67  * Negotiation is a mechanism for moving between modes. Compatibility mode
68  * is a default mode, from which negotiations to other modes occur and
70  * Compatibility mode provides a unidirectional (forward) channel for
73  * Each mode has a number of phases. [Mode, phase] pair represents the
91  * - Compatibility mode: byte-wide forward channel ~50KB/sec;
93  * - Nibble mode: nibble-wide (4-bit) reverse channel ~30KB/sec;
94  * - ECP mode: byte-wide bidirectional channel (~1MB/sec);
99  * State is a combination of 1284 mode {ECPP_*_MODE}, 1284 phase {ECPP_PHASE_*}
104  *   pp->current_mode  -- 1284 mode used for forward transfers;
105  *   pp->backchannel   -- 1284 mode used for backward transfers;
108  * Bidirectional operation in Compatibility mode is provided by a combination:
118  * When opened, driver is in ECPP_IDLE state, current mode is ECPP_CENTRONICS
119  * Default negotiation tries to negotiate to the best mode supported by printer,
161  * This way Nibble and ECP mode backchannel are implemented.
177 int noecp = 0;	/* flag not to use ECP mode */
317 /* IEEE 1284 mode transitions */
454 	ECPP_CENTRONICS		/* supported mode */
611 		 * Initialize the chip and restore current mode if needed
850 	 * peripherals ( Centronics peripherals) will operate in DMA mode.
909 	 * In PIO mode, ecpp_isr() will loop for wait for the busy signal
918 	 * In PIO mode, centronics transfers must hold the data signals
925 	 * In PIO mode, centronics transfers asserts the strobe signal
1080 	 * Get ready: check host/peripheral, negotiate into default mode
1121 	    "ecpp_open: mode=%x, phase=%x ecr=%x, dsr=%x, dcr=%x\n",
1207 	/* set link to Compatible mode */
1525 		pp->xfer_parms.mode = pp->current_mode;
1599 		/* must be in diagnostic mode for these commands to work */
1739 		/* DSR only makes sense in Centronics & Compat mode */
1765 		/* status only makes sense in Centronics & Compat mode */
2135 		if (!((xferp->mode == ECPP_CENTRONICS) ||
2136 		    (xferp->mode == ECPP_COMPAT_MODE) ||
2137 		    (xferp->mode == ECPP_NIBBLE_MODE) ||
2138 		    (xferp->mode == ECPP_ECP_MODE) ||
2139 		    (xferp->mode == ECPP_DIAG_MODE))) {
2147 		ecpp_error(pp->dip, "srvioc: current_mode =%x new mode=%x\n",
2148 		    pp->current_mode, pp->xfer_parms.mode);
2150 		if (ecpp_mode_negotiation(pp, pp->xfer_parms.mode) == FAILURE) {
2154 			 * mode nego was a success.  If nibble mode check
2176 		pp->xfer_parms.mode = pp->current_mode;
2187 		/* must be in diagnostic mode for these commands to work */
2216 		/* must be in diagnostic mode for these commands to work */
2224 			/* put superio into PIO mode */
2234 			/* change to mode 110 */
2253 		/* must be in diagnostic mode for these commands to work */
2292 			id.mode = dp32->mode;
2317 		id.mode = ECPP_NIBBLE_MODE;
2401 	int			mode;
2407 	mode = id->mode;
2410 	if ((mode < ECPP_CENTRONICS) || (mode > ECPP_ECP_MODE)) {
2411 		ecpp_error(pp->dip, "ecpp_srvioc_devid: mode=%x, len=%x\n",
2412 		    mode, id->len);
2417 	/* Currently only Nibble mode is supported */
2418 	if (mode != ECPP_NIBBLE_MODE) {
2429 	if (error = ecpp_getdevid(pp, NULL, &len, mode)) {
2457 	error = ecpp_getdevid(pp, datamp->b_rptr, &len, mode);
2667 	/* in DIAG mode clear TFIFO if needed */
2737 			/* PIO mode */
2748 		/* put superio into TFIFO mode, if not already */
2853 	/* pport must be in PIO mode */
2928 	/* set the right ECR mode and disable DMA */
3105 	 * delay is not needed for PIO mode
3112 	/* on 97317 in Extended mode IRQ_ST of DSR is deasserted when read */
3129 		 * as a result, we can miss a service interrupt in PIO mode
3135 		 * also, nErr interrupt (ECP mode) not always reflected in DCSR
