aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/s390/cio/ccwreq.c
blob: 7a28a3029a3f9d747a9ecf59d572c7146de74a1b (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
/*
 *  Handling of internal CCW device requests.
 *
 *    Copyright IBM Corp. 2009
 *    Author(s): Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
 */

#include <linux/types.h>
#include <linux/err.h>
#include <asm/ccwdev.h>
#include <asm/cio.h>

#include "io_sch.h"
#include "cio.h"
#include "device.h"
#include "cio_debug.h"

/**
 * lpm_adjust - adjust path mask
 * @lpm: path mask to adjust
 * @mask: mask of available paths
 *
 * Shift @lpm right until @lpm and @mask have at least one bit in common or
 * until @lpm is zero. Return the resulting lpm.
 */
int lpm_adjust(int lpm, int mask)
{
	while (lpm && ((lpm & mask) == 0))
		lpm >>= 1;
	return lpm;
}

/*
 * Adjust path mask to use next path and reset retry count. Return resulting
 * path mask.
 */
static u16 ccwreq_next_path(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;

	req->retries	= req->maxretries;
	req->mask	= lpm_adjust(req->mask >>= 1, req->lpm);

	return req->mask;
}

/*
 * Clean up device state and report to callback.
 */
static void ccwreq_stop(struct ccw_device *cdev, int rc)
{
	struct ccw_request *req = &cdev->private->req;

	if (req->done)
		return;
	req->done = 1;
	ccw_device_set_timeout(cdev, 0);
	memset(&cdev->private->irb, 0, sizeof(struct irb));
	if (rc && rc != -ENODEV && req->drc)
		rc = req->drc;
	req->callback(cdev, req->data, rc);
}

/*
 * (Re-)Start the operation until retries and paths are exhausted.
 */
static void ccwreq_do(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw1 *cp = req->cp;
	int rc = -EACCES;

	while (req->mask) {
		if (req->retries-- == 0) {
			/* Retries exhausted, try next path. */
			ccwreq_next_path(cdev);
			continue;
		}
		/* Perform start function. */
		memset(&cdev->private->irb, 0, sizeof(struct irb));
		rc = cio_start(sch, cp, (u8) req->mask);
		if (rc == 0) {
			/* I/O started successfully. */
			ccw_device_set_timeout(cdev, req->timeout);
			return;
		}
		if (rc == -ENODEV) {
			/* Permanent device error. */
			break;
		}
		if (rc == -EACCES) {
			/* Permant path error. */
			ccwreq_next_path(cdev);
			continue;
		}
		/* Temporary improper status. */
		rc = cio_clear(sch);
		if (rc)
			break;
		return;
	}
	ccwreq_stop(cdev, rc);
}

/**
 * ccw_request_start - perform I/O request
 * @cdev: ccw device
 *
 * Perform the I/O request specified by cdev->req.
 */
void ccw_request_start(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;

	/* Try all paths twice to counter link flapping. */
	req->mask	= 0x8080;
	req->retries	= req->maxretries;
	req->mask	= lpm_adjust(req->mask, req->lpm);
	req->drc	= 0;
	req->done	= 0;
	req->cancel	= 0;
	if (!req->mask)
		goto out_nopath;
	ccwreq_do(cdev);
	return;

out_nopath:
	ccwreq_stop(cdev, -EACCES);
}

/**
 * ccw_request_cancel - cancel running I/O request
 * @cdev: ccw device
 *
 * Cancel the I/O request specified by cdev->req. Return non-zero if request
 * has already finished, zero otherwise.
 */
int ccw_request_cancel(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	int rc;

	if (req->done)
		return 1;
	req->cancel = 1;
	rc = cio_clear(sch);
	if (rc)
		ccwreq_stop(cdev, rc);
	return 0;
}

/*
 * Return the status of the internal I/O started on the specified ccw device.
 * Perform BASIC SENSE if required.
 */
static enum io_status ccwreq_status(struct ccw_device *cdev, struct irb *lcirb)
{
	struct irb *irb = &cdev->private->irb;
	struct cmd_scsw *scsw = &irb->scsw.cmd;

