1 /* 2 * Copyright IBM Corp. 2000, 2009 3 * Author(s): Utz Bacher <utz.bacher@de.ibm.com> 4 * Cornelia Huck <cornelia.huck@de.ibm.com> 5 * Jan Glauber <jang@linux.vnet.ibm.com> 6 */ 7 #include <linux/io.h> 8 #include <linux/slab.h> 9 #include <linux/kernel_stat.h> 10 #include <linux/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 /* device state change indicators */ 30 struct indicator_t { 31 u32 ind; /* u32 because of compare-and-swap performance */ 32 atomic_t count; /* use count, 0 or 1 for non-shared indicators */ 33 }; 34 35 /* list of thin interrupt input queues */ 36 static LIST_HEAD(tiq_list); 37 static DEFINE_MUTEX(tiq_list_lock); 38 39 /* Adapter interrupt definitions */ 40 static void tiqdio_thinint_handler(struct airq_struct *airq); 41 42 static struct airq_struct tiqdio_airq = { 43 .handler = tiqdio_thinint_handler, 44 .isc = QDIO_AIRQ_ISC, 45 }; 46 47 static struct indicator_t *q_indicators; 48 49 u64 last_ai_time; 50 51 /* returns addr for the device state change indicator */ 52 static u32 *get_indicator(void) 53 { 54 int i; 55 56 for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++) 57 if (!atomic_read(&q_indicators[i].count)) { 58 atomic_set(&q_indicators[i].count, 1); 59 return &q_indicators[i].ind; 60 } 61 62 /* use the shared indicator */ 63 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count); 64 return &q_indicators[TIQDIO_SHARED_IND].ind; 65 } 66 67 static void put_indicator(u32 *addr) 68 { 69 int i; 70 71 if (!addr) 72 return; 73 i = ((unsigned long)addr - (unsigned long)q_indicators) / 74 sizeof(struct indicator_t); 75 atomic_dec(&q_indicators[i].count); 76 } 77 78 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr) 79 { 80 mutex_lock(&tiq_list_lock); 81 list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list); 82 mutex_unlock(&tiq_list_lock); 83 xchg(irq_ptr->dsci, 1 << 7); 84 } 85 86 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr) 87 { 88 struct qdio_q *q; 89 90 q = irq_ptr->input_qs[0]; 91 /* if establish triggered an error */ 92 if (!q || !q->entry.prev || !q->entry.next) 93 return; 94 95 mutex_lock(&tiq_list_lock); 96 list_del_rcu(&q->entry); 97 mutex_unlock(&tiq_list_lock); 98 synchronize_rcu(); 99 } 100 101 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr) 102 { 103 return irq_ptr->nr_input_qs > 1; 104 } 105 106 static inline int references_shared_dsci(struct qdio_irq *irq_ptr) 107 { 108 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind; 109 } 110 111 static inline int shared_ind(struct qdio_irq *irq_ptr) 112 { 113 return references_shared_dsci(irq_ptr) || 114 has_multiple_inq_on_dsci(irq_ptr); 115 } 116 117 void clear_nonshared_ind(struct qdio_irq *irq_ptr) 118 { 119 if (!is_thinint_irq(irq_ptr)) 120 return; 121 if (shared_ind(irq_ptr)) 122 return; 123 xchg(irq_ptr->dsci, 0); 124 } 125 126 int test_nonshared_ind(struct qdio_irq *irq_ptr) 127 { 128 if (!is_thinint_irq(irq_ptr)) 129 return 0; 130 if (shared_ind(irq_ptr)) 131 return 0; 132 if (*irq_ptr->dsci) 133 return 1; 134 else 135 return 0; 136 } 137 138 static inline u32 clear_shared_ind(void) 139 { 140 if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) 141 return 0; 142 return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0); 143 } 144 145 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq) 146 { 147 struct qdio_q *q; 148 int i; 149 150 for_each_input_queue(irq, q, i) { 151 if (!references_shared_dsci(irq) && 152 has_multiple_inq_on_dsci(irq)) 153 xchg(q->irq_ptr->dsci, 0); 154 155 if (q->u.in.queue_start_poll) { 156 /* skip if polling is enabled or already in work */ 157 if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED, 158 &q->u.in.queue_irq_state)) { 159 qperf_inc(q, int_discarded); 160 continue; 161 } 162 163 /* avoid dsci clear here, done after processing */ 164 q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr, 165 q->irq_ptr->int_parm); 166 } else { 167 if (!shared_ind(q->irq_ptr)) 168 xchg(q->irq_ptr->dsci, 0); 169 170 /* 171 * Call inbound processing but not directly 172 * since that could starve other thinint queues. 