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自己写了一个SPI设备的驱动,加载驱动后已经成功调用probe函数并创建了设备文件,问题是现在应用程序打开设备文件后就出现以下错误:将驱动中的open函数与release函数中其它删除只留下打印信息,应用程序中只留下打开和关闭设备文件代码,还是会出现如下错误,麻烦大侠帮忙解决以下该问题(已经调试好久了还没解决)
Unable to handle kernel NULL pointer dereference at virtual address 0000002fe driver uvcv
usbcore:
LR is at sys_close+0xa0/0xcc
pc : [<c0cde7c0>] lr : [<c0cde8d0>] psr: 80000013
sp : c082bf68 ip : c082bf88 fp : c082bf84
r10: 00000000 r9 : c082a000 r8 : c0c80008
r7 : 00000006 r6 : 0000001b r5 : c2b01cc0 r4 : 00000003
r3 : 00000007 r2 : 00000004 r1 : c2b01cc0 r0 : 0000001b
Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: c000717f Table: 32b84000 DAC: 00000015
Process app_gp21 (pid: 504, stack limit = 0xc082a268)
Stack: (0xc082bf68 to 0xc082c000)
bf60: 00000003 c2b01cc0 0000001b 00000006 c082bfa4 c082bf88
bf80: c0cde8d0 c0cde7c4 0000b494 00000000 0000b450 00000006 00000000 c082bfa8
bfa0: c0c7fe60 c0cde840 0000b494 00000000 00000003 00000000 00084f2c 00000001
bfc0: 0000b494 00000000 0000b450 00000006 00000000 00000000 00000000 be851b94
bfe0: 00000000 be851b78 00008278 0001522c 60000010 00000003 e5803008 e542c001
Backtrace:
[<c0cde7b4>] (filp_close+0x0/0x7c) from [<c0cde8d0>] (sys_close+0xa0/0xcc)
r7:00000006 r6:0000001b r5:c2b01cc0 r4:00000003
[<c0cde830>] (sys_close+0x0/0xcc) from [<c0c7fe60>] (ret_fast_syscall+0x0/0x2c)
r7:00000006 r6:0000b450 r5:00000000 r4:0000b494
Code: e89da800 e1a0c00d e92dd8f0 e24cb004 (e5903014)
---[ end trace d982a507971a8f45 ]---
Segmentation fault
驱动程序主要代码如下:- #define ARRYSIZE(x) ( sizeof(x)/ sizeof(x[0]))
- #define EINT3_IRQ 7
- #define SPI_MAJOR 252
- #define HIGH 1
- #define LOW 0
- extern int spi_register_driver(struct spi_driver *sdrv);
- extern int spi_write_then_read(struct spi_device *spi,const u8 *txbuf,unsigned n_tx,u8 *rxbuf,unsigned n_rx);
- extern int spi_sync(struct spi_device *spi,struct spi_message *message);
- extern struct class *__class_creat(struct module *owner ,const char *name,struct lock_class_key *key);
- extern int register_chrdev(unsigned int major,const char *name,const struct file_operations *fops);
- static char ev_irq = 0; // 定义表示中断发生的变量
- static DECLARE_WAIT_QUEUE_HEAD(measure_waitq); //定义一个等待队列
- struct spidev_data
- {
- dev_t devt;
- struct spi_device *spi ;
- };
- irqreturn_t mp_interrupt (int irq ,void *dev_id)
- {
- unsigned char value ;
- value = s3c2410_gpio_getpin(S3C2410_GPF3);
- if (!value)
- {
- ev_irq = 1 ;
- wake_up_interruptible (&measure_waitq);
- }
-
- }
- int Mp_Open (struct inode *inode ,struct file *file)
- {
- /* struct spidev_data *data_spi ;
- file->private_data = data_spi ;
- if (request_irq(EINT3_IRQ,mp_interrupt,IRQF_DISABLED|IRQF_TRIGGER_LOW,"mp",NULL)) //申请中断
- {
- printk ("request_irq error\n");
- } */
-
- printk("kernel open device success\n");
- }
-
- int Mp_Release (struct inode *inode ,struct file *filp)
- {
- printk("close device\n");
- }
- struct file_operations mp_fops =
- {
- .owner = THIS_MODULE ,
- .open = Mp_Open ,
- .release = Mp_Release ,
-
- };
- static struct class *spi_class ;
- static int Mp_Probe (struct spi_device *spi_dev)
- {
- int ret ;
- struct spidev_data *data_spi ;
- data_spi= kzalloc (sizeof(*data_spi),GFP_KERNEL);
- if(!data_spi)
- return -ENOMEM ;
- printk("kzalloc success\n");
- data_spi->spi = spi_dev ;
- data_spi->devt = MKDEV(SPI_MAJOR,0);
- device_create(spi_class,&spi_dev->dev,data_spi->devt,data_spi,"mp");
- spi_set_drvdata(spi_dev,data_spi);
- printk ("probe mp \n ");
- return 0 ;
-
- }
- static int Mp_Remove (struct spi_device *spi_dev)
- {
- struct spidev_data *data_spi ;
- cdev_del (&data_spi->spi);//注销字符设备
- return 0 ;
- }
- static struct spi_driver mp_driver =
- {
- .probe = Mp_Probe ,
- .remove = Mp_Remove ,
- .driver =
- {
- .name = "mp" ,
- .owner = THIS_MODULE ,
- }
- } ;
- static int __init Mp_init (void)
- {
- unsigned int ret ;
- ret = register_chrdev(SPI_MAJOR,"spi",&mp_fops);
- if (ret<0)
- {
- printk ("cdev add error\n");
- return ret;
- }
- spi_class = class_create (THIS_MODULE,"mp");
- if (IS_ERR(spi_class))
- {
- return PTR_ERR(spi_class);
- }
- return spi_register_driver (&mp_driver);
- }
- static void __exit Mp_exit (void)
- {
- spi_unregister_driver (&mp_driver);
- }
- module_init(Mp_init);
- module_exit(Mp_exit);
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("mp for EmbedSky SKY2440/TQ2440 Board");
复制代码 应用程序如下:- void main (int argc ,char **argv)
- {
- int fd ;
- fd = open("/dev/mp" ,O_RDWR);
- if (fd<0)
- {
- printf ("open device error\n");
- return ;
- }
- printf ("open seccuss\n");
- close(fd);
- }
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