Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1663836 > unrolled thread

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

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> - 2017-06-12 18:10 +0200
    RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-13 09:30 +0200
    Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-13 11:00 +0200
      RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-13 16:50 +0200
        Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-13 17:20 +0200
          RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-13 21:10 +0200
            Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-13 22:10 +0200
              RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-15 20:10 +0200
                Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-16 10:40 +0200
                  Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning "Rafael J. Wysocki" <rafael@kernel.org> - 2017-06-16 13:30 +0200
                    Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-16 14:10 +0200
                      Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning "Rafael J. Wysocki" <rafael@kernel.org> - 2017-06-16 14:30 +0200
                        RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-19 12:00 +0200
                          RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO  devices before scanning Gabriele Paoloni <gabriele.paoloni@huawei.com> - 2017-06-19 12:10 +0200
                          Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices  before scanning Mika Westerberg <mika.westerberg@linux.intel.com> - 2017-06-19 12:10 +0200

#1663836 — Re: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

[+Mika]

Gab, Rafael,

On Tue, Jun 06, 2017 at 09:55:53AM +0100, Lorenzo Pieralisi wrote:
> Hi Gab, Rafael,
> 
> On Wed, May 31, 2017 at 10:24:47AM +0000, Gabriele Paoloni wrote:
> 
> [...]
> 
> > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > > index e39ec7b..37dd23c 100644
> > > > --- a/drivers/acpi/scan.c
> > > > +++ b/drivers/acpi/scan.c
> > > > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> > > >  	acpi_int340x_thermal_init();
> > > >  	acpi_amba_init();
> > > >  	acpi_watchdog_init();
> > > > +	acpi_indirectio_scan_init();
> 
> Unfortunately this is becoming a pattern and we are ending up
> with a static ordering of "subsystems" init (even though for this
> LPC series it is just the Hisilicon driver that requires this call)
> and I am not sure I see any way of avoiding it. I think that's always
> been the case in x86, with fewer subsystems/kernel paths to care
> about, I wanted to flag this up though to check your opinion since
> I am not sure this is the right direction we are taking.
> 
> I also think that relying on _DEP to build any dependency is not
> entirely a) usable (owing to legacy bindings and previous _DEP misuse)
> and b) compliant with ACPI bindings given that _DEP has to be used
> for operation regions only.

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).

I will let Gabriele and Hisilicon guys chime in if I missed something,
which is likely, please let me know your opinion on how this code
can be made functional on ACPI systems - it is uncharted territory.

Thank you !
Lorenzo

> 
> Thoughts ?
> 
> Thanks,
> Lorenzo
> 
> > > >  	acpi_scan_add_handler(&generic_device_handler);
> > > >
> > > > diff --git a/include/acpi/acpi_indirect_pio.h
> > > b/include/acpi/acpi_indirect_pio.h
> > > > new file mode 100644
> > > > index 0000000..efc5c43
> > > > --- /dev/null
> > > > +++ b/include/acpi/acpi_indirect_pio.h
> > > > @@ -0,0 +1,24 @@
> > > > +/*
> > > > + * ACPI support for indirect-PIO bus.
> > > > + *
> > > > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > > > + * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
> > > > + * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
> > > > + *
> > > > + * This program is free software; you can redistribute it and/or
> > > modify
> > > > + * it under the terms of the GNU General Public License version 2 as
> > > > + * published by the Free Software Foundation.
> > > > + */
> > > > +
> > > > +#ifndef _ACPI_INDIRECT_PIO_H
> > > > +#define _ACPI_INDIRECT_PIO_H
> > > > +
> > > > +struct indirect_pio_device_desc {
> > > > +	void *pdata; /* device relevant info data */
> > > > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > > > +};
> > > > +
> > > > +int acpi_set_logic_pio_resource(struct device *child,
> > > > +		struct device *hostdev);
> > > > +
> > > > +#endif
> > > > --
> > > > 2.7.4
> > > >
> > > >

[toc] | [next] | [standalone]

