Re: [PATCH v3 00/16] hw/riscv: Add Microchip PolarFire SoC Icicle Kit board support

[Leif Lindholm]

On Mon, Sep 07, 2020 at 18:24:06 +0800, Bin Meng wrote:
> Hi Leif,
> 
> 
> On Sun, Sep 6, 2020 at 9:08 AM Leif Lindholm <leif@nuviainc.com> wrote:
> >
> > On Tue, Sep 01, 2020 at 09:38:55 +0800, Bin Meng wrote:
> > > From: Bin Meng <bin.meng@windriver.com>
> > >
> > > This adds support for Microchip PolarFire SoC Icicle Kit board.
> > > The Icicle Kit board integrates a PolarFire SoC, with one SiFive's
> > > E51 plus four U54 cores and many on-chip peripherals and an FPGA.
> > >
> > > For more details about Microchip PolarFire SoC, please see:
> > > https://www.microsemi.com/product-directory/soc-fpgas/5498-polarfire-soc-fpga
> > >
> > > The Icicle Kit board information can be found here:
> > > https://www.microsemi.com/existing-parts/parts/152514
> > >
> > > Unlike SiFive FU540, the RISC-V core resect vector is at 0x20220000.
> > > The RISC-V CPU and HART codes has been updated to set the core's
> > > reset vector based on a configurable property from machine codes.
> > >
> > > The following perepherals are created as an unimplemented device:
> > >
> > > - Bus Error Uint 0/1/2/3/4
> > > - L2 cache controller
> > > - SYSREG
> > > - MPUCFG
> > > - IOSCBCFG
> > > - GPIO
> > >
> > > The following perepherals are emulated:
> > > - SiFive CLINT
> > > - SiFive PLIC
> > > - PolarFire SoC Multi-Mode UART
> > > - SiFive PDMA
> > > - Cadence eMMC/SDHCI controller
> > > - Cadence Gigabit Ethernet MAC
> > >
> > > The BIOS image used by this machine is hss.bin, aka Hart Software
> > > Services, which can be built from:
> > > https://github.com/polarfire-soc/hart-software-services
> > >
> > > To launch this machine:
> > > $ qemu-system-riscv64 -M microchip-icicle-kit -smp 5 \
> > >     -bios path/to/hss.bin -sd path/to/sdcard.img \
> > >     -nic tap,ifname=tap,script=no,model=cadence_gem \
> > >     -display none -serial stdio \
> > >     -chardev socket,id=serial1,path=serial1.sock,server,wait \
> > >     -serial chardev:serial1
> >
> > I finally got around to building the sd image from
> > https://github.com/polarfire-soc/polarfire-soc-buildroot-sdk,
> > and I can successfully boot to prompt using that, and the (hacked)
> > hss.bin I verified previously - also with this v3.
> >
> 
> Good to know!
> 
> > However, unless I add the "-nic user,model=cadence_gem \" shown in
> > https://wiki.qemu.org/Documentation/Platforms/RISCV#Microchip_PolarFire_SoC_Icicle_Kit
> > but not here, I do not have functioning networking. (It is not obvious
> > to me why this is needed.)
> >
> 
> Sorry I don't understand what the issue is?

The instructions in this cover letter does not contain the line
  "-nic user,model=cadence_gem \"

The instruction in the wiki does.
The instruction in the wiki works, the instruction in the cover letter
does not.

It is not clear to me why both lines are needed.

> > > The memory is set to 1 GiB by default to match the hardware.
> >
> > Which hardware is this?
> > https://www.crowdsupply.com/microchip/polarfire-soc-icicle-kit lists
> > 2GiB.
> 
> It's this same board. But I believe the crowdsupply webpage has the
> wrong information. The board I got only has 1GB memory.

The diagram on https://www.microsemi.com/existing-parts/parts/152514
also says 2GB. Do you have any channel to Microchip to clarify this?

> > > A sanity check on ram size is performed in the machine init routine
> > > to prompt user to increase the RAM size to > 1 GiB when less than
> > > 1 GiB ram is detected.
> >
> > There is currently no visible effect in firmware from setting memory size 
> > to >
> > 1GiB (hss says 1GB, u-boot says 1GB, Linux sees 1GB).
> > Are there any plans to address this in future versions?
> 
> HSS is using hardcoded 1GB memory size and that's why in QEMU the
> minimum required memory size is 1GB. Setting less than 1GB size blocks
> HSS to load the 2nd stage bootloader U-Boot into the memory. Both
> U-Boot and Linux DTS files set the memory size to 1GB, so that's why
> both of them see only 1GB. Setting memory >1G does not affect U-Boot
> and Linux though. You can however manually edit the U-Boot and Linux
> DTS files to have a large RAM size to match QEMU -m option.

Understood, thanks.

Best Regards,

Leif