1 /* 2 * drivers/firmware/qemu_fw_cfg.c 3 * 4 * Copyright 2015 Carnegie Mellon University 5 * 6 * Expose entries from QEMU's firmware configuration (fw_cfg) device in 7 * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/..."). 8 * 9 * The fw_cfg device may be instantiated via either an ACPI node (on x86 10 * and select subsets of aarch64), a Device Tree node (on arm), or using 11 * a kernel module (or command line) parameter with the following syntax: 12 * 13 * [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]] 14 * or 15 * [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]] 16 * 17 * where: 18 * <size> := size of ioport or mmio range 19 * <base> := physical base address of ioport or mmio range 20 * <ctrl_off> := (optional) offset of control register 21 * <data_off> := (optional) offset of data register 22 * <dma_off> := (optional) offset of dma register 23 * 24 * e.g.: 25 * qemu_fw_cfg.ioport=12@0x510:0:1:4 (the default on x86) 26 * or 27 * qemu_fw_cfg.mmio=16@0x9020000:8:0:16 (the default on arm) 28 */ 29 30 #include <linux/module.h> 31 #include <linux/mod_devicetable.h> 32 #include <linux/platform_device.h> 33 #include <linux/acpi.h> 34 #include <linux/slab.h> 35 #include <linux/io.h> 36 #include <linux/ioport.h> 37 #include <uapi/linux/qemu_fw_cfg.h> 38 #include <linux/delay.h> 39 #include <linux/crash_dump.h> 40 #include <linux/crash_core.h> 41 42 MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>"); 43 MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); 44 MODULE_LICENSE("GPL"); 45 46 /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ 47 static u32 fw_cfg_rev; 48 49 /* fw_cfg device i/o register addresses */ 50 static bool fw_cfg_is_mmio; 51 static phys_addr_t fw_cfg_p_base; 52 static resource_size_t fw_cfg_p_size; 53 static void __iomem *fw_cfg_dev_base; 54 static void __iomem *fw_cfg_reg_ctrl; 55 static void __iomem *fw_cfg_reg_data; 56 static void __iomem *fw_cfg_reg_dma; 57 58 /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */ 59 static DEFINE_MUTEX(fw_cfg_dev_lock); 60 61 /* pick appropriate endianness for selector key */ 62 static void fw_cfg_sel_endianness(u16 key) 63 { 64 if (fw_cfg_is_mmio) 65 iowrite16be(key, fw_cfg_reg_ctrl); 66 else 67 iowrite16(key, fw_cfg_reg_ctrl); 68 } 69 70 #ifdef CONFIG_CRASH_CORE 71 static inline bool fw_cfg_dma_enabled(void) 72 { 73 return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma; 74 } 75 76 /* qemu fw_cfg device is sync today, but spec says it may become async */ 77 static void fw_cfg_wait_for_control(struct fw_cfg_dma_access *d) 78 { 79 for (;;) { 80 u32 ctrl = be32_to_cpu(READ_ONCE(d->control)); 81 82 /* do not reorder the read to d->control */ 83 rmb(); 84 if ((ctrl & ~FW_CFG_DMA_CTL_ERROR) == 0) 85 return; 86 87 cpu_relax(); 88 } 89 } 90 91 static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control) 92 { 93 phys_addr_t dma; 94 struct fw_cfg_dma_access *d = NULL; 95 ssize_t ret = length; 96 97 d = kmalloc(sizeof(*d), GFP_KERNEL); 98 if (!d) { 99 ret = -ENOMEM; 100 goto end; 101 } 102 103 /* fw_cfg device does not need IOMMU protection, so use physical addresses */ 104 *d = (struct fw_cfg_dma_access) { 105 .address = cpu_to_be64(address ? virt_to_phys(address) : 0), 106 .length = cpu_to_be32(length), 107 .control = cpu_to_be32(control) 108 }; 109 110 dma = virt_to_phys(d); 111 112 iowrite32be((u64)dma >> 32, fw_cfg_reg_dma); 113 /* force memory to sync before notifying device via MMIO */ 114 wmb(); 115 iowrite32be(dma, fw_cfg_reg_dma + 4); 116 117 fw_cfg_wait_for_control(d); 118 119 if (be32_to_cpu(READ_ONCE(d->control)) & FW_CFG_DMA_CTL_ERROR) { 120 ret = -EIO; 121 } 122 123 end: 124 kfree(d); 125 126 return ret; 127 } 128 #endif 129 130 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ 131 static ssize_t fw_cfg_read_blob(u16 key, 132 void *buf, loff_t pos, size_t count) 133 { 134 u32 glk = -1U; 135 acpi_status status; 136 137 /* If we have ACPI, ensure mutual exclusion against any potential 138 * device access by the firmware, e.g. via AML methods: 139 */ 140 status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); 141 if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { 142 /* Should never get here */ 143 WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n"); 144 memset(buf, 0, count); 145 return -EINVAL; 146 } 147 148 mutex_lock(&fw_cfg_dev_lock); 149 fw_cfg_sel_endianness(key); 150 while (pos-- > 0) 151 ioread8(fw_cfg_reg_data); 152 ioread8_rep(fw_cfg_reg_data, buf, count); 153 mutex_unlock(&fw_cfg_dev_lock); 154 155 acpi_release_global_lock(glk); 156 return count; 157 } 158 159 #ifdef CONFIG_CRASH_CORE 160 /* write chunk of given fw_cfg blob (caller responsible for sanity-check) */ 161 static ssize_t fw_cfg_write_blob(u16 key, 162 void *buf, loff_t pos, size_t count) 163 { 164 u32 glk = -1U; 165 acpi_status status; 166 ssize_t ret = count; 167 168 /* If we have ACPI, ensure mutual exclusion against any potential 169 * device access by the firmware, e.g. via AML methods: 170 */ 171 status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); 172 if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { 173 /* Should never get here */ 174 WARN(1, "%s: Failed to lock ACPI!\n", __func__); 175 return -EINVAL; 176 } 177 178 mutex_lock(&fw_cfg_dev_lock); 179 if (pos == 0) { 180 ret = fw_cfg_dma_transfer(buf, count, key << 16 181 | FW_CFG_DMA_CTL_SELECT 182 | FW_CFG_DMA_CTL_WRITE); 183 } else { 184 fw_cfg_sel_endianness(key); 185 ret = fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP); 186 if (ret < 0) 187 goto end; 188 ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE); 189 } 190 191 end: 192 mutex_unlock(&fw_cfg_dev_lock); 193 194 acpi_release_global_lock(glk); 195 196 return ret; 197 } 198 #endif /* CONFIG_CRASH_CORE */ 199 200 /* clean up fw_cfg device i/o */ 201 static void fw_cfg_io_cleanup(void) 202 { 203 if (fw_cfg_is_mmio) { 204 iounmap(fw_cfg_dev_base); 205 release_mem_region(fw_cfg_p_base, fw_cfg_p_size); 206 } else { 207 ioport_unmap(fw_cfg_dev_base); 208 release_region(fw_cfg_p_base, fw_cfg_p_size); 209 } 210 } 211 212 /* arch-specific ctrl & data register offsets are not available in ACPI, DT */ 213 #if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF)) 214 # if (defined(CONFIG_ARM) || defined(CONFIG_ARM64)) 215 # define FW_CFG_CTRL_OFF 0x08 216 # define FW_CFG_DATA_OFF 0x00 217 # define FW_CFG_DMA_OFF 0x10 218 # elif defined(CONFIG_PARISC) /* parisc */ 219 # define FW_CFG_CTRL_OFF 0x00 220 # define FW_CFG_DATA_OFF 0x04 221 # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */ 222 # define FW_CFG_CTRL_OFF 0x00 223 # define FW_CFG_DATA_OFF 0x02 224 # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */ 225 # define FW_CFG_CTRL_OFF 0x00 226 # define FW_CFG_DATA_OFF 0x01 227 # define FW_CFG_DMA_OFF 0x04 228 # else 229 # error "QEMU FW_CFG not available on this architecture!" 