[PATCH v8 1/9] eal/bus: introduce bus abstraction

[Shreyansh Jain <shreyansh.jain@nxp.com>]

This patch introduces the rte_bus abstraction for EAL.
The model is:
 - One or more buses are connected to a CPU (or core)
 - One or more devices are conneted to a Bus
 - Drivers are running instances which manage one or more devices
 - Bus is responsible for identifying devices (and interrupt propogation)
 - Driver is responsible for initializing the device

This patch adds a 'rte_bus' base class which would be extended for
specific implementations. It also introduces Bus registration and
deregistration functions.

An example implementation would be like:

  .--------------->+-------------------+
  |                |rte_pci_bus        |
  |                | +----------------+|
  |                | |rte_bus         <------.
  |                | | name           ||     |
  |                | | scan           ||     |
  |                | | match          ||     |
  |                | | probe          ||     |
  |                | | remove         ||     |
  |                | | ...            ||     |
  |                | +----------------+|     |
  |                | pci_driver_list   |     |
  |  .-------------->pci_device_list   |     |
  |  |             | ...               |     |
  |  |             +-------------------+     |
  |  |                                       |
  |  +-------------------+                   |
  |  |rte_pci_device     |                   |
  '----bus               |                   |
     | +----------------+|                   |
     | |rte_device      ||                   |
     | | bus --------------------------------'
     | | ...            ||
     | +----------------+|
     | ...               |
     +-------------------+

Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
Reviewed-by: Ferruh Yigit <ferruh.yigit@intel.com>

---
 lib/librte_eal/bsdapp/eal/Makefile              |   1 +
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  10 +++
 lib/librte_eal/common/Makefile                  |   2 +-
 lib/librte_eal/common/eal_common_bus.c          |  97 +++++++++++++++++++++
 lib/librte_eal/common/include/rte_bus.h         | 111 ++++++++++++++++++++++++
 lib/librte_eal/common/include/rte_dev.h         |   1 +
 lib/librte_eal/linuxapp/eal/Makefile            |   1 +
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  10 +++
 8 files changed, 232 insertions(+), 1 deletion(-)
 create mode 100644 lib/librte_eal/common/eal_common_bus.c
 create mode 100644 lib/librte_eal/common/include/rte_bus.h

diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
index a15b762..cce99f7 100644
--- a/lib/librte_eal/bsdapp/eal/Makefile
+++ b/lib/librte_eal/bsdapp/eal/Makefile
@@ -78,6 +78,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_cpuflags.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_string_fns.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_hexdump.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_devargs.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_bus.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_dev.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_options.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_thread.c
diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 2f81f7c..4dcf653 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -174,3 +174,13 @@ DPDK_16.11 {
 	rte_eal_vdrv_unregister;
 
 } DPDK_16.07;
+
+DPDK_17.02 {
+	global:
+
+	rte_bus_list;
+	rte_bus_dump;
+	rte_bus_register;
+	rte_bus_unregister;
+
+} DPDK_16.11;
diff --git a/lib/librte_eal/common/Makefile b/lib/librte_eal/common/Makefile
index 09a3d3a..240995c 100644
--- a/lib/librte_eal/common/Makefile
+++ b/lib/librte_eal/common/Makefile
@@ -38,7 +38,7 @@ INC += rte_per_lcore.h rte_random.h
 INC += rte_tailq.h rte_interrupts.h rte_alarm.h
 INC += rte_string_fns.h rte_version.h
 INC += rte_eal_memconfig.h rte_malloc_heap.h
-INC += rte_hexdump.h rte_devargs.h rte_dev.h rte_vdev.h
+INC += rte_hexdump.h rte_devargs.h rte_bus.h rte_dev.h rte_vdev.h
 INC += rte_pci_dev_feature_defs.h rte_pci_dev_features.h
 INC += rte_malloc.h rte_keepalive.h rte_time.h
 
diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
new file mode 100644
index 0000000..c891392
--- /dev/null
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -0,0 +1,97 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2016 NXP
+ *   All rights reserved.
+ *
+ *   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.
+ *     * Neither the name of NXP nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   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
+ *   OWNER 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.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <inttypes.h>
+#include <sys/queue.h>
+
+#include <rte_bus.h>
+#include <rte_devargs.h>
+#include <rte_debug.h>
+
+#include "eal_private.h"
+
+struct rte_bus_list rte_bus_list =
+	TAILQ_HEAD_INITIALIZER(rte_bus_list);
+
+/* register a bus */
+void
+rte_bus_register(struct rte_bus *bus)
+{
+	RTE_VERIFY(bus);
+	RTE_VERIFY(bus->name && strlen(bus->name));
+
+	TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
+	RTE_LOG(INFO, EAL, "Registered [%s] bus.\n", bus->name);
+}
+
+/* unregister a bus */
+void
+rte_bus_unregister(struct rte_bus *bus)
+{
+	TAILQ_REMOVE(&rte_bus_list, bus, next);
+	RTE_LOG(INFO, EAL, "Unregistered [%s] bus.\n", bus->name);
+}
+
+/* dump one bus info */
+static int
+bus_dump_one(FILE *f, struct rte_bus *bus)
+{
+	int ret;
+
+	/* For now, dump only the bus name */
+	ret = fprintf(f, " %s\n", bus->name);
+
+	/* Error in case of inability in writing to stream */
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+void
+rte_bus_dump(FILE *f)
+{
+	int ret;
+	struct rte_bus *bus;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		ret = bus_dump_one(f, bus);
+		if (ret) {
+			RTE_LOG(ERR, EAL, "Unable to write to stream (%d)\n",
+				ret);
+			break;
+		}
+	}
+}
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
new file mode 100644
index 0000000..2250269
--- /dev/null
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -0,0 +1,111 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2016 NXP
+ *   All rights reserved.
+ *
+ *   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.
+ *     * Neither the name of NXP nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   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
+ *   OWNER 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 _RTE_BUS_H_
+#define _RTE_BUS_H_
+
+/**
+ * @file
+ *
+ * RTE PMD Bus Abstraction interfaces
+ *
+ * This file exposes APIs and Interfaces for Bus Abstraction over the devices
+ * drivers in EAL.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdio.h>
+#include <sys/queue.h>
+
+#include <rte_log.h>
+#include <rte_dev.h>
+
+/** Double linked list of buses */
+TAILQ_HEAD(rte_bus_list, rte_bus);
+
+/**
+ * A structure describing a generic bus.
+ */
+struct rte_bus {
+	TAILQ_ENTRY(rte_bus) next;   /**< Next bus object in linked list */
+	const char *name;            /**< Name of the bus */
+};
+
+/**
+ * Register a Bus handler.
+ *
+ * @param bus
+ *   A pointer to a rte_bus structure describing the bus
+ *   to be registered.
+ */
+void rte_bus_register(struct rte_bus *bus);
+
+/**
+ * Unregister a Bus handler.
+ *
+ * @param bus
+ *   A pointer to a rte_bus structure describing the bus
+ *   to be unregistered.
+ */
+void rte_bus_unregister(struct rte_bus *bus);
+
+/**
+ * Dump information of all the buses registered with EAL.
+ *
+ * @param f
+ *	A valid and open output stream handle
+ *
+ * @return
+ *	 0 in case of success
+ *	!0 in case there is error in opening the output stream
+ */
+void rte_bus_dump(FILE *f);
+
+/** Helper for Bus registration. The constructor has higher priority than
+ * PMD constructors
+ */
+#define RTE_REGISTER_BUS(nm, bus) \
+static void __attribute__((constructor(101), used)) businitfn_ ##nm(void) \
+{\
+	(bus).name = RTE_STR(nm);\
+	rte_bus_register(&bus); \
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _RTE_BUS_H */
diff --git a/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/common/include/rte_dev.h
index b17791f..24c1c00 100644
--- a/lib/librte_eal/common/include/rte_dev.h
+++ b/lib/librte_eal/common/include/rte_dev.h
@@ -122,6 +122,7 @@ struct rte_driver;
  */
 struct rte_device {
 	TAILQ_ENTRY(rte_device) next; /**< Next device */
+	struct rte_bus *bus;          /**< Device connected to this bus */
 	const struct rte_driver *driver;/**< Associated driver */
 	int numa_node;                /**< NUMA node connection */
 	struct rte_devargs *devargs;  /**< Device user arguments */
diff --git a/lib/librte_eal/linuxapp/eal/Makefile b/lib/librte_eal/linuxapp/eal/Makefile
index 4e206f0..aa874a5 100644
--- a/lib/librte_eal/linuxapp/eal/Makefile
+++ b/lib/librte_eal/linuxapp/eal/Makefile
@@ -87,6 +87,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_cpuflags.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_string_fns.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_hexdump.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_devargs.c
+SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_bus.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_dev.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_options.c
 SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_thread.c
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index 83721ba..b553b13 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -178,3 +178,13 @@ DPDK_16.11 {
 	rte_eal_vdrv_unregister;
 
 } DPDK_16.07;
+
+DPDK_17.02 {
+	global:
+
+	rte_bus_list;
+	rte_bus_dump;
+	rte_bus_register;
+	rte_bus_unregister;
+
+} DPDK_16.11;
-- 
2.7.4