drivers/pci/hotplug/acpiphp_ibm.c

   1 /*
   2  * ACPI PCI Hot Plug IBM Extension
   3  *
   4  * Copyright (C) 2004 Vernon Mauery <vernux@us.ibm.com>
   5  * Copyright (C) 2004 IBM Corp.
   6  *
   7  * All rights reserved.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or (at
  12  * your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  17  * NON INFRINGEMENT.  See the GNU General Public License for more
  18  * details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23  *
  24  * Send feedback to <vernux@us.ibm.com>
  25  *
  26  */
  27
  28 #define pr_fmt(fmt) "acpiphp_ibm: " fmt
  29
  30 #include <linux/init.h>
  31 #include <linux/slab.h>
  32 #include <linux/module.h>
  33 #include <linux/kernel.h>
  34 #include <linux/sysfs.h>
  35 #include <linux/kobject.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/pci.h>
  38 #include <asm/uaccess.h>
  39
  40 #include "acpiphp.h"
  41 #include "../pci.h"
  42
  43 #define DRIVER_VERSION  "1.0.1"
  44 #define DRIVER_AUTHOR   "Irene Zubarev <zubarev@us.ibm.com>, Vernon Mauery <vernux@us.ibm.com>"
  45 #define DRIVER_DESC     "ACPI Hot Plug PCI Controller Driver IBM extension"
  46
  47
  48 MODULE_AUTHOR(DRIVER_AUTHOR);
  49 MODULE_DESCRIPTION(DRIVER_DESC);
  50 MODULE_LICENSE("GPL");
  51 MODULE_VERSION(DRIVER_VERSION);
  52
  53 #define FOUND_APCI 0x61504349
  54 /* these are the names for the IBM ACPI pseudo-device */
  55 #define IBM_HARDWARE_ID1 "IBM37D0"
  56 #define IBM_HARDWARE_ID2 "IBM37D4"
  57
  58 #define hpslot_to_sun(A) (((struct slot *)((A)->private))->sun)
  59
  60 /* union apci_descriptor - allows access to the
  61  * various device descriptors that are embedded in the
  62  * aPCI table
  63  */
  64 union apci_descriptor {
  65         struct {
  66                 char sig[4];
  67                 u8   len;
  68         } header;
  69         struct {
  70                 u8  type;
  71                 u8  len;
  72                 u16 slot_id;
  73                 u8  bus_id;
  74                 u8  dev_num;
  75                 u8  slot_num;
  76                 u8  slot_attr[2];
  77                 u8  attn;
  78                 u8  status[2];
  79                 u8  sun;
  80                 u8  res[3];
  81         } slot;
  82         struct {
  83                 u8 type;
  84                 u8 len;
  85         } generic;
  86 };
  87
  88 /* struct notification - keeps info about the device
  89  * that cause the ACPI notification event
  90  */
  91 struct notification {
  92         struct acpi_device *device;
  93         u8                  event;
  94 };
  95
  96 static int ibm_set_attention_status(struct hotplug_slot *slot, u8 status);
  97 static int ibm_get_attention_status(struct hotplug_slot *slot, u8 *status);
  98 static void ibm_handle_events(acpi_handle handle, u32 event, void *context);
  99 static int ibm_get_table_from_acpi(char **bufp);
 100 static ssize_t ibm_read_apci_table(struct file *filp, struct kobject *kobj,
 101                                    struct bin_attribute *bin_attr,
 102                                    char *buffer, loff_t pos, size_t size);
 103 static acpi_status __init ibm_find_acpi_device(acpi_handle handle,
 104                 u32 lvl, void *context, void **rv);
 105 static int __init ibm_acpiphp_init(void);
 106 static void __exit ibm_acpiphp_exit(void);
 107
 108 static acpi_handle ibm_acpi_handle;
 109 static struct notification ibm_note;
 110 static struct bin_attribute ibm_apci_table_attr = {
 111             .attr = {
 112                     .name = "apci_table",
 113                     .mode = S_IRUGO,
 114             },
 115             .read = ibm_read_apci_table,
 116             .write = NULL,
 117 };
 118 static struct acpiphp_attention_info ibm_attention_info =
 119 {
 120         .set_attn = ibm_set_attention_status,
 121         .get_attn = ibm_get_attention_status,
 122         .owner = THIS_MODULE,
 123 };
 124
 125 /**
 126  * ibm_slot_from_id - workaround for bad ibm hardware
 127  * @id: the slot number that linux refers to the slot by
 128  *
 129  * Description: This method returns the aCPI slot descriptor
 130  * corresponding to the Linux slot number.  This descriptor
 131  * has info about the aPCI slot id and attention status.
