PCI Token-Ring High Performance (14101800) Device Driver

Kernel Extensions and Device Support Programming Concepts

PCI Token-Ring High Performance (14101800) Device Driver

The Token-Ring device driver is a dynamically loadable device driver that runs on AIX Version 4.1 (or later). The device driver is automatically loaded into the system at device configuration time as part of the configuration process. The interface to the device is through the kernel services known as Network Services.

Interfacing to the device driver is achieved by calling the device driver's entry points for opening the device, closing the device, transmitting data, doing a remote dump, and issuing device control commands.

The Token-Ring device driver interfaces with the PCI Token-Ring High-Performance Network Adapter (14101800). The adapter is IEEE 802.5 compatible and supports both 4 and 16 megabit per second networks. The adapter supports only an RJ-45 connection.

Configuration Parameters

Ring Speed	The device driver supports a user-configurable parameter that indicates if the token-ring is to run at 4 or 16 megabits per second. The device driver supports a user-configurable parameter that selects the ring speed of the adapter. There are three options for the ring speed: 4, 16, or autosense. If 4 is selected, the device driver opens the adapter with 4 Mbits. It returns an error if the ring speed does not match the network speed. If 16 is selected, the device driver opens the adapter with 16 Mbits. It returns an error if the ring speed does not match the network speed. If autosense is selected, the adapter guarantees a successful open, and the speed used to open is dependent on: If it is opened on an existing network, in which case the speed is the ring speed of the network. If it is opened on a new network, in which case 16 Mbits is used if the adapter is new; or if the adapter successfully opened, the ring speed is the speed of the last successful open.
Receive Queue	The device driver supports a user-configurable receive queue that can be set to store between 32 and 160 receive buffers. These buffers are mbuf clusters into which the device writes the received data.
Software Transmit Queue
	The device driver supports a user-configurable transmit queue that can be set to store between 32 and 2048 transmit request pointers. Each transmit request pointer corresponds to a transmit request that may be for several buffers of data.
Software Priority Transmit Queue
	The device driver supports a user-configurable priority transmit queue that can be set to store between 32 and 160 transmit request pointers. Each transmit request pointer corresponds to a transmit request that may be for several buffers of data.
Full Duplex	Indicates whether the adapter is operating in full-duplex or half-duplex mode. If this field is set yes, the device driver programs the adapter to be in full-duplex mode. The default value is half-duplex.
Attention MAC Frames
	The device driver supports a user-configurable parameter that indicates if attention MAC frames should be received.
Beacon MAC Frames	The device driver supports a user-configurable parameter that indicates if beacon MAC frames should be received.
Priority Data Transmission
	The device driver supports a user option to request priority transmission of the data packets.
Network Address	The driver supports the use of the device's hardware address as the network address or an alternate network address configured through software. When an alternate address is used, any valid Individual Address can be used. The most significant bit of the address must be set to zero.

Device Driver Configuration and Unconfiguration

The tok_config() entry point conforms to the AIX Version 4.1 (or later) kernel object file entry point.

Device Driver Open

The tok_open() function is called to open the specified network device.

The Token-Ring device driver does a synchronous open. The device is initialized at this time. When the resources are successfully allocated, the device starts the process of attaching the device to the network.

If the connection is successful, the NDD_RUNNING flag is set in the ndd_flags field, and an NDD_CONNECTED status block is sent.

If the device connection fails, the NDD_LIMBO flag is set in the ndd_flags field, and an NDD_LIMBO_ENTRY status block is sent.

If the device is eventually connected, the NDD_LIMBO flag is turned off, and the NDD_RUNNING flag is set in the ndd_flags field. Both NDD_CONNECTED and NDD_LIMBO_EXIT status blocks are set.

Device Driver Close

The tok_close() function is called to close the specified network device. This function resets the device to a known state and frees system resources associated with the device.

The device is not detached from the network until the device's transmit queue is allowed to drain.

Data Transmission

The tok_output() function transmits data using the network device.

The device driver does not support mbufs from user memory that have the M_EXT flag set.

If the destination address in the packet is a broadcast address, the M_BCAST flag in the p_mbuf->m_flags field should be set prior to entering this routine. A broadcast address is defined as 0xFFFF FFFF FFFF or 0xC000 FFFF FFFF. If the destination address in the packet is a multicast address, the M_MCAST flag in the p_mbuf->m_flags field should be set prior to entering this routine. A multicast address is defined as a non-individual address other than a broadcast address. The device driver keeps statistics based on the M_BCAST and M_MCAST flags.

If a packet is transmitted with a destination address that matches the adapter's address, the packet is received. This is true for the adapter's physical address, broadcast addresses (0xC000 FFFF FFFF or 0xFFFF FFFF FFFF), enabled functional addresses, or an enabled group address.

