[U-Boot] [PATCH v2 2/3] mx23: Enable tRAS lockout (24 bit of HW_DRAM_CTL08) as in imx-bootlets

[Otavio Salvador]

On Tue, Jan 29, 2013 at 12:33 AM, Marek Vasut <marek.vasut at gmail.com> wrote:
> Dear Otavio Salvador,
>
>> This enables the 'Fast Auto Pre-Charge' found in the memory chip.
>>
>> Signed-off-by: Otavio Salvador <otavio at ossystems.com.br>
>> ---
>> Changes in v2:
>> - Improve commit message
>>
>>  arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c
>> b/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c index 836e636..a9efd87 100644
>> --- a/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c
>> +++ b/arch/arm/cpu/arm926ejs/mxs/spl_mem_init.c
>> @@ -90,7 +90,7 @@ static uint32_t dram_vals[] = {
>>  #elif defined(CONFIG_MX23)
>>       0x01010001, 0x00010100, 0x01000101, 0x00000001,
>>       0x00000101, 0x00000000, 0x00010000, 0x01000001,
>> -     0x00000000, 0x00000001, 0x07000200, 0x00070202,
>> +     0x01000000, 0x00000001, 0x07000200, 0x00070202,
>>       0x02020000, 0x04040a01, 0x00000201, 0x02040000,
>>       0x02000000, 0x19000f08, 0x0d0d0000, 0x02021313,
>>       0x02061521, 0x0000000a, 0x00080008, 0x00200020,
>
> I went through the u-boot mem init and detected you apparently added the
> following undocumented portion of code (the writel((1 << 24 ...) already:
>
> 112 static void initialize_dram_values(void)
> 113 {
> 114         int i;
> 115
> 116         mxs_adjust_memory_params(dram_vals);
> 117
> 118         for (i = 0; i < ARRAY_SIZE(dram_vals); i++)
> 119                 writel(dram_vals[i], MXS_DRAM_BASE + (4 * i));
> 120
> 121 #ifdef CONFIG_MX23
> 122         writel((1 << 24), MXS_DRAM_BASE + (4 * 8));
> 123 #endif
> 124 }
>
> It does enable the TRANS_LOCKOUT. So what the heck is going on here? Are you
> coding this stuff at random now ? WHAT THE FUCK IS HAPPENING HERE ?!

What your tone, please.

Indeed, it does it. It has been done loooong time ago when we started
looking at MX23 and it was not obvious for me it.

I will send a patch reverting it and adding a comment explaning it
there so it is documented.

--
Otavio Salvador                             O.S. Systems
E-mail: otavio at ossystems.com.br  http://www.ossystems.com.br
Mobile: +55 53 9981-7854              http://projetos.ossystems.com.br