[U-Boot] Proposal to add NAND-boot support for Sunxi SPL

[Alexander Kaplan]

Hi,

I tried both the kernel from
https://github.com/jwrdegoede/linux-sunxi/commits/sunxi-nand-experiment

and u-boot from
https://gitlab.com/turtle-solutions/u-boot/commits/sunxi-nand-wip

I can successfully compile and boot them on my A13-OLinuXino but there is
no NAND available. Neither in kernel log nor in the u-boot output there is
anything mentioned about NAND. I tried to enable all the NAND options,
especially the "Support for NAND on Allwinner SoCs" in nconfig but I'm
afraid I still have not found the right configuration.

Would it be possible to share the build configuration files?

Thanks in advance
Alex

On Tue, May 26, 2015 at 7:52 AM, Hans de Goede <hdegoede at redhat.com> wrote:

> Hi,
>
>
> On 05/26/2015 09:34 AM, Roy Spliet wrote:
>
>> Hello Hans,
>>
>> Re-sent to everybody instead of just you. Reply inline.
>>
>> Op 25-05-15 om 22:39 schreef Hans de Goede:
>>
>>> Hi,
>>>
>>> On 25-05-15 20:35, Hans de Goede wrote:
>>>
>>>> Hi,
>>>>
>>>> On 22-05-15 09:04, Roy Spliet wrote:
>>>>
>>>>> Hello,
>>>>>
>>>>> For my set-up I made use of Boris Brezillon's sunxi-nand tree[1], or
>>>>> actually I rebased his patches on top of 4.0rc7. This basically adds
>>>>> support for NAND-chip partitioning, ECC and randomisation. Docs for the DT
>>>>> specification in Documentation/devicetree/bindings/mtd/sunxi-nand.txt , and
>>>>> an example can be found in arch/arm/boot/dts/sun7i-a20-cubietruck.dts . [2]
>>>>> lists the acceptable configuration options for the boot and boot_rescue
>>>>> partitions, make sure to pick one of these (which should be no problem for
>>>>> MLC-type nand). The ECC mode for these boot partitions is called
>>>>> hw_syndrome.
>>>>>
>>>>> Assuming you now have a Linux set-up kernel based on this tree with
>>>>> NAND support on an MMC, for U-boot what you should currently do is:
>>>>> 1) in include/configs/sunxi-common.h, adjust the parameters
>>>>> <CONFIG_NAND_SUNXI_>PAGE_SIZE, ECC_STEP, ECC_STRENGTH to match your NAND
>>>>> chip and DT configuration.
>>>>> 2) Build
>>>>> 3) Use your MMC to flash u-boot-sunxi-with-spl.bin onto NAND:
>>>>> # flash_erase /dev/mtd0
>>>>> # nandwrite -p /dev/mtd0 u-boot-sunxi-with-spl.bin
>>>>> 4) Reboot without the MMC card and see U-boot load
>>>>>
>>>>
>>>> Ok, it took me way longer then I wanted (see below) but I've this
>>>> working now. It is cool to see u-boot load from nand :)
>>>>
>>>>>
>>>>> That should be all.
>>>>>
>>>>> @Alex: To answer your question specifically: It's likely that the
>>>>> parameters in sunxi-common.h mentioned above might not match your NAND-chip
>>>>> configuration in the Linux kernel. I can't tell you precisely how to fetch
>>>>> these details from the 3.4 kernel, sorry. I recall Daniel using 24-bit
>>>>> strength ECC with otherwise equal parameters, but perhaps he can help you
>>>>> with this better than I can.
>>>>>
>>>>
>>>> Alex, could it be that you are writing the nand using
>>>> a (rebased) version of bbrezillon's sunxi-nand-next branch ?
>>>>
>>>> I started with that too because it is much newer and contains
>>>> various bug fixes, but it seems that it also contains a new
>>>> bug causing it to write the NAND in such a way that the BROM
>>>> and u-boot SPL code will not read it.
>>>>
>>>> I've just pushed a rebased version of the sunxi-nand branch of
>>>> Boris here:
>>>>
>>>> https://github.com/jwrdegoede/linux-sunxi/commits/sunxi-nand-experiment
>>>>
>>>> And that works for me, where as before I got the exact same errors
>>>> trying to fel load a nand enabled spl.
>>>>
>>>> I'm working on merging over all the changes from the sunxi-nand-next
>>>> branch onto my working sunxi-nand-experiment branch 1 by 1 until
>>>> I find the one which causes the breakage...
>>>>
>>>
>>> Ok, so quick update the breakage was caused by this commit:
>>>
>>>
>>> https://github.com/bbrezillon/linux-sunxi/commit/7f7324bc6170a45742352070fb45170779a3611c
>>>
>>> When it was rebased someone (Boris I guess) forgot to remove the
>>> "chip->read_buf(mtd, NULL, ecc->size);" line at line 1075 (after the
>>> patch) and
>>> likewise the "chip->write_buf(mtd, buf + (i * ecc->size), ecc->size);"
>>> line at
>>> line 1161. With these 2 lines removed the sunxi-nand-next branch from
>>> Boris,
>>> rebased on 4.1-rc1 can write the nand boot parts and the brom / spl can
>>> load
>>> the spl / resp. u-boot.bin from there (on a cubieboard2).
>>>
>> You're right... I did spot this, but assumed this was my own mistake in
>> merging these patches with our 4.0RC7 tree. Sorry, could have saved you
>> some trouble if I were sharper.
>>
>>>
>>> I've also tried to get this code running on a cubieboard (non 2 so A10
>>> rather then
>>> A20), the SPL loads fine there (indicating that the kernel bits work),
>>> but then
>>> I get:
>>>
>>> U-Boot SPL 2015.07-rc1-00287-g050de86-dirty (May 25 2015 - 22:28:19)
>>> DRAM: 1024 MiB
>>> CPU: 1008000000Hz, AXI/AHB/APB: 3/2/2
>>> Nand initialised
>>> NAND timeout reading data
>>> NAND timeout reading data
>>> NAND timeout reading data
>>> NAND timeout reading data
>>> NAND timeout reading data
>>> NAND timeout reading data
>>> ...
>>>
>> Thanks for testing this. I don't own an A10 myself, so I haven't observed
>> this behaviour.
>> First thing I would verify personally is whether all the clocks are
>> properly configured. Could you make U-boot print &ccm->ahb_gate0 and
>> &ccm->nand0_clk_cfg? For the first, bits 6 (DMA) and 13 (NAND) must be set,
>> the second must have bit 31 set, bits 24 and 25 cleared (and otherwise, the
>> accompanying PLL must be configured too... probably easier to use the
>> OSC24M), and the divide ratios set to 0 (although a small divider, like 1,
>> shouldn't be a problem either).
>> I am assuming these values should be correct, but only because BROM
>> initialised part of it. I am aware of the fact that the SPL driver doesn't
>> control the DMA gating reg and the NAND post-dividers. It might be a good
>> idea to do so for as long as we don't have a full DMA driver, so I'll patch
>> that up today.
>>
>
> I've just tried the prelimary v4 of your patch-set from:
> https://gitlab.com/turtle-solutions/u-boot/commits/sunxi-nand-wip
>
> And the changes you've made fix these errors on the A10, good job.
>
> Regards,
>
> Hans
>