2008 May 13th Tuesday (五月 十三日 火曜日）

To use interrupt. #include <linux/kernel.h> /*We're doing kernel work*/ #include <linux/module.h> /*Specifically, a module*/ #include <linux/sched.h> #include <linux/workqueue.h> #include <linux/interrupt.h> /*We want an interrupt*/ #include <asm/io.h> #define MY_WORK_QUEUE_NAME "WQsched.c" static struct workqueue_struct *my_workqueue; /* * This will get called by the kernel as soon as it's safe * to do everything normally allowed by kernel modules. */ static void got_char(void *scancode) {     printk("ScanCode%x%s./n",         (int)*((char*)scancode)&0x7F,         *((char*)scancode)&0x80?"Released":"Pressed"); } /* * This function services keyboard interrupts. It reads the relevant * information from the keyboard and then puts the non time critical * part into the work queue. This will be run when the kernel considers it safe. */ irqreturn_t irq_handler(int irq, void *dev_id, struct pt_regs *regs) {     /*     * This variables are static because they need to be     * accessible (through pointers) to the bottom halfroutine.     */     static int initialised=0;     static unsigned char scancode;     static struct work_struct task;     unsigned char status;         /*     * Read keyboard status     */     status=inb(0x64);     scancode=inb(0x60);     if(initialised==0){         INIT_WORK(&task,got_char,&scancode);         initialised=1;     } else {         PREPARE_WORK(&task,got_char,&scancode);     }     queue_work(my_workqueue,&task);     return IRQ_HANDLED; } int init_module() {     my_workqueue=create_workqueue(MY_WORK_QUEUE_NAME);     /*     * Since the keyboard handler won't co-exist with another handler,     * such as us, we have to disable it (free its IRQ) before we do     * anything. Since we don't know where it is, there's no way to     * reinstate it later - so the computer will have to be rebooted     * whenwe'redone.     */     free_irq(1,NULL);         /*     * Request IRQ 1, the keyboard IRQ, to go to our irq_handler.     * SA_SHIRQ means we're willing to have othe handlers on this IRQ.     * SA_INTERRUPT can be used to make the handler into a fast interrupt.     */     return request_irq(1, /*The number of the keyboard IRQ on PCs*/             irq_handler, /*ourhandler*/             SA_SHIRQ,"test_keyboard_irq_handler",             (void*)(irq_handler)); } voidcleanup_module() {     /*     * This is only here for completeness. It's totally irrelevant, since     * we don't have a way to restore the normal keyboard interruptsothe     * computer is completely useless and has to be rebooted.     */     free_irq(1,NULL); } MODULE_LICENSE("GPL");