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