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 memcpy(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 kobject_put(&entry->kobj); 608 return err; 609 } 610 611 /* add raw binary content access */ 612 err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); 613 if (err) 614 goto err_add_raw; 615 616 /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */ 617 fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name); 618 619 /* success, add entry to global cache */ 620 fw_cfg_sysfs_cache_enlist(entry); 621 return 0; 622 623 err_add_raw: 624 kobject_del(&entry->kobj); 625 kfree(entry); 626 return err; 627 } 628 629 /* iterate over all fw_cfg directory entries, registering each one */ 630 static int fw_cfg_register_dir_entries(void) 631 { 632 int ret = 0; 633 __be32 files_count; 634 u32 count, i; 635 struct fw_cfg_file *dir; 636 size_t dir_size; 637 638 ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count, 639 0, sizeof(files_count)); 640 if (ret < 0) 641 return ret; 642 643 count = be32_to_cpu(files_count); 644 dir_size = count * sizeof(struct fw_cfg_file); 645 646 dir = kmalloc(dir_size, GFP_KERNEL); 647 if (!dir) 648 return -ENOMEM; 649 650 ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, 651 sizeof(files_count), dir_size); 652 if (ret < 0) 653 goto end; 654 655 for (i = 0; i < count; i++) { 656 ret = fw_cfg_register_file(&dir[i]); 657 if (ret) 658 break; 659 } 660 661 end: 662 kfree(dir); 663 return ret; 664 } 665 666 /* unregister top-level or by_key folder */ 667 static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) 668 { 669 kobject_del(kobj); 670 kobject_put(kobj); 671 } 672 673 static int fw_cfg_sysfs_probe(struct platform_device *pdev) 674 { 675 int err; 676 __le32 rev; 677 678 /* NOTE: If we supported multiple fw_cfg devices, we'd first create 679 * a subdirectory named after e.g. pdev->id, then hang per-device 680 * by_key (and by_name) subdirectories underneath it. However, only 681 * one fw_cfg device exist system-wide, so if one was already found 682 * earlier, we might as well stop here. 683 */ 684 if (fw_cfg_sel_ko) 685 return -EBUSY; 686 687 /* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */ 688 err = -ENOMEM; 689 fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko); 690 if (!fw_cfg_sel_ko) 691 goto err_sel; 692 fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko); 693 if (!fw_cfg_fname_kset) 694 goto err_name; 695 696 /* initialize fw_cfg device i/o from platform data */ 697 err = fw_cfg_do_platform_probe(pdev); 698 if (err) 699 goto err_probe; 700 701 /* get revision number, add matching top-level attribute */ 702 err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev)); 703 if (err < 0) 704 goto err_probe; 705 706 fw_cfg_rev = le32_to_cpu(rev); 707 err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 708 if (err) 709 goto err_rev; 710 711 /* process fw_cfg file directory entry, registering each file */ 712 err = fw_cfg_register_dir_entries(); 713 if (err) 714 goto err_dir; 715 716 /* success */ 717 pr_debug("fw_cfg: loaded.\n"); 718 return 0; 719 720 err_dir: 721 fw_cfg_sysfs_cache_cleanup(); 722 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 723 err_rev: 724 fw_cfg_io_cleanup(); 725 err_probe: 726 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); 727 err_name: 728 fw_cfg_kobj_cleanup(fw_cfg_sel_ko); 729 err_sel: 730 return err; 731 } 732 733 static int fw_cfg_sysfs_remove(struct platform_device *pdev) 734 { 735 pr_debug("fw_cfg: unloading.\n"); 736 fw_cfg_sysfs_cache_cleanup(); 737 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); 738 fw_cfg_io_cleanup(); 739 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); 740 fw_cfg_kobj_cleanup(fw_cfg_sel_ko); 741 return 0; 742 } 743 744 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = { 745 { .compatible = "qemu,fw-cfg-mmio", }, 746 {}, 747 }; 748 MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match); 749 750 #ifdef CONFIG_ACPI 751 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = { 752 { FW_CFG_ACPI_DEVICE_ID, }, 753 {}, 754 }; 755 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match); 756 #endif 757 758 static struct platform_driver fw_cfg_sysfs_driver = { 759 .probe = fw_cfg_sysfs_probe, 760 .remove = fw_cfg_sysfs_remove, 761 .driver = { 762 .name = "fw_cfg", 763 .of_match_table = fw_cfg_sysfs_mmio_match, 764 .