[S390] sparse: fix sparse static warnings
[linux-2.6.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
30 /* list of thin interrupt input queues */
31 static LIST_HEAD(tiq_list);
32 static DEFINE_MUTEX(tiq_list_lock);
33
34 /* adapter local summary indicator */
35 static u8 *tiqdio_alsi;
36
37 struct indicator_t *q_indicators;
38
39 u64 last_ai_time;
40
41 /* returns addr for the device state change indicator */
42 static u32 *get_indicator(void)
43 {
44         int i;
45
46         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
47                 if (!atomic_read(&q_indicators[i].count)) {
48                         atomic_set(&q_indicators[i].count, 1);
49                         return &q_indicators[i].ind;
50                 }
51
52         /* use the shared indicator */
53         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
54         return &q_indicators[TIQDIO_SHARED_IND].ind;
55 }
56
57 static void put_indicator(u32 *addr)
58 {
59         int i;
60
61         if (!addr)
62                 return;
63         i = ((unsigned long)addr - (unsigned long)q_indicators) /
64                 sizeof(struct indicator_t);
65         atomic_dec(&q_indicators[i].count);
66 }
67
68 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
69 {
70         mutex_lock(&tiq_list_lock);
71         BUG_ON(irq_ptr->nr_input_qs < 1);
72         list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
73         mutex_unlock(&tiq_list_lock);
74         xchg(irq_ptr->dsci, 1 << 7);
75 }
76
77 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
78 {
79         struct qdio_q *q;
80
81         BUG_ON(irq_ptr->nr_input_qs < 1);
82         q = irq_ptr->input_qs[0];
83         /* if establish triggered an error */
84         if (!q || !q->entry.prev || !q->entry.next)
85                 return;
86
87         mutex_lock(&tiq_list_lock);
88         list_del_rcu(&q->entry);
89         mutex_unlock(&tiq_list_lock);
90         synchronize_rcu();
91 }
92
93 static inline u32 clear_shared_ind(void)
94 {
95         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
96                 return 0;
97         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
98 }
99
100 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
101 {
102         struct qdio_q *q;
103         int i;
104
105         for_each_input_queue(irq, q, i) {
106                 if (!references_shared_dsci(irq) &&
107                     has_multiple_inq_on_dsci(irq))
108                         xchg(q->irq_ptr->dsci, 0);
109
110                 if (q->u.in.queue_start_poll) {
111                         /* skip if polling is enabled or already in work */
112                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
113                                              &q->u.in.queue_irq_state)) {
114                                 qperf_inc(q, int_discarded);
115                                 continue;
116                         }
117
118                         /* avoid dsci clear here, done after processing */
119                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
120                                                  q->irq_ptr->int_parm);
121                 } else {
122                         if (!shared_ind(q))
123                                 xchg(q->irq_ptr->dsci, 0);
124
125                         /*
126                          * Call inbound processing but not directly
127                          * since that could starve other thinint queues.
128                          */
129                         tasklet_schedule(&q->tasklet);
130                 }
131         }
132 }
133
134 /**
135  * tiqdio_thinint_handler - thin interrupt handler for qdio
136  * @alsi: pointer to adapter local summary indicator
137  * @data: NULL
138  */
139 static void tiqdio_thinint_handler(void *alsi, void *data)
140 {
141         u32 si_used = clear_shared_ind();
142         struct qdio_q *q;
143
144         last_ai_time = S390_lowcore.int_clock;
145         kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
146
147         /* protect tiq_list entries, only changed in activate or shutdown */
148         rcu_read_lock();
149
150         /* check for work on all inbound thinint queues */
151         list_for_each_entry_rcu(q, &tiq_list, entry) {
152                 struct qdio_irq *irq;
153
154                 /* only process queues from changed sets */
155                 irq = q->irq_ptr;
156                 if (unlikely(references_shared_dsci(irq))) {
157                         if (!si_used)
158                                 continue;
159                 } else if (!*irq->dsci)
160                         continue;
161
162                 tiqdio_call_inq_handlers(irq);
163
164                 qperf_inc(q, adapter_int);
165         }
166         rcu_read_unlock();
167 }
168
169 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
170 {
171         struct scssc_area *scssc_area;
172         int rc;
173
174         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
175         memset(scssc_area, 0, PAGE_SIZE);
176
177         if (reset) {
178                 scssc_area->summary_indicator_addr = 0;
179                 scssc_area->subchannel_indicator_addr = 0;
180         } else {
181                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
182                 scssc_area->subchannel_indicator_addr =
183                         virt_to_phys(irq_ptr->dsci);
184         }
185
186         scssc_area->request = (struct chsc_header) {
187                 .length = 0x0fe0,
188                 .code   = 0x0021,
189         };
190         scssc_area->operation_code = 0;
191         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
192         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
193         scssc_area->isc = QDIO_AIRQ_ISC;
194         scssc_area->schid = irq_ptr->schid;
195
196         /* enable the time delay disablement facility */
197         if (css_general_characteristics.aif_tdd)
198                 scssc_area->word_with_d_bit = 0x10000000;
199
200         rc = chsc(scssc_area);
201         if (rc)
202                 return -EIO;
203
204         rc = chsc_error_from_response(scssc_area->response.code);
205         if (rc) {
206                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
207                           scssc_area->response.code);
208                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
209                 return rc;
210         }
211
212         DBF_EVENT("setscind");
213         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
214         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
215         return 0;
216 }
217
218 /* allocate non-shared indicators and shared indicator */
219 int __init tiqdio_allocate_memory(void)
220 {
221         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
222                              GFP_KERNEL);
223         if (!q_indicators)
224                 return -ENOMEM;
225         return 0;
226 }
227
228 void tiqdio_free_memory(void)
229 {
230         kfree(q_indicators);
231 }
232
233 int __init tiqdio_register_thinints(void)
234 {
235         isc_register(QDIO_AIRQ_ISC);
236         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
237                                                       NULL, QDIO_AIRQ_ISC);
238         if (IS_ERR(tiqdio_alsi)) {
239                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
240                 tiqdio_alsi = NULL;
241                 isc_unregister(QDIO_AIRQ_ISC);
242                 return -ENOMEM;
243         }
244         return 0;
245 }
246
247 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
248 {
249         if (!is_thinint_irq(irq_ptr))
250                 return 0;
251         return set_subchannel_ind(irq_ptr, 0);
252 }
253
254 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
255 {
256         if (!is_thinint_irq(irq_ptr))
257                 return;
258         irq_ptr->dsci = get_indicator();
259         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
260 }
261
262 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
263 {
264         if (!is_thinint_irq(irq_ptr))
265                 return;
266
267         /* reset adapter interrupt indicators */
268         set_subchannel_ind(irq_ptr, 1);
269         put_indicator(irq_ptr->dsci);
270 }
271
272 void __exit tiqdio_unregister_thinints(void)
273 {
274         WARN_ON(!list_empty(&tiq_list));
275
276         if (tiqdio_alsi) {
277                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
278                 isc_unregister(QDIO_AIRQ_ISC);
279         }
280 }