xref: /openbmc/linux/drivers/parport/parport_gsc.c (revision 2e1b1d70)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *      Low-level parallel-support for PC-style hardware integrated in the
4  *	LASI-Controller (on GSC-Bus) for HP-PARISC Workstations
5  *
6  *	(C) 1999-2001 by Helge Deller <deller@gmx.de>
7  *
8  * based on parport_pc.c by
9  * 	    Grant Guenther <grant@torque.net>
10  * 	    Phil Blundell <philb@gnu.org>
11  *          Tim Waugh <tim@cyberelk.demon.co.uk>
12  *	    Jose Renau <renau@acm.org>
13  *          David Campbell
14  *          Andrea Arcangeli
15  */
16 
17 #undef DEBUG	/* undef for production */
18 
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/delay.h>
22 #include <linux/errno.h>
23 #include <linux/interrupt.h>
24 #include <linux/ioport.h>
25 #include <linux/kernel.h>
26 #include <linux/slab.h>
27 #include <linux/pci.h>
28 #include <linux/sysctl.h>
29 
30 #include <asm/io.h>
31 #include <linux/uaccess.h>
32 #include <asm/superio.h>
33 
34 #include <linux/parport.h>
35 #include <asm/pdc.h>
36 #include <asm/parisc-device.h>
37 #include <asm/hardware.h>
38 #include "parport_gsc.h"
39 
40 
41 MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
42 MODULE_DESCRIPTION("HP-PARISC PC-style parallel port driver");
43 MODULE_LICENSE("GPL");
44 
45 
46 /*
47  * Clear TIMEOUT BIT in EPP MODE
48  *
49  * This is also used in SPP detection.
50  */
clear_epp_timeout(struct parport * pb)51 static int clear_epp_timeout(struct parport *pb)
52 {
53 	unsigned char r;
54 
55 	if (!(parport_gsc_read_status(pb) & 0x01))
56 		return 1;
57 
58 	/* To clear timeout some chips require double read */
59 	parport_gsc_read_status(pb);
60 	r = parport_gsc_read_status(pb);
61 	parport_writeb (r | 0x01, STATUS (pb)); /* Some reset by writing 1 */
62 	parport_writeb (r & 0xfe, STATUS (pb)); /* Others by writing 0 */
63 	r = parport_gsc_read_status(pb);
64 
65 	return !(r & 0x01);
66 }
67 
68 /*
69  * Access functions.
70  *
71  * Most of these aren't static because they may be used by the
72  * parport_xxx_yyy macros.  extern __inline__ versions of several
73  * of these are in parport_gsc.h.
74  */
75 
parport_gsc_init_state(struct pardevice * dev,struct parport_state * s)76 void parport_gsc_init_state(struct pardevice *dev, struct parport_state *s)
77 {
78 	s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
79 }
80 
parport_gsc_save_state(struct parport * p,struct parport_state * s)81 void parport_gsc_save_state(struct parport *p, struct parport_state *s)
82 {
83 	s->u.pc.ctr = parport_readb (CONTROL (p));
84 }
85 
parport_gsc_restore_state(struct parport * p,struct parport_state * s)86 void parport_gsc_restore_state(struct parport *p, struct parport_state *s)
87 {
88 	parport_writeb (s->u.pc.ctr, CONTROL (p));
89 }
90 
91 struct parport_operations parport_gsc_ops =
92 {
93 	.write_data	= parport_gsc_write_data,
94 	.read_data	= parport_gsc_read_data,
95 
96 	.write_control	= parport_gsc_write_control,
97 	.read_control	= parport_gsc_read_control,
98 	.frob_control	= parport_gsc_frob_control,
99 
100 	.read_status	= parport_gsc_read_status,
101 
102 	.enable_irq	= parport_gsc_enable_irq,
103 	.disable_irq	= parport_gsc_disable_irq,
104 
105 	.data_forward	= parport_gsc_data_forward,
106 	.data_reverse	= parport_gsc_data_reverse,
107 
108 	.init_state	= parport_gsc_init_state,
109 	.save_state	= parport_gsc_save_state,
110 	.restore_state	= parport_gsc_restore_state,
111 
112 	.epp_write_data	= parport_ieee1284_epp_write_data,
113 	.epp_read_data	= parport_ieee1284_epp_read_data,
114 	.epp_write_addr	= parport_ieee1284_epp_write_addr,
115 	.epp_read_addr	= parport_ieee1284_epp_read_addr,
116 
117 	.ecp_write_data	= parport_ieee1284_ecp_write_data,
118 	.ecp_read_data	= parport_ieee1284_ecp_read_data,
119 	.ecp_write_addr	= parport_ieee1284_ecp_write_addr,
120 
121 	.compat_write_data 	= parport_ieee1284_write_compat,
122 	.nibble_read_data	= parport_ieee1284_read_nibble,
123 	.byte_read_data		= parport_ieee1284_read_byte,
124 
125 	.owner		= THIS_MODULE,
126 };
127 
128 /* --- Mode detection ------------------------------------- */
129 
130 /*
131  * Checks for port existence, all ports support SPP MODE
