2 * (C) Copyright IBM Corporation 2006
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * on the rights to use, copy, modify, merge, publish, distribute, sub
9 * license, and/or sell copies of the Software, and to permit persons to whom
10 * the Software is furnished to do so, subject to the following conditions:
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
19 * IBM AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
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 );
79 static int pci_device_linux_sysfs_has_kernel_driver(struct pci_device *dev);
81 static const struct pci_system_methods linux_sysfs_methods = {
83 .destroy_device = NULL,
84 .read_rom = pci_device_linux_sysfs_read_rom,
85 .probe = pci_device_linux_sysfs_probe,
86 .map_range = pci_device_linux_sysfs_map_range,
87 .unmap_range = pci_device_linux_sysfs_unmap_range,
89 .read = pci_device_linux_sysfs_read,
90 .write = pci_device_linux_sysfs_write,
92 .fill_capabilities = pci_fill_capabilities_generic,
93 .enable = pci_device_linux_sysfs_enable,
94 .boot_vga = pci_device_linux_sysfs_boot_vga,
95 .has_kernel_driver = pci_device_linux_sysfs_has_kernel_driver,
98 #define SYS_BUS_PCI "/sys/bus/pci/devices"
101 static int populate_entries(struct pci_system * pci_sys);
105 * Attempt to access PCI subsystem using Linux's sysfs interface.
108 pci_system_linux_sysfs_create( void )
114 /* If the directory "/sys/bus/pci/devices" exists, then the PCI subsystem
115 * can be accessed using this interface.
118 if ( stat( SYS_BUS_PCI, & st ) == 0 ) {
119 pci_sys = calloc( 1, sizeof( struct pci_system ) );
120 if ( pci_sys != NULL ) {
121 pci_sys->methods = & linux_sysfs_methods;
123 pci_sys->mtrr_fd = open("/proc/mtrr", O_WRONLY);
125 err = populate_entries(pci_sys);
140 * Filter out the names "." and ".." from the scanned sysfs entries.
142 * \param d Directory entry being processed by \c scandir.
145 * Zero if the entry name matches either "." or "..", non-zero otherwise.
147 * \sa scandir, populate_entries
150 scan_sys_pci_filter( const struct dirent * d )
152 return !((strcmp( d->d_name, "." ) == 0)
153 || (strcmp( d->d_name, ".." ) == 0));
158 populate_entries( struct pci_system * p )
160 struct dirent ** devices;
166 n = scandir( SYS_BUS_PCI, & devices, scan_sys_pci_filter, alphasort );
169 p->devices = calloc( n, sizeof( struct pci_device_private ) );
171 if (p->devices != NULL) {
172 for (i = 0 ; i < n ; i++) {
175 unsigned dom, bus, dev, func;
176 struct pci_device_private *device =
177 (struct pci_device_private *) &p->devices[i];
180 sscanf(devices[i]->d_name, "%04x:%02x:%02x.%1u",
181 & dom, & bus, & dev, & func);
183 device->base.domain = dom;
184 device->base.bus = bus;
185 device->base.dev = dev;
186 device->base.func = func;
189 err = pci_device_linux_sysfs_read(& device->base, config, 0,
191 if ((bytes == 48) && !err) {
192 device->base.vendor_id = (uint16_t)config[0]
193 + ((uint16_t)config[1] << 8);
194 device->base.device_id = (uint16_t)config[2]
195 + ((uint16_t)config[3] << 8);
196 device->base.device_class = (uint32_t)config[9]
197 + ((uint32_t)config[10] << 8)
198 + ((uint32_t)config[11] << 16);
199 device->base.revision = config[8];
200 device->base.subvendor_id = (uint16_t)config[44]
201 + ((uint16_t)config[45] << 8);
202 device->base.subdevice_id = (uint16_t)config[46]
203 + ((uint16_t)config[47] << 8);
226 pci_device_linux_sysfs_probe( struct pci_device * dev )
237 err = pci_device_linux_sysfs_read( dev, config, 0, 256, & bytes );
239 struct pci_device_private *priv = (struct pci_device_private *) dev;
241 dev->irq = config[60];
242 priv->header_type = config[14];
245 /* The PCI config registers can be used to obtain information
246 * about the memory and I/O regions for the device. However,
247 * doing so requires some tricky parsing (to correctly handle
248 * 64-bit memory regions) and requires writing to the config
249 * registers. Since we'd like to avoid having to deal with the
250 * parsing issues and non-root users can write to PCI config
251 * registers, we use a different file in the device's sysfs
252 * directory called "resource".
