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drivers: cpuidle: Don't initialize big.LITTLE driver if MCPM is unavailable 

If big.LITTLE driver is initialized even when MCPM is unavailable,
we get the below warning the first time cpu tries to enter deeper
C-states.

------------[ cut here ]------------
WARNING: CPU: 4 PID: 0 at kernel/arch/arm/common/mcpm_entry.c:130 mcpm_cpu_suspend+0x6d/0x74()
Modules linked in:
CPU: 4 PID: 0 Comm: swapper/4 Not tainted 3.19.0-rc3-00007-gaf5a2cb1ad5c-dirty #11
Hardware name: ARM-Versatile Express
[<c0013fa5>] (unwind_backtrace) from [<c001084d>] (show_stack+0x11/0x14)
[<c001084d>] (show_stack) from [<c04fe7f1>] (dump_stack+0x6d/0x78)
[<c04fe7f1>] (dump_stack) from [<c0020645>] (warn_slowpath_common+0x69/0x90)
[<c0020645>] (warn_slowpath_common) from [<c00206db>] (warn_slowpath_null+0x17/0x1c)
[<c00206db>] (warn_slowpath_null) from [<c001cbdd>] (mcpm_cpu_suspend+0x6d/0x74)
[<c001cbdd>] (mcpm_cpu_suspend) from [<c03c6919>] (bl_powerdown_finisher+0x21/0x24)
[<c03c6919>] (bl_powerdown_finisher) from [<c001218d>] (cpu_suspend_abort+0x1/0x14)
[<c001218d>] (cpu_suspend_abort) from [<00000000>] (  (null))
---[ end trace d098e3fd00000008 ]---

This patch fixes the issue by checking for the availability of MCPM
before initializing the big.LITTLE cpuidle driver

Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
This commit is contained in:
Sudeep Holla 2015-01-08 06:29:04 +00:00 committed by Daniel Lezcano
parent ec6f34e5b5
commit 194fe6f28e
1 changed files with 4 additions and 0 deletions
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4
drivers/cpuidle/cpuidle-big_little.c
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@ -182,6 +182,10 @@ static int __init bl_idle_init(void)
*/ */
if (!of_match_node(compatible_machine_match, root)) if (!of_match_node(compatible_machine_match, root))
return -ENODEV; return -ENODEV;
if (!mcpm_is_available())
return -EUNATCH;
/* /*
* For now the differentiation between little and big cores * For now the differentiation between little and big cores
* is based on the part number. A7 cores are considered little * is based on the part number. A7 cores are considered little