drivers/firmware/qemu_fw_cfg.c

   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  *      [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
  14  * or
  15  *      [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_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  *
  23  * e.g.:
  24  *      fw_cfg.ioport=2@0x510:0:1               (the default on x86)
  25  * or
  26  *      fw_cfg.mmio=0xA@0x9020000:8:0           (the default on arm)
  27  */
  28
  29 #include <linux/module.h>
  30 #include <linux/platform_device.h>
  31 #include <linux/acpi.h>
  32 #include <linux/slab.h>
  33 #include <linux/io.h>
  34 #include <linux/ioport.h>
  35
  36 MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
  37 MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
  38 MODULE_LICENSE("GPL");
  39
  40 /* selector key values for "well-known" fw_cfg entries */
  41 #define FW_CFG_SIGNATURE  0x00
  42 #define FW_CFG_ID         0x01
  43 #define FW_CFG_FILE_DIR   0x19
  44
  45 /* size in bytes of fw_cfg signature */
  46 #define FW_CFG_SIG_SIZE 4
  47
  48 /* fw_cfg "file name" is up to 56 characters (including terminating nul) */
  49 #define FW_CFG_MAX_FILE_PATH 56
  50
  51 /* fw_cfg file directory entry type */
  52 struct fw_cfg_file {
  53         u32 size;
  54         u16 select;
  55         u16 reserved;
  56         char name[FW_CFG_MAX_FILE_PATH];
  57 };
  58
  59 /* fw_cfg device i/o register addresses */
  60 static bool fw_cfg_is_mmio;
  61 static phys_addr_t fw_cfg_p_base;
  62 static resource_size_t fw_cfg_p_size;
  63 static void __iomem *fw_cfg_dev_base;
  64 static void __iomem *fw_cfg_reg_ctrl;
  65 static void __iomem *fw_cfg_reg_data;
  66
  67 /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
  68 static DEFINE_MUTEX(fw_cfg_dev_lock);
  69
  70 /* pick appropriate endianness for selector key */
  71 static inline u16 fw_cfg_sel_endianness(u16 key)
  72 {
  73         return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
  74 }
  75
  76 /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
  77 static inline void fw_cfg_read_blob(u16 key,
  78                                     void *buf, loff_t pos, size_t count)
  79 {
  80         mutex_lock(&fw_cfg_dev_lock);
  81         iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
  82         while (pos-- > 0)
  83                 ioread8(fw_cfg_reg_data);
  84         ioread8_rep(fw_cfg_reg_data, buf, count);
  85         mutex_unlock(&fw_cfg_dev_lock);
  86 }
  87
  88 /* clean up fw_cfg device i/o */
  89 static void fw_cfg_io_cleanup(void)
  90 {
  91         if (fw_cfg_is_mmio) {
  92                 iounmap(fw_cfg_dev_base);
  93                 release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
  94         } else {
  95                 ioport_unmap(fw_cfg_dev_base);
  96                 release_region(fw_cfg_p_base, fw_cfg_p_size);
  97         }
  98 }
  99
 100 /* arch-specific ctrl & data register offsets are not available in ACPI, DT */
 101 #if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CTRL_DATA_OFF))
 102 # if (defined(CONFIG_ARM) || defined(CONFIG_ARM64))
 103 #  define FW_CFG_CTRL_OFF 0x08
 104 #  define FW_CFG_DATA_OFF 0x00
 105 # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
 106 #  define FW_CFG_CTRL_OFF 0x00
 107 #  define FW_CFG_DATA_OFF 0x02
 108 # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
 109 #  define FW_CFG_CTRL_OFF 0x00
 110 #  define FW_CFG_DATA_OFF 0x01
 111 # else
 112 #  warning "QEMU FW_CFG may not be available on this architecture!"