173 */ 174 tasklet_schedule(&q->tasklet); 175 } 176 } 177 } 178 179 /** 180 * tiqdio_thinint_handler - thin interrupt handler for qdio 181 * @alsi: pointer to adapter local summary indicator 182 * @data: NULL 183 */ 184 static void tiqdio_thinint_handler(struct airq_struct *airq) 185 { 186 u32 si_used = clear_shared_ind(); 187 struct qdio_q *q; 188 189 last_ai_time = S390_lowcore.int_clock; 190 inc_irq_stat(IRQIO_QAI); 191 192 /* protect tiq_list entries, only changed in activate or shutdown */ 193 rcu_read_lock(); 194 195 /* check for work on all inbound thinint queues */ 196 list_for_each_entry_rcu(q, &tiq_list, entry) { 197 struct qdio_irq *irq; 198 199 /* only process queues from changed sets */ 200 irq = q->irq_ptr; 201 if (unlikely(references_shared_dsci(irq))) { 202 if (!si_used) 203 continue; 204 } else if (!*irq->dsci) 205 continue; 206 207 tiqdio_call_inq_handlers(irq); 208 209 qperf_inc(q, adapter_int); 210 } 211 rcu_read_unlock(); 212 } 213 214 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset) 215 { 216 struct chsc_scssc_area *scssc = (void *)irq_ptr->chsc_page; 217 u64 summary_indicator_addr, subchannel_indicator_addr; 218 int rc; 219 220 if (reset) { 221 summary_indicator_addr = 0; 222 subchannel_indicator_addr = 0; 223 } else { 224 summary_indicator_addr = virt_to_phys(tiqdio_airq.lsi_ptr); 225 subchannel_indicator_addr = virt_to_phys(irq_ptr->dsci); 226 } 227 228 rc = chsc_sadc(irq_ptr->schid, scssc, summary_indicator_addr, 229 subchannel_indicator_addr); 230 if (rc) { 231 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no, 232 scssc->response.code); 233 goto out; 234 } 235 236 DBF_EVENT("setscind"); 237 DBF_HEX(&summary_indicator_addr, sizeof(summary_indicator_addr)); 238 DBF_HEX(&subchannel_indicator_addr, sizeof(subchannel_indicator_addr)); 239 out: 240 return rc; 241 } 242 243 /* allocate non-shared indicators and shared indicator */ 244 int __init tiqdio_allocate_memory(void) 245 { 246 q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS, 247 GFP_KERNEL); 248 if (!q_indicators) 249 return -ENOMEM; 250 return 0; 251 } 252 253 void tiqdio_free_memory(void) 254 { 255 kfree(q_indicators); 256 } 257 258 int __init tiqdio_register_thinints(void) 259 { 260 int rc; 261 262 rc = register_adapter_interrupt(&tiqdio_airq); 263 if (rc) { 264 DBF_EVENT("RTI:%x", rc); 265 return rc; 266 } 267 return 0; 268 } 269 270 int qdio_establish_thinint(struct qdio_irq *irq_ptr) 271 { 272 if (!is_thinint_irq(irq_ptr)) 273 return 0; 274 return set_subchannel_ind(irq_ptr, 0); 275 } 276 277 void qdio_setup_thinint(struct qdio_irq *irq_ptr) 278 { 279 if (!is_thinint_irq(irq_ptr)) 280 return; 281 irq_ptr->dsci = get_indicator(); 282 DBF_HEX(&irq_ptr->dsci, sizeof(void *)); 283 } 284 285 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr) 286 { 287 if (!is_thinint_irq(irq_ptr)) 288 return; 289 290 /* reset adapter interrupt indicators */ 291 set_subchannel_ind(irq_ptr, 1); 292 put_indicator(irq_ptr->dsci); 293 } 294 295 void __exit tiqdio_unregister_thinints(void) 296 { 297 WARN_ON(!list_empty(&tiq_list)); 298 unregister_adapter_interrupt(&tiqdio_airq); 299 } 300