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From: Sylvain Rochet <sylvain.rochet@finsecur.com>
To: Wenyou Yang <wenyou.yang@atmel.com>
Cc: nicolas.ferre@atmel.com, 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 11:36:05 +0100 [thread overview]
Message-ID: <20150126103605.GA20837@gradator.net> (raw)
In-Reply-To: <1422265139-23011-1-git-send-email-wenyou.yang@atmel.com>
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 :-)
Sylvain
next prev parent reply other threads:[~2015-01-26 10:36 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 [this message]
2015-01-26 13:34 ` Nicolas Ferre
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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