这几天发现在Redhat AS6.5 X86_64下用outl(index, 0xcf8)和inl(0xcfc)下读取PCIe配置空间是系统有时性的会hang， 于是去寻找解决方案，首先想到的是用/dev/port这种方案去替代，折腾了半天发现不行，后来想到为什么不用lspci的方法了，结果就成功了，如下为分享。
1．基本介绍
Lspci的工具包名为pciutils， 是由捷克的大伽Martin Mares 开发的,目前最新的版本为3.5.1, 你可以通过mj@ucw.cz 联系他, 他的个人主页为http://mj.ucw.cz/, 在上面可以找到他的联系方式。
Lspci支持众多OS，
Linux (via /sys/bus/pci, /proc/bus/pci or i386 ports)
FreeBSD (via /dev/pci)
NetBSD (via libpci)
OpenBSD (via /dev/pci)
GNU/kFreeBSD (via /dev/pci)
Solaris/i386 (direct port access)
Aix (via /dev/pci and odmget)
GNU Hurd (direct port access)
Windows (direct port access, see README.Windows for caveats)
CYGWIN (direct port access)
BeOS (via syscalls)
Haiku (via /dev/misc/poke)
Darwin (via IOKit)
当然我们最关心的Linux.
2．下载
你可以从ftp://atrey.karlin.mff.cuni.cz/pub/linux/pci/ 下载到最新的pciutils，下载后将pciutils-3.5.1.tar.gz解压。然后进入目录运行make进行编译， 编译后你会看到如下目录。
3．Libpci库
进入lib目录， 就会看到生成了一个libpci.a的静态库，这个库你是可以调用的，如果想调用动态库，只需要修改Makefile， 将SHARED参数改为yes即可
SHARED=yes
#make clean
#make
就会有libpci.so.3.5.1生成，如果嫌后面的版本麻烦，可以将其直接改名为libpci.so.
实际上无论是lspci还是setpci都是调用libpci这个库的。
4. libpci库的调用
首先将libpci.so加到makefile中去，以下为一个例子。
LIB+=-lpthread -ldl ../../lib/libpci.so
以下是具体的调用例子：
将lib目录下的头文件全部copy到/usr/include/pci目录下，有些Linux系统是没有pci目录的，需要创建一个。
#include <pci/pci.h>
bool PCIe::getPCIConfig(PCI_CONFIG *pci_cfg, unsigned char BusNum, unsigned char DevNum, unsigned char FuncNum)
{
bool bRet = true;
unsigned int* pPCIConfig = (unsigned int*)pci_cfg;
int i,j;
unsigned char value[256];
memset(value, 0, sizeof(value));
struct pci_access *pacc;
struct pci_dev *dev;
pacc = pci_alloc(); /* Get the pci_access structure */
/* Set all options you want -- here we stick with the defaults */
pci_init(pacc); /* Initialize the PCI library */
pci_scan_bus(pacc); /* We want to get the list of devices */
for (dev=pacc->devices; dev; dev=dev->next) /* Iterate over all devices */
{
if(! pci_read_block(dev, 0, value, 256))
{
printf("Get PCIE configuration space block fail ");
break;
}
if((BusNum == dev->bus) && (DevNum == dev->dev) && (FuncNum == dev->func))
{
for(i=0, j=0;i<64, j<256;i++, j+=4)
{
pPCIConfig[i] = value[j] | (value[j+1] <<8) | (value[j+2] <<16) | (value[j+3] <<24);
// printf("%d: %04x ", i, pPCIConfig[i] );
if (i == 0 && ((pPCIConfig[i] == 0xFFFFFFFF) || ((pPCIConfig[i]&0xFFFF) == 0L)))
{
bRet = false;
break;
}
}
break;
}
}
pci_cleanup(pacc); /* Close everything */
return bRet;
}
调用的函数都在pci.h中可以参考如下。
/*
* The PCI Library
*
* Copyright (c) 1997--2016 Martin Mares <mj@ucw.cz>
*
* Can be freely distributed and used under the terms of the GNU GPL.