230 # endif 231 #endif 232 233 /* initialize fw_cfg device i/o from platform data */ 234 static int fw_cfg_do_platform_probe(struct platform_device *pdev) 235 { 236 char sig[FW_CFG_SIG_SIZE]; 237 struct resource *range, *ctrl, *data, *dma; 238 239 /* acquire i/o range details */ 240 fw_cfg_is_mmio = false; 241 range = platform_get_resource(pdev, IORESOURCE_IO, 0); 242 if (!range) { 243 fw_cfg_is_mmio = true; 244 range = platform_get_resource(pdev, IORESOURCE_MEM, 0); 245 if (!range) 246 return -EINVAL; 247 } 248 fw_cfg_p_base = range->start; 249 fw_cfg_p_size = resource_size(range); 250 251 if (fw_cfg_is_mmio) { 252 if (!request_mem_region(fw_cfg_p_base, 253 fw_cfg_p_size, "fw_cfg_mem")) 254 return -EBUSY; 255 fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size); 256 if (!fw_cfg_dev_base) { 257 release_mem_region(fw_cfg_p_base, fw_cfg_p_size); 258 return -EFAULT; 259 } 260 } else { 261 if (!request_region(fw_cfg_p_base, 262 fw_cfg_p_size, "fw_cfg_io")) 263 return -EBUSY; 264 fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size); 265 if (!fw_cfg_dev_base) { 266 release_region(fw_cfg_p_base, fw_cfg_p_size); 267 return -EFAULT; 268 } 269 } 270 271 /* were custom register offsets provided (e.g. on the command line)? */ 272 ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl"); 273 data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data"); 274 dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma"); 275 if (ctrl && data) { 276 fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start; 277 fw_cfg_reg_data = fw_cfg_dev_base + data->start; 278 } else { 279 /* use architecture-specific offsets */ 280 fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF; 281 fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF; 282 } 283 284 if (dma) 285 fw_cfg_reg_dma = fw_cfg_dev_base + dma->start; 286 #ifdef FW_CFG_DMA_OFF 287 else 288 fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF; 289 #endif 290 291 /* verify fw_cfg device signature */ 292 if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 293 0, FW_CFG_SIG_SIZE) < 0 || 294 memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) { 295 fw_cfg_io_cleanup(); 296 return -ENODEV; 297 } 298 299 return 0; 300 } 301 302 static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a, 303 char *buf) 304 { 305 return sprintf(buf, "%u\n", fw_cfg_rev); 306 } 307 308 static const struct kobj_attribute fw_cfg_rev_attr = { 309 .attr = { .name = "rev", .mode = S_IRUSR }, 310 .show = fw_cfg_showrev, 311 }; 312 313 /* fw_cfg_sysfs_entry type */ 314 struct fw_cfg_sysfs_entry { 315 struct kobject kobj; 316 u32 size; 317 u16 select; 318 char name[FW_CFG_MAX_FILE_PATH]; 319 struct list_head list; 320 }; 321 322 #ifdef CONFIG_CRASH_CORE 323 static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f) 324 { 325 static struct fw_cfg_vmcoreinfo *data; 326 ssize_t ret; 327 328 data = kmalloc(sizeof(struct fw_cfg_vmcoreinfo), GFP_KERNEL); 329 if (!data) 330 return -ENOMEM; 331 332 *data = (struct fw_cfg_vmcoreinfo) { 333 .guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF), 334 .size = cpu_to_le32(VMCOREINFO_NOTE_SIZE), 335 .paddr = cpu_to_le64(paddr_vmcoreinfo_note()) 336 }; 337 /* spare ourself reading host format support for now since we 338 * don't know what else to format - host may ignore ours 339 */ 340 ret = fw_cfg_write_blob(be16_to_cpu(f->select), data, 341 0, sizeof(struct fw_cfg_vmcoreinfo)); 342 343 kfree(data); 344 return ret; 345 } 346 #endif /* CONFIG_CRASH_CORE */ 347 348 /* get fw_cfg_sysfs_entry from kobject member */ 349 static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj) 