MFC 290414,290415:

Additional PCI helper functions.

290414:
Add helper routines for PCI device drivers to read, write, and modify
PCI-Express capability registers (that is, PCI config registers in the
standard PCI config space belonging to the PCI-Express capability
register set).

Note that all of the current PCI-e registers are either 16 or 32-bits,
so only widths of 2 or 4 bytes are supported.

290415:
Add a new helper function for PCI devices to locate the upstream
PCI-express root port of a given PCI device.

2 files changed, 77 insertions, 3 deletions

diff --git a/share/man/man9/Makefile b/share/man/man9/Makefile
index 69bf839..d9156c0 100644
--- a/share/man/man9/Makefile
+++ b/share/man/man9/Makefile
@@ -1014,6 +1014,7 @@ MLINKS+=pci.9 pci_alloc_msi.9 \
 	pci.9 pci_find_device.9 \
 	pci.9 pci_find_extcap.9 \
 	pci.9 pci_find_htcap.9 \
+	pci.9 pci_find_pcie_root_port.9 \
 	pci.9 pci_get_max_read_req.9 \
 	pci.9 pci_get_powerstate.9 \
 	pci.9 pci_get_vpd_ident.9 \
@@ -1028,7 +1029,10 @@ MLINKS+=pci.9 pci_alloc_msi.9 \
 	pci.9 pci_save_state.9 \
 	pci.9 pci_set_powerstate.9 \
 	pci.9 pci_set_max_read_req.9 \
-	pci.9 pci_write_config.9
+	pci.9 pci_write_config.9 \
+	pci.9 pcie_adjust_config.9 \
+	pci.9 pcie_read_config.9 \
+	pci.9 pcie_write_config.9 \
 MLINKS+=pfil.9 pfil_add_hook.9 \
 	pfil.9 pfil_hook_get.9 \
 	pfil.9 pfil_remove_hook.9
diff --git a/share/man/man9/pci.9 b/share/man/man9/pci.9
index 28bae85..6599e28 100644
--- a/share/man/man9/pci.9
+++ b/share/man/man9/pci.9
@@ -25,7 +25,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd March 5, 2012
+.Dd November 5, 2015
 .Dt PCI 9
 .Os
 .Sh NAME
@@ -42,6 +42,7 @@
 .Nm pci_find_device ,
 .Nm pci_find_extcap ,
 .Nm pci_find_htcap ,
+.Nm pci_find_pcie_root_port ,
 .Nm pci_get_max_read_req ,
 .Nm pci_get_powerstate ,
 .Nm pci_get_vpd_ident ,
@@ -56,7 +57,10 @@
 .Nm pci_save_state ,
 .Nm pci_set_max_read_req ,
 .Nm pci_set_powerstate ,
-.Nm pci_write_config
+.Nm pci_write_config ,
+.Nm pcie_adjust_config ,
+.Nm pcie_read_config ,
+.Nm pcie_write_config
 .Nd PCI bus interface
 .Sh SYNOPSIS
 .In sys/bus.h
@@ -86,6 +90,8 @@
 .Fn pci_find_extcap "device_t dev" "int capability" "int *capreg"
 .Ft int
 .Fn pci_find_htcap "device_t dev" "int capability" "int *capreg"
+.Ft device_t
+.Fn pci_find_pcie_root_port "device_t dev"
 .Ft int
 .Fn pci_get_max_read_req "device_t dev"
 .Ft int
@@ -116,6 +122,18 @@
 .Fn pci_set_powerstate "device_t dev" "int state"
 .Ft void
 .Fn pci_write_config "device_t dev" "int reg" "uint32_t val" "int width"
+.Ft uint32_t
+.Fo pcie_adjust_config
+.Fa "device_t dev"
+.Fa "int reg"
+.Fa "uint32_t mask"
+.Fa "uint32_t val"
+.Fa "int width"
+.Fc
+.Ft uint32_t
+.Fn pcie_read_config "device_t dev" "int reg" "int width"
+.Ft void
+.Fn pcie_write_config "device_t dev" "int reg" "uint32_t val" "int width"
 .Sh DESCRIPTION
 The
 .Nm
@@ -152,6 +170,48 @@ with
 .Fa width
 specifying the size of the access.
 .Pp
+The
+.Fn pcie_adjust_config
+function is used to modify the value of a register in the PCI-express
+capability register set of device
+.Fa dev .
+The offset
+.Fa reg
+specifies a relative offset in the register set with
+.Fa width
+specifying the size of the access.
+The new value of the register is computed by modifying bits set in
+.Fa mask
+to the value in
+.Fa val .
+Any bits not specified in
+.Fa mask
+are preserved.
+The previous value of the register is returned.
+.Pp
+The
+.Fn pcie_read_config
+function is used to read the value of a register in the PCI-express
+capability register set of device
+.Fa dev .
+The offset
+.Fa reg
+specifies a relative offset in the register set with
+.Fa width
+specifying the size of the access.
+.Pp
+The
+.Fn pcie_write_config
+function is used to write the value
+.Fa val
+to a register in the PCI-express capability register set of device
+.Fa dev .
+The offset
+.Fa reg
+specifies a relative offset in the register set with
+.Fa width
+specifying the size of the access.
+.Pp
 .Em NOTE :
 Device drivers should only use these functions for functionality that
 is not available via another
@@ -274,6 +334,16 @@ If the capability is not found or the device is not a HyperTransport device,
 returns an error.
 .Pp
 The
+.Fn pci_find_pcie_root_port
+function walks up the PCI device hierarchy to locate the PCI-express root
+port upstream of
+.Fa dev .
+If a root port is not found,
+.Fn pci_find_pcie_root_port
+returns
+.Dv NULL .
+.Pp
+The
 .Fn pci_get_vpd_ident
 function is used to fetch a device's Vital Product Data
 .Pq VPD