root/drivers/staging/uwb/whc-rc.c

DEFINITIONS

1. whcrc_cmd
2. whcrc_reset
3. whcrc_enable_events
4. whcrc_event_work
5. whcrc_irq_cb
6. whcrc_setup_rc_umc
7. whcrc_release_rc_umc
8. whcrc_start_rc
9. whcrc_stop_rc
10. whcrc_init
11. whcrc_probe
12. whcrc_remove
13. whcrc_pre_reset
14. whcrc_post_reset
15. whcrc_driver_init
16. whcrc_driver_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Wireless Host Controller: Radio Control Interface (WHCI v0.95[2.3])
   4  * Radio Control command/event transport to the UWB stack
   5  *
   6  * Copyright (C) 2005-2006 Intel Corporation
   7  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   8  *
   9  * Initialize and hook up the Radio Control interface.
  10  *
  11  * For each device probed, creates an 'struct whcrc' which contains
  12  * just the representation of the UWB Radio Controller, and the logic
  13  * for reading notifications and passing them to the UWB Core.
  14  *
  15  * So we initialize all of those, register the UWB Radio Controller
  16  * and setup the notification/event handle to pipe the notifications
  17  * to the UWB management Daemon.
  18  *
  19  * Once uwb_rc_add() is called, the UWB stack takes control, resets
  20  * the radio and readies the device to take commands the UWB
  21  * API/user-space.
  22  *
  23  * Note this driver is just a transport driver; the commands are
  24  * formed at the UWB stack and given to this driver who will deliver
  25  * them to the hw and transfer the replies/notifications back to the
  26  * UWB stack through the UWB daemon (UWBD).
  27  */
  28 #include <linux/init.h>
  29 #include <linux/module.h>
  30 #include <linux/pci.h>
  31 #include <linux/sched.h>
  32 #include <linux/dma-mapping.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/slab.h>
  35 #include <linux/workqueue.h>
  36 #include "uwb.h"
  37 #include "include/whci.h"
  38 #include "include/umc.h"
  39 
  40 #include "uwb-internal.h"
  41 
  42 /**
  43  * Descriptor for an instance of the UWB Radio Control Driver that
  44  * attaches to the URC interface of the WHCI PCI card.
  45  *
  46  * Unless there is a lock specific to the 'data members', all access
  47  * is protected by uwb_rc->mutex.
  48  */
  49 struct whcrc {
  50         struct umc_dev *umc_dev;
  51         struct uwb_rc *uwb_rc;          /* UWB host controller */
  52 
  53         unsigned long area;
  54         void __iomem *rc_base;
  55         size_t rc_len;
  56         spinlock_t irq_lock;
  57 
  58         void *evt_buf, *cmd_buf;
  59         dma_addr_t evt_dma_buf, cmd_dma_buf;
  60         wait_queue_head_t cmd_wq;
  61         struct work_struct event_work;
  62 };
  63 
  64 /**
  65  * Execute an UWB RC command on WHCI/RC
  66  *
  67  * @rc:       Instance of a Radio Controller that is a whcrc
  68  * @cmd:      Buffer containing the RCCB and payload to execute
  69  * @cmd_size: Size of the command buffer.
  70  *
  71  * We copy the command into whcrc->cmd_buf (as it is pretty and
  72  * aligned`and physically contiguous) and then press the right keys in
  73  * the controller's URCCMD register to get it to read it. We might
  74  * have to wait for the cmd_sem to be open to us.
  75  *
  76  * NOTE: rc's mutex has to be locked
  77  */
  78 static int whcrc_cmd(struct uwb_rc *uwb_rc,
  79               const struct uwb_rccb *cmd, size_t cmd_size)
  80 {
  81         int result = 0;
  82         struct whcrc *whcrc = uwb_rc->priv;
  83         struct device *dev = &whcrc->umc_dev->dev;
  84         u32 urccmd;
  85 
  86         if (cmd_size >= 4096)
  87                 return -EINVAL;
  88 
  89         /*
  90          * If the URC is halted, then the hardware has reset itself.
  91          * Attempt to recover by restarting the device and then return
  92          * an error as it's likely that the current command isn't
  93          * valid for a newly started RC.
