release/src-rt-6.x.4708/linux/linux-2.6.36/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 <asm/atomic.h>
  12 #include <asm/debug.h>
  13 #include <asm/qdio.h>
  14 #include <asm/airq.h>
  15 #include <asm/isc.h>
  16
  17 #include "cio.h"
  18 #include "ioasm.h"
  19 #include "qdio.h"
  20 #include "qdio_debug.h"
  21
  22 /*
  23  * Restriction: only 63 iqdio subchannels would have its own indicator,
  24  * after that, subsequent subchannels share one indicator
  25  */
  26 #define TIQDIO_NR_NONSHARED_IND         63
  27 #define TIQDIO_NR_INDICATORS            (TIQDIO_NR_NONSHARED_IND + 1)
  28 #define TIQDIO_SHARED_IND               63
  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 unsigned char *tiqdio_alsi;
  36
  37 /* device state change indicators */
  38 struct indicator_t {
  39         u32 ind;        /* u32 because of compare-and-swap performance */
  40         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  41 };
  42 static struct indicator_t *q_indicators;
  43
  44 static int css_qdio_omit_svs;
  45
  46 static inline unsigned long do_clear_global_summary(void)
  47 {
  48         register unsigned long __fn asm("1") = 3;
  49         register unsigned long __tmp asm("2");
  50         register unsigned long __time asm("3");
  51
  52         asm volatile(
  53                 "       .insn   rre,0xb2650000,2,0"
  54                 : "+d" (__fn), "=d" (__tmp), "=d" (__time));
  55         return __time;
  56 }
  57
  58 /* returns addr for the device state change indicator */
  59 static u32 *get_indicator(void)
  60 {
  61         int i;
  62
  63         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  64                 if (!atomic_read(&q_indicators[i].count)) {
  65                         atomic_set(&q_indicators[i].count, 1);
  66                         return &q_indicators[i].ind;
  67                 }
  68
  69         /* use the shared indicator */
  70         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  71         return &q_indicators[TIQDIO_SHARED_IND].ind;
  72 }
  73
  74 static void put_indicator(u32 *addr)
  75 {
  76         int i;
  77
  78         if (!addr)
  79                 return;
  80         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  81                 sizeof(struct indicator_t);
  82         atomic_dec(&q_indicators[i].count);
  83 }
  84
  85 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  86 {
  87         struct qdio_q *q;
  88         int i;
  89
  90         /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
  91         if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
  92                 css_qdio_omit_svs = 1;
  93
  94         mutex_lock(&tiq_list_lock);
  95         for_each_input_queue(irq_ptr, q, i)
  96                 list_add_rcu(&q->entry, &tiq_list);
  97         mutex_unlock(&tiq_list_lock);
  98         xchg(irq_ptr->dsci, 1 << 7);
  99 }
 100
 101 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
 102 {
 103         struct qdio_q *q;
 104         int i;
 105
 106         for (i = 0; i < irq_ptr->nr_input_qs; i++) {
 107                 q = irq_ptr->input_qs[i];
 108                 /* if establish triggered an error */
 109                 if (!q || !q->entry.prev || !q->entry.next)
 110                         continue;
 111
 112                 mutex_lock(&tiq_list_lock);
 113                 list_del_rcu(&q->entry);
 114                 mutex_unlock(&tiq_list_lock);
 115                 synchronize_rcu();
 116         }
 117 }
 118
 119 static inline int shared_ind(struct qdio_irq *irq_ptr)
 120 {
 121         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 122 }
 123
 124 /**
 125  * tiqdio_thinint_handler - thin interrupt handler for qdio
 126  * @ind: pointer to adapter local summary indicator
 127  * @drv_data: NULL
 128  */
 129 static void tiqdio_thinint_handler(void *ind, void *drv_data)
 130 {
 131         struct qdio_q *q;
 132
 133         /*
 134          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 135          * avoidance (SVS clears adapter interrupt suppression overwrite)
 136          */
 137         if (!css_qdio_omit_svs)
 138                 do_clear_global_summary();
 139
 140         /*
 141          * reset local summary indicator (tiqdio_alsi) to stop adapter
 142          * interrupts for now
 143          */
 144         xchg((u8 *)ind, 0);
 145
 146         /* protect tiq_list entries, only changed in activate or shutdown */
 147         rcu_read_lock();
 148
 149         /* check for work on all inbound thinint queues */
 150         list_for_each_entry_rcu(q, &tiq_list, entry)
 151                 /* only process queues from changed sets */
 152                 if (*q->irq_ptr->dsci) {
 153                         qperf_inc(q, adapter_int);
 154
 155                         /* only clear it if the indicator is non-shared */
 156                         if (!shared_ind(q->irq_ptr))
