xref: /linux/drivers/s390/cio/qdio_thinint.c (revision f2ee442115c9b6219083c019939a9cc0c9abb2f8) 
1 /*
2  * linux/drivers/s390/cio/thinint_qdio.c
3  *
4  * Copyright 2000,2009 IBM Corp.
5  * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
6  *	      Cornelia Huck <cornelia.huck@de.ibm.com>
7  *	      Jan Glauber <jang@linux.vnet.ibm.com>
8  */
9 #include <linux/io.h>
10 #include <linux/slab.h>
11 #include <linux/kernel_stat.h>
12 #include <linux/atomic.h>
13 #include <asm/debug.h>
14 #include <asm/qdio.h>
15 #include <asm/airq.h>
16 #include <asm/isc.h>
17 
18 #include "cio.h"
19 #include "ioasm.h"
20 #include "qdio.h"
21 #include "qdio_debug.h"
22 
23 /*
24  * Restriction: only 63 iqdio subchannels would have its own indicator,
25  * after that, subsequent subchannels share one indicator
26  */
27 #define TIQDIO_NR_NONSHARED_IND		63
28 #define TIQDIO_NR_INDICATORS		(TIQDIO_NR_NONSHARED_IND + 1)
29 #define TIQDIO_SHARED_IND		63
30 
31 /* device state change indicators */
32 struct indicator_t {
33 	u32 ind;	/* u32 because of compare-and-swap performance */
34 	atomic_t count; /* use count, 0 or 1 for non-shared indicators */
35 };
36 
37 /* list of thin interrupt input queues */
38 static LIST_HEAD(tiq_list);
39 static DEFINE_MUTEX(tiq_list_lock);
40 
41 /* adapter local summary indicator */
42 static u8 *tiqdio_alsi;
43 
44 static struct indicator_t *q_indicators;
45 
46 u64 last_ai_time;
47 
48 /* returns addr for the device state change indicator */
49 static u32 *get_indicator(void)
50 {
51 	int i;
52 
53 	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
54 		if (!atomic_read(&q_indicators[i].count)) {
55 			atomic_set(&q_indicators[i].count, 1);
56 			return &q_indicators[i].ind;
57 		}
58 
59 	/* use the shared indicator */
60 	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
61 	return &q_indicators[TIQDIO_SHARED_IND].ind;
62 }
63 
64 static void put_indicator(u32 *addr)
65 {
66 	int i;
67 
68 	if (!addr)
69 		return;
70 	i = ((unsigned long)addr - (unsigned long)q_indicators) /
71 		sizeof(struct indicator_t);
72 	atomic_dec(&q_indicators[i].count);
73 }
74 
75 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
76 {
77 	mutex_lock(&tiq_list_lock);
78 	BUG_ON(irq_ptr->nr_input_qs < 1);
79 	list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
80 	mutex_unlock(&tiq_list_lock);
81 	xchg(irq_ptr->dsci, 1 << 7);
82 }
83 
84 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
85 {
86 	struct qdio_q *q;
87 
88 	BUG_ON(irq_ptr->nr_input_qs < 1);
89 	q = irq_ptr->input_qs[0];
90 	/* if establish triggered an error */
91 	if (!q || !q->entry.prev || !q->entry.next)
92 		return;
93 
94 	mutex_lock(&tiq_list_lock);
95 	list_del_rcu(&q->entry);
96 	mutex_unlock(&tiq_list_lock);
97 	synchronize_rcu();
98 }
99 
100 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
101 {
102 	return irq_ptr->nr_input_qs > 1;
103 }
104 
105 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
106 {
107 	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
108 }
109 
110 static inline int shared_ind(struct qdio_irq *irq_ptr)
111 {
112 	return references_shared_dsci(irq_ptr) ||
113 		has_multiple_inq_on_dsci(irq_ptr);
114 }
115 
116 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
117 {
118 	if (!is_thinint_irq(irq_ptr))
119 		return;
120 	if (shared_ind(irq_ptr))
121 		return;
122 	xchg(irq_ptr->dsci, 0);
123 }
124 
125 int test_nonshared_ind(struct qdio_irq *irq_ptr)
126 {
127 	if (!is_thinint_irq(irq_ptr))
128 		return 0;
129 	if (shared_ind(irq_ptr))
130 		return 0;
131 	if (*irq_ptr->dsci)
132 		return 1;
133 	else
134 		return 0;
135 }
136 
137 static inline u32 clear_shared_ind(void)
138 {
139 	if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
140 		return 0;
141 	return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
142 }
143 
144 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
145 {
146 	struct qdio_q *q;
147 	int i;
148 
149 	for_each_input_queue(irq, q, i) {
150 		if (!references_shared_dsci(irq) &&
151 		    has_multiple_inq_on_dsci(irq))
152 			xchg(q->irq_ptr->dsci, 0);
153 
154 		if (q->u.in.queue_start_poll) {
155 			/* skip if polling is enabled or already in work */
156 			if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
157 					     &q->u.in.queue_irq_state)) {
158 				qperf_inc(q, int_discarded);
159 				continue;
160 			}
161 
162 			/* avoid dsci clear here, done after processing */
163 			q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
164 						 q->irq_ptr->int_parm);
165 		} else {
166 			if (!shared_ind(q->irq_ptr))
167 				xchg(q->irq_ptr->dsci, 0);
168 
169 			/*
170 			 * Call inbound processing but not directly
171 			 * since that could starve other thinint queues.