  94          */
  95         if (le_readl(whcrc->rc_base + URCSTS) & URCSTS_HALTED) {
  96                 dev_err(dev, "requesting reset of halted radio controller\n");
  97                 uwb_rc_reset_all(uwb_rc);
  98                 return -EIO;
  99         }
 100 
 101         result = wait_event_timeout(whcrc->cmd_wq,
 102                 !(le_readl(whcrc->rc_base + URCCMD) & URCCMD_ACTIVE), HZ/2);
 103         if (result == 0) {
 104                 dev_err(dev, "device is not ready to execute commands\n");
 105                 return -ETIMEDOUT;
 106         }
 107 
 108         memmove(whcrc->cmd_buf, cmd, cmd_size);
 109         le_writeq(whcrc->cmd_dma_buf, whcrc->rc_base + URCCMDADDR);
 110 
 111         spin_lock(&whcrc->irq_lock);
 112         urccmd = le_readl(whcrc->rc_base + URCCMD);
 113         urccmd &= ~(URCCMD_EARV | URCCMD_SIZE_MASK);
 114         le_writel(urccmd | URCCMD_ACTIVE | URCCMD_IWR | cmd_size,
 115                   whcrc->rc_base + URCCMD);
 116         spin_unlock(&whcrc->irq_lock);
 117 
 118         return 0;
 119 }
 120 
 121 static int whcrc_reset(struct uwb_rc *rc)
 122 {
 123         struct whcrc *whcrc = rc->priv;
 124 
 125         return umc_controller_reset(whcrc->umc_dev);
 126 }
 127 
 128 /**
 129  * Reset event reception mechanism and tell hw we are ready to get more
 130  *
 131  * We have read all the events in the event buffer, so we are ready to
 132  * reset it to the beginning.
 133  *
 134  * This is only called during initialization or after an event buffer
 135  * has been retired.  This means we can be sure that event processing
 136  * is disabled and it's safe to update the URCEVTADDR register.
 137  *
 138  * There's no need to wait for the event processing to start as the
 139  * URC will not clear URCCMD_ACTIVE until (internal) event buffer
 140  * space is available.
 141  */
 142 static
 143 void whcrc_enable_events(struct whcrc *whcrc)
 144 {
 145         u32 urccmd;
 146 
 147         le_writeq(whcrc->evt_dma_buf, whcrc->rc_base + URCEVTADDR);
 148 
 149         spin_lock(&whcrc->irq_lock);
 150         urccmd = le_readl(whcrc->rc_base + URCCMD) & ~URCCMD_ACTIVE;
 151         le_writel(urccmd | URCCMD_EARV, whcrc->rc_base + URCCMD);
 152         spin_unlock(&whcrc->irq_lock);
 153 }
 154 
 155 static void whcrc_event_work(struct work_struct *work)
 156 {
 157         struct whcrc *whcrc = container_of(work, struct whcrc, event_work);
 158         size_t size;
 159         u64 urcevtaddr;
 160 
 161         urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
 162         size = urcevtaddr & URCEVTADDR_OFFSET_MASK;
 163 
 164         uwb_rc_neh_grok(whcrc->uwb_rc, whcrc->evt_buf, size);
 165         whcrc_enable_events(whcrc);
 166 }
 167 
 168 /**
 169  * Catch interrupts?
 170  *
 171  * We ack inmediately (and expect the hw to do the right thing and
 172  * raise another IRQ if things have changed :)
 173  */
 174 static
 175 irqreturn_t whcrc_irq_cb(int irq, void *_whcrc)
 176 {
 177         struct whcrc *whcrc = _whcrc;
 178         struct device *dev = &whcrc->umc_dev->dev;
 179         u32 urcsts;
 180 
 181         urcsts = le_readl(whcrc->rc_base + URCSTS);
 182         if (!(urcsts & URCSTS_INT_MASK))
 183                 return IRQ_NONE;
 184         le_writel(urcsts & URCSTS_INT_MASK, whcrc->rc_base + URCSTS);
 185 
 186         if (urcsts & URCSTS_HSE) {
 187                 dev_err(dev, "host system error -- hardware halted\n");
 188                 /* FIXME: do something sensible here */
 189                 goto out;
 190         }
 191         if (urcsts & URCSTS_ER)
 192                 schedule_work(&whcrc->event_work);
 193         if (urcsts & URCSTS_RCI)
 194                 wake_up_all(&whcrc->cmd_wq);
 195 out:
 196         return IRQ_HANDLED;
 197 }
 198 
 199 
 200 /**
 201  * Initialize a UMC RC interface: map regions, get (shared) IRQ
 202  */
 203 static
 204 int whcrc_setup_rc_umc(struct whcrc *whcrc)
 205 {
 206         int result = 0;
 207         struct device *dev = &whcrc->umc_dev->dev;
 208         struct umc_dev *umc_dev = whcrc->umc_dev;
 209 
 210         whcrc->area = umc_dev->resource.start;
 211         whcrc->rc_len = resource_size(&umc_dev->resource);
 212         result = -EBUSY;
 213         if (request_mem_region(whcrc->area, whcrc->rc_len, KBUILD_MODNAME) == NULL) {
 214                 dev_err(dev, "can't request URC region (%zu bytes @ 0x%lx): %d\n",
 215                         whcrc->rc_len, whcrc->area, result);
 216                 goto error_request_region;
 217         }
 218 
 219         whcrc->rc_base = ioremap_nocache(whcrc->area, whcrc->rc_len);