	/* Perform BASIC SENSE if needed. */
	if (ccw_device_accumulate_and_sense(cdev, lcirb))
		return IO_RUNNING;
	/* Check for halt/clear interrupt. */
	if (scsw->fctl & (SCSW_FCTL_HALT_FUNC | SCSW_FCTL_CLEAR_FUNC))
		return IO_KILLED;
	/* Check for path error. */
	if (scsw->cc == 3 || scsw->pno)
		return IO_PATH_ERROR;
	/* Handle BASIC SENSE data. */
	if (irb->esw.esw0.erw.cons) {
		CIO_TRACE_EVENT(2, "sensedata");
		CIO_HEX_EVENT(2, &cdev->private->dev_id,
			      sizeof(struct ccw_dev_id));
		CIO_HEX_EVENT(2, &cdev->private->irb.ecw, SENSE_MAX_COUNT);
		/* Check for command reject. */
		if (irb->ecw[0] & SNS0_CMD_REJECT)
			return IO_REJECTED;
		/* Assume that unexpected SENSE data implies an error. */
		return IO_STATUS_ERROR;
	}
	/* Check for channel errors. */
	if (scsw->cstat != 0)
		return IO_STATUS_ERROR;
	/* Check for device errors. */
	if (scsw->dstat & ~(DEV_STAT_CHN_END | DEV_STAT_DEV_END))
		return IO_STATUS_ERROR;
	/* Check for final state. */
	if (!(scsw->dstat & DEV_STAT_DEV_END))
		return IO_RUNNING;
	/* Check for other improper status. */
	if (scsw->cc == 1 && (scsw->stctl & SCSW_STCTL_ALERT_STATUS))
		return IO_STATUS_ERROR;
	return IO_DONE;
}

/*
 * Log ccw request status.
 */
static void ccwreq_log_status(struct ccw_device *cdev, enum io_status status)
{
	struct ccw_request *req = &cdev->private->req;
	struct {
		struct ccw_dev_id dev_id;
		u16 retries;
		u8 lpm;
		u8 status;
	}  __attribute__ ((packed)) data;
	data.dev_id	= cdev->private->dev_id;
	data.retries	= req->retries;
	data.lpm	= (u8) req->mask;
	data.status	= (u8) status;
	CIO_TRACE_EVENT(2, "reqstat");
	CIO_HEX_EVENT(2, &data, sizeof(data));
}

/**
 * ccw_request_handler - interrupt handler for I/O request procedure.
 * @cdev: ccw device
 *
 * Handle interrupt during I/O request procedure.
 */
void ccw_request_handler(struct ccw_device *cdev)
{
	struct ccw_request *req = &cdev->private->req;
	struct irb *irb = (struct irb *) __LC_IRB;
	enum io_status status;
	int rc = -EOPNOTSUPP;

	/* Check status of I/O request. */
	status = ccwreq_status(cdev, irb);
	if (req->filter)
		status = req->filter(cdev, req->data, irb, status);
	if (status != IO_RUNNING)
		ccw_device_set_timeout(cdev, 0);
	if (status != IO_DONE && status != IO_RUNNING)
		ccwreq_log_status(cdev, status);
	switch (status) {
	case IO_DONE:
		break;
	case IO_RUNNING:
		return;
	case IO_REJECTED:
		goto err;
	case IO_PATH_ERROR:
		goto out_next_path;
	case IO_STATUS_ERROR:
		goto out_restart;
	case IO_KILLED:
		/* Check if request was cancelled on purpose. */
		if (req->cancel) {
			rc = -EIO;
			goto err;
		}
		goto out_restart;
	}
	/* Check back with request initiator. */
	if (!req->check)
		goto out;
	switch (req->check(cdev, req->data)) {
	case 0:
		break;
	case -EAGAIN:
		goto out_restart;
	case -EACCES:
		goto out_next_path;
	default:
		goto err;
	}
out:
	ccwreq_stop(cdev, 0);
	return;

out_next_path:
	/* Try next path and restart I/O. */
	if (!ccwreq_next_path(cdev)) {
		rc = -EACCES;
		goto err;
	}
out_restart:
	/* Restart. */
	ccwreq_do(cdev);
	return;
err:
	ccwreq_stop(cdev, rc);
}


/**
 * ccw_request_timeout - timeout handler for I/O request procedure
 * @cdev: ccw device
 *
 * Handle timeout during I/O request procedure.
 */
void ccw_request_timeout(struct ccw_device *cdev)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct ccw_request *req = &cdev->private->req;
	int rc;

	if (!ccwreq_next_path(cdev)) {
		/* set the final return code for this request */
		req->drc = -ETIME;
	}
	rc = cio_clear(sch);
	if (rc)
		goto err;
	return;

err:
	ccwreq_stop(cdev, rc);
}

/**
 * ccw_request_notoper - notoper handler for I/O request procedure
 * @cdev: ccw device
 *
 * Handle timeout during I/O request procedure.
 */
void ccw_request_notoper(struct ccw_device *cdev)
{
	ccwreq_stop(cdev, -ENODEV);
}