freebsd-skq/sys/dev/pci/pcib_if.m
jhb 3624354c54 Expand the MSI/MSI-X API to address some deficiencies in the MSI-X support.
- First off, device drivers really do need to know if they are allocating
  MSI or MSI-X messages.  MSI requires allocating powerof2() messages for
  example where MSI-X does not.  To address this, split out the MSI-X
  support from pci_msi_count() and pci_alloc_msi() into new driver-visible
  functions pci_msix_count() and pci_alloc_msix().  As a result,
  pci_msi_count() now just returns a count of the max supported MSI
  messages for the device, and pci_alloc_msi() only tries to allocate MSI
  messages.  To get a count of the max supported MSI-X messages, use
  pci_msix_count().  To allocate MSI-X messages, use pci_alloc_msix().
  pci_release_msi() still handles both MSI and MSI-X messages, however.
  As a result of this change, drivers using the existing API will only
  use MSI messages and will no longer try to use MSI-X messages.
- Because MSI-X allows for each message to have its own data and address
  values (and thus does not require all of the messages to have their
  MD vectors allocated as a group), some devices allow for "sparse" use
  of MSI-X message slots.  For example, if a device supports 8 messages
  but the OS is only able to allocate 2 messages, the device may make the
  best use of 2 IRQs if it enables the messages at slots 1 and 4 rather
  than default of using the first N slots (or indicies) at 1 and 2.  To
  support this, add a new pci_remap_msix() function that a driver may call
  after a successful pci_alloc_msix() (but before allocating any of the
  SYS_RES_IRQ resources) to allow the allocated IRQ resources to be
  assigned to different message indices.  For example, from the earlier
  example, after pci_alloc_msix() returned a value of 2, the driver would
  call pci_remap_msix() passing in array of integers { 1, 4 } as the
  new message indices to use.  The rid's for the SYS_RES_IRQ resources
  will always match the message indices.  Thus, after the call to
  pci_remap_msix() the driver would be able to access the first message
  in slot 1 at SYS_RES_IRQ rid 1, and the second message at slot 4 at
  SYS_RES_IRQ rid 4.  Note that the message slots/indices are 1-based
  rather than 0-based so that they will always correspond to the rid
  values (SYS_RES_IRQ rid 0 is reserved for the legacy INTx interrupt).
  To support this API, a new PCIB_REMAP_MSIX() method was added to the
  pcib interface to change the message index for a single IRQ.

Tested by:	scottl
2007-01-22 21:48:44 +00:00

146 lines
3.7 KiB
Objective-C

#-
# Copyright (c) 2000 Doug Rabson
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
# $FreeBSD$
#
#include <sys/bus.h>
#include <dev/pci/pcivar.h>
INTERFACE pcib;
CODE {
static int
null_route_interrupt(device_t pcib, device_t dev, int pin)
{
return (PCI_INVALID_IRQ);
}
};
#
# Return the number of slots on the attached PCI bus.
#
METHOD int maxslots {
device_t dev;
};
#
# Read configuration space on the PCI bus. The bus, slot and func
# arguments determine the device which is being read and the reg
# argument is a byte offset into configuration space for that
# device. The width argument (which should be 1, 2 or 4) specifies how
# many byte of configuration space to read from that offset.
#
METHOD u_int32_t read_config {
device_t dev;
u_int bus;
u_int slot;
u_int func;
u_int reg;
int width;
};
#
# Write configuration space on the PCI bus. The bus, slot and func
# arguments determine the device which is being written and the reg
# argument is a byte offset into configuration space for that
# device. The value field is written to the configuration space, with
# the number of bytes written depending on the width argument.
#
METHOD void write_config {
device_t dev;
u_int bus;
u_int slot;
u_int func;
u_int reg;
u_int32_t value;
int width;
};
#
# Route an interrupt. Returns a value suitable for stuffing into
# a device's interrupt register.
#
METHOD int route_interrupt {
device_t pcib;
device_t dev;
int pin;
} DEFAULT null_route_interrupt;
#
# Allocate 'count' MSI messsages mapped onto 'count' IRQs. 'irq' points
# to an array of at least 'count' ints. The max number of messages this
# device supports is included so that the MD code can take that into
# account when assigning resources so that the proper number of low bits
# are clear in the resulting message data value.
#
METHOD int alloc_msi {
device_t pcib;
device_t dev;
int count;
int maxcount;
int *irqs;
};
#
# Release 'count' MSI message mapped onto 'count' IRQs stored in the
# array pointed to by 'irq'.
#
METHOD int release_msi {
device_t pcib;
device_t dev;
int count;
int *irqs;
};
#
# Allocate a single MSI-X message mapped onto '*irq'.
#
METHOD int alloc_msix {
device_t pcib;
device_t dev;
int index;
int *irq;
};
#
# Remap a single MSI-X message to a different index.
#
METHOD int remap_msix {
device_t pcib;
device_t dev;
int index;
int irq;
};
#
# Release a single MSI-X message mapped onto 'irq'.
#
METHOD int release_msix {
device_t pcib;
device_t dev;
int irq;
};