2009/10/1 Harinderjit Singh Sandhu <harinderjitss@xxxxxxxxx>:
>
> this is the code for the small module that i wrote
> ------------------------------
> ----------------------------------
>
> #include <linux/module.h>
> #include <linux/errno.h>
> #include <linux/fs.h>
> #include <linux/mm.h>
> #include <linux/interrupt.h>
> #include <linux/sched.h>
> #include <asm/uaccess.h>
> #include <asm/io.h>
> #define SKELETON_MAJOR 32
> #define SKELETON_NAME "skeleton"
> #define BASEPORT 0x378
> #define PARALLEL_PORT_INTERRUPT 7
> #define CASE1 1
> #define CASE2 2
> static int data;
> static unsigned int counter = 0;
> static char string [128];
> static int data;
> //static int interruptcount = 0;
>
> DECLARE_WAIT_QUEUE_HEAD(skeleton_wait);
> static int data_not_ready = 1;
>
> // open function - called when the "file" /dev/skeleton is opened in
> userspace
> static int skeleton_open (struct inode *inode, struct file *file) {
> printk("skeleton_open\n");
> // we could do some checking on the flags supplied by "open"
> // i.e. O_NONBLOCK
> // -> set some flag to disable interruptible_sleep_on in skeleton_read
> return 0;
> }
>
> // close function - called when the "file" /dev/skeleton is closed in
> userspace
> static int skeleton_release (struct inode *inode, struct file *file) {
> printk("skeleton_release\n");
> return 0;
> }
>
> // read function called when from /dev/skeleton is read
> static ssize_t skeleton_read (struct file *file, char *buf,
> size_t count, loff_t *ppos) {
> int len, err;
>
> // check if we have data - if not, sleep
> // wake up in interrupt_handler
> while (data_not_ready) {
> interruptible_sleep_on(&skeleton_wait);
> }
> data_not_ready = 1;
> printk("read works fine");
> if( counter <= 0 )
> return 0;
> err = copy_to_user(buf,string,counter);
> if (err != 0)
> return -EFAULT;
> len = counter;
> counter = 0;
> return len;
> }
>
> // write function called when to /dev/skeleton is written
> static ssize_t skeleton_write (struct file *file, const char *buf,
> size_t count, loff_t *ppos) {
> int err;
> printk("write works fine");
> err = copy_from_user(string,buf,count);
> if (err != 0)
> return -EFAULT;
> counter += count;
> return count;
> }
>
> // ioctl - I/O control
> static int skeleton_ioctl(struct inode *inode, struct file *file,
> unsigned int cmd, unsigned long arg) {
> int retval = 0;
> switch ( cmd ) {
> case CASE1:/* for writing data to arg */
> if (copy_from_user(&data, (int *)arg, sizeof(int)))
> return -EFAULT;
> break;
> case CASE2:/* for reading data from arg */
> if (copy_to_user((int *)arg, &data, sizeof(int)))
> return -EFAULT;
> break;
> default:
> retval = -EINVAL;
> }
> return retval;
> }
>
> // interrupt handler
> irqreturn_t interrupt_handler (int irqn, void *dev)
> {
>
> printk("Press a key ");
>
>
> return IRQ_HANDLED;
>
>
> }
>
> // define which file operations are supported
> struct file_operations skeleton_fops = {
> .owner = THIS_MODULE,
>
> .read = skeleton_read,
> .write = skeleton_write,
>
> .ioctl = skeleton_ioctl,
>
> .open = skeleton_open,
>
> .release = skeleton_release,
>
> };
>
> // initialize module (and interrupt)
> static int __init skeleton_init_module (void) {
> int i;
> int ret;
> printk("initializing module\n");
> //free_irq(7,NULL);
> i = register_chrdev (SKELETON_MAJOR, SKELETON_NAME, &skeleton_fops);
> if (i != 0) return - EIO;
> //disable_irq(7);
> ret = request_irq (7, interrupt_handler,0,SKELETON_NAME ,NULL);
first, the flags using the macro which kernel provides is a good idea.
If your flag indicate the SA_SHIRQ,
means your irq share one interrupt line. SO your interrupt handler
must check your interrupt status registers,and interrupt control
registers,make sure it is your hardware interrupt. for the
common,after your handling routine,u should clean the interrupt status
register. and wait next interrupt or disable the interrupt.
