summaryrefslogtreecommitdiffstats
path: root/drivers/s390/cio/qdio_thinint.c
blob: c655d011a78dac28ef5768a2aa0317d761b4e06a (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
/*
 * linux/drivers/s390/cio/thinint_qdio.c
 *
 * thin interrupt support for qdio
 *
 * Copyright 2000-2008 IBM Corp.
 * 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 <asm/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"
#include "qdio_perf.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

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

/* adapter local summary indicator */
static unsigned char *tiqdio_alsi;

/* 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 */
};
static struct indicator_t *q_indicators;

static void tiqdio_tasklet_fn(unsigned long data);
static DECLARE_TASKLET(tiqdio_tasklet, tiqdio_tasklet_fn, 0);

static int css_qdio_omit_svs;

static inline unsigned long do_clear_global_summary(void)
{
	register unsigned long __fn asm("1") = 3;
	register unsigned long __tmp asm("2");
	register unsigned long __time asm("3");

	asm volatile(
		"	.insn	rre,0xb2650000,2,0"
		: "+d" (__fn), "=d" (__tmp), "=d" (__time));
	return __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)
{
	struct qdio_q *q;
	int i;

	/* No TDD facility? If we must use SIGA-s we can also omit SVS. */
	if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
		css_qdio_omit_svs = 1;

	mutex_lock(&tiq_list_lock);
	for_each_input_queue(irq_ptr, q, i)
		list_add_rcu(&q->entry, &tiq_list);
	mutex_unlock(&tiq_list_lock);
	xchg(irq_ptr->dsci, 1);
}

/*
 * we cannot stop the tiqdio tasklet here since it is for all
 * thinint qdio devices and it must run as long as there is a
 * thinint device left
 */
void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
{
	struct qdio_q *q;
	int i;

	for (i = 0; i < irq_ptr->nr_input_qs; i++) {
		q = irq_ptr->input_qs[i];
		/* if establish triggered an error */
		if (!q || !q->entry.prev || !q->entry.next)
			continue;

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

static inline int tiqdio_inbound_q_done(struct qdio_q *q)
{
	unsigned char state = 0;

	if (!atomic_read(&q->nr_buf_used))
		return 1;

	qdio_siga_sync_q(q);
	get_buf_state(q, q->first_to_check, &state, 0);

	if (state == SLSB_P_INPUT_PRIMED)
		/* more work coming */
		return 0;
	return 1;
}

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

static void __tiqdio_inbound_processing(struct qdio_q *q)
{
	qdio_perf_stat_inc(&perf_stats.thinint_inbound);
	qdio_sync_after_thinint(q);

	/*
	 * Maybe we have work on our outbound queues... at least
	 * we have to check the PCI capable queues.
	 */
	qdio_check_outbound_after_thinint(q);

	if (!qdio_inbound_q_moved(q))
		return;

	qdio_kick_handler(q);

	if (!tiqdio_inbound_q_done(q)) {
		qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
		if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
			tasklet_schedule(&q->tasklet);
	}

	qdio_stop_polling(q);
	/*
	 * We need to check again to not lose initiative after
	 * resetting the ACK state.
	 */
	if (!tiqdio_inbound_q_done(q)) {
		qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
		if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
			tasklet_schedule(&q->tasklet);
	}
}

void tiqdio_inbound_processing(unsigned long data)
{
	struct qdio_q *q = (struct qdio_q *)data;

	__tiqdio_inbound_processing(q);
}

/* check for work on all inbound thinint queues */
static void tiqdio_tasklet_fn(unsigned long data)
{
	struct qdio_q *q;

	qdio_perf_stat_inc(&perf_stats.tasklet_thinint);
again:

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

	list_for_each_entry_rcu(q, &tiq_list, entry)
		/* only process queues from changed sets */
		if (*q->irq_ptr->dsci) {

			/* only clear it if the indicator is non-shared */
			if (!shared_ind(q->irq_ptr))
				xchg(q->irq_ptr->dsci, 0);
			/*
			 * don't call inbound processing directly since
			 * that could starve other thinint queues
			 */
			tasklet_schedule(&q->tasklet);
		}

	rcu_read_unlock();

	/*
	 * if we used the shared indicator clear it now after all queues
	 * were processed
	 */
	if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
		xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);

		/* prevent racing */
		if (*tiqdio_alsi)
			xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
	}

	/* check for more work */
	if (*tiqdio_alsi) {
		xchg(tiqdio_alsi, 0);
		qdio_perf_stat_inc(&perf_stats.tasklet_thinint_loop);
		goto again;
	}
}

/**
 * tiqdio_thinint_handler - thin interrupt handler for qdio
 * @ind: pointer to adapter local summary indicator
 * @drv_data: NULL
 */
static void tiqdio_thinint_handler(void *ind, void *drv_data)
{
	qdio_perf_stat_inc(&perf_stats.thin_int);

	/*
	 * SVS only when needed: issue SVS to benefit from iqdio interrupt
	 * avoidance (SVS clears adapter interrupt suppression overwrite)
	 */
	if (!css_qdio_omit_svs)
		do_clear_global_summary();

	/*
	 * reset local summary indicator (tiqdio_alsi) to stop adapter
	 * interrupts for now, the tasklet will clean all dsci's
	 */
	xchg((u8 *)ind, 0);
	tasklet_hi_schedule(&tiqdio_tasklet);
}

static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
{
	struct scssc_area *scssc_area;
	int rc;

	scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
	memset(scssc_area, 0, PAGE_SIZE);

	if (reset) {
		scssc_area->summary_indicator_addr = 0;
		scssc_area->subchannel_indicator_addr = 0;
	} else {
		scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
		scssc_area->subchannel_indicator_addr =
			virt_to_phys(irq_ptr->dsci);
	}

	scssc_area->request = (struct chsc_header) {
		.length = 0x0fe0,
		.code	= 0x0021,
	};
	scssc_area->operation_code = 0;
	scssc_area->ks = PAGE_DEFAULT_KEY;
	scssc_area->kc = PAGE_DEFAULT_KEY;
	scssc_area->isc = QDIO_AIRQ_ISC;
	scssc_area->schid = irq_ptr->schid;

	/* enable the time delay disablement facility */
	if (css_general_characteristics.aif_tdd)
		scssc_area->word_with_d_bit = 0x10000000;

	rc = chsc(scssc_area);
	if (rc)
		return -EIO;

	rc = chsc_error_from_response(scssc_area->response.code);
	if (rc) {
		DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
			  scssc_area->response.code);
		DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
		return rc;
	}

	DBF_EVENT("setscind");
	DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
	DBF_HEX(&scssc_area->subchannel_indicator_addr,	sizeof(unsigned long));
	return 0;
}

/* 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)
{
	isc_register(QDIO_AIRQ_ISC);
	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
						      NULL, QDIO_AIRQ_ISC);
	if (IS_ERR(tiqdio_alsi)) {
		DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
		tiqdio_alsi = NULL;
		isc_unregister(QDIO_AIRQ_ISC);
		return -ENOMEM;
	}
	return 0;
}

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

	/* Check for aif time delay disablement. If installed,
	 * omit SVS even under LPAR
	 */
	if (css_general_characteristics.aif_tdd)
		css_qdio_omit_svs = 1;
	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 */
	put_indicator(irq_ptr->dsci);
	set_subchannel_ind(irq_ptr, 1);
}

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

	if (tiqdio_alsi) {
		s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
		isc_unregister(QDIO_AIRQ_ISC);
	}
	tasklet_kill(&tiqdio_tasklet);
}