326 lines
9.5 KiB
C
326 lines
9.5 KiB
C
/***************************************************************************
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* Copyright (C) 2005 by Dominic Rath *
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* Dominic.Rath@gmx.de *
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* *
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* Copyright (C) 2007,2008 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 "bitbang.h"
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#include "interface.h"
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#include "commands.h"
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/**
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* Function bitbang_stableclocks
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* issues a number of clock cycles while staying in a stable state.
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* Because the TMS value required to stay in the RESET state is a 1, whereas
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* the TMS value required to stay in any of the other stable states is a 0,
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* this function checks the current stable state to decide on the value of TMS
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* to use.
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*/
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static void bitbang_stableclocks(int num_cycles);
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bitbang_interface_t *bitbang_interface;
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/* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
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*
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* Set this to 1 and str912 reset halt will fail.
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*
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* If someone can submit a patch with an explanation it will be greatly
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* appreciated, but as far as I can tell (ØH) DCLK is generated upon
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* clk = 0 in TAP_IDLE. Good luck deducing that from the ARM documentation!
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* The ARM documentation uses the term "DCLK is asserted while in the TAP_IDLE
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* state". With hardware there is no such thing as *while* in a state. There
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* are only edges. So clk => 0 is in fact a very subtle state transition that
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* happens *while* in the TAP_IDLE state. "#&¤"#¤&"#&"#&
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*
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* For "reset halt" the last thing that happens before srst is asserted
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* is that the breakpoint is set up. If DCLK is not wiggled one last
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* time before the reset, then the breakpoint is not set up and
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* "reset halt" will fail to halt.
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*
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*/
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#define CLOCK_IDLE() 0
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/* The bitbang driver leaves the TCK 0 when in idle */
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static void bitbang_end_state(tap_state_t state)
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{
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if (tap_is_state_stable(state))
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tap_set_end_state(state);
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else
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{
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LOG_ERROR("BUG: %i is not a valid end state", state);
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exit(-1);
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}
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}
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static void bitbang_state_move(int skip)
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{
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int i = 0, tms = 0;
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uint8_t tms_scan = tap_get_tms_path(tap_get_state(), tap_get_end_state());
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int tms_count = tap_get_tms_path_len(tap_get_state(), tap_get_end_state());
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for (i = skip; i < tms_count; i++)
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{
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tms = (tms_scan >> i) & 1;
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bitbang_interface->write(0, tms, 0);
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bitbang_interface->write(1, tms, 0);
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}
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bitbang_interface->write(CLOCK_IDLE(), tms, 0);
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tap_set_state(tap_get_end_state());
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}
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static void bitbang_path_move(pathmove_command_t *cmd)
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{
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int num_states = cmd->num_states;
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int state_count;
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int tms = 0;
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state_count = 0;
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while (num_states)
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{
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if (tap_state_transition(tap_get_state(), false) == cmd->path[state_count])
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{
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tms = 0;
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}
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else if (tap_state_transition(tap_get_state(), true) == cmd->path[state_count])
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{
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tms = 1;
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}
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else
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{
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LOG_ERROR("BUG: %s -> %s isn't a valid TAP transition", tap_state_name(tap_get_state()), tap_state_name(cmd->path[state_count]));
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exit(-1);
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}
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bitbang_interface->write(0, tms, 0);
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bitbang_interface->write(1, tms, 0);
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tap_set_state(cmd->path[state_count]);
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state_count++;
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num_states--;
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}
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bitbang_interface->write(CLOCK_IDLE(), tms, 0);
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tap_set_end_state(tap_get_state());
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}
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static void bitbang_runtest(int num_cycles)
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{
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int i;
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tap_state_t saved_end_state = tap_get_end_state();
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/* only do a state_move when we're not already in IDLE */
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if (tap_get_state() != TAP_IDLE)
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{
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bitbang_end_state(TAP_IDLE);
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bitbang_state_move(0);
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}
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/* execute num_cycles */
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for (i = 0; i < num_cycles; i++)
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{
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bitbang_interface->write(0, 0, 0);
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bitbang_interface->write(1, 0, 0);
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}
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bitbang_interface->write(CLOCK_IDLE(), 0, 0);
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/* finish in end_state */
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bitbang_end_state(saved_end_state);
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if (tap_get_state() != tap_get_end_state())
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bitbang_state_move(0);
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}
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static void bitbang_stableclocks(int num_cycles)
