src/jtag/drivers/bitbang.h

   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   This program is free software; you can redistribute it and/or modify  *
   9  *   it under the terms of the GNU General Public License as published by  *
  10  *   the Free Software Foundation; either version 2 of the License, or     *
  11  *   (at your option) any later version.                                   *
  12  *                                                                         *
  13  *   This program is distributed in the hope that it will be useful,       *
  14  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  15  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  16  *   GNU General Public License for more details.                          *
  17  *                                                                         *
  18  *   You should have received a copy of the GNU General Public License     *
  19  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  20  ***************************************************************************/
  21
  22 #ifndef OPENOCD_JTAG_DRIVERS_BITBANG_H
  23 #define OPENOCD_JTAG_DRIVERS_BITBANG_H
  24
  25 #include <jtag/swd.h>
  26
  27 typedef enum {
  28         BB_LOW,
  29         BB_HIGH,
  30         BB_ERROR
  31 } bb_value_t;
  32
  33 /** Low level callbacks (for bitbang).
  34  *
  35  * Either read(), or sample() and read_sample() must be implemented.
  36  *
  37  * The sample functions allow an interface to batch a number of writes and
  38  * sample requests together. Not waiting for a value to come back can greatly
  39  * increase throughput. */
  40 struct bitbang_interface {
  41         /** Sample TDO. */
  42         bb_value_t (*read)(void);
  43
  44         /** The number of TDO samples that can be buffered up before the caller has
  45          * to call read_sample. */
  46         size_t buf_size;
  47         /** Sample TDO and put the result in a buffer. */
  48         int (*sample)(void);
  49         /** Return the next unread value from the buffer. */
  50         bb_value_t (*read_sample)(void);
  51
  52         /** Set TCK, TMS, and TDI to the given values. */
  53         int (*write)(int tck, int tms, int tdi);
  54         int (*reset)(int trst, int srst);
  55         int (*blink)(int on);
  56         int (*swdio_read)(void);
  57         void (*swdio_drive)(bool on);
  58 };
  59
  60 const struct swd_driver bitbang_swd;
  61
  62 extern bool swd_mode;
  63
  64 int bitbang_execute_queue(void);
  65
  66 extern struct bitbang_interface *bitbang_interface;
  67 void bitbang_switch_to_swd(void);
  68 int bitbang_swd_switch_seq(enum swd_special_seq seq);
  69
  70 #endif /* OPENOCD_JTAG_DRIVERS_BITBANG_H */