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 */
get_indicator(void)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
put_indicator(u32 * addr)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
tiqdio_add_input_queues(struct qdio_irq * irq_ptr)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
tiqdio_remove_input_queues(struct qdio_irq * irq_ptr)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
has_multiple_inq_on_dsci(struct qdio_irq * irq_ptr)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
references_shared_dsci(struct qdio_irq * irq_ptr)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
shared_ind(struct qdio_irq * irq_ptr)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
clear_nonshared_ind(struct qdio_irq * irq_ptr)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
test_nonshared_ind(struct qdio_irq * irq_ptr)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
clear_shared_ind(void)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
tiqdio_call_inq_handlers(struct qdio_irq * irq)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 */
tiqdio_thinint_handler(void * alsi,void * data)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
set_subchannel_ind(struct qdio_irq * irq_ptr,int reset)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 */
tiqdio_allocate_memory(void)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
tiqdio_free_memory(void)272 void tiqdio_free_memory(void)
273 {
274 kfree(q_indicators);
275 }
276
tiqdio_register_thinints(void)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
qdio_establish_thinint(struct qdio_irq * irq_ptr)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
qdio_setup_thinint(struct qdio_irq * irq_ptr)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
qdio_shutdown_thinint(struct qdio_irq * irq_ptr)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
tiqdio_unregister_thinints(void)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