aboutsummaryrefslogtreecommitdiff
path: root/drivers/misc/ioc4.c
blob: 794a7e002c879efa39bcacbd942d695104770d8b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
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
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
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
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/*
 * 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) 2005-2006 Silicon Graphics, Inc.  All Rights Reserved.
 */

/* 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.
 */

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/ioc4.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/time.h>
#include <asm/io.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 */

/************************
 * Submodule management *
 ************************/

static DEFINE_MUTEX(ioc4_mutex);

static LIST_HEAD(ioc4_devices);
static LIST_HEAD(ioc4_submodules);

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

	mutex_lock(&ioc4_mutex);
	list_add(&is->is_list, &ioc4_submodules);

	/* Initialize submodule for each IOC4 */
	if (!is->is_probe)
		goto out;

	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",
			       __func__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
 out:
	mutex_unlock(&ioc4_mutex);
	return 0;
}

/* Unregister an IOC4 submodule */
void
ioc4_unregister_submodule(struct ioc4_submodule *is)
{
	struct ioc4_driver_data *idd;

	mutex_lock(&ioc4_mutex);
	list_del(&is->is_list);

	/* Remove submodule for each IOC4 */
	if (!is->is_remove)
		goto out;

	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",
			       __func__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
 out:
	mutex_unlock(&ioc4_mutex);
}

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

#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 __devinit
ioc4_clock_calibrate(struct ioc4_driver_data *idd)
{
	union ioc4_int_out int_out;
	union ioc4_gpcr gpcr;
	unsigned int state, last_state = 1;
	struct timespec start_ts, end_ts;
	uint64_t start, 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();

	/* 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) {
				ktime_get_ts(&end_ts);
				break;
			} else if (count == IOC4_CALIBRATE_DISCARD)
				ktime_get_ts(&start_ts);
		}
		last_state = state;
	} while (1);

	/* Calculation rearranged to preserve intermediate precision.
	 * Logically:
	 * 1. "end - start" gives us the measurement period over all
	 *    the square wave cycles.
	 * 2. Divide by number of square wave cycles to get the period
	 *    of a 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
	 *    period of an IOC4 INT_OUT count.
	 */
	end = end_ts.tv_sec * NSEC_PER_SEC + end_ts.tv_nsec;
	start = start_ts.tv_sec * NSEC_PER_SEC + start_ts.tv_nsec;
	period = (end - start) /
		(IOC4_CALIBRATE_CYCLES * 2 * (IOC4_CALIBRATE_COUNT + 1));

	/* Bounds check the result. */
	if (period > IOC4_CALIBRATE_LOW_LIMIT ||
	    period < IOC4_CALIBRATE_HIGH_LIMIT) {
		printk(KERN_INFO
		       "IOC4 %s: Clock calibration failed.  Assuming"
		       "PCI clock is %d ns.\n",
		       pci_name(idd->idd_pdev),
		       IOC4_CALIBRATE_DEFAULT / IOC4_EXTINT_COUNT_DIVISOR);
		period = IOC4_CALIBRATE_DEFAULT;
	} else {
		u64 ns = period;

		do_div(ns, IOC4_EXTINT_COUNT_DIVISOR);
		printk(KERN_DEBUG
		       "IOC4 %s: PCI clock is %llu ns.\n",
		       pci_name(idd->idd_pdev), (unsigned long long)ns);
	}

	/* 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;
}

/* There are three variants of IOC4 cards: IO9, IO10, and PCI-RT.
 * Each brings out different combinations of IOC4 signals, thus.
 * the IOC4 subdrivers need to know to which we're attached.
 *
 * We look for the presence of a SCSI (IO9) or SATA (IO10) controller
 * on the same PCI bus at slot number 3 to differentiate IO9 from IO10.
 * If neither is present, it's a PCI-RT.
 */
static unsigned int __devinit
ioc4_variant(struct ioc4_driver_data *idd)
{
	struct pci_dev *pdev = NULL;
	int found = 0;

	/* IO9: Look for a QLogic ISP 12160 at the same bus and slot 3. */
	do {
		pdev = pci_get_device(PCI_VENDOR_ID_QLOGIC,
				      PCI_DEVICE_ID_QLOGIC_ISP12160, pdev);
		if (pdev &&
		    idd->idd_pdev->bus->number == pdev->bus->number &&
		    3 == PCI_SLOT(pdev->devfn))
			found = 1;
	} while (pdev && !found);
	if (NULL != pdev) {
		pci_dev_put(pdev);
		return IOC4_VARIANT_IO9;
	}

