drivers/s390/cio/qdio_thinint.c

   1 /*
   2  * linux/drivers/s390/cio/thinint_qdio.c
   3  *
   4  * Copyright 2000,2009 IBM Corp.
   5  * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
   6  *            Cornelia Huck <cornelia.huck@de.ibm.com>
   7  *            Jan Glauber <jang@linux.vnet.ibm.com>
   8  */
   9 #include <linux/io.h>
  10 #include <linux/slab.h>
  11 #include <asm/atomic.h>
  12 #include <asm/debug.h>
  13 #include <asm/qdio.h>
  14 #include <asm/airq.h>
  15 #include <asm/isc.h>
  16
  17 #include "cio.h"
  18 #include "ioasm.h"
  19 #include "qdio.h"
  20 #include "qdio_debug.h"
  21
  22 /*
  23  * Restriction: only 63 iqdio subchannels would have its own indicator,
  24  * after that, subsequent subchannels share one indicator
  25  */
  26 #define TIQDIO_NR_NONSHARED_IND         63
  27 #define TIQDIO_NR_INDICATORS            (TIQDIO_NR_NONSHARED_IND + 1)
  28
  29 /* list of thin interrupt input queues */
  30 static LIST_HEAD(tiq_list);
  31 DEFINE_MUTEX(tiq_list_lock);
  32
  33 /* adapter local summary indicator */
  34 static u8 *tiqdio_alsi;
  35
  36 struct indicator_t *q_indicators;
  37
  38 static int css_qdio_omit_svs;
  39
  40 static u64 last_ai_time;
  41
  42 static inline unsigned long do_clear_global_summary(void)
  43 {
  44         register unsigned long __fn asm("1") = 3;
  45         register unsigned long __tmp asm("2");
  46         register unsigned long __time asm("3");
  47
  48         asm volatile(
  49                 "       .insn   rre,0xb2650000,2,0"
  50                 : "+d" (__fn), "=d" (__tmp), "=d" (__time));
  51         return __time;
  52 }
  53
  54 /* returns addr for the device state change indicator */
  55 static u32 *get_indicator(void)
  56 {
  57         int i;
  58
  59         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  60                 if (!atomic_read(&q_indicators[i].count)) {
  61                         atomic_set(&q_indicators[i].count, 1);
  62                         return &q_indicators[i].ind;
  63                 }
  64
  65         /* use the shared indicator */
  66         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  67         return &q_indicators[TIQDIO_SHARED_IND].ind;
  68 }
  69
  70 static void put_indicator(u32 *addr)
  71 {
  72         int i;
  73
  74         if (!addr)
  75                 return;
  76         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  77                 sizeof(struct indicator_t);
  78         atomic_dec(&q_indicators[i].count);
  79 }
  80
  81 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  82 {
  83         struct qdio_q *q;
  84         int i;
  85
  86         /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
  87         if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
  88                 css_qdio_omit_svs = 1;
  89
  90         mutex_lock(&tiq_list_lock);
  91         for_each_input_queue(irq_ptr, q, i)
  92                 list_add_rcu(&q->entry, &tiq_list);
  93         mutex_unlock(&tiq_list_lock);
  94         xchg(irq_ptr->dsci, 1 << 7);
  95 }
  96
  97 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
  98 {
  99         struct qdio_q *q;
 100         int i;
 101
 102         for (i = 0; i < irq_ptr->nr_input_qs; i++) {
 103                 q = irq_ptr->input_qs[i];
 104                 /* if establish triggered an error */
 105                 if (!q || !q->entry.prev || !q->entry.next)
 106                         continue;
 107
 108                 mutex_lock(&tiq_list_lock);
 109                 list_del_rcu(&q->entry);
 110                 mutex_unlock(&tiq_list_lock);
 111                 synchronize_rcu();
 112         }
 113 }
 114
 115 static inline int shared_ind_used(void)
 116 {
 117         return atomic_read(&q_indicators[TIQDIO_SHARED_IND].count);
 118 }
 119
 120 /**
 121  * tiqdio_thinint_handler - thin interrupt handler for qdio
 122  * @alsi: pointer to adapter local summary indicator
 123  * @data: NULL
 124  */
 125 static void tiqdio_thinint_handler(void *alsi, void *data)
 126 {
 127         struct qdio_q *q;
 128
 129         last_ai_time = S390_lowcore.int_clock;
 130
 131         /*
 132          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 133          * avoidance (SVS clears adapter interrupt suppression overwrite).
