ARM: OMAP4: PM: CPU1 wakeup workaround from Low power modes
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>
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index ee83808..c1bf3ef 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -28,6 +28,8 @@
#include "common.h"
+#include "clockdomain.h"
+
/* SCU base address */
static void __iomem *scu_base;
@@ -68,6 +70,8 @@
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 @@
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);
/*