xref: /openbmc/linux/drivers/net/ethernet/realtek/atp.c (revision 275876e2)
1 /* atp.c: Attached (pocket) ethernet adapter driver for linux. */
2 /*
3 	This is a driver for commonly OEM pocket (parallel port)
4 	ethernet adapters based on the Realtek RTL8002 and RTL8012 chips.
5 
6 	Written 1993-2000 by Donald Becker.
7 
8 	This software may be used and distributed according to the terms of
9 	the GNU General Public License (GPL), incorporated herein by reference.
10 	Drivers based on or derived from this code fall under the GPL and must
11 	retain the authorship, copyright and license notice.  This file is not
12 	a complete program and may only be used when the entire operating
13 	system is licensed under the GPL.
14 
15 	Copyright 1993 United States Government as represented by the Director,
16 	National Security Agency.  Copyright 1994-2000 retained by the original
17 	author, Donald Becker. The timer-based reset code was supplied in 1995
18 	by Bill Carlson, wwc@super.org.
19 
20 	The author may be reached as becker@scyld.com, or C/O
21 	Scyld Computing Corporation
22 	410 Severn Ave., Suite 210
23 	Annapolis MD 21403
24 
25 	Support information and updates available at
26 	http://www.scyld.com/network/atp.html
27 
28 
29 	Modular support/softnet added by Alan Cox.
30 	_bit abuse fixed up by Alan Cox
31 
32 */
33 
34 static const char version[] =
35 "atp.c:v1.09=ac 2002/10/01 Donald Becker <becker@scyld.com>\n";
36 
37 /* The user-configurable values.
38    These may be modified when a driver module is loaded.*/
39 
40 static int debug = 1; 			/* 1 normal messages, 0 quiet .. 7 verbose. */
41 #define net_debug debug
42 
43 /* Maximum events (Rx packets, etc.) to handle at each interrupt. */
44 static int max_interrupt_work = 15;
45 
46 #define NUM_UNITS 2
47 /* The standard set of ISA module parameters. */
48 static int io[NUM_UNITS];
49 static int irq[NUM_UNITS];
50 static int xcvr[NUM_UNITS]; 			/* The data transfer mode. */
51 
52 /* Operational parameters that are set at compile time. */
53 
54 /* Time in jiffies before concluding the transmitter is hung. */
55 #define TX_TIMEOUT  (400*HZ/1000)
56 
57 /*
58 	This file is a device driver for the RealTek (aka AT-Lan-Tec) pocket
59 	ethernet adapter.  This is a common low-cost OEM pocket ethernet
60 	adapter, sold under many names.
61 
62   Sources:
63 	This driver was written from the packet driver assembly code provided by
64 	Vincent Bono of AT-Lan-Tec.	 Ever try to figure out how a complicated
65 	device works just from the assembly code?  It ain't pretty.  The following
66 	description is written based on guesses and writing lots of special-purpose
67 	code to test my theorized operation.
68 
69 	In 1997 Realtek made available the documentation for the second generation
70 	RTL8012 chip, which has lead to several driver improvements.
71 	  http://www.realtek.com.tw/
72 
73 					Theory of Operation
74 
75 	The RTL8002 adapter seems to be built around a custom spin of the SEEQ
76 	controller core.  It probably has a 16K or 64K internal packet buffer, of
77 	which the first 4K is devoted to transmit and the rest to receive.
78 	The controller maintains the queue of received packet and the packet buffer
79 	access pointer internally, with only 'reset to beginning' and 'skip to next
80 	packet' commands visible.  The transmit packet queue holds two (or more?)
81 	packets: both 'retransmit this packet' (due to collision) and 'transmit next
82 	packet' commands must be started by hand.
83 
84 	The station address is stored in a standard bit-serial EEPROM which must be
85 	read (ughh) by the device driver.  (Provisions have been made for
86 	substituting a 74S288 PROM, but I haven't gotten reports of any models
87 	using it.)  Unlike built-in devices, a pocket adapter can temporarily lose
88 	power without indication to the device driver.  The major effect is that
89 	the station address, receive filter (promiscuous, etc.) and transceiver
90 	must be reset.
91 
92 	The controller itself has 16 registers, some of which use only the lower
93 	bits.  The registers are read and written 4 bits at a time.  The four bit
94 	register address is presented on the data lines along with a few additional
95 	timing and control bits.  The data is then read from status port or written
96 	to the data port.
97 
98 	Correction: the controller has two banks of 16 registers.  The second
99 	bank contains only the multicast filter table (now used) and the EEPROM
100 	access registers.
