text: /*
   * zfcp device driver
   *
   * Setup and helper functions to access QDIO.
   *
   * Copyright IBM Corp. 2002, 2010
   */
  
  #define KMSG_COMPONENT "zfcp"
  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  
  #include <linux/slab.h>
  #include <linux/module.h>
  #include "zfcp_ext.h"
  #include "zfcp_qdio.h"
  
  #define QBUFF_PER_PAGE		(PAGE_SIZE / sizeof(struct qdio_buffer))
  
  static bool enable_multibuffer = 1;
  module_param_named(datarouter, enable_multibuffer, bool, 0400);
  MODULE_PARM_DESC(datarouter, "Enable hardware data router support (default on)");
  
  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,
  				    unsigned int qdio_err)
  {
  	struct zfcp_adapter *adapter = qdio->adapter;
  
  	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");
  
  	if (qdio_err & QDIO_ERROR_SLSB_STATE) {
  		zfcp_qdio_siosl(adapter);
  		zfcp_erp_adapter_shutdown(adapter, 0, id);
  		return;
  	}
  	zfcp_erp_adapter_reopen(adapter,
  				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
  				ZFCP_STATUS_COMMON_ERP_FAILED, id);
  }
  
  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 used;
  
  	now = get_tod_clock_monotonic();
  	span = (now - qdio->req_q_time) >> 12;
  	used = QDIO_MAX_BUFFERS_PER_Q - atomic_read(&qdio->req_q_free);
  	qdio->req_q_util += used * span;
  	qdio->req_q_time = now;
  }
  
  static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
  			      int queue_no, int idx, int count,
  			      unsigned long parm)
  {
  	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
  
  	if (unlikely(qdio_err)) {
  		zfcp_qdio_handler_error(qdio, "qdireq1", qdio_err);
  		return;
  	}
  
  	/* cleanup all SBALs being program-owned now */
  	zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
  
  	spin_lock_irq(&qdio->stat_lock);
  	zfcp_qdio_account(qdio);
  	spin_unlock_irq(&qdio->stat_lock);
  	atomic_add(count, &qdio->req_q_free);
  	wake_up(&qdio->req_q_wq);
  }
  
  static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
  			       int queue_no, int idx, int count,
  			       unsigned long parm)
  {
  	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
  	struct zfcp_adapter *adapter = qdio->adapter;
  	int sbal_no, sbal_idx;
  
  	if (unlikely(qdio_err)) {
  		if (zfcp_adapter_multi_buffer_active(adapter)) {
  			void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
  			struct qdio_buffer_element *sbale;
  			u64 req_id;
  			u8 scount;
  
  			memset(pl, 0,
  			       ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
  			sbale = qdio->res_q[idx]->element;
  			req_id = (u64) sbale->addr;
  			scount = min(sbale->scount + 1,
  				     ZFCP_QDIO_MAX_SBALS_PER_REQ + 1);
  				     /* incl. signaling SBAL */
  
  			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
  				sbal_idx = (idx + sbal_no) %
  					QDIO_MAX_BUFFERS_PER_Q;
  				pl[sbal_no] = qdio->res_q[sbal_idx];
  			}
  			zfcp_dbf_hba_def_err(adapter, req_id, scount, pl);
  		}
  		zfcp_qdio_handler_error(qdio, "qdires1", qdio_err);
  		return;
  	}
  
  	/*
  	 * go through all SBALs from input queue currently
  	 * returned by QDIO layer
  	 */
  	for (sbal_no = 0; sbal_no < count; sbal_no++) {
  		sbal_idx = (idx + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
  		/* go through all SBALEs of SBAL */
  		zfcp_fsf_reqid_check(qdio, sbal_idx);
  	}
  
  	/*
  	 * put SBALs back to response queue
  	 */
  	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, idx, count))
  		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdires2");
  }
  
  static struct qdio_buffer_element *
  zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  {
  	struct qdio_buffer_element *sbale;
  
  	/* set last entry flag in current SBALE of current SBAL */
  	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
  	sbale->eflags |= SBAL_EFLAGS_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->sflags |= SBAL_SFLAGS0_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++;
  	BUG_ON(q_req->sbal_number > ZFCP_QDIO_MAX_SBALS_PER_REQ);
  
  	/* 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->sflags |= q_req->sbtype;
  
  	return sbale;
  }
  
  static struct qdio_buffer_element *
  zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
  {
  	if (q_req->sbale_curr == qdio->max_sbale_per_sbal - 1)
  		return zfcp_qdio_sbal_chain(qdio, q_req);
  	q_req->sbale_curr++;
  	return zfcp_qdio_sbale_curr(qdio, q_req);
  }
  
