/*

   * zfcp device driver

   *

   * Setup and helper functions to access QDIO.

   *

   * Copyright IBM Corporation 2002, 2009

   */

  #define KMSG_COMPONENT "zfcp"
  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

  #include "zfcp_ext.h"

  #include "zfcp_qdio.h"

  #define QBUFF_PER_PAGE		(PAGE_SIZE / sizeof(struct qdio_buffer))

  static int zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbal)

  {

  	int pos;

  	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {

  		sbal[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
  		if (!sbal[pos])

  			return -ENOMEM;

  	}
  	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
  		if (pos % QBUFF_PER_PAGE)

  			sbal[pos] = sbal[pos - 1] + 1;

  	return 0;

  }

  static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *id)

  {

  	struct zfcp_adapter *adapter = qdio->adapter;

  	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred
  ");

  	zfcp_erp_adapter_reopen(adapter,
  				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
  				ZFCP_STATUS_COMMON_ERP_FAILED, id, NULL);

  }

  static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
  {
  	int i, sbal_idx;
  
  	for (i = first; i < first + cnt; i++) {
  		sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
  		memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
  	}
  }

  /* this needs to be called prior to updating the queue fill level */

  static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)

  {

  	unsigned long long now, span;

  	int free, used;

  	spin_lock(&qdio->stat_lock);

  	now = get_clock_monotonic();
  	span = (now - qdio->req_q_time) >> 12;
  	free = atomic_read(&qdio->req_q.count);

  	used = QDIO_MAX_BUFFERS_PER_Q - free;

  	qdio->req_q_util += used * span;
  	qdio->req_q_time = now;
  	spin_unlock(&qdio->stat_lock);

  }

  static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
  			      int queue_no, int first, int count,

  			      unsigned long parm)

  {

  	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
  	struct zfcp_qdio_queue *queue = &qdio->req_q;

  	if (unlikely(qdio_err)) {

  		zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
  					count);

  		zfcp_qdio_handler_error(qdio, "qdireq1");

  		return;
  	}

  
  	/* cleanup all SBALs being program-owned now */

  	zfcp_qdio_zero_sbals(queue->sbal, first, count);

  	zfcp_qdio_account(qdio);

  	atomic_add(count, &queue->count);

  	wake_up(&qdio->req_q_wq);

  }

  static void zfcp_qdio_resp_put_back(struct zfcp_qdio *qdio, int processed)

  {

  	struct zfcp_qdio_queue *queue = &qdio->resp_q;
  	struct ccw_device *cdev = qdio->adapter->ccw_device;

  	u8 count, start = queue->first;
  	unsigned int retval;

  	count = atomic_read(&queue->count) + processed;

  	retval = do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, start, count);

  
  	if (unlikely(retval)) {
  		atomic_set(&queue->count, count);

  		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdrpb_1", NULL);

  	} else {
  		queue->first += count;
  		queue->first %= QDIO_MAX_BUFFERS_PER_Q;
  		atomic_set(&queue->count, 0);
  	}
  }

  static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
  			       int queue_no, int first, int count,

  			       unsigned long parm)
  {

  	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;

  	int sbal_idx, sbal_no;

  	if (unlikely(qdio_err)) {

  		zfcp_dbf_hba_qdio(qdio->adapter->dbf, qdio_err, first,
  					count);

  		zfcp_qdio_handler_error(qdio, "qdires1");

  		return;
  	}

  	/*
  	 * go through all SBALs from input queue currently
  	 * returned by QDIO layer
  	 */

  	for (sbal_no = 0; sbal_no < count; sbal_no++) {
  		sbal_idx = (first + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;

  		/* go through all SBALEs of SBAL */

  		zfcp_fsf_reqid_check(qdio, sbal_idx);

  	}
  
  	/*
  	 * put range of SBALs back to response queue
  	 * (including SBALs which have already been free before)
  	 */

  	zfcp_qdio_resp_put_back(qdio, count);

  }

  static void zfcp_qdio_sbal_limit(struct zfcp_qdio *qdio,

  				 struct zfcp_qdio_req *q_req, int max_sbals)

  {

  	int count = atomic_read(&qdio->req_q.count);

  	count = min(count, max_sbals);

  	q_req->sbal_limit = (q_req->sbal_first + count - 1)

  					% QDIO_MAX_BUFFERS_PER_Q;

  }

  static struct qdio_buffer_element *

  zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,

  		     unsigned long sbtype)

  {

  	struct qdio_buffer_element *sbale;

  
  	/* set last entry flag in current SBALE of current SBAL */

  	sbale = zfcp_qdio_sbale_curr(qdio, q_req);

  	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;
  
  	/* don't exceed last allowed SBAL */

  	if (q_req->sbal_last == q_req->sbal_limit)

  		return NULL;
  
  	/* set chaining flag in first SBALE of current SBAL */

  	sbale = zfcp_qdio_sbale_req(qdio, q_req);

  	sbale->flags |= SBAL_FLAGS0_MORE_SBALS;
  
  	/* calculate index of next SBAL */

  	q_req->sbal_last++;
  	q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

  
  	/* keep this requests number of SBALs up-to-date */

  	q_req->sbal_number++;

