[U-Boot] [PATCH v8 2/3] Odroid-XU3: Add support for Odroid-XU3

[Przemyslaw Marczak <p.marczak@samsung.com>]

Hello Hyungwon,

On 11/18/2014 12:44 PM, Przemyslaw Marczak wrote:
> Hello,
>
> On 11/18/2014 02:57 AM, Hyungwon Hwang wrote:
>> Dear Przemyslaw Marczak,
>>
>>>> +/*
>>>> + * FIXME: The number of bank is actually 8. But there is no way to
>>>> reserver the
>>>> + * last 16 Mib in the last bank now. So I just excluded the last
>>>> bank
>>>> + * temporally.
>>>> + */
>>>
>>> It's not prober solution, since non-dt kernel could get wrong DRAM
>>> size. Please look at board/samsung/odroid/odroid.c - into function
>>> exynos_init().
>>>
>>> The Odroid U3 has reserved the last 1MB of the last DRAM bank.
>>
>> I agree. It is a temporary solution, and it must be fixed soon. I see
>> the exynos_init() function and adapt the method to fix the problem in
>> Odroid XU3. But it did not work. Figuring out what is wrong, I found
>> that the 2 lines of code in the exynos_init() to reserve the last 1MB
>> does not affect the behavior of Odroid U3. Even after I commented out
>> the codes, it works well. Is it a effective solution to reserve the
>> memory? Is there anything else which I am missing?
>>
>> I really appreciate for your comment. Thanks.
>>
>> Best regards,
>> Hyungwon Hwang.
>>
>
> Yes, I also checked now, that this doesn't work for your board.
>
> On Odroid U3, there was a problem in the kernel - so dram size passed to
> the kernel is decreased by 1MB. It don't make a difference for the
> U-Boot if you don't touch this memory.
>
> I can suppose that it depends on secure firmware.
>
> If you plan to fix it in the future, then it's ok. In other way it will
> require some modification of board/samsung/common/board.c dram code.
>
> You can leave it as it is, since I plan to send some patches from
> tizen.org for exynos ram init.
> And it probably will fix this issue - if dts has decreased last bank
> size with the 16MiB.
>
> Best regards,

I made some quick test:
(diff)
         for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
                 addr = CONFIG_SYS_SDRAM_BASE + (i * SDRAM_BANK_SIZE);
-               gd->ram_size += get_ram_size((long *)addr, SDRAM_BANK_SIZE);
+               if (i == 7)
+                       gd->ram_size += (SDRAM_BANK_SIZE - (22 << 20));
+               else
+                       gd->ram_size += SDRAM_BANK_SIZE;
         }
         return 0;

Similar in dram_init_banksize():
-               size = get_ram_size((long *)addr, SDRAM_BANK_SIZE);
+
+               if (i == 7)
+                       size = (SDRAM_BANK_SIZE - (22 << 20));
+               else
+                       size = SDRAM_BANK_SIZE;

and this works fine.
I also checked that size of the reserved area is 22MiB.

Best regards,
-- 
Przemyslaw Marczak
Samsung R&D Institute Poland
Samsung Electronics
p.marczak@samsung.com