Re: [PATCH V5 3/3] ARM64 LPC: LPC driver implementation on Hip06

Arnd Bergmann
2016-11-09T21:37:26Z

On Wednesday, November 9, 2016 12:10:43 PM CET Gabriele Paoloni wrote:
> > On Tuesday, November 8, 2016 11:47:09 AM CET zhichang.yuan wrote:
> > > + /*
> > > + * The first PCIBIOS_MIN_IO is reserved specifically for
> > indirectIO.
> > > + * It will separate indirectIO range from pci host bridge to
> > > + * avoid the possible PIO conflict.
> > > + * Set the indirectIO range directly here.
> > > + */
> > > + lpcdev->io_ops.start = 0;
> > > + lpcdev->io_ops.end = PCIBIOS_MIN_IO - 1;
> > > + lpcdev->io_ops.devpara = lpcdev;
> > > + lpcdev->io_ops.pfin = hisilpc_comm_in;
> > > + lpcdev->io_ops.pfout = hisilpc_comm_out;
> > > + lpcdev->io_ops.pfins = hisilpc_comm_ins;
> > > + lpcdev->io_ops.pfouts = hisilpc_comm_outs;
> >
> > I have to look at patch 2 in more detail again, after missing a few
> > review
> > rounds. I'm still a bit skeptical about hardcoding a logical I/O port
> > range here, and would hope that we can just go through the same
> > assignment of logical port ranges that we have for PCI buses,
> > decoupling
> > the bus addresses from the linux-internal ones.
>
> The point here is that we want to avoid any conflict/overlap between
> the LPC I/O space and the PCI I/O space. With the assignment above
> we make sure that LPC never interfere with PCI I/O space.

But we already abstract the PCI I/O space using dynamic registration.
There is no need to hardcode the logical address for ISA, though
I think we can hardcode the bus address to start at zero here.

Arnd