Merge branch 'linus' into tracing/core

S: ask per mail for current address

S: ask per mail for current address

N: Nicolas Pitre

N: Nicolas Pitre

E: nico@cam.org

E: nico@fluxnic.net

D: StrongARM SA1100 support integrator & hacker

D: StrongARM SA1100 support integrator & hacker

D: Xscale PXA architecture

D: Xscale PXA architecture

D: unified SMC 91C9x/91C11x ethernet driver (smc91x)

D: unified SMC 91C9x/91C11x ethernet driver (smc91x)

	- info on the Block I/O (BIO) layer.

	- info on the Block I/O (BIO) layer.

blockdev/

blockdev/

	- info on block devices & drivers

	- info on block devices & drivers

btmrvl.txt

	- info on Marvell Bluetooth driver usage.

cachetlb.txt

cachetlb.txt

	- describes the cache/TLB flushing interfaces Linux uses.

	- describes the cache/TLB flushing interfaces Linux uses.

cdrom/

cdrom/

		from this part of the device tree.

		from this part of the device tree.

		Depends on CONFIG_HOTPLUG.

		Depends on CONFIG_HOTPLUG.

What:		/sys/bus/pci/devices/.../reset

Date:		July 2009

Contact:	Michael S. Tsirkin <mst@redhat.com>

Description:

		Some devices allow an individual function to be reset

		without affecting other functions in the same device.

		For devices that have this support, a file named reset

		will be present in sysfs.  Writing 1 to this file

		will perform reset.

What:		/sys/bus/pci/devices/.../vpd

What:		/sys/bus/pci/devices/.../vpd

Date:		February 2008

Date:		February 2008

Contact:	Ben Hutchings <bhutchings@solarflare.com>

Contact:	Ben Hutchings <bhutchings@solarflare.com>

	<year>2006-2008</year>

	<year>2006-2008</year>

	<holder>Hans-Jürgen Koch.</holder>

	<holder>Hans-Jürgen Koch.</holder>

</copyright>

</copyright>

<copyright>

	<year>2009</year>

	<holder>Red Hat Inc, Michael S. Tsirkin (mst@redhat.com)</holder>

</copyright>

<legalnotice>

<legalnotice>

<para>

<para>

</abstract>

</abstract>

<revhistory>

<revhistory>

	<revision>

	<revnumber>0.9</revnumber>

	<date>2009-07-16</date>

	<authorinitials>mst</authorinitials>

	<revremark>Added generic pci driver

		</revremark>

	</revision>

	<revision>

	<revision>

	<revnumber>0.8</revnumber>

	<revnumber>0.8</revnumber>

	<date>2008-12-24</date>

	<date>2008-12-24</date>

</chapter>

</chapter>

<chapter id="uio_pci_generic" xreflabel="Using Generic driver for PCI cards">

<?dbhtml filename="uio_pci_generic.html"?>

<title>Generic PCI UIO driver</title>

	<para>

	The generic driver is a kernel module named uio_pci_generic.

	It can work with any device compliant to PCI 2.3 (circa 2002) and

	any compliant PCI Express device. Using this, you only need to

        write the userspace driver, removing the need to write

        a hardware-specific kernel module.

	</para>

<sect1 id="uio_pci_generic_binding">

<title>Making the driver recognize the device</title>

	<para>

Since the driver does not declare any device ids, it will not get loaded

automatically and will not automatically bind to any devices, you must load it

and allocate id to the driver yourself. For example:

	<programlisting>

 modprobe uio_pci_generic

 echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id

	</programlisting>

	</para>

	<para>

If there already is a hardware specific kernel driver for your device, the

generic driver still won't bind to it, in this case if you want to use the

generic driver (why would you?) you'll have to manually unbind the hardware

specific driver and bind the generic driver, like this:

	<programlisting>

    echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind

    echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind

	</programlisting>

	</para>

	<para>

You can verify that the device has been bound to the driver

by looking for it in sysfs, for example like the following:

	<programlisting>

    ls -l /sys/bus/pci/devices/0000:00:19.0/driver

	</programlisting>

Which if successful should print

	<programlisting>

  .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic

	</programlisting>

Note that the generic driver will not bind to old PCI 2.2 devices.

