[openib-general] [PATCH][RFC/v1][11/12] Add InfiniBand Documentation files
Roland Dreier
roland at topspin.com
Mon Nov 22 07:14:22 PST 2004
Add files to Documentation/infiniband that describe the tree under
/sys/class/infiniband, the IPoIB driver and the userspace MAD access driver.
Signed-off-by: Roland Dreier <roland at topspin.com>
Index: linux-bk/Documentation/infiniband/ipoib.txt
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-bk/Documentation/infiniband/ipoib.txt 2004-11-21 21:25:58.205565918 -0800
@@ -0,0 +1,55 @@
+IP OVER INFINIBAND
+
+ The ib_ipoib driver is an implementation of the IP over InfiniBand
+ protocol as specified by the latest Internet-Drafts issued by the
+ IETF ipoib working group. It is a "native" implementation in the
+ sense of setting the interface type to ARPHRD_INFINIBAND and the
+ hardware address length to 20 (earlier proprietary implementations
+ masqueraded to the kernel as ethernet interfaces).
+
+Partitions and P_Keys
+
+ When the IPoIB driver is loaded, it creates one interface for each
+ port using the P_Key at index 0. To create an interface with a
+ different P_Key, write the desired P_Key into the main interface's
+ /sys/class/net/<intf name>/create_child file. For example:
+
+ echo 0x8001 > /sys/class/net/ib0/create_child
+
+ This will create an interface named ib0.8001 with P_Key 0x8001. To
+ remove a subinterface, use the "delete_child" file:
+
+ echo 0x8001 > /sys/class/net/ib0/delete_child
+
+ The P_Key for any interface is given by the "pkey" file, and the
+ main interface for a subinterface is in "parent."
+
+Debugging Information
+
+ By compiling the IPoIB driver with CONFIG_INFINIBAND_IPOIB_DEBUG set
+ to 'y', tracing messages are compiled into the driver. They are
+ turned on by setting the module parameters debug_level and
+ mcast_debug_level to 1. These parameters can be controlled at
+ runtime through files in /sys/module/ib_ipoib/.
+
+ CONFIG_INFINIBAND_IPOIB_DEBUG also enables the "ipoib_debugfs"
+ virtual filesystem. By mounting this filesystem, for example with
+
+ mkdir -p /ipoib_debugfs
+ mount -t ipoib_debugfs none /ipoib_debufs
+
+ it is possible to get statistics about multicast groups from the
+ files /ipoib_debugfs/ib0_mcg and so on.
+
+ The performance impact of this option is negligible, so it
+ is safe to enable this option with debug_level set to 0 for normal
+ operation.
+
+ CONFIG_INFINIBAND_IPOIB_DEBUG_DATA enables even more debug output
+ in the data path when debug_level is set to 2. However, even with
+ the output disabled, this option will affect performance.
+
+References
+
+ IETF IP over InfiniBand (ipoib) Working Group
+ http://ietf.org/html.charters/ipoib-charter.html
Index: linux-bk/Documentation/infiniband/sysfs.txt
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-bk/Documentation/infiniband/sysfs.txt 2004-11-21 21:25:58.231562062 -0800
@@ -0,0 +1,63 @@
+SYSFS FILES
+
+ For each InfiniBand device, the InfiniBand drivers create the
+ following files under /sys/class/infiniband/<device name>:
+
+ node_guid - Node GUID
+ sys_image_guid - System image GUID
+
+ In addition, there is a "ports" subdirectory, with one subdirectory
+ for each port. For example, if mthca0 is a 2-port HCA, there will
+ be two directories:
+
+ /sys/class/infiniband/mthca0/ports/1
+ /sys/class/infiniband/mthca0/ports/2
+
+ (A switch will only have a single "0" subdirectory for switch port
+ 0; no subdirectory is created for normal switch ports)
+
+ In each port subdirectory, the following files are created:
+
+ cap_mask - Port capability mask
+ lid - Port LID
+ lid_mask_count - Port LID mask count
+ sm_lid - Subnet manager LID for port's subnet
+ sm_sl - Subnet manager SL for port's subnet
+ state - Port state (DOWN, INIT, ARMED, ACTIVE or ACTIVE_DEFER)
+
+ There is also a "counters" subdirectory, with files
+
+ VL15_dropped
+ excessive_buffer_overrun_errors
+ link_downed
+ link_error_recovery
+ local_link_integrity_errors
+ port_rcv_constraint_errors
+ port_rcv_data
+ port_rcv_errors
+ port_rcv_packets
+ port_rcv_remote_physical_errors
+ port_rcv_switch_relay_errors
+ port_xmit_constraint_errors
+ port_xmit_data
+ port_xmit_discards
+ port_xmit_packets
+ symbol_error
+
+ Each of these files contains the corresponding value from the port's
+ Performance Management PortCounters attribute, as described in
+ section 16.1.3.5 of the InfiniBand Architecture Specification.
