Provided by: freebsd-manpages_12.0-1_all bug

NAME

     pci, pci_alloc_msi, pci_alloc_msix, pci_disable_busmaster, pci_disable_io,
     pci_enable_busmaster, pci_enable_io, pci_find_bsf, pci_find_cap, pci_find_dbsf,
     pci_find_device, pci_find_extcap, pci_find_htcap, pci_find_next_cap, pci_find_next_extcap,
     pci_find_next_htcap, pci_find_pcie_root_port, pci_get_id, pci_get_max_payload,
     pci_get_max_read_req, pci_get_powerstate, pci_get_vpd_ident, pci_get_vpd_readonly,
     pci_iov_attach, pci_iov_attach_name, pci_iov_detach, pci_msi_count, pci_msix_count,
     pci_msix_pba_bar, pci_msix_table_bar, pci_pending_msix, pci_read_config, pci_release_msi,
     pci_remap_msix, pci_restore_state, pci_save_state, pci_set_max_read_req, pci_set_powerstate,
     pci_write_config, pcie_adjust_config, pcie_flr, pcie_get_max_completion_timeout,
     pcie_read_config, pcie_wait_for_pending_transactions, pcie_write_config — PCI bus interface

SYNOPSIS

     #include <sys/bus.h>
     #include <dev/pci/pcireg.h>
     #include <dev/pci/pcivar.h>

     int
     pci_alloc_msi(device_t dev, int *count);

     int
     pci_alloc_msix(device_t dev, int *count);

     int
     pci_disable_busmaster(device_t dev);

     int
     pci_disable_io(device_t dev, int space);

     int
     pci_enable_busmaster(device_t dev);

     int
     pci_enable_io(device_t dev, int space);

     device_t
     pci_find_bsf(uint8_t bus, uint8_t slot, uint8_t func);

     int
     pci_find_cap(device_t dev, int capability, int *capreg);

     device_t
     pci_find_dbsf(uint32_t domain, uint8_t bus, uint8_t slot, uint8_t func);

     device_t
     pci_find_device(uint16_t vendor, uint16_t device);

     int
     pci_find_extcap(device_t dev, int capability, int *capreg);

     int
     pci_find_htcap(device_t dev, int capability, int *capreg);

     int
     pci_find_next_cap(device_t dev, int capability, int start, int *capreg);

     int
     pci_find_next_extcap(device_t dev, int capability, int start, int *capreg);

     int
     pci_find_next_htcap(device_t dev, int capability, int start, int *capreg);

     device_t
     pci_find_pcie_root_port(device_t dev);

     int
     pci_get_id(device_t dev, enum pci_id_type type, uintptr_t *id);

     int
     pci_get_max_payload(device_t dev);

     int
     pci_get_max_read_req(device_t dev);

     int
     pci_get_powerstate(device_t dev);

     int
     pci_get_vpd_ident(device_t dev, const char **identptr);

     int
     pci_get_vpd_readonly(device_t dev, const char *kw, const char **vptr);

     int
     pci_msi_count(device_t dev);

     int
     pci_msix_count(device_t dev);

     int
     pci_msix_pba_bar(device_t dev);

     int
     pci_msix_table_bar(device_t dev);

     int
     pci_pending_msix(device_t dev, u_int index);

     uint32_t
     pci_read_config(device_t dev, int reg, int width);

     int
     pci_release_msi(device_t dev);

     int
     pci_remap_msix(device_t dev, int count, const u_int *vectors);

     void
     pci_restore_state(device_t dev);

     void
     pci_save_state(device_t dev);

     int
     pci_set_max_read_req(device_t dev, int size);

     int
     pci_set_powerstate(device_t dev, int state);

     void
     pci_write_config(device_t dev, int reg, uint32_t val, int width);

     uint32_t
     pcie_adjust_config(device_t dev, int reg, uint32_t mask, uint32_t val, int width);

     bool
     pcie_flr(device_t dev, u_int max_delay, bool force);

     int
     pcie_get_max_completion_timeout(device_t dev);

     uint32_t
     pcie_read_config(device_t dev, int reg, int width);

     bool
     pcie_wait_for_pending_transactions(device_t dev, u_int max_delay);

     void
     pcie_write_config(device_t dev, int reg, uint32_t val, int width);

     void
     pci_event_fn(void *arg, device_t dev);

