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Message-ID: <0252a76d-7e2b-2c70-8b1b-0d041d972098@huawei.com>
Date: Fri, 31 Jan 2020 10:08:19 +0000
From: John Garry <john.garry@...wei.com>
To: Andy Shevchenko <andy.shevchenko@...il.com>,
Mark Brown <broonie@...nel.org>
CC: <chenxiang66@...ilicon.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
<liusimin4@...wei.com>, Linuxarm <linuxarm@...wei.com>,
linux-spi <linux-spi@...r.kernel.org>,
Marek Vasut <marek.vasut@...il.com>,
"open list:MEMORY TECHNOLOGY..." <linux-mtd@...ts.infradead.org>,
<tudor.ambarus@...rochip.com>,
Jiancheng Xue <xuejiancheng@...ilicon.com>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
wanghuiqiang <wanghuiqiang@...wei.com>, <fengsheng5@...wei.com>
Subject: Re: [PATCH v2 2/3] spi: Add HiSilicon v3xx SPI NOR flash controller
driver
On 13/01/2020 14:34, Andy Shevchenko wrote:
> On Mon, Jan 13, 2020 at 02:27:54PM +0000, Mark Brown wrote:
>> On Mon, Jan 13, 2020 at 04:17:32PM +0200, Andy Shevchenko wrote:
>>> On Mon, Jan 13, 2020 at 4:07 PM Mark Brown <broonie@...nel.org> wrote:
>>>> On Mon, Jan 13, 2020 at 01:01:06PM +0000, John Garry wrote:
>>>>> On 13/01/2020 11:42, Mark Brown wrote:
>>
>>>>>> The idiomatic approach appears to be for individual board vendors
>>>>>> to allocate IDs, you do end up with multiple IDs from multiple
>>>>>> vendors for the same thing.
>>
>>>>> But I am not sure how appropriate that same approach would be for some 3rd
>>>>> party memory part which we're simply wiring up on our board. Maybe it is.
>>
>>>> It seems to be quite common for Intel reference designs to assign
>>>> Intel IDs to non-Intel parts on the board (which is where I
>>>> became aware of this practice).
>>
>>> Basically vendor of component in question is responsible for ID, but
>>> it seems they simple don't care.
>>
>> AFAICT a lot of the time it seems to be that whoever is writing
>> the software ends up assigning an ID, that may not be the silicon
>> vendor.
>
> ...which is effectively abusing the ACPI ID allocation procedure.
>
> (And yes, Intel itself did it in the past — see badly created ACPI IDs
> in the drivers)
>
Hi Mark,
About this topic of ACPI having no method to describe device buswidth in
the resource descriptor, it may be an idea for me to raise a Tianocore
feature request @ https://bugzilla.tianocore.org/
There seems to be an avenue there for raising new features for the spec.
I (or my org) can't participate in AWSG.
I would have no concrete proposal for spec update for now, though.
Hopefully others with more expertise could contribute.
In the meantime, I have an RFC for using DMI to quirk support for this
on the driver - I can share when ready.
Thanks,
John
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