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Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories

From Alexandre Belloni <alexandre.belloni@free-electrons.com>
Newsgroups linux.kernel
Subject Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories
Date 2016-10-13 13:20 +0200
Message-ID <srMdk-2NV-17@gated-at.bofh.it> (permalink)
References <spGlI-36r-3@gated-at.bofh.it> <spGlI-36r-11@gated-at.bofh.it> <srrse-4OM-59@gated-at.bofh.it>
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On 12/10/2016 at 14:48:27 +0200, Jean-Jacques Hiblot wrote :
> > +static void at91_lpddr_poweroff(void)
> > +{
> > +       asm volatile(
> > +               /* Align to cache lines */
> > +               ".balign 32\n\t"
> > +
> > +               "       ldr     r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
> At first sight, it looks useless. I assume it's used to preload the
> TLB before the LPDDR is turned off.
> A comment to explain why this line is useful would prevent its removal.

Yes, this is the case. I can add a comment.

Anyway, I would prefer the whole thing to run from SRAM, as a PIE
instead of relying on the cache.

> > +       ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
> > +       if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
> > +           (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
> Souldn't there be something like "pm_power_off = at91_lpddr_poweroff;" here ?
> 

Indeed


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

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Thread

[PATCH 0/2] ARM: at91: properly handle LPDDR poweroff Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-07 18:40 +0200
  [PATCH 1/2] ARM: at91: define LPDDR types Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-07 18:40 +0200
  [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-07 18:40 +0200
    Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Jean-Jacques Hiblot <jjhiblot@traphandler.com> - 2016-10-12 15:10 +0200
      Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR  memories Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-13 13:20 +0200
        Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Richard Genoud <richard.genoud@gmail.com> - 2016-10-13 14:50 +0200
        Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Jean-Jacques Hiblot <jjhiblot@traphandler.com> - 2016-10-13 14:50 +0200
          Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR  memories Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-13 15:50 +0200
            Re: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Jean-Jacques Hiblot <jjhiblot@traphandler.com> - 2016-10-13 21:00 +0200
  Re: [PATCH 0/2] ARM: at91: properly handle LPDDR poweroff Alexander Stein <alexander.stein@systec-electronic.com> - 2016-10-10 08:10 +0200
    Re: [PATCH 0/2] ARM: at91: properly handle LPDDR poweroff Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2016-10-12 13:30 +0200

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