1 /* 2 * linux/drivers/s390/cio/thinint_qdio.c 3 * 4 * thin interrupt support for qdio 5 * 6 * Copyright 2000-2008 IBM Corp. 7 * Author(s): Utz Bacher <utz.bacher@de.ibm.com> 8 * Cornelia Huck <cornelia.huck@de.ibm.com> 9 * Jan Glauber <jang@linux.vnet.ibm.com> 10 */ 11 #include <linux/io.h> 12 #include <asm/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 #include "qdio_perf.h" 23 24 /* 25 * Restriction: only 63 iqdio subchannels would have its own indicator, 26 * after that, subsequent subchannels share one indicator 27 */ 28 #define TIQDIO_NR_NONSHARED_IND 63 29 #define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1) 30 #define TIQDIO_SHARED_IND 63 31 32 /* list of thin interrupt input queues */ 33 static LIST_HEAD(tiq_list); 34 DEFINE_MUTEX(tiq_list_lock); 35 36 /* adapter local summary indicator */ 37 static unsigned char *tiqdio_alsi; 38 39 /* device state change indicators */ 40 struct indicator_t { 41 u32 ind; /* u32 because of compare-and-swap performance */ 42 atomic_t count; /* use count, 0 or 1 for non-shared indicators */ 43 }; 44 static struct indicator_t *q_indicators; 45 46 static int css_qdio_omit_svs; 47 48 static inline unsigned long do_clear_global_summary(void) 49 { 50 register unsigned long __fn asm("1") = 3; 51 register unsigned long __tmp asm("2"); 52 register unsigned long __time asm("3"); 53 54 asm volatile( 55 " .insn rre,0xb2650000,2,0" 56 : "+d" (__fn), "=d" (__tmp), "=d" (__time)); 57 return __time; 58 } 59 60 /* returns addr for the device state change indicator */ 61 static u32 *get_indicator(void) 62 { 63 int i; 64 65 for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++) 66 if (!atomic_read(&q_indicators[i].count)) { 67 atomic_set(&q_indicators[i].count, 1); 68 return &q_indicators[i].ind; 69 } 70 71 /* use the shared indicator */ 72 atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count); 73 return &q_indicators[TIQDIO_SHARED_IND].ind; 74 } 75 76 static void put_indicator(u32 *addr) 77 { 78 int i; 79 80 if (!addr) 81 return; 82 i = ((unsigned long)addr - (unsigned long)q_indicators) / 83 sizeof(struct indicator_t); 84 atomic_dec(&q_indicators[i].count); 85 } 86 87 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr) 88 { 89 struct qdio_q *q; 90 int i; 91 92 /* No TDD facility? If we must use SIGA-s we can also omit SVS. */ 93 if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync) 94 css_qdio_omit_svs = 1; 95 96 mutex_lock(&tiq_list_lock); 97 for_each_input_queue(irq_ptr, q, i) 98 list_add_rcu(&q->entry, &tiq_list); 99 mutex_unlock(&tiq_list_lock); 100 xchg(irq_ptr->dsci, 1); 101 } 102 103 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr) 104 { 105 struct qdio_q *q; 106 int i; 107 108 for (i = 0; i < irq_ptr->nr_input_qs; i++) { 109 q = irq_ptr->input_qs[i]; 110 /* if establish triggered an error */ 111 if (!q || !q->entry.prev || !q->entry.next) 112 continue; 113 114 mutex_lock(&tiq_list_lock); 115 list_del_rcu(&q->entry); 116 mutex_unlock(&tiq_list_lock); 117 synchronize_rcu(); 118 } 119 } 120 121 static inline int shared_ind(struct qdio_irq *irq_ptr) 122 { 123 return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind; 124 } 125 126 /** 127 * tiqdio_thinint_handler - thin interrupt handler for qdio 128 * @ind: pointer to adapter local summary indicator 129 * @drv_data: NULL 130 */ 131 static void tiqdio_thinint_handler(void *ind, void *drv_data) 132 { 133 struct qdio_q *q; 134 135 qdio_perf_stat_inc(&perf_stats.thin_int); 136 137 /* 138 * SVS only when needed: issue SVS to benefit from iqdio interrupt 139 * avoidance (SVS clears adapter interrupt suppression overwrite) 140 */ 141 if (!css_qdio_omit_svs) 142 do_clear_global_summary(); 143 144 /* 145 * reset local summary indicator (tiqdio_alsi) to stop adapter 146 * interrupts for now 147 */ 148 xchg((u8 *)ind, 0); 149 150 /* protect tiq_list entries, only changed in activate or shutdown */ 151 rcu_read_lock(); 152 153 /* check for work on all inbound