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
  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         mutex_lock(&tiq_list_lock);
  71         BUG_ON(irq_ptr->nr_input_qs < 1);
  72         list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
  73         mutex_unlock(&tiq_list_lock);
  74         xchg(irq_ptr->dsci, 1 << 7);
  75 }
  76
  77 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
  78 {
  79         struct qdio_q *q;
  80
  81         BUG_ON(irq_ptr->nr_input_qs < 1);
  82         q = irq_ptr->input_qs[0];
  83         /* if establish triggered an error */
  84         if (!q || !q->entry.prev || !q->entry.next)
  85                 return;
  86
  87         mutex_lock(&tiq_list_lock);
  88         list_del_rcu(&q->entry);
  89         mutex_unlock(&tiq_list_lock);
  90         synchronize_rcu();
  91 }
  92
  93 static inline u32 clear_shared_ind(void)
  94 {
  95         if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
  96                 return 0;
  97         return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
  98 }
  99
 100 static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
 101 {
 102         struct qdio_q *q;
 103         int i;
 104
 105         for_each_input_queue(irq, q, i) {
 106                 if (!references_shared_dsci(irq) &&
 107                     has_multiple_inq_on_dsci(irq))
 108                         xchg(q->irq_ptr->dsci, 0);
 109
 110                 if (q->u.in.queue_start_poll) {
 111                         /* skip if polling is enabled or already in work */
 112                         if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
 113                                              &q->u.in.queue_irq_state)) {
 114                                 qperf_inc(q, int_discarded);
 115                                 continue;
 116                         }
 117
 118                         /* avoid dsci clear here, done after processing */
 119                         q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
 120                                                  q->irq_ptr->int_parm);
 121                 } else {
 122                         if (!shared_ind(q))
 123                                 xchg(q->irq_ptr->dsci, 0);
 124
 125                         /*
 126                          * Call inbound processing but not directly
 127                          * since that could starve other thinint queues.
 128                          */
 129                         tasklet_schedule(&q->tasklet);
 130                 }
 131         }
 132 }
 133
 134 /**
 135  * tiqdio_thinint_handler - thin interrupt handler for qdio
 136  * @alsi: pointer to adapter local summary indicator
 137  * @data: NULL
 138  */
 139 static void tiqdio_thinint_handler(void *alsi, void *data)
 140 {
 141         u32 si_used = clear_shared_ind();
 142         struct qdio_q *q;
 143
 144         last_ai_time = S390_lowcore.int_clock;
 145         kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
 146
 147         /* protect tiq_list entries, only changed in activate or shutdown */
 148         rcu_read_lock();
 149
 150         /* check for work on all inbound thinint queues */
 151         list_for_each_entry_rcu(q, &tiq_list, entry) {
 152                 struct qdio_irq *irq;
 153
 154                 /* only process queues from changed sets */
 155                 irq = q->irq_ptr;
 156                 if (unlikely(references_shared_dsci(irq))) {
 157                         if (!si_used)
 158                                 continue;
 159                 } else if (!*irq->dsci)
 160                         continue;
 161
 162                 tiqdio_call_inq_handlers(irq);
 163
 164                 qperf_inc(q, adapter_int);
 165         }
 166         rcu_read_unlock();
 167 }
 168
 169 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 170 {
 171         struct scssc_area *scssc_area;
 172         int rc;
 173
 174         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 175         memset(scssc_area, 0, PAGE_SIZE);
 176
 177         if (reset) {
 178                 scssc_area->summary_indicator_addr = 0;
 179                 scssc_area->subchannel_indicator_addr = 0;
 180         } else {
 181                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 182                 scssc_area->subchannel_indicator_addr =
 183                         virt_to_phys(irq_ptr->dsci);
 184         }
 185
 186         scssc_area->request = (struct chsc_header) {
 187                 .length = 0x0fe0,
 188                 .code   = 0x0021,
 189         };
 190         scssc_area->operation_code = 0;
 191         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 192         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 193         scssc_area->isc = QDIO_AIRQ_ISC;
 194         scssc_area->schid = irq_ptr->schid;
 195
 196         /* enable the time delay disablement facility */
 197         if (css_general_characteristics.aif_tdd)
 198                 scssc_area->word_with_d_bit = 0x10000000;
 199
 200         rc = chsc(scssc_area);
 201         if (rc)
 202                 return -EIO;
 203
 204         rc = chsc_error_from_response(scssc_area->response.code);
 205         if (rc) {
 206                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 207                           scssc_area->response.code);
 208                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 209                 return rc;
 210         }
 211
 212         DBF_EVENT("setscind");
 213         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 214         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 215         return 0;
 216 }
 217
 218 /* allocate non-shared indicators and shared indicator */
 219 int __init tiqdio_allocate_memory(void)
 220 {
 221         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 222                              GFP_KERNEL);
 223         if (!q_indicators)
 224                 return -ENOMEM;
 225         return 0;
 226 }
 227
 228 void tiqdio_free_memory(void)
 229 {
 230         kfree(q_indicators);
 231 }
 232
 233 int __init tiqdio_register_thinints(void)
 234 {
 235         isc_register(QDIO_AIRQ_ISC);
 236         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 237                                                       NULL, QDIO_AIRQ_ISC);
 238         if (IS_ERR(tiqdio_alsi)) {
 239                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 240                 tiqdio_alsi = NULL;
 241                 isc_unregister(QDIO_AIRQ_ISC);
 242                 return -ENOMEM;
 243         }
 244         return 0;
 245 }
 246
 247 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 248 {
 249         if (!is_thinint_irq(irq_ptr))
 250                 return 0;
 251         return set_subchannel_ind(irq_ptr, 0);
 252 }
 253
 254 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 255 {
 256         if (!is_thinint_irq(irq_ptr))
 257                 return;
 258         irq_ptr->dsci = get_indicator();
 259         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 260 }
 261
 262 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 263 {
 264         if (!is_thinint_irq(irq_ptr))
 265                 return;
 266
 267         /* reset adapter interrupt indicators */
 268         set_subchannel_ind(irq_ptr, 1);
 269         put_indicator(irq_ptr->dsci);
 270 }
 271
 272 void __exit tiqdio_unregister_thinints(void)
 273 {
 274         WARN_ON(!list_empty(&tiq_list));
 275
 276         if (tiqdio_alsi) {
 277                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 278                 isc_unregister(QDIO_AIRQ_ISC);
 279         }
 280 }