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 <linux/kernel_stat.h>
  12 #include <linux/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
  23 /*
  24  * Restriction: only 63 iqdio subchannels would have its own indicator,
  25  * after that, subsequent subchannels share one indicator
  26  */
  27 #define TIQDIO_NR_NONSHARED_IND         63
  28 #define TIQDIO_NR_INDICATORS            (TIQDIO_NR_NONSHARED_IND + 1)
  29 #define TIQDIO_SHARED_IND               63
  30
  31 /* device state change indicators */
  32 struct indicator_t {
  33         u32 ind;        /* u32 because of compare-and-swap performance */
  34         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  35 };
  36
  37 /* list of thin interrupt input queues */
  38 static LIST_HEAD(tiq_list);
  39 static DEFINE_MUTEX(tiq_list_lock);
  40
  41 /* adapter local summary indicator */
  42 static u8 *tiqdio_alsi;
  43
  44 static struct indicator_t *q_indicators;
  45
  46 u64 last_ai_time;
  47
  48 /* returns addr for the device state change indicator */
  49 static u32 *get_indicator(void)
  50 {
  51         int i;
  52
  53         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  54                 if (!atomic_read(&q_indicators[i].count)) {
  55                         atomic_set(&q_indicators[i].count, 1);
  56                         return &q_indicators[i].ind;
  57                 }
  58
  59         /* use the shared indicator */
  60         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  61         return &q_indicators[TIQDIO_SHARED_IND].ind;
  62 }
  63
  64 static void put_indicator(u32 *addr)
  65 {
  66         int i;
  67
  68         if (!addr)
  69                 return;
  70         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  71                 sizeof(struct indicator_t);
  72         atomic_dec(&q_indicators[i].count);
  73 }
  74
  75 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  76 {
  77         mutex_lock(&tiq_list_lock);
  78         BUG_ON(irq_ptr->nr_input_qs < 1);
  79         list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
  80         mutex_unlock(&tiq_list_lock);
  81         xchg(irq_ptr->dsci, 1 << 7);
  82 }
  83
  84 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
  85 {
  86         struct qdio_q *q;
  87
  88         BUG_ON(irq_ptr->nr_input_qs < 1);
  89         q = irq_ptr->input_qs[0];
  90         /* if establish triggered an error */
  91         if (!q || !q->entry.prev || !q->entry.next)
  92                 return;
  93
  94         mutex_lock(&tiq_list_lock);
  95         list_del_rcu(&q->entry);
  96         mutex_unlock(&tiq_list_lock);
  97         synchronize_rcu();
  98 }
  99
 100 static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
 101 {
 102         return irq_ptr->nr_input_qs > 1;
 103 }
 104
 105 static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
 106 {
 107         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 108 }
 109
 110 static inline int shared_ind(struct qdio_irq *irq_ptr)
 111 {
 112         return references_shared_dsci(irq_ptr) ||
 113                 has_multiple_inq_on_dsci(irq_ptr);
 114 }
 115
 116 void clear_nonshared_ind(struct qdio_irq *irq_ptr)
 117 {
 118         if (!is_thinint_irq(irq_ptr))
 119                 return;
 120         if (shared_ind(irq_ptr))
 121                 return;
 122         xchg(irq_ptr->dsci, 0);
 123 }
 124
 125 int test_nonshared_ind(struct qdio_irq *irq_ptr)
 126 {
 127         if (!is_thinint_irq(irq_ptr))
 128                 return 0;
 129         if (shared_ind(irq_ptr))
 130                 return 0;
 131         if (*irq_ptr->dsci)
 132                 return 1;
 133         else
 134                 return 0;
 135 }
 136
 137 static inline u32 clear_shared_ind(void)
 138 {
 139         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
 140                 return 0;
 141         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 142 }
 143
 144 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
 145 {
 146         struct qdio_q *q;
 147         int i;
 148
 149         for_each_input_queue(irq, q, i) {
 150                 if (!references_shared_dsci(irq) &&
 151                     has_multiple_inq_on_dsci(irq))
 152                         xchg(q->irq_ptr->dsci, 0);
 153
 154                 if (q->u.in.queue_start_poll) {
 155                         /* skip if polling is enabled or already in work */
 156                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
 157                                              &q->u.in.queue_irq_state)) {
 158                                 qperf_inc(q, int_discarded);
 159                                 continue;
 160                         }
 161
 162                         /* avoid dsci clear here, done after processing */
 163                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
 164                                                  q->irq_ptr->int_parm);
 165                 } else {
 166                         if (!shared_ind(q->irq_ptr))
 167                                 xchg(q->irq_ptr->dsci, 0);
 168
 169                         /*
 170                          * Call inbound processing but not directly
 171                          * since that could starve other thinint queues.
