Date: Sun, 9 Sep 2018 12:22:55 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Yuri Pankov <yuripv@yuripv.net> Cc: freebsd-hackers <freebsd-hackers@freebsd.org> Subject: Re: acpi, pci, spibus -- tying it all together Message-ID: <20180909092255.GM3161@kib.kiev.ua> In-Reply-To: <30e41db8-a56d-e916-0490-7e184063a811@yuripv.net> References: <30e41db8-a56d-e916-0490-7e184063a811@yuripv.net>
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On Sun, Sep 09, 2018 at 10:25:44AM +0300, Yuri Pankov wrote:
> I have modified intelspi to attach to SPI master (Sunrise Point-H Serial
> IO SPI) located on pci bus, and on attach I have the spibus0 and spibus1
> buses added.
>
> As spibus is not self-enumerating, the only way to find the slave device
> I need is via acpi bus probe, that works, but I don't see a way to make
> it a child of spibus1 (where it's located).
>
> In ACPI terms it looks like the below (from DSDT):
>
> ...
> \_SB_.PCI0.SPI0 "Device (SPI0)"
> \_SB_.PCI0.SPI1 "Device (SPI1)"
> ...
> Scope (SPI1) {
> Device (SPIT) {
> ...here comes all the data we need,
> including the ACPI ID we can probe...
> }
> }
> ...
>
> I hope that made at least some sense. And the question is if there any
> existing way of tying it all together, and adding that slave device to
> the spibus1 (which only knows about hinted children at the moment)?
I had very similar situation where I wrote NVDIMM driver.
The suggestion I got was to implement DEVICE_IDENTIFY() method. It
gets the driver_t and the parent bus device_t arguments. In the method,
you create children' device_t, iterating over the ACPI enumerated entries.
Practically, you would use acpica AcpiWalkNamespace(ACPI_TYPE_DEVICE, ...)
function and call BUS_ADD_CHILD() when needed. Set the ACPI handle for
the created child. [Get the Intel' ACPICA reference manual to understand
the KPI].
Then probe does nothing, and attach verifies against the handle.
You can see that in https://kib.kiev.ua/kib/nvdimm.7.patch
nvdimm_identify(), nvdimm_foreach_acpi(), and nvdimm_create_dev().
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