*/
#ifndef _PCI_LIB_H
#define _PCI_LIB_H
#ifndef PCI_CONFIG_H
#include "config.h"
#endif
#include "header.h"
#include "types.h"
#define PCI_LIB_VERSION 0x030501
#ifndef PCI_ABI
#define PCI_ABI
#endif
/*
* PCI Access Structure
*/
struct pci_methods;
enum pci_access_type {
/* Known access methods, remember to update access.c as well */
PCI_ACCESS_AUTO, /* Autodetection */
PCI_ACCESS_SYS_BUS_PCI, /* Linux /sys/bus/pci */
PCI_ACCESS_PROC_BUS_PCI, /* Linux /proc/bus/pci */
PCI_ACCESS_I386_TYPE1, /* i386 ports, type 1 */
PCI_ACCESS_I386_TYPE2, /* i386 ports, type 2 */
PCI_ACCESS_FBSD_DEVICE, /* FreeBSD /dev/pci */
PCI_ACCESS_AIX_DEVICE, /* /dev/pci0, /dev/bus0, etc. */
PCI_ACCESS_NBSD_LIBPCI, /* NetBSD libpci */
PCI_ACCESS_OBSD_DEVICE, /* OpenBSD /dev/pci */
PCI_ACCESS_DUMP, /* Dump file */
PCI_ACCESS_DARWIN, /* Darwin */
PCI_ACCESS_MAX
};
struct pci_access {
/* Options you can change: */
unsigned int method; /* Access method */
int writeable; /* Open in read/write mode */
int buscentric; /* Bus-centric view of the world */
char *id_file_name; /* Name of ID list file (use pci_set_name_list_path()) */
int free_id_name; /* Set if id_file_name is malloced */
int numeric_ids; /* Enforce PCI_LOOKUP_NUMERIC (>1 => PCI_LOOKUP_MIXED) */
unsigned int id_lookup_mode; /* pci_lookup_mode flags which are set automatically */
/* Default: PCI_LOOKUP_CACHE */
int debugging; /* Turn on debugging messages */
/* Functions you can override: */
void (*error)(char *msg, ...) PCI_PRINTF(1,2); /* Write error message and quit */
void (*warning)(char *msg, ...) PCI_PRINTF(1,2); /* Write a warning message */
void (*debug)(char *msg, ...) PCI_PRINTF(1,2); /* Write a debugging message */
struct pci_dev *devices; /* Devices found on this bus */
/* Fields used internally: */
struct pci_methods *methods;
struct pci_param *params;
struct id_entry **id_hash; /* names.c */
struct id_bucket *current_id_bucket;
int id_load_failed;
int id_cache_status; /* 0=not read, 1=read, 2=dirty */
struct udev *id_udev; /* names-hwdb.c */
struct udev_hwdb *id_udev_hwdb;
int fd; /* proc/sys: fd for config space */
int fd_rw; /* proc/sys: fd opened read-write */
int fd_pos; /* proc/sys: current position */
int fd_vpd; /* sys: fd for VPD */
struct pci_dev *cached_dev; /* proc/sys: device the fds are for */
};
/* Initialize PCI access */
struct pci_access *pci_alloc(void) PCI_ABI;
void pci_init(struct pci_access *) PCI_ABI;
void pci_cleanup(struct pci_access *) PCI_ABI;
/* Scanning of devices */
void pci_scan_bus(struct pci_access *acc) PCI_ABI;
struct pci_dev *pci_get_dev(struct pci_access *acc, int domain, int bus, int dev, int func) PCI_ABI; /* Raw access to specified device */
void pci_free_dev(struct pci_dev *) PCI_ABI;
/* Names of access methods */
int pci_lookup_method(char *name) PCI_ABI; /* Returns -1 if not found */
char *pci_get_method_name(int index) PCI_ABI; /* Returns "" if unavailable, NULL if index out of range */
/*
* Named parameters
*/
struct pci_param {
struct pci_param *next; /* Please use pci_walk_params() for traversing the list */
char *param; /* Name of the parameter */