#1664539 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Hi Lorenzo, Rafael

> -----Original Message-----
> From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@arm.com]
> Sent: 12 June 2017 16:57
> To: Gabriele Paoloni; rafael@kernel.org; Rafael J. Wysocki; Mika
> Westerberg
> Cc: 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
> 
> [+Mika]
> 
> Gab, Rafael,
> 
> On Tue, Jun 06, 2017 at 09:55:53AM +0100, Lorenzo Pieralisi wrote:
> > Hi Gab, Rafael,
> >
> > On Wed, May 31, 2017 at 10:24:47AM +0000, Gabriele Paoloni wrote:
> >
> > [...]
> >
> > > > > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
> > > > > index e39ec7b..37dd23c 100644
> > > > > --- a/drivers/acpi/scan.c
> > > > > +++ b/drivers/acpi/scan.c
> > > > > @@ -2035,6 +2035,7 @@ int __init acpi_scan_init(void)
> > > > >  	acpi_int340x_thermal_init();
> > > > >  	acpi_amba_init();
> > > > >  	acpi_watchdog_init();
> > > > > +	acpi_indirectio_scan_init();
> >
> > Unfortunately this is becoming a pattern and we are ending up
> > with a static ordering of "subsystems" init (even though for this
> > LPC series it is just the Hisilicon driver that requires this call)
> > and I am not sure I see any way of avoiding it. I think that's always
> > been the case in x86, with fewer subsystems/kernel paths to care
> > about, I wanted to flag this up though to check your opinion since
> > I am not sure this is the right direction we are taking.
> >
> > I also think that relying on _DEP to build any dependency is not
> > entirely a) usable (owing to legacy bindings and previous _DEP
> misuse)
> > and b) compliant with ACPI bindings given that _DEP has to be used
> > for operation regions only.
> 
> 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)

Correct, LPC resources need to be translated in a virtual IO port
address space.
We cannot strictly follow the ISA bindings as the LPC host does not
define a mapping (through the "range" property) between a CPU address
range and an LPC address range.
Instead LPC has got his own bus accessors; therefore the bus address
range that LPC operates on is directly mapped into the IO port address
range and the IO in/out standard accessors (include/asm-generic/io.h)
are redefined to use the LPC accessors for the virtual IO port address
range that corresponds to LPC. 

> (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)

Correct.

> 
> 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).

Yes my idea was to have a scan handler that enumerate the children devices
and translate its addresses filling dev->resources[] and at the same time
we can modify acpi_default_enumeration() to check acpi_device_enumerated()
before continuing with device enumeration...?

Many thanks
Gab

> 
> I will let Gabriele and Hisilicon guys chime in if I missed something,
> which is likely, please let me know your opinion on how this code
> can be made functional on ACPI systems - it is uncharted territory.
> 
> Thank you !
> Lorenzo
> 
> >
> > Thoughts ?
> >
> > Thanks,
> > Lorenzo
> >
> > > > >  	acpi_scan_add_handler(&generic_device_handler);
> > > > >
> > > > > diff --git a/include/acpi/acpi_indirect_pio.h
> > > > b/include/acpi/acpi_indirect_pio.h
> > > > > new file mode 100644
> > > > > index 0000000..efc5c43
> > > > > --- /dev/null
> > > > > +++ b/include/acpi/acpi_indirect_pio.h
> > > > > @@ -0,0 +1,24 @@
> > > > > +/*
> > > > > + * ACPI support for indirect-PIO bus.
> > > > > + *
> > > > > + * Copyright (C) 2017 Hisilicon Limited, All Rights Reserved.
> > > > > + * Author: Gabriele Paoloni <gabriele.paoloni@huawei.com>
> > > > > + * Author: Zhichang Yuan <yuanzhichang@hisilicon.com>
> > > > > + *
> > > > > + * This program is free software; you can redistribute it
> and/or
> > > > modify
> > > > > + * it under the terms of the GNU General Public License
> version 2 as
> > > > > + * published by the Free Software Foundation.
> > > > > + */
> > > > > +
> > > > > +#ifndef _ACPI_INDIRECT_PIO_H
> > > > > +#define _ACPI_INDIRECT_PIO_H
> > > > > +
> > > > > +struct indirect_pio_device_desc {
> > > > > +	void *pdata; /* device relevant info data */
> > > > > +	int (*pre_setup)(struct acpi_device *adev, void *pdata);
> > > > > +};
> > > > > +
> > > > > +int acpi_set_logic_pio_resource(struct device *child,
> > > > > +		struct device *hostdev);
> > > > > +
> > > > > +#endif
> > > > > --
> > > > > 2.7.4
> > > > >
> > > > >

[toc] | [prev] | [next] | [standalone]

#1664614

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?

