linux中斷--核心中斷編程

Linux中斷核心編程
前言
在前面分析了中斷的基本原理後，就可以寫一個核心中斷程式來體驗以下，也可以藉此程式繼續深入來瞭解核心中斷的執行過程
一.核心中斷程式：
我們還是來看一看成程式：
在看程式之前，要熟悉如何進行模組編程，和瞭解module_pararm()的用法。如果不熟悉的話請大家看，module_param()的學習和Linux核心模組編程，在此不作解釋。
1.程式interrupt.c
[c-sharp] view plaincopy
1 /* 2 *file name :interrupt.c3 *atuthor : john 4 */5 #include<linux/init.h> 6 #include<linux/module.h>7 #include<linux/kernel.h> 8 #include<linux/interrupt.h>9 10 MODULE_LICENSE("GPL");11 static int irq; 12 char *interface;13 static irqreturn_t myirq_handler(int irq,void *dev); 1415 static int __init myirq_init(void) 16 {17 printk("the module is working!/n"); 18 printk("the irq is ready for working!/n");19 if(request_irq(irq,myirq_handler,IRQF_SHARED,interface,&irq)){ 20 printk(KERN_ERR "%s interrrupt can't register %d IRQ /n",interface,irq);21 return -EIO; 22 }23 printk("%s request %d IRQ/n",interface,irq); 24 return 0;25 } 26 static irqreturn_t myirq_handler(int irq,void *dev)27 { 28 printk("%d IRQ is working/n",irq);29 return IRQ_NONE; 30 }31 static void __exit myirq_exit(void) 32 {33 printk("the module is leaving!/n"); 34 printk("the irq is bye bye!/n");35 free_irq(irq,&irq); 36 printk("%s interrupt free %d IRQ/n",interface,irq);37 38 }39 module_init(myirq_init); 0 module_exit(myirq_exit);41 module_param(interface,charp,0644); 42 module_param(irq,int,0644);43 [c-sharp] view plaincopy1 obj-m:=tiger.o 23 CURRENT_PATH:=$(shell pwd) 4 VERSION_NUM:=$(shell uname -r)5 LINUX_PATH:=/usr/src/linux-headers-$(VERSION_NUM) 67 8 all :9 make -C $(LINUX_PATH) M=$(CURRENT_PATH) modules 10 clean:11 make -C $(LINUX_PATH) M=$(CURRENT_PATH) clean [c-sharp] view plaincopy/* * These flags used only by the kernel as part of the* irq handling routines. ** IRQF_DISABLED - keep irqs disabled when calling the action handler * IRQF_SAMPLE_RANDOM - irq is used to feed the random generator* IRQF_SHARED - allow sharing the irq among several devices * IRQF_PROBE_SHARED - set by callers when they expect sharing mismatches to occur* IRQF_TIMER - Flag to mark this interrupt as timer interrupt * IRQF_PERCPU - Interrupt is per cpu* IRQF_NOBALANCING - Flag to exclude this interrupt from irq balancing * IRQF_IRQPOLL - Interrupt is used for polling (only the interrupt that is* registered first in an shared interrupt is considered for * performance reasons)*/ #define IRQF_DISABLED 0x00000020#define IRQF_SAMPLE_RANDOM 0x00000040 #define IRQF_SHARED 0x00000080#define IRQF_PROBE_SHARED 0x00000100 #define IRQF_TIMER 0x00000200#define IRQF_PERCPU 0x00000400 #define IRQF_NOBALANCING 0x00000800#define IRQF_IRQPOLL 0x00001000
[c-sharp] view plaincopy113struct irqaction { 114 irq_handler_t handler;115 unsigned long flags; 116 const char *name;117 void *dev_id; 118 struct irqaction *next;119 int irq; 120 struct proc_dir_entry *dir;121 irq_handler_t thread_fn; 122 struct task_struct *thread;123 unsigned long thread_flags; 124};125 [c-sharp] view plaincopy175struct irq_desc { 176 unsigned int irq;177 struct timer_rand_state *timer_rand_state; 178 unsigned int *kstat_irqs;179#ifdef CONFIG_INTR_REMAP 180 struct irq_2_iommu *irq_2_iommu;181#endif 182 irq_flow_handler_t handle_irq;183 struct irq_chip *chip; 184 struct msi_desc *msi_desc;185 void *handler_data; 186 void *chip_data;187 struct irqaction *action; /* IRQ action list */ 188 unsigned int status; /* IRQ status */189 190 unsigned int depth; /* nested irq disables */191 unsigned int wake_depth; /* nested wake enables */ 192 unsigned int irq_count; /* For detecting broken IRQs */193 unsigned long last_unhandled; /* Aging timer for unhandled count */ 194 unsigned int irqs_unhandled;195 raw_spinlock_t lock; 196#ifdef CONFIG_SMP197 cpumask_var_t affinity; 198 const struct cpumask *affinity_hint;199 unsigned int node; 200#ifdef CONFIG_GENERIC_PENDING_IRQ201 cpumask_var_t pending_mask; 202#endif203#endif 204 atomic_t threads_active;205 wait_queue_head_t wait_for_threads; 206#ifdef CONFIG_PROC_FS207 struct proc_dir_entry *dir; 208#endif209 const char *name; 210} ____cacheline_internodealigned_in_smp;211 212extern void arch_init_copy_chip_data(struct irq_desc *old_desc,213 struct irq_desc *desc, int node); 214extern void arch_free_chip_data(struct irq_desc *old_desc, struct irq_desc *desc);215 216#ifndef CONFIG_SPARSE_IRQ217extern struct irq_desc irq_desc[NR_IRQS]; [c-sharp] view plaincopy111struct irq_chip { 112 const char *name;113 unsigned int (*startup)(unsigned int irq); 114 void (*shutdown)(unsigned int irq);115 void (*enable)(unsigned int irq); 116 void (*disable)(unsigned int irq);117 118 void (*ack)(unsigned int irq);119 void (*mask)(unsigned int irq); 120 void (*mask_ack)(unsigned int irq);121 void (*unmask)(unsigned int irq); 122 void (*eoi)(unsigned int irq);123 124 void (*end)(unsigned int irq);125 int (*set_affinity)(unsigned int irq, 126 const struct cpumask *dest);127 int (*retrigger)(unsigned int irq); 128 int (*set_type)(unsigned int irq, unsigned int flow_type);129 int (*set_wake)(unsigned int irq, unsigned int on); 130131 void (*bus_lock)(unsigned int irq); 132 void (*bus_sync_unlock)(unsigned int irq);133 134 /* Currently used only by UML, might disappear one day.*/135#ifdef CONFIG_IRQ_RELEASE_METHOD 136 void (*release)(unsigned int irq, void *dev_id);137#endif 138 /*139 * For compatibility, ->typename is copied into ->name. 140 * Will disappear.141 */ 142 const char *typename;143}; 144