char *value; /* Value of the parameter */
int value_malloced; /* used internally */
char *help; /* Explanation of the parameter */
};
char *pci_get_param(struct pci_access *acc, char *param) PCI_ABI;
int pci_set_param(struct pci_access *acc, char *param, char *value) PCI_ABI; /* 0 on success, -1 if no such parameter */
/* To traverse the list, call pci_walk_params repeatedly, first with prev=NULL, and do not modify the parameters during traversal. */
struct pci_param *pci_walk_params(struct pci_access *acc, struct pci_param *prev) PCI_ABI;
/*
* Devices
*/
struct pci_dev {
struct pci_dev *next; /* Next device in the chain */
u16 domain_16; /* 16-bit version of the PCI domain for backward compatibility */
/* 0xffff if the real domain doesn't fit in 16 bits */
u8 bus, dev, func; /* Bus inside domain, device and function */
/* These fields are set by pci_fill_info() */
int known_fields; /* Set of info fields already known */
u16 vendor_id, device_id; /* Identity of the device */
u16 device_class; /* PCI device class */
int irq; /* IRQ number */
pciaddr_t base_addr[6]; /* Base addresses including flags in lower bits */
pciaddr_t size[6]; /* Region sizes */
pciaddr_t rom_base_addr; /* Expansion ROM base address */
pciaddr_t rom_size; /* Expansion ROM size */
struct pci_cap *first_cap; /* List of capabilities */
char *phy_slot; /* Physical slot */
char *module_alias; /* Linux kernel module alias */
char *label; /* Device name as exported by BIOS */
int numa_node; /* NUMA node */
pciaddr_t flags[6]; /* PCI_IORESOURCE_* flags for regions */
pciaddr_t rom_flags; /* PCI_IORESOURCE_* flags for expansion ROM */
int domain; /* PCI domain (host bridge) */
/* Fields used internally: */
struct pci_access *access;
struct pci_methods *methods;
u8 *cache; /* Cached config registers */
int cache_len;
int hdrtype; /* Cached low 7 bits of header type, -1 if unknown */
void *aux; /* Auxillary data */
};
#define PCI_ADDR_IO_MASK (~(pciaddr_t) 0x3)
#define PCI_ADDR_MEM_MASK (~(pciaddr_t) 0xf)
#define PCI_ADDR_FLAG_MASK 0xf
u8 pci_read_byte(struct pci_dev *, int pos) PCI_ABI; /* Access to configuration space */
u16 pci_read_word(struct pci_dev *, int pos) PCI_ABI;
u32 pci_read_long(struct pci_dev *, int pos) PCI_ABI;
int pci_read_block(struct pci_dev *, int pos, u8 *buf, int len) PCI_ABI;
int pci_read_vpd(struct pci_dev *d, int pos, u8 *buf, int len) PCI_ABI;
int pci_write_byte(struct pci_dev *, int pos, u8 data) PCI_ABI;
int pci_write_word(struct pci_dev *, int pos, u16 data) PCI_ABI;
int pci_write_long(struct pci_dev *, int pos, u32 data) PCI_ABI;
int pci_write_block(struct pci_dev *, int pos, u8 *buf, int len) PCI_ABI;
int pci_fill_info(struct pci_dev *, int flags) PCI_ABI; /* Fill in device information */
#define PCI_FILL_IDENT 0x0001
#define PCI_FILL_IRQ 0x0002
#define PCI_FILL_BASES 0x0004
#define PCI_FILL_ROM_BASE 0x0008
#define PCI_FILL_SIZES 0x0010
#define PCI_FILL_CLASS 0x0020
#define PCI_FILL_CAPS 0x0040
#define PCI_FILL_EXT_CAPS 0x0080
#define PCI_FILL_PHYS_SLOT 0x0100
#define PCI_FILL_MODULE_ALIAS 0x0200
#define PCI_FILL_LABEL 0x0400
