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kernel/linux-rt-4.4.41/drivers/scsi/fnic/vnic_wq_copy.h 3.69 KB
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  /*
   * Copyright 2008 Cisco Systems, Inc.  All rights reserved.
   * Copyright 2007 Nuova Systems, Inc.  All rights reserved.
   *
   * This program is free software; you may redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  #ifndef _VNIC_WQ_COPY_H_
  #define _VNIC_WQ_COPY_H_
  
  #include <linux/pci.h>
  #include "vnic_wq.h"
  #include "fcpio.h"
  
  #define	VNIC_WQ_COPY_MAX 1
  
  struct vnic_wq_copy {
  	unsigned int index;
  	struct vnic_dev *vdev;
  	struct vnic_wq_ctrl __iomem *ctrl;	/* memory-mapped */
  	struct vnic_dev_ring ring;
  	unsigned to_use_index;
  	unsigned to_clean_index;
  };
  
  static inline unsigned int vnic_wq_copy_desc_avail(struct vnic_wq_copy *wq)
  {
  	return wq->ring.desc_avail;
  }
  
  static inline unsigned int vnic_wq_copy_desc_in_use(struct vnic_wq_copy *wq)
  {
  	return wq->ring.desc_count - 1 - wq->ring.desc_avail;
  }
  
  static inline void *vnic_wq_copy_next_desc(struct vnic_wq_copy *wq)
  {
  	struct fcpio_host_req *desc = wq->ring.descs;
  	return &desc[wq->to_use_index];
  }
  
  static inline void vnic_wq_copy_post(struct vnic_wq_copy *wq)
  {
  
  	((wq->to_use_index + 1) == wq->ring.desc_count) ?
  		(wq->to_use_index = 0) : (wq->to_use_index++);
  	wq->ring.desc_avail--;
  
  	/* Adding write memory barrier prevents compiler and/or CPU
  	 * reordering, thus avoiding descriptor posting before
  	 * descriptor is initialized. Otherwise, hardware can read
  	 * stale descriptor fields.
  	 */
  	wmb();
  
  	iowrite32(wq->to_use_index, &wq->ctrl->posted_index);
  }
  
  static inline void vnic_wq_copy_desc_process(struct vnic_wq_copy *wq, u16 index)
  {
  	unsigned int cnt;
  
  	if (wq->to_clean_index <= index)
  		cnt = (index - wq->to_clean_index) + 1;
  	else
  		cnt = wq->ring.desc_count - wq->to_clean_index + index + 1;
  
  	wq->to_clean_index = ((index + 1) % wq->ring.desc_count);
  	wq->ring.desc_avail += cnt;
  
  }
  
  static inline void vnic_wq_copy_service(struct vnic_wq_copy *wq,
  	u16 completed_index,
  	void (*q_service)(struct vnic_wq_copy *wq,
  	struct fcpio_host_req *wq_desc))
  {
  	struct fcpio_host_req *wq_desc = wq->ring.descs;
  	unsigned int curr_index;
  
  	while (1) {
  
  		if (q_service)
  			(*q_service)(wq, &wq_desc[wq->to_clean_index]);
  
  		wq->ring.desc_avail++;
  
  		curr_index = wq->to_clean_index;
  
  		/* increment the to-clean index so that we start
  		 * with an unprocessed index next time we enter the loop
  		 */
  		((wq->to_clean_index + 1) == wq->ring.desc_count) ?
  			(wq->to_clean_index = 0) : (wq->to_clean_index++);
  
  		if (curr_index == completed_index)
  			break;
  
  		/* we have cleaned all the entries */
  		if ((completed_index == (u16)-1) &&
  		    (wq->to_clean_index == wq->to_use_index))
  			break;
  	}
  }
  
  void vnic_wq_copy_enable(struct vnic_wq_copy *wq);
  int vnic_wq_copy_disable(struct vnic_wq_copy *wq);
  void vnic_wq_copy_free(struct vnic_wq_copy *wq);
  int vnic_wq_copy_alloc(struct vnic_dev *vdev, struct vnic_wq_copy *wq,
  	unsigned int index, unsigned int desc_count, unsigned int desc_size);
  void vnic_wq_copy_init(struct vnic_wq_copy *wq, unsigned int cq_index,
  	unsigned int error_interrupt_enable,
  	unsigned int error_interrupt_offset);
  void vnic_wq_copy_clean(struct vnic_wq_copy *wq,
  	void (*q_clean)(struct vnic_wq_copy *wq,
  	struct fcpio_host_req *wq_desc));
  
  #endif /* _VNIC_WQ_COPY_H_ */