[toc] | [prev] | [next] | [standalone]

#1664932 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

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

[toc] | [prev] | [next] | [standalone]

#1664957

On Tue, Jun 13, 2017 at 02:38:26PM +0000, Gabriele Paoloni wrote:
> > 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)
>     }
>   } 
> [...]
> }

Thanks. So this looks pretty much like normal Linux MFD device which we
already have support for adding ACPI bindings to child devices. It
should also support splitting resources to child devices IIRC.

[toc] | [prev] | [next] | [standalone]

#1665118 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> Sent: 13 June 2017 16:10
> To: Gabriele Paoloni
> Cc: Lorenzo Pieralisi; 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 Tue, Jun 13, 2017 at 02:38:26PM +0000, Gabriele Paoloni wrote:
> > > 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)
> >     }
> >   }
> > [...]
> > }
> 
> Thanks. So this looks pretty much like normal Linux MFD device which we
> already have support for adding ACPI bindings to child devices. It
> should also support splitting resources to child devices IIRC.

I am not very familiar with Linux MFD however the main issue here is that
1) for IPMI we want to re-use the standard IPMI driver without touching it:
   see 

   static const struct acpi_device_id acpi_ipmi_match[] = {
         { "IPI0001", 0 },
         { },
   };

   in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard driver
   of an LPC child)

2) We need a way to guarantee that all LPC children are not enumerated
   by acpi_default_enumeration() (so for example if an ipmi node is an LPC#
   child it should not be enumerated, otherwise it should be)
   Currently acpi_default_enumeration() skips spi/i2c slaves by checking:
   1) if the acpi resource type is a serial bus
   2) if the type of serial bus descriptor is I2C or SPI

   For LPC we cannot leverage on any ACPI property to "recognize" that our
   devices are LPC children; hence before I proposed for acpi_default_enumeration()
   to skip devices that have already been enumerated (by calling 
   acpi_device_enumerated() ).

So in the current scenario, how do you think that MFD can help?
Do you see any possible solution?

Many thanks
Gab
  

[toc] | [prev] | [next] | [standalone]

#1665149

On Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> I am not very familiar with Linux MFD however the main issue here is that
> 1) for IPMI we want to re-use the standard IPMI driver without touching it:
>    see 
> 
>    static const struct acpi_device_id acpi_ipmi_match[] = {
>          { "IPI0001", 0 },
>          { },
>    };
> 
>    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard driver
>    of an LPC child)
> 
> 2) We need a way to guarantee that all LPC children are not enumerated
>    by acpi_default_enumeration() (so for example if an ipmi node is an LPC#
>    child it should not be enumerated, otherwise it should be)
>    Currently acpi_default_enumeration() skips spi/i2c slaves by checking:
>    1) if the acpi resource type is a serial bus
>    2) if the type of serial bus descriptor is I2C or SPI
> 
>    For LPC we cannot leverage on any ACPI property to "recognize" that our
>    devices are LPC children; hence before I proposed for acpi_default_enumeration()
>    to skip devices that have already been enumerated (by calling 
>    acpi_device_enumerated() ).
> 
> So in the current scenario, how do you think that MFD can help?

If you look at Documentation/acpi/enumeration.txt there is a chapter
"MFD devices". I think it pretty much maches what you have here. An LPC
device (MFD device) and bunch of child devices. The driver for your LPC
device can specify _HID for each child device. Those are then mached by
the MFD ACPI code to the corresponding ACPI nodes from which platform
devices are created including "IPI0001".

It causes acpi_default_enumeration() to be called but it should be fine
as we are dealing with platform device anyway.

Once the platform device is created your ipmi driver will be probed by
the driver core.

Does that make sense?

[toc] | [prev] | [next] | [standalone]