 113 #  define FW_CFG_CTRL_OFF 0x00
 114 #  define FW_CFG_DATA_OFF 0x01
 115 # endif
 116 #endif
 117
 118 /* initialize fw_cfg device i/o from platform data */
 119 static int fw_cfg_do_platform_probe(struct platform_device *pdev)
 120 {
 121         char sig[FW_CFG_SIG_SIZE];
 122         struct resource *range, *ctrl, *data;
 123
 124         /* acquire i/o range details */
 125         fw_cfg_is_mmio = false;
 126         range = platform_get_resource(pdev, IORESOURCE_IO, 0);
 127         if (!range) {
 128                 fw_cfg_is_mmio = true;
 129                 range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 130                 if (!range)
 131                         return -EINVAL;
 132         }
 133         fw_cfg_p_base = range->start;
 134         fw_cfg_p_size = resource_size(range);
 135
 136         if (fw_cfg_is_mmio) {
 137                 if (!request_mem_region(fw_cfg_p_base,
 138                                         fw_cfg_p_size, "fw_cfg_mem"))
 139                         return -EBUSY;
 140                 fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
 141                 if (!fw_cfg_dev_base) {
 142                         release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
 143                         return -EFAULT;
 144                 }
 145         } else {
 146                 if (!request_region(fw_cfg_p_base,
 147                                     fw_cfg_p_size, "fw_cfg_io"))
 148                         return -EBUSY;
 149                 fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
 150                 if (!fw_cfg_dev_base) {
 151                         release_region(fw_cfg_p_base, fw_cfg_p_size);
 152                         return -EFAULT;
 153                 }
 154         }
 155
 156         /* were custom register offsets provided (e.g. on the command line)? */
 157         ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
 158         data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
 159         if (ctrl && data) {
 160                 fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
 161                 fw_cfg_reg_data = fw_cfg_dev_base + data->start;
 162         } else {
 163                 /* use architecture-specific offsets */
 164                 fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
 165                 fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
 166         }
 167
 168         /* verify fw_cfg device signature */
 169         fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
 170         if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
 171                 fw_cfg_io_cleanup();
 172                 return -ENODEV;
 173         }
 174
 175         return 0;
 176 }
 177
 178 /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
 179 static u32 fw_cfg_rev;
 180
 181 static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
 182 {
 183         return sprintf(buf, "%u\n", fw_cfg_rev);
 184 }
 185
 186 static const struct {
 187         struct attribute attr;
 188         ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
 189 } fw_cfg_rev_attr = {
 190         .attr = { .name = "rev", .mode = S_IRUSR },
 191         .show = fw_cfg_showrev,
 192 };
 193
 194 /* fw_cfg_sysfs_entry type */
 195 struct fw_cfg_sysfs_entry {
 196         struct kobject kobj;
 197         struct fw_cfg_file f;
 198         struct list_head list;
 199 };
 200
 201 /* get fw_cfg_sysfs_entry from kobject member */
 202 static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
 203 {
 204         return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
 205 }
 206
 207 /* fw_cfg_sysfs_attribute type */
 208 struct fw_cfg_sysfs_attribute {
 209         struct attribute attr;
 210         ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
 211 };
 212
 213 /* get fw_cfg_sysfs_attribute from attribute member */
 214 static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
 215 {
 216         return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
 217 }
 218
 219 /* global cache of fw_cfg_sysfs_entry objects */
 220 static LIST_HEAD(fw_cfg_entry_cache);
 221
 222 /* kobjects removed lazily by kernel, mutual exclusion needed */
 223 static DEFINE_SPINLOCK(fw_cfg_cache_lock);
 224
 225 static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
 226 {
 227         spin_lock(&fw_cfg_cache_lock);
 228         list_add_tail(&entry->list, &fw_cfg_entry_cache);
 229         spin_unlock(&fw_cfg_cache_lock);
 230 }
 231
 232 static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
 233 {
 234         spin_lock(&fw_cfg_cache_lock);
 235         list_del(&entry->list);
 236         spin_unlock(&fw_cfg_cache_lock);
 237 }
 238
 239 static void fw_cfg_sysfs_cache_cleanup(void)
 240 {
 241         struct fw_cfg_sysfs_entry *entry, *next;
 242
 243         list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
 244                 /* will end up invoking fw_cfg_sysfs_cache_delist()
 245                  * via each object's release() method (i.e. destructor)
 246                  */
 247                 kobject_put(&entry->kobj);
 248         }
 249 }
 250
 251 /* default_attrs: per-entry attributes and show methods */
 252
 253 #define FW_CFG_SYSFS_ATTR(_attr) \
 254 struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
 255         .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
 256         .show = fw_cfg_sysfs_show_##_attr, \
 257 }
 258
 259 static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
 260 {
 261         return sprintf(buf, "%u\n", e->f.size);
