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From: Nicolas Ferre <nicolas.ferre@atmel.com>
To: Sylvain Rochet <sylvain.rochet@finsecur.com>,
Wenyou Yang <wenyou.yang@atmel.com>
Cc: <linux@arm.linux.org.uk>, <linux-arm-kernel@lists.infradead.org>,
<linux-kernel@vger.kernel.org>,
<alexandre.belloni@free-electrons.com>, <peda@axentia.se>
Subject: Re: [PATCH v2 02/12] pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories.
Date: Mon, 26 Jan 2015 14:34:38 +0100 [thread overview]
Message-ID: <54C6426E.9090808@atmel.com> (raw)
In-Reply-To: <20150126103605.GA20837@gradator.net>
Le 26/01/2015 11:36, Sylvain Rochet a écrit :
> Hello Wenyou,
>
> On Mon, Jan 26, 2015 at 05:38:59PM +0800, Wenyou Yang wrote:
>> From: Peter Rosin <peda@axentia.se>
>>
>> The DDRSDR controller fails miserably to put LPDDR1 memories in
>> self-refresh. Force the controller to think it has DDR2 memories
>> during the self-refresh period, as the DDR2 self-refresh spec is
>> equivalent to LPDDR1, and is correctly implemented in the
>> controller.
>>
>> Assume that the second controller has the same fault, but that is
>> untested.
>>
>> Signed-off-by: Peter Rosin <peda@axentia.se>
>> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
>> ---
>> arch/arm/mach-at91/pm_slowclock.S | 43 +++++++++++++++++++++++++++++++-----
>> include/soc/at91/at91sam9_ddrsdr.h | 2 +-
>> 2 files changed, 39 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/arm/mach-at91/pm_slowclock.S b/arch/arm/mach-at91/pm_slowclock.S
>> index e2bfaf5..1155217 100644
>> --- a/arch/arm/mach-at91/pm_slowclock.S
>> +++ b/arch/arm/mach-at91/pm_slowclock.S
>> @@ -100,6 +100,16 @@ ddr_sr_enable:
>> cmp memctrl, #AT91_MEMCTRL_DDRSDR
>> bne sdr_sr_enable
>>
>> + /* LPDDR1 --> force DDR2 mode during self-refresh */
>
> I think we should explain we are dealing with an errata here, this is
> not obvious at first sight, the patch summary may find its place here :-)
True but the problem is that this errata is not public yet, it will be
in a couple of weeks.
I have the feeling though that the commit message is pretty clear. We'll
maybe add that it"s an actual errata.
Bye,
--
Nicolas Ferre
next prev parent reply other threads:[~2015-01-26 13:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-26 9:36 [PATCH v2 00/12] AT91 pm cleanup for 3.20 Wenyou Yang
2015-01-26 9:37 ` [PATCH v2 01/12] pm: at91: pm_slowclock: improve reliability of suspend/resume Wenyou Yang
2015-01-26 14:54 ` [PATCH v2 0/2] " Sylvain Rochet
2015-01-26 14:54 ` [PATCH v2 1/2] pm: at91: pm_slowclock: fix suspend/resume hang up in timeouts Sylvain Rochet
2015-01-26 14:54 ` [PATCH v2 2/2] pm: at91: pm_slowclock: remove clocks which are already stopped when entering slow clock mode Sylvain Rochet
2015-01-26 9:38 ` [PATCH v2 02/12] pm: at91: Workaround DDRSDRC self-refresh bug with LPDDR1 memories Wenyou Yang
2015-01-26 10:36 ` Sylvain Rochet
2015-01-26 13:34 ` Nicolas Ferre [this message]
2015-01-26 13:44 ` Sylvain Rochet
2015-01-26 15:58 ` Peter Rosin
2015-01-26 16:04 ` Nicolas Ferre
2015-01-26 16:11 ` Sylvain Rochet
2015-01-26 9:39 ` [PATCH v2 03/12] pm: at91: pm_slowclock: remove the unused code related with SLOWDOWN_MASTER_CLOCK Wenyou Yang
2015-01-26 9:40 ` [PATCH v2 04/12] pm: at91: move the copying the sram function to the sram initializationi phase Wenyou Yang
2015-01-26 12:57 ` Sergei Shtylyov
2015-01-27 3:27 ` Yang, Wenyou
2015-01-26 9:40 ` [PATCH v2 05/12] ARM: at91: move select SRAM to ARCH_AT91 Wenyou Yang
2015-01-26 9:41 ` [PATCH v2 06/12] pm: at91: remove the config item CONFIG_AT91_SLOW_CLOCK Wenyou Yang
2015-01-26 9:42 ` [PATCH v2 07/12] pm: at91: the standby mode uses the same sram function as the suspend to memory mode Wenyou Yang
2015-01-26 10:09 ` Sylvain Rochet
2015-01-27 4:44 ` Yang, Wenyou
2015-01-26 9:42 ` [PATCH v2 08/12] pm: at91: rename file name: pm_slowclock.S -->pm_suspend.S Wenyou Yang
2015-01-26 9:43 ` [PATCH v2 09/12] pm: at91: rename function name: at91_slow_clock()-->at91_pm_suspend_sram_fn Wenyou Yang
2015-01-26 9:44 ` [PATCH v2 10/12] pm: at91: remove the at91_xxx_standby() function definitions in the pm.h Wenyou Yang
2015-01-26 9:45 ` [PATCH v2 11/12] pm: at91: setup: remove the struct ramc_ids .data at91_xxx_standby members Wenyou Yang
2015-01-26 9:45 ` [PATCH v2 12/12] pm: at91: amend the pm_suspend entry for at91_cpuidle_device Wenyou Yang
2015-01-26 9:55 ` [PATCH v2 00/12] AT91 pm cleanup for 3.20 Sylvain Rochet
2015-01-27 2:58 ` Yang, Wenyou
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