Re: [PATCH v5 02/12] Documentation: PCI: convert pci.txt to reST

Mauro Carvalho Chehab
2019-05-13T14:53:16Z

Em Mon, 13 May 2019 22:19:50 +0800
Changbin Du <changbin.du@gmail.com> escreveu:

> 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 <changbin.du@gmail.com>
> Acked-by: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

> ---
> 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 <mj@ucw.cz> on 07-Feb-2000
> - updated by Grant Grundler <grundler@parisc-linux.org> on 23-Dec-2006
> +:Authors: - Martin Mares <mj@ucw.cz>
> + - Grant Grundler <grundler@parisc-linux.org>
>
> -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 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" <linux-pci@atrey.karlin.mff.cuni.cz> 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..f433fb231961 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 1250806dc94a..2303f426842c 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;

Thanks,
Mauro