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 (i = 0; i < irq_ptr->nr_input_qs; i++) {
 117                 q = irq_ptr->input_qs[i];
 118                 /* if establish triggered an error */
 119                 if (!q || !q->entry.prev || !q->entry.next)
 120                         continue;
 121                 list_del_rcu(&q->entry);
 122                 synchronize_rcu();
 123         }
 124 }
 125
 126 static inline int tiqdio_inbound_q_done(struct qdio_q *q)
 127 {
 128         unsigned char state = 0;
 129
 130         if (!atomic_read(&q->nr_buf_used))
 131                 return 1;
 132
 133         qdio_siga_sync_q(q);
 134         get_buf_state(q, q->first_to_check, &state, 0);
 135
 136         if (state == SLSB_P_INPUT_PRIMED)
 137                 /* more work coming */
 138                 return 0;
 139         return 1;
 140 }
 141
 142 static inline int shared_ind(struct qdio_irq *irq_ptr)
 143 {
 144         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 145 }
 146
 147 static void __tiqdio_inbound_processing(struct qdio_q *q)
 148 {
 149         qdio_perf_stat_inc(&perf_stats.thinint_inbound);
 150         qdio_sync_after_thinint(q);
 151
 152         /*
 153          * Maybe we have work on our outbound queues... at least
 154          * we have to check the PCI capable queues.
 155          */
 156         qdio_check_outbound_after_thinint(q);
 157
 158 again:
 159         if (!qdio_inbound_q_moved(q))
 160                 return;
 161
 162         qdio_kick_inbound_handler(q);
 163
 164         if (!tiqdio_inbound_q_done(q)) {
 165                 qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
 166                 goto again;
 167         }
 168
 169         qdio_stop_polling(q);
 170         /*
 171          * We need to check again to not lose initiative after
 172          * resetting the ACK state.
 173          */
 174         if (!tiqdio_inbound_q_done(q)) {
 175                 qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
 176                 goto again;
 177         }
 178 }
 179
 180 void tiqdio_inbound_processing(unsigned long data)
 181 {
 182         struct qdio_q *q = (struct qdio_q *)data;
 183
 184         __tiqdio_inbound_processing(q);
 185 }
 186
 187 /* check for work on all inbound thinint queues */
 188 static void tiqdio_tasklet_fn(unsigned long data)
 189 {
 190         struct qdio_q *q;
 191
 192         qdio_perf_stat_inc(&perf_stats.tasklet_thinint);
 193 again:
 194
 195         /* protect tiq_list entries, only changed in activate or shutdown */
 196         rcu_read_lock();
 197
 198         list_for_each_entry_rcu(q, &tiq_list, entry)
 199                 /* only process queues from changed sets */
 200                 if (*q->irq_ptr->dsci) {
 201
 202                         /* only clear it if the indicator is non-shared */
 203                         if (!shared_ind(q->irq_ptr))
 204                                 xchg(q->irq_ptr->dsci, 0);
 205                         /*
 206                          * don't call inbound processing directly since
 207                          * that could starve other thinint queues
 208                          */
 209                         tasklet_schedule(&q->tasklet);
 210                 }
 211
 212         rcu_read_unlock();
 213
 214         /*
 215          * if we used the shared indicator clear it now after all queues
 216          * were processed
 217          */
 218         if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
 219                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 220
 221                 /* prevent racing */
 222                 if (*tiqdio_alsi)
 223                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
 224         }
 225
 226         /* check for more work */
 227         if (*tiqdio_alsi) {
 228                 xchg(tiqdio_alsi, 0);
 229                 qdio_perf_stat_inc(&perf_stats.tasklet_thinint_loop);
 230                 goto again;
 231         }
 232 }
 233
 234 /**
 235  * tiqdio_thinint_handler - thin interrupt handler for qdio
 236  * @ind: pointer to adapter local summary indicator
 237  * @drv_data: NULL
 238  */
 239 static void tiqdio_thinint_handler(void *ind, void *drv_data)
 240 {
 241         qdio_perf_stat_inc(&perf_stats.thin_int);
 242
 243         /*
 244          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 245          * avoidance (SVS clears adapter interrupt suppression overwrite)
