From: Sascha Hauer <s.hauer@pengutronix.de>
To: Alexander Kurz <akurz@blala.de>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH 1/4] ARM: i.MX6 Wandboard: dont do MMDC Write Leveling Calibration
Date: Tue, 13 Jun 2017 09:27:29 +0200 [thread overview]
Message-ID: <20170613072729.gx63q5adesl67tmf@pengutronix.de> (raw)
In-Reply-To: <1496947297-23502-1-git-send-email-akurz@blala.de>
On Thu, Jun 08, 2017 at 08:41:34PM +0200, Alexander Kurz wrote:
> The hardware requirements to perform a write leveling calibration are
> not fulfilled by the Wandboard modules.
> IMX6DQRM §44.11.6 "Write leveling Calibration" Note2 states that the first
> bit of each data byte group (D0, D8, ..., D56) from memory must be connected
> to the same data bus bit on the controller, which is not given on the
> Wandboard modules, resulting in unpredictable calib results and breaking the
> WBQUAD 2GiB SDRAM setup. Similar restrictions exist for the i.MX6SD.
>
> Remove this calibration and use the MPWLDECTRL defaults.
>
> Signed-off-by: Alexander Kurz <akurz@blala.de>
Applied, thanks
Sascha
> ---
> arch/arm/boards/technexion-wandboard/lowlevel.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/arch/arm/boards/technexion-wandboard/lowlevel.c b/arch/arm/boards/technexion-wandboard/lowlevel.c
> index d3eb9a0..ff5ae6d 100644
> --- a/arch/arm/boards/technexion-wandboard/lowlevel.c
> +++ b/arch/arm/boards/technexion-wandboard/lowlevel.c
> @@ -276,7 +276,6 @@ static unsigned long wandboard_dram_init(void)
>
> __udelay(100);
>
> - mmdc_do_write_level_calibration();
> mmdc_do_dqs_calibration();
> #ifdef DEBUG
> mmdc_print_calibration_results();
> --
> 2.1.4
>
>
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prev parent reply other threads:[~2017-06-13 7:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-08 18:41 Alexander Kurz
2017-06-08 18:41 ` [PATCH 2/4] ARM: i.MX6 Wandboard Quad: fix PBL UART MUX Alexander Kurz
2017-06-08 18:55 ` Andrey Smirnov
2017-06-08 18:41 ` [PATCH 3/4] ARM: i.MX6 Wandboard: enable Wandboard Quad Alexander Kurz
2017-06-08 18:41 ` [PATCH 4/4] ARM: i.MX6 Wandboard: add Documentation Alexander Kurz
2017-06-13 7:27 ` Sascha Hauer [this message]
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