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 <asm/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 /* list of thin interrupt input queues */
  30 static LIST_HEAD(tiq_list);
  31 DEFINE_MUTEX(tiq_list_lock);
  32
  33 /* adapter local summary indicator */
  34 static unsigned char *tiqdio_alsi;
  35
  36 /* device state change indicators */
  37 struct indicator_t {
  38         u32 ind;        /* u32 because of compare-and-swap performance */
  39         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  40 };
  41 static struct indicator_t *q_indicators;
  42
  43 static int css_qdio_omit_svs;
  44
  45 static inline unsigned long do_clear_global_summary(void)
  46 {
  47         register unsigned long __fn asm("1") = 3;
  48         register unsigned long __tmp asm("2");
  49         register unsigned long __time asm("3");
  50
  51         asm volatile(
  52                 "       .insn   rre,0xb2650000,2,0"
  53                 : "+d" (__fn), "=d" (__tmp), "=d" (__time));
  54         return __time;
  55 }
  56
  57 /* returns addr for the device state change indicator */
  58 static u32 *get_indicator(void)
  59 {
  60         int i;
  61
  62         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  63                 if (!atomic_read(&q_indicators[i].count)) {
  64                         atomic_set(&q_indicators[i].count, 1);
  65                         return &q_indicators[i].ind;
  66                 }
  67
  68         /* use the shared indicator */
  69         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  70         return &q_indicators[TIQDIO_SHARED_IND].ind;
  71 }
  72
  73 static void put_indicator(u32 *addr)
  74 {
  75         int i;
  76
  77         if (!addr)
  78                 return;
  79         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  80                 sizeof(struct indicator_t);
  81         atomic_dec(&q_indicators[i].count);
  82 }
  83
  84 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  85 {
  86         struct qdio_q *q;
  87         int i;
  88
  89         /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
  90         if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
  91                 css_qdio_omit_svs = 1;
  92
  93         mutex_lock(&tiq_list_lock);
  94         for_each_input_queue(irq_ptr, q, i)
  95                 list_add_rcu(&q->entry, &tiq_list);
  96         mutex_unlock(&tiq_list_lock);
  97         xchg(irq_ptr->dsci, 1);
  98 }
  99
 100 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
 101 {
 102         struct qdio_q *q;
 103         int i;
 104
 105         for (i = 0; i < irq_ptr->nr_input_qs; i++) {
 106                 q = irq_ptr->input_qs[i];
 107                 /* if establish triggered an error */
 108                 if (!q || !q->entry.prev || !q->entry.next)
 109                         continue;
 110
 111                 mutex_lock(&tiq_list_lock);
 112                 list_del_rcu(&q->entry);
 113                 mutex_unlock(&tiq_list_lock);
 114                 synchronize_rcu();
 115         }
 116 }
 117
 118 static inline int shared_ind(struct qdio_irq *irq_ptr)
 119 {
 120         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 121 }
 122
 123 /**
 124  * tiqdio_thinint_handler - thin interrupt handler for qdio
 125  * @ind: pointer to adapter local summary indicator
 126  * @drv_data: NULL
 127  */
 128 static void tiqdio_thinint_handler(void *ind, void *drv_data)
 129 {
 130         struct qdio_q *q;
 131
 132         /*
 133          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 134          * avoidance (SVS clears adapter interrupt suppression overwrite)
 135          */
 136         if (!css_qdio_omit_svs)
 137                 do_clear_global_summary();
 138
 139         /*
 140          * reset local summary indicator (tiqdio_alsi) to stop adapter
 141          * interrupts for now
 142          */
 143         xchg((u8 *)ind, 0);
 144
 145         /* protect tiq_list entries, only changed in activate or shutdown */
 146         rcu_read_lock();
 147
 148         /* check for work on all inbound thinint queues */
 149         list_for_each_entry_rcu(q, &tiq_list, entry)
 150                 /* only process queues from changed sets */
 151                 if (*q->irq_ptr->dsci) {
 152                         qperf_inc(q, adapter_int);
 153
 154                         /* only clear it if the indicator is non-shared */
 155                         if (!shared_ind(q->irq_ptr))
 156                                 xchg(q->irq_ptr->dsci, 0);
 157                         /*
 158                          * don't call inbound processing directly since
 159                          * that could starve other thinint queues