     EVENTHANDLER_REGISTER(pci_add_device, pci_event_fn);

     EVENTHANDLER_DEREGISTER(pci_delete_resource, pci_event_fn);

     #include <dev/pci/pci_iov.h>

     int
     pci_iov_attach(device_t dev, nvlist_t *pf_schema, nvlist_t *vf_schema);

     int
     pci_iov_attach_name(device_t dev, nvlist_t *pf_schema, nvlist_t *vf_schema, const char *fmt,
         ...);

     int
     pci_iov_detach(device_t dev);

DESCRIPTION

     The pci set of functions are used for managing PCI devices.  The functions are split into
     several groups: raw configuration access, locating devices, device information, device
     configuration, and message signaled interrupts.

   Raw Configuration Access
     The pci_read_config() function is used to read data from the PCI configuration space of the
     device dev, at offset reg, with width specifying the size of the access.

     The pci_write_config() function is used to write the value val to the PCI configuration
     space of the device dev, at offset reg, with width specifying the size of the access.

     The pcie_adjust_config() function is used to modify the value of a register in the PCI-
     express capability register set of device dev.  The offset reg specifies a relative offset
     in the register set with width specifying the size of the access.  The new value of the
     register is computed by modifying bits set in mask to the value in val.  Any bits not
     specified in mask are preserved.  The previous value of the register is returned.

     The pcie_read_config() function is used to read the value of a register in the PCI-express
     capability register set of device dev.  The offset reg specifies a relative offset in the
     register set with width specifying the size of the access.

     The pcie_write_config() function is used to write the value val to a register in the PCI-
     express capability register set of device dev.  The offset reg specifies a relative offset
     in the register set with width specifying the size of the access.

     NOTE: Device drivers should only use these functions for functionality that is not available
     via another pci() function.

   Locating Devices
     The pci_find_bsf() function looks up the device_t of a PCI device, given its bus, slot, and
     func.  The slot number actually refers to the number of the device on the bus, which does
     not necessarily indicate its geographic location in terms of a physical slot.  Note that in
     case the system has multiple PCI domains, the pci_find_bsf() function only searches the
     first one.  Actually, it is equivalent to:

           pci_find_dbsf(0, bus, slot, func);

     The pci_find_dbsf() function looks up the device_t of a PCI device, given its domain, bus,
     slot, and func.  The slot number actually refers to the number of the device on the bus,
     which does not necessarily indicate its geographic location in terms of a physical slot.

     The pci_find_device() function looks up the device_t of a PCI device, given its vendor and
     device IDs.  Note that there can be multiple matches for this search; this function only
     returns the first matching device.

   Device Information
     The pci_find_cap() function is used to locate the first instance of a PCI capability
     register set for the device dev.  The capability to locate is specified by ID via
     capability.  Constant macros of the form PCIY_xxx for standard capability IDs are defined in
     <dev/pci/pcireg.h>.  If the capability is found, then *capreg is set to the offset in
     configuration space of the capability register set, and pci_find_cap() returns zero.  If the
     capability is not found or the device does not support capabilities, pci_find_cap() returns
     an error.  The pci_find_next_cap() function is used to locate the next instance of a PCI
     capability register set for the device dev.  The start should be the *capreg returned by a
     prior pci_find_cap() or pci_find_next_cap().  When no more instances are located
     pci_find_next_cap() returns an error.

     The pci_find_extcap() function is used to locate the first instance of a PCI-express
     extended capability register set for the device dev.  The extended capability to locate is
     specified by ID via capability.  Constant macros of the form PCIZ_xxx for standard extended
     capability IDs are defined in <dev/pci/pcireg.h>.  If the extended capability is found, then
     *capreg is set to the offset in configuration space of the extended capability register set,
     and pci_find_extcap() returns zero.  If the extended capability is not found or the device
     is not a PCI-express device, pci_find_extcap() returns an error.  The pci_find_next_extcap()
     function is used to locate the next instance of a PCI-express extended capability register
     set for the device dev.  The start should be the *capreg returned by a prior
     pci_find_extcap() or pci_find_next_extcap().  When no more instances are located
     pci_find_next_extcap() returns an error.