+
+ The "pkeys" and "gids" subdirectories contain one file for each
+ entry in the port's P_Key or GID table respectively. For example,
+ ports/1/pkeys/10 contains the value at index 10 in port 1's P_Key
+ table.
+
+MTHCA
+
+ The Mellanox HCA driver also creates the files:
+
+ hw_rev - Hardware revision number
+ fw_ver - Firmware version
+ hca_type - HCA type: "MT23108", "MT25208 (MT23108 compat mode)",
+ or "MT25208"
Index: linux-bk/Documentation/infiniband/user_mad.txt
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-bk/Documentation/infiniband/user_mad.txt 2004-11-21 21:25:58.258558058 -0800
@@ -0,0 +1,77 @@
+USERSPACE MAD ACCESS
+
+Device files
+
+ Each port of each InfiniBand device has a "umad" device attached.
+ For example, a two-port HCA will have two devices, while a switch
+ will have one device (for switch port 0).
+
+Creating MAD agents
+
+ A MAD agent can be created by filling in a struct ib_user_mad_reg_req
+ and then calling the IB_USER_MAD_REGISTER_AGENT ioctl on a file
+ descriptor for the appropriate device file. If the registration
+ request succeeds, a 32-bit id will be returned in the structure.
+ For example:
+
+ struct ib_user_mad_reg_req req = { /* ... */ };
+ ret = ioctl(fd, IB_USER_MAD_REGISTER_AGENT, (char *) &req);
+ if (!ret)
+ my_agent = req.id;
+ else
+ perror("agent register");
+
+ Agents can be unregistered with the IB_USER_MAD_UNREGISTER_AGENT
+ ioctl. Also, all agents registered through a file descriptor will
+ be unregistered when the descriptor is closed.
+
+Receiving MADs
+
+ MADs are received using read(). The buffer passed to read() must be
+ large enough to hold at least one struct ib_user_mad. For example:
+
+ struct ib_user_mad mad;
+ ret = read(fd, &mad, sizeof mad);
+ if (ret != sizeof mad)
+ perror("read");
+
+ In addition to the actual MAD contents, the other struct ib_user_mad
+ fields will be filled in with information on the received MAD. For
+ example, the remote LID will be in mad.lid.
+
+ If a send times out, a receive will be generated with mad.status set
+ to ETIMEDOUT. Otherwise when a MAD has been successfully received,
+ mad.status will be 0.
+
+ poll()/select() may be used to wait until a MAD can be read.
+
+Sending MADs
+
+ MADs are sent using write(). The agent ID for sending should be
+ filled into the id field of the MAD, the destination LID should be
+ filled into the lid field, and so on. For example:
+
+ struct ib_user_mad mad;
+
+ /* fill in mad.data */
+
+ mad.id = my_agent; /* req.id from agent registration */
+ mad.lid = my_dest; /* in network byte order... */
+ /* etc. */
+
+ ret = write(fd, &mad, sizeof mad);
+ if (ret != sizeof mad)
+ perror("write");
+
+/dev files
+
+ To create the appropriate character device files automatically with
+ udev, a rule like
+
+ KERNEL="umad*", NAME="infiniband/%s{ibdev}/ports/%s{port}/mad"
+
+ can be used. This will create a device node named
+
+ /dev/infiniband/mthca0/ports/1/mad
+
+ for port 1 of device mthca0, and so on.
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