drivers/s390/cio/airq.c

   1 /*
   2  *    Support for adapter interruptions
   3  *
   4  *    Copyright IBM Corp. 1999, 2007
   5  *    Author(s): Ingo Adlung <adlung@de.ibm.com>
   6  *               Cornelia Huck <cornelia.huck@de.ibm.com>
   7  *               Arnd Bergmann <arndb@de.ibm.com>
   8  *               Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/irq.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/rculist.h>
  17 #include <linux/slab.h>
  18
  19 #include <asm/airq.h>
  20 #include <asm/isc.h>
  21
  22 #include "cio.h"
  23 #include "cio_debug.h"
  24 #include "ioasm.h"
  25
  26 static DEFINE_SPINLOCK(airq_lists_lock);
  27 static struct hlist_head airq_lists[MAX_ISC+1];
  28
  29 /**
  30  * register_adapter_interrupt() - register adapter interrupt handler
  31  * @airq: pointer to adapter interrupt descriptor
  32  *
  33  * Returns 0 on success, or -EINVAL.
  34  */
  35 int register_adapter_interrupt(struct airq_struct *airq)
  36 {
  37         char dbf_txt[32];
  38
  39         if (!airq->handler || airq->isc > MAX_ISC)
  40                 return -EINVAL;
  41         if (!airq->lsi_ptr) {
  42                 airq->lsi_ptr = kzalloc(1, GFP_KERNEL);
  43                 if (!airq->lsi_ptr)
  44                         return -ENOMEM;
  45                 airq->flags |= AIRQ_PTR_ALLOCATED;
  46         }
  47         if (!airq->lsi_mask)
  48                 airq->lsi_mask = 0xff;
  49         snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%p", airq);
  50         CIO_TRACE_EVENT(4, dbf_txt);
  51         isc_register(airq->isc);
  52         spin_lock(&airq_lists_lock);
  53         hlist_add_head_rcu(&airq->list, &airq_lists[airq->isc]);
  54         spin_unlock(&airq_lists_lock);
  55         return 0;
  56 }
  57 EXPORT_SYMBOL(register_adapter_interrupt);
  58
  59 /**
  60  * unregister_adapter_interrupt - unregister adapter interrupt handler
  61  * @airq: pointer to adapter interrupt descriptor
  62  */
  63 void unregister_adapter_interrupt(struct airq_struct *airq)
  64 {
  65         char dbf_txt[32];
  66
  67         if (hlist_unhashed(&airq->list))
  68                 return;
  69         snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%p", airq);
  70         CIO_TRACE_EVENT(4, dbf_txt);
  71         spin_lock(&airq_lists_lock);
  72         hlist_del_rcu(&airq->list);
  73         spin_unlock(&airq_lists_lock);
  74         synchronize_rcu();
  75         isc_unregister(airq->isc);
  76         if (airq->flags & AIRQ_PTR_ALLOCATED) {
  77                 kfree(airq->lsi_ptr);
  78                 airq->lsi_ptr = NULL;
  79                 airq->flags &= ~AIRQ_PTR_ALLOCATED;
  80         }
  81 }
  82 EXPORT_SYMBOL(unregister_adapter_interrupt);
  83
  84 static irqreturn_t do_airq_interrupt(int irq, void *dummy)
  85 {
  86         struct tpi_info *tpi_info;
  87         struct airq_struct *airq;
  88         struct hlist_head *head;
  89
  90         set_cpu_flag(CIF_NOHZ_DELAY);
  91         tpi_info = (struct tpi_info *) &get_irq_regs()->int_code;
  92         head = &airq_lists[tpi_info->isc];
  93         rcu_read_lock();
  94         hlist_for_each_entry_rcu(airq, head, list)
  95                 if ((*airq->lsi_ptr & airq->lsi_mask) != 0)
  96                         airq->handler(airq);
  97         rcu_read_unlock();
  98
  99         return IRQ_HANDLED;
 100 }
 101
 102 static struct irqaction airq_interrupt = {
 103         .name    = "AIO",
 104         .handler = do_airq_interrupt,
 105 };
 106
 107 void __init init_airq_interrupts(void)
 108 {
 109         irq_set_chip_and_handler(THIN_INTERRUPT,
 110                                  &dummy_irq_chip, handle_percpu_irq);
 111         setup_irq(THIN_INTERRUPT, &airq_interrupt);
 112 }
 113
 114 /**
 115  * airq_iv_create - create an interrupt vector
 116  * @bits: number of bits in the interrupt vector
 117  * @flags: allocation flags
 118  *
 119  * Returns a pointer to an interrupt vector structure
 120  */
 121 struct airq_iv *airq_iv_create(unsigned long bits, unsigned long flags)
 122 {
 123         struct airq_iv *iv;
 124         unsigned long size;
 125
 126         iv = kzalloc(sizeof(*iv), GFP_KERNEL);
 127         if (!iv)
 128                 goto out;
 129         iv->bits = bits;
 130         size = BITS_TO_LONGS(bits) * sizeof(unsigned long);
 131         iv->vector = kzalloc(size, GFP_KERNEL);
 132         if (!iv->vector)
 133                 goto out_free;
 134         if (flags & AIRQ_IV_ALLOC) {
 135                 iv->avail = kmalloc(size, GFP_KERNEL);
 136                 if (!iv->avail)
 137                         goto out_free;
 138                 memset(iv->avail, 0xff, size);
 139                 iv->end = 0;
 140         } else
 141                 iv->end = bits;
 142         if (flags & AIRQ_IV_BITLOCK) {
 143                 iv->bitlock = kzalloc(size, GFP_KERNEL);
