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28 * Access PCI subsystem using Linux's sysfs interface. This interface is
29 * available starting somewhere in the late 2.5.x kernel phase, and is the
30 * preferred method on all 2.6.x kernels.
32 * \author Ian Romanick <idr@us.ibm.com>
41 #include <sys/types.h>
48 #if defined(__i386__) || defined(__x86_64__) || defined(__arm__)
54 #define outb(x) do {} while (0)
55 #define outw(x) do {} while (0)
56 #define outl(x) do {} while (0)
64 #include <sys/ioctl.h>
67 #include "pciaccess.h"
68 #include "pciaccess_private.h"
69 #include "linux_devmem.h"
71 static const struct pci_system_methods linux_sysfs_methods;
73 #define SYS_BUS_PCI "/sys/bus/pci/devices"
76 pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
77 pciaddr_t offset, pciaddr_t size,
78 pciaddr_t * bytes_read );
80 static int populate_entries(struct pci_system * pci_sys);
83 * Attempt to access PCI subsystem using Linux's sysfs interface.
86 pci_system_linux_sysfs_create( void )
92 /* If the directory "/sys/bus/pci/devices" exists, then the PCI subsystem
93 * can be accessed using this interface.
96 if ( stat( SYS_BUS_PCI, & st ) == 0 ) {
97 pci_sys = calloc( 1, sizeof( struct pci_system ) );
98 if ( pci_sys != NULL ) {
99 pci_sys->methods = & linux_sysfs_methods;
101 pci_sys->mtrr_fd = open("/proc/mtrr", O_WRONLY | O_CLOEXEC);
103 err = populate_entries(pci_sys);
118 * Filter out the names "." and ".." from the scanned sysfs entries.
120 * \param d Directory entry being processed by \c scandir.
123 * Zero if the entry name matches either "." or "..", non-zero otherwise.
125 * \sa scandir, populate_entries
128 scan_sys_pci_filter( const struct dirent * d )
130 return !((strcmp( d->d_name, "." ) == 0)
131 || (strcmp( d->d_name, ".." ) == 0));
136 populate_entries( struct pci_system * p )
138 struct dirent ** devices = NULL;
144 n = scandir( SYS_BUS_PCI, & devices, scan_sys_pci_filter, alphasort );
147 p->devices = calloc( n, sizeof( struct pci_device_private ) );
149 if (p->devices != NULL) {
150 for (i = 0 ; i < n ; i++) {
153 unsigned dom, bus, dev, func;
154 struct pci_device_private *device =
155 (struct pci_device_private *) &p->devices[i];
158 sscanf(devices[i]->d_name, "%04x:%02x:%02x.%1u",
159 & dom, & bus, & dev, & func);
161 device->base.domain = dom;
162 device->base.bus = bus;
163 device->base.dev = dev;
164 device->base.func = func;
167 err = pci_device_linux_sysfs_read(& device->base, config, 0,
169 if ((bytes == 48) && !err) {
170 device->base.vendor_id = (uint16_t)config[0]
171 + ((uint16_t)config[1] << 8);
172 device->base.device_id = (uint16_t)config[2]
173 + ((uint16_t)config[3] << 8);
174 device->base.device_class = (uint32_t)config[9]
175 + ((uint32_t)config[10] << 8)
176 + ((uint32_t)config[11] << 16);
177 device->base.revision = config[8];
178 device->base.subvendor_id = (uint16_t)config[44]
179 + ((uint16_t)config[45] << 8);
180 device->base.subdevice_id = (uint16_t)config[46]
181 + ((uint16_t)config[47] << 8);
194 for (i = 0; i < n; i++)
208 pci_device_linux_sysfs_probe( struct pci_device * dev )
219 err = pci_device_linux_sysfs_read( dev, config, 0, 256, & bytes );
221 struct pci_device_private *priv = (struct pci_device_private *) dev;
223 dev->irq = config[60];
224 priv->header_type = config[14];
227 /* The PCI config registers can be used to obtain information
228 * about the memory and I/O regions for the device. However,
229 * doing so requires some tricky parsing (to correctly handle
230 * 64-bit memory regions) and requires writing to the config
231 * registers. Since we'd like to avoid having to deal with the
232 * parsing issues and non-root users can write to PCI config
233 * registers, we use a different file in the device's sysfs
234 * directory called "resource".
