[rescue] SBusFPGA update: USB Host, 256 MiB DDR3 RAM disk, ... (Was: Re: A SBus card for SPARCstation designed in 2020...)

[Romain Dolbeau]

Hello,

Following up on a previous post...

Le sam. 12 dC)c. 2020 C  19:12, Romain Dolbeau <romain at dolbeau.org> a C)crit
:
> Following up on my own idea, this might interest some people on these
lists:
> Le jeu. 17 sept. 2020 C  15:29, Romain Dolbeau <romain at dolbeau.org> a C)crit
:
> > The motivation - I'm kind of wondering how much efforts it would take
> > to put a modern [not-so-]small FPGA on a SBus card

The current status is visible in the repository
<https://github.com/rdolbeau/SBusFPGA> (and a picture on Reddit
<https://www.reddit.com/r/vintagecomputing/comments/p98pl1/sparcstation_20_wi
th_fpgabased_256_mib_ddr3_ram/>).

The completely re-written gateware includes a 256 MiB RAM disk (for
e.g. fast swap) and USB OHCI host controller. It only took 23 years to
get USB 1.1 on a SPARCstation :-) (and the hardware needs a redesign,
as there's no proper connector in the current version, the picture
shows the ugly truth). Still working on crypto, but this time with an
elliptic curve 25519 engine (for e.g. ssh handshake), and the SW side
is still the primary issue... The micro-sd could be supported in HW
with the Litex gateware, but the specific driver would need porting
from Linux to NetBSD (unlike USB OHCI which only needed the SBus ->
OHCI shim, the OHCI driver is NetBSD's stock one, and having USB mass
storage support makes the micro-sd less critical).

There's no boot support for USB; there's a stack available in Forth
for recent versions of OpenFirmware but it won't work on an OpenBoot
2.x system like the SS20 (and I couldn't figure out how to make it
work/backport).

#####
(dolbeau)ss20:~> cpuctl identify 0
cpu0: mid 8: TI,TMS390Z55 @ 60 MHz, on-chip FPU
cpu0: physical 20K instruction (64 b/l), 16K data (32 b/l), 1024K
external (32 b/l): cache
enabled
cpu0: SPARC v8
(dolbeau)ss20:~> cpuctl identify 1
cpu1: mid 10: TI,TMS390Z55 @ 60 MHz, on-chip FPU
cpu1: physical 20K instruction (64 b/l), 16K data (32 b/l), 1024K
external (32 b/l): cache
enabled
cpu1: SPARC v8
(dolbeau)ss20:~> usbdevs
addr 1: OHCI root hub, NetBSD
addr 2: USB 2.0 Hub, vendor 1a40
 addr 3: PS/2+USB Mouse, vendor 04f3
(dolbeau)ss20:~> swapctl -l
Device               512-blocks     Used    Avail Capacity  Priority
/dev/sbusfpga_sdram0     524288        0   524288     0%    0
#####
(the intermediate USB Hub supplies the needed VBus as I don't have
power management on the board).

Cordially,

--
Romain Dolbeau