drivers/s390/cio/qdio_thinint.c

   1 /*
   2  * Copyright IBM Corp. 2000, 2009
   3  * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
   4  *            Cornelia Huck <cornelia.huck@de.ibm.com>
   5  *            Jan Glauber <jang@linux.vnet.ibm.com>
   6  */
   7 #include <linux/io.h>
   8 #include <linux/slab.h>
   9 #include <linux/kernel_stat.h>
  10 #include <linux/atomic.h>
  11 #include <asm/debug.h>
  12 #include <asm/qdio.h>
  13 #include <asm/airq.h>
  14 #include <asm/isc.h>
  15
  16 #include "cio.h"
  17 #include "ioasm.h"
  18 #include "qdio.h"
  19 #include "qdio_debug.h"
  20
  21 /*
  22  * Restriction: only 63 iqdio subchannels would have its own indicator,
  23  * after that, subsequent subchannels share one indicator
  24  */
  25 #define TIQDIO_NR_NONSHARED_IND         63
  26 #define TIQDIO_NR_INDICATORS            (TIQDIO_NR_NONSHARED_IND + 1)
  27 #define TIQDIO_SHARED_IND               63
  28
  29 /* device state change indicators */
  30 struct indicator_t {
  31         u32 ind;        /* u32 because of compare-and-swap performance */
  32         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  33 };
  34
  35 /* list of thin interrupt input queues */
  36 static LIST_HEAD(tiq_list);
  37 static DEFINE_MUTEX(tiq_list_lock);
  38
  39 /* adapter local summary indicator */
  40 static u8 *tiqdio_alsi;
  41
  42 static struct indicator_t *q_indicators;
  43
  44 u64 last_ai_time;
  45
  46 /* returns addr for the device state change indicator */
  47 static u32 *get_indicator(void)
  48 {
  49         int i;
  50
  51         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  52                 if (!atomic_read(&q_indicators[i].count)) {
  53                         atomic_set(&q_indicators[i].count, 1);
  54                         return &q_indicators[i].ind;
  55                 }
  56
  57         /* use the shared indicator */
  58         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  59         return &q_indicators[TIQDIO_SHARED_IND].ind;
  60 }
  61
  62 static void put_indicator(u32 *addr)
  63 {
  64         int i;
  65
  66         if (!addr)
  67                 return;
  68         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  69                 sizeof(struct indicator_t);
  70         atomic_dec(&q_indicators[i].count);
  71 }
  72
  73 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  74 {
  75         mutex_lock(&tiq_list_lock);
  76         list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
  77         mutex_unlock(&tiq_list_lock);
  78         xchg(irq_ptr->dsci, 1 << 7);
  79 }
  80
  81 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
  82 {
  83         struct qdio_q *q;
  84
  85         q = irq_ptr->input_qs[0];
  86         /* if establish triggered an error */
  87         if (!q || !q->entry.prev || !q->entry.next)
  88                 return;
  89
  90         mutex_lock(&tiq_list_lock);
  91         list_del_rcu(&q->entry);
  92         mutex_unlock(&tiq_list_lock);
  93         synchronize_rcu();
  94 }
  95
  96 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
  97 {
  98         return irq_ptr->nr_input_qs > 1;
  99 }
 100
 101 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
 102 {
 103         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 104 }
 105
 106 static inline int shared_ind(struct qdio_irq *irq_ptr)
 107 {
 108         return references_shared_dsci(irq_ptr) ||
 109                 has_multiple_inq_on_dsci(irq_ptr);
 110 }
 111
 112 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
 113 {
 114         if (!is_thinint_irq(irq_ptr))
 115                 return;
 116         if (shared_ind(irq_ptr))
 117                 return;
 118         xchg(irq_ptr->dsci, 0);
 119 }
 120
 121 int test_nonshared_ind(struct qdio_irq *irq_ptr)
 122 {
 123         if (!is_thinint_irq(irq_ptr))
 124                 return 0;
 125         if (shared_ind(irq_ptr))
 126                 return 0;
 127         if (*irq_ptr->dsci)
 128                 return 1;
 129         else
 130                 return 0;
 131 }
 132
 133 static inline u32 clear_shared_ind(void)
 134 {
 135         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
 136                 return 0;
 137         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 138 }
 139
 140 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
 141 {
 142         struct qdio_q *q;
 143         int i;
 144
 145         if (!references_shared_dsci(irq) &&
 146             has_multiple_inq_on_dsci(irq))
 147                 xchg(irq->dsci, 0);
 148
 149         for_each_input_queue(irq, q, i) {
 150                 if (q->u.in.queue_start_poll) {
 151                         /* skip if polling is enabled or already in work */
 152                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
 153                                              &q->u.in.queue_irq_state)) {
 154                                 qperf_inc(q, int_discarded);
 155                                 continue;
 156                         }
 157
 158                         /* avoid dsci clear here, done after processing */
 159                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
 160                                                  q->irq_ptr->int_parm);
 161                 } else {
 162                         if (!shared_ind(q->irq_ptr))
 163                                 xchg(q->irq_ptr->dsci, 0);
 164
 165                         /*
 166                          * Call inbound processing but not directly
 167                          * since that could starve other thinint queues.
