LinuxLists.cc - [PATCH v4 00/12] Include linux PCI docs into Sphinx TOC tree

2019-05-12 12:53:39

Subject: [PATCH v4 00/12] Include linux PCI docs into Sphinx TOC tree

Hi all,

The kernel now uses Sphinx to generate intelligent and beautiful documentation
from reStructuredText files. I converted most of the Linux PCI docs to rst
format in this serias.

For you to preview, please visit below url:
http://www.bytemem.com:8080/kernel-doc/PCI/index.html

Thank you!

v2: trivial style update.
v3: update titles. (Bjorn Helgaas)
v4: fix comments from Mauro Carvalho Chehab

Changbin Du (12):
Documentation: add Linux PCI to Sphinx TOC tree
Documentation: PCI: convert pci.txt to reST
Documentation: PCI: convert PCIEBUS-HOWTO.txt to reST
Documentation: PCI: convert pci-iov-howto.txt to reST
Documentation: PCI: convert MSI-HOWTO.txt to reST
Documentation: PCI: convert acpi-info.txt to reST
Documentation: PCI: convert pci-error-recovery.txt to reST
Documentation: PCI: convert pcieaer-howto.txt to reST
Documentation: PCI: convert endpoint/pci-endpoint.txt to reST
Documentation: PCI: convert endpoint/pci-endpoint-cfs.txt to reST
Documentation: PCI: convert endpoint/pci-test-function.txt to reST
Documentation: PCI: convert endpoint/pci-test-howto.txt to reST

.../PCI/{acpi-info.txt => acpi-info.rst} | 15 +-
Documentation/PCI/endpoint/index.rst | 13 +
...-endpoint-cfs.txt => pci-endpoint-cfs.rst} | 99 ++---
.../{pci-endpoint.txt => pci-endpoint.rst} | 96 +++--
...est-function.txt => pci-test-function.rst} | 34 +-
...{pci-test-howto.txt => pci-test-howto.rst} | 81 ++--
Documentation/PCI/index.rst | 18 +
.../PCI/{MSI-HOWTO.txt => msi-howto.rst} | 85 +++--
...or-recovery.txt => pci-error-recovery.rst} | 287 +++++++-------
.../{pci-iov-howto.txt => pci-iov-howto.rst} | 161 ++++----
Documentation/PCI/{pci.txt => pci.rst} | 356 ++++++++----------
.../{pcieaer-howto.txt => pcieaer-howto.rst} | 156 +++++---
.../{PCIEBUS-HOWTO.txt => picebus-howto.rst} | 140 ++++---
Documentation/index.rst | 1 +
MAINTAINERS | 2 +-
include/linux/mod_devicetable.h | 19 +
include/linux/pci.h | 37 ++
17 files changed, 912 insertions(+), 688 deletions(-)
rename Documentation/PCI/{acpi-info.txt => acpi-info.rst} (96%)
create mode 100644 Documentation/PCI/endpoint/index.rst
rename Documentation/PCI/endpoint/{pci-endpoint-cfs.txt => pci-endpoint-cfs.rst} (64%)
rename Documentation/PCI/endpoint/{pci-endpoint.txt => pci-endpoint.rst} (82%)
rename Documentation/PCI/endpoint/{pci-test-function.txt => pci-test-function.rst} (84%)
rename Documentation/PCI/endpoint/{pci-test-howto.txt => pci-test-howto.rst} (78%)
create mode 100644 Documentation/PCI/index.rst
rename Documentation/PCI/{MSI-HOWTO.txt => msi-howto.rst} (88%)
rename Documentation/PCI/{pci-error-recovery.txt => pci-error-recovery.rst} (67%)
rename Documentation/PCI/{pci-iov-howto.txt => pci-iov-howto.rst} (63%)
rename Documentation/PCI/{pci.txt => pci.rst} (68%)
rename Documentation/PCI/{pcieaer-howto.txt => pcieaer-howto.rst} (72%)
rename Documentation/PCI/{PCIEBUS-HOWTO.txt => picebus-howto.rst} (70%)

--
2.20.1

2019-05-12 12:53:39

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 10/12] Documentation: PCI: convert endpoint/pci-endpoint-cfs.txt to reST

2019-05-12 12:53:39

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 02/12] Documentation: PCI: convert pci.txt to reST

This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

The description about struct pci_driver and struct pci_device_id are moved
into in-source comments.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
---
Documentation/PCI/index.rst | 2 +
Documentation/PCI/{pci.txt => pci.rst} | 356 +++++++++++--------------
include/linux/mod_devicetable.h | 19 ++
include/linux/pci.h | 37 +++
4 files changed, 207 insertions(+), 207 deletions(-)
rename Documentation/PCI/{pci.txt => pci.rst} (68%)

diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
index c2f8728d11cf..7babf43709b0 100644
--- a/Documentation/PCI/index.rst
+++ b/Documentation/PCI/index.rst
@@ -7,3 +7,5 @@ Linux PCI Bus Subsystem
.. toctree::
:maxdepth: 2
:numbered:
+
+ pci
diff --git a/Documentation/PCI/pci.txt b/Documentation/PCI/pci.rst
similarity index 68%
rename from Documentation/PCI/pci.txt
rename to Documentation/PCI/pci.rst
index badb26ac33dc..6864f9a70f5f 100644
--- a/Documentation/PCI/pci.txt
+++ b/Documentation/PCI/pci.rst
@@ -1,10 +1,12 @@
+.. SPDX-License-Identifier: GPL-2.0

- How To Write Linux PCI Drivers
+==============================
+How To Write Linux PCI Drivers
+==============================

- by Martin Mares <[email protected]> on 07-Feb-2000
- updated by Grant Grundler <[email protected]> on 23-Dec-2006
+:Authors: - Martin Mares <[email protected]>
+ - Grant Grundler <[email protected]>

-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The world of PCI is vast and full of (mostly unpleasant) surprises.
Since each CPU architecture implements different chip-sets and PCI devices
have different requirements (erm, "features"), the result is the PCI support
@@ -15,8 +17,7 @@ PCI device drivers.
A more complete resource is the third edition of "Linux Device Drivers"
by Jonathan Corbet, Alessandro Rubini, and Greg Kroah-Hartman.
LDD3 is available for free (under Creative Commons License) from:
-
- http://lwn.net/Kernel/LDD3/
+http://lwn.net/Kernel/LDD3/.

However, keep in mind that all documents are subject to "bit rot".
Refer to the source code if things are not working as described here.
@@ -25,9 +26,8 @@ Please send questions/comments/patches about Linux PCI API to the
"Linux PCI" <[email protected]> mailing list.

-
-0. Structure of PCI drivers
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Structure of PCI drivers
+========================
PCI drivers "discover" PCI devices in a system via pci_register_driver().
Actually, it's the other way around. When the PCI generic code discovers
a new device, the driver with a matching "description" will be notified.
@@ -42,24 +42,25 @@ pointers and thus dictates the high level structure of a driver.
Once the driver knows about a PCI device and takes ownership, the
driver generally needs to perform the following initialization:

- Enable the device
- Request MMIO/IOP resources
- Set the DMA mask size (for both coherent and streaming DMA)
- Allocate and initialize shared control data (pci_allocate_coherent())
- Access device configuration space (if needed)
- Register IRQ handler (request_irq())
- Initialize non-PCI (i.e. LAN/SCSI/etc parts of the chip)
- Enable DMA/processing engines
+ - Enable the device
+ - Request MMIO/IOP resources
+ - Set the DMA mask size (for both coherent and streaming DMA)
+ - Allocate and initialize shared control data (pci_allocate_coherent())
+ - Access device configuration space (if needed)
+ - Register IRQ handler (request_irq())
+ - Initialize non-PCI (i.e. LAN/SCSI/etc parts of the chip)
+ - Enable DMA/processing engines

When done using the device, and perhaps the module needs to be unloaded,
the driver needs to take the follow steps:
- Disable the device from generating IRQs
- Release the IRQ (free_irq())
- Stop all DMA activity
- Release DMA buffers (both streaming and coherent)
- Unregister from other subsystems (e.g. scsi or netdev)
- Release MMIO/IOP resources
- Disable the device
+
+ - Disable the device from generating IRQs
+ - Release the IRQ (free_irq())
+ - Stop all DMA activity
+ - Release DMA buffers (both streaming and coherent)
+ - Unregister from other subsystems (e.g. scsi or netdev)
+ - Release MMIO/IOP resources
+ - Disable the device

Most of these topics are covered in the following sections.
For the rest look at LDD3 or <linux/pci.h> .
@@ -70,99 +71,38 @@ completely empty or just returning an appropriate error codes to avoid
lots of ifdefs in the drivers.

