Need help adding platform UIO devices to board

Need help adding platform UIO devices to board

[Alexander Varnin]

Hello!
I'm trying to add UIO device to my system to handle interrupt. But i'm
facing following problem. Docs says, on reading device /dev/uio0 it will
block until interrupt occurs. I've made simple program for test. It
tries to write 1 to enable interrupts.

    #include <unistd.h>
    #include <errno.h>
    #include <fcntl.h>
    #include <stdio.h>

    int main()
    {
        int fd;
        char c = 1;
        fd = open("/dev/uio0", O_RDONLY);
        if (fd<0) {
            printf("open error: %d\n", errno);
             return 0;
        }
        printf("fd == %d\n", fd);
        int res = write(fd, &c, 1);
        if(res<0) {
            printf("write error: %d\n", errno);
        }
        return 0;
    }

And as the output i get

    fd ==
    3                                                                        

    write error: 9 

error 9 means "bad file descriptor". File /dev/uio0 is here.
/sys/class/uio/uio0 folder i also. Reading are fails the same way.

Here is how i add device to the system in board specific code

    static struct uio_info cross_uio_info = {
       .name = "uio_mcross",
       .version = "0.1",
       .irq = IRQ_EINT14,
       .irq_flags = 0,
    };

    static struct platform_device minipos_cross_device = {
        .name          = "uio_pdrv_genirq",
        .id          = -1,
        .dev              = {
          .platform_data = &cross_uio_info,
        }
    };

and then add platform device.
Please, help.

Re: Need help adding platform UIO devices to board

[Nicholas Mc Guire]

On Wed, 28 Nov 2012, Alexander Varnin wrote:

> Hello!
> I'm trying to add UIO device to my system to handle interrupt. But i'm
> facing following problem. Docs says, on reading device /dev/uio0 it will
> block until interrupt occurs. I've made simple program for test. It
> tries to write 1 to enable interrupts.
> 
>     #include <unistd.h>
>     #include <errno.h>
>     #include <fcntl.h>
>     #include <stdio.h>
> 
>     int main()
>     {
>         int fd;
>         char c = 1;
>         fd = open("/dev/uio0", O_RDONLY);
>         if (fd<0) {
>             printf("open error: %d\n", errno);
>              return 0;
>         }
>         printf("fd == %d\n", fd);
>         int res = write(fd, &c, 1);
>         if(res<0) {
>             printf("write error: %d\n", errno);
>         }
>         return 0;
>     }
>
open O_RDONLY and then write to it ?

return of 9 == EBADF

man 2 write

 EBADF  fd is not a valid file descriptor or is not open for writing.

hofrat 

Re: Need help adding platform UIO devices to board

[Alexander Varnin]

28.11.2012 23:03, Nicholas Mc Guire пишет:
> open O_RDONLY and then write to it ?
>
> return of 9 == EBADF
>
> man 2 write
>
>   EBADF  fd is not a valid file descriptor or is not open for writing.
>
> hofrat
Yes, sorry, stupid mistake.
But with the correct rights O_RDWR i get error 22 EINVAL both on read 
and write.
So problem is still there.

Re: Need help adding platform UIO devices to board

[Alexander Varnin]

Where to add printk?

29.11.2012 12:45, 游競雄 пишет:
> Did you add printk to understand what happened?
>
> BR

Re: Need help adding platform UIO devices to board

[Alexander Varnin]

29.11.2012 13:29, Alexander Varnin пишет:
> 28.11.2012 23:03, Nicholas Mc Guire пишет:
> Yes, sorry, stupid mistake.
> But with the correct rights O_RDWR i get error 22 EINVAL both on read 
> and write.
> So problem is still there.
> -- 
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Seems to be solved.

Problem was due to lines

if (count != sizeof(s32))
return -EINVAL;

in uio_read kernel function.

I've made read of 4 bytes, and it is ok.