RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Gabriele Paoloni
2017-06-13T14:45:25Z

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> Sent: 13 June 2017 09:49
> To: Lorenzo Pieralisi
> Cc: Gabriele Paoloni; rafael@kernel.org; Rafael J. Wysocki;
> catalin.marinas@arm.com; will.deacon@arm.com; robh+dt@kernel.org;
> frowand.list@gmail.com; bhelgaas@google.com; arnd@arndb.de; linux-arm-
> kernel@lists.infradead.org; mark.rutland@arm.com;
> brian.starkey@arm.com; olof@lixom.net; benh@kernel.crashing.org; linux-
> kernel@vger.kernel.org; linux-acpi@vger.kernel.org; Linuxarm; linux-
> pci@vger.kernel.org; minyard@acm.org; John Garry; xuwei (O)
> Subject: Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO
> devices before scanning
>
> On Mon, Jun 12, 2017 at 04:57:00PM +0100, Lorenzo Pieralisi wrote:
> > I had a more in-depth look at this series and from my understanding
> > the problem are the following to manage the LPC bindings in ACPI.
> >
> > (1) Child devices of an LPC controller require special handling when
> > filling their resources (ie they need to be translated - in DT
> > that's guaranteed by the "isa" binding, in ACPI it has to be
> > done by new code)
> > (2) In DT systems, LPC child devices are created by the LPC bus
> > controller driver through an of_platform_populate() call with
> > the LPC controller node as the fwnode root. For ACPI to work
> > the same way there must be a way to prevent LPC children to
> > be enumerated in acpi_default_enumeration() something like
> > I2C does (and then the LPC driver would enumerate its children as
> > DT does)
> >
> > I am not sure how (1) and (2) can be managed with current ACPI
> bindings
> > and kernel code - I suspect it may be done by mirroring what's done
> > for I2C but I am not sure, that's why I CC'ed Mika (ie the LPC
> adapter
> > is matched as a platform device and it takes care of enumerating its
> > children - problem though is preventing enumeration from core ACPI
> code).
>
> Is there an example ASL showing how these LPC devices are
> currently presented in ACPI?

Please find below the asl sketch for our LPC and IPMI

//
// LPC
//

Scope(_SB) {
Device (LPC0) {
Name (_HID, "HISI0191") // HiSi LPC
Name (_CRS, ResourceTemplate () {
Memory32Fixed (ReadWrite, 0xa01b0000, 0x1000)
})
}

Device (LPC0.IPMI) {
Name (_HID, "IPI0001")
Method (_IFT) {
Return (0x03)
}
Name (LORS, ResourceTemplate() {
QWordIO (
ResourceConsumer,
MinNotFixed, // _MIF
MaxNotFixed, // _MAF
PosDecode,
EntireRange,
0x0, // _GRA
0xe4, // _MIN
0x3fff, // _MAX
0x0, // _TRA
0x04, // _LEN
, ,
BTIO
)
})
CreateQWordField (LORS, BTIO._MIN, CMIN)
CreateQWordField (LORS, BTIO._MAX, CMAX)
CreateQWordField (LORS, BTIO._LEN, CLEN)

Method (_PRS, 0) {
Return (LORS)
}

Method (_CRS, 0) {
Return (LORS)
}
Method (_SRS, 1) {
CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MIN, IMIN)
Store (IMIN, CMIN)
CreateQWordField (Arg0, \_SB.LPC0.IPMI.BTIO._MAX, IMAX)
Store (IMAX, CMAX)
}
}
[...]
}

Many thanks
Gab