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/linkage.h>
   8 #include <linux/bitops.h>
   9 #include <linux/preempt.h>
  10 #include <asm/atomic.h>
  11 #include <asm/hardirq.h>
  12 #include <asm/ptrace.h>
  13 #include <asm/system.h>
  14
  15 /*
  16  * For 2.4.x compatibility, 2.4.x can use
  17  *
  18  *      typedef void irqreturn_t;
  19  *      #define IRQ_NONE
  20  *      #define IRQ_HANDLED
  21  *      #define IRQ_RETVAL(x)
  22  *
  23  * To mix old-style and new-style irq handler returns.
  24  *
  25  * IRQ_NONE means we didn't handle it.
  26  * IRQ_HANDLED means that we did have a valid interrupt and handled it.
  27  * IRQ_RETVAL(x) selects on the two depending on x being non-zero (for handled)
  28  */
  29 typedef int irqreturn_t;
  30
  31 #define IRQ_NONE        (0)
  32 #define IRQ_HANDLED     (1)
  33 #define IRQ_RETVAL(x)   ((x) != 0)
  34
  35 struct irqaction {
  36         irqreturn_t (*handler)(int, void *, struct pt_regs *);
  37         unsigned long flags;
  38         unsigned long mask;
  39         const char *name;
  40         void *dev_id;
  41         struct irqaction *next;
  42 };
  43
  44 extern irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs);
  45 extern int request_irq(unsigned int,
  46                        irqreturn_t (*handler)(int, void *, struct pt_regs *),
  47                        unsigned long, const char *, void *);
  48 extern void free_irq(unsigned int, void *);
  49
  50 /*
  51  * Temporary defines for UP kernels, until all code gets fixed.
  52  */
  53 #ifndef CONFIG_SMP
  54 # define cli()                  local_irq_disable()
  55 # define sti()                  local_irq_enable()
  56 # define save_flags(x)          local_save_flags(x)
  57 # define restore_flags(x)       local_irq_restore(x)
  58 # define save_and_cli(x)        local_irq_save(x)
  59 #endif
  60
  61 /* SoftIRQ primitives.  */
  62 #define local_bh_disable() \
  63                 do { preempt_count() += SOFTIRQ_OFFSET; barrier(); } while (0)
  64 #define __local_bh_enable() \
  65                 do { barrier(); preempt_count() -= SOFTIRQ_OFFSET; } while (0)
  66
  67 extern void local_bh_enable(void);
  68
  69 /* PLEASE, avoid to allocate new softirqs, if you need not _really_ high
  70    frequency threaded job scheduling. For almost all the purposes
  71    tasklets are more than enough. F.e. all serial device BHs et
  72    al. should be converted to tasklets, not to softirqs.
  73  */
  74
  75 enum
  76 {
  77         HI_SOFTIRQ=0,
  78         TIMER_SOFTIRQ,
  79         NET_TX_SOFTIRQ,
  80         NET_RX_SOFTIRQ,
  81         SCSI_SOFTIRQ,
  82         TASKLET_SOFTIRQ
  83 };
  84
  85 /* softirq mask and active fields moved to irq_cpustat_t in
  86  * asm/hardirq.h to get better cache usage.  KAO
  87  */
  88
  89 struct softirq_action
  90 {
  91         void    (*action)(struct softirq_action *);
  92         void    *data;
  93 };
  94
  95 asmlinkage void do_softirq(void);
  96 extern void open_softirq(int nr, void (*action)(struct softirq_action*), void *data);
  97 extern void softirq_init(void);
  98 #define __raise_softirq_irqoff(nr) do { local_softirq_pending() |= 1UL << (nr); } while (0)
  99 extern void FASTCALL(raise_softirq_irqoff(unsigned int nr));
 100 extern void FASTCALL(raise_softirq(unsigned int nr));
 101
 102 #ifndef invoke_softirq
 103 #define invoke_softirq() do_softirq()
 104 #endif
 105
 106
 107 /* Tasklets --- multithreaded analogue of BHs.
 108
 109    Main feature differing them of generic softirqs: tasklet
 110    is running only on one CPU simultaneously.
 111
 112    Main feature differing them of BHs: different tasklets
 113    may be run simultaneously on different CPUs.
 114
 115    Properties:
 116    * If tasklet_schedule() is called, then tasklet is guaranteed
 117      to be executed on some cpu at least once after this.
 118    * If the tasklet is already scheduled, but its excecution is still not
 119      started, it will be executed only once.
 120    * If this tasklet is already running on another CPU (or schedule is called
 121      from tasklet itself), it is rescheduled for later.