  
  	/* start at first SBALE of new SBAL */

  	q_req->sbale_curr = 0;

  
  	/* set storage-block type for new SBAL */

  	sbale = zfcp_qdio_sbale_curr(qdio, q_req);

  	sbale->flags |= sbtype;
  
  	return sbale;
  }

  static struct qdio_buffer_element *

  zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,

  		     unsigned int sbtype)

  {

  	if (q_req->sbale_curr == ZFCP_LAST_SBALE_PER_SBAL)

  		return zfcp_qdio_sbal_chain(qdio, q_req, sbtype);

  	q_req->sbale_curr++;

  	return zfcp_qdio_sbale_curr(qdio, q_req);

  }

  static void zfcp_qdio_undo_sbals(struct zfcp_qdio *qdio,

  				 struct zfcp_qdio_req *q_req)

  {

  	struct qdio_buffer **sbal = qdio->req_q.sbal;

  	int first = q_req->sbal_first;
  	int last = q_req->sbal_last;

  	int count = (last - first + QDIO_MAX_BUFFERS_PER_Q) %
  		QDIO_MAX_BUFFERS_PER_Q + 1;
  	zfcp_qdio_zero_sbals(sbal, first, count);

  }

  static int zfcp_qdio_fill_sbals(struct zfcp_qdio *qdio,

  				struct zfcp_qdio_req *q_req,

  				unsigned int sbtype, void *start_addr,
  				unsigned int total_length)

  {

  	struct qdio_buffer_element *sbale;

  	unsigned long remaining, length;
  	void *addr;

  	/* split segment up */

  	for (addr = start_addr, remaining = total_length; remaining > 0;
  	     addr += length, remaining -= length) {

  		sbale = zfcp_qdio_sbale_next(qdio, q_req, sbtype);

  		if (!sbale) {

  			atomic_inc(&qdio->req_q_full);
  			zfcp_qdio_undo_sbals(qdio, q_req);

  			return -EINVAL;
  		}

  
  		/* new piece must not exceed next page boundary */

  		length = min(remaining,

  			     (PAGE_SIZE - ((unsigned long)addr &

  					   (PAGE_SIZE - 1))));

  		sbale->addr = addr;
  		sbale->length = length;

  	}

  	return 0;

  }

  /**
   * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
   * @fsf_req: request to be processed
   * @sbtype: SBALE flags
   * @sg: scatter-gather list

   * @max_sbals: upper bound for number of SBALs to be used

   * Returns: number of bytes, or error (negativ)

   */

  int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,

  			    unsigned long sbtype, struct scatterlist *sg,
  			    int max_sbals)

  {

  	struct qdio_buffer_element *sbale;

  	int retval, bytes = 0;

  
  	/* figure out last allowed SBAL */

  	zfcp_qdio_sbal_limit(qdio, q_req, max_sbals);

  	/* set storage-block type for this request */

  	sbale = zfcp_qdio_sbale_req(qdio, q_req);

  	sbale->flags |= sbtype;

  	for (; sg; sg = sg_next(sg)) {

  		retval = zfcp_qdio_fill_sbals(qdio, q_req, sbtype,

  					      sg_virt(sg), sg->length);

  		if (retval < 0)
  			return retval;
  		bytes += sg->length;

  	}

  	/* assume that no other SBALEs are to follow in the same SBAL */

  	sbale = zfcp_qdio_sbale_curr(qdio, q_req);

  	sbale->flags |= SBAL_FLAGS_LAST_ENTRY;

  	return bytes;
  }

  /**

   * zfcp_qdio_send - set PCI flag in first SBALE and send req to QDIO

   * @qdio: pointer to struct zfcp_qdio

   * @q_req: pointer to struct zfcp_qdio_req

   * Returns: 0 on success, error otherwise

   */

  int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)

  {

  	struct zfcp_qdio_queue *req_q = &qdio->req_q;

  	int first = q_req->sbal_first;
  	int count = q_req->sbal_number;

  	int retval;
  	unsigned int qdio_flags = QDIO_FLAG_SYNC_OUTPUT;

  	zfcp_qdio_account(qdio);

  	retval = do_QDIO(qdio->adapter->ccw_device, qdio_flags, 0, first,
  			 count);

  	if (unlikely(retval)) {
  		zfcp_qdio_zero_sbals(req_q->sbal, first, count);
  		return retval;
  	}
  
  	/* account for transferred buffers */
  	atomic_sub(count, &req_q->count);
  	req_q->first += count;
  	req_q->first %= QDIO_MAX_BUFFERS_PER_Q;

  	return 0;

  }

  
  static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
  				      struct zfcp_qdio *qdio)
  {
  
  	id->cdev = qdio->adapter->ccw_device;
  	id->q_format = QDIO_ZFCP_QFMT;
  	memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
  	ASCEBC(id->adapter_name, 8);
  	id->qib_param_field_format = 0;
  	id->qib_param_field = NULL;
  	id->input_slib_elements = NULL;
  	id->output_slib_elements = NULL;
  	id->no_input_qs = 1;
  	id->no_output_qs = 1;
  	id->input_handler = zfcp_qdio_int_resp;
  	id->output_handler = zfcp_qdio_int_req;
  	id->int_parm = (unsigned long) qdio;
  	id->flags = QDIO_INBOUND_0COPY_SBALS |
  		    QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
  	id->input_sbal_addr_array = (void **) (qdio->resp_q.sbal);
  	id->output_sbal_addr_array = (void **) (qdio->req_q.sbal);
  
