Add the WFI support to put the cpu to the sleep state.
In the meanwhile, disable the processor's clock.
Signed-off-by: Wenyou Yang <wenyou.y...@atmel.com>
---
arch/arm/mach-at91/pm_suspend.S | 49 ++++++++++++++++++++++++++++++++++++++-
1 file changed, 48 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
index 122a3f1..aed6903 100644
--- a/arch/arm/mach-at91/pm_suspend.S
+++ b/arch/arm/mach-at91/pm_suspend.S
@@ -53,6 +53,53 @@ mode .req r6
beq 1b
.endm
+/*
+ * Put the processor to enter the WFI state
+ */
+ .macro _do_wfi
+
+#if defined(CONFIG_CPU_V7)
+ /*
+ * Execute an ISB instruction to flush the pipeline to ensure
+ * that all of operations have beem completed.
+ */
+ isb
+
+ dsb
+ dmb
+
+ /* Disable the processor's clock */
+ mov tmp1, #AT91_PMC_PCK
+ str tmp1, [pmc, #AT91_PMC_SCDR]
+
+ wfi
+
+ /*
+ * CPU can speculatively prefetch the instructions
+ * so add NOPs after WFI. Sixteen NOPs as Cortex-A5 pipeline.
+ */
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+ nop
+#else
+ mcr p15, 0, tmp1, c7, c0, 4
+#endif
+
+ .endm
+
.text
/*
@@ -181,7 +228,7 @@ sdr_sr_done:
skip_disable_main_clock:
/* Wait for interrupt */
- mcr p15, 0, tmp1, c7, c0, 4
+ _do_wfi
tst mode, #AT91_PM_SLOW_CLOCK
beq skip_enable_main_clock
--
1.7.9.5
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