Merge branch 'cputime' of git://git390.osdl.marist.edu/pub/scm/linux-2.6
[linux-2.6-block.git] / drivers / s390 / cio / airq.c
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1da177e4
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1/*
2 * drivers/s390/cio/airq.c
4e8e56c6 3 * Support for adapter interruptions
1da177e4 4 *
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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>
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10 */
11
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/slab.h>
15#include <linux/rcupdate.h>
16
4e8e56c6 17#include <asm/airq.h>
da7c5af8 18#include <asm/isc.h>
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19
20#include "cio.h"
1da177e4 21#include "cio_debug.h"
1da177e4 22
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23#define NR_AIRQS 32
24#define NR_AIRQS_PER_WORD sizeof(unsigned long)
25#define NR_AIRQ_WORDS (NR_AIRQS / NR_AIRQS_PER_WORD)
1da177e4 26
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27union indicator_t {
28 unsigned long word[NR_AIRQ_WORDS];
29 unsigned char byte[NR_AIRQS];
30} __attribute__((packed));
1da177e4 31
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32struct airq_t {
33 adapter_int_handler_t handler;
34 void *drv_data;
35};
1da177e4 36
da7c5af8
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37static union indicator_t indicators[MAX_ISC];
38static struct airq_t *airqs[MAX_ISC][NR_AIRQS];
1da177e4 39
da7c5af8 40static int register_airq(struct airq_t *airq, u8 isc)
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41{
42 int i;
1da177e4 43
4e8e56c6 44 for (i = 0; i < NR_AIRQS; i++)
da7c5af8 45 if (!cmpxchg(&airqs[isc][i], NULL, airq))
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46 return i;
47 return -ENOMEM;
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48}
49
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50/**
51 * s390_register_adapter_interrupt() - register adapter interrupt handler
52 * @handler: adapter handler to be registered
53 * @drv_data: driver data passed with each call to the handler
da7c5af8 54 * @isc: isc for which the handler should be called
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55 *
56 * Returns:
57 * Pointer to the indicator to be used on success
58 * ERR_PTR() if registration failed
59 */
60void *s390_register_adapter_interrupt(adapter_int_handler_t handler,
da7c5af8 61 void *drv_data, u8 isc)
1da177e4 62{
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63 struct airq_t *airq;
64 char dbf_txt[16];
1da177e4 65 int ret;
1da177e4 66
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67 if (isc > MAX_ISC)
68 return ERR_PTR(-EINVAL);
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69 airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL);
70 if (!airq) {
71 ret = -ENOMEM;
72 goto out;
1da177e4 73 }
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74 airq->handler = handler;
75 airq->drv_data = drv_data;
da7c5af8
CH
76
77 ret = register_airq(airq, isc);
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78out:
79 snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%d", ret);
80 CIO_TRACE_EVENT(4, dbf_txt);
da7c5af8
CH
81 if (ret < 0) {
82 kfree(airq);
4e8e56c6 83 return ERR_PTR(ret);
da7c5af8
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84 } else
85 return &indicators[isc].byte[ret];
1da177e4 86}
4e8e56c6 87EXPORT_SYMBOL(s390_register_adapter_interrupt);
1da177e4 88
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89/**
90 * s390_unregister_adapter_interrupt - unregister adapter interrupt handler
91 * @ind: indicator for which the handler is to be unregistered
da7c5af8 92 * @isc: interruption subclass
4e8e56c6 93 */
da7c5af8 94void s390_unregister_adapter_interrupt(void *ind, u8 isc)
1da177e4 95{
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96 struct airq_t *airq;
97 char dbf_txt[16];
98 int i;
1da177e4 99
da7c5af8 100 i = (int) ((addr_t) ind) - ((addr_t) &indicators[isc].byte[0]);
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101 snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%d", i);
102 CIO_TRACE_EVENT(4, dbf_txt);
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CH
103 indicators[isc].byte[i] = 0;
104 airq = xchg(&airqs[isc][i], NULL);
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105 /*
106 * Allow interrupts to complete. This will ensure that the airq handle
107 * is no longer referenced by any interrupt handler.
108 */
109 synchronize_sched();
110 kfree(airq);
1da177e4 111}
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112EXPORT_SYMBOL(s390_unregister_adapter_interrupt);
113
114#define INDICATOR_MASK (0xffUL << ((NR_AIRQS_PER_WORD - 1) * 8))
1da177e4 115
da7c5af8 116void do_adapter_IO(u8 isc)
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117{
118 int w;
119 int i;
120 unsigned long word;
121 struct airq_t *airq;
122
123 /*
124 * Access indicator array in word-sized chunks to minimize storage
125 * fetch operations.
126 */
127 for (w = 0; w < NR_AIRQ_WORDS; w++) {
da7c5af8 128 word = indicators[isc].word[w];
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129 i = w * NR_AIRQS_PER_WORD;
130 /*
131 * Check bytes within word for active indicators.
132 */
133 while (word) {
134 if (word & INDICATOR_MASK) {
da7c5af8 135 airq = airqs[isc][i];
4e8e56c6 136 if (likely(airq))
da7c5af8 137 airq->handler(&indicators[isc].byte[i],
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138 airq->drv_data);
139 else
140 /*
141 * Reset ill-behaved indicator.
142 */
da7c5af8 143 indicators[isc].byte[i] = 0;
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144 }
145 word <<= 8;
146 i++;
147 }
148 }
149}