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From: Wenyou Yang <wenyou.yang@atmel.com>
To: <nicolas.ferre@atmel.com>, <linux@arm.linux.org.uk>
Cc: <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>,
	<alexandre.belloni@free-electrons.com>,
	<sylvain.rochet@finsecur.com>, <peda@axentia.se>,
	<wenyou.yang@atmel.com>, <Patrice.VILCHEZ@atmel.com>
Subject: [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7
Date: Mon, 26 Jan 2015 18:06:01 +0800	[thread overview]
Message-ID: <1422266761-24487-1-git-send-email-wenyou.yang@atmel.com> (raw)
In-Reply-To: <1422266617-24381-1-git-send-email-wenyou.yang@atmel.com>

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


  parent reply	other threads:[~2015-01-26 10:06 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-26 10:03 [PATCH 0/7] AT91 pm improvements for 3.20 Wenyou Yang
2015-01-26 10:04 ` [PATCH 1/7] pm: at91: achieve the memory controller's type from the dts file Wenyou Yang
2015-01-26 10:06 ` Wenyou Yang [this message]
2015-01-26 13:05   ` [PATCH 2/7] pm: at91: pm_suspend: add the WFI support for ARMv7 Sergei Shtylyov
2015-01-27  4:44     ` Yang, Wenyou
2015-01-28 11:25   ` Lorenzo Pieralisi
2015-01-29  2:36     ` Yang, Wenyou
2015-01-29 12:22       ` Lorenzo Pieralisi
2015-01-30  7:23         ` Yang, Wenyou
2015-01-30 10:17           ` Lorenzo Pieralisi
2015-01-30 10:44           ` Lorenzo Pieralisi
2015-01-26 10:06 ` [PATCH 3/7] pm: at91: pm_suspend: MOR register KEY was missing Wenyou Yang
2015-01-26 10:07 ` [PATCH 4/7] ARM: at91: enable the L2 Cache controller Wenyou Yang
2015-01-26 11:46   ` Mark Rutland
2015-01-26 12:45   ` Russell King - ARM Linux
2015-01-26 22:36   ` Alexandre Belloni
2015-01-27  5:11     ` Yang, Wenyou
2015-01-26 10:07 ` [PATCH 5/7] pm: at91: add disable/enable the L1/L2 cache while suspend/resume Wenyou Yang
2015-01-26 10:08 ` [PATCH 6/7] pm: at91: add achieve the mpddrc peripheral ID and the DDR clock ID support Wenyou Yang
2015-01-26 11:49   ` Mark Rutland
2015-01-27  5:24     ` Yang, Wenyou
2015-01-26 10:08 ` [PATCH 7/7] pm: at91: add disable/enable the mpddrc's clock and DDR clock support Wenyou Yang

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