 132  * This descriptor must be freed using kfree when done.
 133  */
 134 static union apci_descriptor *ibm_slot_from_id(int id)
 135 {
 136         int ind = 0, size;
 137         union apci_descriptor *ret = NULL, *des;
 138         char *table;
 139
 140         size = ibm_get_table_from_acpi(&table);
 141         des = (union apci_descriptor *)table;
 142         if (memcmp(des->header.sig, "aPCI", 4) != 0)
 143                 goto ibm_slot_done;
 144
 145         des = (union apci_descriptor *)&table[ind += des->header.len];
 146         while (ind < size && (des->generic.type != 0x82 ||
 147                         des->slot.slot_num != id)) {
 148                 des = (union apci_descriptor *)&table[ind += des->generic.len];
 149         }
 150
 151         if (ind < size && des->slot.slot_num == id)
 152                 ret = des;
 153
 154 ibm_slot_done:
 155         if (ret) {
 156                 ret = kmalloc(sizeof(union apci_descriptor), GFP_KERNEL);
 157                 if (ret)
 158                         memcpy(ret, des, sizeof(union apci_descriptor));
 159         }
 160         kfree(table);
 161         return ret;
 162 }
 163
 164 /**
 165  * ibm_set_attention_status - callback method to set the attention LED
 166  * @slot: the hotplug_slot to work with
 167  * @status: what to set the LED to (0 or 1)
 168  *
 169  * Description: This method is registered with the acpiphp module as a
 170  * callback to do the device specific task of setting the LED status.
 171  */
 172 static int ibm_set_attention_status(struct hotplug_slot *slot, u8 status)
 173 {
 174         union acpi_object args[2];
 175         struct acpi_object_list params = { .pointer = args, .count = 2 };
 176         acpi_status stat;
 177         unsigned long long rc;
 178         union apci_descriptor *ibm_slot;
 179         int id = hpslot_to_sun(slot);
 180
 181         ibm_slot = ibm_slot_from_id(id);
 182         if (!ibm_slot) {
 183                 pr_err("APLS null ACPI descriptor for slot %d\n", id);
 184                 return -ENODEV;
 185         }
 186
 187         pr_debug("%s: set slot %d (%d) attention status to %d\n", __func__,
 188                         ibm_slot->slot.slot_num, ibm_slot->slot.slot_id,
 189                         (status ? 1 : 0));
 190
 191         args[0].type = ACPI_TYPE_INTEGER;
 192         args[0].integer.value = ibm_slot->slot.slot_id;
 193         args[1].type = ACPI_TYPE_INTEGER;
 194         args[1].integer.value = (status) ? 1 : 0;
 195
 196         kfree(ibm_slot);
 197
 198         stat = acpi_evaluate_integer(ibm_acpi_handle, "APLS", &params, &rc);
 199         if (ACPI_FAILURE(stat)) {
 200                 pr_err("APLS evaluation failed:  0x%08x\n", stat);
 201                 return -ENODEV;
 202         } else if (!rc) {
 203                 pr_err("APLS method failed:  0x%08llx\n", rc);
 204                 return -ERANGE;
 205         }
 206         return 0;
 207 }
 208
 209 /**
 210  * ibm_get_attention_status - callback method to get attention LED status
 211  * @slot: the hotplug_slot to work with
 212  * @status: returns what the LED is set to (0 or 1)
 213  *
 214  * Description: This method is registered with the acpiphp module as a
 215  * callback to do the device specific task of getting the LED status.