#1667029 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Hi Mika

> -----Original Message-----
> From: linux-pci-owner@vger.kernel.org [mailto:linux-pci-
> owner@vger.kernel.org] On Behalf Of Mika Westerberg
> Sent: 13 June 2017 21:04
> To: Gabriele Paoloni
> Cc: Lorenzo Pieralisi; 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 Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> > I am not very familiar with Linux MFD however the main issue here is
> that
> > 1) for IPMI we want to re-use the standard IPMI driver without
> touching it:
> >    see
> >
> >    static const struct acpi_device_id acpi_ipmi_match[] = {
> >          { "IPI0001", 0 },
> >          { },
> >    };
> >
> >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
> driver
> >    of an LPC child)
> >
> > 2) We need a way to guarantee that all LPC children are not
> enumerated
> >    by acpi_default_enumeration() (so for example if an ipmi node is
> an LPC#
> >    child it should not be enumerated, otherwise it should be)
> >    Currently acpi_default_enumeration() skips spi/i2c slaves by
> checking:
> >    1) if the acpi resource type is a serial bus
> >    2) if the type of serial bus descriptor is I2C or SPI
> >
> >    For LPC we cannot leverage on any ACPI property to "recognize"
> that our
> >    devices are LPC children; hence before I proposed for
> acpi_default_enumeration()
> >    to skip devices that have already been enumerated (by calling
> >    acpi_device_enumerated() ).
> >
> > So in the current scenario, how do you think that MFD can help?
> 
> If you look at Documentation/acpi/enumeration.txt there is a chapter
> "MFD devices". I think it pretty much maches what you have here. An LPC
> device (MFD device) and bunch of child devices. The driver for your LPC
> device can specify _HID for each child device. Those are then mached by
> the MFD ACPI code to the corresponding ACPI nodes from which platform
> devices are created including "IPI0001".

So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:

	static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
		.pnpid = "IPI0001",
	};

correct?

> 
> It causes acpi_default_enumeration() to be called but it should be fine
> as we are dealing with platform device anyway.

I do not quite understand how declaring such MFD cell above would make sure
that the LPC probe is called before the IPMI device is enumerated...

Could you point me to the code that does this?

Many Thanks
Gab

> 
> Once the platform device is created your ipmi driver will be probed by
> the driver core.
> 
> Does that make sense?

[toc] | [prev] | [next] | [standalone]

#1667526

On Thu, Jun 15, 2017 at 06:01:02PM +0000, Gabriele Paoloni wrote:
> Hi Mika
> 
> > -----Original Message-----
> > From: linux-pci-owner@vger.kernel.org [mailto:linux-pci-
> > owner@vger.kernel.org] On Behalf Of Mika Westerberg
> > Sent: 13 June 2017 21:04
> > To: Gabriele Paoloni
> > Cc: Lorenzo Pieralisi; 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 Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
> > > I am not very familiar with Linux MFD however the main issue here is
> > that
> > > 1) for IPMI we want to re-use the standard IPMI driver without
> > touching it:
> > >    see
> > >
> > >    static const struct acpi_device_id acpi_ipmi_match[] = {
> > >          { "IPI0001", 0 },
> > >          { },
> > >    };
> > >
> > >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
> > driver
> > >    of an LPC child)
> > >
> > > 2) We need a way to guarantee that all LPC children are not
> > enumerated
> > >    by acpi_default_enumeration() (so for example if an ipmi node is
> > an LPC#
> > >    child it should not be enumerated, otherwise it should be)
> > >    Currently acpi_default_enumeration() skips spi/i2c slaves by
> > checking:
> > >    1) if the acpi resource type is a serial bus
> > >    2) if the type of serial bus descriptor is I2C or SPI
> > >
> > >    For LPC we cannot leverage on any ACPI property to "recognize"
> > that our
> > >    devices are LPC children; hence before I proposed for
> > acpi_default_enumeration()
> > >    to skip devices that have already been enumerated (by calling
> > >    acpi_device_enumerated() ).
> > >
> > > So in the current scenario, how do you think that MFD can help?
> > 
> > If you look at Documentation/acpi/enumeration.txt there is a chapter
> > "MFD devices". I think it pretty much maches what you have here. An LPC
> > device (MFD device) and bunch of child devices. The driver for your LPC
> > device can specify _HID for each child device. Those are then mached by
> > the MFD ACPI code to the corresponding ACPI nodes from which platform
> > devices are created including "IPI0001".
> 
> So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:
> 
> 	static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
> 		.pnpid = "IPI0001",
> 	};
> 
> correct?

Yes.

> > 
> > It causes acpi_default_enumeration() to be called but it should be fine
> > as we are dealing with platform device anyway.
> 
> I do not quite understand how declaring such MFD cell above would make sure
> that the LPC probe is called before the IPMI device is enumerated...

In fact it may be that it is not sufficient in this case because the
ACPI core might enumerate child devices before the LPC driver even gets
a chance to probe so you would need to add also scan handler to the
child devices and mark them already enumerated or something like that.

> Could you point me to the code that does this?

Check for example drivers/mfd/intel-lpss.c.