 160                          */
 161                         tasklet_schedule(&q->tasklet);
 162                 }
 163
 164         rcu_read_unlock();
 165
 166         /*
 167          * if we used the shared indicator clear it now after all queues
 168          * were processed
 169          */
 170         if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
 171                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 172
 173                 /* prevent racing */
 174                 if (*tiqdio_alsi)
 175                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
 176         }
 177 }
 178
 179 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 180 {
 181         struct scssc_area *scssc_area;
 182         int rc;
 183
 184         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 185         memset(scssc_area, 0, PAGE_SIZE);
 186
 187         if (reset) {
 188                 scssc_area->summary_indicator_addr = 0;
 189                 scssc_area->subchannel_indicator_addr = 0;
 190         } else {
 191                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 192                 scssc_area->subchannel_indicator_addr =
 193                         virt_to_phys(irq_ptr->dsci);
 194         }
 195
 196         scssc_area->request = (struct chsc_header) {
 197                 .length = 0x0fe0,
 198                 .code   = 0x0021,
 199         };
 200         scssc_area->operation_code = 0;
 201         scssc_area->ks = PAGE_DEFAULT_KEY;
 202         scssc_area->kc = PAGE_DEFAULT_KEY;
 203         scssc_area->isc = QDIO_AIRQ_ISC;
 204         scssc_area->schid = irq_ptr->schid;
 205
 206         /* enable the time delay disablement facility */
 207         if (css_general_characteristics.aif_tdd)
 208                 scssc_area->word_with_d_bit = 0x10000000;
 209
 210         rc = chsc(scssc_area);
 211         if (rc)
 212                 return -EIO;
 213
 214         rc = chsc_error_from_response(scssc_area->response.code);
 215         if (rc) {
 216                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 217                           scssc_area->response.code);
 218                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 219                 return rc;
 220         }
 221
 222         DBF_EVENT("setscind");
 223         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 224         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 225         return 0;
 226 }
 227
 228 /* allocate non-shared indicators and shared indicator */
 229 int __init tiqdio_allocate_memory(void)
 230 {
 231         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 232                              GFP_KERNEL);
 233         if (!q_indicators)
 234                 return -ENOMEM;
 235         return 0;
 236 }
 237
 238 void tiqdio_free_memory(void)
 239 {
 240         kfree(q_indicators);
 241 }
 242
 243 int __init tiqdio_register_thinints(void)
 244 {
 245         isc_register(QDIO_AIRQ_ISC);
 246         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 247                                                       NULL, QDIO_AIRQ_ISC);
 248         if (IS_ERR(tiqdio_alsi)) {
 249                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 250                 tiqdio_alsi = NULL;
 251                 isc_unregister(QDIO_AIRQ_ISC);
 252                 return -ENOMEM;
 253         }
 254         return 0;
 255 }
 256
 257 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 258 {
 259         if (!is_thinint_irq(irq_ptr))
 260                 return 0;
 261
 262         /* Check for aif time delay disablement. If installed,
 263          * omit SVS even under LPAR
 264          */
 265         if (css_general_characteristics.aif_tdd)
 266                 css_qdio_omit_svs = 1;
 267         return set_subchannel_ind(irq_ptr, 0);
 268 }
 269
 270 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 271 {
 272         if (!is_thinint_irq(irq_ptr))
 273                 return;
 274         irq_ptr->dsci = get_indicator();
 275         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 276 }
 277
 278 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 279 {
 280         if (!is_thinint_irq(irq_ptr))
 281                 return;
 282
 283         /* reset adapter interrupt indicators */
 284         put_indicator(irq_ptr->dsci);
 285         set_subchannel_ind(irq_ptr, 1);
 286 }
 287
 288 void __exit tiqdio_unregister_thinints(void)
 289 {
 290         WARN_ON(!list_empty(&tiq_list));
 291
 292         if (tiqdio_alsi) {
 293                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 294                 isc_unregister(QDIO_AIRQ_ISC);
 295         }
 296 }