[U-Boot] [PATCH 10/18] arm: mx6: ddr: configure MMDC for slow_pd

[Tim Harvey <tharvey@gateworks.com>]

On Sun, Aug 3, 2014 at 12:34 AM, Nikita Kiryanov <nikita@compulab.co.il> wrote:
> According to MX6 TRM, both MMDC and DRAM should be configured to
> the same powerdown precharge. Currently, mx6_dram_cfg()
> configures MMDC for fast pd, and the DRAM for slow pd.

Nikita,

I'm inclined to agree with you. A glance at some of the existing
non-spl board config's show this same discrepancy which probably comes
form an error in the IMX DDR3 Script Aid spreadsheet
(https://community.freescale.com/docs/DOC-94917).

I would at least add to the description the fact that the precharge pd
is MR0 bit12 for DRAM and the current value of 0 indicates 'Slow exit
(DLL off)'. I've asked our Freescale FAE for clarification to see if
the spreadsheet is in error.

Regards,

Tim

>
> Configure MMDC for slow pd.
>
> Cc: Stefano Babic <sbabic@denx.de>
> Cc: Tim Harvey <tharvey@gateworks.com>
> Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
> ---
>  arch/arm/cpu/armv7/mx6/ddr.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm/cpu/armv7/mx6/ddr.c b/arch/arm/cpu/armv7/mx6/ddr.c
> index 70ce38f..c0fb749 100644
> --- a/arch/arm/cpu/armv7/mx6/ddr.c
> +++ b/arch/arm/cpu/armv7/mx6/ddr.c
> @@ -463,6 +463,7 @@ void mx6_dram_cfg(const struct mx6_ddr_sysinfo *sysinfo,
>         mmdc0->mdpdc = (tcke & 0x7) << 16 |
>                         5            << 12 |  /* PWDT_1: 256 cycles */
>                         5            <<  8 |  /* PWDT_0: 256 cycles */
> +                       1            <<  7 |  /* SLOW_PD */
>                         1            <<  6 |  /* BOTH_CS_PD */
>                         (tcksrx & 0x7) << 3 |
>                         (tcksre & 0x7);
> --
> 1.9.1
>