summaryrefslogtreecommitdiffstats
path: root/drivers/char/ipmi/kcs_bmc.c
blob: ed4dc3b1843e3a06995750deda672b5bb830444a (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2015-2018, Intel Corporation.
 */

#define pr_fmt(fmt) "kcs-bmc: " fmt

#include <linux/errno.h>
#include <linux/io.h>
#include <linux/ipmi_bmc.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>

#include "kcs_bmc.h"

#define DEVICE_NAME "ipmi-kcs"

#define KCS_MSG_BUFSIZ    1000

#define KCS_ZERO_DATA     0


/* IPMI 2.0 - Table 9-1, KCS Interface Status Register Bits */
#define KCS_STATUS_STATE(state) (state << 6)
#define KCS_STATUS_STATE_MASK   GENMASK(7, 6)
#define KCS_STATUS_CMD_DAT      BIT(3)
#define KCS_STATUS_SMS_ATN      BIT(2)
#define KCS_STATUS_IBF          BIT(1)
#define KCS_STATUS_OBF          BIT(0)

/* IPMI 2.0 - Table 9-2, KCS Interface State Bits */
enum kcs_states {
	IDLE_STATE  = 0,
	READ_STATE  = 1,
	WRITE_STATE = 2,
	ERROR_STATE = 3,
};

/* IPMI 2.0 - Table 9-3, KCS Interface Control Codes */
#define KCS_CMD_GET_STATUS_ABORT  0x60
#define KCS_CMD_WRITE_START       0x61
#define KCS_CMD_WRITE_END         0x62
#define KCS_CMD_READ_BYTE         0x68

static inline u8 read_data(struct kcs_bmc *kcs_bmc)
{
	return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.idr);
}

static inline void write_data(struct kcs_bmc *kcs_bmc, u8 data)
{
	kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.odr, data);
}

static inline u8 read_status(struct kcs_bmc *kcs_bmc)
{
	return kcs_bmc->io_inputb(kcs_bmc, kcs_bmc->ioreg.str);
}

static inline void write_status(struct kcs_bmc *kcs_bmc, u8 data)
{
	kcs_bmc->io_outputb(kcs_bmc, kcs_bmc->ioreg.str, data);
}

static void update_status_bits(struct kcs_bmc *kcs_bmc, u8 mask, u8 val)
{
	u8 tmp = read_status(kcs_bmc);

	tmp &= ~mask;
	tmp |= val & mask;

	write_status(kcs_bmc, tmp);
}

static inline void set_state(struct kcs_bmc *kcs_bmc, u8 state)
{
	update_status_bits(kcs_bmc, KCS_STATUS_STATE_MASK,
					KCS_STATUS_STATE(state));
}

static void kcs_force_abort(struct kcs_bmc *kcs_bmc)
{
	set_state(kcs_bmc, ERROR_STATE);
	read_data(kcs_bmc);
	write_data(kcs_bmc, KCS_ZERO_DATA);

	kcs_bmc->phase = KCS_PHASE_ERROR;
	kcs_bmc->data_in_avail = false;
	kcs_bmc->data_in_idx = 0;
}

static void kcs_bmc_handle_data(struct kcs_bmc *kcs_bmc)
{
	u8 data;

	switch (kcs_bmc->phase) {
	case KCS_PHASE_WRITE_START:
		kcs_bmc->phase = KCS_PHASE_WRITE_DATA;
		/* fall through */

	case KCS_PHASE_WRITE_DATA:
		if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) {
			set_state(kcs_bmc, WRITE_STATE);
			write_data(kcs_bmc, KCS_ZERO_DATA);
			kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
						read_data(kcs_bmc);
		} else {
			kcs_force_abort(kcs_bmc);
			kcs_bmc->error = KCS_LENGTH_ERROR;
		}
		break;

	case KCS_PHASE_WRITE_END_CMD:
		if (kcs_bmc->data_in_idx < KCS_MSG_BUFSIZ) {
			set_state(kcs_bmc, READ_STATE);
			kcs_bmc->data_in[kcs_bmc->data_in_idx++] =
						read_data(kcs_bmc);
			kcs_bmc->phase = KCS_PHASE_WRITE_DONE;
			kcs_bmc->data_in_avail = true;
			wake_up_interruptible(&kcs_bmc->queue);
		} else {
			kcs_force_abort(kcs_bmc);
			kcs_bmc->error = KCS_LENGTH_ERROR;
		}
		break;

	case KCS_PHASE_READ:
		if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len)
			set_state(kcs_bmc, IDLE_STATE);

		data = read_data(kcs_bmc);
		if (data != KCS_CMD_READ_BYTE) {
			set_state(kcs_bmc, ERROR_STATE);
			write_data(kcs_bmc, KCS_ZERO_DATA);
			break;
		}