101 
102 	Since the bulk data transfer of the actual packets through the slow
103 	parallel port dominates the driver's running time, four distinct data
104 	(non-register) transfer modes are provided by the adapter, two in each
105 	direction.  In the first mode timing for the nibble transfers is
106 	provided through the data port.  In the second mode the same timing is
107 	provided through the control port.  In either case the data is read from
108 	the status port and written to the data port, just as it is accessing
109 	registers.
110 
111 	In addition to the basic data transfer methods, several more are modes are
112 	created by adding some delay by doing multiple reads of the data to allow
113 	it to stabilize.  This delay seems to be needed on most machines.
114 
115 	The data transfer mode is stored in the 'dev->if_port' field.  Its default
116 	value is '4'.  It may be overridden at boot-time using the third parameter
117 	to the "ether=..." initialization.
118 
119 	The header file <atp.h> provides inline functions that encapsulate the
120 	register and data access methods.  These functions are hand-tuned to
121 	generate reasonable object code.  This header file also documents my
122 	interpretations of the device registers.
123 */
124 
125 #include <linux/kernel.h>
126 #include <linux/module.h>
127 #include <linux/types.h>
128 #include <linux/fcntl.h>
129 #include <linux/interrupt.h>
130 #include <linux/ioport.h>
131 #include <linux/in.h>
132 #include <linux/string.h>
133 #include <linux/errno.h>
134 #include <linux/init.h>
135 #include <linux/crc32.h>
136 #include <linux/netdevice.h>
137 #include <linux/etherdevice.h>
138 #include <linux/skbuff.h>
139 #include <linux/spinlock.h>
140 #include <linux/delay.h>
141 #include <linux/bitops.h>
142 
143 #include <asm/io.h>
144 #include <asm/dma.h>
145 
146 #include "atp.h"
147 
148 MODULE_AUTHOR("Donald Becker <becker@scyld.com>");
149 MODULE_DESCRIPTION("RealTek RTL8002/8012 parallel port Ethernet driver");
150 MODULE_LICENSE("GPL");
151 
152 module_param(max_interrupt_work, int, 0);
153 module_param(debug, int, 0);
154 module_param_array(io, int, NULL, 0);
155 module_param_array(irq, int, NULL, 0);
156 module_param_array(xcvr, int, NULL, 0);
157 MODULE_PARM_DESC(max_interrupt_work, "ATP maximum events handled per interrupt");
158 MODULE_PARM_DESC(debug, "ATP debug level (0-7)");
159 MODULE_PARM_DESC(io, "ATP I/O base address(es)");
160 MODULE_PARM_DESC(irq, "ATP IRQ number(s)");
161 MODULE_PARM_DESC(xcvr, "ATP transceiver(s) (0=internal, 1=external)");
162 
163 /* The number of low I/O ports used by the ethercard. */
164 #define ETHERCARD_TOTAL_SIZE	3
165 
166 /* Sequence to switch an 8012 from printer mux to ethernet mode. */
167 static char mux_8012[] = { 0xff, 0xf7, 0xff, 0xfb, 0xf3, 0xfb, 0xff, 0xf7,};
168 
169 struct net_local {
170     spinlock_t lock;
171     struct net_device *next_module;
172     struct timer_list timer;	/* Media selection timer. */
173     long last_rx_time;		/* Last Rx, in jiffies, to handle Rx hang. */
174     int saved_tx_size;
175     unsigned int tx_unit_busy:1;
176     unsigned char re_tx,	/* Number of packet retransmissions. */
177 		addr_mode,		/* Current Rx filter e.g. promiscuous, etc. */
178 		pac_cnt_in_tx_buf;
179 };
180 
181 /* This code, written by wwc@super.org, resets the adapter every
182    TIMED_CHECKER ticks.  This recovers from an unknown error which
183    hangs the device. */
184 #define TIMED_CHECKER (HZ/4)
185 #ifdef TIMED_CHECKER
186 #include <linux/timer.h>
187 static void atp_timed_checker(unsigned long ignored);
188 #endif
189 
190 /* Index to functions, as function prototypes. */
191 
192 static int atp_probe1(long ioaddr);
193 static void get_node_ID(struct net_device *dev);
194 static unsigned short eeprom_op(long ioaddr, unsigned int cmd);
195 static int net_open(struct net_device *dev);
196 static void hardware_init(struct net_device *dev);
197 static void write_packet(long ioaddr, int length, unsigned char *packet, int pad, int mode);
198 static void trigger_send(long ioaddr, int length);
199 static netdev_tx_t atp_send_packet(struct sk_buff *skb,
200 				   struct net_device *dev);
201 static irqreturn_t atp_interrupt(int irq, void *dev_id);
202 static void net_rx(struct net_device *dev);
203 static void read_block(long ioaddr, int length, unsigned char *buffer, int data_mode);
204 static int net_close(struct net_device *dev);
205 static void set_rx_mode(struct net_device *dev);
206 static void tx_timeout(struct net_device *dev);
207 
208 
209 /* A list of all installed ATP devices, for removing the driver module. */
210 static struct net_device *root_atp_dev;
211 
212 /* Check for a network adapter of this type, and return '0' iff one exists.
