
> [    6.223052] r7 : c59fa010  r6 : c5816300  r5 : 00000001  r4 : c59fa084
> [    6.229949] r3 : ffffffff  r2 : fb05601c  r1 : c0a2461c  r0 : 0000001c
> [    6.236846] Flags: NzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
> [    6.244628] Control: 10c5387d  Table: 80004019  DAC: 00000015
> [    6.250701] Process swapper/0 (pid: 0, stack limit = 0xc09aa218)
> [    6.257049] Stack: (0xc09abcf0 to 0xc09ac000)
> [    6.261657] bce0:                                     c09abd1c c5816300 c5802c64 fb056018
> [    6.270294] bd00: 00000000 00000031 00000031 c09adacc 00000000 00000001 c5802000 c06786c0
> [    6.278900] bd20: c09abd44 c09abd30 c00a674c c03d9ad8 00000177 c09a6110 c09abd6c c09abd48
> [    6.287536] bd40: c00a6aa0 c00a6720 c12536c0 c09abd98 c0a22f40 00000021 00000001 00000001
> [    6.296173] bd60: c09abd94 c09abd70 c0009510 c00a6a38 00001bb6 c0671c0c 20000113 ffffffff
> [    6.304809] bd80: c09abdcc 00000001 c09abdf4 c09abd98 c06725e4 c0009464 00000001 00000001
> [    6.313446] bda0: 00000000 00000000 a0000113 c09c610c a0000113 00000001 00000001 00000001
> [    6.322082] bdc0: c06786c0 c09abdf4 c09abdb0 c09abde0 c0098d44 c0671c0c 20000113 ffffffff
> [    6.330718] bde0: c09c60ac c09c610c c09abe14 c09abdf8 c002cd60 c0671bd4 c59ff200 00000000
> [    6.339355] be00: c59ff240 00000000 c09abe2c c09abe18 c002e21c c002cd2c 00000000 c5a03010
> [    6.347961] be20: c09abe44 c09abe30 c002e288 c002e1e0 c5a03010 c0a245dc c09abe5c c09abe48
> [    6.356597] be40: c0446588 c002e268 c59fa010 c0a245dc c09abe7c c09abe60 c03da610 c044654c
> [    6.365234] be60: fa306ae0 c0a64d28 00000003 00000000 c09abea4 c09abe80 c0030d4c c03da5cc
> [    6.373870] be80: 00000001 00000008 00000002 c0a64d68 c06786b8 00000001 c09abedc c09abea8
> [    6.382507] bea0: c00323a4 c0030c1c 65a0bc00 00000001 c0513e94 00000000 c09b3af4 6b46e923
> [    6.391143] bec0: 00000001 c6e75380 00000003 00000000 c09abf2c c09abee0 c0512550 c003229c
> [    6.399780] bee0: c09b3af4 000014a4 6b46e923 00000001 00000000 c09abf00 6b46e923 00000001
> [    6.408386] bf00: 00000000 c09b3af4 c6e75380 00000003 c6e75380 c09b3af4 c09adacc c0679fa8
> [    6.417022] bf20: c09abf4c c09abf30 c0512854 c05124c0 00000000 00000003 c0a5f8c8 c09ac988
> [    6.425659] bf40: c09abf64 c09abf50 c008dc40 c051281c 00007530 c09ac9ec c09abf84 c09abf68
> [    6.434295] bf60: c008de70 c008dc14 c09a7378 c09a34c4 c066cc98 c09ac8c0 c09abfac c09abf88
> [    6.442932] bf80: c06653d4 c008dc74 00000000 00000000 c06652a0 ffffffff c0a64050 c0a64000
> [    6.451568] bfa0: c09abff4 c09abfb0 c0921ccc c06652ac ffffffff ffffffff 00000000 c09216d4
> [    6.460205] bfc0: 00000000 c0975368 00000000 c0a64214 c09ac96c c0975364 c09b20f0 80004059
> [    6.468841] bfe0: 413fc082 00000000 00000000 c09abff8 8000807c c0921954 00000000 00000000
> [    6.477508] [<c03d9b68>] (omap_gpio_irq_handler) from [<c00a674c>] (generic_handle_irq+0x38/0x4c)
> [    6.486877] [<c00a674c>] (generic_handle_irq) from [<c00a6aa0>] (__handle_domain_irq+0x74/0xf0)
> [    6.496063] [<c00a6aa0>] (__handle_domain_irq) from [<c0009510>] (omap_intc_handle_irq+0xb8/0xc8)
> [    6.505432] [<c0009510>] (omap_intc_handle_irq) from [<c06725e4>] (__irq_svc+0x44/0x5c)
> [    6.513854] Exception stack(0xc09abd98 to 0xc09abde0)
> [    6.519195] bd80:                                                       00000001 00000001
> [    6.527832] bda0: 00000000 00000000 a0000113 c09c610c a0000113 00000001 00000001 00000001
> [    6.536468] bdc0: c06786c0 c09abdf4 c09abdb0 c09abde0 c0098d44 c0671c0c 20000113 ffffffff
> [    6.545104] [<c06725e4>] (__irq_svc) from [<c0671c0c>] (_raw_spin_unlock_irqrestore+0x44/0x54)
> [    6.554229] [<c0671c0c>] (_raw_spin_unlock_irqrestore) from [<c002cd60>] (omap_hwmod_idle+0x40/0x50)
> [    6.563873] [<c002cd60>] (omap_hwmod_idle) from [<c002e21c>] (omap_device_idle+0x48/0x88)
> [    6.572509] [<c002e21c>] (omap_device_idle) from [<c002e288>] (_od_runtime_suspend+0x2c/0x34)
> [    6.581512] [<c002e288>] (_od_runtime_suspend) from [<c0446588>] (pm_runtime_force_suspend+0x48/0x84)
> [    6.591247] [<c0446588>] (pm_runtime_force_suspend) from [<c03da610>] (omap2_gpio_prepare_for_idle+0x50/0x64)
> [    6.601745] [<c03da610>] (omap2_gpio_prepare_for_idle) from [<c0030d4c>] (omap_sram_idle+0x13c/0x24c)
> [    6.611480] [<c0030d4c>] (omap_sram_idle) from [<c00323a4>] (omap3_enter_idle_bm+0x114/0x228)
> [    6.620483] [<c00323a4>] (omap3_enter_idle_bm) from [<c0512550>] (cpuidle_enter_state+0x9c/0x330)
> [    6.629852] [<c0512550>] (cpuidle_enter_state) from [<c0512854>] (cpuidle_enter+0x44/0x50)
> [    6.638580] [<c0512854>] (cpuidle_enter) from [<c008dc40>] (call_cpuidle+0x38/0x60)
> [    6.646667] [<c008dc40>] (call_cpuidle) from [<c008de70>] (cpu_startup_entry+0x208/0x38c)
> [    6.655303] [<c008de70>] (cpu_startup_entry) from [<c06653d4>] (rest_init+0x134/0x170)
> [    6.663665] [<c06653d4>] (rest_init) from [<c0921ccc>] (start_kernel+0x384/0x3fc)
> [    6.671569] [<c0921ccc>] (start_kernel) from [<8000807c>] (0x8000807c)
> [    6.678466] Code: e1d101b4 e1a03315 e0822000 e2433001 (e5926000)
> [    6.684936] ---[ end trace 56ea2e3fa23d8248 ]---
>


-- 
regards,
-grygorii