+pci_register_driver() call
+==========================

-1. pci_register_driver() call
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-PCI device drivers call pci_register_driver() during their
+PCI device drivers call ``pci_register_driver()`` during their
initialization with a pointer to a structure describing the driver
-(struct pci_driver):
-
- field name Description
- ---------- ------------------------------------------------------
- id_table Pointer to table of device ID's the driver is
- interested in. Most drivers should export this
- table using MODULE_DEVICE_TABLE(pci,...).
-
- probe This probing function gets called (during execution
- of pci_register_driver() for already existing
- devices or later if a new device gets inserted) for
- all PCI devices which match the ID table and are not
- "owned" by the other drivers yet. This function gets
- passed a "struct pci_dev *" for each device whose
- entry in the ID table matches the device. The probe
- function returns zero when the driver chooses to
- take "ownership" of the device or an error code
- (negative number) otherwise.
- The probe function always gets called from process
- context, so it can sleep.
-
- remove The remove() function gets called whenever a device
- being handled by this driver is removed (either during
- deregistration of the driver or when it's manually
- pulled out of a hot-pluggable slot).
- The remove function always gets called from process
- context, so it can sleep.
-
- suspend Put device into low power state.
- suspend_late Put device into low power state.
-
- resume_early Wake device from low power state.
- resume Wake device from low power state.
-
- (Please see Documentation/power/pci.txt for descriptions
- of PCI Power Management and the related functions.)
-
- shutdown Hook into reboot_notifier_list (kernel/sys.c).
- Intended to stop any idling DMA operations.
- Useful for enabling wake-on-lan (NIC) or changing
- the power state of a device before reboot.
- e.g. drivers/net/e100.c.
-
- err_handler See Documentation/PCI/pci-error-recovery.txt
-
-
-The ID table is an array of struct pci_device_id entries ending with an
-all-zero entry. Definitions with static const are generally preferred.
-
-Each entry consists of:
-
- vendor,device Vendor and device ID to match (or PCI_ANY_ID)
+(``struct pci_driver``):

- subvendor, Subsystem vendor and device ID to match (or PCI_ANY_ID)
- subdevice,
+.. kernel-doc:: include/linux/pci.h
+ :functions: pci_driver

- class Device class, subclass, and "interface" to match.
- See Appendix D of the PCI Local Bus Spec or
- include/linux/pci_ids.h for a full list of classes.
- Most drivers do not need to specify class/class_mask
- as vendor/device is normally sufficient.
-
- class_mask limit which sub-fields of the class field are compared.
- See drivers/scsi/sym53c8xx_2/ for example of usage.
-
- driver_data Data private to the driver.
- Most drivers don't need to use driver_data field.
- Best practice is to use driver_data as an index
- into a static list of equivalent device types,
- instead of using it as a pointer.
+The ID table is an array of ``struct pci_device_id`` entries ending with an
+all-zero entry. Definitions with static const are generally preferred.

+.. kernel-doc:: include/linux/mod_devicetable.h
+ :functions: pci_device_id

-Most drivers only need PCI_DEVICE() or PCI_DEVICE_CLASS() to set up
+Most drivers only need ``PCI_DEVICE()`` or ``PCI_DEVICE_CLASS()`` to set up
a pci_device_id table.

New PCI IDs may be added to a device driver pci_ids table at runtime
-as shown below:
+as shown below::

-echo "vendor device subvendor subdevice class class_mask driver_data" > \
-/sys/bus/pci/drivers/{driver}/new_id
+ echo "vendor device subvendor subdevice class class_mask driver_data" > \
+ /sys/bus/pci/drivers/{driver}/new_id

All fields are passed in as hexadecimal values (no leading 0x).
The vendor and device fields are mandatory, the others are optional. Users
need pass only as many optional fields as necessary:
- o subvendor and subdevice fields default to PCI_ANY_ID (FFFFFFFF)
- o class and classmask fields default to 0
- o driver_data defaults to 0UL.
+
+ - subvendor and subdevice fields default to PCI_ANY_ID (FFFFFFFF)
+ - class and classmask fields default to 0
+ - driver_data defaults to 0UL.

Note that driver_data must match the value used by any of the pci_device_id
entries defined in the driver. This makes the driver_data field mandatory
@@ -175,29 +115,31 @@ When the driver exits, it just calls pci_unregister_driver() and the PCI layer
automatically calls the remove hook for all devices handled by the driver.

-1.1 "Attributes" for driver functions/data
+"Attributes" for driver functions/data
+--------------------------------------

Please mark the initialization and cleanup functions where appropriate
(the corresponding macros are defined in <linux/init.h>):

+ ====== =================================================
__init Initialization code. Thrown away after the driver
initializes.
__exit Exit code. Ignored for non-modular drivers.
+ ====== =================================================

Tips on when/where to use the above attributes:
- o The module_init()/module_exit() functions (and all
+ - The module_init()/module_exit() functions (and all
initialization functions called _only_ from these)
should be marked __init/__exit.

- o Do not mark the struct pci_driver.
+ - Do not mark the struct pci_driver.

- o Do NOT mark a function if you are not sure which mark to use.
+ - Do NOT mark a function if you are not sure which mark to use.
Better to not mark the function than mark the function wrong.

-
-2. How to find PCI devices manually
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+How to find PCI devices manually
+================================

PCI drivers should have a really good reason for not using the
pci_register_driver() interface to search for PCI devices.
@@ -207,17 +149,17 @@ E.g. combined serial/parallel port/floppy controller.

A manual search may be performed using the following constructs:

-Searching by vendor and device ID:
+Searching by vendor and device ID::

struct pci_dev *dev = NULL;
while (dev = pci_get_device(VENDOR_ID, DEVICE_ID, dev))
configure_device(dev);

-Searching by class ID (iterate in a similar way):
+Searching by class ID (iterate in a similar way)::

pci_get_class(CLASS_ID, dev)

-Searching by both vendor/device and subsystem vendor/device ID:
+Searching by both vendor/device and subsystem vendor/device ID::

pci_get_subsys(VENDOR_ID,DEVICE_ID, SUBSYS_VENDOR_ID, SUBSYS_DEVICE_ID, dev).

@@ -230,21 +172,20 @@ the pci_dev that they return. You must eventually (possibly at module unload)
decrement the reference count on these devices by calling pci_dev_put().

-
-3. Device Initialization Steps
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Device Initialization Steps
+===========================

As noted in the introduction, most PCI drivers need the following steps
for device initialization:

- Enable the device
- Request MMIO/IOP resources
- Set the DMA mask size (for both coherent and streaming DMA)
- Allocate and initialize shared control data (pci_allocate_coherent())
- Access device configuration space (if needed)
- Register IRQ handler (request_irq())
- Initialize non-PCI (i.e. LAN/SCSI/etc parts of the chip)
- Enable DMA/processing engines.
+ - Enable the device
+ - Request MMIO/IOP resources
+ - Set the DMA mask size (for both coherent and streaming DMA)
+ - Allocate and initialize shared control data (pci_allocate_coherent())
+ - Access device configuration space (if needed)
+ - Register IRQ handler (request_irq())
+ - Initialize non-PCI (i.e. LAN/SCSI/etc parts of the chip)
+ - Enable DMA/processing engines.

The driver can access PCI config space registers at any time.
(Well, almost. When running BIST, config space can go away...but
@@ -252,26 +193,29 @@ that will just result in a PCI Bus Master Abort and config reads
will return garbage).

-3.1 Enable the PCI device
-~~~~~~~~~~~~~~~~~~~~~~~~~
+Enable the PCI device
+---------------------
Before touching any device registers, the driver needs to enable
the PCI device by calling pci_enable_device(). This will:
- o wake up the device if it was in suspended state,
- o allocate I/O and memory regions of the device (if BIOS did not),
- o allocate an IRQ (if BIOS did not).

-NOTE: pci_enable_device() can fail! Check the return value.
+ - wake up the device if it was in suspended state,
+ - allocate I/O and memory regions of the device (if BIOS did not),
+ - allocate an IRQ (if BIOS did not).

-[ OS BUG: we don't check resource allocations before enabling those
- resources. The sequence would make more sense if we called
- pci_request_resources() before calling pci_enable_device().
- Currently, the device drivers can't detect the bug when when two
- devices have been allocated the same range. This is not a common
- problem and unlikely to get fixed soon.
+.. note::
+ pci_enable_device() can fail! Check the return value.
+
+.. warning::
+ OS BUG: we don't check resource allocations before enabling those
+ resources. The sequence would make more sense if we called
+ pci_request_resources() before calling pci_enable_device().
+ Currently, the device drivers can't detect the bug when when two
+ devices have been allocated the same range. This is not a common
+ problem and unlikely to get fixed soon.
+
+ This has been discussed before but not changed as of 2.6.19:
+ http://lkml.org/lkml/2006/3/2/194

- This has been discussed before but not changed as of 2.6.19:
- http://lkml.org/lkml/2006/3/2/194
-]

pci_set_master() will enable DMA by setting the bus master bit
in the PCI_COMMAND register. It also fixes the latency timer value if
@@ -288,8 +232,8 @@ pci_try_set_mwi() to have the system do its best effort at enabling
Mem-Wr-Inval.

-3.2 Request MMIO/IOP resources
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Request MMIO/IOP resources
+--------------------------
Memory (MMIO), and I/O port addresses should NOT be read directly
from the PCI device config space. Use the values in the pci_dev structure
as the PCI "bus address" might have been remapped to a "host physical"
@@ -304,9 +248,10 @@ Conversely, drivers should call pci_release_region() AFTER
calling pci_disable_device().
The idea is to prevent two devices colliding on the same address range.

-[ See OS BUG comment above. Currently (2.6.19), The driver can only
- determine MMIO and IO Port resource availability _after_ calling
- pci_enable_device(). ]
+.. tip::
+ See OS BUG comment above. Currently (2.6.19), The driver can only
+ determine MMIO and IO Port resource availability _after_ calling
+ pci_enable_device().

Generic flavors of pci_request_region() are request_mem_region()
(for MMIO ranges) and request_region() (for IO Port ranges).
@@ -316,12 +261,13 @@ BARs.
Also see pci_request_selected_regions() below.

-3.3 Set the DMA mask size
-~~~~~~~~~~~~~~~~~~~~~~~~~
-[ If anything below doesn't make sense, please refer to
- Documentation/DMA-API.txt. This section is just a reminder that
- drivers need to indicate DMA capabilities of the device and is not
- an authoritative source for DMA interfaces. ]
+Set the DMA mask size
+---------------------
+.. note::
+ If anything below doesn't make sense, please refer to
+ Documentation/DMA-API.txt. This section is just a reminder that
+ drivers need to indicate DMA capabilities of the device and is not
+ an authoritative source for DMA interfaces.

