From: John Garry <john.garry@huawei.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jiancheng Xue <xuejiancheng@hisilicon.com>,
chenxiang66@hisilicon.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
tudor.ambarus@microchip.com, Linuxarm <linuxarm@huawei.com>,
linux-spi <linux-spi@vger.kernel.org>,
Marek Vasut <marek.vasut@gmail.com>,
Mark Brown <broonie@kernel.org>,
"open list:MEMORY TECHNOLOGY..." <linux-mtd@lists.infradead.org>,
liusimin4@huawei.com,
Mika Westerberg <mika.westerberg@linux.intel.com>,
wanghuiqiang <wanghuiqiang@huawei.com>,
fengsheng5@huawei.com
Subject: Re: [PATCH v2 2/3] spi: Add HiSilicon v3xx SPI NOR flash controller driver
Date: Fri, 31 Jan 2020 12:03:19 +0000 [thread overview]
Message-ID: <136bd652-dcb9-3efa-a92f-2263cbf840ad@huawei.com> (raw)
In-Reply-To: <CAHp75Ve=ZwJe2XV8Y1UN6sMe1ZHOBwUtRUD=aGqhR4Gc7BNUcg@mail.gmail.com>
On 31/01/2020 11:39, Andy Shevchenko wrote:
> On Fri, Jan 31, 2020 at 12:08 PM John Garry <john.garry@huawei.com> wrote:
>>
>> 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@kernel.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,
>>
Hi Andy,
>> 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/
>>
>
> The 19.6.126 describes the SPI resource, in particular:
>
> ---8<---8<---
> DataBitLength is the size, in bits, of the smallest transfer unit for
> this connection. _LEN is automatically
> created to refer to this portion of the resource descriptor.
> ---8<---8<---
>
> Is it what you are looking for? (As far as I know most of the
> firmwares simple abuse this field among others)
I didn't think so - I thought that there was a distinction between width
and length in SPI terms.
So how do you find that most firmwares abuse this field? AFAICS, linux
kernel doesn't interpret this field at all.
>
>> There seems to be an avenue there for raising new features for the spec.
>> I (or my org) can't participate in AWSG.
>
> But have you read 19.6.126?
>
Maybe some clarification at least could be achieved :)
Cheers,
John
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next prev parent reply other threads:[~2020-01-31 12:03 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 14:08 [PATCH v2 0/3] HiSilicon v3xx SFC driver John Garry
2019-12-09 14:08 ` [PATCH v2 1/3] mtd: spi-nor: hisi-sfc: Try to provide some clarity on which SFC we are John Garry
2020-01-16 11:03 ` Tudor.Ambarus
2019-12-09 14:08 ` [PATCH v2 2/3] spi: Add HiSilicon v3xx SPI NOR flash controller driver John Garry
2020-01-09 15:54 ` John Garry
2020-01-09 21:28 ` Mark Brown
2020-01-10 11:55 ` John Garry
2020-01-10 14:07 ` Mark Brown
2020-01-10 14:58 ` John Garry
2020-01-10 15:12 ` Mark Brown
2020-01-10 16:09 ` John Garry
2020-01-10 19:31 ` Andy Shevchenko
2020-01-13 10:09 ` John Garry
2020-01-13 11:42 ` Mark Brown
2020-01-13 13:01 ` John Garry
2020-01-13 14:06 ` Mark Brown
2020-01-13 14:17 ` Andy Shevchenko
2020-01-13 14:27 ` Mark Brown
2020-01-13 14:34 ` Andy Shevchenko
2020-01-31 10:08 ` John Garry
2020-01-31 11:39 ` Andy Shevchenko
2020-01-31 12:03 ` John Garry [this message]
2020-01-31 15:46 ` Andy Shevchenko
2020-01-31 16:26 ` John Garry
2020-02-01 11:34 ` Mark Brown
2020-02-01 11:32 ` Mark Brown
2020-01-10 19:59 ` Applied "spi: Add HiSilicon v3xx SPI NOR flash controller driver" to the spi tree Mark Brown
2019-12-09 14:08 ` [PATCH v2 3/3] MAINTAINERS: Add a maintainer for the HiSilicon v3xx SFC driver John Garry
2020-01-10 19:59 ` Applied "MAINTAINERS: Add a maintainer for the HiSilicon v3xx SFC driver" to the spi tree Mark Brown
2019-12-16 14:52 ` [PATCH v2 0/3] HiSilicon v3xx SFC driver John Garry
2019-12-16 14:56 ` Mark Brown
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