		if (kcs_bmc->data_out_idx == kcs_bmc->data_out_len) {
			write_data(kcs_bmc, KCS_ZERO_DATA);
			kcs_bmc->phase = KCS_PHASE_IDLE;
			break;
		}

		write_data(kcs_bmc,
			kcs_bmc->data_out[kcs_bmc->data_out_idx++]);
		break;

	case KCS_PHASE_ABORT_ERROR1:
		set_state(kcs_bmc, READ_STATE);
		read_data(kcs_bmc);
		write_data(kcs_bmc, kcs_bmc->error);
		kcs_bmc->phase = KCS_PHASE_ABORT_ERROR2;
		break;

	case KCS_PHASE_ABORT_ERROR2:
		set_state(kcs_bmc, IDLE_STATE);
		read_data(kcs_bmc);
		write_data(kcs_bmc, KCS_ZERO_DATA);
		kcs_bmc->phase = KCS_PHASE_IDLE;
		break;

	default:
		kcs_force_abort(kcs_bmc);
		break;
	}
}

static void kcs_bmc_handle_cmd(struct kcs_bmc *kcs_bmc)
{
	u8 cmd;

	set_state(kcs_bmc, WRITE_STATE);
	write_data(kcs_bmc, KCS_ZERO_DATA);

	cmd = read_data(kcs_bmc);
	switch (cmd) {
	case KCS_CMD_WRITE_START:
		kcs_bmc->phase = KCS_PHASE_WRITE_START;
		kcs_bmc->error = KCS_NO_ERROR;
		kcs_bmc->data_in_avail = false;
		kcs_bmc->data_in_idx = 0;
		break;

	case KCS_CMD_WRITE_END:
		if (kcs_bmc->phase != KCS_PHASE_WRITE_DATA) {
			kcs_force_abort(kcs_bmc);
			break;
		}

		kcs_bmc->phase = KCS_PHASE_WRITE_END_CMD;
		break;

	case KCS_CMD_GET_STATUS_ABORT:
		if (kcs_bmc->error == KCS_NO_ERROR)
			kcs_bmc->error = KCS_ABORTED_BY_COMMAND;

		kcs_bmc->phase = KCS_PHASE_ABORT_ERROR1;
		kcs_bmc->data_in_avail = false;
		kcs_bmc->data_in_idx = 0;
		break;

	default:
		kcs_force_abort(kcs_bmc);
		kcs_bmc->error = KCS_ILLEGAL_CONTROL_CODE;
		break;
	}
}

int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc)
{
	unsigned long flags;
	int ret = -ENODATA;
	u8 status;

	spin_lock_irqsave(&kcs_bmc->lock, flags);

	status = read_status(kcs_bmc);
	if (status & KCS_STATUS_IBF) {
		if (!kcs_bmc->running)
			kcs_force_abort(kcs_bmc);
		else if (status & KCS_STATUS_CMD_DAT)
			kcs_bmc_handle_cmd(kcs_bmc);
		else
			kcs_bmc_handle_data(kcs_bmc);

		ret = 0;
	}

	spin_unlock_irqrestore(&kcs_bmc->lock, flags);

	return ret;
}
EXPORT_SYMBOL(kcs_bmc_handle_event);

static inline struct kcs_bmc *to_kcs_bmc(struct file *filp)
{
	return container_of(filp->private_data, struct kcs_bmc, miscdev);
}

static int kcs_bmc_open(struct inode *inode, struct file *filp)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);
	int ret = 0;

	spin_lock_irq(&kcs_bmc->lock);
	if (!kcs_bmc->running)
		kcs_bmc->running = 1;
	else
		ret = -EBUSY;
	spin_unlock_irq(&kcs_bmc->lock);

	return ret;
}

static __poll_t kcs_bmc_poll(struct file *filp, poll_table *wait)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);
	__poll_t mask = 0;

	poll_wait(filp, &kcs_bmc->queue, wait);

	spin_lock_irq(&kcs_bmc->lock);
	if (kcs_bmc->data_in_avail)
		mask |= EPOLLIN;
	spin_unlock_irq(&kcs_bmc->lock);

	return mask;
}

static ssize_t kcs_bmc_read(struct file *filp, char __user *buf,
			    size_t count, loff_t *ppos)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);
	bool data_avail;
	size_t data_len;
	ssize_t ret;

	if (!(filp->f_flags & O_NONBLOCK))
		wait_event_interruptible(kcs_bmc->queue,
					 kcs_bmc->data_in_avail);

	mutex_lock(&kcs_bmc->mutex);

	spin_lock_irq(&kcs_bmc->lock);
	data_avail = kcs_bmc->data_in_avail;
	if (data_avail) {
		data_len = kcs_bmc->data_in_idx;
		memcpy(kcs_bmc->kbuffer, kcs_bmc->data_in, data_len);
	}
	spin_unlock_irq(&kcs_bmc->lock);

