[Pdbg] [PATCH 2/3] add i2cm from bmc

[Alistair Popple]

On Thursday, 11 April 2019 2:30:32 AM AEST Joel Stanley wrote:
> On Wed, 10 Apr 2019 at 02:31, Alistair Popple <alistair at popple.id.au> wrote:
> > > @@ -46,7 +47,10 @@ static int kernel_fsi_getcfam(struct fsi *fsi,
> > > uint32_t
> > > addr64, uint32_t *value) return errno;
> > > 
> > >       }
> > > 
> > > -     rc = read(fsi_fd, &tmp, 4);
> > > +     if (addr == 0x1800)
> > > +             rc = read(fsi_fd, &tmp2, 1);
> > 
> > So this might clarify my comment above - I wonder what this read actually
> > does at the hardware level. In this case it depends on the OpenFSI kernel
> > driver.
> > 
> > Joel do you know if the OpenFSI read() call supports reading a single
> > physical byte from the FSI bus? (rather than reading 4 bytes from the HW
> > and throwing away 3 bytes).
> 
> I had to double check the code. Yes, AFAICT we read a single byte. The
> read is the size requested, we don't throw away bytes.

Interesting, had no idea. We never did make that work for pdbg as I couldn't 
figure out the application.  I suppose reading a single byte from the I2C is 
valid though.
 
- Alistair

> Cheers,
> 
> Joel