xref: /openbmc/linux/drivers/s390/cio/qdio_thinint.c (revision b6dcefde)
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 <asm/atomic.h>
11 #include <asm/debug.h>
12 #include <asm/qdio.h>
13 #include <asm/airq.h>
14 #include <asm/isc.h>
15 
16 #include "cio.h"
17 #include "ioasm.h"
18 #include "qdio.h"
19 #include "qdio_debug.h"
20 
21 /*
22  * Restriction: only 63 iqdio subchannels would have its own indicator,
23  * after that, subsequent subchannels share one indicator
24  */
25 #define TIQDIO_NR_NONSHARED_IND		63
26 #define TIQDIO_NR_INDICATORS		(TIQDIO_NR_NONSHARED_IND + 1)
27 #define TIQDIO_SHARED_IND		63
28 
29 /* list of thin interrupt input queues */
30 static LIST_HEAD(tiq_list);
31 DEFINE_MUTEX(tiq_list_lock);
32 
33 /* adapter local summary indicator */
34 static unsigned char *tiqdio_alsi;
35 
36 /* device state change indicators */
37 struct indicator_t {
38 	u32 ind;	/* u32 because of compare-and-swap performance */
39 	atomic_t count; /* use count, 0 or 1 for non-shared indicators */
40 };
41 static struct indicator_t *q_indicators;
42 
43 static int css_qdio_omit_svs;
44 
45 static inline unsigned long do_clear_global_summary(void)
46 {
47 	register unsigned long __fn asm("1") = 3;
48 	register unsigned long __tmp asm("2");
49 	register unsigned long __time asm("3");
50 
51 	asm volatile(
52 		"	.insn	rre,0xb2650000,2,0"
53 		: "+d" (__fn), "=d" (__tmp), "=d" (__time));
54 	return __time;
55 }
56 
57 /* returns addr for the device state change indicator */
58 static u32 *get_indicator(void)
59 {
60 	int i;
61 
62 	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
63 		if (!atomic_read(&q_indicators[i].count)) {
64 			atomic_set(&q_indicators[i].count, 1);
65 			return &q_indicators[i].ind;
66 		}
67 
68 	/* use the shared indicator */
69 	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
70 	return &q_indicators[TIQDIO_SHARED_IND].ind;
71 }
72 
73 static void put_indicator(u32 *addr)
74 {
75 	int i;
76 
77 	if (!addr)
78 		return;
79 	i = ((unsigned long)addr - (unsigned long)q_indicators) /
80 		sizeof(struct indicator_t);
81 	atomic_dec(&q_indicators[i].count);
82 }
83 
84 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
85 {
86 	struct qdio_q *q;
87 	int i;
88 
89 	/* No TDD facility? If we must use SIGA-s we can also omit SVS. */
90 	if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
91 		css_qdio_omit_svs = 1;
92 
93 	mutex_lock(&tiq_list_lock);
94 	for_each_input_queue(irq_ptr, q, i)
95 		list_add_rcu(&q->entry, &tiq_list);
96 	mutex_unlock(&tiq_list_lock);
97 	xchg(irq_ptr->dsci, 1);
98 }
99 
100 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
101 {
102 	struct qdio_q *q;
103 	int i;
104 
105 	for (i = 0; i < irq_ptr->nr_input_qs; i++) {
106 		q = irq_ptr->input_qs[i];
107 		/* if establish triggered an error */
108 		if (!q || !q->entry.prev || !q->entry.next)
109 			continue;
110 
111 		mutex_lock(&tiq_list_lock);
112 		list_del_rcu(&q->entry);
113 		mutex_unlock(&tiq_list_lock);
114 		synchronize_rcu();
115 	}
116 }
117 
118 static inline int shared_ind(struct qdio_irq *irq_ptr)
119 {
120 	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
121 }
122 
123 /**
124  * tiqdio_thinint_handler - thin interrupt handler for qdio
125  * @ind: pointer to adapter local summary indicator
126  * @drv_data: NULL
127  */
128 static void tiqdio_thinint_handler(void *ind, void *drv_data)
129 {
130 	struct qdio_q *q;
131 
132 	/*
133 	 * SVS only when needed: issue SVS to benefit from iqdio interrupt
134 	 * avoidance (SVS clears adapter interrupt suppression overwrite)
135 	 */
136 	if (!css_qdio_omit_svs)
137 		do_clear_global_summary();
138 
139 	/*
140 	 * reset local summary indicator (tiqdio_alsi) to stop adapter
141 	 * interrupts for now
142 	 */
143 	xchg((u8 *)ind, 0);
144 
145 	/* protect tiq_list entries, only changed in activate or shutdown */
146 	rcu_read_lock();
147 
148 	/* check for work on all inbound thinint queues */
149 	list_for_each_entry_rcu(q, &tiq_list, entry)
150 		/* only process queues from changed sets */
