drivers/s390/cio/qdio_thinint.c

   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
  35 /* adapter local summary indicator */
  36 static unsigned char *tiqdio_alsi;
  37
  38 /* device state change indicators */
  39 struct indicator_t {
  40         u32 ind;        /* u32 because of compare-and-swap performance */
  41         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  42 };
  43 static struct indicator_t *q_indicators;
  44
  45 static void tiqdio_tasklet_fn(unsigned long data);
  46 static DECLARE_TASKLET(tiqdio_tasklet, tiqdio_tasklet_fn, 0);
  47
  48 static int css_qdio_omit_svs;
  49
  50 static inline unsigned long do_clear_global_summary(void)
  51 {
  52         register unsigned long __fn asm("1") = 3;
  53         register unsigned long __tmp asm("2");
  54         register unsigned long __time asm("3");
  55
  56         asm volatile(
  57                 "       .insn   rre,0xb2650000,2,0"
  58                 : "+d" (__fn), "=d" (__tmp), "=d" (__time));
  59         return __time;
  60 }
  61
  62 /* returns addr for the device state change indicator */
  63 static u32 *get_indicator(void)
  64 {
  65         int i;
  66
  67         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  68                 if (!atomic_read(&q_indicators[i].count)) {
  69                         atomic_set(&q_indicators[i].count, 1);
  70                         return &q_indicators[i].ind;
  71                 }
  72
  73         /* use the shared indicator */
  74         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  75         return &q_indicators[TIQDIO_SHARED_IND].ind;
  76 }
  77
  78 static void put_indicator(u32 *addr)
  79 {
  80         int i;
  81
  82         if (!addr)
  83                 return;
  84         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  85                 sizeof(struct indicator_t);
  86         atomic_dec(&q_indicators[i].count);
  87 }
  88
  89 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  90 {
  91         struct qdio_q *q;
  92         int i;
  93
  94         /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
  95         if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
  96                 css_qdio_omit_svs = 1;
  97
  98         for_each_input_queue(irq_ptr, q, i) {
  99                 list_add_rcu(&q->entry, &tiq_list);
 100                 synchronize_rcu();
 101         }
 102         xchg(irq_ptr->dsci, 1);
 103         tasklet_schedule(&tiqdio_tasklet);
 104 }
 105
 106 /*
 107  * we cannot stop the tiqdio tasklet here since it is for all
 108  * thinint qdio devices and it must run as long as there is a
 109  * thinint device left
 110  */
 111 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
 112 {
 113         struct qdio_q *q;
 114         int i;
 115
 116         for_each_input_queue(irq_ptr, q, i) {
 117                 list_del_rcu(&q->entry);
 118                 synchronize_rcu();
 119         }
 120 }
 121
 122 static inline int tiqdio_inbound_q_done(struct qdio_q *q)
 123 {
 124         unsigned char state;
 125
 126         if (!atomic_read(&q->nr_buf_used))
 127                 return 1;
 128
 129         qdio_siga_sync_q(q);
 130         get_buf_state(q, q->first_to_check, &state);
 131
 132         if (state == SLSB_P_INPUT_PRIMED)
 133                 /* more work coming */
 134                 return 0;
 135         return 1;
 136 }
 137
 138 static inline int shared_ind(struct qdio_irq *irq_ptr)
 139 {
 140         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 141 }
 142
 143 static void __tiqdio_inbound_processing(struct qdio_q *q)
 144 {
 145         qdio_perf_stat_inc(&perf_stats.thinint_inbound);
 146         qdio_sync_after_thinint(q);
 147
 148         /*
 149          * Maybe we have work on our outbound queues... at least
 150          * we have to check the PCI capable queues.
 151          */
 152         qdio_check_outbound_after_thinint(q);
 153
 154 again:
 155         if (!qdio_inbound_q_moved(q))
 156                 return;
 157
 158         qdio_kick_inbound_handler(q);
 159
 160         if (!tiqdio_inbound_q_done(q)) {
 161                 qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
 162                 goto again;
 163         }
 164
 165         qdio_stop_polling(q);
 166         /*
 167          * We need to check again to not lose initiative after
 168          * resetting the ACK state.
