ioc4.c 12 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2005 Silicon Graphics, Inc.  All Rights Reserved.
 */

9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
/* This file contains the master driver module for use by SGI IOC4 subdrivers.
 *
 * It allocates any resources shared between multiple subdevices, and
 * provides accessor functions (where needed) and the like for those
 * resources.  It also provides a mechanism for the subdevice modules
 * to support loading and unloading.
 *
 * Non-shared resources (e.g. external interrupt A_INT_OUT register page
 * alias, serial port and UART registers) are handled by the subdevice
 * modules themselves.
 *
 * This is all necessary because IOC4 is not implemented as a multi-function
 * PCI device, but an amalgamation of disparate registers for several
 * types of device (ATA, serial, external interrupts).  The normal
 * resource management in the kernel doesn't have quite the right interfaces
 * to handle this situation (e.g. multiple modules can't claim the same
 * PCI ID), thus this IOC4 master module.
Linus Torvalds's avatar
Linus Torvalds committed
26
27
28
29
30
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/pci.h>
31
#include <linux/ioc4.h>
32
33
#include <linux/mmtimer.h>
#include <linux/rtc.h>
Jes Sorensen's avatar
Jes Sorensen committed
34
#include <linux/mutex.h>
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
#include <asm/sn/addrs.h>
#include <asm/sn/clksupport.h>
#include <asm/sn/shub_mmr.h>

/***************
 * Definitions *
 ***************/

/* Tweakable values */

/* PCI bus speed detection/calibration */
#define IOC4_CALIBRATE_COUNT 63	/* Calibration cycle period */
#define IOC4_CALIBRATE_CYCLES 256	/* Average over this many cycles */
#define IOC4_CALIBRATE_DISCARD 2	/* Discard first few cycles */
#define IOC4_CALIBRATE_LOW_MHZ 25	/* Lower bound on bus speed sanity */
#define IOC4_CALIBRATE_HIGH_MHZ 75	/* Upper bound on bus speed sanity */
#define IOC4_CALIBRATE_DEFAULT_MHZ 66	/* Assumed if sanity check fails */
Linus Torvalds's avatar
Linus Torvalds committed
52

53
54
55
/************************
 * Submodule management *
 ************************/
Linus Torvalds's avatar
Linus Torvalds committed
56

Jes Sorensen's avatar
Jes Sorensen committed
57
static DEFINE_MUTEX(ioc4_mutex);
58

Jes Sorensen's avatar
Jes Sorensen committed
59
static LIST_HEAD(ioc4_devices);
60
61
62
63
64
65
66
67
static LIST_HEAD(ioc4_submodules);

/* Register an IOC4 submodule */
int
ioc4_register_submodule(struct ioc4_submodule *is)
{
	struct ioc4_driver_data *idd;

Jes Sorensen's avatar
Jes Sorensen committed
68
	mutex_lock(&ioc4_mutex);
69
70
71
72
	list_add(&is->is_list, &ioc4_submodules);

	/* Initialize submodule for each IOC4 */
	if (!is->is_probe)
Jes Sorensen's avatar
Jes Sorensen committed
73
		goto out;
74
75
76
77
78
79
80
81
82
83

	list_for_each_entry(idd, &ioc4_devices, idd_list) {
		if (is->is_probe(idd)) {
			printk(KERN_WARNING
			       "%s: IOC4 submodule %s probe failed "
			       "for pci_dev %s",
			       __FUNCTION__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
Jes Sorensen's avatar
Jes Sorensen committed
84
85
 out:
	mutex_unlock(&ioc4_mutex);
86
87
88
89
90
91
	return 0;
}

/* Unregister an IOC4 submodule */
void
ioc4_unregister_submodule(struct ioc4_submodule *is)
Linus Torvalds's avatar
Linus Torvalds committed
92
{
93
94
	struct ioc4_driver_data *idd;

Jes Sorensen's avatar
Jes Sorensen committed
95
	mutex_lock(&ioc4_mutex);
96
97
98
99
	list_del(&is->is_list);

	/* Remove submodule for each IOC4 */
	if (!is->is_remove)
Jes Sorensen's avatar
Jes Sorensen committed
100
		goto out;
101
102
103
104
105
106
107
108
109
110

	list_for_each_entry(idd, &ioc4_devices, idd_list) {
		if (is->is_remove(idd)) {
			printk(KERN_WARNING
			       "%s: IOC4 submodule %s remove failed "
			       "for pci_dev %s.\n",
			       __FUNCTION__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
Jes Sorensen's avatar
Jes Sorensen committed
111
112
 out:
	mutex_unlock(&ioc4_mutex);
113
114
115
116
117
118
}

