xref: /openbmc/linux/drivers/net/wan/n2.c (revision 9dbbc3b9)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * SDL Inc. RISCom/N2 synchronous serial card driver for Linux
4  *
5  * Copyright (C) 1998-2003 Krzysztof Halasa <khc@pm.waw.pl>
6  *
7  * For information see <https://www.kernel.org/pub/linux/utils/net/hdlc/>
8  *
9  * Note: integrated CSU/DSU/DDS are not supported by this driver
10  *
11  * Sources of information:
12  *    Hitachi HD64570 SCA User's Manual
13  *    SDL Inc. PPP/HDLC/CISCO driver
14  */
15 
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 
18 #include <linux/module.h>
19 #include <linux/kernel.h>
20 #include <linux/capability.h>
21 #include <linux/slab.h>
22 #include <linux/types.h>
23 #include <linux/fcntl.h>
24 #include <linux/in.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <linux/init.h>
28 #include <linux/ioport.h>
29 #include <linux/moduleparam.h>
30 #include <linux/netdevice.h>
31 #include <linux/hdlc.h>
32 #include <asm/io.h>
33 #include "hd64570.h"
34 
35 static const char *version = "SDL RISCom/N2 driver version: 1.15";
36 static const char *devname = "RISCom/N2";
37 
38 #undef DEBUG_PKT
39 #define DEBUG_RINGS
40 
41 #define USE_WINDOWSIZE 16384
42 #define USE_BUS16BITS 1
43 #define CLOCK_BASE 9830400	/* 9.8304 MHz */
44 #define MAX_PAGES      16	/* 16 RAM pages at max */
45 #define MAX_RAM_SIZE 0x80000	/* 512 KB */
46 #if MAX_RAM_SIZE > MAX_PAGES * USE_WINDOWSIZE
47 #undef MAX_RAM_SIZE
48 #define MAX_RAM_SIZE (MAX_PAGES * USE_WINDOWSIZE)
49 #endif
50 #define N2_IOPORTS 0x10
51 #define NEED_DETECT_RAM
52 #define NEED_SCA_MSCI_INTR
53 #define MAX_TX_BUFFERS 10
54 
55 static char *hw;	/* pointer to hw=xxx command line string */
56 
57 /* RISCom/N2 Board Registers */
58 
59 /* PC Control Register */
60 #define N2_PCR 0
61 #define PCR_RUNSCA 1     /* Run 64570 */
62 #define PCR_VPM    2     /* Enable VPM - needed if using RAM above 1 MB */
63 #define PCR_ENWIN  4     /* Open window */
64 #define PCR_BUS16  8     /* 16-bit bus */
65 
66 /* Memory Base Address Register */
67 #define N2_BAR 2
68 
69 /* Page Scan Register  */
70 #define N2_PSR 4
71 #define WIN16K       0x00
72 #define WIN32K       0x20
73 #define WIN64K       0x40
74 #define PSR_WINBITS  0x60
75 #define PSR_DMAEN    0x80
76 #define PSR_PAGEBITS 0x0F
77 
78 /* Modem Control Reg */
79 #define N2_MCR 6
80 #define CLOCK_OUT_PORT1 0x80
81 #define CLOCK_OUT_PORT0 0x40
82 #define TX422_PORT1     0x20
83 #define TX422_PORT0     0x10
84 #define DSR_PORT1       0x08
85 #define DSR_PORT0       0x04
86 #define DTR_PORT1       0x02
87 #define DTR_PORT0       0x01
88 
89 typedef struct port_s {
90 	struct net_device *dev;
91 	struct card_s *card;
92 	spinlock_t lock;	/* TX lock */
93 	sync_serial_settings settings;
94 	int valid;		/* port enabled */
95 	int rxpart;		/* partial frame received, next frame invalid*/
96 	unsigned short encoding;
97 	unsigned short parity;
98 	u16 rxin;		/* rx ring buffer 'in' pointer */
99 	u16 txin;		/* tx ring buffer 'in' and 'last' pointers */
100 	u16 txlast;
101 	u8 rxs, txs, tmc;	/* SCA registers */