236 * The resource file contains all of the needed information in
237 * a format that is consistent across all platforms. Each BAR
238 * and the expansion ROM have a single line of data containing
239 * 3, 64-bit hex values: the first address in the region,
240 * the last address in the region, and the region's flags.
242 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/resource",
248 fd = open( name, O_RDONLY | O_CLOEXEC);
256 bytes = read( fd, resource, 512 );
257 resource[511] = '\0';
262 for ( i = 0 ; i < 6 ; i++ ) {
264 dev->regions[i].base_addr = strtoull( next, & next, 16 );
265 high_addr = strtoull( next, & next, 16 );
266 flags = strtoull( next, & next, 16 );
268 if ( dev->regions[i].base_addr != 0 ) {
269 dev->regions[i].size = (high_addr
270 - dev->regions[i].base_addr) + 1;
272 dev->regions[i].is_IO = (flags & 0x01);
273 dev->regions[i].is_64 = (flags & 0x04);
274 dev->regions[i].is_prefetchable = (flags & 0x08);
278 low_addr = strtoull( next, & next, 16 );
279 high_addr = strtoull( next, & next, 16 );
280 flags = strtoull( next, & next, 16 );
281 if ( low_addr != 0 ) {
282 priv->rom_base = low_addr;
283 dev->rom_size = (high_addr - low_addr) + 1;
293 pci_device_linux_sysfs_read_rom( struct pci_device * dev, void * buffer )
303 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/rom",
310 fd = open( name, O_RDWR | O_CLOEXEC);
313 /* If reading the ROM using sysfs fails, fall back to the old
314 * /dev/mem based interface.
315 * disable this for newer kernels using configure
317 return pci_device_linux_devmem_read_rom(dev, buffer);
324 if ( fstat( fd, & st ) == -1 ) {
329 rom_size = st.st_size;
333 /* This is a quirky thing on Linux. Even though the ROM and the file
334 * for the ROM in sysfs are read-only, the string "1" must be written to
335 * the file to enable the ROM. After the data has been read, "0" must be
336 * written to the file to disable the ROM.
339 lseek( fd, 0, SEEK_SET );
341 for ( total_bytes = 0 ; total_bytes < rom_size ; /* empty */ ) {
342 const int bytes = read( fd, (char *) buffer + total_bytes,
343 rom_size - total_bytes );
348 else if ( bytes == 0 ) {
352 total_bytes += bytes;
356 lseek( fd, 0, SEEK_SET );
365 pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
366 pciaddr_t offset, pciaddr_t size,
367 pciaddr_t * bytes_read )
370 pciaddr_t temp_size = size;
373 char *data_bytes = data;
375 if ( bytes_read != NULL ) {
379 /* Each device has a directory under sysfs. Within that directory there
380 * is a file named "config". This file used to access the PCI config
381 * space. It is used here to obtain most of the information about the
384 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
391 fd = open( name, O_RDONLY | O_CLOEXEC);
397 while ( temp_size > 0 ) {
398 const ssize_t bytes = pread64( fd, data_bytes, temp_size, offset );
400 /* 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 | O_CLOEXEC);
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
475 if ( bytes_written != NULL ) {
476 *bytes_written = size - temp_size;
484 pci_device_linux_sysfs_map_range_wc(struct pci_device *dev,
485 struct pci_device_mapping *map)
489 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
490 ? (PROT_READ | PROT_WRITE) : PROT_READ;
491 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
493 const off_t offset = map->base - dev->regions[map->region].base_addr;
495 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u_wc",
502 fd = open(name, open_flags | O_CLOEXEC);
506 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
507 if (map->memory == MAP_FAILED) {
519 * Map a memory region for a device using the Linux sysfs interface.
521 * \param dev Device whose memory region is to be mapped.
522 * \param map Parameters of the mapping that is to be created.
525 * Zero on success or an \c errno value on failure.
527 * \sa pci_device_map_rrange, pci_device_linux_sysfs_unmap_range
530 * Some older 2.6.x kernels don't implement the resourceN files. On those
531 * systems /dev/mem must be used. On these systems it is also possible that
532 * \c mmap64 may need to be used.
