drivers/s390/cio/airq.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *    Support for adapter interruptions
   4  *
   5  *    Copyright IBM Corp. 1999, 2007
   6  *    Author(s): Ingo Adlung <adlung@de.ibm.com>
   7  *               Cornelia Huck <cornelia.huck@de.ibm.com>
   8  *               Arnd Bergmann <arndb@de.ibm.com>
   9  *               Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/irq.h>
  14 #include <linux/kernel_stat.h>
  15 #include <linux/module.h>
  16 #include <linux/mutex.h>
  17 #include <linux/rculist.h>
  18 #include <linux/slab.h>
  19 #include <linux/dmapool.h>
  20
  21 #include <asm/airq.h>
  22 #include <asm/isc.h>
  23 #include <asm/cio.h>
  24
  25 #include "cio.h"
  26 #include "cio_debug.h"
  27 #include "ioasm.h"
  28
  29 static DEFINE_SPINLOCK(airq_lists_lock);
  30 static struct hlist_head airq_lists[MAX_ISC+1];
  31
  32 static struct dma_pool *airq_iv_cache;
  33
  34 /**
  35  * register_adapter_interrupt() - register adapter interrupt handler
  36  * @airq: pointer to adapter interrupt descriptor
  37  *
  38  * Returns 0 on success, or -EINVAL.
  39  */
  40 int register_adapter_interrupt(struct airq_struct *airq)
  41 {
  42         char dbf_txt[32];
  43
  44         if (!airq->handler || airq->isc > MAX_ISC)
  45                 return -EINVAL;
  46         if (!airq->lsi_ptr) {
  47                 airq->lsi_ptr = kzalloc(1, GFP_KERNEL);
  48                 if (!airq->lsi_ptr)
  49                         return -ENOMEM;
  50                 airq->flags |= AIRQ_PTR_ALLOCATED;
  51         }
  52         if (!airq->lsi_mask)
  53                 airq->lsi_mask = 0xff;
  54         snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%p", airq);
  55         CIO_TRACE_EVENT(4, dbf_txt);
  56         isc_register(airq->isc);
  57         spin_lock(&airq_lists_lock);
  58         hlist_add_head_rcu(&airq->list, &airq_lists[airq->isc]);
  59         spin_unlock(&airq_lists_lock);
  60         return 0;
  61 }
  62 EXPORT_SYMBOL(register_adapter_interrupt);
  63
  64 /**
  65  * unregister_adapter_interrupt - unregister adapter interrupt handler
  66  * @airq: pointer to adapter interrupt descriptor
  67  */
  68 void unregister_adapter_interrupt(struct airq_struct *airq)
  69 {
  70         char dbf_txt[32];
  71
  72         if (hlist_unhashed(&airq->list))
  73                 return;
  74         snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%p", airq);
  75         CIO_TRACE_EVENT(4, dbf_txt);
  76         spin_lock(&airq_lists_lock);
  77         hlist_del_rcu(&airq->list);
  78         spin_unlock(&airq_lists_lock);
  79         synchronize_rcu();
  80         isc_unregister(airq->isc);
  81         if (airq->flags & AIRQ_PTR_ALLOCATED) {
  82                 kfree(airq->lsi_ptr);
  83                 airq->lsi_ptr = NULL;
  84                 airq->flags &= ~AIRQ_PTR_ALLOCATED;
  85         }
  86 }
  87 EXPORT_SYMBOL(unregister_adapter_interrupt);
  88
  89 static irqreturn_t do_airq_interrupt(int irq, void *dummy)
  90 {
  91         struct tpi_info *tpi_info;
  92         struct airq_struct *airq;
  93         struct hlist_head *head;
  94
  95         set_cpu_flag(CIF_NOHZ_DELAY);
  96         tpi_info = &get_irq_regs()->tpi_info;
  97         trace_s390_cio_adapter_int(tpi_info);
  98         head = &airq_lists[tpi_info->isc];
  99         rcu_read_lock();
 100         hlist_for_each_entry_rcu(airq, head, list)
 101                 if ((*airq->lsi_ptr & airq->lsi_mask) != 0)
 102                         airq->handler(airq, !tpi_info->directed_irq);
 103         rcu_read_unlock();
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 void __init init_airq_interrupts(void)
 109 {
 110         irq_set_chip_and_handler(THIN_INTERRUPT,