While all drivers should explicitly indicate the DMA capability
(e.g. 32 or 64 bit) of the PCI bus master, devices with more than
@@ -342,23 +288,23 @@ Many 64-bit "PCI" devices (before PCI-X) and some PCI-X devices are
("consistent") data.

-3.4 Setup shared control data
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Setup shared control data
+-------------------------
Once the DMA masks are set, the driver can allocate "consistent" (a.k.a. shared)
memory. See Documentation/DMA-API.txt for a full description of
the DMA APIs. This section is just a reminder that it needs to be done
before enabling DMA on the device.

-3.5 Initialize device registers
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Initialize device registers
+---------------------------
Some drivers will need specific "capability" fields programmed
or other "vendor specific" register initialized or reset.
E.g. clearing pending interrupts.

-3.6 Register IRQ handler
-~~~~~~~~~~~~~~~~~~~~~~~~
+Register IRQ handler
+--------------------
While calling request_irq() is the last step described here,
this is often just another intermediate step to initialize a device.
This step can often be deferred until the device is opened for use.
@@ -396,6 +342,7 @@ and msix_enabled flags in the pci_dev structure after calling
pci_alloc_irq_vectors.

There are (at least) two really good reasons for using MSI:
+
1) MSI is an exclusive interrupt vector by definition.
This means the interrupt handler doesn't have to verify
its device caused the interrupt.
@@ -410,24 +357,23 @@ See drivers/infiniband/hw/mthca/ or drivers/net/tg3.c for examples
of MSI/MSI-X usage.

-
-4. PCI device shutdown
-~~~~~~~~~~~~~~~~~~~~~~~
+PCI device shutdown
+===================

When a PCI device driver is being unloaded, most of the following
steps need to be performed:

- Disable the device from generating IRQs
- Release the IRQ (free_irq())
- Stop all DMA activity
- Release DMA buffers (both streaming and consistent)
- Unregister from other subsystems (e.g. scsi or netdev)
- Disable device from responding to MMIO/IO Port addresses
- Release MMIO/IO Port resource(s)
+ - Disable the device from generating IRQs
+ - Release the IRQ (free_irq())
+ - Stop all DMA activity
+ - Release DMA buffers (both streaming and consistent)
+ - Unregister from other subsystems (e.g. scsi or netdev)
+ - Disable device from responding to MMIO/IO Port addresses
+ - Release MMIO/IO Port resource(s)

-4.1 Stop IRQs on the device
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Stop IRQs on the device
+-----------------------
How to do this is chip/device specific. If it's not done, it opens
the possibility of a "screaming interrupt" if (and only if)
the IRQ is shared with another device.
@@ -446,16 +392,16 @@ MSI and MSI-X are defined to be exclusive interrupts and thus
are not susceptible to the "screaming interrupt" problem.

-4.2 Release the IRQ
-~~~~~~~~~~~~~~~~~~~
+Release the IRQ
+---------------
Once the device is quiesced (no more IRQs), one can call free_irq().
This function will return control once any pending IRQs are handled,
"unhook" the drivers IRQ handler from that IRQ, and finally release
the IRQ if no one else is using it.

-4.3 Stop all DMA activity
-~~~~~~~~~~~~~~~~~~~~~~~~~
+Stop all DMA activity
+---------------------
It's extremely important to stop all DMA operations BEFORE attempting
to deallocate DMA control data. Failure to do so can result in memory
corruption, hangs, and on some chip-sets a hard crash.
@@ -467,8 +413,8 @@ While this step sounds obvious and trivial, several "mature" drivers
didn't get this step right in the past.

-4.4 Release DMA buffers
-~~~~~~~~~~~~~~~~~~~~~~~
+Release DMA buffers
+-------------------
Once DMA is stopped, clean up streaming DMA first.
I.e. unmap data buffers and return buffers to "upstream"
owners if there is one.
@@ -478,8 +424,8 @@ Then clean up "consistent" buffers which contain the control data.
See Documentation/DMA-API.txt for details on unmapping interfaces.

-4.5 Unregister from other subsystems
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Unregister from other subsystems
+--------------------------------
Most low level PCI device drivers support some other subsystem
like USB, ALSA, SCSI, NetDev, Infiniband, etc. Make sure your
driver isn't losing resources from that other subsystem.
@@ -487,31 +433,30 @@ If this happens, typically the symptom is an Oops (panic) when
the subsystem attempts to call into a driver that has been unloaded.

-4.6 Disable Device from responding to MMIO/IO Port addresses
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Disable Device from responding to MMIO/IO Port addresses
+--------------------------------------------------------
io_unmap() MMIO or IO Port resources and then call pci_disable_device().
This is the symmetric opposite of pci_enable_device().
Do not access device registers after calling pci_disable_device().

-4.7 Release MMIO/IO Port Resource(s)
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Release MMIO/IO Port Resource(s)
+--------------------------------
Call pci_release_region() to mark the MMIO or IO Port range as available.
Failure to do so usually results in the inability to reload the driver.

+How to access PCI config space
+==============================

-5. How to access PCI config space
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-You can use pci_(read|write)_config_(byte|word|dword) to access the config
-space of a device represented by struct pci_dev *. All these functions return 0
-when successful or an error code (PCIBIOS_...) which can be translated to a text
-string by pcibios_strerror. Most drivers expect that accesses to valid PCI
+You can use `pci_(read|write)_config_(byte|word|dword)` to access the config
+space of a device represented by `struct pci_dev *`. All these functions return
+0 when successful or an error code (`PCIBIOS_...`) which can be translated to a
+text string by pcibios_strerror. Most drivers expect that accesses to valid PCI
devices don't fail.

If you don't have a struct pci_dev available, you can call
-pci_bus_(read|write)_config_(byte|word|dword) to access a given device
+`pci_bus_(read|write)_config_(byte|word|dword)` to access a given device
and function on that bus.

If you access fields in the standard portion of the config header, please
@@ -522,10 +467,10 @@ pci_find_capability() for the particular capability and it will find the
corresponding register block for you.

+Other interesting functions
+===========================

-6. Other interesting functions
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
+============================= ================================================
pci_get_domain_bus_and_slot() Find pci_dev corresponding to given domain,
bus and slot and number. If the device is
found, its reference count is increased.
@@ -539,11 +484,11 @@ pci_set_drvdata() Set private driver data pointer for a pci_dev
pci_get_drvdata() Return private driver data pointer for a pci_dev
pci_set_mwi() Enable Memory-Write-Invalidate transactions.
pci_clear_mwi() Disable Memory-Write-Invalidate transactions.
+============================= ================================================

-
-7. Miscellaneous hints
-~~~~~~~~~~~~~~~~~~~~~~
+Miscellaneous hints
+===================

When displaying PCI device names to the user (for example when a driver wants
to tell the user what card has it found), please use pci_name(pci_dev).
@@ -559,9 +504,8 @@ on the bus need to be capable of doing it, so this is something which needs
to be handled by platform and generic code, not individual drivers.

-
-8. Vendor and device identifications
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Vendor and device identifications
+=================================

Do not add new device or vendor IDs to include/linux/pci_ids.h unless they
are shared across multiple drivers. You can add private definitions in
@@ -575,28 +519,27 @@ There are mirrors of the pci.ids file at http://pciids.sourceforge.net/
and https://github.com/pciutils/pciids.

-
-9. Obsolete functions
-~~~~~~~~~~~~~~~~~~~~~
+Obsolete functions
+==================

There are several functions which you might come across when trying to
port an old driver to the new PCI interface. They are no longer present
in the kernel as they aren't compatible with hotplug or PCI domains or
having sane locking.

+================= ===========================================
pci_find_device() Superseded by pci_get_device()
pci_find_subsys() Superseded by pci_get_subsys()
pci_find_slot() Superseded by pci_get_domain_bus_and_slot()
pci_get_slot() Superseded by pci_get_domain_bus_and_slot()
-
+================= ===========================================

The alternative is the traditional PCI device driver that walks PCI
device lists. This is still possible but discouraged.

-
-10. MMIO Space and "Write Posting"
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+MMIO Space and "Write Posting"
+==============================

Converting a driver from using I/O Port space to using MMIO space
often requires some additional changes. Specifically, "write posting"
@@ -609,14 +552,14 @@ the CPU before the transaction has reached its destination.

