/*
   * Wireless Host Controller: Radio Control Interface (WHCI v0.95[2.3])
   * Radio Control command/event transport to the UWB stack
   *
   * Copyright (C) 2005-2006 Intel Corporation
   * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
   * 02110-1301, USA.
   *
   *
   * Initialize and hook up the Radio Control interface.
   *
   * For each device probed, creates an 'struct whcrc' which contains
   * just the representation of the UWB Radio Controller, and the logic
   * for reading notifications and passing them to the UWB Core.
   *
   * So we initialize all of those, register the UWB Radio Controller
   * and setup the notification/event handle to pipe the notifications
   * to the UWB management Daemon.
   *
   * Once uwb_rc_add() is called, the UWB stack takes control, resets
   * the radio and readies the device to take commands the UWB
   * API/user-space.
   *
   * Note this driver is just a transport driver; the commands are
   * formed at the UWB stack and given to this driver who will deliver
   * them to the hw and transfer the replies/notifications back to the
   * UWB stack through the UWB daemon (UWBD).
   */

  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/pci.h>

  #include <linux/sched.h>

  #include <linux/dma-mapping.h>
  #include <linux/interrupt.h>

  #include <linux/slab.h>

  #include <linux/workqueue.h>
  #include <linux/uwb.h>
  #include <linux/uwb/whci.h>
  #include <linux/uwb/umc.h>

  #include "uwb-internal.h"

  
  /**
   * Descriptor for an instance of the UWB Radio Control Driver that
   * attaches to the URC interface of the WHCI PCI card.
   *
   * Unless there is a lock specific to the 'data members', all access
   * is protected by uwb_rc->mutex.
   */
  struct whcrc {
  	struct umc_dev *umc_dev;
  	struct uwb_rc *uwb_rc;		/* UWB host controller */
  
  	unsigned long area;
  	void __iomem *rc_base;
  	size_t rc_len;
  	spinlock_t irq_lock;
  
  	void *evt_buf, *cmd_buf;
  	dma_addr_t evt_dma_buf, cmd_dma_buf;
  	wait_queue_head_t cmd_wq;
  	struct work_struct event_work;
  };
  
  /**
   * Execute an UWB RC command on WHCI/RC
   *
   * @rc:       Instance of a Radio Controller that is a whcrc
   * @cmd:      Buffer containing the RCCB and payload to execute
   * @cmd_size: Size of the command buffer.
   *
   * We copy the command into whcrc->cmd_buf (as it is pretty and
   * aligned`and physically contiguous) and then press the right keys in
   * the controller's URCCMD register to get it to read it. We might
   * have to wait for the cmd_sem to be open to us.
   *
   * NOTE: rc's mutex has to be locked
   */
  static int whcrc_cmd(struct uwb_rc *uwb_rc,
  	      const struct uwb_rccb *cmd, size_t cmd_size)
  {
  	int result = 0;
  	struct whcrc *whcrc = uwb_rc->priv;
  	struct device *dev = &whcrc->umc_dev->dev;
  	u32 urccmd;

  	if (cmd_size >= 4096)
  		return -EINVAL;

  
  	/*
  	 * If the URC is halted, then the hardware has reset itself.
  	 * Attempt to recover by restarting the device and then return
  	 * an error as it's likely that the current command isn't
  	 * valid for a newly started RC.
  	 */
  	if (le_readl(whcrc->rc_base + URCSTS) & URCSTS_HALTED) {
  		dev_err(dev, "requesting reset of halted radio controller
  ");
  		uwb_rc_reset_all(uwb_rc);

  		return -EIO;

  	}
  
  	result = wait_event_timeout(whcrc->cmd_wq,
  		!(le_readl(whcrc->rc_base + URCCMD) & URCCMD_ACTIVE), HZ/2);
  	if (result == 0) {
  		dev_err(dev, "device is not ready to execute commands
  ");

  		return -ETIMEDOUT;

  	}
  
  	memmove(whcrc->cmd_buf, cmd, cmd_size);
  	le_writeq(whcrc->cmd_dma_buf, whcrc->rc_base + URCCMDADDR);
  
  	spin_lock(&whcrc->irq_lock);
  	urccmd = le_readl(whcrc->rc_base + URCCMD);
  	urccmd &= ~(URCCMD_EARV | URCCMD_SIZE_MASK);
  	le_writel(urccmd | URCCMD_ACTIVE | URCCMD_IWR | cmd_size,
  		  whcrc->rc_base + URCCMD);
  	spin_unlock(&whcrc->irq_lock);

  	return 0;