213    If dev->base_addr == 0, probe all likely locations.
214    If dev->base_addr == 1, always return failure.
215    If dev->base_addr == 2, allocate space for the device and return success
216    (detachable devices only).
217 
218    FIXME: we should use the parport layer for this
219    */
220 static int __init atp_init(void)
221 {
222 	int *port, ports[] = {0x378, 0x278, 0x3bc, 0};
223 	int base_addr = io[0];
224 
225 	if (base_addr > 0x1ff)		/* Check a single specified location. */
226 		return atp_probe1(base_addr);
227 	else if (base_addr == 1)	/* Don't probe at all. */
228 		return -ENXIO;
229 
230 	for (port = ports; *port; port++) {
231 		long ioaddr = *port;
232 		outb(0x57, ioaddr + PAR_DATA);
233 		if (inb(ioaddr + PAR_DATA) != 0x57)
234 			continue;
235 		if (atp_probe1(ioaddr) == 0)
236 			return 0;
237 	}
238 
239 	return -ENODEV;
240 }
241 
242 static const struct net_device_ops atp_netdev_ops = {
243 	.ndo_open		= net_open,
244 	.ndo_stop		= net_close,
245 	.ndo_start_xmit		= atp_send_packet,
246 	.ndo_set_rx_mode	= set_rx_mode,
247 	.ndo_tx_timeout		= tx_timeout,
248 	.ndo_change_mtu		= eth_change_mtu,
249 	.ndo_set_mac_address 	= eth_mac_addr,
250 	.ndo_validate_addr	= eth_validate_addr,
251 };
252 
253 static int __init atp_probe1(long ioaddr)
254 {
255 	struct net_device *dev = NULL;
256 	struct net_local *lp;
257 	int saved_ctrl_reg, status, i;
258 	int res;
259 
260 	outb(0xff, ioaddr + PAR_DATA);
261 	/* Save the original value of the Control register, in case we guessed
262 	   wrong. */
263 	saved_ctrl_reg = inb(ioaddr + PAR_CONTROL);
264 	if (net_debug > 3)
265 		printk("atp: Control register was %#2.2x.\n", saved_ctrl_reg);
266 	/* IRQEN=0, SLCTB=high INITB=high, AUTOFDB=high, STBB=high. */
267 	outb(0x04, ioaddr + PAR_CONTROL);
268 #ifndef final_version
269 	if (net_debug > 3) {
270 		/* Turn off the printer multiplexer on the 8012. */
271 		for (i = 0; i < 8; i++)
272 			outb(mux_8012[i], ioaddr + PAR_DATA);
273 		write_reg(ioaddr, MODSEL, 0x00);
274 		printk("atp: Registers are ");
275 		for (i = 0; i < 32; i++)
276 			printk(" %2.2x", read_nibble(ioaddr, i));
277 		printk(".\n");
278 	}
279 #endif
280 	/* Turn off the printer multiplexer on the 8012. */
281 	for (i = 0; i < 8; i++)
282 		outb(mux_8012[i], ioaddr + PAR_DATA);
283 	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
284 	/* udelay() here? */
285 	status = read_nibble(ioaddr, CMR1);
286 
287 	if (net_debug > 3) {
288 		printk(KERN_DEBUG "atp: Status nibble was %#2.2x..", status);
289 		for (i = 0; i < 32; i++)
290 			printk(" %2.2x", read_nibble(ioaddr, i));
291 		printk("\n");
292 	}
293 
294 	if ((status & 0x78) != 0x08) {
295 		/* The pocket adapter probe failed, restore the control register. */
296 		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
297 		return -ENODEV;
298 	}
299 	status = read_nibble(ioaddr, CMR2_h);
300 	if ((status & 0x78) != 0x10) {
301 		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
302 		return -ENODEV;
303 	}
304 
305 	dev = alloc_etherdev(sizeof(struct net_local));
306 	if (!dev)
307 		return -ENOMEM;
308 
309 	/* Find the IRQ used by triggering an interrupt. */
310 	write_reg_byte(ioaddr, CMR2, 0x01);			/* No accept mode, IRQ out. */
311 	write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);	/* Enable Tx and Rx. */
312 
313 	/* Omit autoIRQ routine for now. Use "table lookup" instead.  Uhgggh. */
314 	if (irq[0])
315 		dev->irq = irq[0];
316 	else if (ioaddr == 0x378)