> printk("ret=%d\n",ret);
> //enable_irq(7);
> if(ret>=0){
> enable_irq(7);
> // outb_p(0x10, BASEPORT + 2);
> }
> else
> {
> printk("Not Working \n");
> }
> //printk("Generating interrupt \n");
>
> /*outb(0, BASEPORT);
> outb(255, BASEPORT);
> outb(0, BASEPORT);*/
> printk("Interrupt generated. You should see the handler-message\n");
>
> return 0;
> }
>
> // close and cleanup module
> static void __exit skeleton_cleanup_module (void) {
> printk("cleaning up module\n");
> unregister_chrdev (SKELETON_MAJOR, SKELETON_NAME);
> //disable_irq(6);
> //free_irq(6, NULL);
> }
>
> module_init(skeleton_init_module);
> module_exit(skeleton_cleanup_module);
>
> MODULE_LICENSE("GPL");
> ----------------------------------------------------------------------------------------
>
>
> and after insmod ,i get the following error:
> - Hide quoted text -
> [ 1291.259646] initializing module
>> [ 1291.259672] ret=0
>> [ 1291.259679] ------------[ cut here ]------------
>> [ 1291.259682] WARNING: at
>> /build/buildd/linux-2.6.28/
> kernel/irq/manage.c:225 __enable_irq+0x30/0x70()
>> [ 1291.259685] Unbalanced enable for IRQ 7
>> [ 1291.259687] Modules linked in: skeleton(+) hid_bright usbhid
>> rfkill_input
>> i915 drm binfmt_misc ppdev bridge stp bnep lp parport arc4 ecb
>> snd_hda_intel
>> snd_pcm_oss snd_mixer_oss snd_pcm pcmcia snd_seq_dummy b43 snd_seq_oss
>> snd_seq_midi snd_rawmidi mac80211 snd_seq_midi_event cfg80211 iTCO_wdt
>> iTCO_vendor_support snd_seq snd_timer snd_seq_device yenta_socket
>> rsrc_nonstatic ricoh_mmc sdhci_pci sdhci snd pcmcia_core led_class
>> intel_agp
>> agpgart soundcore snd_page_alloc pcspkr input_polldev serio_raw uvcvideo
>> compat_ioctl32 videodev v4l1_compat video output ohci1394 ieee1394 8139too
>> 8139cp mii ssb fbcon tileblit font bitblit softcursor
>> [ 1291.259751] Pid: 4400, comm: insmod Not tainted 2.6.28-11-generic
>> #42-Ubuntu
>> [ 1291.259754] Call Trace:
>> [ 1291.259760] [<c0139ab0>] warn_slowpath+0x60/0x80
>> [ 1291.259765] [<c0181449>] ? register_handler_proc+0x119/0x130
>> [ 1291.259773] [<c02cc3b8>] ? vsnprintf+0x378/0x5c0
>> [ 1291.259778] [<c013a2f9>] ? release_console_sem+0x1c9/0x200
>> [ 1291.259782] [<c017f570>] __enable_irq+0x30/0x70
>> [ 1291.259786] [<c017f5ec>] enable_irq+0x3c/0x60
>> [ 1291.259790] [<f7f9c000>] ? skeleton_init_module+0x0/0x96 [skeleton]
>> [ 1291.259795] [<f7f9c078>] skeleton_init_module+0x78/0x96 [skeleton]
>> [ 1291.259802] [<c010111e>] _stext+0x2e/0x170
>> [ 1291.259807] [<c020c015>] ? sysfs_addrm_finish+0x15/0xf0
>> [ 1291.259811] [<c020b7e3>] ? sysfs_add_one+0x13/0x50
>> [ 1291.259814] [<c020b85f>] ? sysfs_addrm_start+0x3f/0xa0
>> [ 1291.259820] [<c01a908c>] ? __vunmap+0x9c/0xe0
>> [ 1291.259823] [<c01a908c>] ? __vunmap+0x9c/0xe0
>> [ 1291.259832] [<c01a9121>] ? vfree+0x21/0x30
>> [ 1291.259837] [<c0163f3a>] ? load_module+0x103a/0x1040
>> [ 1291.259848] [<c0163fc8>] sys_init_module+0x88/0x1b0
>> [ 1291.259853] [<c01bb5da>] ? sys_close+0x7a/0xc0
>> [ 1291.259857] [<c0103f6b>] sysenter_do_call+0x12/0x2f
>> [ 1291.259865] [<c0500000>] ? relay_hotcpu_callback+0x6d/0xbd
>> [ 1291.259868] ---[ end trace cddcbfa519faa2fe ]---
>> [ 1291.259870] Interrupt generated. You should see the handler-message
>>
>> and the message in the handler doesnt appear.
>> i am unable to get what is the problem and how can this be solved.
>
> --
> ---------------------
> Harinderjit Singh
> Sent from Delhi, DL, India
--
Best Regards
Lin
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