In addition to the standard power-management technique, the OMAP5
MPU subsystem also employs an SR3-APG (mercury) power management
technology to reduce leakage.
It allows for full logic and memories retention on MPU_C0 and MPU_C1 and
is controlled by the PRCM_MPU.
Acked-by: Nishanth Menon <nm@xxxxxx>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
---
arch/arm/mach-omap2/omap-mpuss-lowpower.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
index b1441b1..d390d18 100644
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -62,6 +62,10 @@
#include "prm44xx.h"
#include "prm-regbits-44xx.h"
+/* Add defines needed for mercury mode. Refer MPU's PRM_PSCON_COUNT */
+#define PRM_PSCON_HG_EN (1 << 24)
+#define PRM_PSCON_HG_RAMPUP (1 << 25)
+
#ifdef CONFIG_SMP
struct omap4_cpu_pm_info {
@@ -337,6 +341,28 @@ int __cpuinit omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state)
return 0;
}
+/**
+ * enable_mercury_retention_mode: Enable OMAP5 mercury retention feature
+ *
+ * OMAP5 devices supports SR3-APG (mercury) power management technology to
+ * reduce leakage. It allows for full logic and memories retention on
+ * MPU_C0 and MPU_C1 and is controlled by the PRCM_MPU. The function enable
+ * the mercury retention feature.
+ */
+static void enable_mercury_retention_mode(void)
+{
+ u32 reg;
+
+ /*
+ * To enable mercury mode, both HG_EN and HG_RAMPUP needs to be
+ * enabled from PRM_PSCON_COUNT register.
+ */
+ reg = omap4_prcm_mpu_read_inst_reg(OMAP54XX_PRCM_MPU_DEVICE_INST,
+ OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
+ reg |= PRM_PSCON_HG_EN | PRM_PSCON_HG_RAMPUP;
+ omap4_prcm_mpu_write_inst_reg(reg, OMAP54XX_PRCM_MPU_DEVICE_INST,
+ OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
+}
/*
* Initialise OMAP4 MPUSS
@@ -415,6 +441,7 @@ int __init omap4_mpuss_init(void)
cpu_context_offset = OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET;
} else if (soc_is_omap54xx()) {
cpu_context_offset = OMAP54XX_RM_CPU0_CPU0_CONTEXT_OFFSET;
+ enable_mercury_retention_mode();
}
return 0;
--
1.7.9.5
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