172 			 */
173 			tasklet_schedule(&q->tasklet);
174 		}
175 	}
176 }
177 
178 /**
179  * tiqdio_thinint_handler - thin interrupt handler for qdio
180  * @alsi: pointer to adapter local summary indicator
181  * @data: NULL
182  */
183 static void tiqdio_thinint_handler(void *alsi, void *data)
184 {
185 	u32 si_used = clear_shared_ind();
186 	struct qdio_q *q;
187 
188 	last_ai_time = S390_lowcore.int_clock;
189 	kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
190 
191 	/* protect tiq_list entries, only changed in activate or shutdown */
192 	rcu_read_lock();
193 
194 	/* check for work on all inbound thinint queues */
195 	list_for_each_entry_rcu(q, &tiq_list, entry) {
196 		struct qdio_irq *irq;
197 
198 		/* only process queues from changed sets */
199 		irq = q->irq_ptr;
200 		if (unlikely(references_shared_dsci(irq))) {
201 			if (!si_used)
202 				continue;
203 		} else if (!*irq->dsci)
204 			continue;
205 
206 		tiqdio_call_inq_handlers(irq);
207 
208 		qperf_inc(q, adapter_int);
209 	}
210 	rcu_read_unlock();
211 }
212 
213 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
214 {
215 	struct scssc_area *scssc_area;
216 	int rc;
217 
218 	scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
219 	memset(scssc_area, 0, PAGE_SIZE);
220 
221 	if (reset) {
222 		scssc_area->summary_indicator_addr = 0;
223 		scssc_area->subchannel_indicator_addr = 0;
224 	} else {
225 		scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
226 		scssc_area->subchannel_indicator_addr =
227 			virt_to_phys(irq_ptr->dsci);
228 	}
229 
230 	scssc_area->request = (struct chsc_header) {
231 		.length = 0x0fe0,
232 		.code	= 0x0021,
233 	};
234 	scssc_area->operation_code = 0;
235 	scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
236 	scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
237 	scssc_area->isc = QDIO_AIRQ_ISC;
238 	scssc_area->schid = irq_ptr->schid;
239 
240 	/* enable the time delay disablement facility */
241 	if (css_general_characteristics.aif_tdd)
242 		scssc_area->word_with_d_bit = 0x10000000;
243 
244 	rc = chsc(scssc_area);
245 	if (rc)
246 		return -EIO;
247 
248 	rc = chsc_error_from_response(scssc_area->response.code);
249 	if (rc) {
250 		DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
251 			  scssc_area->response.code);
252 		DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
253 		return rc;
254 	}
255 
256 	DBF_EVENT("setscind");
257 	DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
258 	DBF_HEX(&scssc_area->subchannel_indicator_addr,	sizeof(unsigned long));
259 	return 0;
260 }
261 
262 /* allocate non-shared indicators and shared indicator */
263 int __init tiqdio_allocate_memory(void)
264 {
265 	q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
266 			     GFP_KERNEL);
267 	if (!q_indicators)
268 		return -ENOMEM;
269 	return 0;
270 }
271 
272 void tiqdio_free_memory(void)
273 {
274 	kfree(q_indicators);
275 }
276 
277 int __init tiqdio_register_thinints(void)
278 {
279 	isc_register(QDIO_AIRQ_ISC);
280 	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
281 						      NULL, QDIO_AIRQ_ISC);
282 	if (IS_ERR(tiqdio_alsi)) {
283 		DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
284 		tiqdio_alsi = NULL;
285 		isc_unregister(QDIO_AIRQ_ISC);
286 		return -ENOMEM;
287 	}
288 	return 0;
289 }
290 
291 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
292 {
293 	if (!is_thinint_irq(irq_ptr))
294 		return 0;
295 	return set_subchannel_ind(irq_ptr, 0);
296 }
297 
298 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
299 {
300 	if (!is_thinint_irq(irq_ptr))
301 		return;
302 	irq_ptr->dsci = get_indicator();
303 	DBF_HEX(&irq_ptr->dsci, sizeof(void *));
304 }
305 
306 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
307 {
308 	if (!is_thinint_irq(irq_ptr))
309 		return;
310 
311 	/* reset adapter interrupt indicators */
312 	set_subchannel_ind(irq_ptr, 1);
313 	put_indicator(irq_ptr->dsci);
314 }
315 
316 void __exit tiqdio_unregister_thinints(void)
317 {
318 	WARN_ON(!list_empty(&tiq_list));
319 
320 	if (tiqdio_alsi) {
321 		s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
322 		isc_unregister(QDIO_AIRQ_ISC);
323 	}
324 }
325