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1/* SPDX-License-Identifier: GPL-2.0-only */2/*3 * Copyright 2008 Cisco Systems, Inc. All rights reserved.4 * Copyright 2007 Nuova Systems, Inc. All rights reserved.5 */6#ifndef _CQ_DESC_H_7#define _CQ_DESC_H_8 9/*10 * Completion queue descriptor types11 */12enum cq_desc_types {13 CQ_DESC_TYPE_WQ_ENET = 0,14 CQ_DESC_TYPE_DESC_COPY = 1,15 CQ_DESC_TYPE_WQ_EXCH = 2,16 CQ_DESC_TYPE_RQ_ENET = 3,17 CQ_DESC_TYPE_RQ_FCP = 4,18};19 20/* Completion queue descriptor: 16B21 *22 * All completion queues have this basic layout. The23 * type_specfic area is unique for each completion24 * queue type.25 */26struct cq_desc {27 __le16 completed_index;28 __le16 q_number;29 u8 type_specfic[11];30 u8 type_color;31};32 33#define CQ_DESC_TYPE_BITS 434#define CQ_DESC_TYPE_MASK ((1 << CQ_DESC_TYPE_BITS) - 1)35#define CQ_DESC_COLOR_MASK 136#define CQ_DESC_COLOR_SHIFT 737#define CQ_DESC_Q_NUM_BITS 1038#define CQ_DESC_Q_NUM_MASK ((1 << CQ_DESC_Q_NUM_BITS) - 1)39#define CQ_DESC_COMP_NDX_BITS 1240#define CQ_DESC_COMP_NDX_MASK ((1 << CQ_DESC_COMP_NDX_BITS) - 1)41 42static inline void cq_desc_dec(const struct cq_desc *desc_arg,43 u8 *type, u8 *color, u16 *q_number, u16 *completed_index)44{45 const struct cq_desc *desc = desc_arg;46 const u8 type_color = desc->type_color;47 48 *color = (type_color >> CQ_DESC_COLOR_SHIFT) & CQ_DESC_COLOR_MASK;49 50 /*51 * Make sure color bit is read from desc *before* other fields52 * are read from desc. Hardware guarantees color bit is last53 * bit (byte) written. Adding the rmb() prevents the compiler54 * and/or CPU from reordering the reads which would potentially55 * result in reading stale values.56 */57 58 rmb();59 60 *type = type_color & CQ_DESC_TYPE_MASK;61 *q_number = le16_to_cpu(desc->q_number) & CQ_DESC_Q_NUM_MASK;62 *completed_index = le16_to_cpu(desc->completed_index) &63 CQ_DESC_COMP_NDX_MASK;64}65 66#endif /* _CQ_DESC_H_ */67