Transplantation of Uclinux-2008r1-rc8 (bf561) to VDSP5 (58)

Uclinux-2008r1-rc8 (bf561) to VDSP5 Transplant (MB): Unable to open an initial console blog.

Encountered a depressed problem, prompted "Unable to open a initial console" after no later.

The location where this error occurred is searched, in the Init_post function:

if (sys_open((const char __user *) "/dev/console", O_RDWR, 0) < 0)
　printk(KERN_WARNING "Warning: unable to open an initial console./n");

Just started to think that is not the reason for the correct establishment of/dev/console, but after tracking in to find not so,/dev/console has been correctly created, the problem appears in the Tty_open function.

In this function, it first obtains the tty_driver of the console:

if (device == MKDEV(TTYAUX_MAJOR,1)) {
　driver = console_device(&index);
　if (driver) {
　　/* Don't let /dev/console block */
　　filp->f_flags |= O_NONBLOCK;
　　noctty = 1;
　　goto got_driver;
　}
　mutex_unlock(&tty_mutex);
　return -ENODEV;
}

Look at the implementation of the Console_device:

/*
　* Return the console tty driver structure and its associated index
　*/
struct tty_driver *console_device(int *index)
{
　　　　 struct console *c;
　　　　 struct tty_driver *driver = NULL;

　　　　 acquire_console_sem();
　　　　 for (c = console_drivers; c != NULL; c = c->next) {
　　　　　　　　 if (!c->device)
　　　　　　　　　　　　　 continue;
　　　　　　　　 driver = c->device(c, index);
　　　　　　　　 if (driver)
　　　　　　　　　　　　　 break;
　　　　 }
　　　　 release_console_sem();
　　　　 return driver;
}

It looks for all available console, finds a console that provides Tty_driver, and returns. In the kernel, the actual console used is described by the global variable Bfin_serial_console (DRIVERS/SERIAL/BFIN_5XX.C). The device callback function is provided in this structure to obtain the tty_driver used by this console:

static struct console bfin_serial_console = {
　　　　 .name　　　　　　　　 = BFIN_SERIAL_NAME,
　　　　 .write　　　　　　　 = bfin_serial_console_write,
　　　　 .device　　　　　　 = uart_console_device,
　　　　 .setup　　　　　　　 = bfin_serial_console_setup,
　　　　 .flags　　　　　　　 = CON_PRINTBUFFER,
　　　　 .index　　　　　　　 = -1,
　　　　 .data　　　　　　　　 = &bfin_serial_reg,
};