[toc] | [prev] | [next] | [standalone]

#1667645

On Fri, Jun 16, 2017 at 10:33 AM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
> On Thu, Jun 15, 2017 at 06:01:02PM +0000, Gabriele Paoloni wrote:
>> Hi Mika
>>
>> > -----Original Message-----
>> > From: linux-pci-owner@vger.kernel.org [mailto:linux-pci-
>> > owner@vger.kernel.org] On Behalf Of Mika Westerberg
>> > Sent: 13 June 2017 21:04
>> > To: Gabriele Paoloni
>> > Cc: Lorenzo Pieralisi; 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 Tue, Jun 13, 2017 at 07:01:38PM +0000, Gabriele Paoloni wrote:
>> > > I am not very familiar with Linux MFD however the main issue here is
>> > that
>> > > 1) for IPMI we want to re-use the standard IPMI driver without
>> > touching it:
>> > >    see
>> > >
>> > >    static const struct acpi_device_id acpi_ipmi_match[] = {
>> > >          { "IPI0001", 0 },
>> > >          { },
>> > >    };
>> > >
>> > >    in "drivers/char/ipmi/ipmi_si_intf.c" (and in general any standard
>> > driver
>> > >    of an LPC child)
>> > >
>> > > 2) We need a way to guarantee that all LPC children are not
>> > enumerated
>> > >    by acpi_default_enumeration() (so for example if an ipmi node is
>> > an LPC#
>> > >    child it should not be enumerated, otherwise it should be)
>> > >    Currently acpi_default_enumeration() skips spi/i2c slaves by
>> > checking:
>> > >    1) if the acpi resource type is a serial bus
>> > >    2) if the type of serial bus descriptor is I2C or SPI
>> > >
>> > >    For LPC we cannot leverage on any ACPI property to "recognize"
>> > that our
>> > >    devices are LPC children; hence before I proposed for
>> > acpi_default_enumeration()
>> > >    to skip devices that have already been enumerated (by calling
>> > >    acpi_device_enumerated() ).
>> > >
>> > > So in the current scenario, how do you think that MFD can help?
>> >
>> > If you look at Documentation/acpi/enumeration.txt there is a chapter
>> > "MFD devices". I think it pretty much maches what you have here. An LPC
>> > device (MFD device) and bunch of child devices. The driver for your LPC
>> > device can specify _HID for each child device. Those are then mached by
>> > the MFD ACPI code to the corresponding ACPI nodes from which platform
>> > devices are created including "IPI0001".
>>
>> So I guess here in the LPC driver I would have an MFD cell for IPMI. I.e.:
>>
>>       static struct mfd_cell_acpi_match hisi_lpc_ipmi_acpi_match = {
>>               .pnpid = "IPI0001",
>>       };
>>
>> correct?
>
> Yes.
>
>> >
>> > It causes acpi_default_enumeration() to be called but it should be fine
>> > as we are dealing with platform device anyway.
>>
>> I do not quite understand how declaring such MFD cell above would make sure
>> that the LPC probe is called before the IPMI device is enumerated...
>
> In fact it may be that it is not sufficient in this case because the
> ACPI core might enumerate child devices before the LPC driver even gets
> a chance to probe so you would need to add also scan handler to the
> child devices and mark them already enumerated or something like that.

Or extend the special I2C/SPI handling to them.

Thanks,
Rafael

[toc] | [prev] | [next] | [standalone]

#1667689

On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
> > In fact it may be that it is not sufficient in this case because the
> > ACPI core might enumerate child devices before the LPC driver even gets
> > a chance to probe so you would need to add also scan handler to the
> > child devices and mark them already enumerated or something like that.
> 
> Or extend the special I2C/SPI handling to them.

Sure but those have I2c/SpiSerialBus() resources which we can use to
identify them but for the ipmi thing there is nothing else than _HID so
we would need to keep a list of such devices in ACPI core.

[toc] | [prev] | [next] | [standalone]

#1667705

On Fri, Jun 16, 2017 at 2:00 PM, Mika Westerberg
<mika.westerberg@linux.intel.com> wrote:
> On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
>> > In fact it may be that it is not sufficient in this case because the
>> > ACPI core might enumerate child devices before the LPC driver even gets
>> > a chance to probe so you would need to add also scan handler to the
>> > child devices and mark them already enumerated or something like that.
>>
>> Or extend the special I2C/SPI handling to them.
>
> Sure but those have I2c/SpiSerialBus() resources which we can use to
> identify them but for the ipmi thing there is nothing else than _HID so
> we would need to keep a list of such devices in ACPI core.