254 * The resource file contains all of the needed information in
255 * a format that is consistent across all platforms. Each BAR
256 * and the expansion ROM have a single line of data containing
257 * 3, 64-bit hex values: the first address in the region,
258 * the last address in the region, and the region's flags.
260 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/resource",
266 fd = open( name, O_RDONLY );
274 bytes = read( fd, resource, 512 );
275 resource[511] = '\0';
280 for ( i = 0 ; i < 6 ; i++ ) {
282 dev->regions[i].base_addr = strtoull( next, & next, 16 );
283 high_addr = strtoull( next, & next, 16 );
284 flags = strtoull( next, & next, 16 );
286 if ( dev->regions[i].base_addr != 0 ) {
287 dev->regions[i].size = (high_addr
288 - dev->regions[i].base_addr) + 1;
290 dev->regions[i].is_IO = (flags & 0x01);
291 dev->regions[i].is_64 = (flags & 0x04);
292 dev->regions[i].is_prefetchable = (flags & 0x08);
296 low_addr = strtoull( next, & next, 16 );
297 high_addr = strtoull( next, & next, 16 );
298 flags = strtoull( next, & next, 16 );
299 if ( low_addr != 0 ) {
300 priv->rom_base = low_addr;
301 dev->rom_size = (high_addr - low_addr) + 1;
311 pci_device_linux_sysfs_read_rom( struct pci_device * dev, void * buffer )
321 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/rom",
328 fd = open( name, O_RDWR );
330 /* If reading the ROM using sysfs fails, fall back to the old
331 * /dev/mem based interface.
333 return pci_device_linux_devmem_read_rom(dev, buffer);
337 if ( fstat( fd, & st ) == -1 ) {
342 rom_size = st.st_size;
346 /* This is a quirky thing on Linux. Even though the ROM and the file
347 * for the ROM in sysfs are read-only, the string "1" must be written to
348 * the file to enable the ROM. After the data has been read, "0" must be
349 * written to the file to disable the ROM.
352 lseek( fd, 0, SEEK_SET );
354 for ( total_bytes = 0 ; total_bytes < rom_size ; /* empty */ ) {
355 const int bytes = read( fd, (char *) buffer + total_bytes,
356 rom_size - total_bytes );
361 else if ( bytes == 0 ) {
365 total_bytes += bytes;
369 lseek( fd, 0, SEEK_SET );
378 pci_device_linux_sysfs_read( struct pci_device * dev, void * data,
379 pciaddr_t offset, pciaddr_t size,
380 pciaddr_t * bytes_read )
383 pciaddr_t temp_size = size;
386 char *data_bytes = data;
388 if ( bytes_read != NULL ) {
392 /* Each device has a directory under sysfs. Within that directory there
393 * is a file named "config". This file used to access the PCI config
394 * space. It is used here to obtain most of the information about the
397 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
404 fd = open( name, O_RDONLY );
410 while ( temp_size > 0 ) {
411 const ssize_t bytes = pread64( fd, data_bytes, temp_size, offset );
413 /* If zero bytes were read, then we assume it's the end of the
426 if ( bytes_read != NULL ) {
427 *bytes_read = size - temp_size;
436 pci_device_linux_sysfs_write( struct pci_device * dev, const void * data,
437 pciaddr_t offset, pciaddr_t size,
438 pciaddr_t * bytes_written )
441 pciaddr_t temp_size = size;
444 const char *data_bytes = data;
446 if ( bytes_written != NULL ) {
450 /* Each device has a directory under sysfs. Within that directory there
451 * is a file named "config". This file used to access the PCI config
452 * space. It is used here to obtain most of the information about the
455 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/config",
462 fd = open( name, O_WRONLY );
468 while ( temp_size > 0 ) {
469 const ssize_t bytes = pwrite64( fd, data_bytes, temp_size, offset );
471 /* If zero bytes were written, then we assume it's the end of the
484 if ( bytes_written != NULL ) {
485 *bytes_written = size - temp_size;
493 pci_device_linux_sysfs_map_range_wc(struct pci_device *dev,
494 struct pci_device_mapping *map)
498 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
499 ? (PROT_READ | PROT_WRITE) : PROT_READ;
500 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
502 const off_t offset = map->base - dev->regions[map->region].base_addr;
504 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u_wc",
511 fd = open(name, open_flags);
515 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
516 if (map->memory == MAP_FAILED) {
528 * Map a memory region for a device using the Linux sysfs interface.
530 * \param dev Device whose memory region is to be mapped.