     The pci_find_htcap() function is used to locate the first instance of a HyperTransport
     capability register set for the device dev.  The capability to locate is specified by type
     via capability.  Constant macros of the form PCIM_HTCAP_xxx for standard HyperTransport
     capability types are defined in <dev/pci/pcireg.h>.  If the capability is found, then
     *capreg is set to the offset in configuration space of the capability register set, and
     pci_find_htcap() returns zero.  If the capability is not found or the device is not a
     HyperTransport device, pci_find_htcap() returns an error.  The pci_find_next_htcap()
     function is used to locate the next instance of a HyperTransport capability register set for
     the device dev.  The start should be the *capreg returned by a prior pci_find_htcap() or
     pci_find_next_htcap().  When no more instances are located pci_find_next_htcap() returns an
     error.

     The pci_find_pcie_root_port() function walks up the PCI device hierarchy to locate the PCI-
     express root port upstream of dev.  If a root port is not found, pci_find_pcie_root_port()
     returns NULL.

     The pci_get_id() function is used to read an identifier from a device.  The type flag is
     used to specify which identifier to read.  The following flags are supported:

     PCI_ID_RID  Read the routing identifier for the device.

     PCI_ID_MSI  Read the MSI routing ID.  This is needed by some interrupt controllers to route
                 MSI and MSI-X interrupts.

     The pci_get_vpd_ident() function is used to fetch a device's Vital Product Data (VPD)
     identifier string.  If the device dev supports VPD and provides an identifier string, then
     *identptr is set to point at a read-only, null-terminated copy of the identifier string, and
     pci_get_vpd_ident() returns zero.  If the device does not support VPD or does not provide an
     identifier string, then pci_get_vpd_ident() returns an error.

     The pci_get_vpd_readonly() function is used to fetch the value of a single VPD read-only
     keyword for the device dev.  The keyword to fetch is identified by the two character string
     kw.  If the device supports VPD and provides a read-only value for the requested keyword,
     then *vptr is set to point at a read-only, null-terminated copy of the value, and
     pci_get_vpd_readonly() returns zero.  If the device does not support VPD or does not provide
     the requested keyword, then pci_get_vpd_readonly() returns an error.

     The pcie_get_max_completion_timeout() function returns the maximum completion timeout
     configured for the device dev in microseconds.  If the dev device is not a PCI-express
     device, pcie_get_max_completion_timeout() returns zero.  When completion timeouts are
     disabled for dev, this function returns the maxmimum timeout that would be used if timeouts
     were enabled.

     The pcie_wait_for_pending_transactions() function waits for any pending transactions
     initiated by the dev device to complete.  The function checks for pending transactions by
     polling the transactions pending flag in the PCI-express device status register.  It returns
     true once the transaction pending flag is clear.  If transactions are still pending after
     max_delay milliseconds, pcie_wait_for_pending_transactions() returns false.  If max_delay is
     set to zero, pcie_wait_for_pending_transactions() performs a single check; otherwise, this
     function may sleep while polling the transactions pending flag.
     pcie_wait_for_pending_transactions returns true if dev is not a PCI-express device.

   Device Configuration
     The pci_enable_busmaster() function enables PCI bus mastering for the device dev, by setting
     the PCIM_CMD_BUSMASTEREN bit in the PCIR_COMMAND register.  The pci_disable_busmaster()
     function clears this bit.

     The pci_enable_io() function enables memory or I/O port address decoding for the device dev,
     by setting the PCIM_CMD_MEMEN or PCIM_CMD_PORTEN bit in the PCIR_COMMAND register
     appropriately.  The pci_disable_io() function clears the appropriate bit.  The space
     argument specifies which resource is affected; this can be either SYS_RES_MEMORY or
     SYS_RES_IOPORT as appropriate.  Device drivers should generally not use these routines
     directly.  The PCI bus will enable decoding automatically when a SYS_RES_MEMORY or
     SYS_RES_IOPORT resource is activated via bus_alloc_resource(9) or bus_activate_resource(9).

     The pci_get_max_payload() function returns the current maximum TLP payload size in bytes for
     a PCI-express device.  If the dev device is not a PCI-express device, pci_get_max_payload()
     returns zero.