 216  *
 217  * Because there is no direct method of getting the LED status directly
 218  * from an ACPI call, we read the aPCI table and parse out our
 219  * slot descriptor to read the status from that.
 220  */
 221 static int ibm_get_attention_status(struct hotplug_slot *slot, u8 *status)
 222 {
 223         union apci_descriptor *ibm_slot;
 224         int id = hpslot_to_sun(slot);
 225
 226         ibm_slot = ibm_slot_from_id(id);
 227         if (!ibm_slot) {
 228                 pr_err("APLS null ACPI descriptor for slot %d\n", id);
 229                 return -ENODEV;
 230         }
 231
 232         if (ibm_slot->slot.attn & 0xa0 || ibm_slot->slot.status[1] & 0x08)
 233                 *status = 1;
 234         else
 235                 *status = 0;
 236
 237         pr_debug("%s: get slot %d (%d) attention status is %d\n", __func__,
 238                         ibm_slot->slot.slot_num, ibm_slot->slot.slot_id,
 239                         *status);
 240
 241         kfree(ibm_slot);
 242         return 0;
 243 }
 244
 245 /**
 246  * ibm_handle_events - listens for ACPI events for the IBM37D0 device
 247  * @handle: an ACPI handle to the device that caused the event
 248  * @event: the event info (device specific)
 249  * @context: passed context (our notification struct)
 250  *
 251  * Description: This method is registered as a callback with the ACPI
 252  * subsystem it is called when this device has an event to notify the OS of.
 253  *
 254  * The events actually come from the device as two events that get
 255  * synthesized into one event with data by this function.  The event
 256  * ID comes first and then the slot number that caused it.  We report
 257  * this as one event to the OS.
 258  *
 259  * From section 5.6.2.2 of the ACPI 2.0 spec, I understand that the OSPM will
 260  * only re-enable the interrupt that causes this event AFTER this method
 261  * has returned, thereby enforcing serial access for the notification struct.
 262  */
 263 static void ibm_handle_events(acpi_handle handle, u32 event, void *context)
 264 {
 265         u8 detail = event & 0x0f;
 266         u8 subevent = event & 0xf0;
 267         struct notification *note = context;
 268
 269         pr_debug("%s: Received notification %02x\n", __func__, event);
 270
 271         if (subevent == 0x80) {
 272                 pr_debug("%s: generating bus event\n", __func__);
 273                 acpi_bus_generate_netlink_event(note->device->pnp.device_class,
 274                                                   dev_name(&note->device->dev),
 275                                                   note->event, detail);
 276         } else
 277                 note->event = event;
 278 }
 279
 280 /**
 281  * ibm_get_table_from_acpi - reads the APLS buffer from ACPI
 282  * @bufp: address to pointer to allocate for the table
 283  *
 284  * Description: This method reads the APLS buffer in from ACPI and
 285  * stores the "stripped" table into a single buffer
 286  * it allocates and passes the address back in bufp.
 287  *
 288  * If NULL is passed in as buffer, this method only calculates
 289  * the size of the table and returns that without filling
 290  * in the buffer.
 291  *
 292  * Returns < 0 on error or the size of the table on success.
