linux中断--内核中断编程

　　Linux中断内核编程,　　前言,　　在前面分析了中断的基本原理后，就可以写一个内核中断程序来体验以下，也可以借此程序继续深入来了解内核中断的执行过程,　　一.内核中断程序：,　　我们还是来看一看成程序：,　　在看程序之前，要熟悉如何进行模块编程，和了解module_pararm()的用法。如果不熟悉的话请大家看，module_param()的学习和Linux内核模块编程，在此不作解释。,　　1.程序interrupt.c,　　[c-sharp] view plaincopy,　　1 /* 2 *file name :interrupt.c,　　3 *atuthor : john 4 */,　　5 #include 6 #include,　　7 #include 8 #include,　　9 10 MODULE_LICENSE("GPL");,　　11 static int irq; 12 char *interface;,　　13 static irqreturn_t myirq_handler(int irq,void *dev); 14,　　15 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 cant 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 plaincopy,　　1 obj-m:=tiger.o 2,　　3 CURRENT_PATH:=$(shell pwd) 4 VERSION_NUM:=$(shell uname -r),　　5 LINUX_PATH:=/usr/src/linux-headers-$(VERSION_NUM) 6,　　7 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 plaincopy,　　113struct 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 plaincopy,　　175struct 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_SMP,　　197 cpumask_var_t affinity; 198 const struct cpumask *affinity_hint;,　　199 unsigned int node; 200#ifdef CONFIG_GENERIC_PENDING_IRQ,　　201 cpumask_var_t pending_mask; 202#endif,　　203#endif 204 atomic_t threads_active;,　　205 wait_queue_head_t wait_for_threads; 206#ifdef CONFIG_PROC_FS,　　207 struct proc_dir_entry *dir; 208#endif,　　209 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_IRQ,　　217extern struct irq_desc irq_desc[NR_IRQS]; [c-sharp] view plaincopy,　　111struct 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); 130,　　131 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 plaincopy,　　135request_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 plaincopy,　　1006/** 1007 * request_threaded_irq - allocate an interrupt line,　　1008 * @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 default,　　1012 * primary handler is installed 1013 * @thread_fn: Function called from the irq handler thread,　　1014 * If NULL, no irq thread is created 1015 * @irqflags: Interrupt type flags,　　1016 * @devname: An ascii name for the claiming device 1017 * @dev_id: A cookie passed back to the handler function,　　1018 * 1019 * This call allocates interrupt resources and enables the,　　1020 * interrupt line and IRQ handling. From the point this 1021 * call is made your handler function may be invoked. Since,　　1022 * your handler function must clear any interrupt the board 1023 * raises, you must take care both to initialise your hardware,　　1024 * 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 ist,　　1028 * still called in hard interrupt context and has to check 1029 * whether the interrupt originates from the device. If yes it,　　1030 * needs to disable the interrupt on the device and return 1031 * IRQ_WAKE_THREAD which will wake up the handler thread and run,　　1032 * @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 the,　　1036 * 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_id,　　1040 * 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 entropy,　　1046 * IRQF_TRIGGER_* Specify active edge(s) or level 1047 *,　　1048 */ [c-sharp] view plaincopy,　　1049int 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; 1056,　　1057 /* 1058 * Sanity-check: shared interrupts must pass in a real dev-ID,,　　1059 * otherwise well have trouble later trying to figure out 1060 * which interrupt is which (messes up the interrupt freeing,　　1061 * 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; 1072,　　1073 if (!handler) { 1074 if (!thread_fn),　　1075 return -EINVAL; 1076 handler = irq_default_primary_handler;,　　1077 } 1078,　　1079 action = kzalloc(sizeof(struct irqaction), GFP_KERNEL); 1080 if (!action),　　1081 return -ENOMEM; 1082,　　1083 action->handler = handler; 1084 action->thread_fn = thread_fn;,　　1085 action->flags = irqflags; 1086 action->name = devname;,　　1087 action->dev_id = dev_id; 1088,　　1089 chip_bus_lock(irq, desc); 1090 retval = __setup_irq(irq, desc, action);,　　1091 chip_bus_sync_unlock(irq, desc); 1092,　　1093 if (retval) 1094 kfree(action);,　　1095 1096#ifdef CONFIG_DEBUG_SHIRQ,　　1097 if (!retval && (irqflags & IRQF_SHARED)) { 1098 /*,　　1099 * Its a shared IRQ -- the driver ought to be prepared for it 1100 * to happen immediately, so lets make sure....,　　1101 * We disable the irq to make sure that a real IRQ doesnt 1102 * run in parallel with our fake.,　　1103 */ 1104 unsigned long flags;,　　1105 1106 disable_irq(irq);,　　1107 local_irq_save(flags); 1108,　　1109 handler(irq, dev_id); 1110,　　1111 local_irq_restore(flags); 1112 enable_irq(irq);,　　1113 } 1114#endif,　　1115 return retval; 1116} [c-sharp] view plaincopy,　　993void free_irq(unsigned int irq, void *dev_id) 994{,　　995 struct irq_desc *desc = irq_to_desc(irq); 996,　　997 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},