102 	u8 phy_node;		/* physical port # - 0 or 1 */
103 	u8 log_node;		/* logical port # */
104 } port_t;
105 
106 typedef struct card_s {
107 	u8 __iomem *winbase;		/* ISA window base address */
108 	u32 phy_winbase;	/* ISA physical base address */
109 	u32 ram_size;		/* number of bytes */
110 	u16 io;			/* IO Base address */
111 	u16 buff_offset;	/* offset of first buffer of first channel */
112 	u16 rx_ring_buffers;	/* number of buffers in a ring */
113 	u16 tx_ring_buffers;
114 	u8 irq;			/* IRQ (3-15) */
115 
116 	port_t ports[2];
117 	struct card_s *next_card;
118 } card_t;
119 
120 static card_t *first_card;
121 static card_t **new_card = &first_card;
122 
123 #define sca_reg(reg, card) (0x8000 | (card)->io | \
124 			    ((reg) & 0x0F) | (((reg) & 0xF0) << 6))
125 #define sca_in(reg, card)		inb(sca_reg(reg, card))
126 #define sca_out(value, reg, card)	outb(value, sca_reg(reg, card))
127 #define sca_inw(reg, card)		inw(sca_reg(reg, card))
128 #define sca_outw(value, reg, card)	outw(value, sca_reg(reg, card))
129 
130 #define port_to_card(port)		((port)->card)
131 #define log_node(port)			((port)->log_node)
132 #define phy_node(port)			((port)->phy_node)
133 #define winsize(card)			(USE_WINDOWSIZE)
134 #define winbase(card)      	     	((card)->winbase)
135 #define get_port(card, port)		((card)->ports[port].valid ? \
136 					 &(card)->ports[port] : NULL)
137 
138 static __inline__ u8 sca_get_page(card_t *card)
139 {
140 	return inb(card->io + N2_PSR) & PSR_PAGEBITS;
141 }
142 
143 static __inline__ void openwin(card_t *card, u8 page)
144 {
145 	u8 psr = inb(card->io + N2_PSR);
146 
147 	outb((psr & ~PSR_PAGEBITS) | page, card->io + N2_PSR);
148 }
149 
150 #include "hd64570.c"
151 
152 static void n2_set_iface(port_t *port)
153 {
154 	card_t *card = port->card;
155 	int io = card->io;
156 	u8 mcr = inb(io + N2_MCR);
157 	u8 msci = get_msci(port);
158 	u8 rxs = port->rxs & CLK_BRG_MASK;
159 	u8 txs = port->txs & CLK_BRG_MASK;
160 
161 	switch (port->settings.clock_type) {
162 	case CLOCK_INT:
163 		mcr |= port->phy_node ? CLOCK_OUT_PORT1 : CLOCK_OUT_PORT0;
164 		rxs |= CLK_BRG_RX; /* BRG output */
165 		txs |= CLK_RXCLK_TX; /* RX clock */
166 		break;
167 
168 	case CLOCK_TXINT:
169 		mcr |= port->phy_node ? CLOCK_OUT_PORT1 : CLOCK_OUT_PORT0;
170 		rxs |= CLK_LINE_RX; /* RXC input */
171 		txs |= CLK_BRG_TX; /* BRG output */
172 		break;
173 
174 	case CLOCK_TXFROMRX:
175 		mcr |= port->phy_node ? CLOCK_OUT_PORT1 : CLOCK_OUT_PORT0;
176 		rxs |= CLK_LINE_RX; /* RXC input */
177 		txs |= CLK_RXCLK_TX; /* RX clock */
178 		break;
179 
180 	default:		/* Clock EXTernal */
181 		mcr &= port->phy_node ? ~CLOCK_OUT_PORT1 : ~CLOCK_OUT_PORT0;
182 		rxs |= CLK_LINE_RX; /* RXC input */
183 		txs |= CLK_LINE_TX; /* TXC input */
184 	}
185 
186 	outb(mcr, io + N2_MCR);
187 	port->rxs = rxs;
188 	port->txs = txs;
189 	sca_out(rxs, msci + RXS, card);
190 	sca_out(txs, msci + TXS, card);
191 	sca_set_port(port);
192 }
193 
194 static int n2_open(struct net_device *dev)
195 {
196 	port_t *port = dev_to_port(dev);
197 	int io = port->card->io;
