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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 * preferred 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 void pci_device_linux_sysfs_enable(struct pci_device *dev);
60 static int pci_device_linux_sysfs_read_rom( struct pci_device * dev,
63 static int pci_device_linux_sysfs_probe( struct pci_device * dev );
65 static int pci_device_linux_sysfs_map_range(struct pci_device *dev,
66 struct pci_device_mapping *map);
68 static int pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
69 struct pci_device_mapping *map);
71 static int pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
72 pciaddr_t offset, pciaddr_t size, pciaddr_t * bytes_read );
74 static int pci_device_linux_sysfs_write( struct pci_device * dev,
75 const void * data, pciaddr_t offset, pciaddr_t size,
76 pciaddr_t * bytes_written );
78 static int pci_device_linux_sysfs_boot_vga( struct pci_device * dev );
80 static const struct pci_system_methods linux_sysfs_methods = {
82 .destroy_device = NULL,
83 .read_rom = pci_device_linux_sysfs_read_rom,
84 .probe = pci_device_linux_sysfs_probe,
85 .map_range = pci_device_linux_sysfs_map_range,
86 .unmap_range = pci_device_linux_sysfs_unmap_range,
88 .read = pci_device_linux_sysfs_read,
89 .write = pci_device_linux_sysfs_write,
91 .fill_capabilities = pci_fill_capabilities_generic,
92 .enable = pci_device_linux_sysfs_enable,
93 .boot_vga = pci_device_linux_sysfs_boot_vga,
96 #define SYS_BUS_PCI "/sys/bus/pci/devices"
99 static int populate_entries(struct pci_system * pci_sys);
103 * Attempt to access PCI subsystem using Linux's sysfs interface.
106 pci_system_linux_sysfs_create( void )
112 /* If the directory "/sys/bus/pci/devices" exists, then the PCI subsystem
113 * can be accessed using this interface.
116 if ( stat( SYS_BUS_PCI, & st ) == 0 ) {
117 pci_sys = calloc( 1, sizeof( struct pci_system ) );
118 if ( pci_sys != NULL ) {
119 pci_sys->methods = & linux_sysfs_methods;
121 pci_sys->mtrr_fd = open("/proc/mtrr", O_WRONLY);
123 err = populate_entries(pci_sys);
138 * Filter out the names "." and ".." from the scanned sysfs entries.
140 * \param d Directory entry being processed by \c scandir.
143 * Zero if the entry name matches either "." or "..", non-zero otherwise.
145 * \sa scandir, populate_entries
148 scan_sys_pci_filter( const struct dirent * d )
150 return !((strcmp( d->d_name, "." ) == 0)
151 || (strcmp( d->d_name, ".." ) == 0));
156 populate_entries( struct pci_system * p )
158 struct dirent ** devices;
164 n = scandir( SYS_BUS_PCI, & devices, scan_sys_pci_filter, alphasort );
167 p->devices = calloc( n, sizeof( struct pci_device_private ) );
169 if (p->devices != NULL) {
170 for (i = 0 ; i < n ; i++) {
173 unsigned dom, bus, dev, func;
174 struct pci_device_private *device =
175 (struct pci_device_private *) &p->devices[i];
178 sscanf(devices[i]->d_name, "%04x:%02x:%02x.%1u",
179 & dom, & bus, & dev, & func);
181 device->base.domain = dom;
182 device->base.bus = bus;
183 device->base.dev = dev;
184 device->base.func = func;
187 err = pci_device_linux_sysfs_read(& device->base, config, 0,
189 if ((bytes == 48) && !err) {
190 device->base.vendor_id = (uint16_t)config[0]
191 + ((uint16_t)config[1] << 8);
192 device->base.device_id = (uint16_t)config[2]
193 + ((uint16_t)config[3] << 8);
194 device->base.device_class = (uint32_t)config[9]
195 + ((uint32_t)config[10] << 8)
196 + ((uint32_t)config[11] << 16);
197 device->base.revision = config[8];
198 device->base.subvendor_id = (uint16_t)config[44]
199 + ((uint16_t)config[45] << 8);
200 device->base.subdevice_id = (uint16_t)config[46]
201 + ((uint16_t)config[47] << 8);
224 pci_device_linux_sysfs_probe( struct pci_device * dev )
235 err = pci_device_linux_sysfs_read( dev, config, 0, 256, & bytes );
237 struct pci_device_private *priv = (struct pci_device_private *) dev;
239 dev->irq = config[60];
240 priv->header_type = config[14];
243 /* The PCI config registers can be used to obtain information
244 * about the memory and I/O regions for the device. However,
245 * doing so requires some tricky parsing (to correctly handle
246 * 64-bit memory regions) and requires writing to the config
247 * registers. Since we'd like to avoid having to deal with the
248 * parsing issues and non-root users can write to PCI config
249 * registers, we use a different file in the device's sysfs
250 * directory called "resource".
