From: Steve Wise <swise@opengridcomputing.com>
Subject: [PATCH 7/7] AMSO1100: Privileged Verbs Queues.
Date: Wed, 31 May 2006 13:27:48 -0500
To: rdreier@cisco.com, mshefty@ichips.intel.com
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
       openib-general@openib.org
Message-Id: <20060531182748.3652.46671.stgit@stevo-desktop>
In-Reply-To: <20060531182733.3652.54755.stgit@stevo-desktop>
References: <20060531182733.3652.54755.stgit@stevo-desktop>
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---

 drivers/infiniband/hw/amso1100/c2_vq.c |  260 ++++++++++++++++++++++++++++++++
 drivers/infiniband/hw/amso1100/c2_vq.h |   63 ++++++++
 2 files changed, 323 insertions(+), 0 deletions(-)

diff --git a/drivers/infiniband/hw/amso1100/c2_vq.c b/drivers/infiniband/hw/amso1100/c2_vq.c
new file mode 100644
index 0000000..f98b531
--- /dev/null
+++ b/drivers/infiniband/hw/amso1100/c2_vq.c
@@ -0,0 +1,260 @@
+/*
+ * Copyright (c) 2005 Ammasso, Inc. All rights reserved.
+ * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     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.
+ *
+ * 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.
+ */
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#include "c2_vq.h"
+#include "c2_provider.h"
+
+/*
+ * Verbs Request Objects:
+ *
+ * VQ Request Objects are allocated by the kernel verbs handlers.
+ * They contain a wait object, a refcnt, an atomic bool indicating that the
+ * adapter has replied, and a copy of the verb reply work request.
+ * A pointer to the VQ Request Object is passed down in the context
+ * field of the work request message, and reflected back by the adapter
+ * in the verbs reply message.  The function handle_vq() in the interrupt
+ * path will use this pointer to:
+ * 	1) append a copy of the verbs reply message
+ * 	2) mark that the reply is ready
+ * 	3) wake up the kernel verbs handler blocked awaiting the reply.
+ *
+ *
+ * The kernel verbs handlers do a "get" to put a 2nd reference on the 
+ * VQ Request object.  If the kernel verbs handler exits before the adapter
+ * can respond, this extra reference will keep the VQ Request object around
+ * until the adapter's reply can be processed.  The reason we need this is
+ * because a pointer to this object is stuffed into the context field of
+ * the verbs work request message, and reflected back in the reply message.
+ * It is used in the interrupt handler (handle_vq()) to wake up the appropriate
+ * kernel verb handler that is blocked awaiting the verb reply.  
+ * So handle_vq() will do a "put" on the object when it's done accessing it.
+ * NOTE:  If we guarantee that the kernel verb handler will never bail before 
+ *        getting the reply, then we don't need these refcnts.
+ *
+ *
+ * VQ Request objects are freed by the kernel verbs handlers only 
+ * after the verb has been processed, or when the adapter fails and
+ * does not reply.  
+ *
+ *
+ * Verbs Reply Buffers:
+ *
+ * VQ Reply bufs are local host memory copies of a 
+ * outstanding Verb Request reply
+ * message.  The are always allocated by the kernel verbs handlers, and _may_ be
+ * freed by either the kernel verbs handler -or- the interrupt handler.  The
+ * kernel verbs handler _must_ free the repbuf, then free the vq request object
+ * in that order.
+ */
+
+int vq_init(struct c2_dev *c2dev)
+{
+	sprintf(c2dev->vq_cache_name, "c2-vq:dev%c",
+		(char) ('0' + c2dev->devnum));
+	c2dev->host_msg_cache =
+	    kmem_cache_create(c2dev->vq_cache_name, c2dev->rep_vq.msg_size, 0,
+			      SLAB_HWCACHE_ALIGN, NULL, NULL);
+	if (c2dev->host_msg_cache == NULL) {
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void vq_term(struct c2_dev *c2dev)
+{
+	kmem_cache_destroy(c2dev->host_msg_cache);
+}
+
+/* vq_req_alloc - allocate a VQ Request Object and initialize it.
+ * The refcnt is set to 1.
+ */
+struct c2_vq_req *vq_req_alloc(struct c2_dev *c2dev)
+{
+	struct c2_vq_req *r;
+
+	r = kmalloc(sizeof(struct c2_vq_req), GFP_KERNEL);
+	if (r) {
+		init_waitqueue_head(&r->wait_object);
+		r->reply_msg = (u64) NULL;
+		r->event = 0;
+		r->cm_id = NULL;
+		r->qp = NULL;
+		atomic_set(&r->refcnt, 1);
+		atomic_set(&r->reply_ready, 0);
+	}
+	return r;
+}
+
+
+/* vq_req_free - free the VQ Request Object.  It is assumed the verbs handler
+ * has already free the VQ Reply Buffer if it existed.
+ */
+void vq_req_free(struct c2_dev *c2dev, struct c2_vq_req *r)
+{
+	r->reply_msg = (u64) NULL;
+	if (atomic_dec_and_test(&r->refcnt)) {
+		kfree(r);
+	}
+}
+
+/* vq_req_get - reference a VQ Request Object.  Done 
+ * only in the kernel verbs handlers.
+ */
+void vq_req_get(struct c2_dev *c2dev, struct c2_vq_req *r)
+{
+	atomic_inc(&r->refcnt);
+}
+
+
+/* vq_req_put - dereference and potentially free a VQ Request Object.
+ *
+ * This is only called by handle_vq() on the 
+ * interrupt when it is done processing
+ * a verb reply message.  If the associated 
+ * kernel verbs handler has already bailed,
+ * then this put will actually free the VQ 
+ * Request object _and_ the VQ Reply Buffer
+ * if it exists.