 262 }
 263
 264 static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
 265 {
 266         return sprintf(buf, "%u\n", e->f.select);
 267 }
 268
 269 static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
 270 {
 271         return sprintf(buf, "%s\n", e->f.name);
 272 }
 273
 274 static FW_CFG_SYSFS_ATTR(size);
 275 static FW_CFG_SYSFS_ATTR(key);
 276 static FW_CFG_SYSFS_ATTR(name);
 277
 278 static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
 279         &fw_cfg_sysfs_attr_size.attr,
 280         &fw_cfg_sysfs_attr_key.attr,
 281         &fw_cfg_sysfs_attr_name.attr,
 282         NULL,
 283 };
 284
 285 /* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
 286 static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
 287                                       char *buf)
 288 {
 289         struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
 290         struct fw_cfg_sysfs_attribute *attr = to_attr(a);
 291
 292         return attr->show(entry, buf);
 293 }
 294
 295 static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
 296         .show = fw_cfg_sysfs_attr_show,
 297 };
 298
 299 /* release: destructor, to be called via kobject_put() */
 300 static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
 301 {
 302         struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
 303
 304         fw_cfg_sysfs_cache_delist(entry);
 305         kfree(entry);
 306 }
 307
 308 /* kobj_type: ties together all properties required to register an entry */
 309 static struct kobj_type fw_cfg_sysfs_entry_ktype = {
 310         .default_attrs = fw_cfg_sysfs_entry_attrs,
 311         .sysfs_ops = &fw_cfg_sysfs_attr_ops,
 312         .release = fw_cfg_sysfs_release_entry,
 313 };
 314
 315 /* raw-read method and attribute */
 316 static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
 317                                      struct bin_attribute *bin_attr,
 318                                      char *buf, loff_t pos, size_t count)
 319 {
 320         struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
 321
 322         if (pos > entry->f.size)
 323                 return -EINVAL;
 324
 325         if (count > entry->f.size - pos)
 326                 count = entry->f.size - pos;
 327
 328         fw_cfg_read_blob(entry->f.select, buf, pos, count);
 329         return count;
 330 }
 331
 332 static struct bin_attribute fw_cfg_sysfs_attr_raw = {
 333         .attr = { .name = "raw", .mode = S_IRUSR },
 334         .read = fw_cfg_sysfs_read_raw,
 335 };
 336
 337 /* kobjects representing top-level and by_key folders */
 338 static struct kobject *fw_cfg_top_ko;
 339 static struct kobject *fw_cfg_sel_ko;
 340
 341 /* register an individual fw_cfg file */
 342 static int fw_cfg_register_file(const struct fw_cfg_file *f)
 343 {
 344         int err;
 345         struct fw_cfg_sysfs_entry *entry;
 346
 347         /* allocate new entry */
 348         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 349         if (!entry)
 350                 return -ENOMEM;
 351
 352         /* set file entry information */
 353         memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
 354
 355         /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
 356         err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
 357                                    fw_cfg_sel_ko, "%d", entry->f.select);
 358         if (err)
 359                 goto err_register;
 360
 361         /* add raw binary content access */
 362         err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
 363         if (err)
 364                 goto err_add_raw;
 365
 366         /* success, add entry to global cache */
 367         fw_cfg_sysfs_cache_enlist(entry);
 368         return 0;
 369
 370 err_add_raw:
 371         kobject_del(&entry->kobj);
 372 err_register:
 373         kfree(entry);
 374         return err;
 375 }
 376
 377 /* iterate over all fw_cfg directory entries, registering each one */
 378 static int fw_cfg_register_dir_entries(void)
 379 {
 380         int ret = 0;
 381         u32 count, i;
 382         struct fw_cfg_file *dir;
 383         size_t dir_size;
 384
 385         fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
 386         count = be32_to_cpu(count);
 387         dir_size = count * sizeof(struct fw_cfg_file);
 388
 389         dir = kmalloc(dir_size, GFP_KERNEL);
 390         if (!dir)
 391                 return -ENOMEM;
 392
 393         fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
 394
 395         for (i = 0; i < count; i++) {
 396                 dir[i].size = be32_to_cpu(dir[i].size);
 397                 dir[i].select = be16_to_cpu(dir[i].select);
 398                 ret = fw_cfg_register_file(&dir[i]);
 399                 if (ret)
 400                         break;
 401         }
 402
 403         kfree(dir);
 404         return ret;
 405 }
 406
 407 /* unregister top-level or by_key folder */
 408 static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
 409 {
 410         kobject_del(kobj);
 411         kobject_put(kobj);
 412 }
 413
 414 static int fw_cfg_sysfs_probe(struct platform_device *pdev)
 415 {
 416         int err;
 417
 418         /* NOTE: If we supported multiple fw_cfg devices, we'd first create
 419          * a subdirectory named after e.g. pdev->id, then hang per-device
 420          * by_key subdirectories underneath it. However, only
 421          * one fw_cfg device exist system-wide, so if one was already found
 422          * earlier, we might as well stop here.
