Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4b353a70 authored by Santosh Shilimkar's avatar Santosh Shilimkar Committed by Tony Lindgren
Browse files

ARM: OMAP4: Fix the boot regression with CPU_IDLE enabled 



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 54769d65 {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: stable@vger.kernel.org # v3.9+
Cc: Roger Quadros <rogerq@ti.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Reported-tested-by: default avatarRoger Quadros <rogerq@ti.com>
Reported-tested-by: default avatarKevin Hilman <khilman@linaro.org>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarSantosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent 9ce2482f

arch/arm/mach-omap2/cpuidle44xx.c

+21 −4
Original line number Diff line number Diff line
@@ -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(struct cpuidle_device *dev, 
{

	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(struct cpuidle_device *dev, 
	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(struct cpuidle_device *dev, 
	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 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, 
	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_driver = { 
			/* 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_driver = { 
			/* 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);

}