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27 * Access PCI subsystem using Linux's sysfs interface. This interface is
28 * available starting somewhere in the late 2.5.x kernel phase, and is the
29 * prefered method on all 2.6.x kernels.
31 * \author Ian Romanick <idr@us.ibm.com>
40 #include <sys/types.h>
51 #include <sys/ioctl.h>
54 #include "pciaccess.h"
55 #include "pciaccess_private.h"
56 #include "linux_devmem.h"
58 static int pci_device_linux_sysfs_read_rom( struct pci_device * dev,
61 static int pci_device_linux_sysfs_probe( struct pci_device * dev );
63 static int pci_device_linux_sysfs_map_range(struct pci_device *dev,
64 struct pci_device_mapping *map);
66 static int pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
67 struct pci_device_mapping *map);
69 static int pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
70 pciaddr_t offset, pciaddr_t size, pciaddr_t * bytes_read );
72 static int pci_device_linux_sysfs_write( struct pci_device * dev,
73 const void * data, pciaddr_t offset, pciaddr_t size,
74 pciaddr_t * bytes_wrtten );
76 static const struct pci_system_methods linux_sysfs_methods = {
78 .destroy_device = NULL,
79 .read_rom = pci_device_linux_sysfs_read_rom,
80 .probe = pci_device_linux_sysfs_probe,
81 .map_range = pci_device_linux_sysfs_map_range,
82 .unmap_range = pci_device_linux_sysfs_unmap_range,
84 .read = pci_device_linux_sysfs_read,
85 .write = pci_device_linux_sysfs_write,
87 .fill_capabilities = pci_fill_capabilities_generic
90 #define SYS_BUS_PCI "/sys/bus/pci/devices"
93 static int populate_entries(struct pci_system * pci_sys);
97 * Attempt to access PCI subsystem using Linux's sysfs interface.
100 pci_system_linux_sysfs_create( void )
106 /* If the directory "/sys/bus/pci/devices" exists, then the PCI subsystem
107 * can be accessed using this interface.
110 if ( stat( SYS_BUS_PCI, & st ) == 0 ) {
111 pci_sys = calloc( 1, sizeof( struct pci_system ) );
112 if ( pci_sys != NULL ) {
113 pci_sys->methods = & linux_sysfs_methods;
114 err = populate_entries(pci_sys);
125 pci_sys->mtrr_fd = open("/proc/mtrr", O_WRONLY);
133 * Filter out the names "." and ".." from the scanned sysfs entries.
135 * \param d Directory entry being processed by \c scandir.
138 * Zero if the entry name matches either "." or "..", non-zero otherwise.
140 * \sa scandir, populate_entries
143 scan_sys_pci_filter( const struct dirent * d )
145 return !((strcmp( d->d_name, "." ) == 0)
146 || (strcmp( d->d_name, ".." ) == 0));
151 populate_entries( struct pci_system * p )
153 struct dirent ** devices;
159 n = scandir( SYS_BUS_PCI, & devices, scan_sys_pci_filter, alphasort );
162 p->devices = calloc( n, sizeof( struct pci_device_private ) );
164 if (p->devices != NULL) {
165 for (i = 0 ; i < n ; i++) {
168 unsigned dom, bus, dev, func;
169 struct pci_device_private *device =
170 (struct pci_device_private *) &p->devices[i];
173 sscanf(devices[i]->d_name, "%04x:%02x:%02x.%1u",
174 & dom, & bus, & dev, & func);
176 device->base.domain = dom;
177 device->base.bus = bus;
178 device->base.dev = dev;
179 device->base.func = func;
182 err = pci_device_linux_sysfs_read(& device->base, config, 0,
184 if ((bytes == 48) && !err) {
185 device->base.vendor_id = (uint16_t)config[0]
186 + ((uint16_t)config[1] << 8);
187 device->base.device_id = (uint16_t)config[2]
188 + ((uint16_t)config[3] << 8);
189 device->base.device_class = (uint32_t)config[9]
190 + ((uint32_t)config[10] << 8)
191 + ((uint32_t)config[11] << 16);
192 device->base.revision = config[8];
193 device->base.subvendor_id = (uint16_t)config[44]
194 + ((uint16_t)config[45] << 8);
195 device->base.subdevice_id = (uint16_t)config[46]
196 + ((uint16_t)config[47] << 8);
219 pci_device_linux_sysfs_probe( struct pci_device * dev )
230 err = pci_device_linux_sysfs_read( dev, config, 0, 256, & bytes );
232 struct pci_device_private *priv = (struct pci_device_private *) dev;
234 dev->irq = config[60];
235 priv->header_type = config[14];
238 /* The PCI config registers can be used to obtain information
239 * about the memory and I/O regions for the device. However,
240 * doing so requires some tricky parsing (to correctly handle
241 * 64-bit memory regions) and requires writing to the config
242 * registers. Since we'd like to avoid having to deal with the
243 * parsing issues and non-root users can write to PCI config
244 * registers, we use a different file in the device's sysfs
245 * directory called "resource".
247 * The resource file contains all of the needed information in
248 * a format that is consistent across all platforms. Each BAR
249 * and the expansion ROM have a single line of data containing
250 * 3, 64-bit hex values: the first address in the region,
251 * the last address in the region, and the region's flags.
