summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-amd-mp2-pci.c
blob: f57077a7448d1f7391104f4ea6ccfcd88561e417 (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
// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
/*
 * AMD MP2 PCIe communication driver
 *
 * Authors: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
 *          Elie Morisse <syniurge@gmail.com>
 */

#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>

#include "i2c-amd-mp2.h"

#include <linux/io-64-nonatomic-lo-hi.h>

static void amd_mp2_c2p_mutex_lock(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	/* there is only one data mailbox for two i2c adapters */
	mutex_lock(&privdata->c2p_lock);
	privdata->c2p_lock_busid = i2c_common->bus_id;
}

static void amd_mp2_c2p_mutex_unlock(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	if (unlikely(privdata->c2p_lock_busid != i2c_common->bus_id)) {
		pci_warn(privdata->pci_dev,
			 "bus %d attempting to unlock C2P locked by bus %d\n",
			 i2c_common->bus_id, privdata->c2p_lock_busid);
		return;
	}

	mutex_unlock(&privdata->c2p_lock);
}

static int amd_mp2_cmd(struct amd_i2c_common *i2c_common,
		       union i2c_cmd_base i2c_cmd_base)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	void __iomem *reg;

	i2c_common->reqcmd = i2c_cmd_base.s.i2c_cmd;

	reg = privdata->mmio + ((i2c_cmd_base.s.bus_id == 1) ?
				AMD_C2P_MSG1 : AMD_C2P_MSG0);
	writel(i2c_cmd_base.ul, reg);

	return 0;
}

int amd_mp2_bus_enable_set(struct amd_i2c_common *i2c_common, bool enable)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	union i2c_cmd_base i2c_cmd_base;

	pci_dbg(privdata->pci_dev, "id: %d\n", i2c_common->bus_id);

	i2c_cmd_base.ul = 0;
	i2c_cmd_base.s.i2c_cmd = enable ? i2c_enable : i2c_disable;
	i2c_cmd_base.s.bus_id = i2c_common->bus_id;
	i2c_cmd_base.s.i2c_speed = i2c_common->i2c_speed;

	amd_mp2_c2p_mutex_lock(i2c_common);

	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
}
EXPORT_SYMBOL_GPL(amd_mp2_bus_enable_set);

static void amd_mp2_cmd_rw_fill(struct amd_i2c_common *i2c_common,
				union i2c_cmd_base *i2c_cmd_base,
				enum i2c_cmd reqcmd)
{
	i2c_cmd_base->s.i2c_cmd = reqcmd;
	i2c_cmd_base->s.bus_id = i2c_common->bus_id;
	i2c_cmd_base->s.i2c_speed = i2c_common->i2c_speed;
	i2c_cmd_base->s.slave_addr = i2c_common->msg->addr;
	i2c_cmd_base->s.length = i2c_common->msg->len;
}

int amd_mp2_rw(struct amd_i2c_common *i2c_common, enum i2c_cmd reqcmd)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	union i2c_cmd_base i2c_cmd_base;

	amd_mp2_cmd_rw_fill(i2c_common, &i2c_cmd_base, reqcmd);
	amd_mp2_c2p_mutex_lock(i2c_common);

	if (i2c_common->msg->len <= 32) {
		i2c_cmd_base.s.mem_type = use_c2pmsg;
		if (reqcmd == i2c_write)
			memcpy_toio(privdata->mmio + AMD_C2P_MSG2,
				    i2c_common->msg->buf,
				    i2c_common->msg->len);
	} else {
		i2c_cmd_base.s.mem_type = use_dram;
		writeq((u64)i2c_common->dma_addr,
		       privdata->mmio + AMD_C2P_MSG2);
	}

	return amd_mp2_cmd(i2c_common, i2c_cmd_base);
}
EXPORT_SYMBOL_GPL(amd_mp2_rw);

static void amd_mp2_pci_check_rw_event(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;
	int len = i2c_common->eventval.r.length;
	u32 slave_addr = i2c_common->eventval.r.slave_addr;
	bool err = false;

	if (unlikely(len != i2c_common->msg->len)) {
		pci_err(pdev, "length %d in event doesn't match buffer length %d!\n",
			len, i2c_common->msg->len);
		err = true;
	}

	if (unlikely(slave_addr != i2c_common->msg->addr)) {
		pci_err(pdev, "unexpected slave address %x (expected: %x)!\n",
			slave_addr, i2c_common->msg->addr);
		err = true;
	}

	if (!err)
		i2c_common->cmd_success = true;
}

static void __amd_mp2_process_event(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;
	enum status_type sts = i2c_common->eventval.r.status;
	enum response_type res = i2c_common->eventval.r.response;
	int len = i2c_common->eventval.r.length;

	if (res != command_success) {
		if (res != command_failed)
			pci_err(pdev, "invalid response to i2c command!\n");
		return;
	}