 172                          */
 173                         tasklet_schedule(&q->tasklet);
 174                 }
 175         }
 176 }
 177
 178 /**
 179  * tiqdio_thinint_handler - thin interrupt handler for qdio
 180  * @alsi: pointer to adapter local summary indicator
 181  * @data: NULL
 182  */
 183 static void tiqdio_thinint_handler(void *alsi, void *data)
 184 {
 185         u32 si_used = clear_shared_ind();
 186         struct qdio_q *q;
 187
 188         last_ai_time = S390_lowcore.int_clock;
 189         kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
 190
 191         /* protect tiq_list entries, only changed in activate or shutdown */
 192         rcu_read_lock();
 193
 194         /* check for work on all inbound thinint queues */
 195         list_for_each_entry_rcu(q, &tiq_list, entry) {
 196                 struct qdio_irq *irq;
 197
 198                 /* only process queues from changed sets */
 199                 irq = q->irq_ptr;
 200                 if (unlikely(references_shared_dsci(irq))) {
 201                         if (!si_used)
 202                                 continue;
 203                 } else if (!*irq->dsci)
 204                         continue;
 205
 206                 tiqdio_call_inq_handlers(irq);
 207
 208                 qperf_inc(q, adapter_int);
 209         }
 210         rcu_read_unlock();
 211 }
 212
 213 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 214 {
 215         struct scssc_area *scssc_area;
 216         int rc;
 217
 218         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 219         memset(scssc_area, 0, PAGE_SIZE);
 220
 221         if (reset) {
 222                 scssc_area->summary_indicator_addr = 0;
 223                 scssc_area->subchannel_indicator_addr = 0;
 224         } else {
 225                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 226                 scssc_area->subchannel_indicator_addr =
 227                         virt_to_phys(irq_ptr->dsci);
 228         }
 229
 230         scssc_area->request = (struct chsc_header) {
 231                 .length = 0x0fe0,
 232                 .code   = 0x0021,
 233         };
 234         scssc_area->operation_code = 0;
 235         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 236         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 237         scssc_area->isc = QDIO_AIRQ_ISC;
 238         scssc_area->schid = irq_ptr->schid;
 239
 240         /* enable the time delay disablement facility */
 241         if (css_general_characteristics.aif_tdd)
 242                 scssc_area->word_with_d_bit = 0x10000000;
 243
 244         rc = chsc(scssc_area);
 245         if (rc)
 246                 return -EIO;
 247
 248         rc = chsc_error_from_response(scssc_area->response.code);
 249         if (rc) {
 250                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 251                           scssc_area->response.code);
 252                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 253                 return rc;
 254         }
 255
 256         DBF_EVENT("setscind");
 257         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 258         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 259         return 0;
 260 }
 261
 262 /* allocate non-shared indicators and shared indicator */
 263 int __init tiqdio_allocate_memory(void)
 264 {
 265         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 266                              GFP_KERNEL);
 267         if (!q_indicators)
 268                 return -ENOMEM;
 269         return 0;
 270 }
 271
 272 void tiqdio_free_memory(void)
 273 {
 274         kfree(q_indicators);
 275 }
 276
 277 int __init tiqdio_register_thinints(void)
 278 {
 279         isc_register(QDIO_AIRQ_ISC);
 280         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 281                                                       NULL, QDIO_AIRQ_ISC);
 282         if (IS_ERR(tiqdio_alsi)) {
 283                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 284                 tiqdio_alsi = NULL;
 285                 isc_unregister(QDIO_AIRQ_ISC);
 286                 return -ENOMEM;
 287         }
 288         return 0;
 289 }
 290
 291 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 292 {
 293         if (!is_thinint_irq(irq_ptr))
 294                 return 0;
 295         return set_subchannel_ind(irq_ptr, 0);
 296 }
 297
 298 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 299 {
 300         if (!is_thinint_irq(irq_ptr))
 301                 return;
 302         irq_ptr->dsci = get_indicator();
 303         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 304 }
 305
 306 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 307 {
 308         if (!is_thinint_irq(irq_ptr))
 309                 return;
 310
 311         /* reset adapter interrupt indicators */
 312         set_subchannel_ind(irq_ptr, 1);
 313         put_indicator(irq_ptr->dsci);
 314 }
 315
 316 void __exit tiqdio_unregister_thinints(void)
 317 {
 318         WARN_ON(!list_empty(&tiq_list));
 319
 320         if (tiqdio_alsi) {
 321                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 322                 isc_unregister(QDIO_AIRQ_ISC);
 323         }
 324 }