xref: /kernel/linux/linux-5.10/drivers/usb/serial/io_ionsp.h

/* SPDX-License-Identifier: GPL-2.0+ */
/************************************************************************
 *
 *	IONSP.H		Definitions for I/O Networks Serial Protocol
 *
 *	Copyright (C) 1997-1998 Inside Out Networks, Inc.
 *
 *	These definitions are used by both kernel-mode driver and the
 *	peripheral firmware and MUST be kept in sync.
 *
 ************************************************************************/

/************************************************************************

The data to and from all ports on the peripheral is multiplexed
through a single endpoint pair (EP1 since it supports 64-byte
MaxPacketSize). Therefore, the data, commands, and status for
each port must be preceded by a short header identifying the
destination port. The header also identifies the bytes that follow
as data or as command/status info.

Header format, first byte:

    CLLLLPPP
    --------
    | |	 |------ Port Number:	0-7
    | |--------- Length:	MSB bits of length
    |----------- Data/Command:	0 = Data header
				1 = Cmd / Status (Cmd if OUT, Status if IN)

This gives 2 possible formats:


    Data header:		0LLLLPPP	LLLLLLLL
    ============

    Where (LLLL,LLLLLLL) is 12-bit length of data that follows for
    port number (PPP). The length is 0-based (0-FFF means 0-4095
    bytes). The ~4K limit allows the host driver (which deals in
    transfer requests instead of individual packets) to write a
    large chunk of data in a single request. Note, however, that
    the length must always be <= the current TxCredits for a given
    port due to buffering limitations on the peripheral.


    Cmd/Status header:		1ccccPPP	[ CCCCCCCC,	 Params ]...
    ==================

    Where (cccc) or (cccc,CCCCCCCC) is the cmd or status identifier.
    Frequently-used values are encoded as (cccc), longer ones using
    (cccc,CCCCCCCC). Subsequent bytes are optional parameters and are
    specific to the cmd or status code. This may include a length
    for command and status codes that need variable-length parameters.


In addition, we use another interrupt pipe (endpoint) which the host polls
periodically for flow control information. The peripheral, when there has
been a change, sends the following 10-byte packet:

	RRRRRRRRRRRRRRRR
	T0T0T0T0T0T0T0T0
	T1T1T1T1T1T1T1T1
	T2T2T2T2T2T2T2T2
	T3T3T3T3T3T3T3T3

The first field is the 16-bit RxBytesAvail field, which indicates the
number of bytes which may be read by the host from EP1. This is necessary:
(a) because OSR2.1 has a bug which causes data loss if the peripheral returns
fewer bytes than the host expects to read, and (b) because, on Microsoft
platforms at least, an outstanding read posted on EP1 consumes about 35% of
the CPU just polling the device for data.

The next 4 fields are the 16-bit TxCredits for each port, which indicate how
many bytes the host is allowed to send on EP1 for transmit to a given port.
After an OPEN_PORT command, the Edgeport sends the initial TxCredits for that
port.

All 16-bit fields are sent in little-endian (Intel) format.

************************************************************************/

//
// Define format of InterruptStatus packet returned from the
// Interrupt pipe
//

struct int_status_pkt {
	__u16 RxBytesAvail;			// Additional bytes available to
						// be read from Bulk IN pipe
	__u16 TxCredits[MAX_RS232_PORTS];	// Additional space available in
						// given port's TxBuffer
};


#define GET_INT_STATUS_SIZE(NumPorts) (sizeof(__u16) + (sizeof(__u16) * (NumPorts)))



//
// Define cmd/status header values and macros to extract them.
//
//	Data:		0LLLLPPP LLLLLLLL
//	Cmd/Stat:	1ccccPPP CCCCCCCC

#define	IOSP_DATA_HDR_SIZE		2
#define	IOSP_CMD_HDR_SIZE		2

#define	IOSP_MAX_DATA_LENGTH		0x0FFF		// 12 bits -> 4K

#define	IOSP_PORT_MASK			0x07		// Mask to isolate port number
#define	IOSP_CMD_STAT_BIT		0x80		// If set, this is command/status header

#define IS_CMD_STAT_HDR(Byte1)		((Byte1) & IOSP_CMD_STAT_BIT)
#define IS_DATA_HDR(Byte1)		(!IS_CMD_STAT_HDR(Byte1))