     The pci_get_max_read_req() function returns the current maximum read request size in bytes
     for a PCI-express device.  If the dev device is not a PCI-express device,
     pci_get_max_read_req() returns zero.

     The pci_set_max_read_req() sets the PCI-express maximum read request size for dev.  The
     requested size may be adjusted, and pci_set_max_read_req() returns the actual size set in
     bytes.  If the dev device is not a PCI-express device, pci_set_max_read_req() returns zero.

     The pci_get_powerstate() function returns the current power state of the device dev.  If the
     device does not support power management capabilities, then the default state of
     PCI_POWERSTATE_D0 is returned.  The following power states are defined by PCI:

     PCI_POWERSTATE_D0       State in which device is on and running.  It is receiving full power
                             from the system and delivering full functionality to the user.

     PCI_POWERSTATE_D1       Class-specific low-power state in which device context may or may
                             not be lost.  Buses in this state cannot do anything to the bus, to
                             force devices to lose context.

     PCI_POWERSTATE_D2       Class-specific low-power state in which device context may or may
                             not be lost.  Attains greater power savings than PCI_POWERSTATE_D1.
                             Buses in this state can cause devices to lose some context.  Devices
                             must be prepared for the bus to be in this state or higher.

     PCI_POWERSTATE_D3       State in which the device is off and not running.  Device context is
                             lost, and power from the device can be removed.

     PCI_POWERSTATE_UNKNOWN  State of the device is unknown.

     The pci_set_powerstate() function is used to transition the device dev to the PCI power
     state state.  If the device does not support power management capabilities or it does not
     support the specific power state state, then the function will fail with EOPNOTSUPP.

     The pci_iov_attach() function is used to advertise that the given device (and associated
     device driver) supports PCI Single-Root I/O Virtualization (SR-IOV).  A driver that supports
     SR-IOV must implement the PCI_IOV_INIT(9), PCI_IOV_ADD_VF(9) and PCI_IOV_UNINIT(9) methods.
     This function should be called during the DEVICE_ATTACH(9) method.  If this function returns
     an error, it is recommended that the device driver still successfully attaches, but runs
     with SR-IOV disabled.  The pf_schema and vf_schema parameters are used to define what
     device-specific configuration parameters the device driver accepts when SR-IOV is enabled
     for the Physical Function (PF) and for individual Virtual Functions (VFs) respectively.  See
     pci_iov_schema(9) for details on how to construct the schema.  If either the pf_schema or
     vf_schema is invalid or specifies parameter names that conflict with parameter names that
     are already in use, pci_iov_attach() will return an error and SR-IOV will not be available
     on the PF device.  If a driver does not accept configuration parameters for either the PF
     device or the VF devices, the driver must pass an empty schema for that device.  The SR-IOV
     infrastructure takes ownership of the pf_schema and vf_schema and is responsible for freeing
     them.  The driver must never free the schemas itself.

     The pci_iov_attach_name() function is a variant of pci_iov_attach() that allows the name of
     the associated character device in /dev/iov to be specified by fmt.  The pci_iov_attach()
     function uses the name of dev as the device name.

     The pci_iov_detach() function is used to advise the SR-IOV infrastructure that the driver
     for the given device is attempting to detach and that all SR-IOV resources for the device
     must be released.  This function must be called during the DEVICE_DETACH(9) method if
     pci_iov_attach() was successfully called on the device and pci_iov_detach() has not
     subsequently been called on the device and returned no error.  If this function returns an
     error, the DEVICE_DETACH(9) method must fail and return an error, as detaching the PF driver
     while VF devices are active would cause system instability.  This function is safe to call
     and will always succeed if pci_iov_attach() previously failed with an error on the given
     device, or if pci_iov_attach() was never called on the device.

     The pci_save_state() and pci_restore_state() functions can be used by a device driver to
     save and restore standard PCI config registers.  The pci_save_state() function must be
     invoked while the device has valid state before pci_restore_state() can be used.  If the
     device is not in the fully-powered state (PCI_POWERSTATE_D0) when pci_restore_state() is
     invoked, then the device will be transitioned to PCI_POWERSTATE_D0 before any config
     registers are restored.

