[U-Boot] [PATCH] mx53loco: Fix boot hang during reboot stress test

[Stefano Babic <sbabic@denx.de>]

Hi Fabio,

On 09/02/2015 10:29, Fabio Estevam wrote:
> From: Fabio Estevam <fabio.estevam@freescale.com>
> 
> Currently by running the following test:
> 
> => setenv bootcmd reset
> => save
> => reset
> 
> , we observe a hang after approximately 20-30 minutes of stress reboot test.
> 
> Investigation of this issue revealed that when a single DDR chip select is used,
> the hang does not happen. It only happens when the two chip selects are active.
> 
> MX53 reference manual states at "28.6.2 Memory ZQ calibration sequence":
> 
> "The controller must keep the memory lines quiet (except for CK) for the ZQ
> calibration time as defined in the Jedec (512 cycles for ZQCL after reset, 256
> for other ZQCL and 64 for ZQCS)."
> 
> According to the SDE_0 and SDE_1 bit descriptions from register ESDCTL_ESDCTL:
> 
> "Writing 1 to SDE0 or SDE1 will initiate power up delays as JEDEC defines.
> Power up delays are a function of the configured memory type (DDR2/DDR3/LPDDR2)"
> 
> So make sure to activate one chip select at time (CS0 first and then CS1 later),
> so that the required JEDEC delay is respected for each chip select.
> 
> With this change applied the board has gone through three days of reboot stress
> test without any hang.
> 
> Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
> ---
>  board/freescale/mx53loco/imximage.cfg | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/board/freescale/mx53loco/imximage.cfg b/board/freescale/mx53loco/imximage.cfg
> index d1c1931..a5f1d98 100644
> --- a/board/freescale/mx53loco/imximage.cfg
> +++ b/board/freescale/mx53loco/imximage.cfg
> @@ -59,7 +59,7 @@ DATA 4 0x63fd9090 0x4d444c44
>  DATA 4 0x63fd907c 0x01370138
>  DATA 4 0x63fd9080 0x013b013c
>  DATA 4 0x63fd9018 0x00011740
> -DATA 4 0x63fd9000 0xc3190000
> +DATA 4 0x63fd9000 0x83190000
>  DATA 4 0x63fd900c 0x9f5152e3
>  DATA 4 0x63fd9010 0xb68e8a63
>  DATA 4 0x63fd9014 0x01ff00db
> @@ -72,6 +72,7 @@ DATA 4 0x63fd901c 0x00008033
>  DATA 4 0x63fd901c 0x00028031
>  DATA 4 0x63fd901c 0x052080b0
>  DATA 4 0x63fd901c 0x04008040
> +DATA 4 0x63fd9000 0xc3190000
>  DATA 4 0x63fd901c 0x0000803a
>  DATA 4 0x63fd901c 0x0000803b
>  DATA 4 0x63fd901c 0x00028039
> 

Good catch !

Acked-by: Stefano Babic <sbabic@denx.de>

Best regards,
Stefano Babic

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