 134          */
 135         if (!css_qdio_omit_svs)
 136                 do_clear_global_summary();
 137
 138         /* reset local summary indicator */
 139         if (shared_ind_used())
 140                 xchg(tiqdio_alsi, 0);
 141
 142         /* protect tiq_list entries, only changed in activate or shutdown */
 143         rcu_read_lock();
 144
 145         /* check for work on all inbound thinint queues */
 146         list_for_each_entry_rcu(q, &tiq_list, entry) {
 147
 148                 /* only process queues from changed sets */
 149                 if (!*q->irq_ptr->dsci)
 150                         continue;
 151
 152                 if (q->u.in.queue_start_poll) {
 153                         /* skip if polling is enabled or already in work */
 154                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
 155                                              &q->u.in.queue_irq_state)) {
 156                                 qperf_inc(q, int_discarded);
 157                                 continue;
 158                         }
 159
 160                         /* avoid dsci clear here, done after processing */
 161                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
 162                                                  q->irq_ptr->int_parm);
 163                 } else {
 164                         /* only clear it if the indicator is non-shared */
 165                         if (!shared_ind(q->irq_ptr))
 166                                 xchg(q->irq_ptr->dsci, 0);
 167                         /*
 168                          * Call inbound processing but not directly
 169                          * since that could starve other thinint queues.
 170                          */
 171                         tasklet_schedule(&q->tasklet);
 172                 }
 173                 qperf_inc(q, adapter_int);
 174         }
 175         rcu_read_unlock();
 176
 177         /*
 178          * If the shared indicator was used clear it now after all queues
 179          * were processed.
 180          */
 181         if (shared_ind_used()) {
 182                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 183
 184                 /* prevent racing */
 185                 if (*tiqdio_alsi)
 186                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1 << 7);
 187         }
 188 }
 189
 190 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 191 {
 192         struct scssc_area *scssc_area;
 193         int rc;
 194
 195         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 196         memset(scssc_area, 0, PAGE_SIZE);
 197
 198         if (reset) {
 199                 scssc_area->summary_indicator_addr = 0;
 200                 scssc_area->subchannel_indicator_addr = 0;
 201         } else {
 202                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 203                 scssc_area->subchannel_indicator_addr =
 204                         virt_to_phys(irq_ptr->dsci);
 205         }
 206
 207         scssc_area->request = (struct chsc_header) {
 208                 .length = 0x0fe0,
 209                 .code   = 0x0021,
 210         };
 211         scssc_area->operation_code = 0;
 212         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 213         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 214         scssc_area->isc = QDIO_AIRQ_ISC;
 215         scssc_area->schid = irq_ptr->schid;
 216
 217         /* enable the time delay disablement facility */
 218         if (css_general_characteristics.aif_tdd)
 219                 scssc_area->word_with_d_bit = 0x10000000;
 220
 221         rc = chsc(scssc_area);
 222         if (rc)
 223                 return -EIO;
 224
 225         rc = chsc_error_from_response(scssc_area->response.code);
 226         if (rc) {
 227                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 228                           scssc_area->response.code);
 229                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 230                 return rc;
 231         }
 232
 233         DBF_EVENT("setscind");
 234         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 235         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 236         return 0;
 237 }
 238
 239 /* allocate non-shared indicators and shared indicator */
 240 int __init tiqdio_allocate_memory(void)
 241 {
 242         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 243                              GFP_KERNEL);
 244         if (!q_indicators)
 245                 return -ENOMEM;
 246         return 0;
 247 }
 248
 249 void tiqdio_free_memory(void)
 250 {
 251         kfree(q_indicators);
 252 }
 253
 254 int __init tiqdio_register_thinints(void)
 255 {
 256         isc_register(QDIO_AIRQ_ISC);
 257         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 258                                                       NULL, QDIO_AIRQ_ISC);
 259         if (IS_ERR(tiqdio_alsi)) {
 260                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 261                 tiqdio_alsi = NULL;
 262                 isc_unregister(QDIO_AIRQ_ISC);
 263                 return -ENOMEM;
 264         }
 265         return 0;
 266 }
 267
 268 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 269 {
 270         if (!is_thinint_irq(irq_ptr))
 271                 return 0;
 272
 273         /* Check for aif time delay disablement. If installed,
 274          * omit SVS even under LPAR
 275          */
 276         if (css_general_characteristics.aif_tdd)
 277                 css_qdio_omit_svs = 1;
 278         return set_subchannel_ind(irq_ptr, 0);
 279 }
 280
 281 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 282 {
 283         if (!is_thinint_irq(irq_ptr))
 284                 return;
 285         irq_ptr->dsci = get_indicator();
 286         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 287 }
 288
 289 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 290 {
 291         if (!is_thinint_irq(irq_ptr))
 292                 return;
 293
 294         /* reset adapter interrupt indicators */
 295         put_indicator(irq_ptr->dsci);
 296         set_subchannel_ind(irq_ptr, 1);
 297 }
 298
 299 void __exit tiqdio_unregister_thinints(void)
 300 {
 301         WARN_ON(!list_empty(&tiq_list));
 302
 303         if (tiqdio_alsi) {
 304                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 305                 isc_unregister(QDIO_AIRQ_ISC);
 306         }
 307 }