  }
  
  static int whcrc_reset(struct uwb_rc *rc)
  {
  	struct whcrc *whcrc = rc->priv;
  
  	return umc_controller_reset(whcrc->umc_dev);
  }
  
  /**
   * Reset event reception mechanism and tell hw we are ready to get more
   *
   * We have read all the events in the event buffer, so we are ready to
   * reset it to the beginning.
   *
   * This is only called during initialization or after an event buffer
   * has been retired.  This means we can be sure that event processing
   * is disabled and it's safe to update the URCEVTADDR register.
   *
   * There's no need to wait for the event processing to start as the
   * URC will not clear URCCMD_ACTIVE until (internal) event buffer
   * space is available.
   */
  static
  void whcrc_enable_events(struct whcrc *whcrc)
  {

  	u32 urccmd;

  	le_writeq(whcrc->evt_dma_buf, whcrc->rc_base + URCEVTADDR);
  
  	spin_lock(&whcrc->irq_lock);
  	urccmd = le_readl(whcrc->rc_base + URCCMD) & ~URCCMD_ACTIVE;
  	le_writel(urccmd | URCCMD_EARV, whcrc->rc_base + URCCMD);
  	spin_unlock(&whcrc->irq_lock);

  }
  
  static void whcrc_event_work(struct work_struct *work)
  {
  	struct whcrc *whcrc = container_of(work, struct whcrc, event_work);

  	size_t size;
  	u64 urcevtaddr;
  
  	urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
  	size = urcevtaddr & URCEVTADDR_OFFSET_MASK;

  	uwb_rc_neh_grok(whcrc->uwb_rc, whcrc->evt_buf, size);
  	whcrc_enable_events(whcrc);
  }
  
  /**
   * Catch interrupts?
   *
   * We ack inmediately (and expect the hw to do the right thing and
   * raise another IRQ if things have changed :)
   */
  static
  irqreturn_t whcrc_irq_cb(int irq, void *_whcrc)
  {
  	struct whcrc *whcrc = _whcrc;
  	struct device *dev = &whcrc->umc_dev->dev;
  	u32 urcsts;

  	urcsts = le_readl(whcrc->rc_base + URCSTS);
  	if (!(urcsts & URCSTS_INT_MASK))
  		return IRQ_NONE;
  	le_writel(urcsts & URCSTS_INT_MASK, whcrc->rc_base + URCSTS);

  	if (urcsts & URCSTS_HSE) {
  		dev_err(dev, "host system error -- hardware halted
  ");
  		/* FIXME: do something sensible here */
  		goto out;
  	}

  	if (urcsts & URCSTS_ER)

  		schedule_work(&whcrc->event_work);

  	if (urcsts & URCSTS_RCI)

  		wake_up_all(&whcrc->cmd_wq);

  out:
  	return IRQ_HANDLED;
  }
  
  
  /**
   * Initialize a UMC RC interface: map regions, get (shared) IRQ
   */
  static
  int whcrc_setup_rc_umc(struct whcrc *whcrc)
  {
  	int result = 0;
  	struct device *dev = &whcrc->umc_dev->dev;
  	struct umc_dev *umc_dev = whcrc->umc_dev;
  
  	whcrc->area = umc_dev->resource.start;

  	whcrc->rc_len = resource_size(&umc_dev->resource);

  	result = -EBUSY;

  	if (request_mem_region(whcrc->area, whcrc->rc_len, KBUILD_MODNAME) == NULL) {

  		dev_err(dev, "can't request URC region (%zu bytes @ 0x%lx): %d
  ",
  			whcrc->rc_len, whcrc->area, result);
  		goto error_request_region;
  	}
  
  	whcrc->rc_base = ioremap_nocache(whcrc->area, whcrc->rc_len);
  	if (whcrc->rc_base == NULL) {
  		dev_err(dev, "can't ioremap registers (%zu bytes @ 0x%lx): %d
  ",
  			whcrc->rc_len, whcrc->area, result);
  		goto error_ioremap_nocache;
  	}
  
