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+/*
+ * Copyright (c) 2012-2016 VMware, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of EITHER the GNU General Public License
+ * version 2 as published by the Free Software Foundation or the BSD
+ * 2-Clause License. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; WITHOUT EVEN THE IMPLIED
+ * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License version 2 for more details at
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program in the file COPYING. If not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ * The BSD 2-Clause License
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following
+ * disclaimer in the documentation and/or other materials
+ * provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __PVRDMA_RING_H__
+#define __PVRDMA_RING_H__
+
+#include <linux/types.h>
+
+#define PVRDMA_INVALID_IDX -1 /* Invalid index. */
+#define atomic_read(_x) *(_x)
+#define atomic_set(_x, _y) (*(_x) = (_y))
+
+typedef uint32_t atomic_t;
+
+struct pvrdma_ring {
+ atomic_t prod_tail; /* Producer tail. */
+ atomic_t cons_head; /* Consumer head. */
+};
+
+struct pvrdma_ring_state {
+ struct pvrdma_ring tx; /* Tx ring. */
+ struct pvrdma_ring rx; /* Rx ring. */
+};
+
+static inline int pvrdma_idx_valid(__u32 idx, __u32 max_elems)
+{
+ /* Generates fewer instructions than a less-than. */
+ return (idx & ~((max_elems << 1) - 1)) == 0;
+}
+
+static inline __s32 pvrdma_idx(atomic_t *var, __u32 max_elems)
+{
+ const unsigned idx = atomic_read(var);
+
+ if (pvrdma_idx_valid(idx, max_elems))
+ return idx & (max_elems - 1);
+ return PVRDMA_INVALID_IDX;
+}
+
+static inline void pvrdma_idx_ring_inc(atomic_t *var, __u32 max_elems)
+{
+ __u32 idx = atomic_read(var) + 1; /* Increment. */
+
+ idx &= (max_elems << 1) - 1; /* Modulo size, flip gen. */
+ atomic_set(var, idx);
+}
+
+static inline __s32 pvrdma_idx_ring_has_space(const struct pvrdma_ring *r,
+ __u32 max_elems, __u32 *out_tail)
+{
+ const __u32 tail = atomic_read(&r->prod_tail);
+ const __u32 head = atomic_read(&r->cons_head);
+
+ if (pvrdma_idx_valid(tail, max_elems) &&
+ pvrdma_idx_valid(head, max_elems)) {
+ *out_tail = tail & (max_elems - 1);
+ return tail != (head ^ max_elems);
+ }
+ return PVRDMA_INVALID_IDX;
+}
+
+static inline __s32 pvrdma_idx_ring_has_data(const struct pvrdma_ring *r,
+ __u32 max_elems, __u32 *out_head)
+{
+ const __u32 tail = atomic_read(&r->prod_tail);
+ const __u32 head = atomic_read(&r->cons_head);
+
+ if (pvrdma_idx_valid(tail, max_elems) &&
+ pvrdma_idx_valid(head, max_elems)) {
+ *out_head = head & (max_elems - 1);
+ return tail != head;
+ }
+ return PVRDMA_INVALID_IDX;
+}
+
+static inline __s32 pvrdma_idx_ring_is_valid_idx(const struct pvrdma_ring *r,
+ __u32 max_elems, __u32 *idx)
+{
+ const __u32 tail = atomic_read(&r->prod_tail);
+ const __u32 head = atomic_read(&r->cons_head);
+
+ if (pvrdma_idx_valid(tail, max_elems) &&
+ pvrdma_idx_valid(head, max_elems) &&
+ pvrdma_idx_valid(*idx, max_elems)) {
+ if (tail > head && (*idx < tail && *idx >= head))
+ return 1;
+ else if (head > tail && (*idx >= head || *idx < tail))
+ return 1;
+ }
+ return 0;
+}
+
+#endif /* __PVRDMA_RING_H__ */
CQs and QPs use these structures to traverse the CQE/WQE rings. Signed-off-by: Adit Ranadive <aditr@vmware.com> --- providers/pvrdma/pvrdma_ring.h | 136 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+) create mode 100644 providers/pvrdma/pvrdma_ring.h