 293  */
 294 static int ibm_get_table_from_acpi(char **bufp)
 295 {
 296         union acpi_object *package;
 297         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 298         acpi_status status;
 299         char *lbuf = NULL;
 300         int i, size = -EIO;
 301
 302         status = acpi_evaluate_object(ibm_acpi_handle, "APCI", NULL, &buffer);
 303         if (ACPI_FAILURE(status)) {
 304                 pr_err("%s:  APCI evaluation failed\n", __func__);
 305                 return -ENODEV;
 306         }
 307
 308         package = (union acpi_object *) buffer.pointer;
 309         if (!(package) ||
 310                         (package->type != ACPI_TYPE_PACKAGE) ||
 311                         !(package->package.elements)) {
 312                 pr_err("%s:  Invalid APCI object\n", __func__);
 313                 goto read_table_done;
 314         }
 315
 316         for (size = 0, i = 0; i < package->package.count; i++) {
 317                 if (package->package.elements[i].type != ACPI_TYPE_BUFFER) {
 318                         pr_err("%s:  Invalid APCI element %d\n", __func__, i);
 319                         goto read_table_done;
 320                 }
 321                 size += package->package.elements[i].buffer.length;
 322         }
 323
 324         if (bufp == NULL)
 325                 goto read_table_done;
 326
 327         lbuf = kzalloc(size, GFP_KERNEL);
 328         pr_debug("%s: element count: %i, ASL table size: %i, &table = 0x%p\n",
 329                         __func__, package->package.count, size, lbuf);
 330
 331         if (lbuf) {
 332                 *bufp = lbuf;
 333         } else {
 334                 size = -ENOMEM;
 335                 goto read_table_done;
 336         }
 337
 338         size = 0;
 339         for (i = 0; i < package->package.count; i++) {
 340                 memcpy(&lbuf[size],
 341                                 package->package.elements[i].buffer.pointer,
 342                                 package->package.elements[i].buffer.length);
 343                 size += package->package.elements[i].buffer.length;
 344         }
 345
 346 read_table_done:
 347         kfree(buffer.pointer);
 348         return size;
 349 }
 350
 351 /**
 352  * ibm_read_apci_table - callback for the sysfs apci_table file
 353  * @filp: the open sysfs file
 354  * @kobj: the kobject this binary attribute is a part of
 355  * @bin_attr: struct bin_attribute for this file
 356  * @buffer: the kernel space buffer to fill
 357  * @pos: the offset into the file
 358  * @size: the number of bytes requested
 359  *
 360  * Description: Gets registered with sysfs as the reader callback
 361  * to be executed when /sys/bus/pci/slots/apci_table gets read.
 362  *
 363  * Since we don't get notified on open and close for this file,
 364  * things get really tricky here...
 365  * our solution is to only allow reading the table in all at once.
 366  */
 367 static ssize_t ibm_read_apci_table(struct file *filp, struct kobject *kobj,
 368                                    struct bin_attribute *bin_attr,
 369                                    char *buffer, loff_t pos, size_t size)
 370 {
 371         int bytes_read = -EINVAL;
 372         char *table = NULL;
 373
 374         pr_debug("%s: pos = %d, size = %zd\n", __func__, (int)pos, size);
 375
 376         if (pos == 0) {
 377                 bytes_read = ibm_get_table_from_acpi(&table);
 378                 if (bytes_read > 0 && bytes_read <= size)
 379                         memcpy(buffer, table, bytes_read);
 380                 kfree(table);
 381         }
 382         return bytes_read;
 383 }
 384
 385 /**
 386  * ibm_find_acpi_device - callback to find our ACPI device
 387  * @handle: the ACPI handle of the device we are inspecting
 388  * @lvl: depth into the namespace tree
 389  * @context: a pointer to our handle to fill when we find the device
 390  * @rv: a return value to fill if desired
 391  *
 392  * Description: Used as a callback when calling acpi_walk_namespace
 393  * to find our device.  When this method returns non-zero
 394  * acpi_walk_namespace quits its search and returns our value.