252 * The resource file contains all of the needed information in
253 * a format that is consistent across all platforms. Each BAR
254 * and the expansion ROM have a single line of data containing
255 * 3, 64-bit hex values: the first address in the region,
256 * the last address in the region, and the region's flags.
258 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/resource",
264 fd = open( name, O_RDONLY );
272 bytes = read( fd, resource, 512 );
273 resource[511] = '\0';
278 for ( i = 0 ; i < 6 ; i++ ) {
280 dev->regions[i].base_addr = strtoull( next, & next, 16 );
281 high_addr = strtoull( next, & next, 16 );
282 flags = strtoull( next, & next, 16 );
284 if ( dev->regions[i].base_addr != 0 ) {
285 dev->regions[i].size = (high_addr
286 - dev->regions[i].base_addr) + 1;
288 dev->regions[i].is_IO = (flags & 0x01);
289 dev->regions[i].is_64 = (flags & 0x04);
290 dev->regions[i].is_prefetchable = (flags & 0x08);
294 low_addr = strtoull( next, & next, 16 );
295 high_addr = strtoull( next, & next, 16 );
296 flags = strtoull( next, & next, 16 );
297 if ( low_addr != 0 ) {
298 priv->rom_base = low_addr;
299 dev->rom_size = (high_addr - low_addr) + 1;
309 pci_device_linux_sysfs_read_rom( struct pci_device * dev, void * buffer )
319 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/rom",
326 fd = open( name, O_RDWR );
328 /* If reading the ROM using sysfs fails, fall back to the old
329 * /dev/mem based interface.
331 return pci_device_linux_devmem_read_rom(dev, buffer);
335 if ( fstat( fd, & st ) == -1 ) {
340 rom_size = st.st_size;
344 /* This is a quirky thing on Linux. Even though the ROM and the file
345 * for the ROM in sysfs are read-only, the string "1" must be written to
346 * the file to enable the ROM. After the data has been read, "0" must be
347 * written to the file to disable the ROM.
350 lseek( fd, 0, SEEK_SET );
352 for ( total_bytes = 0 ; total_bytes < rom_size ; /* empty */ ) {
353 const int bytes = read( fd, (char *) buffer + total_bytes,
354 rom_size - total_bytes );
359 else if ( bytes == 0 ) {
363 total_bytes += bytes;
367 lseek( fd, 0, SEEK_SET );
376 pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
377 pciaddr_t offset, pciaddr_t size,
378 pciaddr_t * bytes_read )
381 pciaddr_t temp_size = size;
384 char *data_bytes = data;
386 if ( bytes_read != NULL ) {
390 /* Each device has a directory under sysfs. Within that directory there
391 * is a file named "config". This file used to access the PCI config
392 * space. It is used here to obtain most of the information about the
395 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
402 fd = open( name, O_RDONLY );
408 while ( temp_size > 0 ) {
409 const ssize_t bytes = pread64( fd, data_bytes, temp_size, offset );
411 /* If zero bytes were read, then we assume it's the end of the
424 if ( bytes_read != NULL ) {
425 *bytes_read = size - temp_size;
434 pci_device_linux_sysfs_write( struct pci_device * dev, const void * data,
435 pciaddr_t offset, pciaddr_t size,
436 pciaddr_t * bytes_written )
439 pciaddr_t temp_size = size;
442 const char *data_bytes = data;
444 if ( bytes_written != NULL ) {
448 /* Each device has a directory under sysfs. Within that directory there
449 * is a file named "config". This file used to access the PCI config
450 * space. It is used here to obtain most of the information about the
453 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
460 fd = open( name, O_WRONLY );
466 while ( temp_size > 0 ) {
467 const ssize_t bytes = pwrite64( fd, data_bytes, temp_size, offset );
469 /* If zero bytes were written, then we assume it's the end of the
482 if ( bytes_written != NULL ) {
483 *bytes_written = size - temp_size;
491 pci_device_linux_sysfs_map_range_wc(struct pci_device *dev,
492 struct pci_device_mapping *map)
496 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
497 ? (PROT_READ | PROT_WRITE) : PROT_READ;
498 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
500 const off_t offset = map->base - dev->regions[map->region].base_addr;
502 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u_wc",
509 fd = open(name, open_flags);
513 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
514 if (map->memory == MAP_FAILED) {
526 * Map a memory region for a device using the Linux sysfs interface.
