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