  	result = request_irq(umc_dev->irq, whcrc_irq_cb, IRQF_SHARED,
  			     KBUILD_MODNAME, whcrc);
  	if (result < 0) {
  		dev_err(dev, "can't allocate IRQ %d: %d
  ",
  			umc_dev->irq, result);
  		goto error_request_irq;
  	}
  
  	result = -ENOMEM;
  	whcrc->cmd_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
  					    &whcrc->cmd_dma_buf, GFP_KERNEL);
  	if (whcrc->cmd_buf == NULL) {
  		dev_err(dev, "Can't allocate cmd transfer buffer
  ");
  		goto error_cmd_buffer;
  	}
  
  	whcrc->evt_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
  					    &whcrc->evt_dma_buf, GFP_KERNEL);
  	if (whcrc->evt_buf == NULL) {
  		dev_err(dev, "Can't allocate evt transfer buffer
  ");
  		goto error_evt_buffer;
  	}

  	return 0;
  
  error_evt_buffer:
  	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
  			  whcrc->cmd_dma_buf);
  error_cmd_buffer:
  	free_irq(umc_dev->irq, whcrc);
  error_request_irq:
  	iounmap(whcrc->rc_base);
  error_ioremap_nocache:
  	release_mem_region(whcrc->area, whcrc->rc_len);
  error_request_region:
  	return result;
  }
  
  
  /**
   * Release RC's UMC resources
   */
  static
  void whcrc_release_rc_umc(struct whcrc *whcrc)
  {
  	struct umc_dev *umc_dev = whcrc->umc_dev;
  
  	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->evt_buf,
  			  whcrc->evt_dma_buf);
  	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
  			  whcrc->cmd_dma_buf);
  	free_irq(umc_dev->irq, whcrc);
  	iounmap(whcrc->rc_base);
  	release_mem_region(whcrc->area, whcrc->rc_len);
  }
  
  
  /**
   * whcrc_start_rc - start a WHCI radio controller
   * @whcrc: the radio controller to start
   *
   * Reset the UMC device, start the radio controller, enable events and
   * finally enable interrupts.
   */
  static int whcrc_start_rc(struct uwb_rc *rc)
  {
  	struct whcrc *whcrc = rc->priv;

  	struct device *dev = &whcrc->umc_dev->dev;

  
  	/* Reset the thing */
  	le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);

  	if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,

  			  5000, "hardware reset") < 0)
  		return -EBUSY;

  
  	/* Set the event buffer, start the controller (enable IRQs later) */
  	le_writel(0, whcrc->rc_base + URCINTR);
  	le_writel(URCCMD_RS, whcrc->rc_base + URCCMD);

  	if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,

  			  5000, "radio controller start") < 0)
  		return -ETIMEDOUT;

  	whcrc_enable_events(whcrc);

  	le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);

  	return 0;

  }
  
  
  /**
   * whcrc_stop_rc - stop a WHCI radio controller
   * @whcrc: the radio controller to stop
   *
   * Disable interrupts and cancel any pending event processing work
   * before clearing the Run/Stop bit.
   */
  static
  void whcrc_stop_rc(struct uwb_rc *rc)
  {
  	struct whcrc *whcrc = rc->priv;
  	struct umc_dev *umc_dev = whcrc->umc_dev;
  
  	le_writel(0, whcrc->rc_base + URCINTR);
  	cancel_work_sync(&whcrc->event_work);
  
  	le_writel(0, whcrc->rc_base + URCCMD);
  	whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,

  		      URCSTS_HALTED, URCSTS_HALTED, 100, "radio controller stop");

  }
  
  static void whcrc_init(struct whcrc *whcrc)
  {
  	spin_lock_init(&whcrc->irq_lock);
  	init_waitqueue_head(&whcrc->cmd_wq);
  	INIT_WORK(&whcrc->event_work, whcrc_event_work);
  }
  
