[U-Boot] [u-boot-release] [PATCH 1/2] powerpc/mpc8xxx: Fix DDR3 timing_cfg_1 and sdram_mode registers

Timur Tabi timur at freescale.com
Wed Mar 2 20:58:07 CET 2011


York Sun wrote:
> On Wed, 2011-03-02 at 13:46 -0600, Timur Tabi wrote:
>> York Sun wrote:
>>>>> if (wrrec_mclk & 1)
>>>>> 	wrrec_mclk++;
>>>>>
>>> Only 9, 11, 13, 15 need to round up.
>>
>> What are all the possible values for wrrec_mclk?
>>
> 
> There is no limitation on register timing_cfg_1[wrrec_mclk]. It can be
> any value. The limitation comes from JEDEC spec on mode register MR0.
> The write recovery for autoprecharge is within the values of 5, 6, 7, 8,
> 10, 12, 14, 16.

My point is that we can do something like this:

if (wrrec_mclk > 8 && wrrec_mclk < 16 && wrrec_mclk & 1)
	wrrec_mclk++;

But we can simplify this if I can know what all possible values are.

-- 
Timur Tabi
Linux kernel developer at Freescale



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