a kernel module used to read chipid of cubieboard

chipid.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>

#include <linux/io.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

/* procfs routines */

int chipid_show(struct seq_file *p, void *v) {
#define SW_VA_SID_IO_BASE ((const volatile void __iomem*)0xf1c23800)
    return seq_printf(p, "Chipid\t\t: %08x-%08x-%08x-%08x\n",
            readl(SW_VA_SID_IO_BASE),
            readl(SW_VA_SID_IO_BASE + 0x4),
            readl(SW_VA_SID_IO_BASE + 0x8),
            readl(SW_VA_SID_IO_BASE + 0xC)
            );
}

int chipid_single_open(struct inode *inode, struct file *file) {
    return single_open(file, chipid_show, NULL);
}

struct file_operations chipid_single_seq_file_operations = {
    .open = chipid_single_open,
    .read = seq_read,
    .llseek = seq_lseek,
    .release = single_release,
};

struct proc_dir_entry *entry = NULL;


/* initialize routines */

static int __init chipid_init(void)
{
    printk(KERN_ALERT "chipid module loading ...\n");
    entry = proc_create("chipid", 0, NULL, &chipid_single_seq_file_operations);
    if (entry) {
        printk(KERN_ALERT "chipid module load ok, entry = %p\n", entry);
        return 0;
    }
    return -EFAULT;
}

static void __exit chipid_exit(void)
{
    printk(KERN_ALERT "chipid module unloading ..., entry = %p\n", entry);
    if (entry) {
        remove_proc_entry("chipid", NULL);
        printk(KERN_ALERT "chipid module unloaded.\n");
        entry = NULL;
    }
}

MODULE_AUTHOR("Xavier-Wang");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("kernel module used to get chipid of cubieboard!\n");
MODULE_ALIAS("retrieve chipid from procfs"); 
module_init(chipid_init);
module_exit(chipid_exit);

Makefile

obj-m := chipid.o

OUTPUT

sw@sw-acer:~/Work/Code/procfsk$ make -C /usr/src/linux-headers-3.8.0-25-generic SUBDIRS=$PWD modules
make:进入目录'/usr/src/linux-headers-3.8.0-25-generic'
  CC [M]  /home/sw/Work/Code/procfsk/chipid.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC      /home/sw/Work/Code/procfsk/chipid.mod.o
  LD [M]  /home/sw/Work/Code/procfsk/chipid.ko
make:离开目录“/usr/src/linux-headers-3.8.0-25-generic”
sw@sw-acer:~/Work/Code/procfsk$ sudo insmod chipid.kosw@sw-acer:~/Work/Code/procfsk$ cat /proc/chipid 
Chipid		: 63682074-65645f69-682a2076-2c766564
sw@sw-acer:~/Work/Code/procfsk$ sudo rmmod chipid sw@sw-acer:~/Work/Code/procfsk$ 
sw@sw-acer:~/Work/Code/procfsk$ dmesg | tail
[354923.091725] type=1400 audit(1373061974.062:42): apparmor="DENIED" operation="open" parent=3490 profile="/usr/bin/evince" name="/media/sw/Private/Downloads/vilua.love" pid=29762 comm="pool" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
[354923.092409] type=1400 audit(1373061974.062:43): apparmor="DENIED" operation="open" parent=3490 profile="/usr/bin/evince" name="/media/sw/Private/Downloads/Soundbanks.for.Guitar.Pro.6.rar.emule.td" pid=29762 comm="pool" requested_mask="r" denied_mask="r" fsuid=1000 ouid=0
[358156.365857] chipid module loading .../n
[358156.365875] chipid module load ok/nchipid module unloaded/n
[358575.034287] chipid module loading .../n<1>[358592.043926] chipid module unloading ..., entry = ce6bf480
[358592.043931] chipid module unloaded.
[358947.262917] chipid module loading ...
[358947.262942] chipid module load ok, entry = e5430ae0
[358970.715428] chipid module unloading ..., entry = e5430ae0
[358970.715434] chipid module unloaded.
sw@sw-acer:~/Work/Code/procfsk$ 

因为就这两天要把sd卡还给同学，所以打算睡觉前在nand上再编译一次，结果忘记编译前screen一下。
如果关掉工作站（省电）就会断开ssh， cb上的make就挂了。。。

终于编译完了，睡觉去。