 168                          */
 169                         tasklet_schedule(&q->tasklet);
 170                 }
 171         }
 172 }
 173
 174 /**
 175  * tiqdio_thinint_handler - thin interrupt handler for qdio
 176  * @alsi: pointer to adapter local summary indicator
 177  * @data: NULL
 178  */
 179 static void tiqdio_thinint_handler(void *alsi, void *data)
 180 {
 181         u32 si_used = clear_shared_ind();
 182         struct qdio_q *q;
 183
 184         last_ai_time = S390_lowcore.int_clock;
 185         inc_irq_stat(IRQIO_QAI);
 186
 187         /* protect tiq_list entries, only changed in activate or shutdown */
 188         rcu_read_lock();
 189
 190         /* check for work on all inbound thinint queues */
 191         list_for_each_entry_rcu(q, &tiq_list, entry) {
 192                 struct qdio_irq *irq;
 193
 194                 /* only process queues from changed sets */
 195                 irq = q->irq_ptr;
 196                 if (unlikely(references_shared_dsci(irq))) {
 197                         if (!si_used)
 198                                 continue;
 199                 } else if (!*irq->dsci)
 200                         continue;
 201
 202                 tiqdio_call_inq_handlers(irq);
 203
 204                 qperf_inc(q, adapter_int);
 205         }
 206         rcu_read_unlock();
 207 }
 208
 209 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 210 {
 211         struct scssc_area *scssc_area;
 212         int rc;
 213
 214         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 215         memset(scssc_area, 0, PAGE_SIZE);
 216
 217         if (reset) {
 218                 scssc_area->summary_indicator_addr = 0;
 219                 scssc_area->subchannel_indicator_addr = 0;
 220         } else {
 221                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 222                 scssc_area->subchannel_indicator_addr =
 223                         virt_to_phys(irq_ptr->dsci);
 224         }
 225
 226         scssc_area->request = (struct chsc_header) {
 227                 .length = 0x0fe0,
 228                 .code   = 0x0021,
 229         };
 230         scssc_area->operation_code = 0;
 231         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 232         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 233         scssc_area->isc = QDIO_AIRQ_ISC;
 234         scssc_area->schid = irq_ptr->schid;
 235
 236         /* enable the time delay disablement facility */
 237         if (css_general_characteristics.aif_tdd)
 238                 scssc_area->word_with_d_bit = 0x10000000;
 239
 240         rc = chsc(scssc_area);
 241         if (rc)
 242                 return -EIO;
 243
 244         rc = chsc_error_from_response(scssc_area->response.code);
 245         if (rc) {
 246                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 247                           scssc_area->response.code);
 248                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 249                 return rc;
 250         }
 251
 252         DBF_EVENT("setscind");
 253         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 254         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 255         return 0;
 256 }
 257
 258 /* allocate non-shared indicators and shared indicator */
 259 int __init tiqdio_allocate_memory(void)
 260 {
 261         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 262                              GFP_KERNEL);
 263         if (!q_indicators)
 264                 return -ENOMEM;
 265         return 0;
 266 }
 267
 268 void tiqdio_free_memory(void)
 269 {
 270         kfree(q_indicators);
 271 }
 272
 273 int __init tiqdio_register_thinints(void)
 274 {
 275         isc_register(QDIO_AIRQ_ISC);
 276         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 277                                                       NULL, QDIO_AIRQ_ISC);
 278         if (IS_ERR(tiqdio_alsi)) {
 279                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 280                 tiqdio_alsi = NULL;
 281                 isc_unregister(QDIO_AIRQ_ISC);
 282                 return -ENOMEM;
 283         }
 284         return 0;
 285 }
 286
 287 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 288 {
 289         if (!is_thinint_irq(irq_ptr))
 290                 return 0;
 291         return set_subchannel_ind(irq_ptr, 0);
 292 }
 293
 294 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 295 {
 296         if (!is_thinint_irq(irq_ptr))
 297                 return;
 298         irq_ptr->dsci = get_indicator();
 299         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 300 }
 301
 302 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 303 {
 304         if (!is_thinint_irq(irq_ptr))
 305                 return;
 306
 307         /* reset adapter interrupt indicators */
 308         set_subchannel_ind(irq_ptr, 1);
 309         put_indicator(irq_ptr->dsci);
 310 }
 311
 312 void __exit tiqdio_unregister_thinints(void)
 313 {
 314         WARN_ON(!list_empty(&tiq_list));
 315
 316         if (tiqdio_alsi) {
 317                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 318                 isc_unregister(QDIO_AIRQ_ISC);
 319         }
 320 }