Data Reception

When the Token-Ring device driver receives a valid packet from the network device, the Token-Ring device driver calls the nd_receive() function specified in the ndd_t structure of the network device. The nd_receive() function is part of a CDLI network demuxer. The packet is passed to the nd_receive() function in mbufs.

The Token-Ring device driver passes only one packet to the nd_receive() function at a time.

The device driver sets the M_BCAST flag in the p_mbuf->m_flags field when a packet is received that has an all-stations broadcast address. This address is defined as 0xFFFF FFFF FFFF or 0xC000 FFFF FFFF.

The device driver sets the M_MCAST flag in the p_mbuf->m_flags field when a packet is received that has a non-individual address that is different from the all-stations broadcast address.

The adapter does not pass invalid packets to the device driver.

Asynchronous Status

When a status event occurs on the device, the Token-Ring device driver builds the appropriate status block and calls the nd_status() function specified in the ndd_t structure of the network device. The nd_status() function is part of a CDLI network demuxer.

The following status blocks are defined for the Token-Ring device driver.

Hard Failure

When a hard failure occurs on the Token-Ring device, the following status blocks are returned by the Token-Ring device driver. One of these status blocks indicates that a fatal error occurred.

NDD_HARD_FAIL

When a transmit error occurs, it tries to recover. If the error is unrecoverable, this status block is generated.

code	Set to NDD_HARD_FAIL.
option[0]	Set to NDD_HARD_FAIL.
option[ ]	The remainder of the status block can be used to return additional status information.

Enter Network Recovery Mode

When the device driver detects an error that requires initiating recovery logic to make the device temporarily unavailable, the following status block is returned by the device driver.

Note: While the device driver is in this recovery logic, the device may not be fully functional. The device driver notifies users when the device is fully functional by way of an NDD_LIMBO_EXIT asynchronous status block:

code	Set to NDD_LIMBO_ENTER.
option[0]	Set to one of the following: NDD_CMD_FAIL NDD_ADAP_CHECK NDD_TX_ERR NDD_TX_TIMEOUT NDD_AUTO_RMV TOK_ADAP_OPEN TOK_ADAP_INIT TOK_DMA_FAIL TOK_RING_SPEED TOK_RMV_ADAP TOK_WIRE_FAULT
option[ ]	The remainder of the status block can be used to return additional status information by the device driver.

Exit Network Recovery Mode

When the device driver has successfully completed recovery logic from the error that made the device temporarily unavailable, the following status block is returned by the device driver:

Note: The device is now fully functional.

code	Set to NDD_LIMBO_EXIT.
option[ ]	The option fields are not used.

Device Control Operations

The tok_ctl() function is used to provide device control functions.

NDD_GET_STATS

The user should pass in the tok_ndd_stats_t structure as defined in <sys/cdli_tokuser.h>. The driver fails a call with a buffer smaller than the structure.

The structure must be in kernel heap so that the device driver can copy the statistics into it. Also, it must be pinned.

NDD_PROMISCUOUS_ON

Setting promiscuous mode will not cause non-LLC frames to be received by the driver unless the user also enables those filters (Attention MAC frames, Beacon MAC frames).

The driver maintains a counter of requests.

NDD_PROMISCUOUS_OFF

This command releases a request from a user to PROMISCUOUS_ON; it will not exit the mode on the adapter if more requests are outstanding.

NDD_MIB_QUERY

The arg parameter specifies the address of the token_ring_all_mib_t structure. This structure is defined in the /usr/include/sys/tokenring_mibs.h file.

The device driver does not support any variables for read_write or write only. If the syntax of a member of the structure is some integer type, the level of support flag is stored in the whole field, regardless of the size of the field. For those fields that are defined as character arrays, the value is returned only in the first byte in the field.

NDD_MIB_GET

The arg parameter specifies the address of the token_ring_all_mib_t structure. This structure is defined in the /usr/include/sys/tokenring_mibs.h file.

NDD_ENABLE_ADDRESS

This command enables the receipt of packets with a functional or a group address. The functional address indicator (bit 0 "the MSB" of byte 2) indicates whether the address is a functional address (bit 0) or a group address (bit 1). The length field is not used because the address must be 6 bytes in length.

functional address

The specified address is ORed with the currently specified functional addresses, and the resultant address is set as the functional address for the device. Functional addresses are encoded in a bit-significant format, thereby allowing multiple individual groups to be designated by a single address.

The Token-Ring network architecture provides bit-specific functional addresses for widely used functions, such as configuration report server. Ring stations use functional address "masks" to identify these functions. For example, if function G is assigned a functional address of 0xC000 0008 0000, and function M is assigned a function address of 0xC000 0000 0040, then ring station Y, whose node contains function G and M, would have a mask of 0xC000 0008 0040. Ring station Y would receive packets addressed to either function G or M or to an address like 0xC000 0008 0048 since that address contains bits specified in the "mask."

