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ARM: OMAP4: PM: CPU1 wakeup workaround from Low power modes

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The SGI(Software Generated Interrupts) are not wakeup capable from
low power states. This is known limitation on OMAP4 and needs to be
worked around by using software forced clockdomain wake-up. CPU0 forces
the CPU1 clockdomain to software force wakeup.

More details can be found in OMAP4430 TRM - Version J
Section :
	4.3.4.2 Power States of CPU0 and CPU1

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>
This commit is contained in:
Santosh Shilimkar 2010-06-16 22:19:49 +05:30 committed by Kevin Hilman
parent b5b4f2881f
commit e97ca477e9
1 changed files with 27 additions and 0 deletions
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27
arch/arm/mach-omap2/omap-smp.c
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@ -28,6 +28,8 @@
#include "common.h"
#include "clockdomain.h"
/* SCU base address */
static void __iomem *scu_base;
@ -68,6 +70,8 @@ void __cpuinit platform_secondary_init(unsigned int cpu)
int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
{
static struct clockdomain *cpu1_clkdm;
static bool booted;
/*
* Set synchronisation state between this boot processor
* and the secondary one
@ -83,6 +87,29 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle)
omap_modify_auxcoreboot0(0x200, 0xfffffdff);
flush_cache_all();
smp_wmb();
if (!cpu1_clkdm)
cpu1_clkdm = clkdm_lookup("mpu1_clkdm");
/*
* The SGI(Software Generated Interrupts) are not wakeup capable
* from low power states. This is known limitation on OMAP4 and
* needs to be worked around by using software forced clockdomain
* wake-up. To wakeup CPU1, CPU0 forces the CPU1 clockdomain to
* software force wakeup. The clockdomain is then put back to
* hardware supervised mode.
* More details can be found in OMAP4430 TRM - Version J
* Section :
* 4.3.4.2 Power States of CPU0 and CPU1
*/
if (booted) {
clkdm_wakeup(cpu1_clkdm);
clkdm_allow_idle(cpu1_clkdm);
} else {
dsb_sev();
booted = true;
}
gic_raise_softirq(cpumask_of(cpu), 1);
/*