| 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/module.h> |
| 13 | #include <linux/slab.h> |
| 14 | #include <linux/rcupdate.h> |
| 15 | |
| 16 | #include <asm/airq.h> |
| 17 | #include <asm/isc.h> |
| 18 | |
| 19 | #include "cio.h" |
| 20 | #include "cio_debug.h" |
| 21 | |
| 22 | #define NR_AIRQS 32 |
| 23 | #define NR_AIRQS_PER_WORD sizeof(unsigned long) |
| 24 | #define NR_AIRQ_WORDS (NR_AIRQS / NR_AIRQS_PER_WORD) |
| 25 | |
| 26 | union indicator_t { |
| 27 | unsigned long word[NR_AIRQ_WORDS]; |
| 28 | unsigned char byte[NR_AIRQS]; |
| 29 | } __attribute__((packed)); |
| 30 | |
| 31 | struct airq_t { |
| 32 | adapter_int_handler_t handler; |
| 33 | void *drv_data; |
| 34 | }; |
| 35 | |
| 36 | static union indicator_t indicators[MAX_ISC+1]; |
| 37 | static struct airq_t *airqs[MAX_ISC+1][NR_AIRQS]; |
| 38 | |
| 39 | static int register_airq(struct airq_t *airq, u8 isc) |
| 40 | { |
| 41 | int i; |
| 42 | |
| 43 | for (i = 0; i < NR_AIRQS; i++) |
| 44 | if (!cmpxchg(&airqs[isc][i], NULL, airq)) |
| 45 | return i; |
| 46 | return -ENOMEM; |
| 47 | } |
| 48 | |
| 49 | /** |
| 50 | * s390_register_adapter_interrupt() - register adapter interrupt handler |
| 51 | * @handler: adapter handler to be registered |
| 52 | * @drv_data: driver data passed with each call to the handler |
| 53 | * @isc: isc for which the handler should be called |
| 54 | * |
| 55 | * Returns: |
| 56 | * Pointer to the indicator to be used on success |
| 57 | * ERR_PTR() if registration failed |
| 58 | */ |
| 59 | void *s390_register_adapter_interrupt(adapter_int_handler_t handler, |
| 60 | void *drv_data, u8 isc) |
| 61 | { |
| 62 | struct airq_t *airq; |
| 63 | char dbf_txt[16]; |
| 64 | int ret; |
| 65 | |
| 66 | if (isc > MAX_ISC) |
| 67 | return ERR_PTR(-EINVAL); |
| 68 | airq = kmalloc(sizeof(struct airq_t), GFP_KERNEL); |
| 69 | if (!airq) { |
| 70 | ret = -ENOMEM; |
| 71 | goto out; |
| 72 | } |
| 73 | airq->handler = handler; |
| 74 | airq->drv_data = drv_data; |
| 75 | |
| 76 | ret = register_airq(airq, isc); |
| 77 | out: |
| 78 | snprintf(dbf_txt, sizeof(dbf_txt), "rairq:%d", ret); |
| 79 | CIO_TRACE_EVENT(4, dbf_txt); |
| 80 | if (ret < 0) { |
| 81 | kfree(airq); |
| 82 | return ERR_PTR(ret); |
| 83 | } else |
| 84 | return &indicators[isc].byte[ret]; |
| 85 | } |
| 86 | EXPORT_SYMBOL(s390_register_adapter_interrupt); |
| 87 | |
| 88 | /** |
| 89 | * s390_unregister_adapter_interrupt - unregister adapter interrupt handler |
| 90 | * @ind: indicator for which the handler is to be unregistered |
| 91 | * @isc: interruption subclass |
| 92 | */ |
| 93 | void s390_unregister_adapter_interrupt(void *ind, u8 isc) |
| 94 | { |
| 95 | struct airq_t *airq; |
| 96 | char dbf_txt[16]; |
| 97 | int i; |
| 98 | |
| 99 | i = (int) ((addr_t) ind) - ((addr_t) &indicators[isc].byte[0]); |
| 100 | snprintf(dbf_txt, sizeof(dbf_txt), "urairq:%d", i); |
| 101 | CIO_TRACE_EVENT(4, dbf_txt); |
| 102 | indicators[isc].byte[i] = 0; |
| 103 | airq = xchg(&airqs[isc][i], NULL); |
| 104 | /* |
| 105 | * Allow interrupts to complete. This will ensure that the airq handle |
| 106 | * is no longer referenced by any interrupt handler. |
| 107 | */ |
| 108 | synchronize_sched(); |
| 109 | kfree(airq); |
| 110 | } |
| 111 | EXPORT_SYMBOL(s390_unregister_adapter_interrupt); |
| 112 | |
| 113 | #define INDICATOR_MASK (0xffUL << ((NR_AIRQS_PER_WORD - 1) * 8)) |
| 114 | |
| 115 | void do_adapter_IO(u8 isc) |
| 116 | { |
| 117 | int w; |
| 118 | int i; |
| 119 | unsigned long word; |
| 120 | struct airq_t *airq; |
| 121 | |
| 122 | /* |
| 123 | * Access indicator array in word-sized chunks to minimize storage |
| 124 | * fetch operations. |
| 125 | */ |
| 126 | for (w = 0; w < NR_AIRQ_WORDS; w++) { |
| 127 | word = indicators[isc].word[w]; |
| 128 | i = w * NR_AIRQS_PER_WORD; |
| 129 | /* |
| 130 | * Check bytes within word for active indicators. |
| 131 | */ |
| 132 | while (word) { |
| 133 | if (word & INDICATOR_MASK) { |
| 134 | airq = airqs[isc][i]; |
| 135 | /* Make sure gcc reads from airqs only once. */ |
| 136 | barrier(); |
| 137 | if (likely(airq)) |
| 138 | airq->handler(&indicators[isc].byte[i], |
| 139 | airq->drv_data); |
| 140 | else |
| 141 | /* |
| 142 | * Reset ill-behaved indicator. |
| 143 | */ |
| 144 | indicators[isc].byte[i] = 0; |
| 145 | } |
| 146 | word <<= 8; |
| 147 | i++; |
| 148 | } |
| 149 | } |
| 150 | } |