/*********************
 * Device management *
 *********************/

119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
#define IOC4_CALIBRATE_LOW_LIMIT \
	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_LOW_MHZ)
#define IOC4_CALIBRATE_HIGH_LIMIT \
	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_HIGH_MHZ)
#define IOC4_CALIBRATE_DEFAULT \
	(1000*IOC4_EXTINT_COUNT_DIVISOR/IOC4_CALIBRATE_DEFAULT_MHZ)

#define IOC4_CALIBRATE_END \
	(IOC4_CALIBRATE_CYCLES + IOC4_CALIBRATE_DISCARD)

#define IOC4_INT_OUT_MODE_TOGGLE 0x7	/* Toggle INT_OUT every COUNT+1 ticks */

/* Determines external interrupt output clock period of the PCI bus an
 * IOC4 is attached to.  This value can be used to determine the PCI
 * bus speed.
 *
 * IOC4 has a design feature that various internal timers are derived from
 * the PCI bus clock.  This causes IOC4 device drivers to need to take the
 * bus speed into account when setting various register values (e.g. INT_OUT
 * register COUNT field, UART divisors, etc).  Since this information is
 * needed by several subdrivers, it is determined by the main IOC4 driver,
 * even though the following code utilizes external interrupt registers
 * to perform the speed calculation.
 */
static void
ioc4_clock_calibrate(struct ioc4_driver_data *idd)
{
	extern unsigned long sn_rtc_cycles_per_second;
	union ioc4_int_out int_out;
	union ioc4_gpcr gpcr;
	unsigned int state, last_state = 1;
	uint64_t start = 0, end, period;
	unsigned int count = 0;

	/* Enable output */
	gpcr.raw = 0;
	gpcr.fields.dir = IOC4_GPCR_DIR_0;
	gpcr.fields.int_out_en = 1;
	writel(gpcr.raw, &idd->idd_misc_regs->gpcr_s.raw);

	/* Reset to power-on state */
	writel(0, &idd->idd_misc_regs->int_out.raw);
	mmiowb();

	printk(KERN_INFO
	       "%s: Calibrating PCI bus speed "
	       "for pci_dev %s ... ", __FUNCTION__, pci_name(idd->idd_pdev));
	/* Set up square wave */
	int_out.raw = 0;
	int_out.fields.count = IOC4_CALIBRATE_COUNT;
	int_out.fields.mode = IOC4_INT_OUT_MODE_TOGGLE;
	int_out.fields.diag = 0;
	writel(int_out.raw, &idd->idd_misc_regs->int_out.raw);
	mmiowb();

	/* Check square wave period averaged over some number of cycles */
	do {
		int_out.raw = readl(&idd->idd_misc_regs->int_out.raw);
		state = int_out.fields.int_out;
		if (!last_state && state) {
			count++;
			if (count == IOC4_CALIBRATE_END) {
				end = rtc_time();
				break;
			} else if (count == IOC4_CALIBRATE_DISCARD)
				start = rtc_time();
		}
		last_state = state;
	} while (1);

	/* Calculation rearranged to preserve intermediate precision.
	 * Logically:
	 * 1. "end - start" gives us number of RTC cycles over all the
	 *    square wave cycles measured.
	 * 2. Divide by number of square wave cycles to get number of
	 *    RTC cycles per square wave cycle.
	 * 3. Divide by 2*(int_out.fields.count+1), which is the formula
	 *    by which the IOC4 generates the square wave, to get the
	 *    number of RTC cycles per IOC4 INT_OUT count.
	 * 4. Divide by sn_rtc_cycles_per_second to get seconds per
	 *    count.
	 * 5. Multiply by 1E9 to get nanoseconds per count.
	 */
	period = ((end - start) * 1000000000) /
	    (IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1)
	     * sn_rtc_cycles_per_second);

