ds18b20驱动运行错误

[root@FriendlyARM /Zhanguser]# ./Zhanguser

Start DS18B20

Unable to handle kernel NULL pointer dereference at virtual address 00000000

pgd = c3b98000

[00000000] *pgd=33bc3031, *pte=00000000, *ppte=00000000

Internal error: Oops: 817 [#1]

last sysfs file: /sys/devices/virtual/vc/vcsa4/dev

Modules linked in: Zhangdevdriver

CPU: 0 Not tainted (2.6.32.2-FriendlyARM #8)

PC is at DS18B20_process+0x68/0x8c [Zhangdevdriver]

LR is at DS18B20_read+0x78/0x90 [Zhangdevdriver]

pc : [<bf000378>] lr : [<bf00026c>] psr: 60000013

sp : c3b7ff28 ip : c3b7ff10 fp : c3b7ff3c

r10: 00000000 r9 : c3b7e000 r8 : c0030088

r7 : 00000003 r6 : c3b7ff78 r5 : 00000000 r4 : bf000678

r3 : 0000e9ff r2 : 000001ed r1 : fd060138 r0 : 00000050

Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user

Control: c000717f Table: 33b98000 DAC: 00000015

Process Zhanguser (pid: 733, stack limit = 0xc3b7e270)

Stack: (0xc3b7ff28 to 0xc3b80000)

ff20: becb7d0c becb7d0c c3b7ff54 c3b7ff40 bf0003b0 bf000320

ff40: c3b44280 becb7d0c c3b7ff74 c3b7ff58 c009bc10 bf0003ac c3b44280 00000000

ff60: 00000000 00000003 c3b7ffa4 c3b7ff78 c009bd1c c009bb74 00000000 00000000

ff80: ffffffff 00000000 0000000d 00000000 00000000 00000000 00000000 c3b7ffa8

ffa0: c002fee0 c009bce0 00000000 00000000 00000003 becb7d0c 00000002 becb7d0c

ffc0: 00000000 00000000 00000000 00000003 00000000 00000000 40024000 becb7d34

ffe0: 00000000 becb7d08 00008514 400daebc 60000010 00000003 00000000 00000000

Backtrace:

[<bf000310>] (DS18B20_process+0x0/0x8c [Zhangdevdriver]) from [<bf0003b0>] (DS18B20_readdata+0x14/0x3c [Zhangdevdriver])

r5:becb7d0c r4:becb7d0c

[<bf00039c>] (DS18B20_readdata+0x0/0x3c [Zhangdevdriver]) from [<c009bc10>] (vfs_read+0xac/0xe0)

r5:becb7d0c r4:c3b44280

[<c009bb64>] (vfs_read+0x0/0xe0) from [<c009bd1c>] (sys_read+0x4c/0x84)

r7:00000003 r6:00000000 r5:00000000 r4:c3b44280

[<c009bcd0>] (sys_read+0x0/0x84) from [<c002fee0>] (ret_fast_syscall+0x0/0x28)

r6:00000000 r5:00000000 r4:00000000

Code: e3a000be ebffff79 e5945040 ebffff9e (e5c50000)

---[ end trace 70797a630da78e0f ]---

one_wire_status: 4

]Segmentation fault

估计是我在进行内核地址和应用程序地址的传递出了问题，有空再弄，现在关键是论文和gre