Thus, timing sensitive code should add readl() where the CPU is
expected to wait before doing other work. The classic "bit banging"
-sequence works fine for I/O Port space:
+sequence works fine for I/O Port space::

for (i = 8; --i; val >>= 1) {
outb(val & 1, ioport_reg); /* write bit */
udelay(10);
}

-The same sequence for MMIO space should be:
+The same sequence for MMIO space should be::

for (i = 8; --i; val >>= 1) {
writeb(val & 1, mmio_reg); /* write bit */
@@ -633,4 +576,3 @@ handle the PCI master abort on all platforms if the PCI device is
expected to not respond to a readl(). Most x86 platforms will allow
MMIO reads to master abort (a.k.a. "Soft Fail") and return garbage
(e.g. ~0). But many RISC platforms will crash (a.k.a."Hard Fail").
-
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 448621c32e4d..c058e5366f06 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -16,6 +16,25 @@ typedef unsigned long kernel_ulong_t;

#define PCI_ANY_ID (~0)

+/**
+ * struct pci_device_id - PCI device ID structure
+ * @vendor： Vendor ID to match (or PCI_ANY_ID)
+ * @device: Device ID to match (or PCI_ANY_ID)
+ * @subvendor: Subsystem vendor ID to match (or PCI_ANY_ID)
+ * @subdevice: Subsystem device ID to match (or PCI_ANY_ID)
+ * @class: Device class, subclass, and "interface" to match.
+ * See Appendix D of the PCI Local Bus Spec or
+ * include/linux/pci_ids.h for a full list of classes.
+ * Most drivers do not need to specify class/class_mask
+ * as vendor/device is normally sufficient.
+ * @class_mask: limit which sub-fields of the class field are compared.
+ * See drivers/scsi/sym53c8xx_2/ for example of usage.
+ * @driver_data: Data private to the driver.
+ * Most drivers don't need to use driver_data field.
+ * Best practice is to use driver_data as an index
+ * into a static list of equivalent device types,
+ * instead of using it as a pointer.
+ */
struct pci_device_id {
__u32 vendor, device; /* Vendor and device ID or PCI_ANY_ID*/
__u32 subvendor, subdevice; /* Subsystem ID's or PCI_ANY_ID */
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 27854731afc4..2b3c3572d1c7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -767,6 +767,43 @@ struct pci_error_handlers {

struct module;
+
+/**
+ * struct pci_driver - PCI driver structure
+ * @id_table: Pointer to table of device ID's the driver is
+ * interested in. Most drivers should export this
+ * table using MODULE_DEVICE_TABLE(pci,...).
+ * @probe: This probing function gets called (during execution
+ * of pci_register_driver() for already existing
+ * devices or later if a new device gets inserted) for
+ * all PCI devices which match the ID table and are not
+ * "owned" by the other drivers yet. This function gets
+ * passed a "struct pci_dev *" for each device whose
+ * entry in the ID table matches the device. The probe
+ * function returns zero when the driver chooses to
+ * take "ownership" of the device or an error code
+ * (negative number) otherwise.
+ * The probe function always gets called from process
+ * context, so it can sleep.
+ * @remove: The remove() function gets called whenever a device
+ * being handled by this driver is removed (either during
+ * deregistration of the driver or when it's manually
+ * pulled out of a hot-pluggable slot).
+ * The remove function always gets called from process
+ * context, so it can sleep.
+ * @suspend: Put device into low power state.
+ * @suspend_late: Put device into low power state.
+ * @resume_early: Wake device from low power state.
+ * @resume: Wake device from low power state.
+ * (Please see Documentation/power/pci.txt for descriptions
+ * of PCI Power Management and the related functions.)
+ * @shutdown: Hook into reboot_notifier_list (kernel/sys.c).
+ * Intended to stop any idling DMA operations.
+ * Useful for enabling wake-on-lan (NIC) or changing
+ * the power state of a device before reboot.
+ * e.g. drivers/net/e100.c.
+ * @err_handler: See Documentation/PCI/pci-error-recovery.rst
+ */
struct pci_driver {
struct list_head node;
const char *name;
--
2.20.1

2019-05-12 12:53:41

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 01/12] Documentation: add Linux PCI to Sphinx TOC tree

Add a index.rst for PCI subsystem. More docs will be added later.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
---
Documentation/PCI/index.rst | 9 +++++++++
Documentation/index.rst | 1 +
2 files changed, 10 insertions(+)
create mode 100644 Documentation/PCI/index.rst

diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
new file mode 100644
index 000000000000..c2f8728d11cf
--- /dev/null
+++ b/Documentation/PCI/index.rst
@@ -0,0 +1,9 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+Linux PCI Bus Subsystem
+=======================
+
+.. toctree::
+ :maxdepth: 2
+ :numbered:
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 9e01aace4f48..fb6477a692b8 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -101,6 +101,7 @@ needed).
filesystems/index
vm/index
bpf/index
+ PCI/index
misc-devices/index

Architecture-specific documentation
--
2.20.1

2019-05-12 12:53:39

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 05/12] Documentation: PCI: convert MSI-HOWTO.txt to reST

2019-05-12 12:53:39

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 07/12] Documentation: PCI: convert pci-error-recovery.txt to reST

This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
---
Documentation/PCI/index.rst | 1 +
...or-recovery.txt => pci-error-recovery.rst} | 287 +++++++++---------
MAINTAINERS | 2 +-
3 files changed, 151 insertions(+), 139 deletions(-)
rename Documentation/PCI/{pci-error-recovery.txt => pci-error-recovery.rst} (67%)

diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
index 6f573f3df993..92e62d0fc9e6 100644
--- a/Documentation/PCI/index.rst
+++ b/Documentation/PCI/index.rst
@@ -13,3 +13,4 @@ Linux PCI Bus Subsystem
pci-iov-howto
msi-howto
acpi-info
+ pci-error-recovery
diff --git a/Documentation/PCI/pci-error-recovery.txt b/Documentation/PCI/pci-error-recovery.rst
similarity index 67%
rename from Documentation/PCI/pci-error-recovery.txt
rename to Documentation/PCI/pci-error-recovery.rst
index 0b6bb3ef449e..83db42092935 100644
--- a/Documentation/PCI/pci-error-recovery.txt
+++ b/Documentation/PCI/pci-error-recovery.rst
@@ -1,12 +1,13 @@
+.. SPDX-License-Identifier: GPL-2.0

- PCI Error Recovery
- ------------------
- February 2, 2006
+==================
+PCI Error Recovery
+==================

- Current document maintainer:
- Linas Vepstas <[email protected]>
- updated by Richard Lary <[email protected]>
- and Mike Mason <[email protected]> on 27-Jul-2009
+
+:Authors: - Linas Vepstas <[email protected]>
+ - Richard Lary <[email protected]>
+ - Mike Mason <[email protected]>

Many PCI bus controllers are able to detect a variety of hardware
@@ -63,7 +64,8 @@ mechanisms for dealing with SCSI bus errors and SCSI bus resets.

Detailed Design
----------------
+===============
+
Design and implementation details below, based on a chain of
public email discussions with Ben Herrenschmidt, circa 5 April 2005.

@@ -73,30 +75,33 @@ pci_driver. A driver that fails to provide the structure is "non-aware",
and the actual recovery steps taken are platform dependent. The
arch/powerpc implementation will simulate a PCI hotplug remove/add.

-This structure has the form:
-struct pci_error_handlers
-{
- int (*error_detected)(struct pci_dev *dev, enum pci_channel_state);
- int (*mmio_enabled)(struct pci_dev *dev);
- int (*slot_reset)(struct pci_dev *dev);
- void (*resume)(struct pci_dev *dev);
-};
-
-The possible channel states are:
-enum pci_channel_state {
- pci_channel_io_normal, /* I/O channel is in normal state */
- pci_channel_io_frozen, /* I/O to channel is blocked */
- pci_channel_io_perm_failure, /* PCI card is dead */
-};
-
-Possible return values are:
-enum pci_ers_result {
- PCI_ERS_RESULT_NONE, /* no result/none/not supported in device driver */
- PCI_ERS_RESULT_CAN_RECOVER, /* Device driver can recover without slot reset */
- PCI_ERS_RESULT_NEED_RESET, /* Device driver wants slot to be reset. */
- PCI_ERS_RESULT_DISCONNECT, /* Device has completely failed, is unrecoverable */
- PCI_ERS_RESULT_RECOVERED, /* Device driver is fully recovered and operational */
-};
+This structure has the form::
+
+ struct pci_error_handlers
+ {
+ int (*error_detected)(struct pci_dev *dev, enum pci_channel_state);
+ int (*mmio_enabled)(struct pci_dev *dev);
+ int (*slot_reset)(struct pci_dev *dev);
+ void (*resume)(struct pci_dev *dev);
+ };
+
+The possible channel states are::
+
+ enum pci_channel_state {
+ pci_channel_io_normal, /* I/O channel is in normal state */
+ pci_channel_io_frozen, /* I/O to channel is blocked */
+ pci_channel_io_perm_failure, /* PCI card is dead */
+ };
+
+Possible return values are::
+
+ enum pci_ers_result {
+ PCI_ERS_RESULT_NONE, /* no result/none/not supported in device driver */
+ PCI_ERS_RESULT_CAN_RECOVER, /* Device driver can recover without slot reset */
+ PCI_ERS_RESULT_NEED_RESET, /* Device driver wants slot to be reset. */
+ PCI_ERS_RESULT_DISCONNECT, /* Device has completely failed, is unrecoverable */
+ PCI_ERS_RESULT_RECOVERED, /* Device driver is fully recovered and operational */
+ };

A driver does not have to implement all of these callbacks; however,
if it implements any, it must implement error_detected(). If a callback
@@ -134,16 +139,17 @@ shouldn't do any new IOs. Called in task context. This is sort of a

All drivers participating in this system must implement this call.
The driver must return one of the following result codes:
- - PCI_ERS_RESULT_CAN_RECOVER:
- Driver returns this if it thinks it might be able to recover
- the HW by just banging IOs or if it wants to be given
- a chance to extract some diagnostic information (see
- mmio_enable, below).
- - PCI_ERS_RESULT_NEED_RESET:
- Driver returns this if it can't recover without a
- slot reset.
- - PCI_ERS_RESULT_DISCONNECT:
- Driver returns this if it doesn't want to recover at all.
+
+ - PCI_ERS_RESULT_CAN_RECOVER
+ Driver returns this if it thinks it might be able to recover
+ the HW by just banging IOs or if it wants to be given
+ a chance to extract some diagnostic information (see
+ mmio_enable, below).
+ - PCI_ERS_RESULT_NEED_RESET
+ Driver returns this if it can't recover without a
+ slot reset.
+ - PCI_ERS_RESULT_DISCONNECT
+ Driver returns this if it doesn't want to recover at all.

