From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
In addition to the standard power-management technique, the OMAP5 / DRA7
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. Only "Fast-mode" is supported on the
OMAP5 and DRA7 family of processors.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
[nm@xxxxxx: minor consolidation]
Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
This has a minor checkpatch warning for aligning with '(', but that
when fixed results in over 80 char warning. So choose '(' check instead :D.
arch/arm/mach-omap2/omap-mpuss-lowpower.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
index 63a1dd7..fad6e8c 100644
--- a/arch/arm/mach-omap2/omap-mpuss-lowpower.c
+++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c
@@ -321,6 +321,21 @@ int omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state)
/*
+ * Enable Mercury Fast HG retention mode by default.
+ */
+static void enable_mercury_retention_mode(void)
+{
+ u32 reg;
+
+ reg = omap4_prcm_mpu_read_inst_reg(OMAP54XX_PRCM_MPU_DEVICE_INST,
+ OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
+ /* Enable HG_EN, HG_RAMPUP = fast mode */
+ reg |= BIT(24) | BIT(25);
+ omap4_prcm_mpu_write_inst_reg(reg, OMAP54XX_PRCM_MPU_DEVICE_INST,
+ OMAP54XX_PRCM_MPU_PRM_PSCON_COUNT_OFFSET);
+}
+
+/*
* Initialise OMAP4 MPUSS
*/
int __init omap4_mpuss_init(void)
@@ -397,6 +412,7 @@ int __init omap4_mpuss_init(void)
cpu_context_offset = OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET;
} else if (soc_is_omap54xx() || soc_is_dra7xx()) {
cpu_context_offset = OMAP54XX_RM_CPU0_CPU0_CONTEXT_OFFSET;
+ enable_mercury_retention_mode();
}
return 0;
--
1.7.9.5
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