293 lines
6.7 KiB
C
293 lines
6.7 KiB
C
/***************************************************************************
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* Copyright (C) 2008 by Øyvind Harboe *
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* oyvind.harboe@zylin.com *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License for more details. *
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* *
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* You should have received a copy of the GNU General Public License *
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* along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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***************************************************************************/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "replacements.h"
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#include "jtag.h"
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#include "bitbang.h"
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/* my private tap controller state, which tracks state for calling code */
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static tap_state_t dummy_state = TAP_RESET;
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static int dummy_clock; /* edge detector */
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static int clock_count; /* count clocks in any stable state, only stable states */
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static tap_state_t tap_state_transition(tap_state_t cur_state, int tms);
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static u32 dummy_data;
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int dummy_speed(int speed);
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int dummy_register_commands(struct command_context_s *cmd_ctx);
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int dummy_init(void);
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int dummy_quit(void);
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static int dummy_khz(int khz, int *jtag_speed);
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static int dummy_speed_div(int speed, int *khz);
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/* The dummy driver is used to easily check the code path
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* where the target is unresponsive.
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*/
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jtag_interface_t dummy_interface =
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{
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.name = "dummy",
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.execute_queue = bitbang_execute_queue,
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.speed = dummy_speed,
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.register_commands = dummy_register_commands,
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.khz = dummy_khz,
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.speed_div = dummy_speed_div,
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.init = dummy_init,
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.quit = dummy_quit,
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};
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int dummy_read(void);
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void dummy_write(int tck, int tms, int tdi);
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void dummy_reset(int trst, int srst);
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void dummy_led(int on);
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bitbang_interface_t dummy_bitbang =
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{
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.read = dummy_read,
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.write = dummy_write,
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.reset = dummy_reset,
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.blink = dummy_led
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};
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int dummy_read(void)
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{
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int data = 1 & dummy_data;
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dummy_data = (dummy_data >> 1) | (1<<31);
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return data;
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}
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void dummy_write(int tck, int tms, int tdi)
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{
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/* TAP standard: "state transitions occur on rising edge of clock" */
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if( tck != dummy_clock )
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{
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if( tck )
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{
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int old_state = dummy_state;
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dummy_state = tap_state_transition( old_state, tms );
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if( old_state != dummy_state )
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{
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if( clock_count )
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{
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LOG_DEBUG("dummy_tap: %d stable clocks", clock_count);
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clock_count = 0;
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}
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LOG_DEBUG("dummy_tap: %s", jtag_state_name(dummy_state) );
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#if defined(DEBUG)
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if(dummy_state == TAP_DRCAPTURE)
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dummy_data = 0x01255043;
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#endif
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}
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else
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{
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/* this is a stable state clock edge, no change of state here,
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* simply increment clock_count for subsequent logging
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*/
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++clock_count;
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}
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}
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dummy_clock = tck;
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}
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}
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void dummy_reset(int trst, int srst)
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{
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dummy_clock = 0;
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if (trst || (srst && (jtag_reset_config & RESET_SRST_PULLS_TRST)))
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dummy_state = TAP_RESET;
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LOG_DEBUG("reset to: %s", jtag_state_name(dummy_state) );
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}
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static int dummy_khz(int khz, int *jtag_speed)
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{
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if (khz==0)
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{
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*jtag_speed=0;
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}
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else
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{
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*jtag_speed=64000/khz;
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}
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return ERROR_OK;
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}
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static int dummy_speed_div(int speed, int *khz)
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{
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if (speed==0)
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{
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*khz = 0;
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}
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else
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{
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*khz=64000/speed;
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}
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return ERROR_OK;
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}
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int dummy_speed(int speed)
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{
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return ERROR_OK;
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}
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int dummy_register_commands(struct command_context_s *cmd_ctx)
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{
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return ERROR_OK;
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}
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int dummy_init(void)
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{
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bitbang_interface = &dummy_bitbang;
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return ERROR_OK;
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}
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int dummy_quit(void)
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{
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return ERROR_OK;
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}
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void dummy_led(int on)
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{
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}
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/**
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* Function tap_state_transition
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* takes a current TAP state and returns the next state according to the tms value.
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*
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* Even though there is code to duplicate this elsewhere, we do it here a little
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* differently just to get a second opinion, i.e. a verification, on state tracking
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* in that other logic. Plus array lookups without index checking are no favorite thing.
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* This is educational for developers new to TAP controllers.
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*/
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static tap_state_t tap_state_transition(tap_state_t cur_state, int tms)
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{
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tap_state_t new_state;
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if (tms)
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{
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switch (cur_state)
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{
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case TAP_RESET:
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new_state = cur_state;
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break;
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case TAP_IDLE:
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case TAP_DRUPDATE:
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case TAP_IRUPDATE:
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new_state = TAP_DRSELECT;
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break;
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case TAP_DRSELECT:
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new_state = TAP_IRSELECT;
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break;
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case TAP_DRCAPTURE:
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case TAP_DRSHIFT:
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new_state = TAP_DREXIT1;
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break;
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case TAP_DREXIT1:
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case TAP_DREXIT2:
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new_state = TAP_DRUPDATE;
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break;
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case TAP_DRPAUSE:
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new_state = TAP_DREXIT2;
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break;
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case TAP_IRSELECT:
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new_state = TAP_RESET;
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break;
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case TAP_IRCAPTURE:
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case TAP_IRSHIFT:
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new_state = TAP_IREXIT1;
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break;
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case TAP_IREXIT1:
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case TAP_IREXIT2:
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new_state = TAP_IRUPDATE;
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break;
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case TAP_IRPAUSE:
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new_state = TAP_IREXIT2;
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break;
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default:
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LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );
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exit(1);
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break;
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}
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}
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else
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{
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switch (cur_state)
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{
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case TAP_RESET:
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case TAP_IDLE:
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case TAP_DRUPDATE:
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case TAP_IRUPDATE:
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new_state = TAP_IDLE;
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break;
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case TAP_DRSELECT:
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new_state = TAP_DRCAPTURE;
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break;
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case TAP_DRCAPTURE:
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case TAP_DRSHIFT:
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case TAP_DREXIT2:
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new_state = TAP_DRSHIFT;
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break;
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case TAP_DREXIT1:
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case TAP_DRPAUSE:
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new_state = TAP_DRPAUSE;
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break;
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case TAP_IRSELECT:
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new_state = TAP_IRCAPTURE;
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break;
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case TAP_IRCAPTURE:
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case TAP_IRSHIFT:
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case TAP_IREXIT2:
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new_state = TAP_IRSHIFT;
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break;
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case TAP_IREXIT1:
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case TAP_IRPAUSE:
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new_state = TAP_IRPAUSE;
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break;
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default:
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LOG_ERROR( "fatal: invalid argument cur_state=%d", cur_state );
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exit(1);
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break;
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}
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}
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return new_state;
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}
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