1 /* 2 * Copyright 2008-2010 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 */ 19 20 #ifndef _CQ_DESC_H_ 21 #define _CQ_DESC_H_ 22 23 /* 24 * Completion queue descriptor types 25 */ 26 enum cq_desc_types { 27 CQ_DESC_TYPE_WQ_ENET = 0, 28 CQ_DESC_TYPE_DESC_COPY = 1, 29 CQ_DESC_TYPE_WQ_EXCH = 2, 30 CQ_DESC_TYPE_RQ_ENET = 3, 31 CQ_DESC_TYPE_RQ_FCP = 4, 32 }; 33 34 /* Completion queue descriptor: 16B 35 * 36 * All completion queues have this basic layout. The 37 * type_specfic area is unique for each completion 38 * queue type. 39 */ 40 struct cq_desc { 41 __le16 completed_index; 42 __le16 q_number; 43 u8 type_specfic[11]; 44 u8 type_color; 45 }; 46 47 #define CQ_DESC_TYPE_BITS 4 48 #define CQ_DESC_TYPE_MASK ((1 << CQ_DESC_TYPE_BITS) - 1) 49 #define CQ_DESC_COLOR_MASK 1 50 #define CQ_DESC_COLOR_SHIFT 7 51 #define CQ_DESC_Q_NUM_BITS 10 52 #define CQ_DESC_Q_NUM_MASK ((1 << CQ_DESC_Q_NUM_BITS) - 1) 53 #define CQ_DESC_COMP_NDX_BITS 12 54 #define CQ_DESC_COMP_NDX_MASK ((1 << CQ_DESC_COMP_NDX_BITS) - 1) 55 56 static inline void cq_desc_dec(const struct cq_desc *desc_arg, 57 u8 *type, u8 *color, u16 *q_number, u16 *completed_index) 58 { 59 const struct cq_desc *desc = desc_arg; 60 const u8 type_color = desc->type_color; 61 62 *color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK; 63 64 /* 65 * Make sure color bit is read from desc *before* other fields 66 * are read from desc. Hardware guarantees color bit is last 67 * bit (byte) written. Adding the rmb() prevents the compiler 68 * and/or CPU from reordering the reads which would potentially 69 * result in reading stale values. 70 */ 71 72 rmb(); 73 74 *type = type_color & CQ_DESC_TYPE_MASK; 75 *q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK; 76 *completed_index = le16_to_cpu(desc->completed_index) & 77 CQ_DESC_COMP_NDX_MASK; 78 } 79 80 #endif /* _CQ_DESC_H_ */ 81