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

Otavio Salvador
2013-01-29T10:10:42Z

On Tue, Jan 29, 2013 at 12:33 AM, Marek Vasut <marek.vasut@gmail.com> wrote:
> Dear Otavio Salvador,
>
>> This enables the 'Fast Auto Pre-Charge' found in the memory chip.
>>
>> Signed-off-by: Otavio Salvador <otavio@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