[PATCH V3] ARM: imx: use outer_disable/resume for low power

[Peng Fan]

Use outer_disable/resume for suspend/resume and low power idle.
With the two APIs used, code could be easy to extend to introduce
l2c_write_sec for i.MX platforms when moving Linux Kernel
runs in non-secure world.

The cache sync operation and l2c310_early_resume in suspend-imx6.S
are kept. According to PL310 TRM for dormant mode: "The external
power controller asserts the reset. Ensure the cache controller
is placed back into run mode prior to the L1 masters.". So keep
l2c310_early_resume.

Another reason is alought L2 controller lose power, L2 memory not lose
power. If l2c310_early_resume removed, outer_resume will do invalidation
which may corrupt data. To keep safe, the cache sync operation is also
kept.

Signed-off-by: Peng Fan <peng.fan@xxxxxxx>
Cc: Shawn Guo <shawnguo@xxxxxxxxxx>
Cc: Sascha Hauer <kernel@xxxxxxxxxxxxxx>
Cc: Fabio Estevam <fabio.estevam@xxxxxxx>
Cc: Dong Aisheng <aisheng.dong@xxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
---

V3:
 Continue fix 6SX low power idle. Because L2 memory not lose power,
 outer_disable seems not clearly flush all the data or flush l1 -> flush l2
 ->cache sync must be followed, outer_resume will invalidate
 the cache, which corrupt data and cause issues. So in V3, only
 add outer_disable/resume to make it simple.
 Add more commit log.
 Based on Shawn/for-next.
V2:
  Fix 6SX booting. The V1 patch does not take 6SX low power idle into
  consideration.

 arch/arm/mach-imx/cpuidle-imx6sx.c | 2 ++
 arch/arm/mach-imx/pm-imx6.c        | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/arch/arm/mach-imx/cpuidle-imx6sx.c b/arch/arm/mach-imx/cpuidle-imx6sx.c
index c5a5c3a70ab1..b35841d133dc 100644
--- a/arch/arm/mach-imx/cpuidle-imx6sx.c
+++ b/arch/arm/mach-imx/cpuidle-imx6sx.c
@@ -49,7 +49,9 @@ static int imx6sx_enter_wait(struct cpuidle_device *dev,
 		cpu_pm_enter();
 		cpu_cluster_pm_enter();
 
+		outer_disable();
 		cpu_suspend(0, imx6sx_idle_finish);
+		outer_resume();
 
 		cpu_cluster_pm_exit();
 		cpu_pm_exit();
diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index ecdf071653d4..153a0afc7645 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -392,8 +392,10 @@ static int imx6q_pm_enter(suspend_state_t state)
 			imx6_enable_rbc(true);
 		imx_gpc_pre_suspend(true);
 		imx_anatop_pre_suspend();
+		outer_disable();
 		/* Zzz ... */
 		cpu_suspend(0, imx6q_suspend_finish);
+		outer_resume();
 		if (cpu_is_imx6q() || cpu_is_imx6dl())
 			imx_smp_prepare();
 		imx_anatop_post_resume();
-- 
2.14.1