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

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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 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 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

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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

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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 we'll 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 * 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); 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}