317 		dev->irq = 7;
318 	else
319 		dev->irq = 5;
320 	write_reg_high(ioaddr, CMR1, CMR1h_TxRxOFF); /* Disable Tx and Rx units. */
321 	write_reg(ioaddr, CMR2, CMR2_NULL);
322 
323 	dev->base_addr = ioaddr;
324 
325 	/* Read the station address PROM.  */
326 	get_node_ID(dev);
327 
328 #ifndef MODULE
329 	if (net_debug)
330 		printk(KERN_INFO "%s", version);
331 #endif
332 
333 	printk(KERN_NOTICE "%s: Pocket adapter found at %#3lx, IRQ %d, "
334 	       "SAPROM %pM.\n",
335 	       dev->name, dev->base_addr, dev->irq, dev->dev_addr);
336 
337 	/* Reset the ethernet hardware and activate the printer pass-through. */
338 	write_reg_high(ioaddr, CMR1, CMR1h_RESET | CMR1h_MUX);
339 
340 	lp = netdev_priv(dev);
341 	lp->addr_mode = CMR2h_Normal;
342 	spin_lock_init(&lp->lock);
343 
344 	/* For the ATP adapter the "if_port" is really the data transfer mode. */
345 	if (xcvr[0])
346 		dev->if_port = xcvr[0];
347 	else
348 		dev->if_port = (dev->mem_start & 0xf) ? (dev->mem_start & 0x7) : 4;
349 	if (dev->mem_end & 0xf)
350 		net_debug = dev->mem_end & 7;
351 
352 	dev->netdev_ops 	= &atp_netdev_ops;
353 	dev->watchdog_timeo	= TX_TIMEOUT;
354 
355 	res = register_netdev(dev);
356 	if (res) {
357 		free_netdev(dev);
358 		return res;
359 	}
360 
361 	lp->next_module = root_atp_dev;
362 	root_atp_dev = dev;
363 
364 	return 0;
365 }
366 
367 /* Read the station address PROM, usually a word-wide EEPROM. */
368 static void __init get_node_ID(struct net_device *dev)
369 {
370 	long ioaddr = dev->base_addr;
371 	int sa_offset = 0;
372 	int i;
373 
374 	write_reg(ioaddr, CMR2, CMR2_EEPROM);	  /* Point to the EEPROM control registers. */
375 
376 	/* Some adapters have the station address at offset 15 instead of offset
377 	   zero.  Check for it, and fix it if needed. */
378 	if (eeprom_op(ioaddr, EE_READ(0)) == 0xffff)
379 		sa_offset = 15;
380 
381 	for (i = 0; i < 3; i++)
382 		((__be16 *)dev->dev_addr)[i] =
383 			cpu_to_be16(eeprom_op(ioaddr, EE_READ(sa_offset + i)));
384 
385 	write_reg(ioaddr, CMR2, CMR2_NULL);
386 }
387 
388 /*
389   An EEPROM read command starts by shifting out 0x60+address, and then
390   shifting in the serial data. See the NatSemi databook for details.
391  *		   ________________
392  * CS : __|
393  *			   ___	   ___
394  * CLK: ______|	  |___|	  |
395  *		 __ _______ _______
396  * DI :	 __X_______X_______X
397  * DO :	 _________X_______X
398  */
399 
400 static unsigned short __init eeprom_op(long ioaddr, u32 cmd)
401 {
402 	unsigned eedata_out = 0;
403 	int num_bits = EE_CMD_SIZE;
404 
405 	while (--num_bits >= 0) {
406 		char outval = (cmd & (1<<num_bits)) ? EE_DATA_WRITE : 0;
407 		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_LOW);
408 		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_HIGH);
409 		eedata_out <<= 1;
410 		if (read_nibble(ioaddr, PROM_DATA) & EE_DATA_READ)
411 			eedata_out++;
412 	}
413 	write_reg_high(ioaddr, PROM_CMD, EE_CLK_LOW & ~EE_CS);
414 	return eedata_out;
415 }
416 
417 
418 /* Open/initialize the board.  This is called (in the current kernel)
419    sometime after booting when the 'ifconfig' program is run.
420 
421    This routine sets everything up anew at each open, even
422    registers that "should" only need to be set once at boot, so that
423    there is non-reboot way to recover if something goes wrong.
424 
425    This is an attachable device: if there is no private entry then it wasn't
426    probed for at boot-time, and we need to probe for it again.
