Autor komentarzy: Grzegorz Całkowski (gc)
/* interrupt.h */ #ifndef _LINUX_INTERRUPT_H #define _LINUX_INTERRUPT_H #include <linux/kernel.h> #include <asm/bitops.h> struct irqaction { void (*handler)(int, void *, struct pt_regs *); unsigned long flags; unsigned long mask; const char *name; void *dev_id; struct irqaction *next; };
Deklaracje odnoszące się do zmiennych zdefiniowanych w softirq.c.
extern unsigned long intr_count; extern int bh_mask_count[32]; extern unsigned long bh_active; extern unsigned long bh_mask; extern void (*bh_base[32])(void); asmlinkage void do_bottom_half(void);
Definicje stałych określających kolejne poziomy "wolnych" przerwań. Niższy numer oznacza wyższy priorytet (procedura obsługi zostanie wywołana wcześniej - patrz do_bottom_half().
/* Who gets which entry in bh_base. Things which will occur most often should come first - in which case NET should be up the top with SERIAL/TQUEUE! */ enum { TIMER_BH = 0, CONSOLE_BH, TQUEUE_BH, DIGI_BH, SERIAL_BH, RISCOM8_BH, SPECIALIX_BH, BAYCOM_BH, NET_BH, IMMEDIATE_BH, KEYBOARD_BH, CYCLADES_BH, CM206_BH };
(gc)
Wstaw do tablicy bh_base na wskazanej pozycji adres funkcji. Zaznacz w bh_mask, że funkcja została tam umieszczona.
extern inline void init_bh(int nr, void (*routine)(void)) { bh_base[nr] = routine; bh_mask_count[nr] = 0; bh_mask |= 1 << nr; }
(gc)
Zaznacz w bh_active bit o wskazanym numerze. W do_bottom_half() zostanie wywołana funkcja obsługi przerwania o wskazanym numerze.
extern inline void mark_bh(int nr) { set_bit(nr, &bh_active); }
Zablokuj/odblokuj wywoływanie procedury obsługi przerwania o wskazanym numerze. Dzieki licznikowi wywołań bh_mask_count możliwe są zagnieżdżone wywołania disable_bh()/enable_bh().
/* * These use a mask count to correctly handle * nested disable/enable calls */ extern inline void disable_bh(int nr) { bh_mask &= ~(1 << nr); bh_mask_count[nr]++; } extern inline void enable_bh(int nr) { if (!--bh_mask_count[nr]) bh_mask |= 1 << nr; }
(gc)
/* * start_bh_atomic/end_bh_atomic also nest * naturally by using a counter */ extern inline void start_bh_atomic(void) { intr_count++; barrier(); } extern inline void end_bh_atomic(void) { barrier(); intr_count--; } /* * Autoprobing for irqs: * * probe_irq_on() and probe_irq_off() provide robust primitives * for accurate IRQ probing during kernel initialization. They are * reasonably simple to use, are not "fooled" by spurious interrupts, * and, unlike other attempts at IRQ probing, they do not get hung on * stuck interrupts (such as unused PS2 mouse interfaces on ASUS boards). * * For reasonably foolproof probing, use them as follows: * * 1. clear and/or mask the device's internal interrupt. * 2. sti(); * 3. irqs = probe_irq_on(); // "take over" all unassigned idle IRQs * 4. enable the device and cause it to trigger an interrupt. * 5. wait for the device to interrupt, using non-intrusive polling or a delay. * 6. irq = probe_irq_off(irqs); // get IRQ number, 0=none, negative=multiple * 7. service the device to clear its pending interrupt. * 8. loop again if paranoia is required. * * probe_irq_on() returns a mask of allocated irq's. * * probe_irq_off() takes the mask as a parameter, * and returns the irq number which occurred, * or zero if none occurred, or a negative irq number * if more than one irq occurred. */ extern unsigned long probe_irq_on(void); /* returns 0 on failure */ extern int probe_irq_off(unsigned long); /* returns 0 or negative on failure */ #endif