Messages in this thread Patch in this message | | | From | Wenyou Yang <> | Subject | [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7 | Date | Mon, 26 Jan 2015 18:06:01 +0800 |
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Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com> --- arch/arm/mach-at91/pm_suspend.S | 54 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 53 insertions(+), 1 deletion(-)
diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S index 122a3f1..e796722 100644 --- a/arch/arm/mach-at91/pm_suspend.S +++ b/arch/arm/mach-at91/pm_suspend.S @@ -53,6 +53,58 @@ 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 + + /* + * Execute an ISB instruction to ensure that all of the + * CP15 register changes have been committed. + */ + dsb + dmb + + /* Disable the processor's clock */ + mov tmp1, #AT91_PMC_PCK + str tmp1, [pmc, #AT91_PMC_SCDR] + + /* Execute a WFI instruction */ + wfi @ Wait For Interrupt + + /* + * CPU can specualatively 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 +233,7 @@ 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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