427    */
428 static int net_open(struct net_device *dev)
429 {
430 	struct net_local *lp = netdev_priv(dev);
431 	int ret;
432 
433 	/* The interrupt line is turned off (tri-stated) when the device isn't in
434 	   use.  That's especially important for "attached" interfaces where the
435 	   port or interrupt may be shared. */
436 	ret = request_irq(dev->irq, atp_interrupt, 0, dev->name, dev);
437 	if (ret)
438 		return ret;
439 
440 	hardware_init(dev);
441 
442 	init_timer(&lp->timer);
443 	lp->timer.expires = jiffies + TIMED_CHECKER;
444 	lp->timer.data = (unsigned long)dev;
445 	lp->timer.function = atp_timed_checker;    /* timer handler */
446 	add_timer(&lp->timer);
447 
448 	netif_start_queue(dev);
449 	return 0;
450 }
451 
452 /* This routine resets the hardware.  We initialize everything, assuming that
453    the hardware may have been temporarily detached. */
454 static void hardware_init(struct net_device *dev)
455 {
456 	struct net_local *lp = netdev_priv(dev);
457 	long ioaddr = dev->base_addr;
458     int i;
459 
460 	/* Turn off the printer multiplexer on the 8012. */
461 	for (i = 0; i < 8; i++)
462 		outb(mux_8012[i], ioaddr + PAR_DATA);
463 	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
464 
465     for (i = 0; i < 6; i++)
466 		write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
467 
468 	write_reg_high(ioaddr, CMR2, lp->addr_mode);
469 
470 	if (net_debug > 2) {
471 		printk(KERN_DEBUG "%s: Reset: current Rx mode %d.\n", dev->name,
472 			   (read_nibble(ioaddr, CMR2_h) >> 3) & 0x0f);
473 	}
474 
475     write_reg(ioaddr, CMR2, CMR2_IRQOUT);
476     write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);
477 
478 	/* Enable the interrupt line from the serial port. */
479 	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
480 
481 	/* Unmask the interesting interrupts. */
482     write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
483     write_reg_high(ioaddr, IMR, ISRh_RxErr);
484 
485 	lp->tx_unit_busy = 0;
486     lp->pac_cnt_in_tx_buf = 0;
487 	lp->saved_tx_size = 0;
488 }
489 
490 static void trigger_send(long ioaddr, int length)
491 {
492 	write_reg_byte(ioaddr, TxCNT0, length & 0xff);
493 	write_reg(ioaddr, TxCNT1, length >> 8);
494 	write_reg(ioaddr, CMR1, CMR1_Xmit);
495 }
496 
497 static void write_packet(long ioaddr, int length, unsigned char *packet, int pad_len, int data_mode)
498 {
499     if (length & 1)
500     {
501     	length++;
502     	pad_len++;
503     }
504 
505     outb(EOC+MAR, ioaddr + PAR_DATA);
506     if ((data_mode & 1) == 0) {
507 		/* Write the packet out, starting with the write addr. */
508 		outb(WrAddr+MAR, ioaddr + PAR_DATA);
509 		do {
510 			write_byte_mode0(ioaddr, *packet++);
511 		} while (--length > pad_len) ;
512 		do {
513 			write_byte_mode0(ioaddr, 0);
514 		} while (--length > 0) ;
515     } else {
516 		/* Write the packet out in slow mode. */
517 		unsigned char outbyte = *packet++;
518 
519 		outb(Ctrl_LNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
520 		outb(WrAddr+MAR, ioaddr + PAR_DATA);
521 
522 		outb((outbyte & 0x0f)|0x40, ioaddr + PAR_DATA);
523 		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
524 		outbyte >>= 4;
525 		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
526 		outb(Ctrl_HNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
527 		while (--length > pad_len)
528 			write_byte_mode1(ioaddr, *packet++);
529 		while (--length > 0)
530 			write_byte_mode1(ioaddr, 0);
531     }
532     /* Terminate the Tx frame.  End of write: ECB. */
533     outb(0xff, ioaddr + PAR_DATA);
534     outb(Ctrl_HNibWrite | Ctrl_SelData | Ctrl_IRQEN, ioaddr + PAR_CONTROL);
535 }
536 
537 static void tx_timeout(struct net_device *dev)
538 {
539 	long ioaddr = dev->base_addr;
540 
541 	printk(KERN_WARNING "%s: Transmit timed out, %s?\n", dev->name,
542 		   inb(ioaddr + PAR_CONTROL) & 0x10 ? "network cable problem"
543 		   :  "IRQ conflict");
544 	dev->stats.tx_errors++;
545 	/* Try to restart the adapter. */
546 	hardware_init(dev);
547 	dev->trans_start = jiffies; /* prevent tx timeout */
548 	netif_wake_queue(dev);
549 	dev->stats.tx_errors++;
550 }
551 
552 static netdev_tx_t atp_send_packet(struct sk_buff *skb,
553 				   struct net_device *dev)
554 {
555 	struct net_local *lp = netdev_priv(dev);
556 	long ioaddr = dev->base_addr;
557 	int length;
558 	unsigned long flags;
559 
560 	length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
561 
562 	netif_stop_queue(dev);
563 
564 	/* Disable interrupts by writing 0x00 to the Interrupt Mask Register.