350 { 351 return container_of(kobj, struct fw_cfg_sysfs_entry, kobj); 352 } 353 354 /* fw_cfg_sysfs_attribute type */ 355 struct fw_cfg_sysfs_attribute { 356 struct attribute attr; 357 ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf); 358 }; 359 360 /* get fw_cfg_sysfs_attribute from attribute member */ 361 static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr) 362 { 363 return container_of(attr, struct fw_cfg_sysfs_attribute, attr); 364 } 365 366 /* global cache of fw_cfg_sysfs_entry objects */ 367 static LIST_HEAD(fw_cfg_entry_cache); 368 369 /* kobjects removed lazily by kernel, mutual exclusion needed */ 370 static DEFINE_SPINLOCK(fw_cfg_cache_lock); 371 372 static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry) 373 { 374 spin_lock(&fw_cfg_cache_lock); 375 list_add_tail(&entry->list, &fw_cfg_entry_cache); 376 spin_unlock(&fw_cfg_cache_lock); 377 } 378 379 static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry) 380 { 381 spin_lock(&fw_cfg_cache_lock); 382 list_del(&entry->list); 383 spin_unlock(&fw_cfg_cache_lock); 384 } 385 386 static void fw_cfg_sysfs_cache_cleanup(void) 387 { 388 struct fw_cfg_sysfs_entry *entry, *next; 389 390 list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { 391 fw_cfg_sysfs_cache_delist(entry); 392 kobject_put(&entry->kobj); 393 } 394 } 395 396 /* default_attrs: per-entry attributes and show methods */ 397 398 #define FW_CFG_SYSFS_ATTR(_attr) \ 399 struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \ 400 .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \ 401 .show = fw_cfg_sysfs_show_##_attr, \ 402 } 403 404 static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf) 405 { 406 return sprintf(buf, "%u\n", e->size); 407 } 408 409 static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) 410 { 411 return sprintf(buf, "%u\n", e->select); 412 } 413 414 static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) 415 { 416 return sprintf(buf, "%s\n", e->name); 417 } 418 419 static FW_CFG_SYSFS_ATTR(size); 420 static FW_CFG_SYSFS_ATTR(key); 421 static FW_CFG_SYSFS_ATTR(name); 422 423 static struct attribute *fw_cfg_sysfs_entry_attrs[] = { 424 &fw_cfg_sysfs_attr_size.attr, 425 &fw_cfg_sysfs_attr_key.attr, 426 &fw_cfg_sysfs_attr_name.attr, 427 NULL, 428 }; 429 430 /* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */ 431 static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a, 432 char *buf) 433 { 434 struct fw_cfg_sysfs_entry *entry = to_entry(kobj); 435 struct fw_cfg_sysfs_attribute *attr = to_attr(a); 436 437 return attr->show(entry, buf); 438 } 439 440 static const struct sysfs_ops fw_cfg_sysfs_attr_ops = { 441 .show = fw_cfg_sysfs_attr_show, 442 }; 443 444 /* release: destructor, to be called via kobject_put() */ 445 static void fw_cfg_sysfs_release_entry(struct kobject *kobj) 446 { 447 struct fw_cfg_sysfs_entry *entry = to_entry(kobj); 448 449 kfree(entry); 450 } 451 452 /* kobj_type: ties together all properties required to register an entry */ 453 static struct kobj_type fw_cfg_sysfs_entry_ktype = { 454 .default_attrs = fw_cfg_sysfs_entry_attrs, 455 .sysfs_ops = &fw_cfg_sysfs_attr_ops, 456 .release = fw_cfg_sysfs_release_entry, 457 }; 458 459 /* raw-read method and attribute */ 460 static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj, 461 struct bin_attribute *bin_attr, 462 char *buf, loff_t pos, size_t count) 463 { 464 struct fw_cfg_sysfs_entry *entry = to_entry(kobj); 465 466 if (pos > entry->size) 467 return -EINVAL; 468 469 if (count > entry->size - pos) 470 count = entry->size - pos; 471 472 return fw_cfg_read_blob(entry->select, buf, pos, count); 473 } 474 475 static struct bin_attribute fw_cfg_sysfs_attr_raw = { 476 .attr = { .name = "raw", .mode = S_IRUSR }, 477 .read = fw_cfg_sysfs_read_raw, 478 }; 479 480 /* 481 * Create a kset subdirectory matching each '/' delimited dirname token 482 * in 'name', starting with sysfs kset/folder 'dir'; At the end, create 483 * a symlink directed at the given 'target'. 