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 clear_shared_ind(void)
  99 {
 100         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
 101                 return 0;
 102         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 103 }
 104
 105 /**
 106  * tiqdio_thinint_handler - thin interrupt handler for qdio
 107  * @alsi: pointer to adapter local summary indicator
 108  * @data: NULL
 109  */
 110 static void tiqdio_thinint_handler(void *alsi, void *data)
 111 {
 112         u32 si_used = clear_shared_ind();
 113         struct qdio_q *q;
 114
 115         last_ai_time = S390_lowcore.int_clock;
 116         kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
 117
 118         /* protect tiq_list entries, only changed in activate or shutdown */
 119         rcu_read_lock();
 120
 121         /* check for work on all inbound thinint queues */
 122         list_for_each_entry_rcu(q, &tiq_list, entry) {
 123
 124                 /* only process queues from changed sets */
 125                 if (unlikely(shared_ind(q->irq_ptr->dsci))) {
 126                         if (!si_used)
 127                                 continue;
 128                 } else if (!*q->irq_ptr->dsci)
 129                         continue;
 130
 131                 if (q->u.in.queue_start_poll) {
 132                         /* skip if polling is enabled or already in work */
 133                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
 134                                              &q->u.in.queue_irq_state)) {
 135                                 qperf_inc(q, int_discarded);
 136                                 continue;
 137                         }
 138
 139                         /* avoid dsci clear here, done after processing */
 140                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
 141                                                  q->irq_ptr->int_parm);
 142                 } else {
 143                         /* only clear it if the indicator is non-shared */
 144                         if (!shared_ind(q->irq_ptr->dsci))
 145                                 xchg(q->irq_ptr->dsci, 0);
 146                         /*
 147                          * Call inbound processing but not directly
 148                          * since that could starve other thinint queues.
 149                          */
 150                         tasklet_schedule(&q->tasklet);
 151                 }
 152                 qperf_inc(q, adapter_int);
 153         }
 154         rcu_read_unlock();
 155 }
 156
 157 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 158 {
 159         struct scssc_area *scssc_area;
 160         int rc;
 161
 162         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 163         memset(scssc_area, 0, PAGE_SIZE);
 164
 165         if (reset) {
 166                 scssc_area->summary_indicator_addr = 0;
 167                 scssc_area->subchannel_indicator_addr = 0;
 168         } else {
 169                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 170                 scssc_area->subchannel_indicator_addr =
 171                         virt_to_phys(irq_ptr->dsci);
 172         }
 173
 174         scssc_area->request = (struct chsc_header) {
 175                 .length = 0x0fe0,
 176                 .code   = 0x0021,
 177         };
 178         scssc_area->operation_code = 0;
 179         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 180         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 181         scssc_area->isc = QDIO_AIRQ_ISC;
 182         scssc_area->schid = irq_ptr->schid;
 183
 184         /* enable the time delay disablement facility */
 185         if (css_general_characteristics.aif_tdd)
 186                 scssc_area->word_with_d_bit = 0x10000000;
 187
 188         rc = chsc(scssc_area);
 189         if (rc)
 190                 return -EIO;
 191
 192         rc = chsc_error_from_response(scssc_area->response.code);
 193         if (rc) {
 194                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 195                           scssc_area->response.code);
 196                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 197                 return rc;
 198         }
 199
 200         DBF_EVENT("setscind");
 201         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 202         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 203         return 0;
 204 }
 205
 206 /* allocate non-shared indicators and shared indicator */
 207 int __init tiqdio_allocate_memory(void)
 208 {
 209         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 210                              GFP_KERNEL);
 211         if (!q_indicators)
 212                 return -ENOMEM;
 213         return 0;
 214 }
 215
 216 void tiqdio_free_memory(void)
 217 {
 218         kfree(q_indicators);
 219 }
 220
 221 int __init tiqdio_register_thinints(void)
 222 {
 223         isc_register(QDIO_AIRQ_ISC);
 224         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 225                                                       NULL, QDIO_AIRQ_ISC);
 226         if (IS_ERR(tiqdio_alsi)) {
 227                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 228                 tiqdio_alsi = NULL;
 229                 isc_unregister(QDIO_AIRQ_ISC);
 230                 return -ENOMEM;
 231         }
 232         return 0;
 233 }
 234
 235 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 236 {
 237         if (!is_thinint_irq(irq_ptr))
 238                 return 0;
 239         return set_subchannel_ind(irq_ptr, 0);
 240 }
 241
 242 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 243 {
 244         if (!is_thinint_irq(irq_ptr))
 245                 return;
 246         irq_ptr->dsci = get_indicator();
 247         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 248 }
 249
 250 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 251 {
 252         if (!is_thinint_irq(irq_ptr))
 253                 return;
 254
 255         /* reset adapter interrupt indicators */
 256         set_subchannel_ind(irq_ptr, 1);
 257         put_indicator(irq_ptr->dsci);
 258 }
 259
 260 void __exit tiqdio_unregister_thinints(void)
 261 {
 262         WARN_ON(!list_empty(&tiq_list));
 263
 264         if (tiqdio_alsi) {
 265                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 266                 isc_unregister(QDIO_AIRQ_ISC);
 267         }
 268 }