151 		if (*q->irq_ptr->dsci) {
152 			qperf_inc(q, adapter_int);
153 
154 			/* only clear it if the indicator is non-shared */
155 			if (!shared_ind(q->irq_ptr))
156 				xchg(q->irq_ptr->dsci, 0);
157 			/*
158 			 * don't call inbound processing directly since
159 			 * that could starve other thinint queues
160 			 */
161 			tasklet_schedule(&q->tasklet);
162 		}
163 
164 	rcu_read_unlock();
165 
166 	/*
167 	 * if we used the shared indicator clear it now after all queues
168 	 * were processed
169 	 */
170 	if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
171 		xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
172 
173 		/* prevent racing */
174 		if (*tiqdio_alsi)
175 			xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
176 	}
177 }
178 
179 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
180 {
181 	struct scssc_area *scssc_area;
182 	int rc;
183 
184 	scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
185 	memset(scssc_area, 0, PAGE_SIZE);
186 
187 	if (reset) {
188 		scssc_area->summary_indicator_addr = 0;
189 		scssc_area->subchannel_indicator_addr = 0;
190 	} else {
191 		scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
192 		scssc_area->subchannel_indicator_addr =
193 			virt_to_phys(irq_ptr->dsci);
194 	}
195 
196 	scssc_area->request = (struct chsc_header) {
197 		.length = 0x0fe0,
198 		.code	= 0x0021,
199 	};
200 	scssc_area->operation_code = 0;
201 	scssc_area->ks = PAGE_DEFAULT_KEY;
202 	scssc_area->kc = PAGE_DEFAULT_KEY;
203 	scssc_area->isc = QDIO_AIRQ_ISC;
204 	scssc_area->schid = irq_ptr->schid;
205 
206 	/* enable the time delay disablement facility */
207 	if (css_general_characteristics.aif_tdd)
208 		scssc_area->word_with_d_bit = 0x10000000;
209 
210 	rc = chsc(scssc_area);
211 	if (rc)
212 		return -EIO;
213 
214 	rc = chsc_error_from_response(scssc_area->response.code);
215 	if (rc) {
216 		DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
217 			  scssc_area->response.code);
218 		DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
219 		return rc;
220 	}
221 
222 	DBF_EVENT("setscind");
223 	DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
224 	DBF_HEX(&scssc_area->subchannel_indicator_addr,	sizeof(unsigned long));
225 	return 0;
226 }
227 
228 /* allocate non-shared indicators and shared indicator */
229 int __init tiqdio_allocate_memory(void)
230 {
231 	q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
232 			     GFP_KERNEL);
233 	if (!q_indicators)
234 		return -ENOMEM;
235 	return 0;
236 }
237 
238 void tiqdio_free_memory(void)
239 {
240 	kfree(q_indicators);
241 }
242 
243 int __init tiqdio_register_thinints(void)
244 {
245 	isc_register(QDIO_AIRQ_ISC);
246 	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
247 						      NULL, QDIO_AIRQ_ISC);
248 	if (IS_ERR(tiqdio_alsi)) {
249 		DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
250 		tiqdio_alsi = NULL;
251 		isc_unregister(QDIO_AIRQ_ISC);
252 		return -ENOMEM;
253 	}
254 	return 0;
255 }
256 
257 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
258 {
259 	if (!is_thinint_irq(irq_ptr))
260 		return 0;
261 
262 	/* Check for aif time delay disablement. If installed,
263 	 * omit SVS even under LPAR
264 	 */
265 	if (css_general_characteristics.aif_tdd)
266 		css_qdio_omit_svs = 1;
267 	return set_subchannel_ind(irq_ptr, 0);
268 }
269 
270 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
271 {
272 	if (!is_thinint_irq(irq_ptr))
273 		return;
274 	irq_ptr->dsci = get_indicator();
275 	DBF_HEX(&irq_ptr->dsci, sizeof(void *));
276 }
277 
278 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
279 {
280 	if (!is_thinint_irq(irq_ptr))
281 		return;
282 
283 	/* reset adapter interrupt indicators */
284 	put_indicator(irq_ptr->dsci);
285 	set_subchannel_ind(irq_ptr, 1);
286 }
287 
288 void __exit tiqdio_unregister_thinints(void)
289 {
290 	WARN_ON(!list_empty(&tiq_list));
291 
292 	if (tiqdio_alsi) {
293 		s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
294 		isc_unregister(QDIO_AIRQ_ISC);
295 	}
296 }
297