  /**
   * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
   * @qdio: pointer to struct zfcp_qdio
   * @q_req: pointer to struct zfcp_qdio_req
   * @sg: scatter-gather list
   * @max_sbals: upper bound for number of SBALs to be used
   * Returns: zero or -EINVAL on error
   */
  int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
  			    struct scatterlist *sg)
  {
  	struct qdio_buffer_element *sbale;
  
  	/* set storage-block type for this request */
  	sbale = zfcp_qdio_sbale_req(qdio, q_req);
  	sbale->sflags |= q_req->sbtype;
  
  	for (; sg; sg = sg_next(sg)) {
  		sbale = zfcp_qdio_sbale_next(qdio, q_req);
  		if (!sbale) {
  			atomic_inc(&qdio->req_q_full);
  			zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
  					     q_req->sbal_number);
  			return -EINVAL;
  		}
  		sbale->addr = sg_virt(sg);
  		sbale->length = sg->length;
  	}
  	return 0;
  }
  
  static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
  {
  	if (atomic_read(&qdio->req_q_free) ||
  	    !(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
  		return 1;
  	return 0;
  }
  
  /**
   * zfcp_qdio_sbal_get - get free sbal in request queue, wait if necessary
   * @qdio: pointer to struct zfcp_qdio
   *
   * The req_q_lock must be held by the caller of this function, and
   * this function may only be called from process context; it will
   * sleep when waiting for a free sbal.
   *
   * Returns: 0 on success, -EIO if there is no free sbal after waiting.
   */
  int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
  {
  	long ret;
  
  	ret = wait_event_interruptible_lock_irq_timeout(qdio->req_q_wq,
  		       zfcp_qdio_sbal_check(qdio), qdio->req_q_lock, 5 * HZ);
  
  	if (!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
  		return -EIO;
  
  	if (ret > 0)
  		return 0;
  
  	if (!ret) {
  		atomic_inc(&qdio->req_q_full);
  		/* assume hanging outbound queue, try queue recovery */
  		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdsbg_1");
  	}
  
  	return -EIO;
  }
  
  /**
   * 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)
  {
  	int retval;
  	u8 sbal_number = q_req->sbal_number;
  
  	spin_lock(&qdio->stat_lock);
  	zfcp_qdio_account(qdio);
  	spin_unlock(&qdio->stat_lock);
  
  	retval = do_QDIO(qdio->adapter->ccw_device, QDIO_FLAG_SYNC_OUTPUT, 0,
  			 q_req->sbal_first, sbal_number);
  
  	if (unlikely(retval)) {
  		zfcp_qdio_zero_sbals(qdio->req_q, q_req->sbal_first,
  				     sbal_number);
  		return retval;
  	}
  
  	/* account for transferred buffers */
  	atomic_sub(sbal_number, &qdio->req_q_free);
  	qdio->req_q_idx += sbal_number;
  	qdio->req_q_idx %= QDIO_MAX_BUFFERS_PER_Q;
  
  	return 0;
  }
  
  
  static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
  				      struct zfcp_qdio *qdio)
  {
  	memset(id, 0, sizeof(*id));
  	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_rflags = QIB_RFLAGS_ENABLE_DATA_DIV;
  	if (enable_multibuffer)
  		id->qdr_ac |= QDR_AC_MULTI_BUFFER_ENABLE;
  	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->input_sbal_addr_array = (void **) (qdio->res_q);
  	id->output_sbal_addr_array = (void **) (qdio->req_q);
  	id->scan_threshold =
  		QDIO_MAX_BUFFERS_PER_Q - ZFCP_QDIO_MAX_SBALS_PER_REQ * 2;
  }
  
  /**
   * 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) ||
  	    zfcp_qdio_buffers_enqueue(qdio->res_q))
  		return -ENOMEM;
  
  	zfcp_qdio_setup_init_data(&init_data, qdio);
  	init_waitqueue_head(&qdio->req_q_wq);
  
  	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_adapter *adapter = qdio->adapter;
  	int idx, count;
  
  	if (!(atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
  		return;
  
  	/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
  	spin_lock_irq(&qdio->req_q_lock);
  	atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
  	spin_unlock_irq(&qdio->req_q_lock);
  
  	wake_up(&qdio->req_q_wq);
  
  	qdio_shutdown(adapter->ccw_device, QDIO_FLAG_CLEANUP_USING_CLEAR);
  