 157                                 xchg(q->irq_ptr->dsci, 0);
 158                         /*
 159                          * don't call inbound processing directly since
 160                          * that could starve other thinint queues
 161                          */
 162                         tasklet_schedule(&q->tasklet);
 163                 }
 164
 165         rcu_read_unlock();
 166
 167         /*
 168          * if we used the shared indicator clear it now after all queues
 169          * were processed
 170          */
 171         if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
 172                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 173
 174                 /* prevent racing */
 175                 if (*tiqdio_alsi)
 176                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1 << 7);
 177         }
 178 }
 179
 180 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 181 {
 182         struct scssc_area *scssc_area;
 183         int rc;
 184
 185         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 186         memset(scssc_area, 0, PAGE_SIZE);
 187
 188         if (reset) {
 189                 scssc_area->summary_indicator_addr = 0;
 190                 scssc_area->subchannel_indicator_addr = 0;
 191         } else {
 192                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 193                 scssc_area->subchannel_indicator_addr =
 194                         virt_to_phys(irq_ptr->dsci);
 195         }
 196
 197         scssc_area->request = (struct chsc_header) {
 198                 .length = 0x0fe0,
 199                 .code   = 0x0021,
 200         };
 201         scssc_area->operation_code = 0;
 202         scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
 203         scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
 204         scssc_area->isc = QDIO_AIRQ_ISC;
 205         scssc_area->schid = irq_ptr->schid;
 206
 207         /* enable the time delay disablement facility */
 208         if (css_general_characteristics.aif_tdd)
 209                 scssc_area->word_with_d_bit = 0x10000000;
 210
 211         rc = chsc(scssc_area);
 212         if (rc)
 213                 return -EIO;
 214
 215         rc = chsc_error_from_response(scssc_area->response.code);
 216         if (rc) {
 217                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 218                           scssc_area->response.code);
 219                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 220                 return rc;
 221         }
 222
 223         DBF_EVENT("setscind");
 224         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 225         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 226         return 0;
 227 }
 228
 229 /* allocate non-shared indicators and shared indicator */
 230 int __init tiqdio_allocate_memory(void)
 231 {
 232         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 233                              GFP_KERNEL);
 234         if (!q_indicators)
 235                 return -ENOMEM;
 236         return 0;
 237 }
 238
 239 void tiqdio_free_memory(void)
 240 {
 241         kfree(q_indicators);
 242 }
 243
 244 int __init tiqdio_register_thinints(void)
 245 {
 246         isc_register(QDIO_AIRQ_ISC);
 247         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 248                                                       NULL, QDIO_AIRQ_ISC);
 249         if (IS_ERR(tiqdio_alsi)) {
 250                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 251                 tiqdio_alsi = NULL;
 252                 isc_unregister(QDIO_AIRQ_ISC);
 253                 return -ENOMEM;
 254         }
 255         return 0;
 256 }
 257
 258 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 259 {
 260         if (!is_thinint_irq(irq_ptr))
 261                 return 0;
 262
 263         /* Check for aif time delay disablement. If installed,
 264          * omit SVS even under LPAR
 265          */
 266         if (css_general_characteristics.aif_tdd)
 267                 css_qdio_omit_svs = 1;
 268         return set_subchannel_ind(irq_ptr, 0);
 269 }
 270
 271 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 272 {
 273         if (!is_thinint_irq(irq_ptr))
 274                 return;
 275         irq_ptr->dsci = get_indicator();
 276         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 277 }
 278
 279 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 280 {
 281         if (!is_thinint_irq(irq_ptr))
 282                 return;
 283
 284         /* reset adapter interrupt indicators */
 285         put_indicator(irq_ptr->dsci);
 286         set_subchannel_ind(irq_ptr, 1);
 287 }
 288
 289 void __exit tiqdio_unregister_thinints(void)
 290 {
 291         WARN_ON(!list_empty(&tiq_list));
 292
 293         if (tiqdio_alsi) {
 294                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 295                 isc_unregister(QDIO_AIRQ_ISC);
 296         }
 297 }