 246          */
 247         if (!css_qdio_omit_svs)
 248                 do_clear_global_summary();
 249
 250         /*
 251          * reset local summary indicator (tiqdio_alsi) to stop adapter
 252          * interrupts for now, the tasklet will clean all dsci's
 253          */
 254         xchg((u8 *)ind, 0);
 255         tasklet_hi_schedule(&tiqdio_tasklet);
 256 }
 257
 258 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 259 {
 260         struct scssc_area *scssc_area;
 261         int rc;
 262
 263         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 264         memset(scssc_area, 0, PAGE_SIZE);
 265
 266         if (reset) {
 267                 scssc_area->summary_indicator_addr = 0;
 268                 scssc_area->subchannel_indicator_addr = 0;
 269         } else {
 270                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 271                 scssc_area->subchannel_indicator_addr =
 272                         virt_to_phys(irq_ptr->dsci);
 273         }
 274
 275         scssc_area->request = (struct chsc_header) {
 276                 .length = 0x0fe0,
 277                 .code   = 0x0021,
 278         };
 279         scssc_area->operation_code = 0;
 280         scssc_area->ks = PAGE_DEFAULT_KEY;
 281         scssc_area->kc = PAGE_DEFAULT_KEY;
 282         scssc_area->isc = QDIO_AIRQ_ISC;
 283         scssc_area->schid = irq_ptr->schid;
 284
 285         /* enable the time delay disablement facility */
 286         if (css_general_characteristics.aif_tdd)
 287                 scssc_area->word_with_d_bit = 0x10000000;
 288
 289         rc = chsc(scssc_area);
 290         if (rc)
 291                 return -EIO;
 292
 293         rc = chsc_error_from_response(scssc_area->response.code);
 294         if (rc) {
 295                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 296                           scssc_area->response.code);
 297                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 298                 return rc;
 299         }
 300
 301         DBF_EVENT("setscind");
 302         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 303         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 304         return 0;
 305 }
 306
 307 /* allocate non-shared indicators and shared indicator */
 308 int __init tiqdio_allocate_memory(void)
 309 {
 310         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 311                              GFP_KERNEL);
 312         if (!q_indicators)
 313                 return -ENOMEM;
 314         return 0;
 315 }
 316
 317 void tiqdio_free_memory(void)
 318 {
 319         kfree(q_indicators);
 320 }
 321
 322 int __init tiqdio_register_thinints(void)
 323 {
 324         isc_register(QDIO_AIRQ_ISC);
 325         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 326                                                       NULL, QDIO_AIRQ_ISC);
 327         if (IS_ERR(tiqdio_alsi)) {
 328                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 329                 tiqdio_alsi = NULL;
 330                 isc_unregister(QDIO_AIRQ_ISC);
 331                 return -ENOMEM;
 332         }
 333         return 0;
 334 }
 335
 336 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 337 {
 338         if (!is_thinint_irq(irq_ptr))
 339                 return 0;
 340
 341         /* Check for aif time delay disablement. If installed,
 342          * omit SVS even under LPAR
 343          */
 344         if (css_general_characteristics.aif_tdd)
 345                 css_qdio_omit_svs = 1;
 346         return set_subchannel_ind(irq_ptr, 0);
 347 }
 348
 349 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 350 {
 351         if (!is_thinint_irq(irq_ptr))
 352                 return;
 353         irq_ptr->dsci = get_indicator();
 354         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 355 }
 356
 357 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 358 {
 359         if (!is_thinint_irq(irq_ptr))
 360                 return;
 361
 362         /* reset adapter interrupt indicators */
 363         put_indicator(irq_ptr->dsci);
 364         set_subchannel_ind(irq_ptr, 1);
 365 }
 366
 367 void __exit tiqdio_unregister_thinints(void)
 368 {
 369         tasklet_disable(&tiqdio_tasklet);
 370
 371         if (tiqdio_alsi) {
 372                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 373                 isc_unregister(QDIO_AIRQ_ISC);
 374         }
 375 }