 169          */
 170         if (!tiqdio_inbound_q_done(q)) {
 171                 qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
 172                 goto again;
 173         }
 174 }
 175
 176 void tiqdio_inbound_processing(unsigned long data)
 177 {
 178         struct qdio_q *q = (struct qdio_q *)data;
 179
 180         __tiqdio_inbound_processing(q);
 181 }
 182
 183 /* check for work on all inbound thinint queues */
 184 static void tiqdio_tasklet_fn(unsigned long data)
 185 {
 186         struct qdio_q *q;
 187
 188         qdio_perf_stat_inc(&perf_stats.tasklet_thinint);
 189 again:
 190
 191         /* protect tiq_list entries, only changed in activate or shutdown */
 192         rcu_read_lock();
 193
 194         list_for_each_entry_rcu(q, &tiq_list, entry)
 195                 /* only process queues from changed sets */
 196                 if (*q->irq_ptr->dsci) {
 197
 198                         /* only clear it if the indicator is non-shared */
 199                         if (!shared_ind(q->irq_ptr))
 200                                 xchg(q->irq_ptr->dsci, 0);
 201                         /*
 202                          * don't call inbound processing directly since
 203                          * that could starve other thinint queues
 204                          */
 205                         tasklet_schedule(&q->tasklet);
 206                 }
 207
 208         rcu_read_unlock();
 209
 210         /*
 211          * if we used the shared indicator clear it now after all queues
 212          * were processed
 213          */
 214         if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
 215                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 216
 217                 /* prevent racing */
 218                 if (*tiqdio_alsi)
 219                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
 220         }
 221
 222         /* check for more work */
 223         if (*tiqdio_alsi) {
 224                 xchg(tiqdio_alsi, 0);
 225                 qdio_perf_stat_inc(&perf_stats.tasklet_thinint_loop);
 226                 goto again;
 227         }
 228 }
 229
 230 /**
 231  * tiqdio_thinint_handler - thin interrupt handler for qdio
 232  * @ind: pointer to adapter local summary indicator
 233  * @drv_data: NULL
 234  */
 235 static void tiqdio_thinint_handler(void *ind, void *drv_data)
 236 {
 237         qdio_perf_stat_inc(&perf_stats.thin_int);
 238
 239         /*
 240          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 241          * avoidance (SVS clears adapter interrupt suppression overwrite)
 242          */
 243         if (!css_qdio_omit_svs)
 244                 do_clear_global_summary();
 245
 246         /*
 247          * reset local summary indicator (tiqdio_alsi) to stop adapter
 248          * interrupts for now, the tasklet will clean all dsci's
 249          */
 250         xchg((u8 *)ind, 0);
 251         tasklet_hi_schedule(&tiqdio_tasklet);
 252 }
 253
 254 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 255 {
 256         struct scssc_area *scssc_area;
 257         char dbf_text[15];
 258         void *ptr;
 259         int rc;
 260
 261         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 262         memset(scssc_area, 0, PAGE_SIZE);
 263
 264         if (reset) {
 265                 scssc_area->summary_indicator_addr = 0;
 266                 scssc_area->subchannel_indicator_addr = 0;
 267         } else {
 268                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 269                 scssc_area->subchannel_indicator_addr =
 270                         virt_to_phys(irq_ptr->dsci);
 271         }
 272
 273         scssc_area->request = (struct chsc_header) {
 274                 .length = 0x0fe0,
 275                 .code   = 0x0021,
 276         };
 277         scssc_area->operation_code = 0;
 278         scssc_area->ks = PAGE_DEFAULT_KEY;
 279         scssc_area->kc = PAGE_DEFAULT_KEY;
 280         scssc_area->isc = QDIO_AIRQ_ISC;
 281         scssc_area->schid = irq_ptr->schid;
 282
 283         /* enable the time delay disablement facility */
 284         if (css_general_characteristics.aif_tdd)
 285                 scssc_area->word_with_d_bit = 0x10000000;
 286
 287         rc = chsc(scssc_area);
 288         if (rc)
 289                 return -EIO;
 290
 291         rc = chsc_error_from_response(scssc_area->response.code);
 292         if (rc) {
 293                 sprintf(dbf_text, "sidR%4x", scssc_area->response.code);
 294                 QDIO_DBF_TEXT1(0, trace, dbf_text);
 295                 QDIO_DBF_TEXT1(0, setup, dbf_text);
 296                 ptr = &scssc_area->response;
 297                 QDIO_DBF_HEX2(1, setup, &ptr, QDIO_DBF_SETUP_LEN);
 298                 return rc;
 299         }
 300
 301         QDIO_DBF_TEXT2(0, setup, "setscind");
 302         QDIO_DBF_HEX2(0, setup, &scssc_area->summary_indicator_addr,
 303                       sizeof(unsigned long));
 304         QDIO_DBF_HEX2(0, setup, &scssc_area->subchannel_indicator_addr,
 305                       sizeof(unsigned long));
 306         return 0;
 307 }
 308
 309 /* allocate non-shared indicators and shared indicator */
 310 int __init tiqdio_allocate_memory(void)
 311 {
 312         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 313                              GFP_KERNEL);
 314         if (!q_indicators)
 315                 return -ENOMEM;
 316         return 0;
 317 }
 318
 319 void tiqdio_free_memory(void)
 320 {
 321         kfree(q_indicators);
 322 }
 323
 324 int __init tiqdio_register_thinints(void)
 325 {
 326         char dbf_text[20];
 327
 328         isc_register(QDIO_AIRQ_ISC);
 329         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 330                                                       NULL, QDIO_AIRQ_ISC);
 331         if (IS_ERR(tiqdio_alsi)) {
 332                 sprintf(dbf_text, "regthn%lx", PTR_ERR(tiqdio_alsi));
 333                 QDIO_DBF_TEXT0(0, setup, dbf_text);
 334                 tiqdio_alsi = NULL;
 335                 isc_unregister(QDIO_AIRQ_ISC);
 336                 return -ENOMEM;
 337         }
 338         return 0;
 339 }
 340
 341 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 342 {
 343         if (!is_thinint_irq(irq_ptr))
 344                 return 0;
 345
 346         /* Check for aif time delay disablement. If installed,
 347          * omit SVS even under LPAR
 348          */
 349         if (css_general_characteristics.aif_tdd)
 350                 css_qdio_omit_svs = 1;
 351         return set_subchannel_ind(irq_ptr, 0);
 352 }
 353
 354 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 355 {
 356         if (!is_thinint_irq(irq_ptr))
 357                 return;
 358         irq_ptr->dsci = get_indicator();
 359         QDIO_DBF_HEX1(0, setup, &irq_ptr->dsci, sizeof(void *));
 360 }
 361
 362 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 363 {
 364         if (!is_thinint_irq(irq_ptr))
 365                 return;
 366
 367         /* reset adapter interrupt indicators */
 368         put_indicator(irq_ptr->dsci);
 369         set_subchannel_ind(irq_ptr, 1);
 370 }
 371
 372 void __exit tiqdio_unregister_thinints(void)
 373 {
 374         tasklet_disable(&tiqdio_tasklet);
 375
 376         if (tiqdio_alsi) {
 377                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 378                 isc_unregister(QDIO_AIRQ_ISC);
 379         }
 380 }