198 	u8 mcr = inb(io + N2_MCR) |
199 		(port->phy_node ? TX422_PORT1 : TX422_PORT0);
200 	int result;
201 
202 	result = hdlc_open(dev);
203 	if (result)
204 		return result;
205 
206 	mcr &= port->phy_node ? ~DTR_PORT1 : ~DTR_PORT0; /* set DTR ON */
207 	outb(mcr, io + N2_MCR);
208 
209 	outb(inb(io + N2_PCR) | PCR_ENWIN, io + N2_PCR); /* open window */
210 	outb(inb(io + N2_PSR) | PSR_DMAEN, io + N2_PSR); /* enable dma */
211 	sca_open(dev);
212 	n2_set_iface(port);
213 	return 0;
214 }
215 
216 static int n2_close(struct net_device *dev)
217 {
218 	port_t *port = dev_to_port(dev);
219 	int io = port->card->io;
220 	u8 mcr = inb(io + N2_MCR) |
221 		(port->phy_node ? TX422_PORT1 : TX422_PORT0);
222 
223 	sca_close(dev);
224 	mcr |= port->phy_node ? DTR_PORT1 : DTR_PORT0; /* set DTR OFF */
225 	outb(mcr, io + N2_MCR);
226 	hdlc_close(dev);
227 	return 0;
228 }
229 
230 static int n2_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
231 {
232 	const size_t size = sizeof(sync_serial_settings);
233 	sync_serial_settings new_line;
234 	sync_serial_settings __user *line = ifr->ifr_settings.ifs_ifsu.sync;
235 	port_t *port = dev_to_port(dev);
236 
237 #ifdef DEBUG_RINGS
238 	if (cmd == SIOCDEVPRIVATE) {
239 		sca_dump_rings(dev);
240 		return 0;
241 	}
242 #endif
243 	if (cmd != SIOCWANDEV)
244 		return hdlc_ioctl(dev, ifr, cmd);
245 
246 	switch (ifr->ifr_settings.type) {
247 	case IF_GET_IFACE:
248 		ifr->ifr_settings.type = IF_IFACE_SYNC_SERIAL;
249 		if (ifr->ifr_settings.size < size) {
250 			ifr->ifr_settings.size = size; /* data size wanted */
251 			return -ENOBUFS;
252 		}
253 		if (copy_to_user(line, &port->settings, size))
254 			return -EFAULT;
255 		return 0;
256 
257 	case IF_IFACE_SYNC_SERIAL:
258 		if (!capable(CAP_NET_ADMIN))
259 			return -EPERM;
260 
261 		if (copy_from_user(&new_line, line, size))
262 			return -EFAULT;
263 
264 		if (new_line.clock_type != CLOCK_EXT &&
265 		    new_line.clock_type != CLOCK_TXFROMRX &&
266 		    new_line.clock_type != CLOCK_INT &&
267 		    new_line.clock_type != CLOCK_TXINT)
268 			return -EINVAL;	/* No such clock setting */
269 
270 		if (new_line.loopback != 0 && new_line.loopback != 1)
271 			return -EINVAL;
272 
273 		memcpy(&port->settings, &new_line, size); /* Update settings */
274 		n2_set_iface(port);
275 		return 0;
276 
277 	default:
278 		return hdlc_ioctl(dev, ifr, cmd);
279 	}
280 }
281 
282 static void n2_destroy_card(card_t *card)
283 {
284 	int cnt;
285 
286 	for (cnt = 0; cnt < 2; cnt++)
287 		if (card->ports[cnt].card) {
288 			struct net_device *dev = port_to_dev(&card->ports[cnt]);
289 
290 			unregister_hdlc_device(dev);
291 		}
292 
293 	if (card->irq)
294 		free_irq(card->irq, card);
295 
296 	if (card->winbase) {
297 		iounmap(card->winbase);
298 		release_mem_region(card->phy_winbase, USE_WINDOWSIZE);
299 	}
300 
301 	if (card->io)
302 		release_region(card->io, N2_IOPORTS);
303 	if (card->ports[0].dev)
304 		free_netdev(card->ports[0].dev);
305 	if (card->ports[1].dev)
306 		free_netdev(card->ports[1].dev);
307 	kfree(card);
308 }
309 
