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@xxxxxx>
Acked-by: Jean Pihet <j-pihet@xxxxxx>
Reviewed-by: Kevin Hilman <khilman@xxxxxx>
Tested-by: Vishwanath BS <vishwanath.bs@xxxxxx>
---
arch/arm/mach-omap2/omap-smp.c | 27 +++++++++++++++++++++++++++
1 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index 844ca5d..d550a44 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -27,6 +27,8 @@
#include <mach/omap4-common.h>
#include <mach/omap-secure.h>
+#include "clockdomain.h"
+
/* SCU base address */
static void __iomem *scu_base;
@@ -67,6 +69,8 @@ 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
@@ -82,6 +86,29 @@ 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);
/*
--
1.7.4.1
--
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