	/* IO10: Look for a Vitesse VSC 7174 at the same bus and slot 3. */
	pdev = NULL;
	do {
		pdev = pci_get_device(PCI_VENDOR_ID_VITESSE,
				      PCI_DEVICE_ID_VITESSE_VSC7174, pdev);
		if (pdev &&
		    idd->idd_pdev->bus->number == pdev->bus->number &&
		    3 == PCI_SLOT(pdev->devfn))
			found = 1;
	} while (pdev && !found);
	if (NULL != pdev) {
		pci_dev_put(pdev);
		return IOC4_VARIANT_IO10;
	}

	/* PCI-RT: No SCSI/SATA controller will be present */
	return IOC4_VARIANT_PCI_RT;
}

static void
ioc4_load_modules(struct work_struct *work)
{
	request_module("sgiioc4");
}

static DECLARE_WORK(ioc4_load_modules_work, ioc4_load_modules);

/* Adds a new instance of an IOC4 card */
static int __devinit
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;
	int ret;

	/* Enable IOC4 and take ownership of it */
	if ((ret = pci_enable_device(pdev))) {
		printk(KERN_WARNING
		       "%s: Failed to enable IOC4 device for pci_dev %s.\n",
		       __func__, pci_name(pdev));
		goto out;
	}
	pci_set_master(pdev);

	/* 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",
		       __func__, 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",
		       __func__, pci_name(idd->idd_pdev));
		ret = -ENODEV;
		goto out_pci;
	}
	if (!request_mem_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",
		       __func__, 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",
		       __func__, pci_name(idd->idd_pdev));
		ret = -ENODEV;
		goto out_misc_region;
	}

	/* Failsafe portion of per-IOC4 initialization */

	/* Detect card variant */
	idd->idd_variant = ioc4_variant(idd);
	printk(KERN_INFO "IOC4 %s: %s card detected.\n", pci_name(pdev),
	       idd->idd_variant == IOC4_VARIANT_IO9 ? "IO9" :
	       idd->idd_variant == IOC4_VARIANT_PCI_RT ? "PCI-RT" :
	       idd->idd_variant == IOC4_VARIANT_IO10 ? "IO10" : "unknown");

	/* 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);

	/* Determine PCI clock */
	ioc4_clock_calibrate(idd);

	/* 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);

	mutex_lock(&ioc4_mutex);
	list_add_tail(&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",
			       __func__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
	mutex_unlock(&ioc4_mutex);

	/* Request sgiioc4 IDE driver on boards that bring that functionality
	 * off of IOC4.  The root filesystem may be hosted on a drive connected
	 * to IOC4, so we need to make sure the sgiioc4 driver is loaded as it
	 * won't be picked up by modprobes due to the ioc4 module owning the
	 * PCI device.
	 */
	if (idd->idd_variant != IOC4_VARIANT_PCI_RT) {
		/* Request the module from a work procedure as the modprobe
		 * goes out to a userland helper and that will hang if done
		 * directly from ioc4_probe().
		 */
		printk(KERN_INFO "IOC4 loading sgiioc4 submodule\n");
		schedule_work(&ioc4_load_modules_work);
	}

	return 0;

out_misc_region:
	release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));
out_pci:
	kfree(idd);
out_idd:
	pci_disable_device(pdev);
out:
	return ret;
}

/* Removes a particular instance of an IOC4 card. */
static void __devexit
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 */
	mutex_lock(&ioc4_mutex);
	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",
			       __func__, module_name(is->is_owner),
			       pci_name(idd->idd_pdev));
		}
	}
	mutex_unlock(&ioc4_mutex);

	/* 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",
		       __func__, pci_name(idd->idd_pdev));
	}
	release_mem_region(idd->idd_bar0, sizeof(struct ioc4_misc_regs));

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

	/* Remove and free driver data */
	mutex_lock(&ioc4_mutex);
	list_del(&idd->idd_list);
	mutex_unlock(&ioc4_mutex);
	kfree(idd);
}

static struct pci_device_id ioc4_id_table[] = {
	{PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC4, PCI_ANY_ID,
	 PCI_ANY_ID, 0x0b4000, 0xFFFFFF},
	{0}
};

static struct pci_driver ioc4_driver = {
	.name = "IOC4",
	.id_table = ioc4_id_table,
	.probe = ioc4_probe,
	.remove = ioc4_remove,
};

MODULE_DEVICE_TABLE(pci, ioc4_id_table);

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

/* Module load */
static int __init
ioc4_init(void)
{
	return pci_register_driver(&ioc4_driver);
}

/* Module unload */
static void __exit
ioc4_exit(void)
{
	/* Ensure ioc4_load_modules() has completed before exiting */
	flush_work(&ioc4_load_modules_work);
	pci_unregister_driver(&ioc4_driver);
}

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");
MODULE_LICENSE("GPL");

EXPORT_SYMBOL(ioc4_register_submodule);
EXPORT_SYMBOL(ioc4_unregister_submodule);