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Diffstat (limited to 'src/core/console.c')
-rw-r--r-- | src/core/console.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/src/core/console.c b/src/core/console.c new file mode 100644 index 00000000..6e92cb54 --- /dev/null +++ b/src/core/console.c @@ -0,0 +1,102 @@ +/* + * Central console switch. Various console devices can be selected + * via the build options CONSOLE_FIRMWARE, CONSOLE_SERIAL etc. + * config.c picks up on these definitions and drags in the relevant + * objects. The linker compiles the console_drivers table for us; we + * simply delegate to each console_driver that we find in the table. + * + * Doing it this way allows for changing CONSOLE_XXX without + * rebuilding anything other than config.o. This is extremely useful + * for rom-o-matic. + */ + +#include "stddef.h" +#include "console.h" + +/* FIXME: we need a cleaner way to pick up cpu_nap(). It makes a + * real-mode call, and so we don't want to use it with LinuxBIOS. + */ +#include "bios.h" + +extern struct console_driver console_drivers[]; +extern struct console_driver console_drivers_end[]; + +/***************************************************************************** + * putchar : write a single character to each console + ***************************************************************************** + */ + +void putchar ( int character ) { + struct console_driver *console; + + /* Automatic LF -> CR,LF translation */ + if ( character == '\n' ) + putchar ( '\r' ); + + for ( console = console_drivers; console < console_drivers_end ; + console++ ) { + if ( ( ! console->disabled ) && console->putchar ) + console->putchar ( character ); + } +} + +/***************************************************************************** + * has_input : check to see if any input is available on any console, + * and return a pointer to the console device if so + ***************************************************************************** + */ +static struct console_driver * has_input ( void ) { + struct console_driver *console; + + for ( console = console_drivers; console < console_drivers_end ; + console++ ) { + if ( ( ! console->disabled ) && console->iskey ) { + if ( console->iskey () ) + return console; + } + } + return NULL; +} + +/***************************************************************************** + * getchar : read a single character from any console + * + * NOTE : this function does not echo the character, and it does block + ***************************************************************************** + */ + +int getchar ( void ) { + struct console_driver *console; + int character = 256; + + while ( character == 256 ) { + /* Doze for a while (until the next interrupt). This works + * fine, because the keyboard is interrupt-driven, and the + * timer interrupt (approx. every 50msec) takes care of the + * serial port, which is read by polling. This reduces the + * power dissipation of a modern CPU considerably, and also + * makes Etherboot waiting for user interaction waste a lot + * less CPU time in a VMware session. + */ + cpu_nap(); + + console = has_input(); + if ( console && console->getchar ) + character = console->getchar (); + } + + /* CR -> LF translation */ + if ( character == '\r' ) + character = '\n'; + + return character; +} + +/***************************************************************************** + * iskey : check to see if any input is available on any console + ***************************************************************************** + */ + +int iskey ( void ) { + return has_input() ? 1 : 0; +} |