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   1 /*
   2  * linux/drivers/s390/cio/thinint_qdio.c
   3  *
   4  * thin interrupt support for qdio
   5  *
   6  * Copyright 2000-2008 IBM Corp.
   7  * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
   8  *            Cornelia Huck <cornelia.huck@de.ibm.com>
   9  *            Jan Glauber <jang@linux.vnet.ibm.com>
  10  */
  11 #include <linux/io.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 #include "qdio_perf.h"
  23
  24 /*
  25  * Restriction: only 63 iqdio subchannels would have its own indicator,
  26  * after that, subsequent subchannels share one indicator
  27  */
  28 #define TIQDIO_NR_NONSHARED_IND         63
  29 #define TIQDIO_NR_INDICATORS            (TIQDIO_NR_NONSHARED_IND + 1)
  30 #define TIQDIO_SHARED_IND               63
  31
  32 /* list of thin interrupt input queues */
  33 static LIST_HEAD(tiq_list);
  34 DEFINE_MUTEX(tiq_list_lock);
  35
  36 /* adapter local summary indicator */
  37 static unsigned char *tiqdio_alsi;
  38
  39 /* device state change indicators */
  40 struct indicator_t {
  41         u32 ind;        /* u32 because of compare-and-swap performance */
  42         atomic_t count; /* use count, 0 or 1 for non-shared indicators */
  43 };
  44 static struct indicator_t *q_indicators;
  45
  46 static int css_qdio_omit_svs;
  47
  48 static inline unsigned long do_clear_global_summary(void)
  49 {
  50         register unsigned long __fn asm("1") = 3;
  51         register unsigned long __tmp asm("2");
  52         register unsigned long __time asm("3");
  53
  54         asm volatile(
  55                 "       .insn   rre,0xb2650000,2,0"
  56                 : "+d" (__fn), "=d" (__tmp), "=d" (__time));
  57         return __time;
  58 }
  59
  60 /* returns addr for the device state change indicator */
  61 static u32 *get_indicator(void)
  62 {
  63         int i;
  64
  65         for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
  66                 if (!atomic_read(&q_indicators[i].count)) {
  67                         atomic_set(&q_indicators[i].count, 1);
  68                         return &q_indicators[i].ind;
  69                 }
  70
  71         /* use the shared indicator */
  72         atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
  73         return &q_indicators[TIQDIO_SHARED_IND].ind;
  74 }
  75
  76 static void put_indicator(u32 *addr)
  77 {
  78         int i;
  79
  80         if (!addr)
  81                 return;
  82         i = ((unsigned long)addr - (unsigned long)q_indicators) /
  83                 sizeof(struct indicator_t);
  84         atomic_dec(&q_indicators[i].count);
  85 }
  86
  87 void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
  88 {
  89         struct qdio_q *q;
  90         int i;
  91
  92         /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
  93         if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
  94                 css_qdio_omit_svs = 1;
  95
  96         mutex_lock(&tiq_list_lock);
  97         for_each_input_queue(irq_ptr, q, i)
  98                 list_add_rcu(&q->entry, &tiq_list);
  99         mutex_unlock(&tiq_list_lock);
 100         xchg(irq_ptr->dsci, 1);
 101 }
 102
 103 void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
 104 {
 105         struct qdio_q *q;
 106         int i;
 107
 108         for (i = 0; i < irq_ptr->nr_input_qs; i++) {
 109                 q = irq_ptr->input_qs[i];
 110                 /* if establish triggered an error */
 111                 if (!q || !q->entry.prev || !q->entry.next)
 112                         continue;
 113
 114                 mutex_lock(&tiq_list_lock);
 115                 list_del_rcu(&q->entry);
 116                 mutex_unlock(&tiq_list_lock);
 117                 synchronize_rcu();
 118         }
 119 }
 120
 121 static inline int shared_ind(struct qdio_irq *irq_ptr)
 122 {
 123         return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
 124 }
 125
 126 /**
 127  * tiqdio_thinint_handler - thin interrupt handler for qdio
 128  * @ind: pointer to adapter local summary indicator
 129  * @drv_data: NULL
 130  */
 131 static void tiqdio_thinint_handler(void *ind, void *drv_data)
 132 {
 133         struct qdio_q *q;
 134
 135         qdio_perf_stat_inc(&perf_stats.thin_int);
 136
 137         /*
 138          * SVS only when needed: issue SVS to benefit from iqdio interrupt
 139          * avoidance (SVS clears adapter interrupt suppression overwrite)
 140          */
 141         if (!css_qdio_omit_svs)
 142                 do_clear_global_summary();
 143
 144         /*
 145          * reset local summary indicator (tiqdio_alsi) to stop adapter
 146          * interrupts for now
 147          */
 148         xchg((u8 *)ind, 0);
 149
 150         /* protect tiq_list entries, only changed in activate or shutdown */
 151         rcu_read_lock();
 152
 153         /* check for work on all inbound thinint queues */
 154         list_for_each_entry_rcu(q, &tiq_list, entry)
 155                 /* only process queues from changed sets */
 156                 if (*q->irq_ptr->dsci) {