484 * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed 485 * to be a well-behaved path name. Whenever a symlink vs. kset directory 486 * name collision occurs, the kernel will issue big scary warnings while 487 * refusing to add the offending link or directory. We follow up with our 488 * own, slightly less scary error messages explaining the situation :) 489 */ 490 static int fw_cfg_build_symlink(struct kset *dir, 491 struct kobject *target, const char *name) 492 { 493 int ret; 494 struct kset *subdir; 495 struct kobject *ko; 496 char *name_copy, *p, *tok; 497 498 if (!dir || !target || !name || !*name) 499 return -EINVAL; 500 501 /* clone a copy of name for parsing */ 502 name_copy = p = kstrdup(name, GFP_KERNEL); 503 if (!name_copy) 504 return -ENOMEM; 505 506 /* create folders for each dirname token, then symlink for basename */ 507 while ((tok = strsep(&p, "/")) && *tok) { 508 509 /* last (basename) token? If so, add symlink here */ 510 if (!p || !*p) { 511 ret = sysfs_create_link(&dir->kobj, target, tok); 512 break; 513 } 514 515 /* does the current dir contain an item named after tok ? */ 516 ko = kset_find_obj(dir, tok); 517 if (ko) { 518 /* drop reference added by kset_find_obj */ 519 kobject_put(ko); 520 521 /* ko MUST be a kset - we're about to use it as one ! */ 522 if (ko->ktype != dir->kobj.ktype) { 523 ret = -EINVAL; 524 break; 525 } 526 527 /* descend into already existing subdirectory */ 528 dir = to_kset(ko); 529 } else { 530 /* create new subdirectory kset */ 531 subdir = kzalloc(sizeof(struct kset), GFP_KERNEL); 532 if (!subdir) { 533 ret = -ENOMEM; 534 break; 535 } 536 subdir->kobj.kset = dir; 537 subdir->kobj.ktype = dir->kobj.ktype; 538 ret = kobject_set_name(&subdir->kobj, "%s", tok); 539 if (ret) { 540 kfree(subdir); 541 break; 542 } 543 ret = kset_register(subdir); 544 if (ret) { 545 kfree(subdir); 546 break; 547 } 548 549 /* descend into newly created subdirectory */ 550 dir = subdir; 551 } 552 } 553 554 /* we're done with cloned copy of name */ 555 kfree(name_copy); 556 return ret; 557 } 558 559 /* recursively unregister fw_cfg/by_name/ kset directory tree */ 560 static void fw_cfg_kset_unregister_recursive(struct kset *kset) 561 { 562 struct kobject *k, *next; 563 564 list_for_each_entry_safe(k, next, &kset->list, entry) 565 /* all set members are ksets too, but check just in case... */ 566 if (k->ktype == kset->kobj.ktype) 567 fw_cfg_kset_unregister_recursive(to_kset(k)); 568 569 /* symlinks are cleanly and automatically removed with the directory */ 570 kset_unregister(kset); 571 } 572 573 /* kobjects & kset representing top-level, by_key, and by_name folders */ 574 static struct kobject *fw_cfg_top_ko; 575 static struct kobject *fw_cfg_sel_ko; 576 static struct kset *fw_cfg_fname_kset; 577 578 /* register an individual fw_cfg file */ 579 static int fw_cfg_register_file(const struct fw_cfg_file *f) 580 { 581 int err; 582 struct fw_cfg_sysfs_entry *entry; 583 584 #ifdef CONFIG_CRASH_CORE 585 if (fw_cfg_dma_enabled() && 586 strcmp(f->name, FW_CFG_VMCOREINFO_FILENAME) == 0 && 587 !is_kdump_kernel()) { 588 if (fw_cfg_write_vmcoreinfo(f) < 0) 589 pr_warn("fw_cfg: failed to write vmcoreinfo"); 590 } 591 #endif 592 593 /* allocate new entry */ 594 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 595 if (!entry) 596 return -ENOMEM; 597 598 /* set file entry information */ 599 entry->size = be32_to_cpu(f->size); 600 entry->select = be16_to_cpu(f->select); 601 strscpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH); 602 603 /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */ 604 err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype, 605 fw_cfg_sel_ko, "%d", entry->select); 606 if (err) 607 goto err_put_entry; 608 609 /* add raw binary content access */ 610 err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); 611 if (err) 612 goto err_del_entry; 613 614 /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */ 615 fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name); 616 617 /* success, add entry to global cache */ 618 fw_cfg_sysfs_cache_enlist(entry); 619 return 0; 620 621 err_del_entry: 622 kobject_del(&entry->kobj); 623 err_put_entry: 624 kobject_put(&entry->kobj); 625 return err; 626 } 627 628 /* iterate over all fw_cfg directory entries, registering each one */ 629 static int fw_cfg_register_dir_entries(void) 630 { 631 int ret = 0; 632 __be32 files_count; 633 u32 count, i; 634 struct fw_cfg_file *dir; 635 size_t dir_size; 636 637 ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count, 638 0, sizeof(files_count)); 639 if (ret < 0) 640 return ret; 641 642 count = be32_to_cpu(files_count); 643 dir_size = count * sizeof(struct fw_cfg_file); 644 645 dir = kmalloc(dir_size, GFP_KERNEL); 646 if (!dir) 647 return -ENOMEM; 648 649 ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, 650 sizeof(files_count), dir_size); 651 if (ret < 0) 652 goto end; 653 654 for (i = 0; i < count; i++) { 655 ret = fw_cfg_register_file(&dir[i]); 656 if (ret) 657 break; 658 } 659 660 end: 661 kfree(dir); 662 return ret; 663 } 664 665 /* unregister top-level or by_key folder */ 666 static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) 667 { 668 kobject_del(kobj); 669 kobject_put(kobj); 670 } 671 672 static int fw_cfg_sysfs_probe(struct platform_device *pdev) 673 { 674 int err; 675 __le32 rev; 676 677 /* NOTE: If we supported multiple fw_cfg devices, we'd first create 678 * a subdirectory named after e.g. pdev->id, then hang per-device 679 * by_key (and by_name) subdirectories underneath it. However, only 680 * one fw_cfg device exist system-wide, so if one was already found 681 * earlier, we might as well stop here. 682 */ 683 if (fw_cfg_sel_ko) 684 return -EBUSY; 685 686 /* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */ 687 err = -ENOMEM; 688 fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko); 689 if (!fw_cfg_sel_ko) 690 goto err_sel; 691 fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko); 692 if (!fw_cfg_fname_kset) 693 goto err_name; 694 695 /* initialize fw_cfg device i/o from platform data */ 696 err = fw_cfg_do_platform_probe(pdev); 697 if (err) 698 goto err_probe; 699 700 /* get revision number, add matching top-level attribute */ 701 err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev)); 702 if (err < 0) 703 goto err_probe; 704 705 fw_cfg_rev = le32_to_cpu(rev); 706 err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 707 if (err) 708 goto err_rev; 709 710 /* process fw_cfg file directory entry, registering each file */ 711 err = fw_cfg_register_dir_entries(); 712 if (err) 713 goto err_dir; 714 715 /* success */ 716 pr_debug("fw_cfg: loaded.