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