src/jtag/drivers/bitbang.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2
   3 /***************************************************************************
   4  *   Copyright (C) 2005 by Dominic Rath                                    *
   5  *   Dominic.Rath@gmx.de                                                   *
   6  *                                                                         *
   7  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   8  *   oyvind.harboe@zylin.com                                               *
   9  ***************************************************************************/
  10
  11 #ifndef OPENOCD_JTAG_DRIVERS_BITBANG_H
  12 #define OPENOCD_JTAG_DRIVERS_BITBANG_H
  13
  14 #include <jtag/swd.h>
  15 #include <jtag/commands.h>
  16
  17 typedef enum {
  18         BB_LOW,
  19         BB_HIGH,
  20         BB_ERROR
  21 } bb_value_t;
  22
  23 /** Low level callbacks (for bitbang).
  24  *
  25  * Either read(), or sample() and read_sample() must be implemented.
  26  *
  27  * The sample functions allow an interface to batch a number of writes and
  28  * sample requests together. Not waiting for a value to come back can greatly
  29  * increase throughput. */
  30 struct bitbang_interface {
  31         /** Sample TDO and return the value. */
  32         bb_value_t (*read)(void);
  33
  34         /** The number of TDO samples that can be buffered up before the caller has
  35          * to call read_sample. */
  36         size_t buf_size;
  37
  38         /** Sample TDO and put the result in a buffer. */
  39         int (*sample)(void);
  40
  41         /** Return the next unread value from the buffer. */
  42         bb_value_t (*read_sample)(void);
  43
  44         /** Set TCK, TMS, and TDI to the given values. */
  45         int (*write)(int tck, int tms, int tdi);
  46
  47         /** Blink led (optional). */
  48         int (*blink)(int on);
  49
  50         /** Sample SWDIO and return the value. */
  51         int (*swdio_read)(void);
  52
  53         /** Set direction of SWDIO. */
  54         void (*swdio_drive)(bool on);
  55
  56         /** Set SWCLK and SWDIO to the given value. */
  57         int (*swd_write)(int swclk, int swdio);
  58
  59         /** Sleep for some number of microseconds. **/
  60         int (*sleep)(unsigned int microseconds);
  61
  62         /** Force a flush. */
  63         int (*flush)(void);
  64 };
  65
  66 extern const struct swd_driver bitbang_swd;
  67
  68 int bitbang_execute_queue(struct jtag_command *cmd_queue);
  69
  70 extern struct bitbang_interface *bitbang_interface;
  71
  72 #endif /* OPENOCD_JTAG_DRIVERS_BITBANG_H */