[dpdk-dev] [PATCH v4 13/25] raw/ioat: include example configuration script

[Bruce Richardson <bruce.richardson@intel.com>]

Devices managed by the idxd kernel driver must be configured for DPDK use
before it can be used by the ioat driver. This example script serves both
as a quick way to get the driver set up with a simple configuration, and as
the basis for users to modify it and create their own configuration
scripts.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Kevin Laatz <kevin.laatz@intel.com>
---
 doc/guides/rawdevs/ioat.rst       |  2 +
 drivers/raw/ioat/dpdk_idxd_cfg.py | 79 +++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100755 drivers/raw/ioat/dpdk_idxd_cfg.py

diff --git a/doc/guides/rawdevs/ioat.rst b/doc/guides/rawdevs/ioat.rst
index 5b8d27980e..7c2a2d4570 100644
--- a/doc/guides/rawdevs/ioat.rst
+++ b/doc/guides/rawdevs/ioat.rst
@@ -50,6 +50,8 @@ The `accel-config <https://github.com/intel/idxd-config>`_ utility library can b
 
 .. note::
         The device configuration can also be done by directly interacting with the sysfs nodes.
+        An example of how this may be done can be seen in the script ``dpdk_idxd_cfg.py``
+        included in the driver source directory.
 
 There are some mandatory configuration steps before being able to use a device with an application.
 The internal engines, which do the copies or other operations,
diff --git a/drivers/raw/ioat/dpdk_idxd_cfg.py b/drivers/raw/ioat/dpdk_idxd_cfg.py
new file mode 100755
index 0000000000..bce4bb5bd4
--- /dev/null
+++ b/drivers/raw/ioat/dpdk_idxd_cfg.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright(c) 2020 Intel Corporation
+
+"""
+Configure an entire Intel DSA instance, using idxd kernel driver, for DPDK use
+"""
+
+import sys
+import argparse
+import os
+import os.path
+
+
+class SysfsDir:
+    "Used to read/write paths in a sysfs directory"
+    def __init__(self, path):
+        self.path = path
+
+    def read_int(self, filename):
+        "Return a value from sysfs file"
+        with open(os.path.join(self.path, filename)) as f:
+            return int(f.readline())
+
+    def write_values(self, values):
+        "write dictionary, where key is filename and value is value to write"
+        for filename, contents in values.items():
+            with open(os.path.join(self.path, filename), "w") as f:
+                f.write(str(contents))
+
+
+def configure_dsa(dsa_id, queues):
+    "Configure the DSA instance with appropriate number of queues"
+    dsa_dir = SysfsDir(f"/sys/bus/dsa/devices/dsa{dsa_id}")
+    drv_dir = SysfsDir("/sys/bus/dsa/drivers/dsa")
+
+    max_groups = dsa_dir.read_int("max_groups")
+    max_engines = dsa_dir.read_int("max_engines")
+    max_queues = dsa_dir.read_int("max_work_queues")
+    max_tokens = dsa_dir.read_int("max_tokens")
+
+    # we want one engine per group
+    nb_groups = min(max_engines, max_groups)
+    for grp in range(nb_groups):
+        dsa_dir.write_values({f"engine{dsa_id}.{grp}/group_id": grp})
+
+    nb_queues = min(queues, max_queues)
+    if queues > nb_queues:
+        print(f"Setting number of queues to max supported value: {max_queues}")
+
+    # configure each queue
+    for q in range(nb_queues):
+        wq_dir = SysfsDir(os.path.join(dsa_dir.path, f"wq{dsa_id}.{q}"))
+        wq_dir.write_values({"group_id": q % nb_groups,
+                             "type": "user",
+                             "mode": "dedicated",
+                             "name": f"dpdk_wq{dsa_id}.{q}",
+                             "priority": 1,
+                             "size": int(max_tokens / nb_queues)})
+
+    # enable device and then queues
+    drv_dir.write_values({"bind": f"dsa{dsa_id}"})
+    for q in range(nb_queues):
+        drv_dir.write_values({"bind": f"wq{dsa_id}.{q}"})
+
+
+def main(args):
+    "Main function, does arg parsing and calls config function"
+    arg_p = argparse.ArgumentParser(
+        description="Configure whole DSA device instance for DPDK use")
+    arg_p.add_argument('dsa_id', type=int, help="DSA instance number")
+    arg_p.add_argument('-q', metavar='queues', type=int, default=255,
+                       help="Number of queues to set up")
+    parsed_args = arg_p.parse_args(args[1:])
+    configure_dsa(parsed_args.dsa_id, parsed_args.q)
+
+
+if __name__ == "__main__":
+    main(sys.argv)
-- 
2.25.1