This is a note to let you know that I've just added the patch titled
ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-omap4-fix-the-boot-regression-with-cpu_idle-enabled.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4b353a706a86598ba47307c47301c3c428b79e09 Mon Sep 17 00:00:00 2001
From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Date: Mon, 12 May 2014 17:37:59 -0400
Subject: ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled
From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
commit 4b353a706a86598ba47307c47301c3c428b79e09 upstream.
On OMAP4 panda board, there have been several bug reports about boot
hang and lock-ups with CPU_IDLE enabled. The root cause of the issue
is missing interrupts while in idle state. Commit cb7094e8 {cpuidle / omap4 :
use CPUIDLE_FLAG_TIMER_STOP flag} moved the broadcast notifiers to common
code for right reasons but on OMAP4 which suffers from a nasty ROM code
bug with GIC, commit ff999b8a {ARM: OMAP4460: Workaround for ROM bug ..},
we loose interrupts which leads to issues like lock-up, hangs etc.
Patch reverts commit cb7094 {cpuidle / omap4 : use CPUIDLE_FLAG_TIMER_STOP
flag} and 54769d6 {cpuidle: OMAP4: remove timer broadcast initialization} to
avoid the issue. With this change, OMAP4 panda boards, the mentioned
issues are getting fixed. We no longer loose interrupts which was the cause
of the regression.
Fixes: cb7094e8 (cpuidle / omap4 : use CPUIDLE_FLAG_TIMER_STOP flag)
Fixes: ff999b8a (cpuidle: OMAP4: remove timer broadcast initialization)
Cc: Roger Quadros <rogerq@xxxxxx>
Cc: Kevin Hilman <khilman@xxxxxxxxxx>
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Reported-tested-by: Roger Quadros <rogerq@xxxxxx>
Reported-tested-by: Kevin Hilman <khilman@xxxxxxxxxx>
Tested-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm/mach-omap2/cpuidle44xx.c | 25 +++++++++++++++++++++----
1 file changed, 21 insertions(+), 4 deletions(-)
--- a/arch/arm/mach-omap2/cpuidle44xx.c
+++ b/arch/arm/mach-omap2/cpuidle44xx.c
@@ -14,6 +14,7 @@
#include <linux/cpuidle.h>
#include <linux/cpu_pm.h>
#include <linux/export.h>
+#include <linux/clockchips.h>
#include <asm/cpuidle.h>
#include <asm/proc-fns.h>
@@ -83,6 +84,7 @@ static int omap_enter_idle_coupled(struc
{
struct idle_statedata *cx = state_ptr + index;
u32 mpuss_can_lose_context = 0;
+ int cpu_id = smp_processor_id();
/*
* CPU0 has to wait and stay ON until CPU1 is OFF state.
@@ -110,6 +112,8 @@ static int omap_enter_idle_coupled(struc
mpuss_can_lose_context = (cx->mpu_state == PWRDM_POWER_RET) &&
(cx->mpu_logic_state == PWRDM_POWER_OFF);
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu_id);
+
/*
* Call idle CPU PM enter notifier chain so that
* VFP and per CPU interrupt context is saved.
@@ -165,6 +169,8 @@ static int omap_enter_idle_coupled(struc
if (dev->cpu == 0 && mpuss_can_lose_context)
cpu_cluster_pm_exit();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu_id);
+
fail:
cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
cpu_done[dev->cpu] = false;
@@ -172,6 +178,16 @@ fail:
return index;
}
+/*
+ * For each cpu, setup the broadcast timer because local timers
+ * stops for the states above C1.
+ */
+static void omap_setup_broadcast_timer(void *arg)
+{
+ int cpu = smp_processor_id();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &cpu);
+}
+
static struct cpuidle_driver omap4_idle_driver = {
.name = "omap4_idle",
.owner = THIS_MODULE,
@@ -189,8 +205,7 @@ static struct cpuidle_driver omap4_idle_
/* C2 - CPU0 OFF + CPU1 OFF + MPU CSWR */
.exit_latency = 328 + 440,
.target_residency = 960,
- .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
- CPUIDLE_FLAG_TIMER_STOP,
+ .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,
.enter = omap_enter_idle_coupled,
.name = "C2",
.desc = "CPUx OFF, MPUSS CSWR",
@@ -199,8 +214,7 @@ static struct cpuidle_driver omap4_idle_
/* C3 - CPU0 OFF + CPU1 OFF + MPU OSWR */
.exit_latency = 460 + 518,
.target_residency = 1100,
- .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED |
- CPUIDLE_FLAG_TIMER_STOP,
+ .flags = CPUIDLE_FLAG_TIME_VALID | CPUIDLE_FLAG_COUPLED,
.enter = omap_enter_idle_coupled,
.name = "C3",
.desc = "CPUx OFF, MPUSS OSWR",
@@ -231,5 +245,8 @@ int __init omap4_idle_init(void)
if (!cpu_clkdm[0] || !cpu_clkdm[1])
return -ENODEV;
+ /* Configure the broadcast timer on each cpu */
+ on_each_cpu(omap_setup_broadcast_timer, NULL, 1);
+
return cpuidle_register(&omap4_idle_driver, cpu_online_mask);
}
Patches currently in stable-queue which might be from santosh.shilimkar@xxxxxx are
queue-3.14/arm-omap4-fix-the-boot-regression-with-cpu_idle-enabled.patch
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