132  */
parport_SPP_supported(struct parport * pb)133 static int parport_SPP_supported(struct parport *pb)
134 {
135 	unsigned char r, w;
136 
137 	/*
138 	 * first clear an eventually pending EPP timeout
139 	 * I (sailer@ife.ee.ethz.ch) have an SMSC chipset
140 	 * that does not even respond to SPP cycles if an EPP
141 	 * timeout is pending
142 	 */
143 	clear_epp_timeout(pb);
144 
145 	/* Do a simple read-write test to make sure the port exists. */
146 	w = 0xc;
147 	parport_writeb (w, CONTROL (pb));
148 
149 	/* Is there a control register that we can read from?  Some
150 	 * ports don't allow reads, so read_control just returns a
151 	 * software copy. Some ports _do_ allow reads, so bypass the
152 	 * software copy here.  In addition, some bits aren't
153 	 * writable. */
154 	r = parport_readb (CONTROL (pb));
155 	if ((r & 0xf) == w) {
156 		w = 0xe;
157 		parport_writeb (w, CONTROL (pb));
158 		r = parport_readb (CONTROL (pb));
159 		parport_writeb (0xc, CONTROL (pb));
160 		if ((r & 0xf) == w)
161 			return PARPORT_MODE_PCSPP;
162 	}
163 
164 	/* Try the data register.  The data lines aren't tri-stated at
165 	 * this stage, so we expect back what we wrote. */
166 	w = 0xaa;
167 	parport_gsc_write_data (pb, w);
168 	r = parport_gsc_read_data (pb);
169 	if (r == w) {
170 		w = 0x55;
171 		parport_gsc_write_data (pb, w);
172 		r = parport_gsc_read_data (pb);
173 		if (r == w)
174 			return PARPORT_MODE_PCSPP;
175 	}
176 
177 	return 0;
178 }
179 
180 /* Detect PS/2 support.
181  *
182  * Bit 5 (0x20) sets the PS/2 data direction; setting this high
183  * allows us to read data from the data lines.  In theory we would get back
184  * 0xff but any peripheral attached to the port may drag some or all of the
185  * lines down to zero.  So if we get back anything that isn't the contents
186  * of the data register we deem PS/2 support to be present.
187  *
188  * Some SPP ports have "half PS/2" ability - you can't turn off the line
189  * drivers, but an external peripheral with sufficiently beefy drivers of
190  * its own can overpower them and assert its own levels onto the bus, from
191  * where they can then be read back as normal.  Ports with this property
192  * and the right type of device attached are likely to fail the SPP test,
193  * (as they will appear to have stuck bits) and so the fact that they might
194  * be misdetected here is rather academic.
195  */
196 
parport_PS2_supported(struct parport * pb)197 static int parport_PS2_supported(struct parport *pb)
198 {
199 	int ok = 0;
200 
201 	clear_epp_timeout(pb);
202 
203 	/* try to tri-state the buffer */
204 	parport_gsc_data_reverse (pb);
205 
206 	parport_gsc_write_data(pb, 0x55);
207 	if (parport_gsc_read_data(pb) != 0x55) ok++;
208 
209 	parport_gsc_write_data(pb, 0xaa);
210 	if (parport_gsc_read_data(pb) != 0xaa) ok++;
211 
212 	/* cancel input mode */
213 	parport_gsc_data_forward (pb);
214 
215 	if (ok) {
216 		pb->modes |= PARPORT_MODE_TRISTATE;
217 	} else {
218 		struct parport_gsc_private *priv = pb->private_data;
219 		priv->ctr_writable &= ~0x20;
220 	}
221 
222 	return ok;
223 }
224 
225 
226 /* --- Initialisation code -------------------------------- */
227 
parport_gsc_probe_port(unsigned long base,unsigned long base_hi,int irq,struct parisc_device * padev)228 static struct parport *parport_gsc_probe_port(unsigned long base,
229 				       unsigned long base_hi, int irq,
230 				       struct parisc_device *padev)
231 {
232 	struct parport_gsc_private *priv;
233 	struct parport_operations *ops;
234 	struct parport tmp;
235 	struct parport *p = &tmp;
236 
237 	priv = kzalloc (sizeof (struct parport_gsc_private), GFP_KERNEL);
238 	if (!priv) {
239 		printk(KERN_DEBUG "parport (0x%lx): no memory!\n", base);
240 		return NULL;
241 	}
242 	ops = kmemdup(&parport_gsc_ops, sizeof(struct parport_operations),
243 		      GFP_KERNEL);
244 	if (!ops) {
245 		printk(KERN_DEBUG "parport (0x%lx): no memory for ops!\n",
246 		       base);
247 		kfree (priv);
248 		return NULL;
249 	}
250 	priv->ctr = 0xc;
251 	priv->ctr_writable = 0xff;
252 	p->base = base;
253 	p->base_hi = base_hi;
254 	p->irq = irq;