310 static const struct net_device_ops n2_ops = {
311 	.ndo_open       = n2_open,
312 	.ndo_stop       = n2_close,
313 	.ndo_start_xmit = hdlc_start_xmit,
314 	.ndo_do_ioctl   = n2_ioctl,
315 };
316 
317 static int __init n2_run(unsigned long io, unsigned long irq,
318 			 unsigned long winbase, long valid0, long valid1)
319 {
320 	card_t *card;
321 	u8 cnt, pcr;
322 	int i;
323 
324 	if (io < 0x200 || io > 0x3FF || (io % N2_IOPORTS) != 0) {
325 		pr_err("invalid I/O port value\n");
326 		return -ENODEV;
327 	}
328 
329 	if (irq < 3 || irq > 15 || irq == 6) /* FIXME */ {
330 		pr_err("invalid IRQ value\n");
331 		return -ENODEV;
332 	}
333 
334 	if (winbase < 0xA0000 || winbase > 0xFFFFF || (winbase & 0xFFF) != 0) {
335 		pr_err("invalid RAM value\n");
336 		return -ENODEV;
337 	}
338 
339 	card = kzalloc(sizeof(card_t), GFP_KERNEL);
340 	if (!card)
341 		return -ENOBUFS;
342 
343 	card->ports[0].dev = alloc_hdlcdev(&card->ports[0]);
344 	card->ports[1].dev = alloc_hdlcdev(&card->ports[1]);
345 	if (!card->ports[0].dev || !card->ports[1].dev) {
346 		pr_err("unable to allocate memory\n");
347 		n2_destroy_card(card);
348 		return -ENOMEM;
349 	}
350 
351 	if (!request_region(io, N2_IOPORTS, devname)) {
352 		pr_err("I/O port region in use\n");
353 		n2_destroy_card(card);
354 		return -EBUSY;
355 	}
356 	card->io = io;
357 
358 	if (request_irq(irq, sca_intr, 0, devname, card)) {
359 		pr_err("could not allocate IRQ\n");
360 		n2_destroy_card(card);
361 		return -EBUSY;
362 	}
363 	card->irq = irq;
364 
365 	if (!request_mem_region(winbase, USE_WINDOWSIZE, devname)) {
366 		pr_err("could not request RAM window\n");
367 		n2_destroy_card(card);
368 		return -EBUSY;
369 	}
370 	card->phy_winbase = winbase;
371 	card->winbase = ioremap(winbase, USE_WINDOWSIZE);
372 	if (!card->winbase) {
373 		pr_err("ioremap() failed\n");
374 		n2_destroy_card(card);
375 		return -EFAULT;
376 	}
377 
378 	outb(0, io + N2_PCR);
379 	outb(winbase >> 12, io + N2_BAR);
380 
381 	switch (USE_WINDOWSIZE) {
382 	case 16384:
383 		outb(WIN16K, io + N2_PSR);
384 		break;
385 
386 	case 32768:
387 		outb(WIN32K, io + N2_PSR);
388 		break;
389 
390 	case 65536:
391 		outb(WIN64K, io + N2_PSR);
392 		break;
393 
394 	default:
395 		pr_err("invalid window size\n");
396 		n2_destroy_card(card);
397 		return -ENODEV;
398 	}
399 
400 	pcr = PCR_ENWIN | PCR_VPM | (USE_BUS16BITS ? PCR_BUS16 : 0);
401 	outb(pcr, io + N2_PCR);
402 
403 	card->ram_size = sca_detect_ram(card, card->winbase, MAX_RAM_SIZE);
404 
405 	/* number of TX + RX buffers for one port */
406 	i = card->ram_size / ((valid0 + valid1) * (sizeof(pkt_desc) +
407 						   HDLC_MAX_MRU));
408 
409 	card->tx_ring_buffers = min(i / 2, MAX_TX_BUFFERS);
410 	card->rx_ring_buffers = i - card->tx_ring_buffers;
411 
412 	card->buff_offset = (valid0 + valid1) * sizeof(pkt_desc) *
413 		(card->tx_ring_buffers + card->rx_ring_buffers);
414 
415 	pr_info("RISCom/N2 %u KB RAM, IRQ%u, using %u TX + %u RX packets rings\n",
416 		card->ram_size / 1024, card->irq,
417 		card->tx_ring_buffers, card->rx_ring_buffers);
418 