528 * \param dev Device whose memory region is to be mapped.
529 * \param map Parameters of the mapping that is to be created.
532 * Zero on success or an \c errno value on failure.
534 * \sa pci_device_map_rrange, pci_device_linux_sysfs_unmap_range
537 * Some older 2.6.x kernels don't implement the resourceN files. On those
538 * systems /dev/mem must be used. On these systems it is also possible that
539 * \c mmap64 may need to be used.
542 pci_device_linux_sysfs_map_range(struct pci_device *dev,
543 struct pci_device_mapping *map)
548 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
549 ? (PROT_READ | PROT_WRITE) : PROT_READ;
550 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
552 const off_t offset = map->base - dev->regions[map->region].base_addr;
554 struct mtrr_sentry sentry = {
557 .type = MTRR_TYPE_UNCACHABLE
561 /* For WC mappings, try sysfs resourceN_wc file first */
562 if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) &&
563 !pci_device_linux_sysfs_map_range_wc(dev, map))
566 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u",
574 fd = open(name, open_flags);
580 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
581 if (map->memory == MAP_FAILED) {
588 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
589 sentry.type = MTRR_TYPE_WRBACK;
590 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
591 sentry.type = MTRR_TYPE_WRCOMB;
594 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
595 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_ADD_ENTRY, &sentry) < 0) {
596 /* FIXME: Should we report an error in this case?
598 fprintf(stderr, "error setting MTRR "
599 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
600 sentry.base, sentry.size, sentry.type,
601 strerror(errno), errno);
604 /* KLUDGE ALERT -- rewrite the PTEs to turn off the CD and WT bits */
605 mprotect (map->memory, map->size, PROT_NONE);
606 err = mprotect (map->memory, map->size, PROT_READ|PROT_WRITE);
609 fprintf(stderr, "mprotect(PROT_READ | PROT_WRITE) failed: %s\n",
611 fprintf(stderr, "remapping without mprotect performance kludge.\n");
613 munmap(map->memory, map->size);
614 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
615 if (map->memory == MAP_FAILED) {
630 * Unmap a memory region for a device using the Linux sysfs interface.
632 * \param dev Device whose memory region is to be unmapped.
633 * \param map Parameters of the mapping that is to be destroyed.
636 * Zero on success or an \c errno value on failure.
638 * \sa pci_device_map_rrange, pci_device_linux_sysfs_map_range
641 * Some older 2.6.x kernels don't implement the resourceN files. On those
642 * systems /dev/mem must be used. On these systems it is also possible that
643 * \c mmap64 may need to be used.
646 pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
647 struct pci_device_mapping *map)
651 struct mtrr_sentry sentry = {
654 .type = MTRR_TYPE_UNCACHABLE
658 err = pci_device_generic_unmap_range (dev, map);
663 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
664 sentry.type = MTRR_TYPE_WRBACK;
665 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
666 sentry.type = MTRR_TYPE_WRCOMB;
669 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
670 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_DEL_ENTRY, &sentry) < 0) {
671 /* FIXME: Should we report an error in this case?
673 fprintf(stderr, "error setting MTRR "
674 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
675 sentry.base, sentry.size, sentry.type,
676 strerror(errno), errno);
685 static void pci_device_linux_sysfs_enable(struct pci_device *dev)
690 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/enable",
697 fd = open( name, O_RDWR );
705 static int pci_device_linux_sysfs_boot_vga(struct pci_device *dev)
712 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/boot_vga",
719 fd = open( name, O_RDWR );
723 bytes_read = read(fd, reply, 1);