 122    * Tasklet is strictly serialized wrt itself, but not
 123      wrt another tasklets. If client needs some intertask synchronization,
 124      he makes it with spinlocks.
 125  */
 126
 127 struct tasklet_struct
 128 {
 129         struct tasklet_struct *next;
 130         unsigned long state;
 131         atomic_t count;
 132         void (*func)(unsigned long);
 133         unsigned long data;
 134 };
 135
 136 #define DECLARE_TASKLET(name, func, data) \
 137 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(0), func, data }
 138
 139 #define DECLARE_TASKLET_DISABLED(name, func, data) \
 140 struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 141
 142
 143 enum
 144 {
 145         TASKLET_STATE_SCHED,    /* Tasklet is scheduled for execution */
 146         TASKLET_STATE_RUN       /* Tasklet is running (SMP only) */
 147 };
 148
 149 #ifdef CONFIG_SMP
 150 static inline int tasklet_trylock(struct tasklet_struct *t)
 151 {
 152         return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 153 }
 154
 155 static inline void tasklet_unlock(struct tasklet_struct *t)
 156 {
 157         smp_mb__before_clear_bit();
 158         clear_bit(TASKLET_STATE_RUN, &(t)->state);
 159 }
 160
 161 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 162 {
 163         while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
 164 }
 165 #else
 166 #define tasklet_trylock(t) 1
 167 #define tasklet_unlock_wait(t) do { } while (0)
 168 #define tasklet_unlock(t) do { } while (0)
 169 #endif
 170
 171 extern void FASTCALL(__tasklet_schedule(struct tasklet_struct *t));
 172
 173 static inline void tasklet_schedule(struct tasklet_struct *t)
 174 {
 175         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 176                 __tasklet_schedule(t);
 177 }
 178
 179 extern void FASTCALL(__tasklet_hi_schedule(struct tasklet_struct *t));
 180
 181 static inline void tasklet_hi_schedule(struct tasklet_struct *t)
 182 {
 183         if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
 184                 __tasklet_hi_schedule(t);
 185 }
 186
 187
 188 static inline void tasklet_disable_nosync(struct tasklet_struct *t)
 189 {
 190         atomic_inc(&t->count);
 191         smp_mb__after_atomic_inc();
 192 }
 193
 194 static inline void tasklet_disable(struct tasklet_struct *t)
 195 {
 196         tasklet_disable_nosync(t);
 197         tasklet_unlock_wait(t);
 198         smp_mb();
 199 }
 200
 201 static inline void tasklet_enable(struct tasklet_struct *t)
 202 {
 203         smp_mb__before_atomic_dec();
 204         atomic_dec(&t->count);
 205 }
 206
 207 static inline void tasklet_hi_enable(struct tasklet_struct *t)
 208 {
 209         smp_mb__before_atomic_dec();
 210         atomic_dec(&t->count);
 211 }
 212
 213 extern void tasklet_kill(struct tasklet_struct *t);
 214 extern void tasklet_init(struct tasklet_struct *t,
 215                          void (*func)(unsigned long), unsigned long data);
 216
 217 /*
 218  * Autoprobing for irqs:
 219  *
 220  * probe_irq_on() and probe_irq_off() provide robust primitives
 221  * for accurate IRQ probing during kernel initialization.  They are
 222  * reasonably simple to use, are not "fooled" by spurious interrupts,
 223  * and, unlike other attempts at IRQ probing, they do not get hung on
 224  * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards).
 225  *
 226  * For reasonably foolproof probing, use them as follows:
 227  *
 228  * 1. clear and/or mask the device's internal interrupt.
 229  * 2. sti();
 230  * 3. irqs = probe_irq_on();      // "take over" all unassigned idle IRQs
 231  * 4. enable the device and cause it to trigger an interrupt.
 232  * 5. wait for the device to interrupt, using non-intrusive polling or a delay.
 233  * 6. irq = probe_irq_off(irqs);  // get IRQ number, 0=none, negative=multiple
 234  * 7. service the device to clear its pending interrupt.
 235  * 8. loop again if paranoia is required.
 236  *
 237  * probe_irq_on() returns a mask of allocated irq's.
 238  *
 239  * probe_irq_off() takes the mask as a parameter,
 240  * and returns the irq number which occurred,
 241  * or zero if none occurred, or a negative irq number
 242  * if more than one irq occurred.
 243  */
 244 extern unsigned long probe_irq_on(void);        /* returns 0 on failure */
 245 extern int probe_irq_off(unsigned long);        /* returns 0 or negative on failure */
 246 extern unsigned int probe_irq_mask(unsigned long);      /* returns mask of ISA interrupts */
 247
 248 #endif