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From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Sylvain Rochet <sylvain.rochet@finsecur.com>
Cc: Wenyou Yang <wenyou.yang@atmel.com>,
	nicolas.ferre@atmel.com, linux@arm.linux.org.uk,
	linux-kernel@vger.kernel.org, peda@axentia.se,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 08/12] pm: at91: rename file name: pm_slowclock.S -->pm_suspend.S
Date: Sat, 24 Jan 2015 00:17:38 +0100	[thread overview]
Message-ID: <20150123231738.GB32318@piout.net> (raw)
In-Reply-To: <20150123191719.GA29601@gradator.net>

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:
> > 
> > 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]
> 
> 

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

  reply	other threads:[~2015-01-23 23:17 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-20  8:16 [PATCH 00/12] AT91 pm cleanup for 3.20 Wenyou Yang
2015-01-20  8:16 ` [PATCH 01/12] pm: at91: pm_slowclock: improve reliability of suspend/resume Wenyou Yang
2015-01-20  8:16 ` [PATCH 02/12] pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories Wenyou Yang
2015-01-20  8:16 ` [PATCH 03/12] pm: at91: pm_slowclock: remove the unused code related with SLOWDOWN_MASTER_CLOCK Wenyou Yang
2015-01-20  8:16 ` [PATCH 04/12] pm: at91: move the copying the sram function to the sram initializationi phase Wenyou Yang
2015-01-20  8:16 ` [PATCH 05/12] ARM: at91: move select SRAM to ARCH_AT91 Wenyou Yang
2015-01-23 10:24   ` Alexandre Belloni
2015-01-26  1:10     ` Yang, Wenyou
2015-01-20  8:16 ` [PATCH 06/12] pm: at91: remove the config item CONFIG_AT91_SLOW_CLOCK Wenyou Yang
2015-01-20  8:17 ` [PATCH 07/12] pm: at91: the standby mode uses the same sram function as the suspend to memory mode Wenyou Yang
2015-01-23 10:30   ` Alexandre Belloni
2015-01-23 16:50   ` Sylvain Rochet
2015-01-23 23:13     ` Alexandre Belloni
2015-01-27  3:08       ` Yang, Wenyou
2015-01-23 17:32   ` Sylvain Rochet
2015-01-23 23:02     ` Alexandre Belloni
2015-01-26  3:08       ` Yang, Wenyou
2015-01-26  3:06     ` Yang, Wenyou
2015-01-20  8:17 ` [PATCH 08/12] pm: at91: rename file name: pm_slowclock.S -->pm_suspend.S Wenyou Yang
2015-01-23 19:17   ` Sylvain Rochet
2015-01-23 23:17     ` Alexandre Belloni [this message]
2015-01-25 13:30       ` Sylvain Rochet
2015-01-26  1:25     ` Yang, Wenyou
2015-01-20  8:17 ` [PATCH 09/12] pm: at91: rename function name: at91_slow_clock()-->at91_pm_suspend_sram_fn Wenyou Yang
2015-01-20  8:24 ` Wenyou Yang
2015-01-20  8:24 ` [PATCH 10/12] pm: at91: remove the at91_xxx_standby() function definitions in the pm.h Wenyou Yang
2015-01-20  8:25 ` [PATCH 11/12] pm: at91: remove the struct ramc_ids .data at91_xxx_standby members Wenyou Yang
2015-01-20  8:26 ` [PATCH 12/12] pm: at91: amend the pm_suspend entry for at91_cpuidle_device Wenyou Yang

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