535 pci_device_linux_sysfs_map_range(struct pci_device *dev,
536 struct pci_device_mapping *map)
541 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
542 ? (PROT_READ | PROT_WRITE) : PROT_READ;
543 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
545 const off_t offset = map->base - dev->regions[map->region].base_addr;
547 struct mtrr_sentry sentry = {
550 .type = MTRR_TYPE_UNCACHABLE
554 /* For WC mappings, try sysfs resourceN_wc file first */
555 if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) &&
556 !pci_device_linux_sysfs_map_range_wc(dev, map))
559 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u",
567 fd = open(name, open_flags | O_CLOEXEC);
573 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
574 if (map->memory == MAP_FAILED) {
581 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
582 sentry.type = MTRR_TYPE_WRBACK;
583 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
584 sentry.type = MTRR_TYPE_WRCOMB;
587 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
588 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_ADD_ENTRY, &sentry) < 0) {
589 /* FIXME: Should we report an error in this case?
591 fprintf(stderr, "error setting MTRR "
592 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
593 sentry.base, sentry.size, sentry.type,
594 strerror(errno), errno);
597 /* KLUDGE ALERT -- rewrite the PTEs to turn off the CD and WT bits */
598 mprotect (map->memory, map->size, PROT_NONE);
599 err = mprotect (map->memory, map->size, PROT_READ|PROT_WRITE);
602 fprintf(stderr, "mprotect(PROT_READ | PROT_WRITE) failed: %s\n",
604 fprintf(stderr, "remapping without mprotect performance kludge.\n");
606 munmap(map->memory, map->size);
607 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
608 if (map->memory == MAP_FAILED) {
623 * Unmap a memory region for a device using the Linux sysfs interface.
625 * \param dev Device whose memory region is to be unmapped.
626 * \param map Parameters of the mapping that is to be destroyed.
629 * Zero on success or an \c errno value on failure.
631 * \sa pci_device_map_rrange, pci_device_linux_sysfs_map_range
634 * Some older 2.6.x kernels don't implement the resourceN files. On those
635 * systems /dev/mem must be used. On these systems it is also possible that
636 * \c mmap64 may need to be used.
639 pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
640 struct pci_device_mapping *map)
644 struct mtrr_sentry sentry = {
647 .type = MTRR_TYPE_UNCACHABLE
651 err = pci_device_generic_unmap_range (dev, map);
656 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
657 sentry.type = MTRR_TYPE_WRBACK;
658 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
659 sentry.type = MTRR_TYPE_WRCOMB;
662 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
663 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_DEL_ENTRY, &sentry) < 0) {
664 /* FIXME: Should we report an error in this case?
666 fprintf(stderr, "error setting MTRR "
667 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
668 sentry.base, sentry.size, sentry.type,
669 strerror(errno), errno);
678 static void pci_device_linux_sysfs_enable(struct pci_device *dev)
683 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/enable",
690 fd = open( name, O_RDWR | O_CLOEXEC);
698 static int pci_device_linux_sysfs_boot_vga(struct pci_device *dev)
705 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/boot_vga",
712 fd = open( name, O_RDONLY | O_CLOEXEC);
716 bytes_read = read(fd, reply, 1);
726 static int pci_device_linux_sysfs_has_kernel_driver(struct pci_device *dev)
732 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/driver",
739 ret = stat(name, &dummy);
745 static struct pci_io_handle *
746 pci_device_linux_sysfs_open_device_io(struct pci_io_handle *ret,
747 struct pci_device *dev, int bar,
748 pciaddr_t base, pciaddr_t size)
752 snprintf(name, PATH_MAX, "%s/%04x:%02x:%02x.%1u/resource%d",
753 SYS_BUS_PCI, dev->domain, dev->bus, dev->dev, dev->func, bar);
755 ret->fd = open(name, O_RDWR | O_CLOEXEC);
766 static struct pci_io_handle *
767 pci_device_linux_sysfs_open_legacy_io(struct pci_io_handle *ret,
768 struct pci_device *dev, pciaddr_t base,
773 /* First check if there's a legacy io method for the device */
775 snprintf(name, PATH_MAX, "/sys/class/pci_bus/%04x:%02x/legacy_io",
776 dev->domain, dev->bus);
778 ret->fd = open(name, O_RDWR | O_CLOEXEC);
782 dev = pci_device_get_parent_bridge(dev);
786 * You would think you'd want to use /dev/port here. Don't make that
787 * mistake, /dev/port only does byte-wide i/o cycles which means it
788 * doesn't work. If you think this is stupid, well, you're right.
