include/linux/interrupt.h

   1 /* interrupt.h */
   2 #ifndef _LINUX_INTERRUPT_H
   3 #define _LINUX_INTERRUPT_H
   4
   5 #include <linux/config.h>
   6 #include <linux/kernel.h>
   7 #include <linux/smp.h>
   8 #include <linux/cache.h>
   9
  10 #include <asm/bitops.h>
  11 #include <asm/atomic.h>
  12 #include <asm/ptrace.h>
  13
  14 struct irqaction {
  15         void (*handler)(int, void *, struct pt_regs *);
  16         unsigned long flags;
  17         unsigned long mask;
  18         const char *name;
  19         void *dev_id;
  20         struct irqaction *next;
  21 };
  22
  23
  24 /* Who gets which entry in bh_base.  Things which will occur most often
  25    should come first */
  26
  27 enum {
  28         TIMER_BH = 0,
  29         TQUEUE_BH,
  30         DIGI_BH,
  31         SERIAL_BH,
  32         RISCOM8_BH,
  33         SPECIALIX_BH,
  34         AURORA_BH,
  35         ESP_BH,
  36         SCSI_BH,
  37         IMMEDIATE_BH,
  38         CYCLADES_BH,
  39         CM206_BH,
  40         JS_BH,
  41         MACSERIAL_BH,
  42         ISICOM_BH
  43 };
  44
  45 #include <asm/hardirq.h>
  46 #include <asm/softirq.h>
  47
  48
  49
  50 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
  51    frequency threaded job scheduling. For almost all the purposes
  52    tasklets are more than enough. F.e. all serial device BHs et
  53    al. should be converted to tasklets, not to softirqs.
  54  */
  55
  56 enum
  57 {
  58         HI_SOFTIRQ=0,
  59         NET_TX_SOFTIRQ,
  60         NET_RX_SOFTIRQ,
  61         TASKLET_SOFTIRQ
  62 };
  63
  64 /* softirq mask and active fields moved to irq_cpustat_t in
  65  * asm/hardirq.h to get better cache usage.  KAO
  66  */
  67
  68 struct softirq_action
  69 {
  70         void    (*action)(struct softirq_action *);
  71         void    *data;
  72 };
  73
  74 asmlinkage void do_softirq(void);
  75 extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data);
  76
  77 static inline void __cpu_raise_softirq(int cpu, int nr)
  78 {
  79         softirq_active(cpu) |= (1<<nr);
  80 }
  81
  82
  83 /* I do not want to use atomic variables now, so that cli/sti */
  84 static inline void raise_softirq(int nr)
  85 {
  86         unsigned long flags;
  87
  88         local_irq_save(flags);
  89         __cpu_raise_softirq(smp_processor_id(), nr);
  90         local_irq_restore(flags);
  91 }
  92
  93 extern void softirq_init(void);
  94
  95
  96
  97 /* Tasklets --- multithreaded analogue of BHs.
  98
  99    Main feature differing them of generic softirqs: tasklet
 100    is running only on one CPU simultaneously.
 101
 102    Main feature differing them of BHs: different tasklets
 103    may be run simultaneously on different CPUs.
 104
 105    Properties:
 106    * If tasklet_schedule() is called, then tasklet is guaranteed
 107      to be executed on some cpu at least once after this.
 108    * If the tasklet is already scheduled, but its excecution is still not
 109      started, it will be executed only once.
 110    * If this tasklet is already running on another CPU (or schedule is called
 111      from tasklet itself), it is rescheduled for later.
 112    * Tasklet is strictly serialized wrt itself, but not
 113      wrt another tasklets. If client needs some intertask synchronization,
 114      he makes it with spinlocks.
