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[linux] Add support for accessing PCI configuration space via /proc/bus/pci
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
185
src/interface/linux/linux_pci.c
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185
src/interface/linux/linux_pci.c
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/*
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* Copyright (C) 2013 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <stdio.h>
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#include <errno.h>
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#include <byteswap.h>
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#include <linux_api.h>
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#include <ipxe/linux.h>
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#include <ipxe/pci.h>
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/** @file
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*
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* iPXE PCI API for Linux
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*
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*/
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/**
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* Open PCI configuration space
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*
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* @v pci PCI device
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* @v flags Access mode flags
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* @v where Address within configuration space
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* @ret fd File handle, or negative error
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*/
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static int linux_pci_open ( struct pci_device *pci, int flags,
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unsigned long where ) {
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char filename[ 22 /* "/proc/bus/pci/xx/xx.x" + NUL */ ];
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int fd;
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int rc;
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/* Construct filename */
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snprintf ( filename, sizeof ( filename ), "/proc/bus/pci/%02x/%02x.%x",
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PCI_BUS ( pci->busdevfn ), PCI_SLOT ( pci->busdevfn ),
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PCI_FUNC ( pci->busdevfn ) );
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/* Open file */
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fd = linux_open ( filename, flags );
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if ( fd < 0 ) {
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DBGC ( pci, "PCI could not open %s: %s\n", filename,
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linux_strerror ( linux_errno ) );
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rc = -ELINUX ( linux_errno );
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goto err_open;
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}
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/* Seek to location */
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if ( linux_lseek ( fd, where, SEEK_SET ) < 0 ) {
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DBGC ( pci, "PCI could not seek to %s offset %#02lx: %s\n",
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filename, where, linux_strerror ( linux_errno ) );
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rc = -ELINUX ( linux_errno );
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goto err_seek;
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}
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return fd;
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err_seek:
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linux_close ( fd );
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err_open:
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return rc;
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}
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/**
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* Read from PCI configuration space
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*
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* @v pci PCI device
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* @v where Address within configuration space
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* @v value Data buffer
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* @v len Length to read
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* @ret rc Return status code
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*/
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int linux_pci_read ( struct pci_device *pci, unsigned long where,
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unsigned long *value, size_t len ) {
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uint32_t tmp = 0;
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int fd;
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int check_len;
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int rc;
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/* Return "missing device" in case of error */
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*value = -1UL;
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/* Open configuration space */
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fd = linux_pci_open ( pci, O_RDONLY, where );
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if ( fd < 0 ) {
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rc = fd;
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goto err_open;
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}
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/* Read value */
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check_len = linux_read ( fd, &tmp, len );
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if ( check_len < 0 ) {
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DBGC ( pci, "PCI could not read from " PCI_FMT " %#02lx+%#zx: "
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"%s\n", PCI_ARGS ( pci ), where, len,
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linux_strerror ( linux_errno ) );
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rc = -ELINUX ( linux_errno );
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goto err_read;
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}
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if ( ( size_t ) check_len != len ) {
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DBGC ( pci, "PCI read only %#x bytes from " PCI_FMT
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" %#02lx+%#zx\n", check_len, PCI_ARGS ( pci ),
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where, len );
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rc = -EIO;
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goto err_read;
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}
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/* Return value */
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*value = le32_to_cpu ( tmp );
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/* Success */
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rc = 0;
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err_read:
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linux_close ( fd );
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err_open:
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return rc;
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}
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/**
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* Write to PCI configuration space
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*
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* @v pci PCI device
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* @v where Address within configuration space
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* @v value Value to write
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* @v len Length of value
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* @ret rc Return status code
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*/
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int linux_pci_write ( struct pci_device *pci, unsigned long where,
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unsigned long value, size_t len ) {
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uint32_t tmp;
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int fd;
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int check_len;
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int rc;
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/* Open configuration space */
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fd = linux_pci_open ( pci, O_WRONLY, where );
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if ( fd < 0 ) {
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rc = fd;
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goto err_open;
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}
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/* Prepare value for writing */
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tmp = cpu_to_le32 ( value );
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assert ( len <= sizeof ( tmp ) );
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/* Write value */
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check_len = linux_write ( fd, &tmp, len );
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if ( check_len < 0 ) {
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DBGC ( pci, "PCI could not write to " PCI_FMT " %#02lx+%#zx: "
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"%s\n", PCI_ARGS ( pci ), where, len,
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linux_strerror ( linux_errno ) );
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rc = -ELINUX ( linux_errno );
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goto err_write;
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}
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if ( ( size_t ) check_len != len ) {
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DBGC ( pci, "PCI wrote only %#x bytes to " PCI_FMT
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" %#02lx+%#zx\n", check_len, PCI_ARGS ( pci ),
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where, len );
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rc = -EIO;
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goto err_write;
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}
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/* Success */
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rc = 0;
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err_write:
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linux_close ( fd );
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err_open:
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return rc;
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}
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