The next step taken will depend on the result codes returned by the
drivers.
@@ -159,25 +165,27 @@ then recovery proceeds to STEP 4 (Slot Reset).
If the platform is unable to recover the slot, the next step
is STEP 6 (Permanent Failure).

->>> The current powerpc implementation assumes that a device driver will
->>> *not* schedule or semaphore in this routine; the current powerpc
->>> implementation uses one kernel thread to notify all devices;
->>> thus, if one device sleeps/schedules, all devices are affected.
->>> Doing better requires complex multi-threaded logic in the error
->>> recovery implementation (e.g. waiting for all notification threads
->>> to "join" before proceeding with recovery.) This seems excessively
->>> complex and not worth implementing.
-
->>> 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
->>> a value of 0xff on read, and writes will be dropped. If more than
->>> EEH_MAX_FAILS I/O's are attempted to a frozen adapter, EEH
->>> assumes that the device driver has gone into an infinite loop
->>> and prints an error to syslog. A reboot is then required to
->>> get the device working again.
+.. note::
+
+ The current powerpc implementation assumes that a device driver will
+ *not* schedule or semaphore in this routine; the current powerpc
+ implementation uses one kernel thread to notify all devices;
+ thus, if one device sleeps/schedules, all devices are affected.
+ Doing better requires complex multi-threaded logic in the error
+ recovery implementation (e.g. waiting for all notification threads
+ to "join" before proceeding with recovery.) This seems excessively
+ complex and not worth implementing.
+
+ 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
+ a value of 0xff on read, and writes will be dropped. If more than
+ EEH_MAX_FAILS I/O's are attempted to a frozen adapter, EEH
+ assumes that the device driver has gone into an infinite loop
+ and prints an error to syslog. A reboot is then required to
+ get the device working again.

STEP 2: MMIO Enabled
--------------------
+--------------------
The platform re-enables MMIO to the device (but typically not the
DMA), and then calls the mmio_enabled() callback on all affected
device drivers.
@@ -192,34 +200,36 @@ link reset was performed by the HW. If the platform can't just re-enable IOs
without a slot reset or a link reset, it will not call this callback, and
instead will have gone directly to STEP 3 (Link Reset) or STEP 4 (Slot Reset)

->>> The following is proposed; no platform implements this yet:
->>> Proposal: All I/O's should be done _synchronously_ from within
->>> this callback, errors triggered by them will be returned via
->>> the normal pci_check_whatever() API, no new error_detected()
->>> callback will be issued due to an error happening here. However,
->>> such an error might cause IOs to be re-blocked for the whole
->>> segment, and thus invalidate the recovery that other devices
->>> on the same segment might have done, forcing the whole segment
->>> into one of the next states, that is, link reset or slot reset.
+.. note::
+
+ The following is proposed; no platform implements this yet:
+ Proposal: All I/O's should be done _synchronously_ from within
+ this callback, errors triggered by them will be returned via
+ the normal pci_check_whatever() API, no new error_detected()
+ callback will be issued due to an error happening here. However,
+ such an error might cause IOs to be re-blocked for the whole
+ segment, and thus invalidate the recovery that other devices
+ on the same segment might have done, forcing the whole segment
+ into one of the next states, that is, link reset or slot reset.

The driver should return one of the following result codes:
- - PCI_ERS_RESULT_RECOVERED
- Driver returns this if it thinks the device is fully
- functional and thinks it is ready to start
- normal driver operations again. There is no
- guarantee that the driver will actually be
- allowed to proceed, as another driver on the
- same segment might have failed and thus triggered a
- slot reset on platforms that support it.
-
- - PCI_ERS_RESULT_NEED_RESET
- Driver returns this if it thinks the device is not
- recoverable in its current state and it needs a slot
- reset to proceed.
-
- - PCI_ERS_RESULT_DISCONNECT
- Same as above. Total failure, no recovery even after
- reset driver dead. (To be defined more precisely)
+ - PCI_ERS_RESULT_RECOVERED
+ Driver returns this if it thinks the device is fully
+ functional and thinks it is ready to start
+ normal driver operations again. There is no
+ guarantee that the driver will actually be
+ allowed to proceed, as another driver on the
+ same segment might have failed and thus triggered a
+ slot reset on platforms that support it.
+
+ - PCI_ERS_RESULT_NEED_RESET
+ Driver returns this if it thinks the device is not
+ recoverable in its current state and it needs a slot
+ reset to proceed.
+
+ - PCI_ERS_RESULT_DISCONNECT
+ Same as above. Total failure, no recovery even after
+ reset driver dead. (To be defined more precisely)

The next step taken depends on the results returned by the drivers.
If all drivers returned PCI_ERS_RESULT_RECOVERED, then the platform
@@ -293,31 +303,33 @@ device will be considered "dead" in this case.
Drivers for multi-function cards will need to coordinate among
themselves as to which driver instance will perform any "one-shot"
or global device initialization. For example, the Symbios sym53cxx2
-driver performs device init only from PCI function 0:
+driver performs device init only from PCI function 0::

-+ if (PCI_FUNC(pdev->devfn) == 0)
-+ sym_reset_scsi_bus(np, 0);
+ + if (PCI_FUNC(pdev->devfn) == 0)
+ + sym_reset_scsi_bus(np, 0);

- Result codes:
- - PCI_ERS_RESULT_DISCONNECT
- Same as above.
+Result codes:
+ - PCI_ERS_RESULT_DISCONNECT
+ 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:
+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;
-+
+ + /* 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
Failure).

->>> The current powerpc implementation does not try a power-cycle
->>> reset if the driver returned PCI_ERS_RESULT_DISCONNECT.
->>> However, it probably should.
+.. note::
+
+ The current powerpc implementation does not try a power-cycle
+ reset if the driver returned PCI_ERS_RESULT_DISCONNECT.
+ However, it probably should.

STEP 5: Resume Operations
@@ -370,44 +382,43 @@ The current policy is to turn this into a platform policy.
That is, the recovery API only requires that:

- There is no guarantee that interrupt delivery can proceed from any
-device on the segment starting from the error detection and until the
-slot_reset callback is called, at which point interrupts are expected
-to be fully operational.
+ device on the segment starting from the error detection and until the
+ slot_reset callback is called, at which point interrupts are expected
+ to be fully operational.

- There is no guarantee that interrupt delivery is stopped, that is,
-a driver that gets an interrupt after detecting an error, or that detects
-an error within the interrupt handler such that it prevents proper
-ack'ing of the interrupt (and thus removal of the source) should just
-return IRQ_NOTHANDLED. It's up to the platform to deal with that
-condition, typically by masking the IRQ source during the duration of
-the error handling. It is expected that the platform "knows" which
-interrupts are routed to error-management capable slots and can deal
-with temporarily disabling that IRQ number during error processing (this
-isn't terribly complex). That means some IRQ latency for other devices
-sharing the interrupt, but there is simply no other way. High end
-platforms aren't supposed to share interrupts between many devices
-anyway :)
-
->>> Implementation details for the powerpc platform are discussed in
->>> the file Documentation/powerpc/eeh-pci-error-recovery.txt
-
->>> As of this writing, there is a growing list of device drivers with
->>> patches implementing error recovery. Not all of these patches are in
->>> mainline yet. These may be used as "examples":
->>>
->>> drivers/scsi/ipr
->>> drivers/scsi/sym53c8xx_2
->>> drivers/scsi/qla2xxx
->>> drivers/scsi/lpfc
->>> drivers/next/bnx2.c
->>> drivers/next/e100.c
->>> drivers/net/e1000
->>> drivers/net/e1000e
->>> drivers/net/ixgb
->>> drivers/net/ixgbe
->>> drivers/net/cxgb3
->>> drivers/net/s2io.c
->>> drivers/net/qlge
-
-The End
--------
+ a driver that gets an interrupt after detecting an error, or that detects
+ an error within the interrupt handler such that it prevents proper
+ ack'ing of the interrupt (and thus removal of the source) should just
+ return IRQ_NOTHANDLED. It's up to the platform to deal with that
+ condition, typically by masking the IRQ source during the duration of
+ the error handling. It is expected that the platform "knows" which
+ interrupts are routed to error-management capable slots and can deal
+ with temporarily disabling that IRQ number during error processing (this
+ isn't terribly complex). That means some IRQ latency for other devices
+ sharing the interrupt, but there is simply no other way. High end
+ platforms aren't supposed to share interrupts between many devices
+ anyway :)
+
+.. note::
+
+ Implementation details for the powerpc platform are discussed in
+ the file Documentation/powerpc/eeh-pci-error-recovery.txt
+
+ As of this writing, there is a growing list of device drivers with
+ patches implementing error recovery. Not all of these patches are in
+ mainline yet. These may be used as "examples":
+
+ - drivers/scsi/ipr
+ - drivers/scsi/sym53c8xx_2
+ - drivers/scsi/qla2xxx
+ - drivers/scsi/lpfc
+ - drivers/next/bnx2.c
+ - drivers/next/e100.c
+ - drivers/net/e1000
+ - drivers/net/e1000e
+ - drivers/net/ixgb
+ - drivers/net/ixgbe
+ - drivers/net/cxgb3
+ - drivers/net/s2io.c
+ - drivers/net/qlge
diff --git a/MAINTAINERS b/MAINTAINERS
index 3c65228e93c5..9b965d5b8efa 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12100,7 +12100,7 @@ M: Sam Bobroff <[email protected]>
M: Oliver O'Halloran <[email protected]>
L: [email protected]
S: Supported
-F: Documentation/PCI/pci-error-recovery.txt
+F: Documentation/PCI/pci-error-recovery.rst
F: drivers/pci/pcie/aer.c
F: drivers/pci/pcie/dpc.c
F: drivers/pci/pcie/err.c
--
2.20.1