 423          */
 424         if (fw_cfg_sel_ko)
 425                 return -EBUSY;
 426
 427         /* create by_key subdirectory of /sys/firmware/qemu_fw_cfg/ */
 428         err = -ENOMEM;
 429         fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
 430         if (!fw_cfg_sel_ko)
 431                 goto err_sel;
 432
 433         /* initialize fw_cfg device i/o from platform data */
 434         err = fw_cfg_do_platform_probe(pdev);
 435         if (err)
 436                 goto err_probe;
 437
 438         /* get revision number, add matching top-level attribute */
 439         fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
 440         fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
 441         err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
 442         if (err)
 443                 goto err_rev;
 444
 445         /* process fw_cfg file directory entry, registering each file */
 446         err = fw_cfg_register_dir_entries();
 447         if (err)
 448                 goto err_dir;
 449
 450         /* success */
 451         pr_debug("fw_cfg: loaded.\n");
 452         return 0;
 453
 454 err_dir:
 455         fw_cfg_sysfs_cache_cleanup();
 456         sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
 457 err_rev:
 458         fw_cfg_io_cleanup();
 459 err_probe:
 460         fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
 461 err_sel:
 462         return err;
 463 }
 464
 465 static int fw_cfg_sysfs_remove(struct platform_device *pdev)
 466 {
 467         pr_debug("fw_cfg: unloading.\n");
 468         fw_cfg_sysfs_cache_cleanup();
 469         fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
 470         fw_cfg_io_cleanup();
 471         return 0;
 472 }
 473
 474 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
 475         { .compatible = "qemu,fw-cfg-mmio", },
 476         {},
 477 };
 478 MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
 479
 480 #ifdef CONFIG_ACPI
 481 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
 482         { "QEMU0002", },
 483         {},
 484 };
 485 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
 486 #endif
 487
 488 static struct platform_driver fw_cfg_sysfs_driver = {
 489         .probe = fw_cfg_sysfs_probe,
 490         .remove = fw_cfg_sysfs_remove,
 491         .driver = {
 492                 .name = "fw_cfg",
 493                 .of_match_table = fw_cfg_sysfs_mmio_match,
 494                 .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
 495         },
 496 };
 497
 498 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
 499
 500 static struct platform_device *fw_cfg_cmdline_dev;
 501
 502 /* this probably belongs in e.g. include/linux/types.h,
 503  * but right now we are the only ones doing it...
 504  */
 505 #ifdef CONFIG_PHYS_ADDR_T_64BIT
 506 #define __PHYS_ADDR_PREFIX "ll"
 507 #else
 508 #define __PHYS_ADDR_PREFIX ""
 509 #endif
 510
 511 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */
 512 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
 513                          ":%" __PHYS_ADDR_PREFIX "i" \
 514                          ":%" __PHYS_ADDR_PREFIX "i%n"
 515
 516 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
 517                          "0x%" __PHYS_ADDR_PREFIX "x"
 518
 519 #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
 520                          ":%" __PHYS_ADDR_PREFIX "u" \
 521                          ":%" __PHYS_ADDR_PREFIX "u"
 522
 523 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
 524 {
 525         struct resource res[3] = {};
 526         char *str;
 527         phys_addr_t base;
 528         resource_size_t size, ctrl_off, data_off;
 529         int processed, consumed = 0;
 530
 531         /* only one fw_cfg device can exist system-wide, so if one
 532          * was processed on the command line already, we might as
 533          * well stop here.