	if (!data_avail) {
		ret = -EAGAIN;
		goto out_unlock;
	}

	if (count < data_len) {
		pr_err("channel=%u with too large data : %zu\n",
			kcs_bmc->channel, data_len);

		spin_lock_irq(&kcs_bmc->lock);
		kcs_force_abort(kcs_bmc);
		spin_unlock_irq(&kcs_bmc->lock);

		ret = -EOVERFLOW;
		goto out_unlock;
	}

	if (copy_to_user(buf, kcs_bmc->kbuffer, data_len)) {
		ret = -EFAULT;
		goto out_unlock;
	}

	ret = data_len;

	spin_lock_irq(&kcs_bmc->lock);
	if (kcs_bmc->phase == KCS_PHASE_WRITE_DONE) {
		kcs_bmc->phase = KCS_PHASE_WAIT_READ;
		kcs_bmc->data_in_avail = false;
		kcs_bmc->data_in_idx = 0;
	} else {
		ret = -EAGAIN;
	}
	spin_unlock_irq(&kcs_bmc->lock);

out_unlock:
	mutex_unlock(&kcs_bmc->mutex);

	return ret;
}

static ssize_t kcs_bmc_write(struct file *filp, const char __user *buf,
			     size_t count, loff_t *ppos)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);
	ssize_t ret;

	/* a minimum response size '3' : netfn + cmd + ccode */
	if (count < 3 || count > KCS_MSG_BUFSIZ)
		return -EINVAL;

	mutex_lock(&kcs_bmc->mutex);

	if (copy_from_user(kcs_bmc->kbuffer, buf, count)) {
		ret = -EFAULT;
		goto out_unlock;
	}

	spin_lock_irq(&kcs_bmc->lock);
	if (kcs_bmc->phase == KCS_PHASE_WAIT_READ) {
		kcs_bmc->phase = KCS_PHASE_READ;
		kcs_bmc->data_out_idx = 1;
		kcs_bmc->data_out_len = count;
		memcpy(kcs_bmc->data_out, kcs_bmc->kbuffer, count);
		write_data(kcs_bmc, kcs_bmc->data_out[0]);
		ret = count;
	} else {
		ret = -EINVAL;
	}
	spin_unlock_irq(&kcs_bmc->lock);

out_unlock:
	mutex_unlock(&kcs_bmc->mutex);

	return ret;
}

static long kcs_bmc_ioctl(struct file *filp, unsigned int cmd,
			  unsigned long arg)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);
	long ret = 0;

	spin_lock_irq(&kcs_bmc->lock);

	switch (cmd) {
	case IPMI_BMC_IOCTL_SET_SMS_ATN:
		update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN,
				   KCS_STATUS_SMS_ATN);
		break;

	case IPMI_BMC_IOCTL_CLEAR_SMS_ATN:
		update_status_bits(kcs_bmc, KCS_STATUS_SMS_ATN,
				   0);
		break;

	case IPMI_BMC_IOCTL_FORCE_ABORT:
		kcs_force_abort(kcs_bmc);
		break;

	default:
		ret = -EINVAL;
		break;
	}

	spin_unlock_irq(&kcs_bmc->lock);

	return ret;
}

static int kcs_bmc_release(struct inode *inode, struct file *filp)
{
	struct kcs_bmc *kcs_bmc = to_kcs_bmc(filp);

	spin_lock_irq(&kcs_bmc->lock);
	kcs_bmc->running = 0;
	kcs_force_abort(kcs_bmc);
	spin_unlock_irq(&kcs_bmc->lock);

	return 0;
}

static const struct file_operations kcs_bmc_fops = {
	.owner          = THIS_MODULE,
	.open           = kcs_bmc_open,
	.read           = kcs_bmc_read,
	.write          = kcs_bmc_write,
	.release        = kcs_bmc_release,
	.poll           = kcs_bmc_poll,
	.unlocked_ioctl = kcs_bmc_ioctl,
};

struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 channel)
{
	struct kcs_bmc *kcs_bmc;

	kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc) + sizeof_priv, GFP_KERNEL);
	if (!kcs_bmc)
		return NULL;

	spin_lock_init(&kcs_bmc->lock);
	kcs_bmc->channel = channel;

	mutex_init(&kcs_bmc->mutex);
	init_waitqueue_head(&kcs_bmc->queue);

	kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
	kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
	kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);

	kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
	kcs_bmc->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s%u",
					       DEVICE_NAME, channel);
	if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer ||
	    !kcs_bmc->miscdev.name)
		return NULL;
	kcs_bmc->miscdev.fops = &kcs_bmc_fops;

	return kcs_bmc;
}
EXPORT_SYMBOL(kcs_bmc_alloc);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Haiyue Wang <haiyue.wang@linux.intel.com>");
MODULE_DESCRIPTION("KCS BMC to handle the IPMI request from system software");