Re: [PATCH v5 05/13] pm: at91: move the copying the sram function to the sram initializationi phase

[Sergei Shtylyov]

Hello.

On 1/30/2015 9:54 AM, Yang, Wenyou wrote:

> Thank you for your review and suggestion.

   Not at all.

> > -----Original Message-----
> > From: Sergei Shtylyov [mailto:sergei.shtylyov@xxxxxxxxxxxxxxxxxx]
> > Sent: Thursday, January 29, 2015 6:11 PM
> > To: Yang, Wenyou; Ferre, Nicolas; linux@xxxxxxxxxxxxxxxx
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> > alexandre.belloni@xxxxxxxxxxxxxxxxxx; sylvain.rochet@xxxxxxxxxxxx;
> > peda@xxxxxxxxxx; linux@xxxxxxxxxxxx
> > Subject: Re: [PATCH v5 05/13] pm: at91: move the copying the sram function to
> > the sram initializationi phase

> > Hello.

> > On 1/29/2015 9:38 AM, Wenyou Yang wrote:

> > > To decrease the suspend time, move the copying the sram function to
> > > the sram initialization phase, instead of every time go to suspend.

> > > In the meanwhile, if there is no sram allocated for PM, the PM is not supported.

> > > Signed-off-by: Wenyou Yang <wenyou.yang@xxxxxxxxx>
> > > Acked-by: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx>
> > > ---
> > >    arch/arm/mach-at91/pm.c |   12 +++++++-----
> > >    1 file changed, 7 insertions(+), 5 deletions(-)

> > > diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index
> > > daa998d..6df0152 100644
> > > --- a/arch/arm/mach-at91/pm.c
> > > +++ b/arch/arm/mach-at91/pm.c
> > > @@ -163,10 +163,6 @@ static int at91_pm_enter(suspend_state_t state)
> > >    			 * turning off the main oscillator; reverse on wakeup.
> > >    			 */
> > >    			if (slow_clock) {
> > > -#ifdef CONFIG_AT91_SLOW_CLOCK
> > > -				/* copy slow_clock handler to SRAM, and call it */
> > > -				memcpy(slow_clock, at91_slow_clock,
> > > at91_slow_clock_sz);
> > > -#endif
> > >    				slow_clock(at91_pmc_base, at91_ramc_base[0],
> > >    					   at91_ramc_base[1],
> > >    					   at91_pm_data.memctrl);
> > > @@ -311,6 +307,9 @@ static void __init at91_pm_sram_init(void)
> > >    	sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base);
> > >    	slow_clock = __arm_ioremap_exec(sram_pbase, at91_slow_clock_sz,
> > > false);
> > >
> > > +	/* Copy the slow_clock handler to SRAM */
> > > +	memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);

> >      AFAIU (looking at the code above and below), __arm_ioremap_exec() can return
> > NULL and in this case memcpy() will cause kernel oops.

> Will add a condition before copying
> 	if (sram_pbase)

   I rather meant *if* (slow_clock).

[...]

> Best Regards,
> Wenyou Yang

WBR, Sergei

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