565 	   This sequence must not be interrupted by an incoming packet. */
566 
567 	spin_lock_irqsave(&lp->lock, flags);
568 	write_reg(ioaddr, IMR, 0);
569 	write_reg_high(ioaddr, IMR, 0);
570 	spin_unlock_irqrestore(&lp->lock, flags);
571 
572 	write_packet(ioaddr, length, skb->data, length-skb->len, dev->if_port);
573 
574 	lp->pac_cnt_in_tx_buf++;
575 	if (lp->tx_unit_busy == 0) {
576 		trigger_send(ioaddr, length);
577 		lp->saved_tx_size = 0; 				/* Redundant */
578 		lp->re_tx = 0;
579 		lp->tx_unit_busy = 1;
580 	} else
581 		lp->saved_tx_size = length;
582 	/* Re-enable the LPT interrupts. */
583 	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
584 	write_reg_high(ioaddr, IMR, ISRh_RxErr);
585 
586 	dev_kfree_skb (skb);
587 	return NETDEV_TX_OK;
588 }
589 
590 
591 /* The typical workload of the driver:
592    Handle the network interface interrupts. */
593 static irqreturn_t atp_interrupt(int irq, void *dev_instance)
594 {
595 	struct net_device *dev = dev_instance;
596 	struct net_local *lp;
597 	long ioaddr;
598 	static int num_tx_since_rx;
599 	int boguscount = max_interrupt_work;
600 	int handled = 0;
601 
602 	ioaddr = dev->base_addr;
603 	lp = netdev_priv(dev);
604 
605 	spin_lock(&lp->lock);
606 
607 	/* Disable additional spurious interrupts. */
608 	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);
609 
610 	/* The adapter's output is currently the IRQ line, switch it to data. */
611 	write_reg(ioaddr, CMR2, CMR2_NULL);
612 	write_reg(ioaddr, IMR, 0);
613 
614 	if (net_debug > 5) printk(KERN_DEBUG "%s: In interrupt ", dev->name);
615     while (--boguscount > 0) {
616 		int status = read_nibble(ioaddr, ISR);
617 		if (net_debug > 5) printk("loop status %02x..", status);
618 
619 		if (status & (ISR_RxOK<<3)) {
620 			handled = 1;
621 			write_reg(ioaddr, ISR, ISR_RxOK); /* Clear the Rx interrupt. */
622 			do {
623 				int read_status = read_nibble(ioaddr, CMR1);
624 				if (net_debug > 6)
625 					printk("handling Rx packet %02x..", read_status);
626 				/* We acknowledged the normal Rx interrupt, so if the interrupt
627 				   is still outstanding we must have a Rx error. */
628 				if (read_status & (CMR1_IRQ << 3)) { /* Overrun. */
629 					dev->stats.rx_over_errors++;
630 					/* Set to no-accept mode long enough to remove a packet. */
631 					write_reg_high(ioaddr, CMR2, CMR2h_OFF);
632 					net_rx(dev);
633 					/* Clear the interrupt and return to normal Rx mode. */
634 					write_reg_high(ioaddr, ISR, ISRh_RxErr);
635 					write_reg_high(ioaddr, CMR2, lp->addr_mode);
636 				} else if ((read_status & (CMR1_BufEnb << 3)) == 0) {
637 					net_rx(dev);
638 					num_tx_since_rx = 0;
639 				} else
640 					break;
641 			} while (--boguscount > 0);
642 		} else if (status & ((ISR_TxErr + ISR_TxOK)<<3)) {
643 			handled = 1;
644 			if (net_debug > 6)  printk("handling Tx done..");
645 			/* Clear the Tx interrupt.  We should check for too many failures
646 			   and reinitialize the adapter. */
647 			write_reg(ioaddr, ISR, ISR_TxErr + ISR_TxOK);
648 			if (status & (ISR_TxErr<<3)) {
649 				dev->stats.collisions++;
650 				if (++lp->re_tx > 15) {
651 					dev->stats.tx_aborted_errors++;
652 					hardware_init(dev);
653 					break;
654 				}
655 				/* Attempt to retransmit. */
656 				if (net_debug > 6)  printk("attempting to ReTx");
657 				write_reg(ioaddr, CMR1, CMR1_ReXmit + CMR1_Xmit);
658 			} else {
659 				/* Finish up the transmit. */
660 				dev->stats.tx_packets++;
661 				lp->pac_cnt_in_tx_buf--;
662 				if ( lp->saved_tx_size) {
663 					trigger_send(ioaddr, lp->saved_tx_size);
664 					lp->saved_tx_size = 0;
665 					lp->re_tx = 0;