 220         if (whcrc->rc_base == NULL) {
 221                 dev_err(dev, "can't ioremap registers (%zu bytes @ 0x%lx): %d\n",
 222                         whcrc->rc_len, whcrc->area, result);
 223                 goto error_ioremap_nocache;
 224         }
 225 
 226         result = request_irq(umc_dev->irq, whcrc_irq_cb, IRQF_SHARED,
 227                              KBUILD_MODNAME, whcrc);
 228         if (result < 0) {
 229                 dev_err(dev, "can't allocate IRQ %d: %d\n",
 230                         umc_dev->irq, result);
 231                 goto error_request_irq;
 232         }
 233 
 234         result = -ENOMEM;
 235         whcrc->cmd_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
 236                                             &whcrc->cmd_dma_buf, GFP_KERNEL);
 237         if (whcrc->cmd_buf == NULL) {
 238                 dev_err(dev, "Can't allocate cmd transfer buffer\n");
 239                 goto error_cmd_buffer;
 240         }
 241 
 242         whcrc->evt_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
 243                                             &whcrc->evt_dma_buf, GFP_KERNEL);
 244         if (whcrc->evt_buf == NULL) {
 245                 dev_err(dev, "Can't allocate evt transfer buffer\n");
 246                 goto error_evt_buffer;
 247         }
 248         return 0;
 249 
 250 error_evt_buffer:
 251         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
 252                           whcrc->cmd_dma_buf);
 253 error_cmd_buffer:
 254         free_irq(umc_dev->irq, whcrc);
 255 error_request_irq:
 256         iounmap(whcrc->rc_base);
 257 error_ioremap_nocache:
 258         release_mem_region(whcrc->area, whcrc->rc_len);
 259 error_request_region:
 260         return result;
 261 }
 262 
 263 
 264 /**
 265  * Release RC's UMC resources
 266  */
 267 static
 268 void whcrc_release_rc_umc(struct whcrc *whcrc)
 269 {
 270         struct umc_dev *umc_dev = whcrc->umc_dev;
 271 
 272         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->evt_buf,
 273                           whcrc->evt_dma_buf);
 274         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
 275                           whcrc->cmd_dma_buf);
 276         free_irq(umc_dev->irq, whcrc);
 277         iounmap(whcrc->rc_base);
 278         release_mem_region(whcrc->area, whcrc->rc_len);
 279 }
 280 
 281 
 282 /**
 283  * whcrc_start_rc - start a WHCI radio controller
 284  * @whcrc: the radio controller to start
 285  *
 286  * Reset the UMC device, start the radio controller, enable events and
 287  * finally enable interrupts.
 288  */
 289 static int whcrc_start_rc(struct uwb_rc *rc)
 290 {
 291         struct whcrc *whcrc = rc->priv;
 292         struct device *dev = &whcrc->umc_dev->dev;
 293 
 294         /* Reset the thing */
 295         le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);
 296         if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,
 297                           5000, "hardware reset") < 0)
 298                 return -EBUSY;
 299 
 300         /* Set the event buffer, start the controller (enable IRQs later) */
 301         le_writel(0, whcrc->rc_base + URCINTR);
 302         le_writel(URCCMD_RS, whcrc->rc_base + URCCMD);
 303         if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,
 304                           5000, "radio controller start") < 0)
 305                 return -ETIMEDOUT;
 306         whcrc_enable_events(whcrc);
 307         le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);
 308         return 0;
 309 }
 310 
 311 
 312 /**
 313  * whcrc_stop_rc - stop a WHCI radio controller
 314  * @whcrc: the radio controller to stop
 315  *
 316  * Disable interrupts and cancel any pending event processing work
 317  * before clearing the Run/Stop bit.
 318  */
 319 static
 320 void whcrc_stop_rc(struct uwb_rc *rc)
 321 {
 322         struct whcrc *whcrc = rc->priv;
 323         struct umc_dev *umc_dev = whcrc->umc_dev;
 324 
 325         le_writel(0, whcrc->rc_base + URCINTR);
 326         cancel_work_sync(&whcrc->event_work);
 327 
 328         le_writel(0, whcrc->rc_base + URCCMD);
 329         whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,
 330                       URCSTS_HALTED, URCSTS_HALTED, 100, "radio controller stop");
 331 }
 332 
 333 static void whcrc_init(struct whcrc *whcrc)
 334 {
 335         spin_lock_init(&whcrc->irq_lock);
 336         init_waitqueue_head(&whcrc->cmd_wq);
 337         INIT_WORK(&whcrc->event_work, whcrc_event_work);
 338 }
 339 
 340 /**
 341  * Initialize the radio controller.