791 /* If we've no other choice, iopl */
804 pci_device_linux_sysfs_close_io(struct pci_device *dev,
805 struct pci_io_handle *handle)
812 pci_device_linux_sysfs_read32(struct pci_io_handle *handle, uint32_t port)
817 pread(handle->fd, &ret, 4, port + handle->base);
819 ret = inl(port + handle->base);
825 pci_device_linux_sysfs_read16(struct pci_io_handle *handle, uint32_t port)
830 pread(handle->fd, &ret, 2, port + handle->base);
832 ret = inw(port + handle->base);
838 pci_device_linux_sysfs_read8(struct pci_io_handle *handle, uint32_t port)
843 pread(handle->fd, &ret, 1, port + handle->base);
845 ret = inb(port + handle->base);
851 pci_device_linux_sysfs_write32(struct pci_io_handle *handle, uint32_t port,
855 pwrite(handle->fd, &data, 4, port + handle->base);
857 outl(data, port + handle->base);
861 pci_device_linux_sysfs_write16(struct pci_io_handle *handle, uint32_t port,
865 pwrite(handle->fd, &data, 2, port + handle->base);
867 outw(data, port + handle->base);
871 pci_device_linux_sysfs_write8(struct pci_io_handle *handle, uint32_t port,
875 pwrite(handle->fd, &data, 1, port + handle->base);
877 outb(data, port + handle->base);
881 pci_device_linux_sysfs_map_legacy(struct pci_device *dev, pciaddr_t base,
882 pciaddr_t size, unsigned map_flags, void **addr)
885 int flags = O_RDONLY;
886 int prot = PROT_READ;
890 if (map_flags & PCI_DEV_MAP_FLAG_WRITABLE) {
891 flags = O_RDWR; /* O_RDWR != O_WRONLY | O_RDONLY */;
895 /* First check if there's a legacy memory method for the device */
897 snprintf(name, PATH_MAX, "/sys/class/pci_bus/%04x:%02x/legacy_mem",
898 dev->domain, dev->bus);
900 fd = open(name, flags | O_CLOEXEC);
904 dev = pci_device_get_parent_bridge(dev);
907 /* If not, /dev/mem is the best we can do */
909 fd = open("/dev/mem", flags | O_CLOEXEC);
914 *addr = mmap(NULL, size, prot, MAP_SHARED, fd, base);
915 if (*addr == MAP_FAILED) {
924 pci_device_linux_sysfs_unmap_legacy(struct pci_device *dev, void *addr, pciaddr_t size)
926 return munmap(addr, size);
931 pci_system_linux_destroy(void)
934 if (pci_sys->mtrr_fd != -1)
935 close(pci_sys->mtrr_fd);
939 static const struct pci_system_methods linux_sysfs_methods = {
940 .destroy = pci_system_linux_destroy,
941 .destroy_device = NULL,
942 .read_rom = pci_device_linux_sysfs_read_rom,
943 .probe = pci_device_linux_sysfs_probe,
944 .map_range = pci_device_linux_sysfs_map_range,
945 .unmap_range = pci_device_linux_sysfs_unmap_range,
947 .read = pci_device_linux_sysfs_read,
948 .write = pci_device_linux_sysfs_write,
950 .fill_capabilities = pci_fill_capabilities_generic,
951 .enable = pci_device_linux_sysfs_enable,
952 .boot_vga = pci_device_linux_sysfs_boot_vga,
953 .has_kernel_driver = pci_device_linux_sysfs_has_kernel_driver,
955 .open_device_io = pci_device_linux_sysfs_open_device_io,
956 .open_legacy_io = pci_device_linux_sysfs_open_legacy_io,
957 .close_io = pci_device_linux_sysfs_close_io,
958 .read32 = pci_device_linux_sysfs_read32,
959 .read16 = pci_device_linux_sysfs_read16,
960 .read8 = pci_device_linux_sysfs_read8,
961 .write32 = pci_device_linux_sysfs_write32,
962 .write16 = pci_device_linux_sysfs_write16,
963 .write8 = pci_device_linux_sysfs_write8,
965 .map_legacy = pci_device_linux_sysfs_map_legacy,
966 .unmap_legacy = pci_device_linux_sysfs_unmap_legacy,