#define PCI_FILL_NUMA_NODE 0x0800
#define PCI_FILL_IO_FLAGS 0x1000
#define PCI_FILL_RESCAN 0x00010000
void pci_setup_cache(struct pci_dev *, u8 *cache, int len) PCI_ABI;
/*
* Capabilities
*/
struct pci_cap {
struct pci_cap *next;
u16 id; /* PCI_CAP_ID_xxx */
u16 type; /* PCI_CAP_xxx */
unsigned int addr; /* Position in the config space */
};
#define PCI_CAP_NORMAL 1 /* Traditional PCI capabilities */
#define PCI_CAP_EXTENDED 2 /* PCIe extended capabilities */
struct pci_cap *pci_find_cap(struct pci_dev *, unsigned int id, unsigned int type) PCI_ABI;
/*
* Filters
*/
struct pci_filter {
int domain, bus, slot, func; /* -1 = ANY */
int vendor, device, device_class;
int rfu[3];
};
void pci_filter_init(struct pci_access *, struct pci_filter *) PCI_ABI;
char *pci_filter_parse_slot(struct pci_filter *, char *) PCI_ABI;
char *pci_filter_parse_id(struct pci_filter *, char *) PCI_ABI;
int pci_filter_match(struct pci_filter *, struct pci_dev *) PCI_ABI;
/*
* Conversion of PCI ID's to names (according to the pci.ids file)
*
* Call pci_lookup_name() to identify different types of ID's:
*
* VENDOR (vendorID) -> vendor
* DEVICE (vendorID, deviceID) -> device
* VENDOR | DEVICE (vendorID, deviceID) -> combined vendor and device
* SUBSYSTEM | VENDOR (subvendorID) -> subsystem vendor
* SUBSYSTEM | DEVICE (vendorID, deviceID, subvendorID, subdevID) -> subsystem device
* SUBSYSTEM | VENDOR | DEVICE (vendorID, deviceID, subvendorID, subdevID) -> combined subsystem v+d
* SUBSYSTEM | ... (-1, -1, subvendorID, subdevID) -> generic subsystem
* CLASS (classID) -> class
* PROGIF (classID, progif) -> programming interface
*/
char *pci_lookup_name(struct pci_access *a, char *buf, int size, int flags, ...) PCI_ABI;
int pci_load_name_list(struct pci_access *a) PCI_ABI; /* Called automatically by pci_lookup_*() when needed; returns success */
void pci_free_name_list(struct pci_access *a) PCI_ABI; /* Called automatically by pci_cleanup() */
void pci_set_name_list_path(struct pci_access *a, char *name, int to_be_freed) PCI_ABI;
void pci_id_cache_flush(struct pci_access *a) PCI_ABI;
enum pci_lookup_mode {
PCI_LOOKUP_VENDOR = 1, /* Vendor name (args: vendorID) */
PCI_LOOKUP_DEVICE = 2, /* Device name (args: vendorID, deviceID) */
PCI_LOOKUP_CLASS = 4, /* Device class (args: classID) */
PCI_LOOKUP_SUBSYSTEM = 8,
PCI_LOOKUP_PROGIF = 16, /* Programming interface (args: classID, prog_if) */
PCI_LOOKUP_NUMERIC = 0x10000, /* Want only formatted numbers; default if access->numeric_ids is set */
PCI_LOOKUP_NO_NUMBERS = 0x20000, /* Return NULL if not found in the database; default is to print numerically */
PCI_LOOKUP_MIXED = 0x40000, /* Include both numbers and names */
PCI_LOOKUP_NETWORK = 0x80000, /* Try to resolve unknown ID's by DNS */
PCI_LOOKUP_SKIP_LOCAL = 0x100000, /* Do not consult local database */
PCI_LOOKUP_CACHE = 0x200000, /* Consult the local cache before using DNS */
PCI_LOOKUP_REFRESH_CACHE = 0x400000, /* Forget all previously cached entries, but still allow updating the cache */
PCI_LOOKUP_NO_HWDB = 0x800000, /* Do not ask udev's hwdb */
};
#endif