	switch (i2c_common->reqcmd) {
	case i2c_read:
		if (sts == i2c_readcomplete_event) {
			amd_mp2_pci_check_rw_event(i2c_common);
			if (len <= 32)
				memcpy_fromio(i2c_common->msg->buf,
					      privdata->mmio + AMD_C2P_MSG2,
					      len);
		} else if (sts != i2c_readfail_event) {
			pci_err(pdev, "invalid i2c status after read (%d)!\n", sts);
		}
		break;
	case i2c_write:
		if (sts == i2c_writecomplete_event)
			amd_mp2_pci_check_rw_event(i2c_common);
		else if (sts != i2c_writefail_event)
			pci_err(pdev, "invalid i2c status after write (%d)!\n", sts);
		break;
	case i2c_enable:
		if (sts == i2c_busenable_complete)
			i2c_common->cmd_success = true;
		else if (sts != i2c_busenable_failed)
			pci_err(pdev, "invalid i2c status after bus enable (%d)!\n", sts);
		break;
	case i2c_disable:
		if (sts == i2c_busdisable_complete)
			i2c_common->cmd_success = true;
		else if (sts != i2c_busdisable_failed)
			pci_err(pdev, "invalid i2c status after bus disable (%d)!\n", sts);
		break;
	default:
		break;
	}
}

void amd_mp2_process_event(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;

	if (unlikely(i2c_common->reqcmd == i2c_none)) {
		pci_warn(pdev, "received msg but no cmd was sent (bus = %d)!\n",
			 i2c_common->bus_id);
		return;
	}

	__amd_mp2_process_event(i2c_common);

	i2c_common->reqcmd = i2c_none;
	amd_mp2_c2p_mutex_unlock(i2c_common);
}
EXPORT_SYMBOL_GPL(amd_mp2_process_event);

static irqreturn_t amd_mp2_irq_isr(int irq, void *dev)
{
	struct amd_mp2_dev *privdata = dev;
	struct pci_dev *pdev = privdata->pci_dev;
	struct amd_i2c_common *i2c_common;
	u32 val;
	unsigned int bus_id;
	void __iomem *reg;
	enum irqreturn ret = IRQ_NONE;

	for (bus_id = 0; bus_id < 2; bus_id++) {
		i2c_common = privdata->busses[bus_id];
		if (!i2c_common)
			continue;

		reg = privdata->mmio + ((bus_id == 0) ?
					AMD_P2C_MSG1 : AMD_P2C_MSG2);
		val = readl(reg);
		if (val != 0) {
			writel(0, reg);
			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
			i2c_common->eventval.ul = val;
			i2c_common->cmd_completion(i2c_common);

			ret = IRQ_HANDLED;
		}
	}

	if (ret != IRQ_HANDLED) {
		val = readl(privdata->mmio + AMD_P2C_MSG_INTEN);
		if (val != 0) {
			writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
			pci_warn(pdev, "received irq without message\n");
			ret = IRQ_HANDLED;
		}
	}

	return ret;
}

void amd_mp2_rw_timeout(struct amd_i2c_common *i2c_common)
{
	i2c_common->reqcmd = i2c_none;
	amd_mp2_c2p_mutex_unlock(i2c_common);
}
EXPORT_SYMBOL_GPL(amd_mp2_rw_timeout);

int amd_mp2_register_cb(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;
	struct pci_dev *pdev = privdata->pci_dev;

	if (i2c_common->bus_id > 1)
		return -EINVAL;

	if (privdata->busses[i2c_common->bus_id]) {
		pci_err(pdev, "Bus %d already taken!\n", i2c_common->bus_id);
		return -EINVAL;
	}

	privdata->busses[i2c_common->bus_id] = i2c_common;

	return 0;
}
EXPORT_SYMBOL_GPL(amd_mp2_register_cb);

int amd_mp2_unregister_cb(struct amd_i2c_common *i2c_common)
{
	struct amd_mp2_dev *privdata = i2c_common->mp2_dev;

	privdata->busses[i2c_common->bus_id] = NULL;

	return 0;
}
EXPORT_SYMBOL_GPL(amd_mp2_unregister_cb);

static void amd_mp2_clear_reg(struct amd_mp2_dev *privdata)
{
	int reg;

	for (reg = AMD_C2P_MSG0; reg <= AMD_C2P_MSG9; reg += 4)
		writel(0, privdata->mmio + reg);

	for (reg = AMD_P2C_MSG1; reg <= AMD_P2C_MSG2; reg += 4)
		writel(0, privdata->mmio + reg);
}

static int amd_mp2_pci_init(struct amd_mp2_dev *privdata,
			    struct pci_dev *pci_dev)
{
	int rc;

	pci_set_drvdata(pci_dev, privdata);

	rc = pcim_enable_device(pci_dev);
	if (rc) {
		pci_err(pci_dev, "Failed to enable MP2 PCI device\n");
		goto err_pci_enable;
	}

	rc = pcim_iomap_regions(pci_dev, 1 << 2, pci_name(pci_dev));
	if (rc) {
		pci_err(pci_dev, "I/O memory remapping failed\n");
		goto err_pci_enable;
	}
	privdata->mmio = pcim_iomap_table(pci_dev)[2];

	pci_set_master(pci_dev);

	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
	if (rc)
		goto err_dma_mask;

