RES: Serial device access with qemu!

Jeferson Luiz Rodrigues Souza jeferodrigues at gmail.com
Wed Nov 24 02:58:38 CST 2010


Dear Joel and Wendell,

Thank you for your help. I applied all procedures provided and now I  can
read/write to/from host serial port.

Best regards,
Jeferson.

On Tue, Nov 23, 2010 at 6:32 PM, Joel Sherrill <joel.sherrill at oarcorp.com>wrote:

> Hi,
>
> I have attached a diff to 4.9 which will make the pc386 install
> tty_drv.h.  There is also a diff to the fileio sample to show
> the configuration changes.  Plus a png to show that the
> serial devices are there.
>
> Hopefully this will help.
>
> --joel
>
>
> On 11/23/2010 12:12 PM, Wendell Pereira da Silva wrote:
>
>>
>> Jeferson,
>>
>> Try to incriese the number of termio file descriptors:
>>
>> #define CONFIGURE_NUMBER_OF_TERMIOS_PORTS 6
>>
>> Regards,
>>
>> Wendell.
>>
>> ------------------------------------------------------------------------
>>
>> *De:*rtems-users-bounces at rtems.org [mailto:rtems-users-bounces at rtems.org]
>> *Em nome de *Jeferson Luiz Rodrigues Souza
>> *Enviada em:* terça-feira, 23 de novembro de 2010 13:25
>> *Para:* Joel Sherrill
>> *Cc:* rtems-users at rtems.org
>> *Assunto:* Re: Serial device access with qemu!
>>
>> Dear Joel,
>>
>> On Tue, Nov 23, 2010 at 2:21 PM, Joel Sherrill <joel.sherrill at oarcorp.com<mailto:
>> joel.sherrill at oarcorp.com>> wrote:
>>
>> On 11/23/2010 02:50 AM, Jeferson Luiz Rodrigues Souza wrote:
>>
>> Hi everyone,
>>
>> I am trying to access a serial port in RTEMS 4.9.4 using a pc586 bsp.
>> However, when I execute the application using qemu the code cannot open the
>> device, and the perror() function presents the following message: "No such
>> file or directory". It seems that RTEMS did not initialize a properly driver
>> to handle serial device. Is it right?
>>
>> The qemu command line is:
>>
>> sudo qemu -serial "/dev/ttyS0" -fda floppy.img -boot a
>>
>> I made a search in this list and I found references about serial port
>> access but nothing to help in my case. Could anyone help me or point me some
>> documentation about serial port access in RTEMS?
>>
>> The code used in the test is presented below. I do not have some
>> experience with RTEMS and I do not know the source of this problem.
>>
>> The /dev/ttyS0 above is the host serial port.  The -serial says
>> attach attach the serial port COM1 on the target simulator
>> PC to the specified device.  So you are attaching the virtual
>> COM1 to the real serial port on the host /dev/ttyS0. Is that
>> what you intend to do?
>>
>> FWIW COM1 --> /dev/ttyS1
>> COM2 --> /dev/ttyS2
>>
>> on the RTEMS target.
>>
>>
>> I need to read some data from a device connected in the host serial port
>> (e.g. /dev/ttyS0) inside an application running in RTEMS with qemu.  So, is
>> my source code correct? or Do I need some extra configuration?
>>
>> Where is the name of serial devices in RTEMS defined? I tried use the
>> open() function as follows:
>>
>>  int serial_fp = open("/dev/ttyS0",O_RDONLY);
>> or
>>  int serial_fp = open("/dev/ttyS1",O_RDONLY);
>> or
>>  int serial_fp = open("COM1",O_RDONLY);
>>
>> and got the same message when I checked the serial_fp value and print the
>> error message using perror() function: "No such file or directory"
>>
>> Thanks to reply,
>>
>> Best regards,
>> Jeferson.
>>
>>    --joel
>>
>>        Thanks,
>>        jefecomp.
>>
>>
>>        #include <signal.h>
>>        #include <stdlib.h>
>>        #include <stdio.h>
>>        #include <pthread.h>
>>        #include <uart.h>
>>        #include <termios.h>
>>        #include<sched.h>
>>        #include <bsp.h>
>>        #include <fcntl.h>
>>        #include <sys/types.h>
>>        #include <sys/stat.h>
>>
>>        #define CONFIGURE_INIT
>>        #include <rtems.h>
>>
>>
>>        void *POSIX_Init();
>>
>>        #define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
>>        #define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
>>        #define CONFIGURE_APPLICATIONS_NEEDS_RTC_DRIVER
>>        #define CONFIGURE_MICROSECONDS_PER_TICK 1000
>>
>>        #define CONFIGURE_MAXIMUM_POSIX_THREADS 10
>>        #define CONFIGURE_MAXIMUM_POSIX_CONDITION_VARIABLES 10
>>        #define CONFIGURE_MAXIMUM_POSIX_MUTEXES 10
>>        #define CONFIGURE_MAXIMUM_POSIX_SEMAPHORES 10
>>        #define CONFIGURE_MAXIMUM_POSIX_TIMERS 10
>>        #define CONFIGURE_MAXIMUM_POSIX_QUEUED_SIGNALS 40
>>        #define CONFIGURE_MAXIMUM_POSIX_MESSAGE_QUEUES 10
>>        #define CONFIGURE_POSIX_INIT_THREAD_TABLE
>>        #define CONFIGURE_LIBIO_MAXIMUM_FILE_DESCRIPTORS 5
>>        #define CONFIGURE_NUMBER_OF_TERMIOS_PORTS 3
>>        #include<rtems/confdefs.h>
>>
>>        void *POSIX_Init()
>>        {
>>           printf("Serial Port Test!!!\n");
>>
>>           char buffer[255];
>>           int bytesRead;
>>           int serial_fp = open("/dev/ttyS0",O_RDONLY);
>>
>>           printf("SERIAL_FP = %i\n",serial_fp);
>>
>>           if(serial_fp < 0)
>>           {
>>               printf("FAILURE TO OPEN SERIAL PORT\n");
>>               perror(serial_fp);
>>               exit(-1);
>>           }
>>
>>           //write(serial_fp,buffer,strlen(buffer)+1);
>>           bytesRead = read(serial_fp, buffer, 255);
>>
>>
>>           if(bytesRead < 0)
>>           {
>>               printf("Problems in the read of Serial Port");
>>               close(serial_fp);
>>               exit(1);
>>           }
>>           else
>>               buffer[bytesRead] = 0;
>>
>>
>>           printf(buffer);
>>
>>           close(serial_fp);
>>           exit(0);
>>        }
>>
>>    --     Joel Sherrill, Ph.D.             Director of Research&
>>  Development
>>    joel.sherrill at OARcorp.com        On-Line Applications Research
>>    Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>>      Support Available             (256) 722-9985
>>
>>
>
> --
> Joel Sherrill, Ph.D.             Director of Research&  Development
> joel.sherrill at OARcorp.com        On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
>   Support Available             (256) 722-9985
>
>
>
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