#define	IOSP_GET_HDR_PORT(Byte1)		((__u8) ((Byte1) & IOSP_PORT_MASK))
#define	IOSP_GET_HDR_DATA_LEN(Byte1, Byte2)	((__u16) (((__u16)((Byte1) & 0x78)) << 5) | (Byte2))
#define	IOSP_GET_STATUS_CODE(Byte1)		((__u8) (((Byte1) &  0x78) >> 3))


//
// These macros build the 1st and 2nd bytes for a data header
//
#define	IOSP_BUILD_DATA_HDR1(Port, Len)		((__u8) (((Port) | ((__u8) (((__u16) (Len)) >> 5) & 0x78))))
#define	IOSP_BUILD_DATA_HDR2(Port, Len)		((__u8) (Len))


//
// These macros build the 1st and 2nd bytes for a command header
//
#define	IOSP_BUILD_CMD_HDR1(Port, Cmd)		((__u8) (IOSP_CMD_STAT_BIT | (Port) | ((__u8) ((Cmd) << 3))))


//--------------------------------------------------------------
//
//	Define values for commands and command parameters
//	(sent from Host to Edgeport)
//
//	1ccccPPP P1P1P1P1 [ P2P2P2P2P2 ]...
//
//	cccc:	00-07	2-byte commands. Write UART register 0-7 with
//					value in P1. See 16650.H for definitions of
//					UART register numbers and contents.
//
//		08-0B	3-byte commands:					==== P1 ====	==== P2 ====
//					08	available for expansion
//					09	1-param commands		Command Code	Param
//					0A	available for expansion
//					0B	available for expansion
//
//		0C-0D	4-byte commands.	P1 = extended cmd and P2,P3 = params
//						Currently unimplemented.
//
//		0E-0F	N-byte commands:	P1 = num bytes after P1 (ie, TotalLen - 2)
//						P2 = extended cmd, P3..Pn = parameters.
//						Currently unimplemented.
//

#define	IOSP_WRITE_UART_REG(n)	((n) & 0x07)	// UartReg[ n ] := P1

// Register numbers and contents
// defined in 16554.H.

//					0x08		// Available for expansion.
#define	IOSP_EXT_CMD			0x09		// P1 = Command code (defined below)

// P2 = Parameter

//
// Extended Command values, used with IOSP_EXT_CMD, may
// or may not use parameter P2.
//

#define	IOSP_CMD_OPEN_PORT		0x00		// Enable ints, init UART. (NO PARAM)
#define	IOSP_CMD_CLOSE_PORT		0x01		// Disable ints, flush buffers. (NO PARAM)
#define	IOSP_CMD_CHASE_PORT		0x02		// Wait for Edgeport TX buffers to empty. (NO PARAM)
#define IOSP_CMD_SET_RX_FLOW		0x03		// Set Rx Flow Control in Edgeport
#define IOSP_CMD_SET_TX_FLOW		0x04		// Set Tx Flow Control in Edgeport
#define IOSP_CMD_SET_XON_CHAR		0x05		// Set XON Character in Edgeport
#define IOSP_CMD_SET_XOFF_CHAR		0x06		// Set XOFF Character in Edgeport
#define IOSP_CMD_RX_CHECK_REQ		0x07		// Request Edgeport to insert a Checkpoint into

// the receive data stream (Parameter = 1 byte sequence number)

#define IOSP_CMD_SET_BREAK		0x08		// Turn on the BREAK (LCR bit 6)
#define IOSP_CMD_CLEAR_BREAK		0x09		// Turn off the BREAK (LCR bit 6)


//
// Define macros to simplify building of IOSP cmds
//

#define MAKE_CMD_WRITE_REG(ppBuf, pLen, Port, Reg, Val)			\
do {									\
	(*(ppBuf))[0] = IOSP_BUILD_CMD_HDR1((Port),			\
					    IOSP_WRITE_UART_REG(Reg));	\
	(*(ppBuf))[1] = (Val);						\
									\
	*ppBuf += 2;							\
	*pLen  += 2;							\
} while (0)

#define MAKE_CMD_EXT_CMD(ppBuf, pLen, Port, ExtCmd, Param)		\
do {									\
	(*(ppBuf))[0] = IOSP_BUILD_CMD_HDR1((Port), IOSP_EXT_CMD);	\
	(*(ppBuf))[1] = (ExtCmd);					\
	(*(ppBuf))[2] = (Param);					\
									\
	*ppBuf += 3;							\
	*pLen  += 3;							\
} while (0)