[c-sharp] view plaincopy135request_irq(unsigned int irq, irq_handler_t handler, unsigned long flags, 136 const char *name, void *dev)137{ 138 return request_threaded_irq(irq, handler, NULL, flags, name, dev);139} 140 [c-sharp] view plaincopy1006/** 1007 * request_threaded_irq - allocate an interrupt line1008 * @irq: Interrupt line to allocate 1009 * @handler: Function to be called when the IRQ occurs.1010 * Primary handler for threaded interrupts 1011 * If NULL and thread_fn != NULL the default1012 * primary handler is installed 1013 * @thread_fn: Function called from the irq handler thread1014 * If NULL, no irq thread is created 1015 * @irqflags: Interrupt type flags1016 * @devname: An ascii name for the claiming device 1017 * @dev_id: A cookie passed back to the handler function1018 * 1019 * This call allocates interrupt resources and enables the1020 * interrupt line and IRQ handling. From the point this 1021 * call is made your handler function may be invoked. Since1022 * your handler function must clear any interrupt the board 1023 * raises, you must take care both to initialise your hardware1024 * and to set up the interrupt handler in the right order. 1025 *1026 * If you want to set up a threaded irq handler for your device 1027 * then you need to supply @handler and @thread_fn. @handler ist1028 * still called in hard interrupt context and has to check 1029 * whether the interrupt originates from the device. If yes it1030 * needs to disable the interrupt on the device and return 1031 * IRQ_WAKE_THREAD which will wake up the handler thread and run1032 * @thread_fn. This split handler design is necessary to support 1033 * shared interrupts.1034 * 1035 * Dev_id must be globally unique. Normally the address of the1036 * device data structure is used as the cookie. Since the handler 1037 * receives this value it makes sense to use it.1038 * 1039 * If your interrupt is shared you must pass a non NULL dev_id1040 * as this is required when freeing the interrupt. 1041 *1042 * Flags: 1043 *1044 * IRQF_SHARED Interrupt is shared 1045 * IRQF_SAMPLE_RANDOM The interrupt can be used for entropy1046 * IRQF_TRIGGER_* Specify active edge(s) or level 1047 *1048 */ [c-sharp] view plaincopy1049int request_threaded_irq(unsigned int irq, irq_handler_t handler, 1050 irq_handler_t thread_fn, unsigned long irqflags,1051 const char *devname, void *dev_id) 1052{1053 struct irqaction *action; 1054 struct irq_desc *desc;1055 int retval; 10561057 /* 1058 * Sanity-check: shared interrupts must pass in a real dev-ID,1059 * otherwise we'll have trouble later trying to figure out 1060 * which interrupt is which (messes up the interrupt freeing1061 * logic etc). 1062 */1063 if ((irqflags & IRQF_SHARED) && !dev_id) 1064 return -EINVAL;1065 1066 desc = irq_to_desc(irq);1067 if (!desc) 1068 return -EINVAL;1069 1070 if (desc->status & IRQ_NOREQUEST)1071 return -EINVAL; 10721073 if (!handler) { 1074 if (!thread_fn)1075 return -EINVAL; 1076 handler = irq_default_primary_handler;1077 } 10781079 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL); 1080 if (!action)1081 return -ENOMEM; 10821083 action->handler = handler; 1084 action->thread_fn = thread_fn;1085 action->flags = irqflags; 1086 action->name = devname;1087 action->dev_id = dev_id; 10881089 chip_bus_lock(irq, desc); 1090 retval = __setup_irq(irq, desc, action);1091 chip_bus_sync_unlock(irq, desc); 10921093 if (retval) 1094 kfree(action);1095 1096#ifdef CONFIG_DEBUG_SHIRQ1097 if (!retval && (irqflags & IRQF_SHARED)) { 1098 /*1099 * It's a shared IRQ -- the driver ought to be prepared for it 1100 * to happen immediately, so let's make sure....1101 * We disable the irq to make sure that a 'real' IRQ doesn't 1102 * run in parallel with our fake.1103 */ 1104 unsigned long flags;1105 1106 disable_irq(irq);1107 local_irq_save(flags); 11081109 handler(irq, dev_id); 11101111 local_irq_restore(flags); 1112 enable_irq(irq);1113 } 1114#endif1115 return retval; 1116} [c-sharp] view plaincopy993void free_irq(unsigned int irq, void *dev_id) 994{995 struct irq_desc *desc = irq_to_desc(irq); 996997 if (!desc) 998 return;999 1000 chip_bus_lock(irq, desc);1001 kfree(__free_irq(irq, dev_id)); 1002 chip_bus_sync_unlock(irq, desc);1003}