If binding the device failed, run the following command:

	<programlisting>

  dmesg

	</programlisting>

and look in the output for failure reasons

	</para>

</sect1>

<sect1 id="uio_pci_generic_internals">

<title>Things to know about uio_pci_generic</title>

	<para>

Interrupts are handled using the Interrupt Disable bit in the PCI command

register and Interrupt Status bit in the PCI status register.  All devices

compliant to PCI 2.3 (circa 2002) and all compliant PCI Express devices should

support these bits.  uio_pci_generic detects this support, and won't bind to

devices which do not support the Interrupt Disable Bit in the command register.

	</para>

	<para>

On each interrupt, uio_pci_generic sets the Interrupt Disable bit.

This prevents the device from generating further interrupts

until the bit is cleared. The userspace driver should clear this

bit before blocking and waiting for more interrupts.

	</para>

</sect1>

<sect1 id="uio_pci_generic_userspace">

<title>Writing userspace driver using uio_pci_generic</title>

	<para>

Userspace driver can use pci sysfs interface, or the

libpci libray that wraps it, to talk to the device and to

re-enable interrupts by writing to the command register.

	</para>

</sect1>

<sect1 id="uio_pci_generic_example">

<title>Example code using uio_pci_generic</title>

	<para>

Here is some sample userspace driver code using uio_pci_generic:

<programlisting>

#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <errno.h>

int main()

{

	int uiofd;

	int configfd;

	int err;

	int i;

	unsigned icount;

	unsigned char command_high;

	uiofd = open("/dev/uio0", O_RDONLY);

	if (uiofd < 0) {

		perror("uio open:");

		return errno;

	}

	configfd = open("/sys/class/uio/uio0/device/config", O_RDWR);

	if (uiofd < 0) {

		perror("config open:");

		return errno;

	}

	/* Read and cache command value */

	err = pread(configfd, &command_high, 1, 5);

	if (err != 1) {

		perror("command config read:");

		return errno;

	}

	command_high &= ~0x4;

	for(i = 0;; ++i) {

		/* Print out a message, for debugging. */

		if (i == 0)

			fprintf(stderr, "Started uio test driver.\n");

		else

			fprintf(stderr, "Interrupts: %d\n", icount);

		/****************************************/

		/* Here we got an interrupt from the

		   device. Do something to it. */

		/****************************************/

		/* Re-enable interrupts. */

		err = pwrite(configfd, &command_high, 1, 5);

		if (err != 1) {

			perror("config write:");

			break;

		}

		/* Wait for next interrupt. */

		err = read(uiofd, &icount, 4);

		if (err != 4) {

			perror("uio read:");

			break;

		}

	}

	return errno;

}

</programlisting>

	</para>

</sect1>

</chapter>

<appendix id="app1">

<appendix id="app1">

<title>Further information</title>

<title>Further information</title>

<itemizedlist>

<itemizedlist>

                        February 2, 2006

                        February 2, 2006

                 Current document maintainer:

                 Current document maintainer:

             Linas Vepstas <linas@austin.ibm.com>

             Linas Vepstas <linasvepstas@gmail.com>

          updated by Richard Lary <rlary@us.ibm.com>

       and Mike Mason <mmlnx@us.ibm.com> on 27-Jul-2009

Many PCI bus controllers are able to detect a variety of hardware

Many PCI bus controllers are able to detect a variety of hardware

PCI errors on the bus, such as parity errors on the data and address

PCI errors on the bus, such as parity errors on the data and address

busses, as well as SERR and PERR errors.  Some of the more advanced

busses, as well as SERR and PERR errors.  Some of the more advanced

chipsets are able to deal with these errors; these include PCI-E chipsets,

chipsets are able to deal with these errors; these include PCI-E chipsets,

and the PCI-host bridges found on IBM Power4 and Power5-based pSeries

and the PCI-host bridges found on IBM Power4, Power5 and Power6-based

boxes. A typical action taken is to disconnect the affected device,

pSeries boxes. A typical action taken is to disconnect the affected device,

halting all I/O to it.  The goal of a disconnection is to avoid system

halting all I/O to it.  The goal of a disconnection is to avoid system

corruption; for example, to halt system memory corruption due to DMA's

corruption; for example, to halt system memory corruption due to DMA's

to "wild" addresses. Typically, a reconnection mechanism is also

to "wild" addresses. Typically, a reconnection mechanism is also

devices that have multiple device drivers associated with them.