 342  *
 343  * NOTE: we setup whcrc->uwb_rc before calling uwb_rc_add(); in the
 344  *       IRQ handler we use that to determine if the hw is ready to
 345  *       handle events. Looks like a race condition, but it really is
 346  *       not.
 347  */
 348 static
 349 int whcrc_probe(struct umc_dev *umc_dev)
 350 {
 351         int result;
 352         struct uwb_rc *uwb_rc;
 353         struct whcrc *whcrc;
 354         struct device *dev = &umc_dev->dev;
 355 
 356         result = -ENOMEM;
 357         uwb_rc = uwb_rc_alloc();
 358         if (uwb_rc == NULL) {
 359                 dev_err(dev, "unable to allocate RC instance\n");
 360                 goto error_rc_alloc;
 361         }
 362         whcrc = kzalloc(sizeof(*whcrc), GFP_KERNEL);
 363         if (whcrc == NULL) {
 364                 dev_err(dev, "unable to allocate WHC-RC instance\n");
 365                 goto error_alloc;
 366         }
 367         whcrc_init(whcrc);
 368         whcrc->umc_dev = umc_dev;
 369 
 370         result = whcrc_setup_rc_umc(whcrc);
 371         if (result < 0) {
 372                 dev_err(dev, "Can't setup RC UMC interface: %d\n", result);
 373                 goto error_setup_rc_umc;
 374         }
 375         whcrc->uwb_rc = uwb_rc;
 376 
 377         uwb_rc->owner = THIS_MODULE;
 378         uwb_rc->cmd   = whcrc_cmd;
 379         uwb_rc->reset = whcrc_reset;
 380         uwb_rc->start = whcrc_start_rc;
 381         uwb_rc->stop  = whcrc_stop_rc;
 382 
 383         result = uwb_rc_add(uwb_rc, dev, whcrc);
 384         if (result < 0)
 385                 goto error_rc_add;
 386         umc_set_drvdata(umc_dev, whcrc);
 387         return 0;
 388 
 389 error_rc_add:
 390         whcrc_release_rc_umc(whcrc);
 391 error_setup_rc_umc:
 392         kfree(whcrc);
 393 error_alloc:
 394         uwb_rc_put(uwb_rc);
 395 error_rc_alloc:
 396         return result;
 397 }
 398 
 399 /**
 400  * Clean up the radio control resources
 401  *
 402  * When we up the command semaphore, everybody possibly held trying to
 403  * execute a command should be granted entry and then they'll see the
 404  * host is quiescing and up it (so it will chain to the next waiter).
 405  * This should not happen (in any case), as we can only remove when
 406  * there are no handles open...
 407  */
 408 static void whcrc_remove(struct umc_dev *umc_dev)
 409 {
 410         struct whcrc *whcrc = umc_get_drvdata(umc_dev);
 411         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
 412 
 413         umc_set_drvdata(umc_dev, NULL);
 414         uwb_rc_rm(uwb_rc);
 415         whcrc_release_rc_umc(whcrc);
 416         kfree(whcrc);
 417         uwb_rc_put(uwb_rc);
 418 }
 419 
 420 static int whcrc_pre_reset(struct umc_dev *umc)
 421 {
 422         struct whcrc *whcrc = umc_get_drvdata(umc);
 423         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
 424 
 425         uwb_rc_pre_reset(uwb_rc);
 426         return 0;
 427 }
 428 
 429 static int whcrc_post_reset(struct umc_dev *umc)
 430 {
 431         struct whcrc *whcrc = umc_get_drvdata(umc);
 432         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
 433 
 434         return uwb_rc_post_reset(uwb_rc);
 435 }
 436 
 437 /* PCI device ID's that we handle [so it gets loaded] */
 438 static struct pci_device_id __used whcrc_id_table[] = {
 439         { PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
 440         { /* empty last entry */ }
 441 };
 442 MODULE_DEVICE_TABLE(pci, whcrc_id_table);
 443 
 444 static struct umc_driver whcrc_driver = {
 445         .name       = "whc-rc",
 446         .cap_id     = UMC_CAP_ID_WHCI_RC,
 447         .probe      = whcrc_probe,
 448         .remove     = whcrc_remove,
 449         .pre_reset  = whcrc_pre_reset,
 450         .post_reset = whcrc_post_reset,
 451 };
 452 
 453 static int __init whcrc_driver_init(void)
 454 {
 455         return umc_driver_register(&whcrc_driver);
 456 }
 457 module_init(whcrc_driver_init);
 458 
 459 static void __exit whcrc_driver_exit(void)
 460 {
 461         umc_driver_unregister(&whcrc_driver);
 462 }
 463 module_exit(whcrc_driver_exit);
 464 
 465 MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
 466 MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver");
 467 MODULE_LICENSE("GPL");