thinint queues */ 154 list_for_each_entry_rcu(q, &tiq_list, entry) 155 /* only process queues from changed sets */ 156 if (*q->irq_ptr->dsci) { 157 158 /* only clear it if the indicator is non-shared */ 159 if (!shared_ind(q->irq_ptr)) 160 xchg(q->irq_ptr->dsci, 0); 161 /* 162 * don't call inbound processing directly since 163 * that could starve other thinint queues 164 */ 165 tasklet_schedule(&q->tasklet); 166 } 167 168 rcu_read_unlock(); 169 170 /* 171 * if we used the shared indicator clear it now after all queues 172 * were processed 173 */ 174 if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) { 175 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0); 176 177 /* prevent racing */ 178 if (*tiqdio_alsi) 179 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1); 180 } 181 } 182 183 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset) 184 { 185 struct scssc_area *scssc_area; 186 int rc; 187 188 scssc_area = (struct scssc_area *)irq_ptr->chsc_page; 189 memset(scssc_area, 0, PAGE_SIZE); 190 191 if (reset) { 192 scssc_area->summary_indicator_addr = 0; 193 scssc_area->subchannel_indicator_addr = 0; 194 } else { 195 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi); 196 scssc_area->subchannel_indicator_addr = 197 virt_to_phys(irq_ptr->dsci); 198 } 199 200 scssc_area->request = (struct chsc_header) { 201 .length = 0x0fe0, 202 .code = 0x0021, 203 }; 204 scssc_area->operation_code = 0; 205 scssc_area->ks = PAGE_DEFAULT_KEY; 206 scssc_area->kc = PAGE_DEFAULT_KEY; 207 scssc_area->isc = QDIO_AIRQ_ISC; 208 scssc_area->schid = irq_ptr->schid; 209 210 /* enable the time delay disablement facility */ 211 if (css_general_characteristics.aif_tdd) 212 scssc_area->word_with_d_bit = 0x10000000; 213 214 rc = chsc(scssc_area); 215 if (rc) 216 return -EIO; 217 218 rc = chsc_error_from_response(scssc_area->response.code); 219 if (rc) { 220 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no, 221 scssc_area->response.code); 222 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *)); 223 return rc; 224 } 225 226 DBF_EVENT("setscind"); 227 DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long)); 228 DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long)); 229 return 0; 230 } 231 232 /* allocate non-shared indicators and shared indicator */ 233 int __init tiqdio_allocate_memory(void) 234 { 235 q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS, 236 GFP_KERNEL); 237 if (!q_indicators) 238 return -ENOMEM; 239 return 0; 240 } 241 242 void tiqdio_free_memory(void) 243 { 244 kfree(q_indicators); 245 } 246 247 int __init tiqdio_register_thinints(void) 248 { 249 isc_register(QDIO_AIRQ_ISC); 250 tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler, 251 NULL, QDIO_AIRQ_ISC); 252 if (IS_ERR(tiqdio_alsi)) { 253 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi)); 254 tiqdio_alsi = NULL; 255 isc_unregister(QDIO_AIRQ_ISC); 256 return -ENOMEM; 257 } 258 return 0; 259 } 260 261 int qdio_establish_thinint(struct qdio_irq *irq_ptr) 262 { 263 if (!is_thinint_irq(irq_ptr)) 264 return 0; 265 266 /* Check for aif time delay disablement. If installed, 267 * omit SVS even under LPAR 268 */ 269 if (css_general_characteristics.aif_tdd) 270 css_qdio_omit_svs = 1; 271 return set_subchannel_ind(irq_ptr, 0); 272 } 273 274 void qdio_setup_thinint(struct qdio_irq *irq_ptr) 275 { 276 if (!is_thinint_irq(irq_ptr)) 277 return; 278 irq_ptr->dsci = get_indicator(); 279 DBF_HEX(&irq_ptr->dsci, sizeof(void *)); 280 } 281 282 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr) 283 { 284 if (!is_thinint_irq(irq_ptr)) 285 return; 286 287 /* reset adapter interrupt indicators */ 288 put_indicator(irq_ptr->dsci); 289 set_subchannel_ind(irq_ptr, 1); 290 } 291 292 void __exit tiqdio_unregister_thinints(void) 293 { 294 WARN_ON(!list_empty(&tiq_list)); 295 296 if (tiqdio_alsi) { 297 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC); 298 isc_unregister(QDIO_AIRQ_ISC); 299 } 300 } 301