 111                                  &dummy_irq_chip, handle_percpu_irq);
 112         if (request_irq(THIN_INTERRUPT, do_airq_interrupt, 0, "AIO", NULL))
 113                 panic("Failed to register AIO interrupt\n");
 114 }
 115
 116 static inline unsigned long iv_size(unsigned long bits)
 117 {
 118         return BITS_TO_LONGS(bits) * sizeof(unsigned long);
 119 }
 120
 121 /**
 122  * airq_iv_create - create an interrupt vector
 123  * @bits: number of bits in the interrupt vector
 124  * @flags: allocation flags
 125  *
 126  * Returns a pointer to an interrupt vector structure
 127  */
 128 struct airq_iv *airq_iv_create(unsigned long bits, unsigned long flags)
 129 {
 130         struct airq_iv *iv;
 131         unsigned long size;
 132
 133         iv = kzalloc(sizeof(*iv), GFP_KERNEL);
 134         if (!iv)
 135                 goto out;
 136         iv->bits = bits;
 137         iv->flags = flags;
 138         size = iv_size(bits);
 139
 140         if (flags & AIRQ_IV_CACHELINE) {
 141                 if ((cache_line_size() * BITS_PER_BYTE) < bits
 142                                 || !airq_iv_cache)
 143                         goto out_free;
 144
 145                 iv->vector = dma_pool_zalloc(airq_iv_cache, GFP_KERNEL,
 146                                              &iv->vector_dma);
 147                 if (!iv->vector)
 148                         goto out_free;
 149         } else {
 150                 iv->vector = cio_dma_zalloc(size);
 151                 if (!iv->vector)
 152                         goto out_free;
 153         }
 154         if (flags & AIRQ_IV_ALLOC) {
 155                 iv->avail = kmalloc(size, GFP_KERNEL);
 156                 if (!iv->avail)
 157                         goto out_free;
 158                 memset(iv->avail, 0xff, size);
 159                 iv->end = 0;
 160         } else
 161                 iv->end = bits;
 162         if (flags & AIRQ_IV_BITLOCK) {
 163                 iv->bitlock = kzalloc(size, GFP_KERNEL);
 164                 if (!iv->bitlock)
 165                         goto out_free;
 166         }
 167         if (flags & AIRQ_IV_PTR) {
 168                 size = bits * sizeof(unsigned long);
 169                 iv->ptr = kzalloc(size, GFP_KERNEL);
 170                 if (!iv->ptr)
 171                         goto out_free;
 172         }
 173         if (flags & AIRQ_IV_DATA) {
 174                 size = bits * sizeof(unsigned int);
 175                 iv->data = kzalloc(size, GFP_KERNEL);
 176                 if (!iv->data)
 177                         goto out_free;
 178         }
 179         spin_lock_init(&iv->lock);
 180         return iv;
 181
 182 out_free:
 183         kfree(iv->ptr);
 184         kfree(iv->bitlock);
 185         kfree(iv->avail);
 186         if (iv->flags & AIRQ_IV_CACHELINE && iv->vector)
 187                 dma_pool_free(airq_iv_cache, iv->vector, iv->vector_dma);
 188         else
 189                 cio_dma_free(iv->vector, size);
 190         kfree(iv);
 191 out:
 192         return NULL;
 193 }
 194 EXPORT_SYMBOL(airq_iv_create);
 195
 196 /**
 197  * airq_iv_release - release an interrupt vector
 198  * @iv: pointer to interrupt vector structure
 199  */
 200 void airq_iv_release(struct airq_iv *iv)
 201 {
 202         kfree(iv->data);
 203         kfree(iv->ptr);
 204         kfree(iv->bitlock);
 205         if (iv->flags & AIRQ_IV_CACHELINE)
 206                 dma_pool_free(airq_iv_cache, iv->vector, iv->vector_dma);
 207         else
 208                 cio_dma_free(iv->vector, iv_size(iv->bits));
 209         kfree(iv->avail);
 210         kfree(iv);
 211 }
 212 EXPORT_SYMBOL(airq_iv_release);
 213
 214 /**
 215  * airq_iv_alloc - allocate irq bits from an interrupt vector
 216  * @iv: pointer to an interrupt vector structure