  /**
   * Initialize the radio controller.
   *
   * NOTE: we setup whcrc->uwb_rc before calling uwb_rc_add(); in the
   *       IRQ handler we use that to determine if the hw is ready to
   *       handle events. Looks like a race condition, but it really is
   *       not.
   */
  static
  int whcrc_probe(struct umc_dev *umc_dev)
  {
  	int result;
  	struct uwb_rc *uwb_rc;
  	struct whcrc *whcrc;
  	struct device *dev = &umc_dev->dev;

  	result = -ENOMEM;
  	uwb_rc = uwb_rc_alloc();
  	if (uwb_rc == NULL) {
  		dev_err(dev, "unable to allocate RC instance
  ");
  		goto error_rc_alloc;
  	}
  	whcrc = kzalloc(sizeof(*whcrc), GFP_KERNEL);
  	if (whcrc == NULL) {
  		dev_err(dev, "unable to allocate WHC-RC instance
  ");
  		goto error_alloc;
  	}
  	whcrc_init(whcrc);
  	whcrc->umc_dev = umc_dev;
  
  	result = whcrc_setup_rc_umc(whcrc);
  	if (result < 0) {
  		dev_err(dev, "Can't setup RC UMC interface: %d
  ", result);
  		goto error_setup_rc_umc;
  	}
  	whcrc->uwb_rc = uwb_rc;
  
  	uwb_rc->owner = THIS_MODULE;
  	uwb_rc->cmd   = whcrc_cmd;
  	uwb_rc->reset = whcrc_reset;
  	uwb_rc->start = whcrc_start_rc;
  	uwb_rc->stop  = whcrc_stop_rc;
  
  	result = uwb_rc_add(uwb_rc, dev, whcrc);
  	if (result < 0)
  		goto error_rc_add;
  	umc_set_drvdata(umc_dev, whcrc);

  	return 0;
  
  error_rc_add:
  	whcrc_release_rc_umc(whcrc);
  error_setup_rc_umc:
  	kfree(whcrc);
  error_alloc:
  	uwb_rc_put(uwb_rc);
  error_rc_alloc:

  	return result;
  }
  
  /**
   * Clean up the radio control resources
   *
   * When we up the command semaphore, everybody possibly held trying to
   * execute a command should be granted entry and then they'll see the
   * host is quiescing and up it (so it will chain to the next waiter).
   * This should not happen (in any case), as we can only remove when
   * there are no handles open...
   */
  static void whcrc_remove(struct umc_dev *umc_dev)
  {
  	struct whcrc *whcrc = umc_get_drvdata(umc_dev);
  	struct uwb_rc *uwb_rc = whcrc->uwb_rc;
  
  	umc_set_drvdata(umc_dev, NULL);
  	uwb_rc_rm(uwb_rc);
  	whcrc_release_rc_umc(whcrc);
  	kfree(whcrc);
  	uwb_rc_put(uwb_rc);

  }

  static int whcrc_pre_reset(struct umc_dev *umc)
  {
  	struct whcrc *whcrc = umc_get_drvdata(umc);
  	struct uwb_rc *uwb_rc = whcrc->uwb_rc;
  
  	uwb_rc_pre_reset(uwb_rc);
  	return 0;
  }
  
  static int whcrc_post_reset(struct umc_dev *umc)
  {
  	struct whcrc *whcrc = umc_get_drvdata(umc);
  	struct uwb_rc *uwb_rc = whcrc->uwb_rc;

  	return uwb_rc_post_reset(uwb_rc);

  }

  /* PCI device ID's that we handle [so it gets loaded] */

  static struct pci_device_id __used whcrc_id_table[] = {

  	{ PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
  	{ /* empty last entry */ }
  };
  MODULE_DEVICE_TABLE(pci, whcrc_id_table);
  
  static struct umc_driver whcrc_driver = {

  	.name       = "whc-rc",
  	.cap_id     = UMC_CAP_ID_WHCI_RC,
  	.probe      = whcrc_probe,
  	.remove     = whcrc_remove,
  	.pre_reset  = whcrc_pre_reset,
  	.post_reset = whcrc_post_reset,

  };
  
  static int __init whcrc_driver_init(void)
  {
  	return umc_driver_register(&whcrc_driver);
  }
  module_init(whcrc_driver_init);
  
  static void __exit whcrc_driver_exit(void)
  {
  	umc_driver_unregister(&whcrc_driver);
  }
  module_exit(whcrc_driver_exit);
  
  MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
  MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver");
  MODULE_LICENSE("GPL");