Re: [PATCH v15 0/9] LPC: legacy ISA I/O support

From: John Garry <john.garry@huawei.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	mika.westerberg@linux.intel.com, rafael@kernel.org,
	lorenzo.pieralisi@arm.com, rjw@rjwysocki.net,
	hanjun.guo@linaro.org, robh+dt@kernel.org, bhelgaas@google.com,
	arnd@arndb.de, mark.rutland@arm.com, olof@lixom.net,
	dann.frazier@canonical.com, andy.shevchenko@gmail.com,
	robh@kernel.org
Cc: joe@perches.com, benh@kernel.crashing.org,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-acpi@vger.kernel.org, linuxarm@huawei.com, minyard@acm.org,
	devicetree@vger.kernel.org, linux-arch@vger.kernel.org,
	rdunlap@infradead.org, gregkh@linuxfoundation.org,
	akpm@linux-foundation.org, frowand.list@gmail.com, agraf@suse.de
Subject: Re: [PATCH v15 0/9] LPC: legacy ISA I/O support
Date: Fri, 2 Mar 2018 10:48:21 +0000	[thread overview]
Message-ID: <5b7024af-33c8-48c8-22bc-8d36ca3eadd8@huawei.com> (raw)
In-Reply-To: <1519933978.10722.366.camel@linux.intel.com>

On 01/03/2018 19:52, Andy Shevchenko wrote:
> On Tue, 2018-02-27 at 00:40 +0800, John Garry wrote:
>> > 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.
>> >
> I did a review and don't see the patch 8 is ready to go.
>
> So, to move things forward I may suggest to reorder series that some
> small preparation stuff can go first w/o dependency to the actual Logic
> PIO / LPC.
>

Hi Andy,

As mentioned in the reply to patch #8, as a practical exercise I don't 
see the reason to change it now. Let's conclude that issue first before 
deciding on patchset revising.

Thanks very much,
John