[U-Boot] [PATCH v2 00/11] SPL support for RISC-V

[Anup Patel]

On Fri, Aug 2, 2019 at 2:11 PM Rick Chen <rickchen36 at gmail.com> wrote:
>
> Hi Lukas
>
> >
> > Hi Rick,
> >
> > On Thu, 2019-08-01 at 11:32 +0800, Rick Chen wrote:
> > > Hi Lukas
> > >
> > > > > From: Lukas Auer [mailto:lukas.auer at aisec.fraunhofer.de]
> > > > > Sent: Sunday, July 28, 2019 11:57 PM
> > > > > To: u-boot at lists.denx.de
> > > > > Cc: Atish Patra; Rick Jian-Zhi Chen(陳建志); Bin Meng; Sagar Kadam; Alistair
> > > > > Francis; Anup Patel; Troy Benjegerdes; Lukas Auer; Abel Vesa; Alex Kiernan;
> > > > > Alex Marginean; Alexander Graf; Andreas Dannenberg; Andrew F. Davis; Anup
> > > > > Patel; Anup Patel; Atish Patra; Chris Packham; Eugeniu Rosca; Heiko Schocher;
> > > > > Heinrich Schuchardt; Jagan Teki; Jean-Jacques Hiblot; Jens Wiklander; Joe
> > > > > Hershberger; Kever Yang; Lokesh Vutla; Lukasz Majewski; Marek Vasut; Marek
> > > > > Vasut; Marek Vasut; Markus Klotzbuecher; Michal Simek; Paul Burton; Peng
> > > > > Fan; Philipp Tomsich; Philippe Reynes; Ryder Lee; Shawn Guo; Simon Glass;
> > > > > Simon Goldschmidt; Stefan Roese; Stefano Babic; Tien Fong Chee; Vignesh R;
> > > > > Weijie Gao; Ye Li
> > > > > Subject: [PATCH v2 00/11] SPL support for RISC-V
> > > > >
> > > > > This series adds support for SPL to RISC-V U-Boot. Images can be booted via
> > > > > OpenSBI (FW_DYNAMIC firmware) or by directly jumping to them. In the
> > > > > former case, OpenSBI and U-Boot proper are bundled as a FIT image and made
> > > > > available to U-Boot SPL. Currently, only the QEMU board enables U-Boot SPL
> > > > > with a dedicated configuration. It uses RAM as SPL boot device.
> > > > >
> > > > > On many RISC-V CPUs, the device tree is provided to U-Boot by the first stage
> > > > > bootloader. This requires changes to U-Boot SPL (patches 1,
> > > > > 2 and 3), which modify the behavior on other boards as well.
> > > > >
> > > > > To test this series, OpenSBI has to be compiled first. The fw_dynamic.bin
> > > > > binary must be copied into the U-Boot root directory.
> > > > > Alternatively, the location of the binary can be specified with the OPENSBI
> > > > > environment variable. U-Boot can then be build as normal using the
> > > > > configuration qemu-riscv64_spl_defconfig for 64-bit builds or
> > > > > qemu-riscv32_spl_defconfig for 32-bit builds. The outputs from the build
> > > > > process are the U-Boot SPL binary (spl/u-boot-spl.bin) and the U-Boot FIT
> > > > > image (u-boot.itb) containing U-Boot proper and OpenSBI.
> > > > >
> > > > > U-Boot can be run in QEMU with the following command.
> > > > >
> > > > > qemu-system-riscv64 -nographic -machine virt -kernel spl/u-boot-spl \
> > > > >       -device loader,file=u-boot.itb,addr=0x80200000
> > > > >
> > >
> > > Great job !
> > >
> >
> > Thank you!
> >
> > > I also try to run the spl flow on ax25-ae350 platform.
> > > But encounter some problems. I am still debugging.
> > >
> > > Following is the error message:
> > > :
> > > U-Boot SPL 2019.07-10574-ge6ef7ec-dirty (Aug 01 2019 - 10:09:45 +0800)
> > > Trying to boot from RAM
> > >
> > > U-Boot 2019.07-10574-ge6ef7ec-dirty (Aug 01 2019 - 10:09:45 +0800)
> > >
> > > DRAM:  exception code: 5 , Load access fault , epc 1212654 , ra 1200ffe
> > > ### ERROR ### Please RESET the board ###
> > >
> > > Do you have some comments ?
> > >
> >
> > It is difficult to judge without the exact configuration. Is your
> > current git tree available somewhere?
>
> No, it is not available yet.
> And you don't have the ax25-ae350 board, it is still in vain if the
> git tree is available.
>
> >
> > The error is quite strange, because it already booted U-Boot proper. So
> > the error does not happen in code, which has been directly modified by
> > this series. Perhaps it is trying to initialize something twice (once
> > in SPL and again in U-Boot proper)? Can you check at what location the
> > error occurs?
>
> I found that the exception occurred in get_ram_size() of ax25-ae350.c
> when it try to load the memory address 0x10000.
> But the access of 0x20000 is ok.
>
> I try to mark the get_ram_size() and do not execute it, U-Boot proper
> can boot successfully as below:
>
> U-Boot SPL 2019.07-10574-ge6ef7ec-dirty (Aug 02 2019 - 16:07:54 +0800)
> Trying to boot from RAM
>
> U-Boot 2019.07-10574-ge6ef7ec-dirty (Aug 02 2019 - 16:07:54 +0800)
> DRAM:  1 GiB
> Flash: 64 MiB
> MMC:   mmc at f0e00000: 0
> Loading Environment from SPI Flash... SF: Detected mx25u1635e with
> page size 256 Bytes, erase size 4 KiB, total 2 MiB
> *** Warning - bad CRC, using default environment
> In:    serial at f0300000
> Out:   serial at f0300000
> Err:   serial at f0300000
> Net:   no alias for ethernet0
> Warning: mac at e0100000 (eth0) using random MAC address - 36:13:4d:06:b8:fd
> eth0: mac at e0100000
> Hit any key to stop autoboot:  0
> RISC-V #
>
> So I tried to trace openSBI and found the BANNER of openSBI was not printed.
> Is it correct ?

Yes, U-Boot SPL is passing SBI_SCRATCH_NO_BOOT_PRINTS option to
OpenSBI due to which you don't see any prints. Although, error prints from
OpenSBI will be still available.

>
> Any idea about why the access of memory address(0x10000) will fail ?
> I guess it seem relative to pmp configuration.

If it is PMP access checks then you should get ACCESS faults error
prints from OpenSBI.

Regards,
Anup