419 	if (card->tx_ring_buffers < 1) {
420 		pr_err("RAM test failed\n");
421 		n2_destroy_card(card);
422 		return -EIO;
423 	}
424 
425 	pcr |= PCR_RUNSCA;		/* run SCA */
426 	outb(pcr, io + N2_PCR);
427 	outb(0, io + N2_MCR);
428 
429 	sca_init(card, 0);
430 	for (cnt = 0; cnt < 2; cnt++) {
431 		port_t *port = &card->ports[cnt];
432 		struct net_device *dev = port_to_dev(port);
433 		hdlc_device *hdlc = dev_to_hdlc(dev);
434 
435 		if ((cnt == 0 && !valid0) || (cnt == 1 && !valid1))
436 			continue;
437 
438 		port->phy_node = cnt;
439 		port->valid = 1;
440 
441 		if ((cnt == 1) && valid0)
442 			port->log_node = 1;
443 
444 		spin_lock_init(&port->lock);
445 		dev->irq = irq;
446 		dev->mem_start = winbase;
447 		dev->mem_end = winbase + USE_WINDOWSIZE - 1;
448 		dev->tx_queue_len = 50;
449 		dev->netdev_ops = &n2_ops;
450 		hdlc->attach = sca_attach;
451 		hdlc->xmit = sca_xmit;
452 		port->settings.clock_type = CLOCK_EXT;
453 		port->card = card;
454 
455 		if (register_hdlc_device(dev)) {
456 			pr_warn("unable to register hdlc device\n");
457 			port->card = NULL;
458 			n2_destroy_card(card);
459 			return -ENOBUFS;
460 		}
461 		sca_init_port(port); /* Set up SCA memory */
462 
463 		netdev_info(dev, "RISCom/N2 node %d\n", port->phy_node);
464 	}
465 
466 	*new_card = card;
467 	new_card = &card->next_card;
468 
469 	return 0;
470 }
471 
472 static int __init n2_init(void)
473 {
474 	if (!hw) {
475 #ifdef MODULE
476 		pr_info("no card initialized\n");
477 #endif
478 		return -EINVAL;	/* no parameters specified, abort */
479 	}
480 
481 	pr_info("%s\n", version);
482 
483 	do {
484 		unsigned long io, irq, ram;
485 		long valid[2] = { 0, 0 }; /* Default = both ports disabled */
486 
487 		io = simple_strtoul(hw, &hw, 0);
488 
489 		if (*hw++ != ',')
490 			break;
491 		irq = simple_strtoul(hw, &hw, 0);
492 
493 		if (*hw++ != ',')
494 			break;
495 		ram = simple_strtoul(hw, &hw, 0);
496 
497 		if (*hw++ != ',')
498 			break;
499 		while (1) {
500 			if (*hw == '0' && !valid[0])
501 				valid[0] = 1; /* Port 0 enabled */
502 			else if (*hw == '1' && !valid[1])
503 				valid[1] = 1; /* Port 1 enabled */
504 			else
505 				break;
506 			hw++;
507 		}
508 
509 		if (!valid[0] && !valid[1])
510 			break;	/* at least one port must be used */
511 
512 		if (*hw == ':' || *hw == '\x0')
513 			n2_run(io, irq, ram, valid[0], valid[1]);
514 
515 		if (*hw == '\x0')
516 			return first_card ? 0 : -EINVAL;
517 	} while (*hw++ == ':');
518 
519 	pr_err("invalid hardware parameters\n");
520 	return first_card ? 0 : -EINVAL;
521 }
522 
523 static void __exit n2_cleanup(void)
524 {
525 	card_t *card = first_card;
526 
527 	while (card) {
528 		card_t *ptr = card;
529 
530 		card = card->next_card;
531 		n2_destroy_card(ptr);
532 	}
533 }
534 
535 module_init(n2_init);
536 module_exit(n2_cleanup);
537 
538 MODULE_AUTHOR("Krzysztof Halasa <khc@pm.waw.pl>");
539 MODULE_DESCRIPTION("RISCom/N2 serial port driver");
540 MODULE_LICENSE("GPL v2");
541 module_param(hw, charp, 0444);
542 MODULE_PARM_DESC(hw, "io,irq,ram,ports:io,irq,...");
543