Re: [PATCH 08/12] pm: at91: rename file name: pm_slowclock.S -->pm_suspend.S

From: Sylvain Rochet
Date: Fri Jan 23 2015 - 14:17:40 EST


Hello Wenyou,

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


> + /* 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

> + str tmp1, [pmc, #AT91_CKGR_MOR]



> + /* 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
(...)




> + /* 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

> + 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]



Sylvain
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