//--------------------------------------------------------------
//
//	Define format of flow control commands
//	(sent from Host to Edgeport)
//
//	11001PPP FlowCmd FlowTypes
//
//	Note that the 'FlowTypes' parameter is a bit mask; that is,
//	more than one flow control type can be active at the same time.
//	FlowTypes = 0 means 'no flow control'.
//

//
//	IOSP_CMD_SET_RX_FLOW
//
//	Tells Edgeport how it can stop incoming UART data
//
//  Example for Port 0
//	P0 = 11001000
//  P1 = IOSP_CMD_SET_RX_FLOW
//  P2 = Bit mask as follows:

#define IOSP_RX_FLOW_RTS		0x01	// Edgeport drops RTS to stop incoming data
#define IOSP_RX_FLOW_DTR		0x02	// Edgeport drops DTR to stop incoming data
#define IOSP_RX_FLOW_DSR_SENSITIVITY	0x04	// Ignores Rx data unless DSR high

// Not currently implemented by firmware.
#define IOSP_RX_FLOW_XON_XOFF		0x08	// Edgeport sends XOFF char to stop incoming data.

// Host must have previously programmed the
// XON/XOFF values with SET_XON/SET_XOFF
// before enabling this bit.

//
//	IOSP_CMD_SET_TX_FLOW
//
//	Tells Edgeport what signal(s) will stop it from transmitting UART data
//
//  Example for Port 0
//	P0 = 11001000
//  P1 = IOSP_CMD_SET_TX_FLOW
//  P2 = Bit mask as follows:

#define IOSP_TX_FLOW_CTS		0x01	// Edgeport stops Tx if CTS low
#define IOSP_TX_FLOW_DSR		0x02	// Edgeport stops Tx if DSR low
#define IOSP_TX_FLOW_DCD		0x04	// Edgeport stops Tx if DCD low
#define IOSP_TX_FLOW_XON_XOFF		0x08	// Edgeport stops Tx upon receiving XOFF char.

// Host must have previously programmed the
// XON/XOFF values with SET_XON/SET_XOFF
// before enabling this bit.
#define IOSP_TX_FLOW_XOFF_CONTINUE	0x10	// If not set, Edgeport stops Tx when

// sending XOFF in order to fix broken
// systems that interpret the next
// received char as XON.
// If set, Edgeport continues Tx
// normally after transmitting XOFF.
// Not currently implemented by firmware.
#define IOSP_TX_TOGGLE_RTS		0x20	// Edgeport drives RTS as a true half-duplex

// Request-to-Send signal: it is raised before
// beginning transmission and lowered after
// the last Tx char leaves the UART.
// Not currently implemented by firmware.

//
//	IOSP_CMD_SET_XON_CHAR
//
//	Sets the character which Edgeport transmits/interprets as XON.
//	Note: This command MUST be sent before sending a SET_RX_FLOW or
//	SET_TX_FLOW with the XON_XOFF bit set.
//
//  Example for Port 0
//	P0 = 11001000
//  P1 = IOSP_CMD_SET_XON_CHAR
//  P2 = 0x11


//
//	IOSP_CMD_SET_XOFF_CHAR
//
//	Sets the character which Edgeport transmits/interprets as XOFF.
//	Note: This command must be sent before sending a SET_RX_FLOW or
//	SET_TX_FLOW with the XON_XOFF bit set.
//
//  Example for Port 0
//	P0 = 11001000
//  P1 = IOSP_CMD_SET_XOFF_CHAR
//  P2 = 0x13


//
//	IOSP_CMD_RX_CHECK_REQ
//
//  This command is used to assist in the implementation of the
//  IOCTL_SERIAL_PURGE Windows IOCTL.
//  This IOSP command tries to place a marker at the end of the RX
//  queue in the Edgeport. If the Edgeport RX queue is full then
//  the Check will be discarded.
//  It is up to the device driver to timeout waiting for the
//  RX_CHECK_RSP.  If a RX_CHECK_RSP is received, the driver is
//	sure that all data has been received from the edgeport and
//	may now purge any internal RX buffers.
//  Note tat the sequence numbers may be used to detect lost
//  CHECK_REQs.