2019-05-12 12:53:39

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 12/12] Documentation: PCI: convert endpoint/pci-test-howto.txt to reST

2019-05-12 12:54:21

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 11/12] Documentation: PCI: convert endpoint/pci-test-function.txt to reST

This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
---
Documentation/PCI/endpoint/index.rst | 1 +
...est-function.txt => pci-test-function.rst} | 34 ++++++++++++-------
2 files changed, 22 insertions(+), 13 deletions(-)
rename Documentation/PCI/endpoint/{pci-test-function.txt => pci-test-function.rst} (84%)

diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst
index 3951de9f923c..b680a3fc4fec 100644
--- a/Documentation/PCI/endpoint/index.rst
+++ b/Documentation/PCI/endpoint/index.rst
@@ -9,3 +9,4 @@ PCI Endpoint Framework

pci-endpoint
pci-endpoint-cfs
+ pci-test-function
diff --git a/Documentation/PCI/endpoint/pci-test-function.txt b/Documentation/PCI/endpoint/pci-test-function.rst
similarity index 84%
rename from Documentation/PCI/endpoint/pci-test-function.txt
rename to Documentation/PCI/endpoint/pci-test-function.rst
index 5916f1f592bb..63148df97232 100644
--- a/Documentation/PCI/endpoint/pci-test-function.txt
+++ b/Documentation/PCI/endpoint/pci-test-function.rst
@@ -1,5 +1,10 @@
- PCI TEST
- Kishon Vijay Abraham I <[email protected]>
+.. SPDX-License-Identifier: GPL-2.0
+
+=================
+PCI Test Function
+=================
+
+:Author: Kishon Vijay Abraham I <[email protected]>

Traditionally PCI RC has always been validated by using standard
PCI cards like ethernet PCI cards or USB PCI cards or SATA PCI cards.
@@ -23,30 +28,31 @@ The PCI endpoint test device has the following registers:
8) PCI_ENDPOINT_TEST_IRQ_TYPE
9) PCI_ENDPOINT_TEST_IRQ_NUMBER

-*) PCI_ENDPOINT_TEST_MAGIC
+* PCI_ENDPOINT_TEST_MAGIC

This register will be used to test BAR0. A known pattern will be written
and read back from MAGIC register to verify BAR0.

-*) PCI_ENDPOINT_TEST_COMMAND:
+* PCI_ENDPOINT_TEST_COMMAND

This register will be used by the host driver to indicate the function
that the endpoint device must perform.

-Bitfield Description:
+Bitfield Description::
+
Bit 0 : raise legacy IRQ
Bit 1 : raise MSI IRQ
Bit 2 : raise MSI-X IRQ
Bit 3 : read command (read data from RC buffer)
Bit 4 : write command (write data to RC buffer)
- Bit 5 : copy command (copy data from one RC buffer to another
- RC buffer)
+ Bit 5 : copy command (copy data from one RC buffer to another RC buffer)

-*) PCI_ENDPOINT_TEST_STATUS
+* PCI_ENDPOINT_TEST_STATUS

This register reflects the status of the PCI endpoint device.

-Bitfield Description:
+Bitfield Description::
+
Bit 0 : read success
Bit 1 : read fail
Bit 2 : write success
@@ -57,31 +63,33 @@ Bitfield Description:
Bit 7 : source address is invalid
Bit 8 : destination address is invalid

-*) PCI_ENDPOINT_TEST_SRC_ADDR
+* PCI_ENDPOINT_TEST_SRC_ADDR

This register contains the source address (RC buffer address) for the
COPY/READ command.

-*) PCI_ENDPOINT_TEST_DST_ADDR
+* PCI_ENDPOINT_TEST_DST_ADDR

This register contains the destination address (RC buffer address) for
the COPY/WRITE command.

-*) PCI_ENDPOINT_TEST_IRQ_TYPE
+* PCI_ENDPOINT_TEST_IRQ_TYPE

This register contains the interrupt type (Legacy/MSI) triggered
for the READ/WRITE/COPY and raise IRQ (Legacy/MSI) commands.

Possible types:
+
- Legacy : 0
- MSI : 1
- MSI-X : 2

-*) PCI_ENDPOINT_TEST_IRQ_NUMBER
+* PCI_ENDPOINT_TEST_IRQ_NUMBER

This register contains the triggered ID interrupt.

Admissible values:
+
- Legacy : 0
- MSI : [1 .. 32]
- MSI-X : [1 .. 2048]
--
2.20.1

2019-05-12 12:54:54

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 09/12] Documentation: PCI: convert endpoint/pci-endpoint.txt to reST

This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
---
Documentation/PCI/endpoint/index.rst | 10 ++
.../{pci-endpoint.txt => pci-endpoint.rst} | 96 +++++++++++--------
Documentation/PCI/index.rst | 1 +
3 files changed, 69 insertions(+), 38 deletions(-)
create mode 100644 Documentation/PCI/endpoint/index.rst
rename Documentation/PCI/endpoint/{pci-endpoint.txt => pci-endpoint.rst} (82%)

diff --git a/Documentation/PCI/endpoint/index.rst b/Documentation/PCI/endpoint/index.rst
new file mode 100644
index 000000000000..0db4f2fcd7f0
--- /dev/null
+++ b/Documentation/PCI/endpoint/index.rst
@@ -0,0 +1,10 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+PCI Endpoint Framework
+======================
+
+.. toctree::
+ :maxdepth: 2
+
+ pci-endpoint
diff --git a/Documentation/PCI/endpoint/pci-endpoint.txt b/Documentation/PCI/endpoint/pci-endpoint.rst
similarity index 82%
rename from Documentation/PCI/endpoint/pci-endpoint.txt
rename to Documentation/PCI/endpoint/pci-endpoint.rst
index e86a96b66a6a..693f3a2ad7a4 100644
--- a/Documentation/PCI/endpoint/pci-endpoint.txt
+++ b/Documentation/PCI/endpoint/pci-endpoint.rst
@@ -1,11 +1,17 @@
- PCI ENDPOINT FRAMEWORK
- Kishon Vijay Abraham I <[email protected]>
+.. SPDX-License-Identifier: GPL-2.0
+
+======================
+PCI Endpoint Framework
+======================
+
+:Author: Kishon Vijay Abraham I <[email protected]>

This document is a guide to use the PCI Endpoint Framework in order to create
endpoint controller driver, endpoint function driver, and using configfs
interface to bind the function driver to the controller driver.

-1. Introduction
+Introduction
+============

Linux has a comprehensive PCI subsystem to support PCI controllers that
operates in Root Complex mode. The subsystem has capability to scan PCI bus,
@@ -19,26 +25,30 @@ add endpoint mode support in Linux. This will help to run Linux in an
EP system which can have a wide variety of use cases from testing or
validation, co-processor accelerator, etc.

-2. PCI Endpoint Core
+PCI Endpoint Core
+=================

The PCI Endpoint Core layer comprises 3 components: the Endpoint Controller
library, the Endpoint Function library, and the configfs layer to bind the
endpoint function with the endpoint controller.

-2.1 PCI Endpoint Controller(EPC) Library
+PCI Endpoint Controller(EPC) Library
+------------------------------------

The EPC library provides APIs to be used by the controller that can operate
in endpoint mode. It also provides APIs to be used by function driver/library
in order to implement a particular endpoint function.

-2.1.1 APIs for the PCI controller Driver
+APIs for the PCI controller Driver
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This section lists the APIs that the PCI Endpoint core provides to be used
by the PCI controller driver.

-*) devm_pci_epc_create()/pci_epc_create()
+* devm_pci_epc_create()/pci_epc_create()

The PCI controller driver should implement the following ops:
+
* write_header: ops to populate configuration space header
* set_bar: ops to configure the BAR
* clear_bar: ops to reset the BAR
@@ -51,110 +61,116 @@ by the PCI controller driver.
The PCI controller driver can then create a new EPC device by invoking
devm_pci_epc_create()/pci_epc_create().

-*) devm_pci_epc_destroy()/pci_epc_destroy()
+* devm_pci_epc_destroy()/pci_epc_destroy()

The PCI controller driver can destroy the EPC device created by either
devm_pci_epc_create() or pci_epc_create() using devm_pci_epc_destroy() or
pci_epc_destroy().

-*) pci_epc_linkup()
+* pci_epc_linkup()

In order to notify all the function devices that the EPC device to which
they are linked has established a link with the host, the PCI controller
driver should invoke pci_epc_linkup().

-*) pci_epc_mem_init()
+* pci_epc_mem_init()

Initialize the pci_epc_mem structure used for allocating EPC addr space.

-*) pci_epc_mem_exit()
+* pci_epc_mem_exit()

Cleanup the pci_epc_mem structure allocated during pci_epc_mem_init().

-2.1.2 APIs for the PCI Endpoint Function Driver
+
+APIs for the PCI Endpoint Function Driver
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This section lists the APIs that the PCI Endpoint core provides to be used
by the PCI endpoint function driver.

-*) pci_epc_write_header()
+* pci_epc_write_header()

The PCI endpoint function driver should use pci_epc_write_header() to
write the standard configuration header to the endpoint controller.

