On 04/26/2016 03:47 AM, Yang, Wenyou wrote:
-----Original Message----- From: Marek Vasut [mailto:marex@denx.de] Sent: 2016年4月25日 18:30 To: Yang, Wenyou Wenyou.Yang@atmel.com Cc: u-boot@lists.denx.de Subject: Re: SAMA5D2 xplained SD/eMMC boot
On 04/25/2016 02:55 AM, Yang, Wenyou wrote:
Hi Marek,
-----Original Message----- From: Marek Vasut [mailto:marex@denx.de] Sent: 2016年4月22日 20:18 To: Yang, Wenyou Wenyou.Yang@atmel.com Cc: u-boot@lists.denx.de Subject: Re: SAMA5D2 xplained SD/eMMC boot
On 04/22/2016 02:54 AM, Yang, Wenyou wrote:
Hi Marek,
Hi!
-----Original Message----- From: Marek Vasut [mailto:marex@denx.de] Sent: 2016年4月21日 10:59 To: Yang, Wenyou Wenyou.Yang@atmel.com Cc: u-boot@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 >>>>>>> .0 >>>>>>> 3- >>>>>>> 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).
It seems it is not included in the in the SAMA5Dx datasheet.
So where did you get these numbers from ?
Yes, it is not included in the datasheet now. We are not recommend to use them.
If it is helpful for you, please reference the previous mail.
It is helpful, I sent a patch for SAMA5D2 which makes it behave sane. I will have to battle SAMA5D4 board soon, so I will most likely extend that patch for SAMA5D4.
This feature is available since AT91SAM9G45, inclusive d3 and d4.
Oh cool, so the numbers are the same for all these chips ?
Yes, basically same, only d2 includes additional ioset information.
OK, the IOSET is not interesting for now.
It'd be cool to have this documented somewhere :)
Best regards, Marek Vasut