On Wed, 2018-09-05 at 09:28 +0800, Rick Chen wrote: > > > From: Auer, Lukas [mailto:lukas.a...@aisec.fraunhofer.de] > > > Sent: Wednesday, September 05, 2018 5:53 AM > > > To: bmeng...@gmail.com > > > Cc: Rick Jian-Zhi Chen(陳建志); u-boot@lists.denx.de > > > Subject: Re: [U-Boot] [PATCH 12/12] riscv: Add QEMU virt board > support > > > > > > On Tue, 2018-09-04 at 17:31 +0800, Bin Meng wrote: > > > > Hi Lukas, > > > > > > > > On Tue, Sep 4, 2018 at 5:39 AM Auer, Lukas > > > > <lukas.a...@aisec.fraunhofer.de> wrote: > > > > > > > > > > On Thu, 2018-08-30 at 00:54 -0700, Bin Meng wrote: > > > > > > This adds QEMU RISC-V 'virt' board target support, with > the hope > > > > > > of helping people easily test U-Boot on RISC-V. > > > > > > > > > > > > The QEMU virt machine models a generic RISC-V virtual > machine > > > > > > with support for the VirtIO standard networking and block > > > > > > storage devices. > > > > > > It has CLINT, PLIC, 16550A UART devices in addition to > VirtIO > > > > > > and it also uses device-tree to pass configuration > information > > > > > > to guest software. It implements RISC-V privileged > architecture > > > > > > spec v1.10. > > > > > > > > > > > > Both 32-bit and 64-bit builds are supported. Support is > pretty > > > > > > much preliminary, only booting to U-Boot shell with the > UART > > > > > > driver on a single core. Booting Linux is not supported > yet. > > > > > > > > > > > > > > > > For your information and to avoid duplicate work, I am > working on > > > > > a patch set that improves RISC-V support in u-boot. I am > currently > > > > > able to boot Linux on a multi-core setup in QEMU, but they > are not > > > > > quite ready to submit yet. > > > > > > > > > > > > > This is great! My next step is to work on virtio driver > support in > > > > U-Boot as qemu-riscv virt machine has these devices but we > don't > > > > have corresponding drivers in U-Boot. Then I will try to boot > Linux > > > > after that. Good to hear you already boot Linux with qemu- > riscv! > > > > Have you already supported virtio drivers in your port? If > yes, I > > > > will just hold on and wait for your patch series :-) > > > > > > > > > > Hi Bin, > > > > > > Support for the virtio devices would be great! I don't support > them in > > > my port, I can only boot a kernel image from RAM. > > > I only have a driver for the clint0 (core local interrupt > controller), > > > which I need for software interrupts to other cores and as a > timer. > > > Software interrupts also work over the supervisor binary > interface > > > (SBI), which allows u-boot to run in supervisor mode with bbl > running > > > in machine mode to handle the SBI calls. > > > > > Hi Bin and Auer > > I have already boot bbl run in S-mode and riscv-linux in M-mode via > u-boot from SD card or FLASH. > It mean after booting riscv-linux, u-boot will be dead. And no matter > about kernel. > Please refer to doc/README.ae350 > > May I figure out more clearly what are you going to do ? > What are you going to do is let u-boot run in S-mode and boot bbl and > riscv-linux in M-mode, right ? > It mean after booting bbl and riscv-linux, u-boot will still alive > and > handle SBI calls and somethings in S-mode. > > Or u-boot is going to replace the role of bbl ? > > Rick >
Hi Rick, Not exactly, my current boot flow is as follows. 1. u-boot SPL starts in machine mode and jumps to bbl 2. bbl starts u-boot proper in supervisor mode 3. u-boot boots the kernel bbl is still active once Linux has booted and is used there for its SBI implementation. Hope this helps. Thanks, Lukas > > > > > > > Thank you for your patches, it's great to see better support > for > > > > > RISC-V in u-boot! I will add a few comments based on what I > have > > > > > learned so far from working with u-boot on RISC-V. > > > > > > > > > > > > > It's a good start. RISC-V is pretty new and needs more > developers > > > > :-) > > > > > > > > > > Exactly :) > > > > > > Thanks, > > > Lukas _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