-*) pci_epc_set_bar()
+* pci_epc_set_bar()

The PCI endpoint function driver should use pci_epc_set_bar() to configure
the Base Address Register in order for the host to assign PCI addr space.
Register space of the function driver is usually configured
using this API.

-*) pci_epc_clear_bar()
+* pci_epc_clear_bar()

The PCI endpoint function driver should use pci_epc_clear_bar() to reset
the BAR.

-*) pci_epc_raise_irq()
+* pci_epc_raise_irq()

The PCI endpoint function driver should use pci_epc_raise_irq() to raise
Legacy Interrupt, MSI or MSI-X Interrupt.

-*) pci_epc_mem_alloc_addr()
+* pci_epc_mem_alloc_addr()

The PCI endpoint function driver should use pci_epc_mem_alloc_addr(), to
allocate memory address from EPC addr space which is required to access
RC's buffer

-*) pci_epc_mem_free_addr()
+* pci_epc_mem_free_addr()

The PCI endpoint function driver should use pci_epc_mem_free_addr() to
free the memory space allocated using pci_epc_mem_alloc_addr().

-2.1.3 Other APIs
+Other APIs
+~~~~~~~~~~

There are other APIs provided by the EPC library. These are used for binding
the EPF device with EPC device. pci-ep-cfs.c can be used as reference for
using these APIs.

-*) pci_epc_get()
+* pci_epc_get()

Get a reference to the PCI endpoint controller based on the device name of
the controller.

-*) pci_epc_put()
+* pci_epc_put()

Release the reference to the PCI endpoint controller obtained using
pci_epc_get()

-*) pci_epc_add_epf()
+* pci_epc_add_epf()

Add a PCI endpoint function to a PCI endpoint controller. A PCIe device
can have up to 8 functions according to the specification.

-*) pci_epc_remove_epf()
+* pci_epc_remove_epf()

Remove the PCI endpoint function from PCI endpoint controller.

-*) pci_epc_start()
+* pci_epc_start()

The PCI endpoint function driver should invoke pci_epc_start() once it
has configured the endpoint function and wants to start the PCI link.

-*) pci_epc_stop()
+* pci_epc_stop()

The PCI endpoint function driver should invoke pci_epc_stop() to stop
the PCI LINK.

-2.2 PCI Endpoint Function(EPF) Library
+
+PCI Endpoint Function(EPF) Library
+----------------------------------

The EPF library provides APIs to be used by the function driver and the EPC
library to provide endpoint mode functionality.

-2.2.1 APIs for the PCI Endpoint Function Driver
+APIs for the PCI Endpoint Function Driver
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This section lists the APIs that the PCI Endpoint core provides to be used
by the PCI endpoint function driver.

-*) pci_epf_register_driver()
+* pci_epf_register_driver()

The PCI Endpoint Function driver should implement the following ops:
* bind: ops to perform when a EPC device has been bound to EPF device
@@ -166,50 +182,54 @@ by the PCI endpoint function driver.
The PCI Function driver can then register the PCI EPF driver by using
pci_epf_register_driver().

-*) pci_epf_unregister_driver()
+* pci_epf_unregister_driver()

The PCI Function driver can unregister the PCI EPF driver by using
pci_epf_unregister_driver().

-*) pci_epf_alloc_space()
+* pci_epf_alloc_space()

The PCI Function driver can allocate space for a particular BAR using
pci_epf_alloc_space().

-*) pci_epf_free_space()
+* pci_epf_free_space()

The PCI Function driver can free the allocated space
(using pci_epf_alloc_space) by invoking pci_epf_free_space().

-2.2.2 APIs for the PCI Endpoint Controller Library
+APIs for the PCI Endpoint Controller Library
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
This section lists the APIs that the PCI Endpoint core provides to be used
by the PCI endpoint controller library.

-*) pci_epf_linkup()
+* pci_epf_linkup()

The PCI endpoint controller library invokes pci_epf_linkup() when the
EPC device has established the connection to the host.

-2.2.2 Other APIs
+Other APIs
+~~~~~~~~~~
+
There are other APIs provided by the EPF library. These are used to notify
the function driver when the EPF device is bound to the EPC device.
pci-ep-cfs.c can be used as reference for using these APIs.

-*) pci_epf_create()
+* pci_epf_create()

Create a new PCI EPF device by passing the name of the PCI EPF device.
This name will be used to bind the the EPF device to a EPF driver.

-*) pci_epf_destroy()
+* pci_epf_destroy()

Destroy the created PCI EPF device.

-*) pci_epf_bind()
+* pci_epf_bind()

pci_epf_bind() should be invoked when the EPF device has been bound to
a EPC device.

-*) pci_epf_unbind()
+* pci_epf_unbind()

pci_epf_unbind() should be invoked when the binding between EPC device
and EPF device is lost.
diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
index f54b65b1ca5f..f4c6121868c3 100644
--- a/Documentation/PCI/index.rst
+++ b/Documentation/PCI/index.rst
@@ -15,3 +15,4 @@ Linux PCI Bus Subsystem
acpi-info
pci-error-recovery
pcieaer-howto
+ endpoint/index
--
2.20.1

2019-05-12 12:54:54

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 03/12] Documentation: PCI: convert PCIEBUS-HOWTO.txt to reST

2019-05-12 12:54:54

by Changbin Du

[permalink] [raw]

Subject: [PATCH v4 08/12] Documentation: PCI: convert pcieaer-howto.txt to reST

This converts the plain text documentation to reStructuredText format and
add it to Sphinx TOC tree. No essential content change.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
Cc: Mauro Carvalho Chehab <[email protected]>
---
Documentation/PCI/index.rst | 1 +
.../{pcieaer-howto.txt => pcieaer-howto.rst} | 156 +++++++++++-------
2 files changed, 101 insertions(+), 56 deletions(-)
rename Documentation/PCI/{pcieaer-howto.txt => pcieaer-howto.rst} (72%)

diff --git a/Documentation/PCI/index.rst b/Documentation/PCI/index.rst
index 92e62d0fc9e6..f54b65b1ca5f 100644
--- a/Documentation/PCI/index.rst
+++ b/Documentation/PCI/index.rst
@@ -14,3 +14,4 @@ Linux PCI Bus Subsystem
msi-howto
acpi-info
pci-error-recovery
+ pcieaer-howto
diff --git a/Documentation/PCI/pcieaer-howto.txt b/Documentation/PCI/pcieaer-howto.rst
similarity index 72%
rename from Documentation/PCI/pcieaer-howto.txt
rename to Documentation/PCI/pcieaer-howto.rst
index 48ce7903e3c6..18bdefaafd1a 100644
--- a/Documentation/PCI/pcieaer-howto.txt
+++ b/Documentation/PCI/pcieaer-howto.rst
@@ -1,21 +1,29 @@
- The PCI Express Advanced Error Reporting Driver Guide HOWTO
- T. Long Nguyen <[email protected]>
- Yanmin Zhang <[email protected]>
- 07/29/2006
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>

+===========================================================
+The PCI Express Advanced Error Reporting Driver Guide HOWTO
+===========================================================

-1. Overview
+:Authors: - T. Long Nguyen <[email protected]>
+ - Yanmin Zhang <[email protected]>

-1.1 About this guide
+:Copyright: |copy| 2006 Intel Corporation
+
+Overview
+===========
+
+About this guide
+----------------

This guide describes the basics of the PCI Express Advanced Error
Reporting (AER) driver and provides information on how to use it, as
well as how to enable the drivers of endpoint devices to conform with
PCI Express AER driver.

-1.2 Copyright (C) Intel Corporation 2006.

-1.3 What is the PCI Express AER Driver?
+What is the PCI Express AER Driver?
+-----------------------------------

PCI Express error signaling can occur on the PCI Express link itself
or on behalf of transactions initiated on the link. PCI Express
@@ -30,17 +38,19 @@ The PCI Express AER driver provides the infrastructure to support PCI
Express Advanced Error Reporting capability. The PCI Express AER
driver provides three basic functions:

-- Gathers the comprehensive error information if errors occurred.
-- Reports error to the users.
-- Performs error recovery actions.
+ - Gathers the comprehensive error information if errors occurred.
+ - Reports error to the users.
+ - Performs error recovery actions.

AER driver only attaches root ports which support PCI-Express AER
capability.

-2. User Guide
+User Guide
+==========

-2.1 Include the PCI Express AER Root Driver into the Linux Kernel
+Include the PCI Express AER Root Driver into the Linux Kernel
+-------------------------------------------------------------

The PCI Express AER Root driver is a Root Port service driver attached
to the PCI Express Port Bus driver. If a user wants to use it, the driver
@@ -48,7 +58,8 @@ has to be compiled. Option CONFIG_PCIEAER supports this capability. It
depends on CONFIG_PCIEPORTBUS, so pls. set CONFIG_PCIEPORTBUS=y and
CONFIG_PCIEAER = y.

-2.2 Load PCI Express AER Root Driver
+Load PCI Express AER Root Driver
+--------------------------------

Some systems have AER support in firmware. Enabling Linux AER support at
the same time the firmware handles AER may result in unpredictable
@@ -56,30 +67,34 @@ behavior. Therefore, Linux does not handle AER events unless the firmware
grants AER control to the OS via the ACPI _OSC method. See the PCI FW 3.0
Specification for details regarding _OSC usage.

-2.3 AER error output
+AER error output
+----------------

When a PCIe AER error is captured, an error message will be output to
console. If it's a correctable error, it is output as a warning.
Otherwise, it is printed as an error. So users could choose different
log level to filter out correctable error messages.

