IRQs

[Altera_Forum]

hey everybody, 

is there an easy guide to use IP core's IRQ in uClinux? do I need an interrupt handler or read from a specific location? thanks :)

[Altera_Forum]

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

[Altera_Forum]

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 

[Altera_Forum]

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

[Altera_Forum]

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?

[Altera_Forum]

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

[Altera_Forum]

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:

[Altera_Forum]

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.

[Altera_Forum]

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 :(

[Altera_Forum]

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.