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Re: [PATCH v1 3/3] ARM64 LPC: update binding doc

From Arnd Bergmann <arnd@arndb.de>
Newsgroups linux.kernel
Subject Re: [PATCH v1 3/3] ARM64 LPC: update binding doc
Date 2016-01-13 10:30 +0100
Message-ID <qQpUD-63W-23@gated-at.bofh.it> (permalink)
References <qMPXk-5nR-5@gated-at.bofh.it> <qQmWJ-43x-3@gated-at.bofh.it> <qQng6-4bv-11@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Wednesday 13 January 2016 14:34:47 Rongrong Zou wrote:
> On 2016/1/13 13:53, Benjamin Herrenschmidt wrote:
> > On Tue, 2016-01-12 at 23:52 +0100, Arnd Bergmann wrote:
> >> On Tuesday 12 January 2016 15:13:35 liviu.dudau@arm.com wrote:
> >>>> int of_address_to_resource(struct device_node *dev, int index,
> >>>>                            struct resource *r)
> >>>> {
> >>>>         ...
> >>>>         /* flags can be get here, without ranges property reqired.
> >>>>          * if the reg = <0x0 0xe4 4>, I can get flag of
> >> IORESOURCE_MEM,
> >>>>          * if the reg = <0x1 0xe4 4>, I can get flag of
> >> IORESOURCE_IO,
> >>>
> >>> That is strange, the parent node has #address-cells = <2> so the
> >> first two numbers should be part
> >>> of the address and not influence the flags. Can you add some
> >> debugging in of_get_address() and
> >>> try to figure out what bus is used in  *flags = bus-
> >>> get_flags(prop) ?
> >>>
> >>>
> >>
> >> This is the standard ISA binding. The first cell is the address space
> >> (IO or MEM), the second cell is the address within that space. This
> >> is similar to how PCI works.
> >
> > Picking up that mid-way, I have LPC busses on power and am using a
> > similar binding. I'll try to grab some examples and review the
> > document tomorrow (only just noticed it while unpiling emails post-
> > vacation).

I really should have thought of that, as you mentioned already that
there is an ast2400 on those machines, and no I/O space on the PCI
bus.

Too bad we have to keep the I/O workarounds alive on PowerPC now,
I was already hoping they could go away after spider-pci gets phased
out.

> Thanks for reviewing this, I found a similar implementation at arch/powerpc/
> platform/powernv/opal-lpc.c and I had get some ideas from your work. It is
> nice to me. I'm expecting your suggestion.Thanks in advance.

Unfortunately, the way that PCI host bridges on PowerPC are handled
is a bit different from what we do on ARM64, otherwise the obvious
solution would be to move the I/O workarounds to an architecture
independent location. Maybe it's still possible, but that also requires
some refactoring then.

	Arnd

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Thread

Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-03 13:30 +0100
  Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-04 12:20 +0100
    Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@gmail.com> - 2016-01-04 17:00 +0100
      Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-04 17:40 +0100
        Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-05 13:10 +0100
          Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-05 13:30 +0100
            Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-06 14:40 +0100
              Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-07 04:40 +0100
            Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rolland Chau <zourongrong@gmail.com> - 2016-01-10 10:40 +0100
              Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@gmail.com> - 2016-01-10 14:40 +0100
    Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-11 17:20 +0100
      Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@gmail.com> - 2016-01-12 03:40 +0100
        Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-12 10:10 +0100
          Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-12 10:30 +0100
            Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-12 11:20 +0100
              Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-12 12:10 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-12 12:30 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@huawei.com> - 2016-01-12 13:00 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-12 16:20 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-13 00:00 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Benjamin Herrenschmidt <benh@kernel.crashing.org> - 2016-01-13 07:20 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@gmail.com> - 2016-01-13 07:40 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-13 10:30 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-13 11:20 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-13 11:40 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-13 11:20 +0100
              Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-13 00:00 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-13 11:10 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Arnd Bergmann <arnd@arndb.de> - 2016-01-13 11:40 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Rongrong Zou <zourongrong@gmail.com> - 2016-01-13 12:10 +0100
                Re: [PATCH v1 3/3] ARM64 LPC: update binding doc liviu.dudau@arm.com - 2016-01-13 12:30 +0100

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