diff options
Diffstat (limited to 'drivers/scsi/fnic/cq_desc.h')
| -rw-r--r-- | drivers/scsi/fnic/cq_desc.h | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/drivers/scsi/fnic/cq_desc.h b/drivers/scsi/fnic/cq_desc.h new file mode 100644 index 000000000000..d1225cf6320e --- /dev/null +++ b/drivers/scsi/fnic/cq_desc.h @@ -0,0 +1,78 @@ +/* + * 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 _CQ_DESC_H_ +#define _CQ_DESC_H_ + +/* + * Completion queue descriptor types + */ +enum cq_desc_types { + CQ_DESC_TYPE_WQ_ENET = 0, + CQ_DESC_TYPE_DESC_COPY = 1, + CQ_DESC_TYPE_WQ_EXCH = 2, + CQ_DESC_TYPE_RQ_ENET = 3, + CQ_DESC_TYPE_RQ_FCP = 4, +}; + +/* Completion queue descriptor: 16B + * + * All completion queues have this basic layout. The + * type_specfic area is unique for each completion + * queue type. + */ +struct cq_desc { + __le16 completed_index; + __le16 q_number; + u8 type_specfic[11]; + u8 type_color; +}; + +#define CQ_DESC_TYPE_BITS 4 +#define CQ_DESC_TYPE_MASK ((1 << CQ_DESC_TYPE_BITS) - 1) +#define CQ_DESC_COLOR_MASK 1 +#define CQ_DESC_COLOR_SHIFT 7 +#define CQ_DESC_Q_NUM_BITS 10 +#define CQ_DESC_Q_NUM_MASK ((1 << CQ_DESC_Q_NUM_BITS) - 1) +#define CQ_DESC_COMP_NDX_BITS 12 +#define CQ_DESC_COMP_NDX_MASK ((1 << CQ_DESC_COMP_NDX_BITS) - 1) + +static inline void cq_desc_dec(const struct cq_desc *desc_arg, + u8 *type, u8 *color, u16 *q_number, u16 *completed_index) +{ + const struct cq_desc *desc = desc_arg; + const u8 type_color = desc->type_color; + + *color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK; + + /* + * Make sure color bit is read from desc *before* other fields + * are read from desc. Hardware guarantees color bit is last + * bit (byte) written. Adding the rmb() prevents the compiler + * and/or CPU from reordering the reads which would potentially + * result in reading stale values. + */ + + rmb(); + + *type = type_color & CQ_DESC_TYPE_MASK; + *q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK; + *completed_index = le16_to_cpu(desc->completed_index) & + CQ_DESC_COMP_NDX_MASK; +} + +#endif /* _CQ_DESC_H_ */ |