[PATCH v5 0/3] Add riscv semihosting support in u-boot

[Kautuk Consul]

Sorry about that! I assumed everyone would know the option and decided to
just upt the ordinary command
to show that the semihosting changes don't impact the non-semihosting
scenarios.

On Sat, Dec 3, 2022 at 11:32 AM Bin Meng <bmeng.cn at gmail.com> wrote:

> Hi Kautuk,
>
> On Sat, Dec 3, 2022 at 12:28 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> >
> > On Tue, Nov 29, 2022 at 2:58 PM Kautuk Consul <kconsul at ventanamicro.com>
> wrote:
> > >
> > > I have tested it both on Qemu and Ventana's internal simulator.
> >
> > How to verify this? I used your instructions and U-Boot says: No match
> > for driver 'serial_semihosting'
> >
> > U-Boot 2023.01-rc2-00113-g2a4accaf5e (Dec 03 2022 - 12:20:20 +0800)
> > CPU: rv64imafdch_zicsr_zifencei_zihintpause_zba_zbb_zbc_zbs_sstc
> > Model: riscv-virtio,qemu
> > DRAM: 256 MiB
> > No match for driver 'serial_semihosting'
> > Some drivers were not found
> > Core: 25 devices, 12 uclasses, devicetree: board
> > Flash: 32 MiB
> > Loading Environment from nowhere... OK
> > In: serial at 10000000
> > Out: serial at 10000000
> > Err: serial at 10000000
> > Net: No ethernet found.
> > Working FDT set to 8f734950
> > Hit any key to stop autoboot: 0
> > =>
> >
> > >
> > > On Tue, Nov 29, 2022 at 12:06 PM Bin Meng <bmeng.cn at gmail.com> wrote:
> > >>
> > >> Hi Kautuk,
> > >>
> > >> On Tue, Nov 29, 2022 at 2:29 PM Kautuk Consul <
> kconsul at ventanamicro.com> wrote:
> > >> >
> > >> > Hi,
> > >> >
> > >> > Can someone pick this patchset up ?
> > >> >
> > >> > It has been reviewed and there has been no comment on this in
> recent days.
> > >> >
> > >> > Thanks.
> > >> >
> > >> > On Fri, Sep 23, 2022 at 12:33 PM Kautuk Consul <
> kconsul at ventanamicro.com> wrote:
> > >> >>
> > >> >> Semihosting is a mechanism that enables code running on
> > >> >> a target to communicate and use the Input/Output
> > >> >> facilities on a host computer that is running a debugger.
> > >> >> This patchset adds support for semihosting in u-boot
> > >> >> for RISCV64 targets.
> > >> >>
> > >> >> CHANGES since v4:
> > >> >> -       Check arch dependencies for SEMIHOSTING as well as
> SPL_SEMIHOSTING
> > >> >>         config options as per Sean's comment.
> > >> >> -       arch/riscv/lib/interrupts.c: Check for post and pre
> instructions
> > >> >>         of the ebreak statement whether they are as per the RISCV
> > >> >>         semihosting specification. Only then do a
> disable_semihosting
> > >> >>         and epc += 4 and return.
> > >> >>
> > >> >> Compilation and test commands for SPL and S-mode configurations
> > >> >> =================================================================
> > >> >>
> > >> >> U-Boot S-mode on QEMU virt
> > >> >> ----------------------------
> > >> >> // Compilation of S-mode u-boot
> > >> >> ARCH=riscv
> > >> >> CROSS_COMPILE=riscv64-unknown-linux-gnu-
> > >> >> make qemu-riscv64_smode_defconfig
> > >> >> make
> > >> >> // Run riscv 64-bit u-boot with opensbi on qemu
> > >> >> qemu-system-riscv64 -M virt -m 256M -display none -serial stdio
> -bios\
> > >> >> opensbi/build/platform/generic/firmware/fw_jump.bin -kernel\
> > >> >> u-boot/u-boot.bin
>
> It turns out your instructions missed "-semihosting" in the QEMU command
> line.
>
> With that I can see U-Boot boots with the serial_semihosting driver.
>
> > >> >>
> > >> >> U-Boot SPL on QEMU virt
> > >> >> ------------------------
> > >> >> // Compilation of u-boot-spl
> > >> >> ARCH=riscv
> > >> >> CROSS_COMPILE=riscv64-unknown-linux-gnu-
> > >> >> make qemu-riscv64_spl_defconfig
> > >> >> make OPENSBI=opensbi/build/platform/generic/firmware/fw_dynamic.bin
> > >> >> // Run 64-bit u-boot-spl in qemu
> > >> >> qemu-system-riscv64 -M virt -m 256M -display none -serial stdio
> -bios\
> > >> >> u-boot/spl/u-boot-spl.bin -device\
> > >> >> loader,file=u-boot/u-boot.itb,addr=0x80200000
> > >> >>
> > >>
> > >> Do you have instructions on how to actually test semihosting? Does it
> > >> require a JTAG debugger? But I see you are using QEMU?
> > >>
> >
>
> Regards,
> Bin
>