011eadea3ee422fabb85ef24caa784401682ff89
[pandora-kernel.git] / drivers / s390 / cio / qdio_thinint.c
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 }