  	/* cleanup used outbound sbals */
  	count = atomic_read(&qdio->req_q_free);
  	if (count < QDIO_MAX_BUFFERS_PER_Q) {
  		idx = (qdio->req_q_idx + count) % QDIO_MAX_BUFFERS_PER_Q;
  		count = QDIO_MAX_BUFFERS_PER_Q - count;
  		zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
  	}
  	qdio->req_q_idx = 0;
  	atomic_set(&qdio->req_q_free, 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 zfcp_adapter *adapter = qdio->adapter;
  	struct ccw_device *cdev = adapter->ccw_device;
  	struct qdio_ssqd_desc ssqd;
  	int cc;
  
  	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP)
  		return -EIO;
  
  	atomic_clear_mask(ZFCP_STATUS_ADAPTER_SIOSL_ISSUED,
  			  &qdio->adapter->status);
  
  	zfcp_qdio_setup_init_data(&init_data, qdio);
  
  	if (qdio_establish(&init_data))
  		goto failed_establish;
  
  	if (qdio_get_ssqd_desc(init_data.cdev, &ssqd))
  		goto failed_qdio;
  
  	if (ssqd.qdioac2 & CHSC_AC2_DATA_DIV_ENABLED)
  		atomic_set_mask(ZFCP_STATUS_ADAPTER_DATA_DIV_ENABLED,
  				&qdio->adapter->status);
  
  	if (ssqd.qdioac2 & CHSC_AC2_MULTI_BUFFER_ENABLED) {
  		atomic_set_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
  		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER;
  	} else {
  		atomic_clear_mask(ZFCP_STATUS_ADAPTER_MB_ACT, &adapter->status);
  		qdio->max_sbale_per_sbal = QDIO_MAX_ELEMENTS_PER_BUFFER - 1;
  	}
  
  	qdio->max_sbale_per_req =
  		ZFCP_QDIO_MAX_SBALS_PER_REQ * qdio->max_sbale_per_sbal
  		- 2;
  	if (qdio_activate(cdev))
  		goto failed_qdio;
  
  	for (cc = 0; cc < QDIO_MAX_BUFFERS_PER_Q; cc++) {
  		sbale = &(qdio->res_q[cc]->element[0]);
  		sbale->length = 0;
  		sbale->eflags = SBAL_EFLAGS_LAST_ENTRY;
  		sbale->sflags = 0;
  		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 available SBALS / number of available SBALS */
  	qdio->req_q_idx = 0;
  	atomic_set(&qdio->req_q_free, QDIO_MAX_BUFFERS_PER_Q);
  	atomic_set_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &qdio->adapter->status);
  
  	if (adapter->scsi_host) {
  		adapter->scsi_host->sg_tablesize = qdio->max_sbale_per_req;
  		adapter->scsi_host->max_sectors = qdio->max_sbale_per_req * 8;
  	}
  
  	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\n");
  	return -EIO;
  }
  
  void zfcp_qdio_destroy(struct zfcp_qdio *qdio)
  {
  	int p;
  
  	if (!qdio)
  		return;
  
  	if (qdio->adapter->ccw_device)
  		qdio_free(qdio->adapter->ccw_device);
  
  	for (p = 0; p < QDIO_MAX_BUFFERS_PER_Q; p += QBUFF_PER_PAGE) {
  		free_page((unsigned long) qdio->req_q[p]);
  		free_page((unsigned long) qdio->res_q[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;
  }
  
  /**
   * zfcp_qdio_siosl - Trigger logging in FCP channel
   * @adapter: The zfcp_adapter where to trigger logging
   *
   * Call the cio siosl function to trigger hardware logging.  This
   * wrapper function sets a flag to ensure hardware logging is only
   * triggered once before going through qdio shutdown.
   *
   * The triggers are always run from qdio tasklet context, so no
   * additional synchronization is necessary.
   */
  void zfcp_qdio_siosl(struct zfcp_adapter *adapter)
  {
  	int rc;
  
  	if (atomic_read(&adapter->status) & ZFCP_STATUS_ADAPTER_SIOSL_ISSUED)
  		return;
  
  	rc = ccw_device_siosl(adapter->ccw_device);
  	if (!rc)
  		atomic_set_mask(ZFCP_STATUS_ADAPTER_SIOSL_ISSUED,
  				&adapter->status);
  }
  