     The pcie_flr() function requests a Function Level Reset (FLR) of dev.  If dev is not a PCI-
     express device or does not support Function Level Resets via the PCI-express device control
     register, false is returned.  Pending transactions are drained by disabling busmastering and
     calling pcie_wait_for_pending_transactions() before resetting the device.  The max_delay
     argument specifies the maximum timeout to wait for pending transactions as described for
     pcie_wait_for_pending_transactions().  If pcie_wait_for_pending_transactions() fails with a
     timeout and force is false, busmastering is re-enabled and false is returned.  If
     pcie_wait_for_pending_transactions() fails with a timeout and force is true, the device is
     reset despite the timeout.  After the reset has been requested, pcie_flr sleeps for at least
     100 milliseconds before returning true.  Note that pcie_flr does not save and restore any
     state around the reset.  The caller should save and restore state as needed.

   Message Signaled Interrupts
     Message Signaled Interrupts (MSI) and Enhanced Message Signaled Interrupts (MSI-X) are PCI
     capabilities that provide an alternate method for PCI devices to signal interrupts.  The
     legacy INTx interrupt is available to PCI devices as a SYS_RES_IRQ resource with a resource
     ID of zero.  MSI and MSI-X interrupts are available to PCI devices as one or more
     SYS_RES_IRQ resources with resource IDs greater than zero.  A driver must ask the PCI bus to
     allocate MSI or MSI-X interrupts using pci_alloc_msi() or pci_alloc_msix() before it can use
     MSI or MSI-X SYS_RES_IRQ resources.  A driver is not allowed to use the legacy INTx
     SYS_RES_IRQ resource if MSI or MSI-X interrupts have been allocated, and attempts to
     allocate MSI or MSI-X interrupts will fail if the driver is currently using the legacy INTx
     SYS_RES_IRQ resource.  A driver is only allowed to use either MSI or MSI-X, but not both.

     The pci_msi_count() function returns the maximum number of MSI messages supported by the
     device dev.  If the device does not support MSI, then pci_msi_count() returns zero.

     The pci_alloc_msi() function attempts to allocate *count MSI messages for the device dev.
     The pci_alloc_msi() function may allocate fewer messages than requested for various reasons
     including requests for more messages than the device dev supports, or if the system has a
     shortage of available MSI messages.  On success, *count is set to the number of messages
     allocated and pci_alloc_msi() returns zero.  The SYS_RES_IRQ resources for the allocated
     messages will be available at consecutive resource IDs beginning with one.  If
     pci_alloc_msi() is not able to allocate any messages, it returns an error.  Note that MSI
     only supports message counts that are powers of two; requests to allocate a non-power of two
     count of messages will fail.

     The pci_release_msi() function is used to release any allocated MSI or MSI-X messages back
     to the system.  If any MSI or MSI-X SYS_RES_IRQ resources are allocated by the driver or
     have a configured interrupt handler, this function will fail with EBUSY.  The
     pci_release_msi() function returns zero on success and an error on failure.

     The pci_msix_count() function returns the maximum number of MSI-X messages supported by the
     device dev.  If the device does not support MSI-X, then pci_msix_count() returns zero.

     The pci_msix_pba_bar() function returns the offset in configuration space of the Base
     Address Register (BAR) containing the MSI-X Pending Bit Array (PBA) for device dev.  The
     returned value can be used as the resource ID with bus_alloc_resource(9) and
     bus_release_resource(9) to allocate the BAR.  If the device does not support MSI-X, then
     pci_msix_pba_bar() returns -1.

     The pci_msix_table_bar() function returns the offset in configuration space of the BAR
     containing the MSI-X vector table for device dev.  The returned value can be used as the
     resource ID with bus_alloc_resource(9) and bus_release_resource(9) to allocate the BAR.  If
     the device does not support MSI-X, then pci_msix_table_bar() returns -1.