  }

  /**

   * zfcp_qdio_allocate - allocate queue memory and initialize QDIO data
   * @adapter: pointer to struct zfcp_adapter
   * Returns: -ENOMEM on memory allocation error or return value from
   *          qdio_allocate
   */

  static int zfcp_qdio_allocate(struct zfcp_qdio *qdio)

  {

  	struct qdio_initialize init_data;

  	if (zfcp_qdio_buffers_enqueue(qdio->req_q.sbal) ||
  	    zfcp_qdio_buffers_enqueue(qdio->resp_q.sbal))

  		return -ENOMEM;

  	zfcp_qdio_setup_init_data(&init_data, qdio);
  
  	return qdio_allocate(&init_data);

  }
  
  /**
   * zfcp_close_qdio - close qdio queues for an adapter

   * @qdio: pointer to structure zfcp_qdio

   */

  void zfcp_qdio_close(struct zfcp_qdio *qdio)

  {

  	struct zfcp_qdio_queue *req_q;
  	int first, count;

  	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))

  		return;
  
  	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */

  	req_q = &qdio->req_q;
  	spin_lock_bh(&qdio->req_q_lock);
  	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
  	spin_unlock_bh(&qdio->req_q_lock);

  	qdio_shutdown(qdio->adapter->ccw_device,
  		      QDIO_FLAG_CLEANUP_USING_CLEAR);

  
  	/* cleanup used outbound sbals */
  	count = atomic_read(&req_q->count);
  	if (count < QDIO_MAX_BUFFERS_PER_Q) {
  		first = (req_q->first + count) % QDIO_MAX_BUFFERS_PER_Q;
  		count = QDIO_MAX_BUFFERS_PER_Q - count;
  		zfcp_qdio_zero_sbals(req_q->sbal, first, count);

  	}

  	req_q->first = 0;
  	atomic_set(&req_q->count, 0);

  	qdio->resp_q.first = 0;
  	atomic_set(&qdio->resp_q.count, 0);

  }

  /**
   * zfcp_qdio_open - prepare and initialize response queue

   * @qdio: pointer to struct zfcp_qdio

   * Returns: 0 on success, otherwise -EIO
   */

  int zfcp_qdio_open(struct zfcp_qdio *qdio)

  {

  	struct qdio_buffer_element *sbale;

  	struct qdio_initialize init_data;
  	struct ccw_device *cdev = qdio->adapter->ccw_device;

  	int cc;

  	if (atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)

  		return -EIO;

  	zfcp_qdio_setup_init_data(&init_data, qdio);
  
  	if (qdio_establish(&init_data))

  		goto failed_establish;

  	if (qdio_activate(cdev))

  		goto failed_qdio;

  
  	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {

  		sbale = &(qdio->resp_q.sbal[cc]->element[0]);

  		sbale->length = 0;
  		sbale->flags = SBAL_FLAGS_LAST_ENTRY;
  		sbale->addr = NULL;
  	}

  	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, 0,

  		     QDIO_MAX_BUFFERS_PER_Q))

  		goto failed_qdio;

  
  	/* set index of first avalable SBALS / number of available SBALS */

  	qdio->req_q.first = 0;
  	atomic_set(&qdio->req_q.count, QDIO_MAX_BUFFERS_PER_Q);

  
  	return 0;
  
  failed_qdio:

  	qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);

  failed_establish:

  	dev_err(&cdev->dev,

  		"Setting up the QDIO connection to the FCP adapter failed
  ");

  	return -EIO;
  }

  
  void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
  {
  	struct qdio_buffer **sbal_req, **sbal_resp;
  	int p;
  
  	if (!qdio)
  		return;
  
  	if (qdio->adapter->ccw_device)
  		qdio_free(qdio->adapter->ccw_device);
  
  	sbal_req = qdio->req_q.sbal;
  	sbal_resp = qdio->resp_q.sbal;
  
  	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
  		free_page((unsigned long) sbal_req[p]);
  		free_page((unsigned long) sbal_resp[p]);
  	}
  
  	kfree(qdio);
  }
  
  int zfcp_qdio_setup(struct zfcp_adapter *adapter)
  {
  	struct zfcp_qdio *qdio;
  
  	qdio = kzalloc(sizeof(struct zfcp_qdio), GFP_KERNEL);
  	if (!qdio)
  		return -ENOMEM;
  
  	qdio->adapter = adapter;
  
  	if (zfcp_qdio_allocate(qdio)) {
  		zfcp_qdio_destroy(qdio);
  		return -ENOMEM;
  	}
  
  	spin_lock_init(&qdio->req_q_lock);
  	spin_lock_init(&qdio->stat_lock);
  
  	adapter->qdio = qdio;
  	return 0;
  }