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         BUG_ON(irq_ptr->nr_input_qs < 1);
  77         list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
  78         mutex_unlock(&tiq_list_lock);
  79         xchg(irq_ptr->dsci, 1 << 7);
  80 }
  81
  82 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
  83 {
  84         struct qdio_q *q;
  85
  86         BUG_ON(irq_ptr->nr_input_qs < 1);
  87         q = irq_ptr->input_qs[0];
  88         /* if establish triggered an error */
  89         if (!q || !q->entry.prev || !q->entry.next)
  90                 return;
  91
  92         mutex_lock(&tiq_list_lock);
  93         list_del_rcu(&q->entry);
  94         mutex_unlock(&tiq_list_lock);
  95         synchronize_rcu();
  96 }
  97
  98 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
  99 {
 100         return irq_ptr->nr_input_qs > 1;
 101 }
 102
 103 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
 104 {
 105         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 106 }
 107
 108 static inline int shared_ind(struct qdio_irq *irq_ptr)
 109 {
 110         return references_shared_dsci(irq_ptr) ||
 111                 has_multiple_inq_on_dsci(irq_ptr);
 112 }
 113
 114 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
 115 {
 116         if (!is_thinint_irq(irq_ptr))
 117                 return;
 118         if (shared_ind(irq_ptr))
 119                 return;
 120         xchg(irq_ptr->dsci, 0);
 121 }
 122
 123 int test_nonshared_ind(struct qdio_irq *irq_ptr)
 124 {
 125         if (!is_thinint_irq(irq_ptr))
 126                 return 0;
 127         if (shared_ind(irq_ptr))
 128                 return 0;
 129         if (*irq_ptr->dsci)
 130                 return 1;
 131         else
 132                 return 0;
 133 }
 134
 135 static inline u32 clear_shared_ind(void)
 136 {
 137         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
 138                 return 0;
 139         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 140 }
 141
 142 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
 143 {
 144         struct qdio_q *q;
 145         int i;
 146
 147         for_each_input_queue(irq, q, i) {
 148                 if (!references_shared_dsci(irq) &&
 149                     has_multiple_inq_on_dsci(irq))
 150                         xchg(q->irq_ptr->dsci, 0);
 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                         if (!shared_ind(q->irq_ptr))
 165                                 xchg(q->irq_ptr->dsci, 0);
 166
 167                         /*
 168                          * Call inbound processing but not directly
 169                          * since that could starve other thinint queues.
 170                          */
 171                         tasklet_schedule(&q->tasklet);
 172                 }
 173         }
 174 }
 175
 176 /**
 177  * tiqdio_thinint_handler - thin interrupt handler for qdio
 178  * @alsi: pointer to adapter local summary indicator
 179  * @data: NULL
 180  */
 181 static void tiqdio_thinint_handler(void *alsi, void *data)
 182 {
 183         u32 si_used = clear_shared_ind();
 184         struct qdio_q *q;
 185
 186         last_ai_time = S390_lowcore.int_clock;
 187         kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
 188
 189         /* protect tiq_list entries, only changed in activate or shutdown */
 190         rcu_read_lock();
 191
 192         /* check for work on all inbound thinint queues */
 193         list_for_each_entry_rcu(q, &tiq_list, entry) {
 194                 struct qdio_irq *irq;
 195
 196                 /* only process queues from changed sets */
 197                 irq = q->irq_ptr;
 198                 if (unlikely(references_shared_dsci(irq))) {
 199                         if (!si_used)
 200                                 continue;
 201                 } else if (!*irq->dsci)
 202                         continue;
 203
 204                 tiqdio_call_inq_handlers(irq);
 205
 206                 qperf_inc(q, adapter_int);
 207         }
 208         rcu_read_unlock();
 209 }
 210
 211 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 212 {
 213         struct scssc_area *scssc_area;
 214         int rc;
 215
 216         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 217         memset(scssc_area, 0, PAGE_SIZE);
 218
 219         if (reset) {
 220                 scssc_area->summary_indicator_addr = 0;
 221                 scssc_area->subchannel_indicator_addr = 0;
 222         } else {
 223                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 224                 scssc_area->subchannel_indicator_addr =
 225                         virt_to_phys(irq_ptr->dsci);
 226         }
 227
 228         scssc_area->request = (struct chsc_header) {
 229                 .length = 0x0fe0,
 230                 .code   = 0x0021,
 231         };
 232         scssc_area->operation_code = 0;
 233         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 234         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 235         scssc_area->isc = QDIO_AIRQ_ISC;
 236         scssc_area->schid = irq_ptr->schid;
 237
 238         /* enable the time delay disablement facility */
 239         if (css_general_characteristics.aif_tdd)
 240                 scssc_area->word_with_d_bit = 0x10000000;
 241
 242         rc = chsc(scssc_area);
 243         if (rc)
 244                 return -EIO;
 245
 246         rc = chsc_error_from_response(scssc_area->response.code);
 247         if (rc) {
 248                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 249                           scssc_area->response.code);
 250                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 251                 return rc;
 252         }
 253
 254         DBF_EVENT("setscind");
 255         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 256         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 257         return 0;
 258 }
 259
 260 /* allocate non-shared indicators and shared indicator */
 261 int __init tiqdio_allocate_memory(void)
 262 {
 263         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 264                              GFP_KERNEL);
 265         if (!q_indicators)
 266                 return -ENOMEM;
 267         return 0;
 268 }
 269
 270 void tiqdio_free_memory(void)
 271 {
 272         kfree(q_indicators);
 273 }
 274
 275 int __init tiqdio_register_thinints(void)
 276 {
 277         isc_register(QDIO_AIRQ_ISC);
 278         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 279                                                       NULL, QDIO_AIRQ_ISC);
 280         if (IS_ERR(tiqdio_alsi)) {
 281                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 282                 tiqdio_alsi = NULL;
 283                 isc_unregister(QDIO_AIRQ_ISC);
 284                 return -ENOMEM;
 285         }
 286         return 0;
 287 }
 288
 289 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 290 {
 291         if (!is_thinint_irq(irq_ptr))
 292                 return 0;
 293         return set_subchannel_ind(irq_ptr, 0);
 294 }
 295
 296 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 297 {
 298         if (!is_thinint_irq(irq_ptr))
 299                 return;
 300         irq_ptr->dsci = get_indicator();
 301         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 302 }
 303
 304 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 305 {
 306         if (!is_thinint_irq(irq_ptr))
 307                 return;
 308
 309         /* reset adapter interrupt indicators */
 310         set_subchannel_ind(irq_ptr, 1);
 311         put_indicator(irq_ptr->dsci);
 312 }
 313
 314 void __exit tiqdio_unregister_thinints(void)
 315 {
 316         WARN_ON(!list_empty(&tiq_list));
 317
 318         if (tiqdio_alsi) {
 319                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 320                 isc_unregister(QDIO_AIRQ_ISC);
 321         }
 322 }