Re: [PATCH v16 0/9] LPC: legacy ISA I/O support

On 06/03/2018 11:21, Andy Shevchenko wrote:

On Tue, 2018-03-06 at 18:47 +0800, John Garry wrote:

quoted

This patchset supports the IPMI-bt device attached to the Low-Pin-
Count
interface implemented on Hisilicon Hip06/Hip07 SoC.
                        -----------
                        | LPC host|
                        |         |
                        -----------
                             |
                _____________V_______________LPC
                  |                       |
                  V                       V
                                     ------------
                                     |  BT(ipmi)|
                                     ------------

When master accesses those peripherals beneath the Hip06/Hip07 LPC, a
specific
LPC driver is needed to make LPC host generate the standard LPC I/O
cycles with
the target peripherals'I/O port addresses. But on curent arm64 world,
there is
no real I/O accesses. All the I/O operations through in/out accessors
are based
on MMIO ranges; on Hip06/Hip07 LPC the I/O accesses are performed
through driver
specific accessors rather than MMIO.
To solve this issue and keep the relevant existing peripherals'
drivers untouched,
this patchset:
   - introduces a generic I/O space management framework, logical PIO,
to support
      I/O operations on host controllers operating either on MMIO
buses or on buses
     requiring specific driver I/O accessors;
   - redefines the in/out accessors to provide a unified interface for
both MMIO
     and driver specific I/O operations. Using logical PIO, th call of
in/out() from
     the host children drivers, such as ipmi-si, will be redirected to
the
     corresponding device-specific I/O hooks to perform the I/O
accesses.

Based on this patch-set, all the I/O accesses to Hip06/Hip07 LPC
peripherals can
be supported without any changes on the existing ipmi-si driver.

The whole patchset has been tested on Hip07 D05 board both using DTB
and ACPI.

quoted

V15 thread here: https://lkml.org/lkml/2018/2/26/584

Thanks for an update.
Though I answered to previous thread.

Summary: I'm fine with the series as long as maintainers are fine
(Rafael et al.). On personal side I think that the handler approach is
better. Details are in v15 thread.

Hi Andy,

Thanks for your input and continued support. As I mentioned in reply in 
v15, the handler support would (or has) faced issues. And Rafael seems 
fine with deferring the probe to the LLDD in Patch #7/9

Anyway, let's wait for any more input.

Much appreciated,
John