531 * \param map Parameters of the mapping that is to be created.
534 * Zero on success or an \c errno value on failure.
536 * \sa pci_device_map_rrange, pci_device_linux_sysfs_unmap_range
539 * Some older 2.6.x kernels don't implement the resourceN files. On those
540 * systems /dev/mem must be used. On these systems it is also possible that
541 * \c mmap64 may need to be used.
544 pci_device_linux_sysfs_map_range(struct pci_device *dev,
545 struct pci_device_mapping *map)
550 const int prot = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
551 ? (PROT_READ | PROT_WRITE) : PROT_READ;
552 const int open_flags = ((map->flags & PCI_DEV_MAP_FLAG_WRITABLE) != 0)
554 const off_t offset = map->base - dev->regions[map->region].base_addr;
556 struct mtrr_sentry sentry = {
559 .type = MTRR_TYPE_UNCACHABLE
563 /* For WC mappings, try sysfs resourceN_wc file first */
564 if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) &&
565 !pci_device_linux_sysfs_map_range_wc(dev, map))
568 snprintf(name, 255, "%s/%04x:%02x:%02x.%1u/resource%u",
576 fd = open(name, open_flags);
582 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
583 if (map->memory == MAP_FAILED) {
590 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
591 sentry.type = MTRR_TYPE_WRBACK;
592 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
593 sentry.type = MTRR_TYPE_WRCOMB;
596 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
597 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_ADD_ENTRY, &sentry) < 0) {
598 /* FIXME: Should we report an error in this case?
600 fprintf(stderr, "error setting MTRR "
601 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
602 sentry.base, sentry.size, sentry.type,
603 strerror(errno), errno);
606 /* KLUDGE ALERT -- rewrite the PTEs to turn off the CD and WT bits */
607 mprotect (map->memory, map->size, PROT_NONE);
608 err = mprotect (map->memory, map->size, PROT_READ|PROT_WRITE);
611 fprintf(stderr, "mprotect(PROT_READ | PROT_WRITE) failed: %s\n",
613 fprintf(stderr, "remapping without mprotect performance kludge.\n");
615 munmap(map->memory, map->size);
616 map->memory = mmap(NULL, map->size, prot, MAP_SHARED, fd, offset);
617 if (map->memory == MAP_FAILED) {
632 * Unmap a memory region for a device using the Linux sysfs interface.
634 * \param dev Device whose memory region is to be unmapped.
635 * \param map Parameters of the mapping that is to be destroyed.
638 * Zero on success or an \c errno value on failure.
640 * \sa pci_device_map_rrange, pci_device_linux_sysfs_map_range
643 * Some older 2.6.x kernels don't implement the resourceN files. On those
644 * systems /dev/mem must be used. On these systems it is also possible that
645 * \c mmap64 may need to be used.
648 pci_device_linux_sysfs_unmap_range(struct pci_device *dev,
649 struct pci_device_mapping *map)
653 struct mtrr_sentry sentry = {
656 .type = MTRR_TYPE_UNCACHABLE
660 err = pci_device_generic_unmap_range (dev, map);
665 if ((map->flags & PCI_DEV_MAP_FLAG_CACHABLE) != 0) {
666 sentry.type = MTRR_TYPE_WRBACK;
667 } else if ((map->flags & PCI_DEV_MAP_FLAG_WRITE_COMBINE) != 0) {
668 sentry.type = MTRR_TYPE_WRCOMB;
671 if (pci_sys->mtrr_fd != -1 && sentry.type != MTRR_TYPE_UNCACHABLE) {
672 if (ioctl(pci_sys->mtrr_fd, MTRRIOC_DEL_ENTRY, &sentry) < 0) {
673 /* FIXME: Should we report an error in this case?
675 fprintf(stderr, "error setting MTRR "
676 "(base = 0x%08lx, size = 0x%08x, type = %u) %s (%d)\n",
677 sentry.base, sentry.size, sentry.type,
678 strerror(errno), errno);
687 static void pci_device_linux_sysfs_enable(struct pci_device *dev)
692 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/enable",
699 fd = open( name, O_RDWR );
707 static int pci_device_linux_sysfs_boot_vga(struct pci_device *dev)
714 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/boot_vga",
721 fd = open( name, O_RDONLY );
725 bytes_read = read(fd, reply, 1);
735 static int pci_device_linux_sysfs_has_kernel_driver(struct pci_device *dev)
741 snprintf( name, 255, "%s/%04x:%02x:%02x.%1u/driver",
748 ret = stat(name, &dummy);