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最近我想在s3c2410的数据总线上放一个自己的设备，通过总线来给设备发送数据，我选用2410的nGCS4来用, 于是我看了cs8900a网卡的驱动程序，因为它在我的开发板上占用的是nGCS3的资源，想参考它来些我自己的驱动，然后我写了一个字符设备的驱动，写了一个应用程序，写这个字符设备，原以为能成功，但出现了错误，我的具体做法如下：

1：在smdk.h中定义好了物理地址和虚拟地址的映射

#define pLZJBUS_BASE 0x28000000

#define vLZJBUS_BASE 0xdf000000

2: 写了一个字符设备的驱动如下：

#include <linux/config.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/errno.h> #include <linux/spinlock.h> #include <linux/netdevice.h> #include <linux/etherdevice.h>

#include <linux/miscdevice.h> #include <linux/spinlock.h> #include <linux/fs.h> #include <linux/ioport.h> #include <linux/sched.h> #include <asm/io.h> #include <asm/irq.h> #include <asm/hardware.h> #include <asm/uaccess.h> #define DEVICE_NAME "lzjbus" #define BUS_MAJOR 172

static int bus_value=0; static int io = 0xdf000000; static unsigned long start,len; static void lzjbusinit(void) {

// BWSCON 和 BWSCON4 的设置都是参考网卡设置的

BWSCON = (BWSCON & ~(BWSCON_ST4 | BWSCON_WS4 | BWSCON_DW4)) | (BWSCON_ST4 | BWSCON_WS4 | BWSCON_DW(4,BWSCON_DW_16)); BWSCON &= 0xFFFBFFFF; BANKCON4= BANKCON_Tacs0 | BANKCON_Tcos4 | BANKCON_Tacc14 | BANKCON_Toch1 | BANKCON_Tcah4 | BANKCON_Tacp6 | BANKCON_PMC16; }

static int lzjbus_write(struct file *file, char *buffer, size_t count, loff_t *ppos) { copy_from_user(&bus_value,buffer,sizeof buffer); outw(bus_value,io); } static struct file_operations lzjbus_ops = { owner: THIS_MODULE, write: lzjbus_write, }; static devfs_handle_t devfs_handle;

static int __init bus_init(void) { int ret,status; start = vLZJBUS_BASE; len = 0xf; ret = register_chrdev(BUS_MAJOR,DEVICE_NAME,&lzjbus_ops); if(ret < 0) { printk("device register fail !!\n"); return ret; } status=check_region(start,len); if(status == 0) { printk("succed for io map!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n"); request_region(start,len,DEVICE_NAME); } else { printk("failed io map !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n"); return(status); }

lzjbusinit(); devfs_handle = devfs_register(NULL,DEVICE_NAME,DEVFS_FL_DEFAULT,BUS_MAJOR,0,S_IFCHR | S_IRUSR | S_IWUSR,&lzjbus_ops,NULL); return 0; } static void __exit bus_exit(void) { devfs_unregister(devfs_handle); release_region(start,len); unregister_chrdev(BUS_MAJOR,DEVICE_NAME); } module_init(bus_init); module_exit(bus_exit);

3：写了一个应用程序如下：

#include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <sys/ioctl.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <sys/select.h> #include <sys/time.h>

int main(void) { int buttons_fd; int key_value; key_value = 0xff; buttons_fd = open("/dev/lzjbus",O_WRONLY); if (buttons_fd < 0) { perror("open device buttons"); exit(1); } write(buttons_fd,&key_value,sizeof(key_value));

close(buttons_fd); return 0; }

此时我的设备并没有连在总线的数据线上，我只想看看我通过总线发送数据是否能成功。

驱动加到内核后在 /dev/lzjbus 设备 而且在/proc/ioports 有设备的地址范围

我以为一切都OK了呢，没想到一运行我的应用程序就报错了，我一查是 它 outw(bus_value,io); 这条语句出的错。

错误如下：

Unable to handle kernel paging request at virtual address df000000 pgd = c3cb4000 *pgd = 00000000, *pmd = 00000000 Internal error: Oops: ffffffff CPU: 0 pc : [<c00bec18>] lr : [<c00bebf8>] Not tainted sp : c3cbbf6c ip : 00000000 fp : c3cbbf78 r10: 40139280 r9 : c3cba000 r8 : bffffe80 r7 : 00000000 r6 : ffffffea r5 : c0366e20 r4 : 00000004 r3 : 000000ff r2 : c018c508 r1 : df000000 r0 : 00000000 Flags: nZcv IRQs on FIQs on Mode SVC_32 Segment user Control: C000317F Table: 33CB4000 DAC: 00000015 Process button (pid: 53, stackpage=c3cbb000) Stack: (0xc3cbbf5c to 0xc3cbc000) bf40: c00bebf8 bf60: c00bec18 40000013 ffffffff c3cbbfa4 c3cbbf7c c004a1e8 c00bebcc c3cbbf88 bf80: c0049a6c 40020c34 bffffeb4 020002e8 00000004 c001b864 00000000 c3cbbfa8 bfa0: c001b6e0 c004a11c 40020c34 c00217c8 00000003 bffffe80 00000004 bffffe80 bfc0: 40020c34 bffffeb4 020002e8 4000ee5c 00000001 0200045c 40139280 bffffe94 bfe0: 400e12a0 bffffe80 020004b8 400e12a4 60000010 00000003 fffff7ff ffffffff Backtrace: Function entered at [<c00bebbc>] from [<c004a1e8>] Function entered at [<c004a10c>] from [<c001b6e0>] r8 = C001B864 r7 = 00000004 r6 = 020002E8 r5 = BFFFFEB4 r4 = 40020C34 Code: e59f3014 e59f200c e5931000 e1d230b0 (e1c130b0) Segmentation fault

所以现在我就不知道该怎么做了，也不知道为什么会出现这个错误。

请大家帮忙看看。给些方法。谢谢！！！！