The NDD_ALTADDRS and TOK_RECEIVE_FUNC flags in the ndd_flags field are set.

Since functional addresses are encoded in a bit-significant format, reference counts are kept on each of the 31 least significant bits of the address.

group address

The device supports 256 general group addresses. The promiscuous mode is turned on when the group address to be set is more than 256. The device driver maintains a reference count on this operation.

The device supports 256 general group addresses. The promiscuous mode is turned on when the group address needed to be set are more than 256. The device driver will maintain a reference count on this operation.

The NDD_ALTADDRS and TOK_RECEIVE_GROUP flags in the ndd_flags field are set.

NDD_DISABLE_ADDRESS

This command disables the receipt of packets with a functional or a group address. The functional address indicator (bit 0 "the MSB" of byte 2) indicates whether the address is a functional address (bit 0) or a group address (bit 1). The length field is not used because the address must be 6 bytes in length.

functional address

The reference counts are decremented for those bits in the functional address that are 1 (on). If the reference count for a bit goes to 0, the bit is "turned off" in the functional address for the device.

If no functional addresses are active after receipt of this command, the TOK_RECEIVE_FUNC flag in the ndd_flags field is reset. If no functional or group addresses are active after receipt of this command, the NDD_ALTADDRS flag in the ndd_flags field is reset.

group address

If group address enable is less than 256, the driver sends a command to the device to disable the receipt of the packets with the specified group address. Otherwise, the group address is deleted from the group address table.

If there are less than 256 group addresses enabled after the receipt of this command, the promiscuous mode is turned off.

If no group address is active after receipt of this command, the TOK_RECEIVE_GROUP flag in the ndd_flags field is reset. If no functional or group addresses are active after receipt of this command, the NDD_ALTADDRS flag in the ndd_flags field is reset.

NDD_PRIORITY_ADDRESS

The driver returns the address of the device driver's priority transmit routine.

NDD_MIB_ADDR

The driver returns at least three addresses that are device physical addresses (or alternate addresses specified by the user), two broadcast addresses (0xFFFFFFFFFFFF and 0xC000 FFFF FFFF), and any additional addresses specified by the user, such as functional addresses and group addresses.

NDD_CLEAR_STATS

The counters kept by the device are zeroed.

NDD_GET_ALL_STATS

The arg parameter specifies the address of the mon_all_stats_t structure. This structure is defined in the /usr/include/sys/cdli_tokuser.h file.

The statistics that are returned contain information obtained from the device. If the device is inoperable, the statistics returned are not the current device statistics. The copy of the ndd_flags field can be checked to determine the state of the device.

Reliability, Availability, and Serviceability (RAS)

Trace

The Token-Ring device driver has four trace points. The IDs are defined in the /sys/cdli_tokuser.h file.

Error Logging

The Token-Ring error log templates are:

ERRID_STOK_ADAP_CHECK
	The microcode on the device performs a series of diagnostic checks when the device is idle. These checks can find errors, and they are reported as adapter checks. If the device is connected to the network when this error occurs, the device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_ADAP_OPEN
	Enables the device driver to open the device. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_AUTO_RMV
	An internal hardware error following the beacon automatic removal process was detected. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_RING_SPEED
	The ring speed (or ring data rate) is probably wrong. Contact the network administrator to determine the speed of the ring. The device driver only retries twice at 2-minute intervals after this error log entry is generated.
ERRID_STOK_DMAFAIL	The device detected a DMA error in a TX or RX operation. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required unless the problem persists.
ERRID_STOK_BUS_ERR	The device detected a Micro Channel bus error. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_DUP_ADDR
	The device detected that another station on the ring has a device address that is the same as the device address being tested. Contact the network administrator to determine why.
ERRID_STOK_MEM_ERR	An error occurred while allocating memory or timer control block structures.
ERRID_STOK_RCVRY_EXIT
	The error that caused the device driver to go into error recovery mode was corrected.
ERRID_STOK_RMV_ADAP
	The device received a remove ring station MAC frame indicating that a network management function directed this device to get off the ring. Contact the network administrator to determine why.
ERRID_STOK_WIRE_FAULT
	There is a loose (or bad) cable between the device and the MAU. There is a chance that it might be a bad device. The device driver goes into Network Recover Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_TX_TIMEOUT
	The transmit watchdog timer expired before transmitting a frame. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.
ERRID_STOK_CTL_ERR	The ioctl watchdog timer expired before the device driver received a response from the device. The device driver goes into Network Recovery Mode in an attempt to recover from the error. The device is temporarily unavailable during the recovery procedure. User intervention is not required for this error unless the problem persists.