 534          */
 535         if (fw_cfg_cmdline_dev) {
 536                 /* avoid leaking previously registered device */
 537                 platform_device_unregister(fw_cfg_cmdline_dev);
 538                 return -EINVAL;
 539         }
 540
 541         /* consume "<size>" portion of command line argument */
 542         size = memparse(arg, &str);
 543
 544         /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
 545         processed = sscanf(str, PH_ADDR_SCAN_FMT,
 546                            &base, &consumed,
 547                            &ctrl_off, &data_off, &consumed);
 548
 549         /* sscanf() must process precisely 1 or 3 chunks:
 550          * <base> is mandatory, optionally followed by <ctrl_off>
 551          * and <data_off>;
 552          * there must be no extra characters after the last chunk,
 553          * so str[consumed] must be '\0'.
 554          */
 555         if (str[consumed] ||
 556             (processed != 1 && processed != 3))
 557                 return -EINVAL;
 558
 559         res[0].start = base;
 560         res[0].end = base + size - 1;
 561         res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
 562                                                    IORESOURCE_IO;
 563
 564         /* insert register offsets, if provided */
 565         if (processed > 1) {
 566                 res[1].name = "ctrl";
 567                 res[1].start = ctrl_off;
 568                 res[1].flags = IORESOURCE_REG;
 569                 res[2].name = "data";
 570                 res[2].start = data_off;
 571                 res[2].flags = IORESOURCE_REG;
 572         }
 573
 574         /* "processed" happens to nicely match the number of resources
 575          * we need to pass in to this platform device.
 576          */
 577         fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
 578                                         PLATFORM_DEVID_NONE, res, processed);
 579         if (IS_ERR(fw_cfg_cmdline_dev))
 580                 return PTR_ERR(fw_cfg_cmdline_dev);
 581
 582         return 0;
 583 }
 584
 585 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
 586 {
 587         /* stay silent if device was not configured via the command
 588          * line, or if the parameter name (ioport/mmio) doesn't match
 589          * the device setting
 590          */
 591         if (!fw_cfg_cmdline_dev ||
 592             (!strcmp(kp->name, "mmio") ^
 593              (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
 594                 return 0;
 595
 596         switch (fw_cfg_cmdline_dev->num_resources) {
 597         case 1:
 598                 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
 599                                 resource_size(&fw_cfg_cmdline_dev->resource[0]),
 600                                 fw_cfg_cmdline_dev->resource[0].start);
 601         case 3:
 602                 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
 603                                 resource_size(&fw_cfg_cmdline_dev->resource[0]),
 604                                 fw_cfg_cmdline_dev->resource[0].start,
 605                                 fw_cfg_cmdline_dev->resource[1].start,
 606                                 fw_cfg_cmdline_dev->resource[2].start);
 607         }
 608
 609         /* Should never get here */
 610         WARN(1, "Unexpected number of resources: %d\n",
 611                 fw_cfg_cmdline_dev->num_resources);
 612         return 0;
 613 }
 614
 615 static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
 616         .set = fw_cfg_cmdline_set,
 617         .get = fw_cfg_cmdline_get,
 618 };
 619
 620 device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
 621 device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
 622
 623 #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
 624
 625 static int __init fw_cfg_sysfs_init(void)
 626 {
 627         /* create /sys/firmware/qemu_fw_cfg/ top level directory */
 628         fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
 629         if (!fw_cfg_top_ko)
 630                 return -ENOMEM;
 631
 632         return platform_driver_register(&fw_cfg_sysfs_driver);
 633 }
 634
 635 static void __exit fw_cfg_sysfs_exit(void)
 636 {
 637         platform_driver_unregister(&fw_cfg_sysfs_driver);
 638
 639 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
 640         platform_device_unregister(fw_cfg_cmdline_dev);
 641 #endif
 642
 643         /* clean up /sys/firmware/qemu_fw_cfg/ */
 644         fw_cfg_kobj_cleanup(fw_cfg_top_ko);
 645 }
 646
 647 module_init(fw_cfg_sysfs_init);
 648 module_exit(fw_cfg_sysfs_exit);