[U-Boot] SAMA5D2 xplained SD/eMMC boot

[Marek Vasut]

On 04/22/2016 02:54 AM, Yang, Wenyou wrote:
> Hi Marek,

Hi!

>> -----Original Message-----
>> From: Marek Vasut [mailto:marex at denx.de]
>> Sent: 2016年4月21日 10:59
>> To: Yang, Wenyou <Wenyou.Yang at atmel.com>
>> Cc: u-boot at lists.denx.de
>> Subject: Re: SAMA5D2 xplained SD/eMMC boot
>>
>> On 04/21/2016 04:46 AM, Yang, Wenyou wrote:
>>> Hi,
>>
>> Hi!
>>
>> [...]
>> pile of unnecessary email headers redacted.
>> [...]
>>
>>>>>>>>>> Hi!
>>>>>>>>>>
>>>>>>>>>> I've been playing around with latest mainline u-boot on sama5d2
>>>>>>>>>> xplained ultra. I noticed that if I want to boot the board from
>>>>>>>>>> SD card (SDHCI1), the board will indeed load the SPL from it,
>>>>>>>>>> but SPL will try to load u-boot.img from eMMC
>>>>>>>>>> (SDHCI0) and fail, as my eMMC is blank.
>>>>>>>>>
>>>>>>>>> Yes, there is some issue to load u-boot.img. I found there is
>>>>>>>>> something to do on
>>>>>>>> sdhci.c.
>>>>>>>>>
>>>>>>>>> You can try this branch, it should works.
>>>>>>>>>
>>>>>>>>> https://github.com/linux4sam/u-boot-at91/commits/u-boot-2016.03-
>>>>>>>>> at
>>>>>>>>> 91
>>>>>>>>
>>>>>>>> I am not interested in using non-mainline stuff. Do you have any
>>>>>>>> particular patch/commit which I can refer to ? I do not think
>>>>>>>> this has anything to do with sdhci.c driver at all, it has to do
>>>>>>>> with detecting the boot device from which SPL was started and
>>>>>>>> loading u-boot.img from the same boot device instead of always using
>> SDHCI0.
>>>>>>>
>>>>>>> I will test the mainline code. I will let you know when I get something.
>>>>>>
>>>>>> OK.
>>>>>>
>>>>>> Does the SoC have any sort of register which lists the current boot device ?
>>>>>
>>>>> In this SoC, there is not register to list the current boot device.
>>>>
>>>> And thus, it is not possible to detect at runtime from which device
>>>> the SoC booted and thus load u-boot.img from the same device. Correct ?
>>>
>>> Yes,
>>
>> Ha, thanks for confirming.
> 
> Sorry, can I correct what I said yesterday?

What if I said "no" ? :-)

> There is a register to list the boot information exported by ROMCode.
> 
> The boot information is stored in R4 register when the ROMCode jumps to the bootstrap. 

Ha, so the U-Boot SPL can save the r4 register early in the boot and
extract the boot device from it. That's neat. Thanks!

> Here is the contents definitions R4 on the SAMA5D2 (improved compared to old MPUs to take care of IOSet features).

Is this stuff somewhere in the SAMA5Dx datasheet ? It'd be nice to
know/have this information for other SAMA5Dx too (d3 and d4).

> /* bootFrom ID Definitions */
> #define BOOT_FROM_KEY             	(0xBAu << 24)
> 
> #define BOOT_FROM_SPI               	(0x0u << 0)
> #define BOOT_FROM_MCI               	(0x1u << 0)
> #define BOOT_FROM_SMC               	(0x2u << 0)
> #define BOOT_FROM_TWI               	(0x3u << 0)
> #define BOOT_FROM_QSPI             	(0x4u << 0)
> 
> /* ID number of the IP from the data sheet */
> #define BOOT_FROM_ID0               (0x0u << 4)
> #define BOOT_FROM_ID1               (0x1u << 4)
> #define BOOT_FROM_ID2               (0x2u << 4)
> #define BOOT_FROM_ID3               (0x3u << 4)
> #define BOOT_FROM_ID4               (0x4u << 4)
> 
> #define BOOT_FROM_ID_Pos            	4
> #define BOOT_FROM_ID_Msk            	(0xfu << BOOT_FROM_ID_Pos)
> #define BOOT_FROM_ID(value)         	((BOOT_FROM_ID_Msk & ((value) << BOOT_FROM_ID_Pos)))
> 
> #define BOOT_FROM_TYPE_SD_OR_AT25   	(0x0u << 8)
> #define BOOT_FROM_TYPE_MMC_OR_AT45  (0x1u << 8)
> #define BOOT_FROM_TYPE_EMMC         	(0x2u << 8)
> 
> /* QSPI serial flashes */
> #define BOOT_FROM_TYPE_SPANSION     	(0x0u << 8)
> #define BOOT_FROM_TYPE_MICRON       	(0x1u << 8)
> #define BOOT_FROM_TYPE_MACRONIX     	(0x2u << 8)
> 
> /* Chip Select or (MCI) Slot identifier used in code by the IP. */
> #define BOOT_FROM_CS0               (0x0u << 12) // Slot A
> #define BOOT_FROM_CS1               (0x1u << 12) // Slot B
> #define BOOT_FROM_CS2               (0x2u << 12) // Slot C
> #define BOOT_FROM_CS3               (0x3u << 12) // Slot D
> #define BOOT_FROM_CS4               (0x4u << 12)
> 
> #define BOOT_FROM_CS_Pos            12
> #define BOOT_FROM_CS_Msk            (0xfu << BOOT_FROM_CS_Pos)
> #define BOOT_FROM_CS(value)         ((BOOT_FROM_CS_Msk & ((value) << BOOT_FROM_CS_Pos)))
> 
> #define BOOT_FROM_IOSET_Pos         16
> #define BOOT_FROM_IOSET_Msk         (0x3u << BOOT_FROM_IOSET_Pos)
> #define BOOT_FROM_IOSET(value)       ((BOOT_FROM_IOSET_Msk & ((value) << BOOT_FROM_IOSET_Pos)))>>
> 
> 
>> [...]
>>
>> --
>> Best regards,
>> Marek Vasut
> 
> Sorry for incorrect information before.

No problem, thanks for the update!

> Best Regards,
> Wenyou Yang
> 


-- 
Best regards,
Marek Vasut