255 	p->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT;
256 	p->ops = ops;
257 	p->private_data = priv;
258 	p->physport = p;
259 	if (!parport_SPP_supported (p)) {
260 		/* No port. */
261 		kfree (priv);
262 		kfree(ops);
263 		return NULL;
264 	}
265 	parport_PS2_supported (p);
266 
267 	if (!(p = parport_register_port(base, PARPORT_IRQ_NONE,
268 					PARPORT_DMA_NONE, ops))) {
269 		kfree (priv);
270 		kfree (ops);
271 		return NULL;
272 	}
273 
274 	p->dev = &padev->dev;
275 	p->base_hi = base_hi;
276 	p->modes = tmp.modes;
277 	p->size = (p->modes & PARPORT_MODE_EPP)?8:3;
278 	p->private_data = priv;
279 
280 	pr_info("%s: PC-style at 0x%lx", p->name, p->base);
281 	p->irq = irq;
282 	if (p->irq == PARPORT_IRQ_AUTO) {
283 		p->irq = PARPORT_IRQ_NONE;
284 	}
285 	if (p->irq != PARPORT_IRQ_NONE)
286 		pr_cont(", irq %d", p->irq);
287 
288 	pr_cont(" [");
289 #define printmode(x)							\
290 do {									\
291 	if (p->modes & PARPORT_MODE_##x)				\
292 		pr_cont("%s%s", f++ ? "," : "", #x);			\
293 } while (0)
294 	{
295 		int f = 0;
296 		printmode(PCSPP);
297 		printmode(TRISTATE);
298 		printmode(COMPAT);
299 		printmode(EPP);
300 //		printmode(ECP);
301 //		printmode(DMA);
302 	}
303 #undef printmode
304 	pr_cont("]\n");
305 
306 	if (p->irq != PARPORT_IRQ_NONE) {
307 		if (request_irq (p->irq, parport_irq_handler,
308 				 0, p->name, p)) {
309 			pr_warn("%s: irq %d in use, resorting to polled operation\n",
310 				p->name, p->irq);
311 			p->irq = PARPORT_IRQ_NONE;
312 		}
313 	}
314 
315 	/* Done probing.  Now put the port into a sensible start-up state. */
316 
317 	parport_gsc_write_data(p, 0);
318 	parport_gsc_data_forward (p);
319 
320 	/* Now that we've told the sharing engine about the port, and
321 	   found out its characteristics, let the high-level drivers
322 	   know about it. */
323 	parport_announce_port (p);
324 
325 	return p;
326 }
327 
328 
329 #define PARPORT_GSC_OFFSET 0x800
330 
331 static int parport_count;
332 
parport_init_chip(struct parisc_device * dev)333 static int __init parport_init_chip(struct parisc_device *dev)
334 {
335 	struct parport *p;
336 	unsigned long port;
337 
338 	if (!dev->irq) {
339 		pr_warn("IRQ not found for parallel device at 0x%llx\n",
340 			(unsigned long long)dev->hpa.start);
341 		return -ENODEV;
342 	}
343 
344 	port = dev->hpa.start + PARPORT_GSC_OFFSET;
345 
346 	/* some older machines with ASP-chip don't support
347 	 * the enhanced parport modes.
348 	 */
349 	if (boot_cpu_data.cpu_type > pcxt && !pdc_add_valid(port+4)) {
350 
351 		/* Initialize bidirectional-mode (0x10) & data-tranfer-mode #1 (0x20) */
352 		pr_info("%s: initialize bidirectional-mode\n", __func__);
353 		parport_writeb ( (0x10 + 0x20), port + 4);
354 
355 	} else {
356 		pr_info("%s: enhanced parport-modes not supported\n", __func__);
357 	}
358 
359 	p = parport_gsc_probe_port(port, 0, dev->irq, dev);
360 	if (p)
361 		parport_count++;
362 	dev_set_drvdata(&dev->dev, p);
363 
364 	return 0;
365 }
366 
parport_remove_chip(struct parisc_device * dev)367 static void __exit parport_remove_chip(struct parisc_device *dev)
368 {
369 	struct parport *p = dev_get_drvdata(&dev->dev);
370 	if (p) {
371 		struct parport_operations *ops = p->ops;
372 		parport_remove_port(p);
373 		if (p->irq != PARPORT_IRQ_NONE)
374 			free_irq(p->irq, p);
375 		kfree (p->private_data);
376 		parport_put_port(p);
377 		kfree (ops); /* hope no-one cached it */
378 	}
379 }
380 
381 static const struct parisc_device_id parport_tbl[] __initconst = {
382 	{ HPHW_FIO, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x74 },
383 	{ 0, }
384 };
385 
386 MODULE_DEVICE_TABLE(parisc, parport_tbl);
387 
388 static struct parisc_driver parport_driver __refdata = {
389 	.name		= "Parallel",
390 	.id_table	= parport_tbl,
391 	.probe		= parport_init_chip,
392 	.remove		= __exit_p(parport_remove_chip),
393 };
394 
parport_gsc_init(void)395 int parport_gsc_init(void)
396 {
397 	return register_parisc_driver(&parport_driver);
398 }
399 
parport_gsc_exit(void)400 static void parport_gsc_exit(void)
401 {
402 	unregister_parisc_driver(&parport_driver);
403 }
404 
405 module_init(parport_gsc_init);
406 module_exit(parport_gsc_exit);
407