-Below shows an example:
-0000:50:00.0: PCIe Bus Error: severity=Uncorrected (Fatal), type=Transaction Layer, id=0500(Requester ID)
-0000:50:00.0: device [8086:0329] error status/mask=00100000/00000000
-0000:50:00.0: [20] Unsupported Request (First)
-0000:50:00.0: TLP Header: 04000001 00200a03 05010000 00050100
+Below shows an example::
+
+ 0000:50:00.0: PCIe Bus Error: severity=Uncorrected (Fatal), type=Transaction Layer, id=0500(Requester ID)
+ 0000:50:00.0: device [8086:0329] error status/mask=00100000/00000000
+ 0000:50:00.0: [20] Unsupported Request (First)
+ 0000:50:00.0: TLP Header: 04000001 00200a03 05010000 00050100

In the example, 'Requester ID' means the ID of the device who sends
the error message to root port. Pls. refer to pci express specs for
other fields.

-2.4 AER Statistics / Counters
+AER Statistics / Counters
+-------------------------

When PCIe AER errors are captured, the counters / statistics are also exposed
in the form of sysfs attributes which are documented at
Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats

-3. Developer Guide
+Developer Guide
+===============

To enable AER aware support requires a software driver to configure
the AER capability structure within its device and to provide callbacks.
@@ -120,7 +135,8 @@ hierarchy and links. These errors do not include any device specific
errors because device specific errors will still get sent directly to
the device driver.

-3.1 Configure the AER capability structure
+Configure the AER capability structure
+--------------------------------------

AER aware drivers of PCI Express component need change the device
control registers to enable AER. They also could change AER registers,
@@ -128,9 +144,11 @@ including mask and severity registers. Helper function
pci_enable_pcie_error_reporting could be used to enable AER. See
section 3.3.

-3.2. Provide callbacks
+Provide callbacks
+-----------------

-3.2.1 callback reset_link to reset pci express link
+callback reset_link to reset pci express link
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This callback is used to reset the pci express physical link when a
fatal error happens. The root port aer service driver provides a
@@ -140,13 +158,15 @@ upstream ports should provide their own reset_link functions.

In struct pcie_port_service_driver, a new pointer, reset_link, is
added.
+::

-pci_ers_result_t (*reset_link) (struct pci_dev *dev);
+ pci_ers_result_t (*reset_link) (struct pci_dev *dev);

Section 3.2.2.2 provides more detailed info on when to call
reset_link.

-3.2.2 PCI error-recovery callbacks
+PCI error-recovery callbacks
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The PCI Express AER Root driver uses error callbacks to coordinate
with downstream device drivers associated with a hierarchy in question
@@ -161,7 +181,8 @@ definitions of the callbacks.

Below sections specify when to call the error callback functions.

-3.2.2.1 Correctable errors
+Correctable errors
+~~~~~~~~~~~~~~~~~~

Correctable errors pose no impacts on the functionality of
the interface. The PCI Express protocol can recover without any
@@ -169,13 +190,16 @@ software intervention or any loss of data. These errors do not
require any recovery actions. The AER driver clears the device's
correctable error status register accordingly and logs these errors.

-3.2.2.2 Non-correctable (non-fatal and fatal) errors
+Non-correctable (non-fatal and fatal) errors
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If an error message indicates a non-fatal error, performing link reset
at upstream is not required. The AER driver calls error_detected(dev,
pci_channel_io_normal) to all drivers associated within a hierarchy in
-question. for example,
-EndPoint<==>DownstreamPort B<==>UpstreamPort A<==>RootPort.
+question. for example::
+
+ EndPoint<==>DownstreamPort B<==>UpstreamPort A<==>RootPort
+
If Upstream port A captures an AER error, the hierarchy consists of
Downstream port B and EndPoint.

@@ -199,53 +223,72 @@ function. If error_detected returns PCI_ERS_RESULT_CAN_RECOVER and
reset_link returns PCI_ERS_RESULT_RECOVERED, the error handling goes
to mmio_enabled.

-3.3 helper functions
+helper functions
+----------------
+::
+
+ int pci_enable_pcie_error_reporting(struct pci_dev *dev);

-3.3.1 int pci_enable_pcie_error_reporting(struct pci_dev *dev);
pci_enable_pcie_error_reporting enables the device to send error
messages to root port when an error is detected. Note that devices
don't enable the error reporting by default, so device drivers need
call this function to enable it.

-3.3.2 int pci_disable_pcie_error_reporting(struct pci_dev *dev);
+::
+
+ int pci_disable_pcie_error_reporting(struct pci_dev *dev);
+
pci_disable_pcie_error_reporting disables the device to send error
messages to root port when an error is detected.

-3.3.3 int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
+::
+
+ int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);`
+
pci_cleanup_aer_uncorrect_error_status cleanups the uncorrectable
error status register.

-3.4 Frequent Asked Questions
+Frequent Asked Questions
+------------------------

-Q: What happens if a PCI Express device driver does not provide an
-error recovery handler (pci_driver->err_handler is equal to NULL)?
+Q:
+ What happens if a PCI Express device driver does not provide an
+ error recovery handler (pci_driver->err_handler is equal to NULL)?

-A: The devices attached with the driver won't be recovered. If the
-error is fatal, kernel will print out warning messages. Please refer
-to section 3 for more information.
+A:
+ The devices attached with the driver won't be recovered. If the
+ error is fatal, kernel will print out warning messages. Please refer
+ to section 3 for more information.

-Q: What happens if an upstream port service driver does not provide
-callback reset_link?
+Q:
+ What happens if an upstream port service driver does not provide
+ callback reset_link?

-A: Fatal error recovery will fail if the errors are reported by the
-upstream ports who are attached by the service driver.
+A:
+ Fatal error recovery will fail if the errors are reported by the
+ upstream ports who are attached by the service driver.

-Q: How does this infrastructure deal with driver that is not PCI
-Express aware?
+Q:
+ How does this infrastructure deal with driver that is not PCI
+ Express aware?

-A: This infrastructure calls the error callback functions of the
-driver when an error happens. But if the driver is not aware of
-PCI Express, the device might not report its own errors to root
-port.
+A:
+ This infrastructure calls the error callback functions of the
+ driver when an error happens. But if the driver is not aware of
+ PCI Express, the device might not report its own errors to root
+ port.

-Q: What modifications will that driver need to make it compatible
-with the PCI Express AER Root driver?
+Q:
+ What modifications will that driver need to make it compatible
+ with the PCI Express AER Root driver?

-A: It could call the helper functions to enable AER in devices and
-cleanup uncorrectable status register. Pls. refer to section 3.3.
+A:
+ It could call the helper functions to enable AER in devices and
+ cleanup uncorrectable status register. Pls. refer to section 3.3.

-4. Software error injection
+Software error injection
+========================

Debugging PCIe AER error recovery code is quite difficult because it
is hard to trigger real hardware errors. Software based error
@@ -261,6 +304,7 @@ After reboot with new kernel or insert the module, a device file named

Then, you need a user space tool named aer-inject, which can be gotten
from:
+
https://git.kernel.org/cgit/linux/kernel/git/gong.chen/aer-inject.git/

More information about aer-inject can be found in the document comes
--
2.20.1

2019-05-12 14:23:21

by Joe Perches

[permalink] [raw]

Subject: Re: [PATCH v4 07/12] Documentation: PCI: convert pci-error-recovery.txt to reST

On Sun, 2019-05-12 at 20:50 +0800, Changbin Du wrote:
> This converts the plain text documentation to reStructuredText format and
> add it to Sphinx TOC tree. No essential content change.
[]
> diff --git a/MAINTAINERS b/MAINTAINERS
[]
> @@ -12100,7 +12100,7 @@ M: Sam Bobroff <[email protected]>
> M: Oliver O'Halloran <[email protected]>
> L: [email protected]
> S: Supported
> -F: Documentation/PCI/pci-error-recovery.txt
> +F: Documentation/PCI/pci-error-recovery.rst
> F: drivers/pci/pcie/aer.c
> F: drivers/pci/pcie/dpc.c
> F: drivers/pci/pcie/err.c

There is another section to update as well:

PCI ERROR RECOVERY
M: Linas Vepstas <[email protected]>
L: [email protected]
S: Supported
F: Documentation/PCI/pci-error-recovery.txt

2019-05-13 14:24:07

by Changbin Du

[permalink] [raw]

Subject: Re: [PATCH v4 07/12] Documentation: PCI: convert pci-error-recovery.txt to reST

On Sun, May 12, 2019 at 07:22:13AM -0700, Joe Perches wrote:
> On Sun, 2019-05-12 at 20:50 +0800, Changbin Du wrote:
> > This converts the plain text documentation to reStructuredText format and
> > add it to Sphinx TOC tree. No essential content change.
> []
> > diff --git a/MAINTAINERS b/MAINTAINERS
> []
> > @@ -12100,7 +12100,7 @@ M: Sam Bobroff <[email protected]>
> > M: Oliver O'Halloran <[email protected]>
> > L: [email protected]
> > S: Supported
> > -F: Documentation/PCI/pci-error-recovery.txt
> > +F: Documentation/PCI/pci-error-recovery.rst
> > F: drivers/pci/pcie/aer.c
> > F: drivers/pci/pcie/dpc.c
> > F: drivers/pci/pcie/err.c
>
> There is another section to update as well:
>
> PCI ERROR RECOVERY
> M: Linas Vepstas <[email protected]>
> L: [email protected]
> S: Supported
> F: Documentation/PCI/pci-error-recovery.txt
>
>
Will update it. Thanks!

--
Cheers,
Changbin Du