 157
 158                         /* only clear it if the indicator is non-shared */
 159                         if (!shared_ind(q->irq_ptr))
 160                                 xchg(q->irq_ptr->dsci, 0);
 161                         /*
 162                          * don't call inbound processing directly since
 163                          * that could starve other thinint queues
 164                          */
 165                         tasklet_schedule(&q->tasklet);
 166                 }
 167
 168         rcu_read_unlock();
 169
 170         /*
 171          * if we used the shared indicator clear it now after all queues
 172          * were processed
 173          */
 174         if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
 175                 xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
 176
 177                 /* prevent racing */
 178                 if (*tiqdio_alsi)
 179                         xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
 180         }
 181 }
 182
 183 static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
 184 {
 185         struct scssc_area *scssc_area;
 186         int rc;
 187
 188         scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
 189         memset(scssc_area, 0, PAGE_SIZE);
 190
 191         if (reset) {
 192                 scssc_area->summary_indicator_addr = 0;
 193                 scssc_area->subchannel_indicator_addr = 0;
 194         } else {
 195                 scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
 196                 scssc_area->subchannel_indicator_addr =
 197                         virt_to_phys(irq_ptr->dsci);
 198         }
 199
 200         scssc_area->request = (struct chsc_header) {
 201                 .length = 0x0fe0,
 202                 .code   = 0x0021,
 203         };
 204         scssc_area->operation_code = 0;
 205         scssc_area->ks = PAGE_DEFAULT_KEY;
 206         scssc_area->kc = PAGE_DEFAULT_KEY;
 207         scssc_area->isc = QDIO_AIRQ_ISC;
 208         scssc_area->schid = irq_ptr->schid;
 209
 210         /* enable the time delay disablement facility */
 211         if (css_general_characteristics.aif_tdd)
 212                 scssc_area->word_with_d_bit = 0x10000000;
 213
 214         rc = chsc(scssc_area);
 215         if (rc)
 216                 return -EIO;
 217
 218         rc = chsc_error_from_response(scssc_area->response.code);
 219         if (rc) {
 220                 DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
 221                           scssc_area->response.code);
 222                 DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
 223                 return rc;
 224         }
 225
 226         DBF_EVENT("setscind");
 227         DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
 228         DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
 229         return 0;
 230 }
 231
 232 /* allocate non-shared indicators and shared indicator */
 233 int __init tiqdio_allocate_memory(void)
 234 {
 235         q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
 236                              GFP_KERNEL);
 237         if (!q_indicators)
 238                 return -ENOMEM;
 239         return 0;
 240 }
 241
 242 void tiqdio_free_memory(void)
 243 {
 244         kfree(q_indicators);
 245 }
 246
 247 int __init tiqdio_register_thinints(void)
 248 {
 249         isc_register(QDIO_AIRQ_ISC);
 250         tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
 251                                                       NULL, QDIO_AIRQ_ISC);
 252         if (IS_ERR(tiqdio_alsi)) {
 253                 DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
 254                 tiqdio_alsi = NULL;
 255                 isc_unregister(QDIO_AIRQ_ISC);
 256                 return -ENOMEM;
 257         }
 258         return 0;
 259 }
 260
 261 int qdio_establish_thinint(struct qdio_irq *irq_ptr)
 262 {
 263         if (!is_thinint_irq(irq_ptr))
 264                 return 0;
 265
 266         /* Check for aif time delay disablement. If installed,
 267          * omit SVS even under LPAR
 268          */
 269         if (css_general_characteristics.aif_tdd)
 270                 css_qdio_omit_svs = 1;
 271         return set_subchannel_ind(irq_ptr, 0);
 272 }
 273
 274 void qdio_setup_thinint(struct qdio_irq *irq_ptr)
 275 {
 276         if (!is_thinint_irq(irq_ptr))
 277                 return;
 278         irq_ptr->dsci = get_indicator();
 279         DBF_HEX(&irq_ptr->dsci, sizeof(void *));
 280 }
 281
 282 void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
 283 {
 284         if (!is_thinint_irq(irq_ptr))
 285                 return;
 286
 287         /* reset adapter interrupt indicators */
 288         put_indicator(irq_ptr->dsci);
 289         set_subchannel_ind(irq_ptr, 1);
 290 }
 291
 292 void __exit tiqdio_unregister_thinints(void)
 293 {
 294         WARN_ON(!list_empty(&tiq_list));
 295
 296         if (tiqdio_alsi) {
 297                 s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
 298                 isc_unregister(QDIO_AIRQ_ISC);
 299         }
 300 }