+ */
+void vq_req_put(struct c2_dev *c2dev, struct c2_vq_req *r)
+{
+	if (atomic_dec_and_test(&r->refcnt)) {
+		if (r->reply_msg != (u64) NULL)
+			vq_repbuf_free(c2dev,
+				       (void *) (unsigned long) r->reply_msg);
+		kfree(r);
+	}
+}
+
+
+/*
+ * vq_repbuf_alloc - allocate a VQ Reply Buffer.
+ */
+void *vq_repbuf_alloc(struct c2_dev *c2dev)
+{
+	return kmem_cache_alloc(c2dev->host_msg_cache, SLAB_ATOMIC);
+}
+
+/*
+ * vq_send_wr - post a verbs request message to the Verbs Request Queue.
+ * If a message is not available in the MQ, then block until one is available.
+ * NOTE: handle_mq() on the interrupt context will wake up threads blocked here.
+ * When the adapter drains the Verbs Request Queue, 
+ * it inserts MQ index 0 in to the
+ * adapter->host activity fifo and interrupts the host.
+ */
+int vq_send_wr(struct c2_dev *c2dev, union c2wr *wr)
+{
+	void *msg;
+	wait_queue_t __wait;
+
+	/*
+	 * grab adapter vq lock
+	 */
+	spin_lock(&c2dev->vqlock);
+
+	/*
+	 * allocate msg
+	 */
+	msg = c2_mq_alloc(&c2dev->req_vq);
+
+	/*
+	 * If we cannot get a msg, then we'll wait
+	 * When a messages are available, the int handler will wake_up() 
+	 * any waiters.
+	 */
+	while (msg == NULL) {
+		dprintk("%s:%d no available msg in VQ, waiting...\n",
+		       __FUNCTION__, __LINE__);
+		init_waitqueue_entry(&__wait, current);
+		add_wait_queue(&c2dev->req_vq_wo, &__wait);
+		spin_unlock(&c2dev->vqlock);
+		for (;;) {
+			set_current_state(TASK_INTERRUPTIBLE);
+			if (!c2_mq_full(&c2dev->req_vq)) {
+				break;
+			}
+			if (!signal_pending(current)) {
+				schedule_timeout(1 * HZ);	/* 1 second... */
+				continue;
+			}
+			set_current_state(TASK_RUNNING);
+			remove_wait_queue(&c2dev->req_vq_wo, &__wait);
+			return -EINTR;
+		}
+		set_current_state(TASK_RUNNING);
+		remove_wait_queue(&c2dev->req_vq_wo, &__wait);
+		spin_lock(&c2dev->vqlock);
+		msg = c2_mq_alloc(&c2dev->req_vq);
+	}
+
+	/*
+	 * copy wr into adapter msg
+	 */
+	memcpy(msg, wr, c2dev->req_vq.msg_size);
+
+	/*
+	 * post msg
+	 */
+	c2_mq_produce(&c2dev->req_vq);
+
+	/*
+	 * release adapter vq lock
+	 */
+	spin_unlock(&c2dev->vqlock);
+	return 0;
+}
+
+
+/*
+ * vq_wait_for_reply - block until the adapter posts a Verb Reply Message.  
+ */
+int vq_wait_for_reply(struct c2_dev *c2dev, struct c2_vq_req *req)
+{
+	if (!wait_event_timeout(req->wait_object,
+				atomic_read(&req->reply_ready),
+				60*HZ))
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+/*
+ * vq_repbuf_free - Free a Verbs Reply Buffer.
+ */
+void vq_repbuf_free(struct c2_dev *c2dev, void *reply)
+{
+	kmem_cache_free(c2dev->host_msg_cache, reply);
+}
diff --git a/drivers/infiniband/hw/amso1100/c2_vq.h b/drivers/infiniband/hw/amso1100/c2_vq.h
new file mode 100644
index 0000000..3380562
--- /dev/null
+++ b/drivers/infiniband/hw/amso1100/c2_vq.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (c) 2005 Ammasso, Inc. All rights reserved.
+ * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     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.
+ *
+ * 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 _C2_VQ_H_
+#define _C2_VQ_H_
+#include <linux/sched.h>
+#include "c2.h"
+#include "c2_wr.h"
+#include "c2_provider.h"
+
+struct c2_vq_req {
+	u64 reply_msg;		/* ptr to reply msg */
+	wait_queue_head_t wait_object;	/* wait object for vq reqs */
+	atomic_t reply_ready;	/* set when reply is ready */
+	atomic_t refcnt;	/* used to cancel WRs... */
+	int event;
+	struct iw_cm_id *cm_id;
+	struct c2_qp *qp;
+};
+
+extern int vq_init(struct c2_dev *c2dev);
+extern void vq_term(struct c2_dev *c2dev);
+
+extern struct c2_vq_req *vq_req_alloc(struct c2_dev *c2dev);
+extern void vq_req_free(struct c2_dev *c2dev, struct c2_vq_req *req);
+extern void vq_req_get(struct c2_dev *c2dev, struct c2_vq_req *req);
+extern void vq_req_put(struct c2_dev *c2dev, struct c2_vq_req *req);
+extern int vq_send_wr(struct c2_dev *c2dev, union c2wr * wr);
+
+extern void *vq_repbuf_alloc(struct c2_dev *c2dev);
+extern void vq_repbuf_free(struct c2_dev *c2dev, void *reply);
+
+extern int vq_wait_for_reply(struct c2_dev *c2dev, struct c2_vq_req *req);
+#endif				/* _C2_VQ_H_ */
-
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