[dpdk-dev] [PATCH] scripts: enable extended tag of PCIe

[zhida zang <zhida.zang@intel.com>]

As 'extended tag' of PCIe needs to be enabled for i40e high performance,
Linux command of 'setpci' can be used to check and set the corresponding 
bit of 'extended tag' of PCIe configuration space. The script is to check
and set the right bit in PCIe configuration space to enable 'extended tag'.

Signed-off-by: Zhida Zang <zhida.zang@intel.com>
---
 tools/set_pci.py | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100755 tools/set_pci.py

diff --git a/tools/set_pci.py b/tools/set_pci.py
new file mode 100755
index 0000000..e242efb
--- /dev/null
+++ b/tools/set_pci.py
@@ -0,0 +1,124 @@
+#! /usr/bin/python
+import sys
+import os
+import subprocess
+import getopt
+from os.path import basename
+
+# The register to check if extended tag is supported or not.
+PCI_DEV_CAP_REG = 0xA4
+# The control register which contains the bit to enable/disable 'extended tag'.
+PCI_DEV_CTRL_REG = 0xA8
+# The mask of 'extended tag' in capability register.
+PCI_DEV_CAP_EXT_TAG_MASK = 0x20
+# The mask of 'extended tag' in control register.
+PCI_DEV_CTRL_EXT_TAG_MASK = 0x100
+
+dev_ids = {}
+flag = "Set"
+
+
+def usage():
+    '''Print usage information for the program'''
+    argv0 = basename(sys.argv[0])
+    print """
+Usage:
+------
+
+    %(argv0)s [options] DEVICE1 DEVICE2 ....
+
+where DEVICE1, DEVICE2 etc, are specified via PCI "domain:bus:slot.func" syntax
+or "bus:slot.func" syntax. For devices bound to Linux kernel drivers, they may
+also be referred to by Linux interface name e.g. eth0, eth1, em0, em1, etc.
+
+Options:
+    --help, --usage:
+        Display usage information and quit
+
+    -s --set:
+        Set the following pci device
+
+    -u --Unset:
+        Unset the following pci device
+
+Examples:
+---------
+To set pci 0a:00.0
+        %(argv0)s -s 0a:00.0
+        %(argv0)s --set 0a:00.0
+
+To unset 0000:01:00.0
+        %(argv0)s -u 0000:01:00.0
+        %(argv0)s --unset 0000:01:00.0
+
+To set 0000:02:00.0 and 0000:02:00.1
+        %(argv0)s -s 02:00.0 02:00.1
+
+    """ % locals()  # replace items from local variables
+
+
+def parse_args():
+    global flag
+    global dev_ids
+    if len(sys.argv) <= 1:
+        usage()
+        sys.exit(0)
+    try:
+        opts, dev_ids = getopt.getopt(
+            sys.argv[1:],
+            "su",
+            ["help", "usage", "set", "unset"]
+            )
+    except getopt.GetoptError, error:
+        print str(error)
+        print "Run '%s --usage' for further information" % sys.argv[0]
+        sys.exit(1)
+
+    for opt, arg in opts:
+        if opt == "--help" or opt == "--usage":
+            usage()
+            sys.exit(0)
+        if opt == "-s" or opt == "--set":
+            flag = "Set"
+        if opt == "-u" or opt == "--unset":
+            flag = "Unset"
+
+
+def check_output(args, stderr=None):
+    '''Run a command and capture its output'''
+    return subprocess.Popen(
+        args,
+        stdout=subprocess.PIPE,
+        stderr=stderr
+        ).communicate()[0]
+
+
+def set_pci():
+    if len(dev_ids) == 0:
+        print "Error: No devices specified."
+        print "Run '%s --usage' for further information" % sys.argv[0]
+        sys.exit(1)
+    param_cap = "%x.W" % PCI_DEV_CAP_REG
+    for k in range(len(dev_ids)):
+        val = check_output(["setpci", "-s", dev_ids[k], param_cap])
+        if (not (int(val, 16) & PCI_DEV_CAP_EXT_TAG_MASK)):
+            print dev_ids[k], "Not supported"
+            continue
+        if (int(val, 16) & PCI_DEV_CTRL_EXT_TAG_MASK):
+            continue
+        param_ctrl = "%x.W" % PCI_DEV_CTRL_REG
+        val = check_output(["setpci", "-s", dev_ids[k], param_ctrl])
+        if flag == "Set":
+            val = int(val, 16) | PCI_DEV_CTRL_EXT_TAG_MASK
+        else:
+            val = int(val, 16) & ~PCI_DEV_CTRL_EXT_TAG_MASK
+        param_ctrl = "%x.W=%x" % (PCI_DEV_CTRL_REG, val)
+        check_output(["setpci", "-s", dev_ids[k], param_ctrl])
+
+
+def main():
+    parse_args()
+    set_pci()
+
+if __name__ == "__main__":
+    main()
-- 
1.9.3