	/* Set up intx irq */
	writel(0, privdata->mmio + AMD_P2C_MSG_INTEN);
	pci_intx(pci_dev, 1);
	rc = devm_request_irq(&pci_dev->dev, pci_dev->irq, amd_mp2_irq_isr,
			      IRQF_SHARED, dev_name(&pci_dev->dev), privdata);
	if (rc)
		pci_err(pci_dev, "Failure requesting irq %i: %d\n",
			pci_dev->irq, rc);

	return rc;

err_dma_mask:
	pci_clear_master(pci_dev);
err_pci_enable:
	pci_set_drvdata(pci_dev, NULL);
	return rc;
}

static int amd_mp2_pci_probe(struct pci_dev *pci_dev,
			     const struct pci_device_id *id)
{
	struct amd_mp2_dev *privdata;
	int rc;

	privdata = devm_kzalloc(&pci_dev->dev, sizeof(*privdata), GFP_KERNEL);
	if (!privdata)
		return -ENOMEM;

	privdata->pci_dev = pci_dev;
	rc = amd_mp2_pci_init(privdata, pci_dev);
	if (rc)
		return rc;

	mutex_init(&privdata->c2p_lock);

	pm_runtime_set_autosuspend_delay(&pci_dev->dev, 1000);
	pm_runtime_use_autosuspend(&pci_dev->dev);
	pm_runtime_put_autosuspend(&pci_dev->dev);
	pm_runtime_allow(&pci_dev->dev);

	privdata->probed = true;

	pci_info(pci_dev, "MP2 device registered.\n");
	return 0;
}

static void amd_mp2_pci_remove(struct pci_dev *pci_dev)
{
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);

	pm_runtime_forbid(&pci_dev->dev);
	pm_runtime_get_noresume(&pci_dev->dev);

	pci_intx(pci_dev, 0);
	pci_clear_master(pci_dev);

	amd_mp2_clear_reg(privdata);
}

#ifdef CONFIG_PM
static int amd_mp2_pci_suspend(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
	struct amd_i2c_common *i2c_common;
	unsigned int bus_id;
	int ret = 0;

	for (bus_id = 0; bus_id < 2; bus_id++) {
		i2c_common = privdata->busses[bus_id];
		if (i2c_common)
			i2c_common->suspend(i2c_common);
	}

	ret = pci_save_state(pci_dev);
	if (ret) {
		pci_err(pci_dev, "pci_save_state failed = %d\n", ret);
		return ret;
	}

	pci_disable_device(pci_dev);
	return ret;
}

static int amd_mp2_pci_resume(struct device *dev)
{
	struct pci_dev *pci_dev = to_pci_dev(dev);
	struct amd_mp2_dev *privdata = pci_get_drvdata(pci_dev);
	struct amd_i2c_common *i2c_common;
	unsigned int bus_id;
	int ret = 0;

	pci_restore_state(pci_dev);
	ret = pci_enable_device(pci_dev);
	if (ret < 0) {
		pci_err(pci_dev, "pci_enable_device failed = %d\n", ret);
		return ret;
	}

	for (bus_id = 0; bus_id < 2; bus_id++) {
		i2c_common = privdata->busses[bus_id];
		if (i2c_common) {
			ret = i2c_common->resume(i2c_common);
			if (ret < 0)
				return ret;
		}
	}

	return ret;
}

static UNIVERSAL_DEV_PM_OPS(amd_mp2_pci_pm_ops, amd_mp2_pci_suspend,
			    amd_mp2_pci_resume, NULL);
#endif /* CONFIG_PM */

static const struct pci_device_id amd_mp2_pci_tbl[] = {
	{PCI_VDEVICE(AMD, PCI_DEVICE_ID_AMD_MP2)},
	{0}
};
MODULE_DEVICE_TABLE(pci, amd_mp2_pci_tbl);

static struct pci_driver amd_mp2_pci_driver = {
	.name		= "i2c_amd_mp2",
	.id_table	= amd_mp2_pci_tbl,
	.probe		= amd_mp2_pci_probe,
	.remove		= amd_mp2_pci_remove,
#ifdef CONFIG_PM
	.driver = {
		.pm	= &amd_mp2_pci_pm_ops,
	},
#endif
};
module_pci_driver(amd_mp2_pci_driver);

struct amd_mp2_dev *amd_mp2_find_device(void)
{
	struct device *dev;
	struct pci_dev *pci_dev;

	dev = driver_find_next_device(&amd_mp2_pci_driver.driver, NULL);
	if (!dev)
		return NULL;

	pci_dev = to_pci_dev(dev);
	return (struct amd_mp2_dev *)pci_get_drvdata(pci_dev);
}
EXPORT_SYMBOL_GPL(amd_mp2_find_device);

MODULE_DESCRIPTION("AMD(R) PCI-E MP2 I2C Controller Driver");
MODULE_AUTHOR("Shyam Sundar S K <Shyam-sundar.S-k@amd.com>");
MODULE_AUTHOR("Elie Morisse <syniurge@gmail.com>");
MODULE_LICENSE("Dual BSD/GPL");