From: alexandre.belloni@free-electrons.com (Alexandre Belloni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories
Date: Thu, 13 Oct 2016 13:03:17 +0200 [thread overview]
Message-ID: <20161013110317.ee6by6njrvs53ztx@piout.net> (raw)
In-Reply-To: <CACh+v5NCxPb_U8HOeczHicCD-Wp8BqBzvc1LtCzmEXZ74Cgshw@mail.gmail.com>
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
next prev parent reply other threads:[~2016-10-13 11:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 16:34 [PATCH 0/2] ARM: at91: properly handle LPDDR poweroff Alexandre Belloni
2016-10-07 16:34 ` [PATCH 1/2] ARM: at91: define LPDDR types Alexandre Belloni
2016-10-07 16:34 ` [PATCH 2/2] power/reset: at91-poweroff: timely shitdown LPDDR memories Alexandre Belloni
2016-10-12 12:48 ` Jean-Jacques Hiblot
2016-10-13 11:03 ` Alexandre Belloni [this message]
2016-10-13 12:27 ` Jean-Jacques Hiblot
2016-10-13 12:39 ` Richard Genoud
2016-10-13 13:47 ` Alexandre Belloni
2016-10-13 15:04 ` Jean-Jacques Hiblot
2016-10-10 6:00 ` [PATCH 0/2] ARM: at91: properly handle LPDDR poweroff Alexander Stein
2016-10-12 11:17 ` Alexandre Belloni
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