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-rw-r--r--drivers/scsi/snic/cq_desc.h77
1 files changed, 77 insertions, 0 deletions
diff --git a/drivers/scsi/snic/cq_desc.h b/drivers/scsi/snic/cq_desc.h
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+++ b/drivers/scsi/snic/cq_desc.h
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+/*
+ * Copyright 2014 Cisco 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_specific area is unique for each completion
+ * queue type.
+ */
+struct cq_desc {
+ __le16 completed_index;
+ __le16 q_number;
+ u8 type_specific[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_ */