OK, so adding a scan handler for that would be the way to go IMO.

[toc] | [prev] | [next] | [standalone]

#1668950 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Hi Rafael, Mika, Lorenzo

> -----Original Message-----
> From: rjwysocki@gmail.com [mailto:rjwysocki@gmail.com] On Behalf Of
> Rafael J. Wysocki
> Sent: 16 June 2017 13:23
> To: Mika Westerberg
> Cc: Rafael J. Wysocki; Gabriele Paoloni; Lorenzo Pieralisi; 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 Fri, Jun 16, 2017 at 2:00 PM, Mika Westerberg
> <mika.westerberg@linux.intel.com> wrote:
> > On Fri, Jun 16, 2017 at 01:24:32PM +0200, Rafael J. Wysocki wrote:
> >> > In fact it may be that it is not sufficient in this case because
> the
> >> > ACPI core might enumerate child devices before the LPC driver even
> gets
> >> > a chance to probe so you would need to add also scan handler to
> the
> >> > child devices and mark them already enumerated or something like
> that.
> >>
> >> Or extend the special I2C/SPI handling to them.
> >
> > Sure but those have I2c/SpiSerialBus() resources which we can use to
> > identify them but for the ipmi thing there is nothing else than _HID
> so
> > we would need to keep a list of such devices in ACPI core.
> 
> OK, so adding a scan handler for that would be the way to go IMO.

Many thanks for your response and your help here.

I guess that as conclusion with respect to the current v9 patchset we can
disregard the idea of MFD and modify the current v9 so that it doesn't
touch directly ACPI resources.
Instead as I proposed before we can have the scan handler to enumerate
the children devices and translate its addresses filling dev->resources[] and
at the same time we can modify acpi_default_enumeration to check
acpi_device_enumerated() before continuing with device enumeration...?

Do you think it as a viable solution?

Thanks
Gab

[toc] | [prev] | [next] | [standalone]

#1668959 — RE: [PATCH v9 5/7] ACPI: Translate the I/O range of non-MMIO devices before scanning

Hi Mika

> -----Original Message-----
> From: Mika Westerberg [mailto:mika.westerberg@linux.intel.com]
> Sent: 19 June 2017 11:02
> To: Gabriele Paoloni
> Cc: Rafael J. Wysocki; Lorenzo Pieralisi; 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 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> > Many thanks for your response and your help here.
> >
> > I guess that as conclusion with respect to the current v9 patchset we
> can
> > disregard the idea of MFD and modify the current v9 so that it
> doesn't
> > touch directly ACPI resources.
> > Instead as I proposed before we can have the scan handler to
> enumerate
> > the children devices and translate its addresses filling dev-
> >resources[] and
> > at the same time we can modify acpi_default_enumeration to check
> > acpi_device_enumerated() before continuing with device
> enumeration...?
> >
> > Do you think it as a viable solution?
> 
> No, I think MFD + scan handler inside the MFD driver is the way to go.
> We don't want to trash ACPI core with stuff that does not belong there
> IMHO.

Ok Many thanks I will investigate this direction 

> 
> Also you don't need to modify acpi_default_enumeration() because you
> can
> mark your device enumerated in the MFD driver. So all the dirty details
> will be in the MFD driver and not in ACPI core.

Ok got it :)

Cheers
Gab

[toc] | [prev] | [next] | [standalone]

#1668967

On Mon, Jun 19, 2017 at 09:50:49AM +0000, Gabriele Paoloni wrote:
> Many thanks for your response and your help here.
> 
> I guess that as conclusion with respect to the current v9 patchset we can
> disregard the idea of MFD and modify the current v9 so that it doesn't
> touch directly ACPI resources.
> Instead as I proposed before we can have the scan handler to enumerate
> the children devices and translate its addresses filling dev->resources[] and
> at the same time we can modify acpi_default_enumeration to check
> acpi_device_enumerated() before continuing with device enumeration...?
> 
> Do you think it as a viable solution?

No, I think MFD + scan handler inside the MFD driver is the way to go.
We don't want to trash ACPI core with stuff that does not belong there
IMHO.

Also you don't need to modify acpi_default_enumeration() because you can
mark your device enumerated in the MFD driver. So all the dirty details
will be in the MFD driver and not in ACPI core.

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web