 395  */
 396 static acpi_status __init ibm_find_acpi_device(acpi_handle handle,
 397                 u32 lvl, void *context, void **rv)
 398 {
 399         acpi_handle *phandle = (acpi_handle *)context;
 400         acpi_status status;
 401         struct acpi_device_info *info;
 402         int retval = 0;
 403
 404         status = acpi_get_object_info(handle, &info);
 405         if (ACPI_FAILURE(status)) {
 406                 pr_err("%s:  Failed to get device information status=0x%x\n",
 407                         __func__, status);
 408                 return retval;
 409         }
 410
 411         if (info->current_status && (info->valid & ACPI_VALID_HID) &&
 412                         (!strcmp(info->hardware_id.string, IBM_HARDWARE_ID1) ||
 413                          !strcmp(info->hardware_id.string, IBM_HARDWARE_ID2))) {
 414                 pr_debug("found hardware: %s, handle: %p\n",
 415                         info->hardware_id.string, handle);
 416                 *phandle = handle;
 417                 /* returning non-zero causes the search to stop
 418                  * and returns this value to the caller of
 419                  * acpi_walk_namespace, but it also causes some warnings
 420                  * in the acpi debug code to print...
 421                  */
 422                 retval = FOUND_APCI;
 423         }
 424         kfree(info);
 425         return retval;
 426 }
 427
 428 static int __init ibm_acpiphp_init(void)
 429 {
 430         int retval = 0;
 431         acpi_status status;
 432         struct acpi_device *device;
 433         struct kobject *sysdir = &pci_slots_kset->kobj;
 434
 435         pr_debug("%s\n", __func__);
 436
 437         if (acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 438                         ACPI_UINT32_MAX, ibm_find_acpi_device, NULL,
 439                         &ibm_acpi_handle, NULL) != FOUND_APCI) {
 440                 pr_err("%s: acpi_walk_namespace failed\n", __func__);
 441                 retval = -ENODEV;
 442                 goto init_return;
 443         }
 444         pr_debug("%s: found IBM aPCI device\n", __func__);
 445         if (acpi_bus_get_device(ibm_acpi_handle, &device)) {
 446                 pr_err("%s: acpi_bus_get_device failed\n", __func__);
 447                 retval = -ENODEV;
 448                 goto init_return;
 449         }
 450         if (acpiphp_register_attention(&ibm_attention_info)) {
 451                 retval = -ENODEV;
 452                 goto init_return;
 453         }
 454
 455         ibm_note.device = device;
 456         status = acpi_install_notify_handler(ibm_acpi_handle,
 457                         ACPI_DEVICE_NOTIFY, ibm_handle_events,
 458                         &ibm_note);
 459         if (ACPI_FAILURE(status)) {
 460                 pr_err("%s: Failed to register notification handler\n",
 461                                 __func__);
 462                 retval = -EBUSY;
 463                 goto init_cleanup;
 464         }
 465
 466         ibm_apci_table_attr.size = ibm_get_table_from_acpi(NULL);
 467         retval = sysfs_create_bin_file(sysdir, &ibm_apci_table_attr);
 468
 469         return retval;
 470
 471 init_cleanup:
 472         acpiphp_unregister_attention(&ibm_attention_info);
 473 init_return:
 474         return retval;
 475 }
 476
 477 static void __exit ibm_acpiphp_exit(void)
 478 {
 479         acpi_status status;
 480         struct kobject *sysdir = &pci_slots_kset->kobj;
 481
 482         pr_debug("%s\n", __func__);
 483
 484         if (acpiphp_unregister_attention(&ibm_attention_info))
 485                 pr_err("%s: attention info deregistration failed", __func__);
 486
 487         status = acpi_remove_notify_handler(
 488                            ibm_acpi_handle,
 489                            ACPI_DEVICE_NOTIFY,
 490                            ibm_handle_events);
 491         if (ACPI_FAILURE(status))
 492                 pr_err("%s: Notification handler removal failed\n", __func__);
 493         /* remove the /sys entries */
 494         sysfs_remove_bin_file(sysdir, &ibm_apci_table_attr);
 495 }
 496
 497 module_init(ibm_acpiphp_init);
 498 module_exit(ibm_acpiphp_exit);