devices that have multiple device drivers associated with them.

In the first stage, each driver is allowed to indicate what type

In the first stage, each driver is allowed to indicate what type

of reset it desires, the choices being a simple re-enabling of I/O

of reset it desires, the choices being a simple re-enabling of I/O

or requesting a hard reset (a full electrical #RST of the PCI card).

or requesting a slot reset.

If any driver requests a full reset, that is what will be done.

After a full reset and/or a re-enabling of I/O, all drivers are

If any driver requests a slot reset, that is what will be done.

After a reset and/or a re-enabling of I/O, all drivers are

again notified, so that they may then perform any device setup/config

again notified, so that they may then perform any device setup/config

that may be required.  After these have all completed, a final

that may be required.  After these have all completed, a final

"resume normal operations" event is sent out.

"resume normal operations" event is sent out.

is not implemented, the corresponding feature is considered unsupported.

is not implemented, the corresponding feature is considered unsupported.

For example, if mmio_enabled() and resume() aren't there, then it

For example, if mmio_enabled() and resume() aren't there, then it

is assumed that the driver is not doing any direct recovery and requires

is assumed that the driver is not doing any direct recovery and requires

a reset. If link_reset() is not implemented, the card is assumed as

a slot reset. If link_reset() is not implemented, the card is assumed to

not care about link resets. Typically a driver will want to know about

not care about link resets. Typically a driver will want to know about

a slot_reset().

a slot_reset().

STEP 0: Error Event

STEP 0: Error Event

-------------------

-------------------

PCI bus error is detect by the PCI hardware.  On powerpc, the slot

A PCI bus error is detected by the PCI hardware.  On powerpc, the slot

is isolated, in that all I/O is blocked: all reads return 0xffffffff,

is isolated, in that all I/O is blocked: all reads return 0xffffffff,

all writes are ignored.

all writes are ignored.

		  a chance to extract some diagnostic information (see

		  a chance to extract some diagnostic information (see

		  mmio_enable, below).

		  mmio_enable, below).

		- PCI_ERS_RESULT_NEED_RESET:

		- PCI_ERS_RESULT_NEED_RESET:

		  Driver returns this if it can't recover without a hard

		  Driver returns this if it can't recover without a

		  slot reset.

		  slot reset.

		- PCI_ERS_RESULT_DISCONNECT:

		- PCI_ERS_RESULT_DISCONNECT:

		  Driver returns this if it doesn't want to recover at all.

		  Driver returns this if it doesn't want to recover at all.

>>> The current powerpc implementation doesn't much care if the device

>>> The current powerpc implementation doesn't much care if the device

>>> attempts I/O at this point, or not.  I/O's will fail, returning

>>> attempts I/O at this point, or not.  I/O's will fail, returning

>>> a value of 0xff on read, and writes will be dropped. If the device

>>> a value of 0xff on read, and writes will be dropped. If more than

>>> driver attempts more than 10K I/O's to a frozen adapter, it will

>>> EEH_MAX_FAILS I/O's are attempted to a frozen adapter, EEH

>>> assume that the device driver has gone into an infinite loop, and

>>> assumes that the device driver has gone into an infinite loop

>>> it will panic the kernel. There doesn't seem to be any other

>>> and prints an error to syslog.  A reboot is then required to 

>>> way of stopping a device driver that insists on spinning on I/O.

>>> get the device working again.

STEP 2: MMIO Enabled

STEP 2: MMIO Enabled

-------------------

-------------------

device drivers.

device drivers.

