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

["Daniel Kochmański" <jackdaniel@hellsgate.pl>]

Hello Alexander,

you have to put correct nand configuration in devicetree in
arch/arm/boot/dts/sun5i-a13-olinuxino.dts of your board. For comparision
you may check sun7i-a20-cubieboard2.dts which has appropriate
definitions. sunxi-nand-wip branch works on a20.

Good luck!
Daniel

Alexander Kaplan writes:

> 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@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
>>

-- 
Daniel Kochma?ski | Pozna?, Poland
;; aka jackdaniel

"Be the change that you wish to see in the world." - Mahatma Gandhi