\n"); 717 return 0; 718 719 err_dir: 720 fw_cfg_sysfs_cache_cleanup(); 721 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 722 err_rev: 723 fw_cfg_io_cleanup(); 724 err_probe: 725 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); 726 err_name: 727 fw_cfg_kobj_cleanup(fw_cfg_sel_ko); 728 err_sel: 729 return err; 730 } 731 732 static int fw_cfg_sysfs_remove(struct platform_device *pdev) 733 { 734 pr_debug("fw_cfg: unloading.\n"); 735 fw_cfg_sysfs_cache_cleanup(); 736 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 737 fw_cfg_io_cleanup(); 738 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); 739 fw_cfg_kobj_cleanup(fw_cfg_sel_ko); 740 return 0; 741 } 742 743 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = { 744 { .compatible = "qemu,fw-cfg-mmio", }, 745 {}, 746 }; 747 MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match); 748 749 #ifdef CONFIG_ACPI 750 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = { 751 { FW_CFG_ACPI_DEVICE_ID, }, 752 {}, 753 }; 754 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match); 755 #endif 756 757 static struct platform_driver fw_cfg_sysfs_driver = { 758 .probe = fw_cfg_sysfs_probe, 759 .remove = fw_cfg_sysfs_remove, 760 .driver = { 761 .name = "fw_cfg", 762 .of_match_table = fw_cfg_sysfs_mmio_match, 763 .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match), 764 }, 765 }; 766 767 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE 768 769 static struct platform_device *fw_cfg_cmdline_dev; 770 771 /* this probably belongs in e.g. include/linux/types.h, 772 * but right now we are the only ones doing it... 773 */ 774 #ifdef CONFIG_PHYS_ADDR_T_64BIT 775 #define __PHYS_ADDR_PREFIX "ll" 776 #else 777 #define __PHYS_ADDR_PREFIX "" 778 #endif 779 780 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */ 781 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \ 782 ":%" __PHYS_ADDR_PREFIX "i" \ 783 ":%" __PHYS_ADDR_PREFIX "i%n" \ 784 ":%" __PHYS_ADDR_PREFIX "i%n" 785 786 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \ 787 "0x%" __PHYS_ADDR_PREFIX "x" 788 789 #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \ 790 ":%" __PHYS_ADDR_PREFIX "u" \ 791 ":%" __PHYS_ADDR_PREFIX "u" 792 793 #define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \ 794 ":%" __PHYS_ADDR_PREFIX "u" 795 796 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) 797 { 798 struct resource res[4] = {}; 799 char *str; 800 phys_addr_t base; 801 resource_size_t size, ctrl_off, data_off, dma_off; 802 int processed, consumed = 0; 803 804 /* only one fw_cfg device can exist system-wide, so if one 805 * was processed on the command line already, we might as 806 * well stop here. 807 */ 808 if (fw_cfg_cmdline_dev) { 809 /* avoid leaking previously registered device */ 810 platform_device_unregister(fw_cfg_cmdline_dev); 811 return -EINVAL; 812 } 813 814 /* consume "<size>" portion of command line argument */ 815 size = memparse(arg, &str); 816 817 /* get "@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */ 818 processed = sscanf(str, PH_ADDR_SCAN_FMT, 819 &base, &consumed, 820 &ctrl_off, &data_off, &consumed, 821 &dma_off, &consumed); 822 823 /* sscanf() must process precisely 1, 3 or 4 chunks: 824 * <base> is mandatory, optionally followed by <ctrl_off> 825 * and <data_off>, and <dma_off>; 826 * there must be no extra characters after the last chunk, 827 * so str[consumed] must be '\0'. 