[flashrom] Re: adding support for PCIe SPI flash? VL805 USB

[John Paul Morrison]

Thanks Carl-Daniel

I have a couple of these VL805 cards to test with - I don't have a Pi but
your code should work if I can add the FM25Q04
Not too worried about bricking - cheap on Amazon. From Ubuntuforms it
sounds like you can recover pretty easily from erased firmware using the
windows based VIA programmer.

do you have a tarball/zip/git of your build?

thanks, again,

John Paul

Link to the datasheet:

FM25Q04_ds_eng.pdf (fmsh.com) http://eng.fmsh.com/nvm/FM25Q04_ds_eng.pdf

For the Windows tool my guess is to add this to the firmware updaters
spiflash.ini  but won't be able to test for a couple of days.
The commands seem to be pretty standard and match the datasheet.
I'm not sure about the ClockRate - most flash ships are set to 32 but not
all.
Page size 0x100 (256) is used by almost all but exceptions are MX25L5121E
(0x20)  AT25F512A(0x80), and W25X10BV(0x10)
I haven't looked up all the chips but some of them had a page size of 0x100
but the firmware tool sets a smaller value.
e.g. W25X10BV datasheet says its page size is 0x100 but the tool sets it to
0x10 - maybe there's reasons to program with smaller pages?

[FM25Q04]
FlashID=A112
ReadID=9F
WriteEnable=06
WriteStatus=01
ChipErase=C7
ReadData=03
ReadStatus=05
PageProgram=02
ClockRate=32
PageSize=100

On Tue, Feb 2, 2021 at 2:53 PM Carl-Daniel Hailfinger <
[e-mail]> wrote:
> Hi John Paul,
>
> Am 02.02.21 um 20:12 schrieb John Paul Morrison:
> > I'm just starting to look at fashrom to see how to read/update SPI
> > flash on a PCIe card
> >
> > lspci -d 1106:3483
> > 01:00.0 USB controller: VIA Technologies, Inc. VL805 USB 3.0 Host
> > Controller (rev 01)
> >
> > There isn't much from Via but the chipset is used in the Raspberry Pi
> > 4 and the Pi firmware provides a flash tool vl805 (no source code of
> > course!)
>
> I have a working flashrom driver for that host controller, but I need
> testers. Back when I wrote the driver at the end of 2019 I didn't even
> have a Raspberry Pi 4 and was just reverse engineering the behaviour
> from traces with some help from clever on IRC.
> > I can run it on Intel with Qemu - unfortunately for me the tool is
> > hard coded for a different SPI flash chip (and in later Pi hardware
> > seems to have been moved/removed)
> >
> > Inspecting the board and related datasheets (VL800) the chipset has an
> > SPI interface for firmware, and it can be used for PCI BIOS
> > apparently.  The actual SPI chip varies from board to board - mine is
> > FM25Q04 from the data sheet ID=A112. Raspberry Pi seems to use
> > W25X10BV  based on the ID EF10
> >
> > Are there any simple examples of accessing SPI on PCIe cards?
> >
> > sorry for the long post - I've included a bit  more info on what I
> > could find on the chip
>
> Thanks.
>
> I really should update the VL805 patch against current flashrom and
> submit it.
> > thanks
> >
> > John Paul
>
> Regards,
> Carl-Daniel
> > Other info on the chip:
> >
> > I can  read the firmware version easily:
> >
> > sudo lspci -d 1106:3483 -xxx | awk '/^50:/ { print "VL805 FW version:
> > " $5 $4 $3 $2 }'
> >
> > I can use strace to see what vl805 doing - I can make out some SPI
> > commands - here it reads the SPI flash chip ID:
> > openat(AT_FDCWD, "/sys/bus/pci/devices/0000:01:00.0/config", O_RDWR) = 4
> > (bunch of reads/writes)
> > pread64(4, "\22\241\22\241", 4, 124)    = 4
> > write(1, "R Rx_REG0 a112a112\n", 19)    = 19
> >
> > sudo ~/vl805/vl805 -d
> > VL805 FW version: 00013600
> > W CHIP_SEL 00000001
> > R PCI_WB_EN ffffffff
> > W PCI_WB_EN ffffff01
> > R STOP_POLLING 00000001
> > W STOP_POLLING 00000001
> > W CTRL_REG 000005a0
> > W CLK_DIV 0000000a
> > W CHIP_SEL 00000000
> > W Tx_REG0 90000000
> > W CTRL_REG 000005c0
> > R Rx_REG0 a112a112
> > W CHIP_SEL 00000001
> > flash ID mismatch - found a112, expected 0000ef10
> >
> > I was able to find a Windows based firmware updater which supports
> > about 20 different SPI chips - people have reported adding new
> > chipsets, looks like I have to add mine as well.
> > The flash tool runs under wine but it can't read anything - will have
> > to find a fix or run in a vm.
> >
> > Via SpiFlash.ini:
> > [MX25L512]
> > FlashID=C22010
> > ReadID=9F
> > WriteEnable=06
> > WriteStatus=01
> > ChipErase=60
> > ReadData=03
> > ReadStatus=05
> > PageProgram=02
> > ClockRate=32
> > PageSize=100
> >
> > Raspberry Pi 4 ?
> > [W25X10BV]
> > FlashID=EF10
> > ReadID=90000000
> > WriteEnable=06
> > WriteStatus=01
> > ChipErase=C7
> > ReadData=03
> > ReadStatus=05
> > PageProgram=02
> > ClockRate=32
> > PageSize=10