[PATCH v5 11/11] riscv: Add FPIOA and GPIO support for Kendryte K210

[Ruinland ChuanTzu Tsai <ruinland@andestech.com>]

Hi Sean and all,

Sorry for dropping this mail out of the blue.

I'm trying to follow the instrcutions from `doc/board/sipeed/maix.rst`
to build and flash u-boot so as to verify Sean's work on `maix_gpio_good` tree.

Yet the console has no output.

Furthermore, I found the documentation on Sipeed board to be a little bit confusing.
In your first commit of that document, it's stated that "only the Sipeed MAIX BiT
V2.0 (bitm) and Sipeed MAIXDUINO are supported."
Yet the later commit (137dc15) added a table which implies that the older version
of MAIX BiT is supported. So I'm a bit confused about whether older MAIX BiTs get
supported or not ? (I'm testing the builts on the older version.)
Does the replacement of CH34x with CH552 may cause the issue I'm encountering ?

By the way, I was trying to use the pre-built toolchain from kendryte's GitHub [1].
Yet the linker (riscv64-unknown-elf-ld.bfd) complains that `-pie` is not supported.
Hence I switched to the the binutils v2.34 built from upstream and the u-boot could
be built without that hiccup.

Could someone tell me which toolchain is recommended for building the u-boot for
boards Kendryte K210 ?

[1] https://github.com/kendryte/kendryte-gnu-toolchainhttps://github.com/kendryte/kendryte-gnu-toolchain

Many thanks,
Ruinland

On Thu, Aug 20, 2020 at 02:25:36PM +0800, Rick Jian-Zhi Chen(???) wrote:
> 
> 
> -----Original Message-----
> From: Sean Anderson [mailto:seanga2 at gmail.com] 
> Sent: Wednesday, August 19, 2020 7:13 PM
> To: Rick Chen
> Cc: U-Boot Mailing List; Simon Glass; Tom Rini; Bin Meng; Rick Jian-Zhi Chen(???); Alan Quey-Liang Kao(???)
> Subject: Re: [PATCH v5 11/11] riscv: Add FPIOA and GPIO support for Kendryte K210
> 
> On 8/18/20 11:48 PM, Rick Chen wrote:
> > Hi Tom
> > 
> >> This patch adds the necessary configs and docs for FPIOA and GPIO support
> >> on the K210.
> >>
> >> The board does not boot unless CONSOLE_LOGLEVEL is set to a non-default
> >> value . It also boots when the tree is dirty (and CONSOLE_LOGLEVEL is not
> >> changed). It also boots when changes are made to the device tree and then
> >> committed. I don't know why this happens. These breakages only occur after
> >> bf2fb81ad3.
> >>
> >> Signed-off-by: Sean Anderson <seanga2@gmail.com>
> >> ---
> >>
> >> Changes in v5:
> >> - Increase CONSOLE_LOGLEVEL to 5 as a hack to get the board booting again
> >> - Patch 05/12 "gpio: sifive: Use generic reg read function" has been superseded
> >>   by commit 2548493ab4.
> > 
> > Would you like to pick up this series, [PATCH v5 00/11] riscv: Add
> > FPIOA and GPIO support for Kendryte K210 ?
> > Or maybe it is better to figure out what is wrong here and find the
> > root cause why it need to Increase CONSOLE_LOGLEVEL to 5 as a hack ?
> 
> As an additional note, *CONFIG_LOGLEVEL (whoops) can also be decreased
> for the same effect. In addition, there are several other ways I found
> to "fix" this bug (as noted in the commit message). If you would like to
> test this out, I have two trees [1, 2] where this series (actually a slightly
> earlier version of this series) is applied just before and just after
> bf2fb81ad3. The original patch is located at [3].
> 
> --Sean
> 
> [1] https://github.com/Forty-Bot/u-boot/tree/maix_gpio_good
> [2] https://github.com/Forty-Bot/u-boot/tree/maix_gpio_bad
> [3] https://patchwork.ozlabs.org/project/uboot/patch/20200724111225.12513-15-ovidiu.panait at windriver.com/