828 */ 829 if (str[consumed] || 830 (processed != 1 && processed != 3 && processed != 4)) 831 return -EINVAL; 832 833 res[0].start = base; 834 res[0].end = base + size - 1; 835 res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM : 836 IORESOURCE_IO; 837 838 /* insert register offsets, if provided */ 839 if (processed > 1) { 840 res[1].name = "ctrl"; 841 res[1].start = ctrl_off; 842 res[1].flags = IORESOURCE_REG; 843 res[2].name = "data"; 844 res[2].start = data_off; 845 res[2].flags = IORESOURCE_REG; 846 } 847 if (processed > 3) { 848 res[3].name = "dma"; 849 res[3].start = dma_off; 850 res[3].flags = IORESOURCE_REG; 851 } 852 853 /* "processed" happens to nicely match the number of resources 854 * we need to pass in to this platform device. 855 */ 856 fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg", 857 PLATFORM_DEVID_NONE, res, processed); 858 859 return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev); 860 } 861 862 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp) 863 { 864 /* stay silent if device was not configured via the command 865 * line, or if the parameter name (ioport/mmio) doesn't match 866 * the device setting 867 */ 868 if (!fw_cfg_cmdline_dev || 869 (!strcmp(kp->name, "mmio") ^ 870 (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM))) 871 return 0; 872 873 switch (fw_cfg_cmdline_dev->num_resources) { 874 case 1: 875 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT, 876 resource_size(&fw_cfg_cmdline_dev->resource[0]), 877 fw_cfg_cmdline_dev->resource[0].start); 878 case 3: 879 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT, 880 resource_size(&fw_cfg_cmdline_dev->resource[0]), 881 fw_cfg_cmdline_dev->resource[0].start, 882 fw_cfg_cmdline_dev->resource[1].start, 883 fw_cfg_cmdline_dev->resource[2].start); 884 case 4: 885 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT, 886 resource_size(&fw_cfg_cmdline_dev->resource[0]), 887 fw_cfg_cmdline_dev->resource[0].start, 888 fw_cfg_cmdline_dev->resource[1].start, 889 fw_cfg_cmdline_dev->resource[2].start, 890 fw_cfg_cmdline_dev->resource[3].start); 891 } 892 893 /* Should never get here */ 894 WARN(1, "Unexpected number of resources: %d\n", 895 fw_cfg_cmdline_dev->num_resources); 896 return 0; 897 } 898 899 static const struct kernel_param_ops fw_cfg_cmdline_param_ops = { 900 .set = fw_cfg_cmdline_set, 901 .get = fw_cfg_cmdline_get, 902 }; 903 904 device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); 905 device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); 906 907 #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */ 908 909 static int __init fw_cfg_sysfs_init(void) 910 { 911 int ret; 912 913 /* create /sys/firmware/qemu_fw_cfg/ top level directory */ 914 fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj); 915 if (!fw_cfg_top_ko) 916 return -ENOMEM; 917 918 ret = platform_driver_register(&fw_cfg_sysfs_driver); 919 if (ret) 920 fw_cfg_kobj_cleanup(fw_cfg_top_ko); 921 922 return ret; 923 } 924 925 static void __exit fw_cfg_sysfs_exit(void) 926 { 927 platform_driver_unregister(&fw_cfg_sysfs_driver); 928 929 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE 930 platform_device_unregister(fw_cfg_cmdline_dev); 931 #endif 932 933 /* clean up /sys/firmware/qemu_fw_cfg/ */ 934 fw_cfg_kobj_cleanup(fw_cfg_top_ko); 935 } 936 937 module_init(fw_cfg_sysfs_init); 938 module_exit(fw_cfg_sysfs_exit); 939