Re: [PATCH] arm: imx: mmdc_size: Increase row_max for imx8m

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 20.06.22 14:47, Teresa Remmet wrote:
> Am Montag, dem 20.06.2022 um 14:38 +0200 schrieb Ahmad Fatoum:
>> On 20.06.22 14:27, Teresa Remmet wrote:
>>> I have set the DDRC_ADDRMAP7 register manually in the RAM
>>> configuration
>>> in such a case. As I don't see a solution that fits for all. But
>>> would
>>> be happy for one. :)
>>
>> What would the 'neutral' value to write into this register be? zero
>> seems to not be it.
> 
> it's 
> 
> 0xf0f for ADDRMAP7.
> 
> Reference Manual says: "If set to 15, row address bit X is set to 0"

Do newer spreadsheets always generate ADDRMAP7 writes even if the
value is zero? If so, we could perhaps initialize it to 0xf0f before
running ddr_cfg_umctl2(). The DDRC seems to be in reset while the
registers are being written, so this might just work.

As 0 is a valid value, I am wondering if this snippet introduced with
42d45ef380c5 ("ARM: imx: Add imx8 support for SDRAM with two or more bank groups")
is correct:

if (addrmap[8]) {
        if (FIELD_GET(DDRC_ADDRMAP8_BG_B0, addrmap[8]) != 0b11111)
                banks++;
        if (FIELD_GET(DDRC_ADDRMAP8_BG_B1, addrmap[8]) != 0b111111)
                banks++;
}

Thanks,
Ahmad

> 
> Regards,
> Teresa
> 
> 
>>
>> Thanks,
>> Ahmad
>>
>>> Regards,
>>> Teresa
>>>
>>>>> ---
>>>>>  arch/arm/mach-imx/esdctl.c | 2 +-
>>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-
>>>>> imx/esdctl.c
>>>>> index 8dd0ddbbc965..b070ebc62a45 100644
>>>>> --- a/arch/arm/mach-imx/esdctl.c
>>>>> +++ b/arch/arm/mach-imx/esdctl.c
>>>>> @@ -488,7 +488,7 @@ static resource_size_t
>>>>> imx8m_ddrc_sdram_size(void __iomem *ddrc)
>>>>>  
>>>>>  	return imx_ddrc_sdram_size(ddrc, addrmap,
>>>>>  				   12, ARRAY_AND_SIZE(col_b),
>>>>> -				   16, ARRAY_AND_SIZE(row_b),
>>>>> +				   18, ARRAY_AND_SIZE(row_b),
>>>>>  				   reduced_adress_space, true);
>>>>>  }
>>>>>  
>>
>>


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