phosphor-ipmi-flash: Update over eSPI interface

[Oskar Senft]

Hi Harry

I've done some experiments with the USB virtual NIC on the AST2500 and
found that to work rather nicely.

We're currently investigating in my team to use that interface as the
primary method for transferring data between the host and the BMC. From
what I can tell, this seems to be the fastest, most secure method. The
advantage also is that it doesn't need any low-level HW / memory access on
the host. However, the host still needs to have the USB NIC on its side
supported (driver) and configured (IP address). For our environment
(Linux), this is easy to achieve.

It should be possible to update the phosphor-ipmi-flash BMC and host side
implementation to use a USB NIC for data transfer. However, we haven't
investigated those details yet.

Other methods for data transfer (LPC, PCIe, eSPI, SuperI/O) all seem to
open up a large security hole in the AST2500.

Oskar.

On Wed, Sep 11, 2019 at 10:45 AM Patrick Venture <venture at google.com> wrote:

> On Wed, Sep 11, 2019 at 1:59 AM Harry Sung1 <hsung1 at lenovo.com> wrote:
> >
> >
> > > On Mon, Sep 9, 2019 at 7:01 AM Oskar Senft <osk at google.com> wrote:
> > > >
> > > > Hi Harry
> > > >
> > > > What's the behavior on eSPI? I assume you still have the
> aspeed-lpc-ctrl
> > > enabled, right?
> > > >
> > > > Thanks
> > > > Oskar.
> >
> > Hi Oskar,
> > Yes, I still enabled the aspeed-lpc-ctrl in my build. Because
> phosphor-ipmi-flash has some mandatory actions on /dev/aspeed-lpc-ctrl
> before flash (settings for HICR5, HICR7 and HICR8) even though these
> settings are meaningless for eSPI.
> >
> > Currently, I set ESPI084 (source address) and ESPI088 (target address)
> registers manually because linux seems not have a driver can help us to set
> ESPI084 and ESPI088.
> >
> > Due to the limitation of AST2500, we can only write 256 bytes in one
> write operation (write shared memory).
> > Based on the test result, it takes about 30 mins to transfer a 32MB
> image over eSPI.
>
> :( wow, that's unfortunately rather slow.
>
> >
> > Thanks,
> > Harry
> > > >
> > > > On Mon, Sep 9, 2019 at 4:41 AM Harry Sung1 <hsung1 at lenovo.com>
> wrote:
> > > >>
> > > >> Hi Patrick,
> > > >>
> > > >>
> > > >>
> > > >> I found “phosphor-ipmi-flash” have not support flash over eSPI yet.
> > > >>
> > > >> May I ask if you have any plans to support flash over eSPI?
> > > >>
> > > >>
> > > >>
> > > >> I have done a simple test about shared memory between host and BMC :
> > > >>
> > > >> The shared memory is work after I set ESPI084 (source address) and
> ESPI088
> > > (target address) registers.
> > > >>
> > > >> But it has an limitation that only 256 bytes are available on each
> page (4KB).
> > > >>
> > > >>
> > > >> For example, if host address starts to write from 0xFE0B0000 (BMC
> > > >> reserved enough memory already)
> > > >>
> > > >> Writable area are:
> > > >>
> > > >> 0xFE0B0000 ~ 0xFE0B00FF
> > > >>
> > > >> 0xFE0B1000 ~ 0xFE0B10FF
> > > >>
> > > >> 0xFE0B2000 ~ 0xFE0B20FF
> > > >>
> > > >> 0xFE0B3000 ~ 0xFE0B30FF
> > > >>
> > > >> …
> > > >>
> > > >> …
> > > >>
> > > >> …
> > > >>
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> Thanks,
> > > >> Harry
> > >
> > > Harry, currently there's no plan to implement it as I have no method
> of testing
> > > it,  However, it should prove fairly straightforward to add another
> option to
> > > the transport mechanism list.  Please let me know if you run into any
> > > blockers.
> >
> > Hi Patrick,
> > Got it. The better way to set eSPI register is setting them by the
> driver, right?
> > For quick validation, I am going to use the " ipmilpc" interface and set
> necessary eSPI registers manually.
>
> I don't know as much about the eSPI variation of this.  ipmilpc uses
> whatever LPC memory shared option is available (in coordination with
> the host+bmc).  If eSPI doesn't use the aspeed-lpc-ctrl driver for
> what it needs, then perhaps a new option should be added ipmiespi?
>
> >
> > Thanks,
> > Harry
>
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