666 				} else
667 					lp->tx_unit_busy = 0;
668 				netif_wake_queue(dev);	/* Inform upper layers. */
669 			}
670 			num_tx_since_rx++;
671 		} else if (num_tx_since_rx > 8 &&
672 			   time_after(jiffies, dev->last_rx + HZ)) {
673 			if (net_debug > 2)
674 				printk(KERN_DEBUG "%s: Missed packet? No Rx after %d Tx and "
675 					   "%ld jiffies status %02x  CMR1 %02x.\n", dev->name,
676 					   num_tx_since_rx, jiffies - dev->last_rx, status,
677 					   (read_nibble(ioaddr, CMR1) >> 3) & 15);
678 			dev->stats.rx_missed_errors++;
679 			hardware_init(dev);
680 			num_tx_since_rx = 0;
681 			break;
682 		} else
683 			break;
684     }
685 
686 	/* This following code fixes a rare (and very difficult to track down)
687 	   problem where the adapter forgets its ethernet address. */
688 	{
689 		int i;
690 		for (i = 0; i < 6; i++)
691 			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
692 #if 0 && defined(TIMED_CHECKER)
693 		mod_timer(&lp->timer, jiffies + TIMED_CHECKER);
694 #endif
695 	}
696 
697 	/* Tell the adapter that it can go back to using the output line as IRQ. */
698     write_reg(ioaddr, CMR2, CMR2_IRQOUT);
699 	/* Enable the physical interrupt line, which is sure to be low until.. */
700 	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
701 	/* .. we enable the interrupt sources. */
702 	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
703 	write_reg_high(ioaddr, IMR, ISRh_RxErr); 			/* Hmmm, really needed? */
704 
705 	spin_unlock(&lp->lock);
706 
707 	if (net_debug > 5) printk("exiting interrupt.\n");
708 	return IRQ_RETVAL(handled);
709 }
710 
711 #ifdef TIMED_CHECKER
712 /* This following code fixes a rare (and very difficult to track down)
713    problem where the adapter forgets its ethernet address. */
714 static void atp_timed_checker(unsigned long data)
715 {
716 	struct net_device *dev = (struct net_device *)data;
717 	long ioaddr = dev->base_addr;
718 	struct net_local *lp = netdev_priv(dev);
719 	int tickssofar = jiffies - lp->last_rx_time;
720 	int i;
721 
722 	spin_lock(&lp->lock);
723 	if (tickssofar > 2*HZ) {
724 #if 1
725 		for (i = 0; i < 6; i++)
726 			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
727 		lp->last_rx_time = jiffies;
728 #else
729 		for (i = 0; i < 6; i++)
730 			if (read_cmd_byte(ioaddr, PAR0 + i) != atp_timed_dev->dev_addr[i])
731 				{
732 			struct net_local *lp = netdev_priv(atp_timed_dev);
733 			write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
734 			if (i == 2)
735 			  dev->stats.tx_errors++;
736 			else if (i == 3)
737 			  dev->stats.tx_dropped++;
738 			else if (i == 4)
739 			  dev->stats.collisions++;
740 			else
741 			  dev->stats.rx_errors++;
742 		  }
743 #endif
744 	}
745 	spin_unlock(&lp->lock);
746 	lp->timer.expires = jiffies + TIMED_CHECKER;
747 	add_timer(&lp->timer);
748 }
749 #endif
750 
751 /* We have a good packet(s), get it/them out of the buffers. */
752 static void net_rx(struct net_device *dev)
753 {
754 	struct net_local *lp = netdev_priv(dev);
755 	long ioaddr = dev->base_addr;
756 	struct rx_header rx_head;
757 
758 	/* Process the received packet. */
759 	outb(EOC+MAR, ioaddr + PAR_DATA);
760 	read_block(ioaddr, 8, (unsigned char*)&rx_head, dev->if_port);
761 	if (net_debug > 5)
762 		printk(KERN_DEBUG " rx_count %04x %04x %04x %04x..", rx_head.pad,
763 			   rx_head.rx_count, rx_head.rx_status, rx_head.cur_addr);
764 	if ((rx_head.rx_status & 0x77) != 0x01) {
765 		dev->stats.rx_errors++;
766 		if (rx_head.rx_status & 0x0004) dev->stats.rx_frame_errors++;
767 		else if (rx_head.rx_status & 0x0002) dev->stats.rx_crc_errors++;
768 		if (net_debug > 3)