	/* Bounds check the result. */
	if (period > IOC4_CALIBRATE_LOW_LIMIT ||
	    period < IOC4_CALIBRATE_HIGH_LIMIT) {
		printk("failed. Assuming PCI clock ticks are %d ns.\n",
		       IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
		period = IOC4_CALIBRATE_DEFAULT;
	} else {
		printk("succeeded. PCI clock ticks are %ld ns.\n",
		       period / IOC4_EXTINT_COUNT_DIVISOR);
	}

	/* Remember results.  We store the extint clock period rather
	 * than the PCI clock period so that greater precision is
	 * retained.  Divide by IOC4_EXTINT_COUNT_DIVISOR to get
	 * PCI clock period.
	 */
	idd->count_period = period;
}

225
226
227
228
229
230
231
/* Adds a new instance of an IOC4 card */
static int
ioc4_probe(struct pci_dev *pdev, const struct pci_device_id *pci_id)
{
	struct ioc4_driver_data *idd;
	struct ioc4_submodule *is;
	uint32_t pcmd;
Linus Torvalds's avatar
Linus Torvalds committed
232
233
	int ret;

234
	/* Enable IOC4 and take ownership of it */
Linus Torvalds's avatar
Linus Torvalds committed
235
236
	if ((ret = pci_enable_device(pdev))) {
		printk(KERN_WARNING
237
238
239
		       "%s: Failed to enable IOC4 device for pci_dev %s.\n",
		       __FUNCTION__, pci_name(pdev));
		goto out;
Linus Torvalds's avatar
Linus Torvalds committed
240
241
242
	}
	pci_set_master(pdev);

243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
	/* Set up per-IOC4 data */
	idd = kmalloc(sizeof(struct ioc4_driver_data), GFP_KERNEL);
	if (!idd) {
		printk(KERN_WARNING
		       "%s: Failed to allocate IOC4 data for pci_dev %s.\n",
		       __FUNCTION__, pci_name(pdev));
		ret = -ENODEV;
		goto out_idd;
	}
	idd->idd_pdev = pdev;
	idd->idd_pci_id = pci_id;

	/* Map IOC4 misc registers.  These are shared between subdevices
	 * so the main IOC4 module manages them.
	 */
	idd->idd_bar0 = pci_resource_start(idd->idd_pdev, 0);
	if (!idd->idd_bar0) {
		printk(KERN_WARNING
		       "%s: Unable to find IOC4 misc resource "
		       "for pci_dev %s.\n",
		       __FUNCTION__, pci_name(idd->idd_pdev));
		ret = -ENODEV;
		goto out_pci;
	}
	if (!request_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs),
			    "ioc4_misc")) {
		printk(KERN_WARNING
		       "%s: Unable to request IOC4 misc region "
		       "for pci_dev %s.\n",
		       __FUNCTION__, pci_name(idd->idd_pdev));
		ret = -ENODEV;
		goto out_pci;
	}
	idd->idd_misc_regs = ioremap(idd->idd_bar0,
				     sizeof(struct ioc4_misc_regs));
	if (!idd->idd_misc_regs) {
		printk(KERN_WARNING
		       "%s: Unable to remap IOC4 misc region "
		       "for pci_dev %s.\n",
		       __FUNCTION__, pci_name(idd->idd_pdev));
		ret = -ENODEV;
		goto out_misc_region;
	}

	/* Failsafe portion of per-IOC4 initialization */

	/* Initialize IOC4 */
	pci_read_config_dword(idd->idd_pdev, PCI_COMMAND, &pcmd);
	pci_write_config_dword(idd->idd_pdev, PCI_COMMAND,
			       pcmd | PCI_COMMAND_PARITY | PCI_COMMAND_SERR);

294
295
296
	/* Determine PCI clock */
	ioc4_clock_calibrate(idd);

297
298
299
300
301
302
303
304
305
306
307
308
309
310
	/* Disable/clear all interrupts.  Need to do this here lest
	 * one submodule request the shared IOC4 IRQ, but interrupt
	 * is generated by a different subdevice.
	 */
	/* Disable */
	writel(~0, &idd->idd_misc_regs->other_iec.raw);
	writel(~0, &idd->idd_misc_regs->sio_iec);
	/* Clear (i.e. acknowledge) */
	writel(~0, &idd->idd_misc_regs->other_ir.raw);
	writel(~0, &idd->idd_misc_regs->sio_ir);

