IRQs

The normal way to handle IRQs is doing a Kernel driver. As the OS handle the ISR entry and exit for you, here, the C code you do is not different from what is done with other architectures. There are lot of examples in the Kernel sources.

Is that what you want to do ?

I learned that "uio" should allow for a kind of ISR in s user land application, but I never did look into that.

-Michael

I have an IP assigned to IRQ 2,

I tried to get an interrupt through my kernel driver with no luck so far

I thought maybe I missed something, it's my first try with interrupts in uclinux

could you direct me to those code examples?

thanks

Did you read "Linux Device Drivers" 3rd Edition by Rubini and friends ?

Here you learn how to register an ISR with the Kernel and youl be pointed to exeamples.

-Michael

hey Michael,

this is really helpful, thanks

but I have a small problem

when I compile my code it says that SA_SHIRQ is undeclared... same goes for SA_INTERRUPT

any idea why?

The irq header changed a lot since the book published. Please check current kernel header. You may look at some drivers for the usage.

linux-2.6/include/linux/interrupt.h

- Hippo

you're right, it's completly different now

I tried to write the simplest thing I could

in the __init function:

<div class='quotetop'>QUOTE </div>

--- Quote Start ---

/* register interrupt */

if (request_irq(UART_IRQ, uart_pio_isr, IRQF_DISABLED, "uart_pio", (void *)(uart_pio_isr)))

{

printk("uart_pio: unable to register interrupt %d\n", UART_IRQ);

return -1;

}[/b]

--- Quote End ---

above it:

<div class='quotetop'>QUOTE </div>

--- Quote Start ---

static irqreturn_t uart_pio_isr(int irq, void *dev_id, struct pt_regs *regs)

{

int data;

data = inb(UART);

printk("<>Interrupt recieved, ");

printk("data is %d<>\n",data);

return IRQ_HANDLED;

}[/b]

--- Quote End ---

but I still can&#39;t get interrupts... I know it&#39;s not a hw problem

does this warning has something to do with it?

<div class='quotetop'>quote </div>

--- quote start ---

warning: passing argument 2 of &#39;request_irq&#39; from incompatible pointer type

--- Quote End ---

[/b]

thanks :huh:

My ISR function signatures look like this:

static irqreturn_t isr_handler(int irq, void *data)

Yours has one more parameter. That is probably the cause of your warning, but I do not know if that is the root cause.

well that did solve the warning but not the problem

I tried something even simpler than before

I added PIO for switches and enabled it to generate interrupt (edge)

and still, no sign of life

I can read from it and write to a similar PIO module

but no interrupts

is it a code problem?

<div class='quotetop'>QUOTE </div>

--- Quote Start ---

#include </home/atop/nios2-linux/uClinux-dist/linux-2.6.x/include/asm-nios2/nios2.h> /* My system */# include <linux/kernel.h> /* We&#39;re doing kernel work */# include <linux/module.h> /* Specifically, a module */# include <linux/fs.h># include <linux/configfs.h># include <linux/cdev.h># include <linux/interrupt.h> /* Using interrupts (request_irq,free_irq...),(IRQF_SHARED,IRQF_DISABLED...) */# include <linux/init.h> /* For __init and __exit functions */# include <linux/slab.h># include <asm/uaccess.h> /* For copy_from_user and copy_to_user */# include <asm/signal.h> # include <asm/io.h>

# define switches na_Switches# define switches_IRQ na_Switches_irq# define switches_MAJOR 247

static int Device_Open = 0; //indicate whether the device is open

static ssize_t switches_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)

{

char buffer;

buffer = inb(switches);

copy_to_user(buf,&buffer,1);

/* Changing reading position as best suits */

if (*ppos == 0)

{

*ppos+=1;

return 1;

}

else

{

return 0;

}

}

static int switches_open(struct inode *inode, struct file *file)

{

# ifdef DEBUG

printk(KERN_INFO "device_open(%p)\n", file);

# endif

if (Device_Open)

return 1; //return failure

Device_Open++;

try_module_get(THIS_MODULE);

return 0; //return success

}

static int switches_release(struct inode *inode, struct file *file)

{

# ifdef DEBUG

printk(KERN_INFO "device_release(%p,%p)\n", inode, file);

# endif

Device_Open-=1;

module_put(THIS_MODULE);

free_irq(switches_IRQ, NULL);

return 0; //return success

}

static struct file_operations switches_fops =

{

.read = switches_read,

.write = NULL,

.open = switches_open,

.release = switches_release

};

/*********************************INTERRUPT************************************/

static irqreturn_t switches_pio_isr(int irq, void *dev_id)//, struct pt_regs *regs)

{

int data;

printk("<>Interrupt recieved, ");

data = inb(switches);

printk("data is %d<>\n",data);

return IRQ_HANDLED;

}

/******************************************************************************/

static int __init switches_init(void)

{

if(register_chrdev (switches_MAJOR, "switches", &switches_fops))

{

printk("<>could not register switches module... crap<>\n");

}

/* register interrupt */

if (request_irq(switches_IRQ, switches_pio_isr, IRQF_DISABLED, "switches", NULL))

{

printk("switches_pio: unable to register interrupt %d\n", switches_IRQ);

return -1;

}

printk("<>switches module registered... yey<>\n");

return 0;

}

static void __exit switches_exit(void)

{

unregister_chrdev(switches_MAJOR, "switches");

printk("<>switches module unloaded<>\n");

}

module_init (switches_init);

module_exit (switches_exit);

MODULE_LICENSE("GPL");

MODULE_DESCRIPTION("switches...");

MODULE_AUTHOR("Asaf B.");[/b]

--- Quote End ---

I know I&#39;m probably being annoying but I really haven&#39;t got a clue what&#39;s wrong :(

Hi,

I think that I am with a similar problem that you have or you have had. Do you solve it?? If you have solved it can you explain which was the problem??

Thanks a lot.