Messages in this thread | | | Subject | Re: [PATCH v2 2/3] spi: Add HiSilicon v3xx SPI NOR flash controller driver | From | John Garry <> | Date | Fri, 31 Jan 2020 12:03:19 +0000 |
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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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