3293 	/* Intr generated while invoking TFIFO mode. Exit */
3409 	ecpp_error(pp->dip, "ecpp_nErr_ihdlr: mode=%x, phase=%x\n",
3447 		ecpp_error(pp->dip, "ecpp_nErr_ihdlr: wrong mode!\n");
3480 		 * Sent next byte in PIO mode
3635 		 * PIO mode timeout
3657 		 * DMA mode timeout
3971  * In Compatibility mode, check if the peripheral is ready to accept data
4122  * Interface initialization, abnormal termination into Compatibility mode
4124  * Peripheral may be non-1284, so we set current mode to ECPP_CENTRONICS
4151  * ECP mode negotiation
4158 	/* ECP mode negotiation */
4189 	/* successful negotiation into ECP mode */
4199  * Nibble mode negotiation
4220 	/* successful negotiation into Nibble mode */
4248  * required mode is indicated by extensibility request value
4251  * current mode is set according to xreq,
4252  * otherwise FAILURE is returned and current mode is set to
4255  * Current phase must be set by the caller (mode-specific negotiation)
4266 	/* negotiation should start in Compatibility mode */
4269 	/* Set host into Compat mode */
4311 	 * For Nibble mode Xflag must be low, otherwise it must be high
4343  * 1284 Termination: Events 22..28 - set link to Compatibility mode
4347  * (in particular, in ECP mode current phase must be Forward Idle)
4353  * current mode is ECPP_CENTRONICS, current phase is ECPP_PHASE_C_IDLE
4368 	/* Set host into Compat mode, interrupts disabled */
4377 	 * EPP mode uses simple nInit pulse for termination
4391 	/* terminate peripheral to Compat mode */
4412 	/* Event 26: the peripheral puts itself in Compatible mode */
4430 	/* Compatible mode Idle Phase */
4563  * implements both backchannel watchdog and transfer timeout in ECP mode
4682  * Read one byte in the Nibble mode
4768 		/* this routine will read the data in Nibble mode */
4838 	/* place port into PS2 mode */
4886 	/* place port into PS2 mode */
4903  * Default negotiation chooses the best mode supported by peripheral
4904  * Note that backchannel mode may be different from forward mode
4925  * Negotiate to the mode indicated by newmode
4930 	/* any other mode is impossible */
4952 		/* put superio into PIO mode */
5023 		 * In DIAG mode application can do nasty things(e.g drive pins)
5024 		 * To keep peripheral sane, terminate to Compatibility mode
5028 		/* put superio into TFIFO mode */
5044 		    "ecpp_mode_negotiation: mode %d not supported\n", newmode);
5051  * the interface in a mode capable of peripheral-to-host data transfer.
5052  * This requires the host periodically to place the interface in such a mode.
5150  * to Compatibility mode and FAILURE is returned
5215  * 'Request Device ID using nibble mode' negotiation
5240 	/* successful negotiation into Nibble mode */
5256  * After 2) port is in Compatible mode
5261 ecpp_getdevid(struct ecppunit *pp, uint8_t *id, int *lenp, int mode)
5267 	switch (mode) {
5270 		if ((pp->current_mode != mode) || (id == NULL)) {
5328 			 * required to return the link to the Compatibility mode
5486 	 * clear bits 3-0 in CTR (aka DCR) prior to enabling ECP mode
5487 	 * CTR5 can not be cleared in SPP mode, CTR5 will return 1.
5495 	/* enable ECP mode, level intr (note that DCR bits 3-0 == 0x0) */
5510 	/* we are in centronic mode */
5513 	/* in compatible mode with no data transfer in progress */
5520  * A new mode was set, do some mode specific reconfiguration
5583 	/* ECP mode */
5633  * A new mode was set, do some mode specific reconfiguration
5890 	/* set FIFO threshold 1 and ECP mode, preserve bit 7 (IRQ polarity) */
5950 	/* set mode to read-from-memory. */
6300 	EK_NAMED_INIT(mode);

Indexes created Tue Jul 24 14:28:13 CEST 2018