	/* Track PCI-device specific data */
	idd->idd_serial_data = NULL;
	pci_set_drvdata(idd->idd_pdev, idd);
Jes Sorensen's avatar
Jes Sorensen committed
311
312

	mutex_lock(&ioc4_mutex);
313
314
315
316
317
318
319
320
321
322
323
324
	list_add(&idd->idd_list, &ioc4_devices);

	/* Add this IOC4 to all submodules */
	list_for_each_entry(is, &ioc4_submodules, is_list) {
		if (is->is_probe && is->is_probe(idd)) {
			printk(KERN_WARNING
			       "%s: IOC4 submodule 0x%s probe failed "
			       "for pci_dev %s.\n",
			       __FUNCTION__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
Jes Sorensen's avatar
Jes Sorensen committed
325
	mutex_unlock(&ioc4_mutex);
326
327
328
329
330
331
332
333
334
335
336

	return 0;

out_misc_region:
	release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
out_pci:
	kfree(idd);
out_idd:
	pci_disable_device(pdev);
out:
	return ret;
Linus Torvalds's avatar
Linus Torvalds committed
337
338
}

339
340
341
342
343
344
345
346
347
348
/* Removes a particular instance of an IOC4 card. */
static void
ioc4_remove(struct pci_dev *pdev)
{
	struct ioc4_submodule *is;
	struct ioc4_driver_data *idd;

	idd = pci_get_drvdata(pdev);

	/* Remove this IOC4 from all submodules */
Jes Sorensen's avatar
Jes Sorensen committed
349
	mutex_lock(&ioc4_mutex);
350
351
352
353
354
355
356
357
358
	list_for_each_entry(is, &ioc4_submodules, is_list) {
		if (is->is_remove && is->is_remove(idd)) {
			printk(KERN_WARNING
			       "%s: IOC4 submodule 0x%s remove failed "
			       "for pci_dev %s.\n",
			       __FUNCTION__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
Jes Sorensen's avatar
Jes Sorensen committed
359
	mutex_unlock(&ioc4_mutex);
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374

	/* Release resources */
	iounmap(idd->idd_misc_regs);
	if (!idd->idd_bar0) {
		printk(KERN_WARNING
		       "%s: Unable to get IOC4 misc mapping for pci_dev %s. "
		       "Device removal may be incomplete.\n",
		       __FUNCTION__, pci_name(idd->idd_pdev));
	}
	release_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));

	/* Disable IOC4 and relinquish */
	pci_disable_device(pdev);

	/* Remove and free driver data */
Jes Sorensen's avatar
Jes Sorensen committed
375
	mutex_lock(&ioc4_mutex);
376
	list_del(&idd->idd_list);
Jes Sorensen's avatar
Jes Sorensen committed
377
	mutex_unlock(&ioc4_mutex);
378
379
380
381
	kfree(idd);
}

static struct pci_device_id ioc4_id_table[] = {
Linus Torvalds's avatar
Linus Torvalds committed
382
383
384
385
386
	{PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
	 PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
	{0}
};

387
388
389
390
391
static struct pci_driver __devinitdata ioc4_driver = {
	.name = "IOC4",
	.id_table = ioc4_id_table,
	.probe = ioc4_probe,
	.remove = ioc4_remove,
Linus Torvalds's avatar
Linus Torvalds committed
392
393
};

394
395
396
397
398
399
400
401
402
MODULE_DEVICE_TABLE(pci, ioc4_id_table);

/*********************
 * Module management *
 *********************/

/* Module load */
static int __devinit
ioc4_init(void)
Linus Torvalds's avatar
Linus Torvalds committed
403
{
404
405
	return pci_register_driver(&ioc4_driver);
}
Linus Torvalds's avatar
Linus Torvalds committed
406

407
408
409
410
411
/* Module unload */
static void __devexit
ioc4_exit(void)
{
	pci_unregister_driver(&ioc4_driver);
Linus Torvalds's avatar
Linus Torvalds committed
412
413
}

414
415
416
417
418
module_init(ioc4_init);
module_exit(ioc4_exit);

MODULE_AUTHOR("Brent Casavant - Silicon Graphics, Inc. <bcasavan@sgi.com>");
MODULE_DESCRIPTION("PCI driver master module for SGI IOC4 Base-IO Card");
Linus Torvalds's avatar
Linus Torvalds committed
419
MODULE_LICENSE("GPL");
420
421
422

EXPORT_SYMBOL(ioc4_register_submodule);
EXPORT_SYMBOL(ioc4_unregister_submodule);