[Xenomai-help] unable to open serial port from a kernel module

[Xenomai-help] unable to open serial port from a kernel module

[Anisha Kaul]

hi,

when i use rt_dev_open ("/dev/ttyS0", 0); from the function init_module () of 
a self written kernel module, it returns -19 ! What must be the reason, can't 
a file be opened from a kernel module ?

kindly help !

-------------------------------------
Hi-Tech Gears Limited, Gurgaon, India

Re: [Xenomai-help] unable to open serial port from a kernel module

[Jan Kiszka]

Anisha Kaul wrote:
> hi,
> 
> when i use rt_dev_open ("/dev/ttyS0", 0); from the function init_module () of 
> a self written kernel module, it returns -19 ! What must be the reason, can't 
> a file be opened from a kernel module ?

Please read documentation and examples more carefully: "rtdev0" is the
answer.

Jan

-- 
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux

Re: [Xenomai-help] unable to open serial port from a kernel module

[Anisha Kaul]

> Anisha Kaul wrote:
> > hi,
> >
> > when i use rt_dev_open ("/dev/ttyS0", 0); from the function init_module
> > () of a self written kernel module, it returns -19 ! What must be the
> > reason, can't a file be opened from a kernel module ?
>
> Please read documentation and examples more carefully: "rtdev0" is the
> answer.
>
> Jan

Thanks for being patient, 

Did you mean this --> ''rtdm_open ("rtdev0", 0);" 
I tried this from the init_module () of the concerned kernel module, it still 
returns '-19'.

Anyways, as per your example '', I tried --> "rt_dev_open  ("rtdev0", 0);" 
from the main () function of the user space program. As per one of your mails 
I added "-lrtdm" to the LDFLAGS of the concerned Makefile for the compilation 
of rt_dev_open. The program compiled without errors but still it 
returns '-19'.

regards,
anisha

-------------------------------------
Hi-Tech Gears Limited, Gurgaon, India

Re: [Xenomai-help] unable to open serial port from a kernel module

[Anisha Kaul]

[-- Attachment #1: Type: text/plain, Size: 615 bytes --]

On Wednesday November 11 2009 14  : 49  : 19 you wrote:
> Anisha Kaul wrote:
> > hi,
> >
> > when i use rt_dev_open ("/dev/ttyS0", 0); from the function init_module
> > () of a self written kernel module, it returns -19 ! What must be the
> > reason, can't a file be opened from a kernel module ?
>
> Please read documentation and examples more carefully: "rtdev0" is the
> answer.
>
> Jan

Hi,

I forgot to attach the kernel module file as well as the user space file in 
the previous mail. Hereby I have included both of them !

kernel module file: serialPortISR.c
user space file   : userSpace.c

thanks,
anisha

[-- Attachment #2: serialPortISR.c --]
[-- Type: text/x-csrc, Size: 1499 bytes --]

#include <native/task.h>
#include <native/heap.h>
#include <native/intr.h>
#include <linux/kernel.h>
#include <rtdm/rtdm_driver.h>

#define PORT 0x3F8

RT_INTR serialRT;
RT_HEAP heap_desc;
rtdm_task_t task;
char*   shmem;

static rtdm_task_t tasklet;

static int times;
rtdm_task_proc_t resetRegisters (void * f)
{
    outb (0x83, PORT + 3);
    outb (0x01, PORT + 0);
    outb (0x00, PORT + 1);
    outb (0x03, PORT + 3);
    outb (0x01, PORT + 1);
    outb (0x27, PORT + 2);
    outb (0x08, PORT + 4);

    return NULL;
}

rt_isr_t isrSerialPort (int irq, void *dev_id, struct pt_regs *regs)
{
    times++;
    printk (KERN_ALERT "\nisrSerialPort called %d ", times);

    *shmem = inb (PORT);

    printk ("\nsharedMem: %s", shmem);

    rtdm_task_init (&tasklet, "tasklet", resetRegisters, NULL, 1, 0);
    
    return (rt_isr_t) IRQ_HANDLED;
}

int init_module ()
{
    rt_intr_create (&serialRT, "softbrainISR", 4, isrSerialPort, NULL, I_SHARED);
    rt_intr_enable (&serialRT);

    outb (0x83, PORT + 3);
    outb (0x01, PORT + 0);
    outb (0x00, PORT + 1);
    outb (0x03, PORT + 3);
    outb (0x01, PORT + 1);
    outb (0x27, PORT + 2);
    outb (0x08, PORT + 4);

    rt_heap_create (&heap_desc, "MyHeap", 16384, H_SHARED);
    rt_heap_alloc (&heap_desc, 0, TM_NONBLOCK, (void*)&shmem);

    return result;
}

void cleanup_module ()
{
    rt_heap_free (&heap_desc, &shmem);
    rt_intr_delete (&serialRT);

    printk (KERN_ALERT "\ncleanup_module called\n");
}

MODULE_LICENSE ("GPL");

[-- Attachment #3: userSpace.c --]
[-- Type: text/x-csrc, Size: 570 bytes --]

#include <sys/mman.h>
#include <native/task.h>
#include <native/timer.h>
#include <native/heap.h>
#include <string.h>
#include <rtdm/rtdm.h>

RT_TASK task_desc;
RT_HEAP heap_desc;
void*   shmem;

int main ()
{
    mlockall (MCL_CURRENT|MCL_FUTURE);

    rt_heap_bind  (&heap_desc, "MyHeap", TM_NONBLOCK);
    rt_heap_alloc (&heap_desc, 1, TM_NONBLOCK, &shmem);

/***************************************/
    int result = rt_dev_open  ("rtdev0", 0);

    printf ("\n%d passed ", result);

    rt_dev_write (result, "abcd", 4);
/***************************************/
}

[-- Attachment #4: Type: text/plain, Size: 79 bytes --]



-------------------------------------
Hi-Tech Gears Limited, Gurgaon, India

Re: [Xenomai-help] unable to open serial port from a kernel module

[Stefan Kisdaroczi]

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Hi,

> int main ()
> {
>     mlockall (MCL_CURRENT|MCL_FUTURE);

you need to call rt_task_shadow(...) here (see docs),
which turns the current Linux task into a native Xenomai task.

>     rt_heap_bind  (&heap_desc, "MyHeap", TM_NONBLOCK);
>     rt_heap_alloc (&heap_desc, 1, TM_NONBLOCK, &shmem);

check all return values. I guess its -19 too without rt_task_shadow.

> /***************************************/
>     int result = rt_dev_open  ("rtdev0", 0);
> 
>     printf ("\n%d passed ", result);
> 
>     rt_dev_write (result, "abcd", 4);
> /***************************************/
> }

good luck,
kisda


Anisha Kaul schrieb:
> On Wednesday November 11 2009 14  : 49  : 19 you wrote:
>> Anisha Kaul wrote:
>>> hi,
>>>
>>> when i use rt_dev_open ("/dev/ttyS0", 0); from the function init_module
>>> () of a self written kernel module, it returns -19 ! What must be the
>>> reason, can't a file be opened from a kernel module ?
>> Please read documentation and examples more carefully: "rtdev0" is the
>> answer.
>>
>> Jan
> 
> Hi,
> 
> I forgot to attach the kernel module file as well as the user space file in 
> the previous mail. Hereby I have included both of them !
> 
> kernel module file: serialPortISR.c
> user space file   : userSpace.c
> 
> thanks,
> anisha
> 
> 
> ------------------------------------------------------------------------
> 
> 
> 
> -------------------------------------
> Hi-Tech Gears Limited, Gurgaon, India
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help



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