     The pci_alloc_msix() function attempts to allocate *count MSI-X messages for the device dev.
     The pci_alloc_msix() function may allocate fewer messages than requested for various reasons
     including requests for more messages than the device dev supports, or if the system has a
     shortage of available MSI-X messages.  On success, *count is set to the number of messages
     allocated and pci_alloc_msix() returns zero.  For MSI-X messages, the resource ID for each
     SYS_RES_IRQ resource identifies the index in the MSI-X table of the corresponding message.
     A resource ID of one maps to the first index of the MSI-X table; a resource ID two
     identifies the second index in the table, etc.  The pci_alloc_msix() function assigns the
     *count messages allocated to the first *count table indices.  If pci_alloc_msix() is not
     able to allocate any messages, it returns an error.  Unlike MSI, MSI-X does not require
     message counts that are powers of two.

     The BARs containing the MSI-X vector table and PBA must be allocated via
     bus_alloc_resource(9) before calling pci_alloc_msix() and must not be released until after
     calling pci_release_msi().  Note that the vector table and PBA may be stored in the same BAR
     or in different BARs.

     The pci_pending_msix() function examines the dev device's PBA to determine the pending
     status of the MSI-X message at table index index.  If the indicated message is pending, this
     function returns a non-zero value; otherwise, it returns zero.  Passing an invalid index to
     this function will result in undefined behavior.

     As mentioned in the description of pci_alloc_msix(), MSI-X messages are initially assigned
     to the first N table entries.  A driver may use a different distribution of available
     messages to table entries via the pci_remap_msix() function.  Note that this function must
     be called after a successful call to pci_alloc_msix() but before any of the SYS_RES_IRQ
     resources are allocated.  The pci_remap_msix() function returns zero on success, or an error
     on failure.

     The vectors array should contain count message vectors.  The array maps directly to the MSI-
     X table in that the first entry in the array specifies the message used for the first entry
     in the MSI-X table, the second entry in the array corresponds to the second entry in the
     MSI-X table, etc.  The vector value in each array index can either be zero to indicate that
     no message should be assigned to the corresponding MSI-X table entry, or it can be a number
     from one to N (where N is the count returned from the previous call to pci_alloc_msix()) to
     indicate which of the allocated messages should be assigned to the corresponding MSI-X table
     entry.

     If pci_remap_msix() succeeds, each MSI-X table entry with a non-zero vector will have an
     associated SYS_RES_IRQ resource whose resource ID corresponds to the table index as
     described above for pci_alloc_msix().  MSI-X table entries that with a vector of zero will
     not have an associated SYS_RES_IRQ resource.  Additionally, if any of the original messages
     allocated by pci_alloc_msix() are not used in the new distribution of messages in the MSI-X
     table, they will be released automatically.  Note that if a driver wishes to use fewer
     messages than were allocated by pci_alloc_msix(), the driver must use a single, contiguous
     range of messages beginning with one in the new distribution.  The pci_remap_msix() function
     will fail if this condition is not met.

   Device Events
     The pci_add_device event handler is invoked every time a new PCI device is added to the
     system.  This includes the creation of Virtual Functions via SR-IOV.

     The pci_delete_device event handler is invoked every time a PCI device is removed from the
     system.

     Both event handlers pass the device_t object of the relevant PCI device as dev to each
     callback function.  Both event handlers are invoked while dev is unattached but with valid
     instance variables.

SEE ALSO

     pci(4), pciconf(8), bus_alloc_resource(9), bus_dma(9), bus_release_resource(9),
     bus_setup_intr(9), bus_teardown_intr(9), devclass(9), device(9), driver(9), eventhandler(9),
     rman(9)

     "NewBus", FreeBSD Developers' Handbook,
     https://www.FreeBSD.org/doc/en_US.ISO8859-1/books/developers-handbook/.

     Shanley and Anderson, PCI System Architecture, Addison-Wesley, 2nd Edition, ISBN
     0-201-30974-2.

AUTHORS

     This manual page was written by Bruce M Simpson <bms@FreeBSD.org> and John Baldwin
     <jhb@FreeBSD.org>.

BUGS

     The kernel PCI code has a number of references to “slot numbers”.  These do not refer to the
     geographic location of PCI devices, but to the device number assigned by the combination of
     the PCI IDSEL mechanism and the platform firmware.  This should be taken note of when
     working with the kernel PCI code.

     The PCI bus driver should allocate the MSI-X vector table and PBA internally as necessary
     rather than requiring the caller to do so.