summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/s390/cio/qdio_thinint.c
blob: 5d06253c2a7a385df2a2d951c49992a006d21600 (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
/*
 * Copyright IBM Corp. 2000, 2009
 * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
 *	      Cornelia Huck <cornelia.huck@de.ibm.com>
 *	      Jan Glauber <jang@linux.vnet.ibm.com>
 */
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/kernel_stat.h>
#include <linux/atomic.h>
#include <asm/debug.h>
#include <asm/qdio.h>
#include <asm/airq.h>
#include <asm/isc.h>

#include "cio.h"
#include "ioasm.h"
#include "qdio.h"
#include "qdio_debug.h"

/*
 * Restriction: only 63 iqdio subchannels would have its own indicator,
 * after that, subsequent subchannels share one indicator
 */
#define TIQDIO_NR_NONSHARED_IND		63
#define TIQDIO_NR_INDICATORS		(TIQDIO_NR_NONSHARED_IND + 1)
#define TIQDIO_SHARED_IND		63

/* device state change indicators */
struct indicator_t {
	u32 ind;	/* u32 because of compare-and-swap performance */
	atomic_t count; /* use count, 0 or 1 for non-shared indicators */
};

/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
static DEFINE_MUTEX(tiq_list_lock);

/* Adapter interrupt definitions */
static void tiqdio_thinint_handler(struct airq_struct *airq);

static struct airq_struct tiqdio_airq = {
	.handler = tiqdio_thinint_handler,
	.isc = QDIO_AIRQ_ISC,
};

static struct indicator_t *q_indicators;

u64 last_ai_time;

/* returns addr for the device state change indicator */
static u32 *get_indicator(void)
{
	int i;

	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
		if (!atomic_read(&q_indicators[i].count)) {
			atomic_set(&q_indicators[i].count, 1);
			return &q_indicators[i].ind;
		}

	/* use the shared indicator */
	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
	return &q_indicators[TIQDIO_SHARED_IND].ind;
}

static void put_indicator(u32 *addr)
{
	int i;

	if (!addr)
		return;
	i = ((unsigned long)addr - (unsigned long)q_indicators) /
		sizeof(struct indicator_t);
	atomic_dec(&q_indicators[i].count);
}

void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
{
	mutex_lock(&tiq_list_lock);
	list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
	mutex_unlock(&tiq_list_lock);
	xchg(irq_ptr->dsci, 1 << 7);
}

void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
{
	struct qdio_q *q;

	q = irq_ptr->input_qs[0];
	/* if establish triggered an error */
	if (!q || !q->entry.prev || !q->entry.next)
		return;

	mutex_lock(&tiq_list_lock);
	list_del_rcu(&q->entry);
	mutex_unlock(&tiq_list_lock);
	synchronize_rcu();
}

static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
{
	return irq_ptr->nr_input_qs > 1;
}

static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
{
	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}

static inline int shared_ind(struct qdio_irq *irq_ptr)
{
	return references_shared_dsci(irq_ptr) ||
		has_multiple_inq_on_dsci(irq_ptr);
}

void clear_nonshared_ind(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;
	if (shared_ind(irq_ptr))
		return;
	xchg(irq_ptr->dsci, 0);
}

int test_nonshared_ind(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return 0;
	if (shared_ind(irq_ptr))
		return 0;
	if (*irq_ptr->dsci)
		return 1;
	else
		return 0;
}

static inline u32 clear_shared_ind(void)
{
	if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
		return 0;
	return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
}

static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
{
	struct qdio_q *q;
	int i;

	for_each_input_queue(irq, q, i) {
		if (!references_shared_dsci(irq) &&
		    has_multiple_inq_on_dsci(irq))
			xchg(q->irq_ptr->dsci, 0);

		if (q->u.in.queue_start_poll) {
			/* skip if polling is enabled or already in work */
			if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
					     &q->u.in.queue_irq_state)) {
				qperf_inc(q, int_discarded);
				continue;
			}

			/* avoid dsci clear here, done after processing */
			q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
						 q->irq_ptr->int_parm);
		} else {
			if (!shared_ind(q->irq_ptr))
				xchg(q->irq_ptr->dsci, 0);

			/*
			 * Call inbound processing but not directly
			 * since that could starve other thinint queues.
			 */
			tasklet_schedule(&q->tasklet);
		}
	}
}

/**
 * tiqdio_thinint_handler - thin interrupt handler for qdio
 * @alsi: pointer to adapter local summary indicator
 * @data: NULL
 */
static void tiqdio_thinint_handler(struct airq_struct *airq)
{
	u32 si_used = clear_shared_ind();
	struct qdio_q *q;

	last_ai_time = S390_lowcore.int_clock;
	inc_irq_stat(IRQIO_QAI);

	/* protect tiq_list entries, only changed in activate or shutdown */
	rcu_read_lock();

	/* check for work on all inbound thinint queues */
	list_for_each_entry_rcu(q, &tiq_list, entry) {
		struct qdio_irq *irq;

		/* only process queues from changed sets */
		irq = q->irq_ptr;
		if (unlikely(references_shared_dsci(irq))) {
			if (!si_used)
				continue;
		} else if (!*irq->dsci)
			continue;

		tiqdio_call_inq_handlers(irq);

		qperf_inc(q, adapter_int);
	}
	rcu_read_unlock();
}

static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
{
	struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page;
	u64 summary_indicator_addr, subchannel_indicator_addr;
	int rc;

	if (reset) {
		summary_indicator_addr = 0;
		subchannel_indicator_addr = 0;
	} else {
		summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr);
		subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci);
	}

	rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr,
		       subchannel_indicator_addr);
	if (rc) {
		DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
			  scssc->response.code);
		goto out;
	}

	DBF_EVENT("setscind");
	DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr));
	DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr));
out:
	return rc;
}

/* allocate non-shared indicators and shared indicator */
int __init tiqdio_allocate_memory(void)
{
	q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
			     GFP_KERNEL);
	if (!q_indicators)
		return -ENOMEM;
	return 0;
}

void tiqdio_free_memory(void)
{
	kfree(q_indicators);
}

int __init tiqdio_register_thinints(void)
{
	int rc;

	rc = register_adapter_interrupt(&tiqdio_airq);
	if (rc) {
		DBF_EVENT("RTI:%x", rc);
		return rc;
	}
	return 0;
}

int qdio_establish_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return 0;
	return set_subchannel_ind(irq_ptr, 0);
}

void qdio_setup_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;
	irq_ptr->dsci = get_indicator();
	DBF_HEX(&irq_ptr->dsci, sizeof(void *));
}

void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;

	/* reset adapter interrupt indicators */
	set_subchannel_ind(irq_ptr, 1);
	put_indicator(irq_ptr->dsci);
}

void __exit tiqdio_unregister_thinints(void)
{
	WARN_ON(!list_empty(&tiq_list));
	unregister_adapter_interrupt(&tiqdio_airq);
}