| Abhijeet Joglekar | 5df6d73 | 2009-04-17 18:33:26 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2008 Cisco Systems, Inc. All rights reserved. |
| 3 | * Copyright 2007 Nuova Systems, Inc. All rights reserved. |
| 4 | * |
| 5 | * This program is free software; you may redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License as published by |
| 7 | * the Free Software Foundation; version 2 of the License. |
| 8 | * |
| 9 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| 10 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| 11 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| 12 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
| 13 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
| 14 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
| 15 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| 16 | * SOFTWARE. |
| 17 | */ |
| 18 | #ifndef _CQ_DESC_H_ |
| 19 | #define _CQ_DESC_H_ |
| 20 | |
| 21 | /* |
| 22 | * Completion queue descriptor types |
| 23 | */ |
| 24 | enum cq_desc_types { |
| 25 | CQ_DESC_TYPE_WQ_ENET = 0, |
| 26 | CQ_DESC_TYPE_DESC_COPY = 1, |
| 27 | CQ_DESC_TYPE_WQ_EXCH = 2, |
| 28 | CQ_DESC_TYPE_RQ_ENET = 3, |
| 29 | CQ_DESC_TYPE_RQ_FCP = 4, |
| 30 | }; |
| 31 | |
| 32 | /* Completion queue descriptor: 16B |
| 33 | * |
| 34 | * All completion queues have this basic layout. The |
| 35 | * type_specfic area is unique for each completion |
| 36 | * queue type. |
| 37 | */ |
| 38 | struct cq_desc { |
| 39 | __le16 completed_index; |
| 40 | __le16 q_number; |
| 41 | u8 type_specfic[11]; |
| 42 | u8 type_color; |
| 43 | }; |
| 44 | |
| 45 | #define CQ_DESC_TYPE_BITS 4 |
| 46 | #define CQ_DESC_TYPE_MASK ((1 << CQ_DESC_TYPE_BITS) - 1) |
| 47 | #define CQ_DESC_COLOR_MASK 1 |
| 48 | #define CQ_DESC_COLOR_SHIFT 7 |
| 49 | #define CQ_DESC_Q_NUM_BITS 10 |
| 50 | #define CQ_DESC_Q_NUM_MASK ((1 << CQ_DESC_Q_NUM_BITS) - 1) |
| 51 | #define CQ_DESC_COMP_NDX_BITS 12 |
| 52 | #define CQ_DESC_COMP_NDX_MASK ((1 << CQ_DESC_COMP_NDX_BITS) - 1) |
| 53 | |
| 54 | static inline void cq_desc_dec(const struct cq_desc *desc_arg, |
| 55 | u8 *type, u8 *color, u16 *q_number, u16 *completed_index) |
| 56 | { |
| 57 | const struct cq_desc *desc = desc_arg; |
| 58 | const u8 type_color = desc->type_color; |
| 59 | |
| 60 | *color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK; |
| 61 | |
| 62 | /* |
| 63 | * Make sure color bit is read from desc *before* other fields |
| 64 | * are read from desc. Hardware guarantees color bit is last |
| 65 | * bit (byte) written. Adding the rmb() prevents the compiler |
| 66 | * and/or CPU from reordering the reads which would potentially |
| 67 | * result in reading stale values. |
| 68 | */ |
| 69 | |
| 70 | rmb(); |
| 71 | |
| 72 | *type = type_color & CQ_DESC_TYPE_MASK; |
| 73 | *q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK; |
| 74 | *completed_index = le16_to_cpu(desc->completed_index) & |
| 75 | CQ_DESC_COMP_NDX_MASK; |
| 76 | } |
| 77 | |
| 78 | #endif /* _CQ_DESC_H_ */ |