769 			printk(KERN_DEBUG "%s: Unknown ATP Rx error %04x.\n",
770 				   dev->name, rx_head.rx_status);
771 		if  (rx_head.rx_status & 0x0020) {
772 			dev->stats.rx_fifo_errors++;
773 			write_reg_high(ioaddr, CMR1, CMR1h_TxENABLE);
774 			write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);
775 		} else if (rx_head.rx_status & 0x0050)
776 			hardware_init(dev);
777 		return;
778 	} else {
779 		/* Malloc up new buffer. The "-4" omits the FCS (CRC). */
780 		int pkt_len = (rx_head.rx_count & 0x7ff) - 4;
781 		struct sk_buff *skb;
782 
783 		skb = netdev_alloc_skb(dev, pkt_len + 2);
784 		if (skb == NULL) {
785 			dev->stats.rx_dropped++;
786 			goto done;
787 		}
788 
789 		skb_reserve(skb, 2);	/* Align IP on 16 byte boundaries */
790 		read_block(ioaddr, pkt_len, skb_put(skb,pkt_len), dev->if_port);
791 		skb->protocol = eth_type_trans(skb, dev);
792 		netif_rx(skb);
793 		dev->last_rx = jiffies;
794 		dev->stats.rx_packets++;
795 		dev->stats.rx_bytes += pkt_len;
796 	}
797  done:
798 	write_reg(ioaddr, CMR1, CMR1_NextPkt);
799 	lp->last_rx_time = jiffies;
800 }
801 
802 static void read_block(long ioaddr, int length, unsigned char *p, int data_mode)
803 {
804 	if (data_mode <= 3) { /* Mode 0 or 1 */
805 		outb(Ctrl_LNibRead, ioaddr + PAR_CONTROL);
806 		outb(length == 8  ?  RdAddr | HNib | MAR  :  RdAddr | MAR,
807 			 ioaddr + PAR_DATA);
808 		if (data_mode <= 1) { /* Mode 0 or 1 */
809 			do { *p++ = read_byte_mode0(ioaddr); } while (--length > 0);
810 		} else { /* Mode 2 or 3 */
811 			do { *p++ = read_byte_mode2(ioaddr); } while (--length > 0);
812 		}
813 	} else if (data_mode <= 5) {
814 		do { *p++ = read_byte_mode4(ioaddr); } while (--length > 0);
815 	} else {
816 		do { *p++ = read_byte_mode6(ioaddr); } while (--length > 0);
817 	}
818 
819 	outb(EOC+HNib+MAR, ioaddr + PAR_DATA);
820 	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);
821 }
822 
823 /* The inverse routine to net_open(). */
824 static int
825 net_close(struct net_device *dev)
826 {
827 	struct net_local *lp = netdev_priv(dev);
828 	long ioaddr = dev->base_addr;
829 
830 	netif_stop_queue(dev);
831 
832 	del_timer_sync(&lp->timer);
833 
834 	/* Flush the Tx and disable Rx here. */
835 	lp->addr_mode = CMR2h_OFF;
836 	write_reg_high(ioaddr, CMR2, CMR2h_OFF);
837 
838 	/* Free the IRQ line. */
839 	outb(0x00, ioaddr + PAR_CONTROL);
840 	free_irq(dev->irq, dev);
841 
842 	/* Reset the ethernet hardware and activate the printer pass-through. */
843 	write_reg_high(ioaddr, CMR1, CMR1h_RESET | CMR1h_MUX);
844 	return 0;
845 }
846 
847 /*
848  *	Set or clear the multicast filter for this adapter.
849  */
850 
851 static void set_rx_mode(struct net_device *dev)
852 {
853 	struct net_local *lp = netdev_priv(dev);
854 	long ioaddr = dev->base_addr;
855 
856 	if (!netdev_mc_empty(dev) || (dev->flags & (IFF_ALLMULTI|IFF_PROMISC)))
857 		lp->addr_mode = CMR2h_PROMISC;
858 	else
859 		lp->addr_mode = CMR2h_Normal;
860 	write_reg_high(ioaddr, CMR2, lp->addr_mode);
861 }
862 
863 static int __init atp_init_module(void) {
864 	if (debug)					/* Emit version even if no cards detected. */
865 		printk(KERN_INFO "%s", version);
866 	return atp_init();
867 }
868 
869 static void __exit atp_cleanup_module(void) {
870 	struct net_device *next_dev;
871 
872 	while (root_atp_dev) {
873 		struct net_local *atp_local = netdev_priv(root_atp_dev);
874 		next_dev = atp_local->next_module;
875 		unregister_netdev(root_atp_dev);
876 		/* No need to release_region(), since we never snarf it. */
877 		free_netdev(root_atp_dev);
878 		root_atp_dev = next_dev;
879 	}
880 }
881 
882 module_init(atp_init_module);
883 module_exit(atp_cleanup_module);
884