source: trunk/tools/bootloader_tsar/boot_tty_driver.h @ 1

Last change on this file since 1 was 1, checked in by alain, 5 years ago

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1/****************************************************************************
2 * This file defines a nano-driver for SocLib vci_multi_tty component, used *
3 * by the ALMOS-MKH boot-loader.                                             *
4 *                                                                          *
5 * The SEG_TTY_BASE address must be defined in the 'hard_config.h' file.    *
6 *                                                                          *
7 * All accesses to the device registers are performed via 2 low-level       *
8 * functions 'boot_tty_get_register()' and 'boot_tty_set_register()'.       *
9 ****************************************************************************/
10
11#ifndef BOOT_TTY_DRIVER_H
12#define BOOT_TTY_DRIVER_H
13
14#include <hal_types.h>
15
16/****************************************************************************
17 *                           Driver register map.                           *
18 ****************************************************************************/
19
20enum TTY_registers
21{
22    TTY_WRITE   = 0,    /* character to be displayed on screen              */
23    TTY_STATUS  = 1,    /* read and write buffer status                     */
24    TTY_READ    = 2,    /* character in the keyboard                        */
25    TTY_CONFIG  = 3,    /* unused                                           */
26   
27    TTY_SPAN    = 4,    /* segment size for one channel ( words )           */
28};
29
30/****************************************************************************
31 *                           Driver status value.                           *
32 ****************************************************************************/
33
34enum TTY_status
35{
36    TTY_READ_BUSY   = 1,    /* Set if TTY_READ register contains a data.    */
37    TTY_WRITE_BUSY  = 2,    /* Set if TTY_WRITE register contains a data.   */
38};
39
40/****************************************************************************
41 *                           Driver API functions.                          *
42 ****************************************************************************/
43
44/****************************************************************************
45 * This function writes a character string from the 'buf' buffer to the     *
46 * boot TTY terminal. It tests the TTY_STATUS register before writing each  *
47 * character of the string to the TTY_WRITE register. If TTY_WRITE_BUSY     *
48 * bit is set, it keeps testing the TTY_STATUS register. If after 10000     *
49 * retries the bit is still set, the function reports an error and returns. *
50 * @ buf    : buffer containing the string to be printed                    *
51 * @ nbytes : number of characters to be printed                            *
52 * @ returns 0 on success, -1 on error.                                     *
53 ****************************************************************************/
54int boot_tty_write( char    * buf,
55                    uint32_t  nbytes );
56
57#endif // BOOT_TTY_DRIVER_H
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