//  Example for Port 0
//	P0 = 11001000
//  P1 = IOSP_CMD_RX_CHECK_REQ
//  P2 = Sequence number


//  Response will be:
//  P1 = IOSP_EXT_RX_CHECK_RSP
//  P2 = Request Sequence number



//--------------------------------------------------------------
//
//	Define values for status and status parameters
//	(received by Host from Edgeport)
//
//	1ssssPPP P1P1P1P1 [ P2P2P2P2P2 ]...
//
//	ssss:	00-07	2-byte status.	ssss identifies which UART register
//					has changed value, and the new value is in P1.
//					Note that the ssss values do not correspond to the
//					16554 register numbers given in 16554.H. Instead,
//					see below for definitions of the ssss numbers
//					used in this status message.
//
//		08-0B	3-byte status:					==== P1 ====	==== P2 ====
//					08	LSR_DATA:		New LSR		Errored byte
//					09	1-param responses	Response Code	Param
//					0A	OPEN_RSP:		InitialMsr	TxBufferSize
//					0B	available for expansion
//
//		0C-0D	4-byte status.	P1 = extended status code and P2,P3 = params
//					Not currently implemented.
//
//		0E-0F	N-byte status:	P1 = num bytes after P1 (ie, TotalLen - 2)
//					P2 = extended status, P3..Pn = parameters.
//					Not currently implemented.
//

/****************************************************
 *	SSSS values for 2-byte status messages (0-8)
 ****************************************************/

#define	IOSP_STATUS_LSR			0x00	// P1 is new value of LSR register.

// Bits defined in 16554.H. Edgeport
// returns this in order to report
// line status errors (overrun,
// parity, framing, break). This form
// is used when a errored receive data
// character was NOT present in the
// UART when the LSR error occurred
// (ie, when LSR bit 0 = 0).

#define	IOSP_STATUS_MSR			0x01	// P1 is new value of MSR register.

// Bits defined in 16554.H. Edgeport
// returns this in order to report
// changes in modem status lines
// (CTS, DSR, RI, CD)
//

//					0x02	// Available for future expansion
//					0x03	//
//					0x04	//
//					0x05	//
//					0x06	//
//					0x07	//


/****************************************************
 *	SSSS values for 3-byte status messages (8-A)
 ****************************************************/

#define	IOSP_STATUS_LSR_DATA		0x08	// P1 is new value of LSR register (same as STATUS_LSR)

// P2 is errored character read from
//    RxFIFO after LSR reported an error.

#define	IOSP_EXT_STATUS			0x09	// P1 is status/response code, param in P2.


// Response Codes (P1 values) for 3-byte status messages

#define	IOSP_EXT_STATUS_CHASE_RSP	0	// Reply to CHASE_PORT cmd. P2 is outcome:
#define	IOSP_EXT_STATUS_CHASE_PASS	0	//	P2 = 0: All Tx data drained successfully
#define	IOSP_EXT_STATUS_CHASE_FAIL	1	//	P2 = 1: Timed out (stuck due to flow

//			control from remote device).

#define	IOSP_EXT_STATUS_RX_CHECK_RSP	1	// Reply to RX_CHECK cmd. P2 is sequence number


#define IOSP_STATUS_OPEN_RSP		0x0A	// Reply to OPEN_PORT cmd.

// P1 is Initial MSR value
// P2 is encoded TxBuffer Size:
//	TxBufferSize = (P2 + 1) * 64

//					0x0B	// Available for future expansion

#define GET_TX_BUFFER_SIZE(P2) (((P2) + 1) * 64)




/****************************************************
 *	SSSS values for 4-byte status messages
 ****************************************************/

#define IOSP_EXT4_STATUS		0x0C	// Extended status code in P1,

// Params in P2, P3
// Currently unimplemented.

//					0x0D	// Currently unused, available.



//
// Macros to parse status messages
//

#define	IOSP_GET_STATUS_LEN(code)	((code) < 8 ? 2 : ((code) < 0x0A ? 3 : 4))

#define	IOSP_STATUS_IS_2BYTE(code)	((code) < 0x08)
#define	IOSP_STATUS_IS_3BYTE(code)	(((code) >= 0x08) && ((code) <= 0x0B))
#define	IOSP_STATUS_IS_4BYTE(code)	(((code) >= 0x0C) && ((code) <= 0x0D))