This is the "early recovery" call. IOs are allowed again, but DMA is

This is the "early recovery" call. IOs are allowed again, but DMA is

not (hrm... to be discussed, I prefer not), with some restrictions. This

not, with some restrictions. This is NOT a callback for the driver to

is NOT a callback for the driver to start operations again, only to

start operations again, only to peek/poke at the device, extract diagnostic

peek/poke at the device, extract diagnostic information, if any, and

information, if any, and eventually do things like trigger a device local

eventually do things like trigger a device local reset or some such,

reset or some such, but not restart operations. This callback is made if

but not restart operations. This is callback is made if all drivers on

all drivers on a segment agree that they can try to recover and if no automatic

a segment agree that they can try to recover and if no automatic link reset

link reset was performed by the HW. If the platform can't just re-enable IOs

was performed by the HW. If the platform can't just re-enable IOs without

without a slot reset or a link reset, it will not call this callback, and

a slot reset or a link reset, it wont call this callback, and instead

instead will have gone directly to STEP 3 (Link Reset) or STEP 4 (Slot Reset)

will have gone directly to STEP 3 (Link Reset) or STEP 4 (Slot Reset)

>>> The following is proposed; no platform implements this yet:

>>> The following is proposed; no platform implements this yet:

>>> Proposal: All I/O's should be done _synchronously_ from within

>>> Proposal: All I/O's should be done _synchronously_ from within

If any driver returned PCI_ERS_RESULT_NEED_RESET, then the platform

If any driver returned PCI_ERS_RESULT_NEED_RESET, then the platform

proceeds to STEP 4 (Slot Reset)

proceeds to STEP 4 (Slot Reset)

>>> The current powerpc implementation does not implement this callback.

STEP 3: Link Reset

STEP 3: Link Reset

------------------

------------------

The platform resets the link, and then calls the link_reset() callback

The platform resets the link, and then calls the link_reset() callback

>>> The current powerpc implementation does not implement this callback.

>>> The current powerpc implementation does not implement this callback.

STEP 4: Slot Reset

STEP 4: Slot Reset

------------------

------------------

The platform performs a soft or hard reset of the device, and then

calls the slot_reset() callback.

A soft reset consists of asserting the adapter #RST line and then

In response to a return value of PCI_ERS_RESULT_NEED_RESET, the

the platform will peform a slot reset on the requesting PCI device(s). 

The actual steps taken by a platform to perform a slot reset

will be platform-dependent. Upon completion of slot reset, the

platform will call the device slot_reset() callback.

Powerpc platforms implement two levels of slot reset:

soft reset(default) and fundamental(optional) reset.

Powerpc soft reset consists of asserting the adapter #RST line and then

restoring the PCI BAR's and PCI configuration header to a state

restoring the PCI BAR's and PCI configuration header to a state

that is equivalent to what it would be after a fresh system

that is equivalent to what it would be after a fresh system

power-on followed by power-on BIOS/system firmware initialization.

power-on followed by power-on BIOS/system firmware initialization.

Soft reset is also known as hot-reset.

Powerpc fundamental reset is supported by PCI Express cards only

and results in device's state machines, hardware logic, port states and

configuration registers to initialize to their default conditions.

For most PCI devices, a soft reset will be sufficient for recovery.

Optional fundamental reset is provided to support a limited number

of PCI Express PCI devices  for which a soft reset is not sufficient

for recovery.

If the platform supports PCI hotplug, then the reset might be

If the platform supports PCI hotplug, then the reset might be

performed by toggling the slot electrical power off/on.

performed by toggling the slot electrical power off/on.

This call gives drivers the chance to re-initialize the hardware

This call gives drivers the chance to re-initialize the hardware

(re-download firmware, etc.).  At this point, the driver may assume

(re-download firmware, etc.).  At this point, the driver may assume

that he card is in a fresh state and is fully functional. In

that the card is in a fresh state and is fully functional. The slot

particular, interrupt generation should work normally.

is unfrozen and the driver has full access to PCI config space,

memory mapped I/O space and DMA. Interrupts (Legacy, MSI, or MSI-X)

will also be available.

