Soft RoCE driver

Soft RoCE (RXE) - The software RoCE driver

ib_rxe implements the RDMA transport and registers to the RDMA core
device as a kernel verbs provider. It also implements the packet IO
layer. On the other hand ib_rxe registers to the Linux netdev stack
as a udp encapsulating protocol, in that case RDMA, for sending and
receiving packets over any Ethernet device.  This yields a RDMA
transport over the UDP/Ethernet network layer forming a RoCEv2
compatible device.

The configuration procedure of the Soft RoCE drivers requires
binding to any existing Ethernet network device. This is done with
/sys interface.

A userspace Soft RoCE library (librxe) provides user applications
the ability to run with Soft RoCE devices.  The use of rxe verbs ins
user space requires the inclusion of librxe as a device specifics
plug-in to libibverbs. librxe is packaged separately.

Architecture:

     +-----------------------------------------------------------+
     |                          Application                      |
     +-----------------------------------------------------------+
                            +-----------------------------------+
                            |             libibverbs            |
User                        +-----------------------------------+
                            +----------------+ +----------------+
                            | librxe         | | HW RoCE lib    |
                            +----------------+ +----------------+
+---------------------------------------------------------------+
     +--------------+                           +------------+
     | Sockets      |                           | RDMA ULP   |
     +--------------+                           +------------+
     +--------------+                  +---------------------+
     | TCP/IP       |                  | ib_core             |
     +--------------+                  +---------------------+
                             +------------+ +----------------+
Kernel                       | ib_rxe     | | HW RoCE driver |
                             +------------+ +----------------+
     +------------------------------------+
     | NIC driver                         |
     +------------------------------------+

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     +-----------------------------------------------------------+
     |                          Application                      |
     +-----------------------------------------------------------+
                            +-----------------------------------+
                            |             libibverbs            |
User                        +-----------------------------------+
                            +----------------+ +----------------+
                            | librxe         | | HW RoCE lib    |
                            +----------------+ +----------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     +--------------+                           +------------+
     | Sockets      |                           | RDMA ULP   |
     +--------------+                           +------------+
     +--------------+                  +---------------------+
     | TCP/IP       |                  | ib_core             |
     +--------------+                  +---------------------+
                             +------------+ +----------------+
Kernel                       | ib_rxe     | | HW RoCE driver |
                             +------------+ +----------------+
     +------------------------------------+
     | NIC driver                         |
     +------------------------------------+
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Soft RoCE resources:

[1[ https://github.com/SoftRoCE/librxe-dev librxe - source code in
Github
[2] https://github.com/SoftRoCE/rxe-dev/wiki/rxe-dev:-Home - Soft RoCE
Wiki page
[3] https://github.com/SoftRoCE/librxe-dev - Soft RoCE userspace library

Signed-off-by: Kamal Heib <kamalh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: Moni Shoua <monis@mellanox.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/drivers/infiniband/sw/rxe/rxe_task.h b/drivers/infiniband/sw/rxe/rxe_task.h
new file mode 100644
index 000000000000..d14aa6daed05
--- /dev/null
+++ b/drivers/infiniband/sw/rxe/rxe_task.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2016 Mellanox Technologies Ltd. All rights reserved.
+ * Copyright (c) 2015 System Fabric Works, 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 RXE_TASK_H
+#define RXE_TASK_H
+
+enum {
+	TASK_STATE_START	= 0,
+	TASK_STATE_BUSY		= 1,
+	TASK_STATE_ARMED	= 2,
+};
+
+/*
+ * data structure to describe a 'task' which is a short
+ * function that returns 0 as long as it needs to be
+ * called again.
+ */
+struct rxe_task {
+	void			*obj;
+	struct tasklet_struct	tasklet;
+	int			state;
+	spinlock_t		state_lock; /* spinlock for task state */
+	void			*arg;
+	int			(*func)(void *arg);
+	int			ret;
+	char			name[16];
+};
+
+/*
+ * init rxe_task structure
+ *	arg  => parameter to pass to fcn
+ *	fcn  => function to call until it returns != 0
+ */
+int rxe_init_task(void *obj, struct rxe_task *task,
+		  void *arg, int (*func)(void *), char *name);
+
+/* cleanup task */
+void rxe_cleanup_task(struct rxe_task *task);
+
+/*
+ * raw call to func in loop without any checking
+ * can call when tasklets are disabled
+ */
+int __rxe_do_task(struct rxe_task *task);
+
+/*
+ * common function called by any of the main tasklets
+ * If there is any chance that there is additional
+ * work to do someone must reschedule the task before
+ * leaving
+ */
+void rxe_do_task(unsigned long data);
+
+/* run a task, else schedule it to run as a tasklet, The decision
+ * to run or schedule tasklet is based on the parameter sched.
+ */
+void rxe_run_task(struct rxe_task *task, int sched);
+
+/* keep a task from scheduling */
+void rxe_disable_task(struct rxe_task *task);
+
+/* allow task to run */
+void rxe_enable_task(struct rxe_task *task);
+
+#endif /* RXE_TASK_H */