Hi,

On 23/01/2015 at 20:17:19 +0100, Sylvain Rochet wrote :

Hello Wenyou,

On Tue, Jan 20, 2015 at 04:17:01PM +0800, Wenyou Yang wrote:

quoted

diff --git a/arch/arm/mach-at91/pm_suspend.S b/arch/arm/mach-at91/pm_suspend.S
new file mode 100644
index 0000000..420e730
--- /dev/null

quoted

+	/* Turn off the main oscillator */
+	ldr	tmp1, [pmc, #AT91_CKGR_MOR]
+	bic	tmp1, tmp1, #AT91_PMC_MOSCEN

at91sam9x5 and probably others need a key here:
	orr     tmp1, tmp1, #AT91_PMC_KEY

quoted

+	str	tmp1, [pmc, #AT91_CKGR_MOR]

quoted

+	/* Wait for interrupt */
+	mcr	p15, 0, tmp1, c7, c0, 4

The linux-3.10-at91 branch uses a different approach which seem 
necessary for newer board, you probably forget to merge the following:

/*
 * Put the processor to enter into Standby mode, wait for interrupt to wakeup
 */
	.macro _do_wfi

#if defined(CONFIG_CPU_V7)
	dsb

	/* Disable the processor clock */
	mov	tmp1, #AT91_PMC_PCK
	str	tmp1, [pmc, #AT91_PMC_SCDR]

	wfi		@ Wait For Interrupt
#else
	mcr	p15, 0, tmp1, c7, c0, 4
#endif

	.endm

	.text

ENTRY(at91_slow_clock)
(...)
	/* Wait for interrupt */
	_do_wfi
(...)

quoted

+	/* Turn on the main oscillator */
+	ldr	tmp1, [pmc, #AT91_CKGR_MOR]
+	orr	tmp1, tmp1, #AT91_PMC_MOSCEN

at91sam9x5 and probably others need a key here:
        orr     tmp1, tmp1, #AT91_PMC_KEY

quoted

+	str	tmp1, [pmc, #AT91_CKGR_MOR]

What about the following parts which are also in linux-3.10-at91 branch 
but not in this rework, are they necessary ?

sdr_sr_done:
	/* Disable MPDDRC Clock*/
	cmp	ddrcid, #0
	beq	2f
	bic	tmp2, ddrcid, #0xe0 /* fetch lowest 5 bits */
	mov	tmp1, #0x01
	mov	tmp1, tmp1, lsl tmp2

	tst	ddrcid, #0x20	/* > 32 ? */
	beq	1f
	str	tmp1, [pmc, #AT91_PMC_PCDR1]
	b	2f
1:
	str	tmp1, [pmc, #AT91_PMC_PCDR]
2:

	/* Disable DDR Clock */
	mov 	tmp1, #AT91_PMC_SYS_DDR
	str	tmp1, [pmc, #AT91_PMC_SCDR]




	/* Enable MPDDRC Clock*/
	cmp	ddrcid, #0
	beq	4f
	bic	tmp2, ddrcid, #0xe0 /* fetch lowest 5 bits */
	mov	tmp1, #0x01
	mov	tmp1, tmp1, lsl tmp2

	tst	ddrcid, #0x20	/* > 32 ? */
	beq	3f
	str	tmp1, [pmc, #AT91_PMC_PCER1]
	b	4f
3:
	str	tmp1, [pmc, #AT91_PMC_PCER]
4:

	/* Enable DDR clock */
	mov 	tmp1, #AT91_PMC_SYS_DDR
	str	tmp1, [pmc, #AT91_PMC_SCER]

This is a rework, what is part of linux-3.10-at91 and not yet present in
mainline should be part of a following series. I would prefer not mixing
reworks and "new" functionalities (they have been present in the atmel
tree for a while but never mainlined). I would say that PM on 9x5, n12
and sama5 in mainline is clearly not well tested and is lagging behind
the atmel tree.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com