253 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/resource",
259 fd = open( name, O_RDONLY );
267 bytes = read( fd, resource, 512 );
268 resource[511] = '\0';
273 for ( i = 0 ; i < 6 ; i++ ) {
275 dev->regions[i].base_addr = strtoull( next, & next, 16 );
276 high_addr = strtoull( next, & next, 16 );
277 flags = strtoull( next, & next, 16 );
279 if ( dev->regions[i].base_addr != 0 ) {
280 dev->regions[i].size = (high_addr
281 - dev->regions[i].base_addr) + 1;
283 dev->regions[i].is_IO = (flags & 0x01);
284 dev->regions[i].is_64 = (flags & 0x04);
285 dev->regions[i].is_prefetchable = (flags & 0x08);
289 low_addr = strtoull( next, & next, 16 );
290 high_addr = strtoull( next, & next, 16 );
291 flags = strtoull( next, & next, 16 );
292 if ( low_addr != 0 ) {
293 priv->rom_base = low_addr;
294 dev->rom_size = (high_addr - low_addr) + 1;
304 pci_device_linux_sysfs_read_rom( struct pci_device * dev, void * buffer )
313 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/rom",
320 fd = open( name, O_RDWR );
322 /* If reading the ROM using sysfs fails, fall back to the old
323 * /dev/mem based interface.
325 return pci_device_linux_devmem_read_rom(dev, buffer);
329 if ( fstat( fd, & st ) == -1 ) {
335 /* This is a quirky thing on Linux. Even though the ROM and the file
336 * for the ROM in sysfs are read-only, the string "1" must be written to
337 * the file to enable the ROM. After the data has been read, "0" must be
338 * written to the file to disable the ROM.
341 lseek( fd, 0, SEEK_SET );
343 for ( total_bytes = 0 ; total_bytes < st.st_size ; /* empty */ ) {
344 const int bytes = read( fd, (char *) buffer + total_bytes,
345 st.st_size - total_bytes );
350 else if ( bytes == 0 ) {
354 total_bytes += bytes;
358 lseek( fd, 0, SEEK_SET );
367 pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
368 pciaddr_t offset, pciaddr_t size,
369 pciaddr_t * bytes_read )
372 pciaddr_t temp_size = size;
375 char *data_bytes = data;
377 if ( bytes_read != NULL ) {
381 /* Each device has a directory under sysfs. Within that directory there
382 * is a file named "config". This file used to access the PCI config
383 * space. It is used here to obtain most of the information about the
386 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
393 fd = open( name, O_RDONLY );
399 while ( temp_size > 0 ) {
400 const ssize_t bytes = pread64( fd, data_bytes, temp_size, offset );
402 /* If zero bytes were read, then we assume it's the end of the
415 if ( bytes_read != NULL ) {
416 *bytes_read = size - temp_size;
425 pci_device_linux_sysfs_write( struct pci_device * dev, const void * data,
426 pciaddr_t offset, pciaddr_t size,
427 pciaddr_t * bytes_written )
430 pciaddr_t temp_size = size;
433 const char *data_bytes = data;
435 if ( bytes_written != NULL ) {
439 /* Each device has a directory under sysfs. Within that directory there
440 * is a file named "config". This file used to access the PCI config
441 * space. It is used here to obtain most of the information about the
444 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
451 fd = open( name, O_WRONLY );
457 while ( temp_size > 0 ) {
458 const ssize_t bytes = pwrite64( fd, data_bytes, temp_size, offset );
460 /* If zero bytes were written, then we assume it's the end of the
473 if ( bytes_written != NULL ) {
474 *bytes_written = size - temp_size;
483 * Map a memory region for a device using the Linux sysfs interface.
485 * \param dev Device whose memory region is to be mapped.
486 * \param map Parameters of the mapping that is to be created.
489 * Zero on success or an \c errno value on failure.
491 * \sa pci_device_map_rrange, pci_device_linux_sysfs_unmap_range
494 * Some older 2.6.x kernels don't implement the resourceN files. On those
495 * systems /dev/mem must be used. On these systems it is also possible that
496 * \c mmap64 may need to be used.
499 pci_device_linux_sysfs_map_range(struct pci_device *dev,
500 struct pci_device_mapping *map)
505 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
506 ? (PROT_READ | PROT_WRITE) : PROT_READ;
507 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
509 const off_t offset = map->base - dev->regions[map->region].base_addr;
511 struct mtrr_sentry sentry = {
514 .type = MTRR_TYPE_UNCACHABLE
518 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u",
526 fd = open(name, open_flags);
532 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
533 if (map->memory == MAP_FAILED) {
541 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
542 sentry.type = MTRR_TYPE_WRBACK;
543 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
544 sentry.type = MTRR_TYPE_WRCOMB;
547 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
548 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_ADD_ENTRY, &sentry) < 0) {
549 /* FIXME: Should we report an error in this case?
551 fprintf(stderr, "error setting MTRR "
552 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
553 sentry.base, sentry.size, sentry.type,
554 strerror(errno), errno);
564 * Unmap a memory region for a device using the Linux sysfs interface.
566 * \param dev Device whose memory region is to be unmapped.
567 * \param map Parameters of the mapping that is to be destroyed.
570 * Zero on success or an \c errno value on failure.
572 * \sa pci_device_map_rrange, pci_device_linux_sysfs_map_range
575 * Some older 2.6.x kernels don't implement the resourceN files. On those
576 * systems /dev/mem must be used. On these systems it is also possible that
577 * \c mmap64 may need to be used.
580 pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
581 struct pci_device_mapping *map)
585 struct mtrr_sentry sentry = {
588 .type = MTRR_TYPE_UNCACHABLE
592 err = pci_device_generic_unmap_range (dev, map);
597 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
598 sentry.type = MTRR_TYPE_WRBACK;
599 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
600 sentry.type = MTRR_TYPE_WRCOMB;
603 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
604 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_DEL_ENTRY, &sentry) < 0) {
605 /* FIXME: Should we report an error in this case?
607 fprintf(stderr, "error setting MTRR "
608 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
609 sentry.base, sentry.size, sentry.type,
610 strerror(errno), errno);