 217  * @num: number of consecutive irq bits to allocate
 218  *
 219  * Returns the bit number of the first irq in the allocated block of irqs,
 220  * or -1UL if no bit is available or the AIRQ_IV_ALLOC flag has not been
 221  * specified
 222  */
 223 unsigned long airq_iv_alloc(struct airq_iv *iv, unsigned long num)
 224 {
 225         unsigned long bit, i, flags;
 226
 227         if (!iv->avail || num == 0)
 228                 return -1UL;
 229         spin_lock_irqsave(&iv->lock, flags);
 230         bit = find_first_bit_inv(iv->avail, iv->bits);
 231         while (bit + num <= iv->bits) {
 232                 for (i = 1; i < num; i++)
 233                         if (!test_bit_inv(bit + i, iv->avail))
 234                                 break;
 235                 if (i >= num) {
 236                         /* Found a suitable block of irqs */
 237                         for (i = 0; i < num; i++)
 238                                 clear_bit_inv(bit + i, iv->avail);
 239                         if (bit + num >= iv->end)
 240                                 iv->end = bit + num + 1;
 241                         break;
 242                 }
 243                 bit = find_next_bit_inv(iv->avail, iv->bits, bit + i + 1);
 244         }
 245         if (bit + num > iv->bits)
 246                 bit = -1UL;
 247         spin_unlock_irqrestore(&iv->lock, flags);
 248         return bit;
 249 }
 250 EXPORT_SYMBOL(airq_iv_alloc);
 251
 252 /**
 253  * airq_iv_free - free irq bits of an interrupt vector
 254  * @iv: pointer to interrupt vector structure
 255  * @bit: number of the first irq bit to free
 256  * @num: number of consecutive irq bits to free
 257  */
 258 void airq_iv_free(struct airq_iv *iv, unsigned long bit, unsigned long num)
 259 {
 260         unsigned long i, flags;
 261
 262         if (!iv->avail || num == 0)
 263                 return;
 264         spin_lock_irqsave(&iv->lock, flags);
 265         for (i = 0; i < num; i++) {
 266                 /* Clear (possibly left over) interrupt bit */
 267                 clear_bit_inv(bit + i, iv->vector);
 268                 /* Make the bit positions available again */
 269                 set_bit_inv(bit + i, iv->avail);
 270         }
 271         if (bit + num >= iv->end) {
 272                 /* Find new end of bit-field */
 273                 while (iv->end > 0 && !test_bit_inv(iv->end - 1, iv->avail))
 274                         iv->end--;
 275         }
 276         spin_unlock_irqrestore(&iv->lock, flags);
 277 }
 278 EXPORT_SYMBOL(airq_iv_free);
 279
 280 /**
 281  * airq_iv_scan - scan interrupt vector for non-zero bits
 282  * @iv: pointer to interrupt vector structure
 283  * @start: bit number to start the search
 284  * @end: bit number to end the search
 285  *
 286  * Returns the bit number of the next non-zero interrupt bit, or
 287  * -1UL if the scan completed without finding any more any non-zero bits.
 288  */
 289 unsigned long airq_iv_scan(struct airq_iv *iv, unsigned long start,
 290                            unsigned long end)
 291 {
 292         unsigned long bit;
 293
 294         /* Find non-zero bit starting from 'ivs->next'. */
 295         bit = find_next_bit_inv(iv->vector, end, start);
 296         if (bit >= end)
 297                 return -1UL;
 298         clear_bit_inv(bit, iv->vector);
 299         return bit;
 300 }
 301 EXPORT_SYMBOL(airq_iv_scan);
 302
 303 int __init airq_init(void)
 304 {
 305         airq_iv_cache = dma_pool_create("airq_iv_cache", cio_get_dma_css_dev(),
 306                                         cache_line_size(),
 307                                         cache_line_size(), PAGE_SIZE);
 308         if (!airq_iv_cache)
 309                 return -ENOMEM;
 310         return 0;
 311 }