 144                 if (!iv->bitlock)
 145                         goto out_free;
 146         }
 147         if (flags & AIRQ_IV_PTR) {
 148                 size = bits * sizeof(unsigned long);
 149                 iv->ptr = kzalloc(size, GFP_KERNEL);
 150                 if (!iv->ptr)
 151                         goto out_free;
 152         }
 153         if (flags & AIRQ_IV_DATA) {
 154                 size = bits * sizeof(unsigned int);
 155                 iv->data = kzalloc(size, GFP_KERNEL);
 156                 if (!iv->data)
 157                         goto out_free;
 158         }
 159         spin_lock_init(&iv->lock);
 160         return iv;
 161
 162 out_free:
 163         kfree(iv->ptr);
 164         kfree(iv->bitlock);
 165         kfree(iv->avail);
 166         kfree(iv->vector);
 167         kfree(iv);
 168 out:
 169         return NULL;
 170 }
 171 EXPORT_SYMBOL(airq_iv_create);
 172
 173 /**
 174  * airq_iv_release - release an interrupt vector
 175  * @iv: pointer to interrupt vector structure
 176  */
 177 void airq_iv_release(struct airq_iv *iv)
 178 {
 179         kfree(iv->data);
 180         kfree(iv->ptr);
 181         kfree(iv->bitlock);
 182         kfree(iv->vector);
 183         kfree(iv->avail);
 184         kfree(iv);
 185 }
 186 EXPORT_SYMBOL(airq_iv_release);
 187
 188 /**
 189  * airq_iv_alloc - allocate irq bits from an interrupt vector
 190  * @iv: pointer to an interrupt vector structure
 191  * @num: number of consecutive irq bits to allocate
 192  *
 193  * Returns the bit number of the first irq in the allocated block of irqs,
 194  * or -1UL if no bit is available or the AIRQ_IV_ALLOC flag has not been
 195  * specified
 196  */
 197 unsigned long airq_iv_alloc(struct airq_iv *iv, unsigned long num)
 198 {
 199         unsigned long bit, i, flags;
 200
 201         if (!iv->avail || num == 0)
 202                 return -1UL;
 203         spin_lock_irqsave(&iv->lock, flags);
 204         bit = find_first_bit_inv(iv->avail, iv->bits);
 205         while (bit + num <= iv->bits) {
 206                 for (i = 1; i < num; i++)
 207                         if (!test_bit_inv(bit + i, iv->avail))
 208                                 break;
 209                 if (i >= num) {
 210                         /* Found a suitable block of irqs */
 211                         for (i = 0; i < num; i++)
 212                                 clear_bit_inv(bit + i, iv->avail);
 213                         if (bit + num >= iv->end)
 214                                 iv->end = bit + num + 1;
 215                         break;
 216                 }
 217                 bit = find_next_bit_inv(iv->avail, iv->bits, bit + i + 1);
 218         }
 219         if (bit + num > iv->bits)
 220                 bit = -1UL;
 221         spin_unlock_irqrestore(&iv->lock, flags);
 222         return bit;
 223 }
 224 EXPORT_SYMBOL(airq_iv_alloc);
 225
 226 /**
 227  * airq_iv_free - free irq bits of an interrupt vector
 228  * @iv: pointer to interrupt vector structure
 229  * @bit: number of the first irq bit to free
 230  * @num: number of consecutive irq bits to free
 231  */
 232 void airq_iv_free(struct airq_iv *iv, unsigned long bit, unsigned long num)
 233 {
 234         unsigned long i, flags;
 235
 236         if (!iv->avail || num == 0)
 237                 return;
 238         spin_lock_irqsave(&iv->lock, flags);
 239         for (i = 0; i < num; i++) {
 240                 /* Clear (possibly left over) interrupt bit */
 241                 clear_bit_inv(bit + i, iv->vector);
 242                 /* Make the bit positions available again */
 243                 set_bit_inv(bit + i, iv->avail);
 244         }
 245         if (bit + num >= iv->end) {
 246                 /* Find new end of bit-field */
 247                 while (iv->end > 0 && !test_bit_inv(iv->end - 1, iv->avail))
 248                         iv->end--;
 249         }
 250         spin_unlock_irqrestore(&iv->lock, flags);
 251 }
 252 EXPORT_SYMBOL(airq_iv_free);
 253
 254 /**
 255  * airq_iv_scan - scan interrupt vector for non-zero bits
 256  * @iv: pointer to interrupt vector structure
 257  * @start: bit number to start the search
 258  * @end: bit number to end the search
 259  *
 260  * Returns the bit number of the next non-zero interrupt bit, or
 261  * -1UL if the scan completed without finding any more any non-zero bits.
 262  */
 263 unsigned long airq_iv_scan(struct airq_iv *iv, unsigned long start,
 264                            unsigned long end)
 265 {
 266         unsigned long bit;
 267
 268         /* Find non-zero bit starting from 'ivs->next'. */
 269         bit = find_next_bit_inv(iv->vector, end, start);
 270         if (bit >= end)
 271                 return -1UL;
 272         clear_bit_inv(bit, iv->vector);
 273         return bit;
 274 }
 275 EXPORT_SYMBOL(airq_iv_scan);