Drivers should not yet restart normal I/O processing operations

Drivers should not restart normal I/O processing operations

at this point.  If all device drivers report success on this

at this point.  If all device drivers report success on this

callback, the platform will call resume() to complete the sequence,

callback, the platform will call resume() to complete the sequence,

and let the driver restart normal I/O processing.

and let the driver restart normal I/O processing.

		- PCI_ERS_RESULT_DISCONNECT

		- PCI_ERS_RESULT_DISCONNECT

		Same as above.

		Same as above.

Drivers for PCI Express cards that require a fundamental reset must

set the needs_freset bit in the pci_dev structure in their probe function.  

For example, the QLogic qla2xxx driver sets the needs_freset bit for certain

PCI card types:

+	/* Set EEH reset type to fundamental if required by hba  */

+	if (IS_QLA24XX(ha) || IS_QLA25XX(ha) || IS_QLA81XX(ha))

+		pdev->needs_freset = 1;

+

Platform proceeds either to STEP 5 (Resume Operations) or STEP 6 (Permanent

Platform proceeds either to STEP 5 (Resume Operations) or STEP 6 (Permanent

Failure).

Failure).

>>> The current powerpc implementation does not currently try a

>>> The current powerpc implementation does not try a power-cycle

>>> power-cycle reset if the driver returned PCI_ERS_RESULT_DISCONNECT.

>>> reset if the driver returned PCI_ERS_RESULT_DISCONNECT.

>>> However, it probably should.

>>> However, it probably should.

Conclusion; General Remarks

Conclusion; General Remarks

---------------------------

---------------------------

The way those callbacks are called is platform policy. A platform with

The way the callbacks are called is platform policy. A platform with

no slot reset capability may want to just "ignore" drivers that can't

no slot reset capability may want to just "ignore" drivers that can't

recover (disconnect them) and try to let other cards on the same segment

recover (disconnect them) and try to let other cards on the same segment

recover. Keep in mind that in most real life cases, though, there will

recover. Keep in mind that in most real life cases, though, there will

 - There is no guarantee that interrupt delivery can proceed from any

 - There is no guarantee that interrupt delivery can proceed from any

device on the segment starting from the error detection and until the

device on the segment starting from the error detection and until the

resume callback is sent, at which point interrupts are expected to be

slot_reset callback is called, at which point interrupts are expected

fully operational.

to be fully operational.

 - There is no guarantee that interrupt delivery is stopped, that is,

 - There is no guarantee that interrupt delivery is stopped, that is,

a driver that gets an interrupt after detecting an error, or that detects

a driver that gets an interrupt after detecting an error, or that detects

>>> Implementation details for the powerpc platform are discussed in

>>> Implementation details for the powerpc platform are discussed in

>>> the file Documentation/powerpc/eeh-pci-error-recovery.txt

>>> the file Documentation/powerpc/eeh-pci-error-recovery.txt

>>> As of this writing, there are six device drivers with patches

>>> As of this writing, there is a growing list of device drivers with

>>> implementing error recovery. Not all of these patches are in

>>> patches implementing error recovery. Not all of these patches are in

>>> mainline yet. These may be used as "examples":

>>> mainline yet. These may be used as "examples":

>>>

>>>

>>> drivers/scsi/ipr.c

>>> drivers/scsi/ipr

>>> drivers/scsi/sym53cxx_2

>>> drivers/scsi/sym53c8xx_2

>>> drivers/scsi/qla2xxx

>>> drivers/scsi/lpfc

>>> drivers/next/bnx2.c

>>> drivers/next/e100.c

>>> drivers/next/e100.c

>>> drivers/net/e1000

>>> drivers/net/e1000

>>> drivers/net/e1000e

>>> drivers/net/ixgb

>>> drivers/net/ixgb

>>> drivers/net/ixgbe

>>> drivers/net/cxgb3

>>> drivers/net/s2io.c

>>> drivers/net/s2io.c

>>> drivers/net/qlge

The End

The End

-------

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