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match), 765 }, 766 }; 767 768 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE 769 770 static struct platform_device *fw_cfg_cmdline_dev; 771 772 /* this probably belongs in e.g. include/linux/types.h, 773 * but right now we are the only ones doing it... 774 */ 775 #ifdef CONFIG_PHYS_ADDR_T_64BIT 776 #define __PHYS_ADDR_PREFIX "ll" 777 #else 778 #define __PHYS_ADDR_PREFIX "" 779 #endif 780 781 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */ 782 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \ 783 ":%" __PHYS_ADDR_PREFIX "i" \ 784 ":%" __PHYS_ADDR_PREFIX "i%n" \ 785 ":%" __PHYS_ADDR_PREFIX "i%n" 786 787 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \ 788 "0x%" __PHYS_ADDR_PREFIX "x" 789 790 #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \ 791 ":%" __PHYS_ADDR_PREFIX "u" \ 792 ":%" __PHYS_ADDR_PREFIX "u" 793 794 #define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \ 795 ":%" __PHYS_ADDR_PREFIX "u" 796 797 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) 798 { 799 struct resource res[4] = {}; 800 char *str; 801 phys_addr_t base; 802 resource_size_t size, ctrl_off, data_off, dma_off; 803 int processed, consumed = 0; 804 805 /* only one fw_cfg device can exist system-wide, so if one 806 * was processed on the command line already, we might as 807 * well stop here. 808 */ 809 if (fw_cfg_cmdline_dev) { 810 /* avoid leaking previously registered device */ 811 platform_device_unregister(fw_cfg_cmdline_dev); 812 return -EINVAL; 813 } 814 815 /* consume "<size>" portion of command line argument */ 816 size = memparse(arg, &str); 817 818 /* get "@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */ 819 processed = sscanf(str, PH_ADDR_SCAN_FMT, 820 &base, &consumed, 821 &ctrl_off, &data_off, &consumed, 822 &dma_off, &consumed); 823 824 /* sscanf() must process precisely 1, 3 or 4 chunks: 825 * <base> is mandatory, optionally followed by <ctrl_off> 826 * and <data_off>, and <dma_off>; 827 * there must be no extra characters after the last chunk, 828 * so str[consumed] must be '\0'. 829 */ 830 if (str[consumed] || 831 (processed != 1 && processed != 3 && processed != 4)) 832 return -EINVAL; 833 834 res[0].start = base; 835 res[0].end = base + size - 1; 836 res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM : 837 IORESOURCE_IO; 838 839 /* insert register offsets, if provided */ 840 if (processed > 1) { 841 res[1].name = "ctrl"; 842 res[1].start = ctrl_off; 843 res[1].flags = IORESOURCE_REG; 844 res[2].name = "data"; 845 res[2].start = data_off; 846 res[2].flags = IORESOURCE_REG; 847 } 848 if (processed > 3) { 849 res[3].name = "dma"; 850 res[3].start = dma_off; 851 res[3].flags = IORESOURCE_REG; 852 } 853 854 /* "processed" happens to nicely match the number of resources 855 * we need to pass in to this platform device. 856 */ 857 fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg", 858 PLATFORM_DEVID_NONE, res, processed); 859 860 return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev); 861 } 862 863 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp) 864 { 865 /* stay silent if device was not configured via the command 866 * line, or if the parameter name (ioport/mmio) doesn't match 867 * the device setting 868 */ 869 if (!fw_cfg_cmdline_dev || 870 (!strcmp(kp->name, "mmio") ^ 871 (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM))) 872 return 0; 873 874 switch (fw_cfg_cmdline_dev->num_resources) { 875 case 1: 876 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT, 877 resource_size(&fw_cfg_cmdline_dev->resource[0]), 878 fw_cfg_cmdline_dev->resource[0].start); 879 case 3: 880 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT, 881 resource_size(&fw_cfg_cmdline_dev->resource[0]), 882 fw_cfg_cmdline_dev->resource[0].start, 883 fw_cfg_cmdline_dev->resource[1].start, 884 fw_cfg_cmdline_dev->resource[2].start); 885 case 4: 886 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT, 887 resource_size(&fw_cfg_cmdline_dev->resource[0]), 888 fw_cfg_cmdline_dev->resource[0].start, 889 fw_cfg_cmdline_dev->resource[1].start, 890 fw_cfg_cmdline_dev->resource[2].start, 891 fw_cfg_cmdline_dev->resource[3].start); 892 } 893 894 /* Should never get here */ 895 WARN(1, "Unexpected number of resources: %d\n", 896 fw_cfg_cmdline_dev->num_resources); 897 return 0; 898 } 899 900 static const struct kernel_param_ops fw_cfg_cmdline_param_ops = { 901 .set = fw_cfg_cmdline_set, 902 .get = fw_cfg_cmdline_get, 903 }; 904 905 device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); 906 device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); 907 908 #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */ 909 910 static int __init fw_cfg_sysfs_init(void) 911 { 912 int ret; 913 914 /* create /sys/firmware/qemu_fw_cfg/ top level directory */ 915 fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj); 916 if (!fw_cfg_top_ko) 917 return -ENOMEM; 918 919 ret = platform_driver_register(&fw_cfg_sysfs_driver); 920 if (ret) 921 fw_cfg_kobj_cleanup(fw_cfg_top_ko); 922 923 return ret; 924 } 925 926 static void __exit fw_cfg_sysfs_exit(void) 927 { 928 platform_driver_unregister(&fw_cfg_sysfs_driver); 929 930 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE 931 platform_device_unregister(fw_cfg_cmdline_dev); 932 #endif 933 934 /* clean up /sys/firmware/qemu_fw_cfg/ */ 935 fw_cfg_kobj_cleanup(fw_cfg_top_ko); 936 } 937 938 module_init(fw_cfg_sysfs_init); 939 module_exit(fw_cfg_sysfs_exit); 940