 115  */
 116
 117 struct tasklet_struct
 118 {
 119         struct tasklet_struct *next;
 120         unsigned long state;
 121         atomic_t count;
 122         void (*func)(unsigned long);
 123         unsigned long data;
 124 };
 125
 126 #define DECLARE_TASKLET(name, func, data) \
 127 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
 128
 129 #define DECLARE_TASKLET_DISABLED(name, func, data) \
 130 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 131
 132
 133 enum
 134 {
 135         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
 136         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
 137 };
 138
 139 struct tasklet_head
 140 {
 141         struct tasklet_struct *list;
 142 } __attribute__ ((__aligned__(SMP_CACHE_BYTES)));
 143
 144 extern struct tasklet_head tasklet_vec[NR_CPUS];
 145 extern struct tasklet_head tasklet_hi_vec[NR_CPUS];
 146
 147 #ifdef CONFIG_SMP
 148 #define tasklet_trylock(t) (!test_and_set_bit(TASKLET_STATE_RUN, &(t)->state))
 149 #define tasklet_unlock_wait(t) while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { /* NOTHING */ }
 150 #define tasklet_unlock(t) clear_bit(TASKLET_STATE_RUN, &(t)->state)
 151 #else
 152 #define tasklet_trylock(t) 1
 153 #define tasklet_unlock_wait(t) do { } while (0)
 154 #define tasklet_unlock(t) do { } while (0)
 155 #endif
 156
 157 static inline void tasklet_schedule(struct tasklet_struct *t)
 158 {
 159         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
 160                 int cpu = smp_processor_id();
 161                 unsigned long flags;
 162
 163                 local_irq_save(flags);
 164                 t->next = tasklet_vec[cpu].list;
 165                 tasklet_vec[cpu].list = t;
 166                 __cpu_raise_softirq(cpu, TASKLET_SOFTIRQ);
 167                 local_irq_restore(flags);
 168         }
 169 }
 170
 171 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 172 {
 173         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
 174                 int cpu = smp_processor_id();
 175                 unsigned long flags;
 176
 177                 local_irq_save(flags);
 178                 t->next = tasklet_hi_vec[cpu].list;
 179                 tasklet_hi_vec[cpu].list = t;
 180                 __cpu_raise_softirq(cpu, HI_SOFTIRQ);
 181                 local_irq_restore(flags);
 182         }
 183 }
 184
 185
 186 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 187 {
 188         atomic_inc(&t->count);
 189 }
 190
 191 static inline void tasklet_disable(struct tasklet_struct *t)
 192 {
 193         tasklet_disable_nosync(t);
 194         tasklet_unlock_wait(t);
 195 }
 196
 197 static inline void tasklet_enable(struct tasklet_struct *t)
 198 {
 199         atomic_dec(&t->count);
 200 }
 201
 202 extern void tasklet_kill(struct tasklet_struct *t);
 203 extern void tasklet_init(struct tasklet_struct *t,
 204                          void (*func)(unsigned long), unsigned long data);
 205
 206 #ifdef CONFIG_SMP
 207
 208 #define SMP_TIMER_NAME(name) name##__thr
 209
 210 #define SMP_TIMER_DEFINE(name, task) \
 211 DECLARE_TASKLET(task, name##__thr, 0); \
 212 static void name (unsigned long dummy) \
 213 { \
 214         tasklet_schedule(&(task)); \
 215 }
 216
 217 #else /* CONFIG_SMP */
 218
 219 #define SMP_TIMER_NAME(name) name
 220 #define SMP_TIMER_DEFINE(name, task)
 221
 222 #endif /* CONFIG_SMP */
 223
 224
 225 /* Old BH definitions */
 226
 227 extern struct tasklet_struct bh_task_vec[];
 228
 229 /* It is exported _ONLY_ for wait_on_irq(). */
 230 extern spinlock_t global_bh_lock;
 231
 232 static inline void mark_bh(int nr)
 233 {
 234         tasklet_hi_schedule(bh_task_vec+nr);
 235 }
 236
 237 extern void init_bh(int nr, void (*routine)(void));
 238 extern void remove_bh(int nr);
 239
 240
 241 /*
 242  * Autoprobing for irqs:
 243  *
 244  * probe_irq_on() and probe_irq_off() provide robust primitives
 245  * for accurate IRQ probing during kernel initialization.  They are
 246  * reasonably simple to use, are not "fooled" by spurious interrupts,
 247  * and, unlike other attempts at IRQ probing, they do not get hung on
 248  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
 249  *
 250  * For reasonably foolproof probing, use them as follows:
 251  *
 252  * 1. clear and/or mask the device's internal interrupt.
 253  * 2. sti();
 254  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
 255  * 4. enable the device and cause it to trigger an interrupt.
 256  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
 257  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
 258  * 7. service the device to clear its pending interrupt.
 259  * 8. loop again if paranoia is required.
 260  *
 261  * probe_irq_on() returns a mask of allocated irq's.
 262  *
 263  * probe_irq_off() takes the mask as a parameter,
 264  * and returns the irq number which occurred,
 265  * or zero if none occurred, or a negative irq number
 266  * if more than one irq occurred.
 267  */
 268 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
 269 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
 270 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
 271
 272 #endif