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{
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int tms = (tap_get_state() == TAP_RESET ? 1 : 0);
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int i;
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/* send num_cycles clocks onto the cable */
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for (i = 0; i < num_cycles; i++)
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{
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bitbang_interface->write(1, tms, 0);
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bitbang_interface->write(0, tms, 0);
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}
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}
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static void bitbang_scan(bool ir_scan, enum scan_type type, uint8_t *buffer, int scan_size)
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{
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tap_state_t saved_end_state = tap_get_end_state();
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int bit_cnt;
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if (!((!ir_scan && (tap_get_state() == TAP_DRSHIFT)) || (ir_scan && (tap_get_state() == TAP_IRSHIFT))))
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{
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if (ir_scan)
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bitbang_end_state(TAP_IRSHIFT);
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else
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bitbang_end_state(TAP_DRSHIFT);
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bitbang_state_move(0);
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bitbang_end_state(saved_end_state);
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}
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for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++)
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{
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int val = 0;
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int tms = (bit_cnt == scan_size-1) ? 1 : 0;
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int tdi;
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int bytec = bit_cnt/8;
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int bcval = 1 << (bit_cnt % 8);
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/* if we're just reading the scan, but don't care about the output
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* default to outputting 'low', this also makes valgrind traces more readable,
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* as it removes the dependency on an uninitialised value
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*/
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tdi = 0;
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if ((type != SCAN_IN) && (buffer[bytec] & bcval))
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tdi = 1;
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bitbang_interface->write(0, tms, tdi);
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if (type != SCAN_OUT)
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val = bitbang_interface->read();
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bitbang_interface->write(1, tms, tdi);
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if (type != SCAN_OUT)
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{
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if (val)
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buffer[bytec] |= bcval;
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else
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buffer[bytec] &= ~bcval;
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}
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}
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if (tap_get_state() != tap_get_end_state())
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{
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/* we *KNOW* the above loop transitioned out of
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* the shift state, so we skip the first state
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* and move directly to the end state.
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*/
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bitbang_state_move(1);
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}
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}
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int bitbang_execute_queue(void)
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{
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jtag_command_t *cmd = jtag_command_queue; /* currently processed command */
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int scan_size;
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enum scan_type type;
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uint8_t *buffer;
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int retval;
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if (!bitbang_interface)
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{
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LOG_ERROR("BUG: Bitbang interface called, but not yet initialized");
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exit(-1);
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}
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/* return ERROR_OK, unless a jtag_read_buffer returns a failed check
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* that wasn't handled by a caller-provided error handler
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*/
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retval = ERROR_OK;
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if (bitbang_interface->blink)
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bitbang_interface->blink(1);
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while (cmd)
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{
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switch (cmd->type)
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{
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case JTAG_RESET:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst);
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#endif
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if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_get_reset_config() & RESET_SRST_PULLS_TRST)))
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{
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tap_set_state(TAP_RESET);
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}
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bitbang_interface->reset(cmd->cmd.reset->trst, cmd->cmd.reset->srst);
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break;
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case JTAG_RUNTEST:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("runtest %i cycles, end in %s", cmd->cmd.runtest->num_cycles, tap_state_name(cmd->cmd.runtest->end_state));
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#endif
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bitbang_end_state(cmd->cmd.runtest->end_state);
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bitbang_runtest(cmd->cmd.runtest->num_cycles);
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break;
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case JTAG_STABLECLOCKS:
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/* this is only allowed while in a stable state. A check for a stable
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* state was done in jtag_add_clocks()
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*/
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bitbang_stableclocks(cmd->cmd.stableclocks->num_cycles);
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break;
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case JTAG_STATEMOVE:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("statemove end in %s", tap_state_name(cmd->cmd.statemove->end_state));
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#endif
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bitbang_end_state(cmd->cmd.statemove->end_state);
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bitbang_state_move(0);
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break;
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case JTAG_PATHMOVE:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("pathmove: %i states, end in %s", cmd->cmd.pathmove->num_states,
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tap_state_name(cmd->cmd.pathmove->path[cmd->cmd.pathmove->num_states - 1]));
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#endif
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bitbang_path_move(cmd->cmd.pathmove);
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break;
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case JTAG_SCAN:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("%s scan end in %s", (cmd->cmd.scan->ir_scan) ? "IR" : "DR", tap_state_name(cmd->cmd.scan->end_state));
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#endif
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bitbang_end_state(cmd->cmd.scan->end_state);
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scan_size = jtag_build_buffer(cmd->cmd.scan, &buffer);
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type = jtag_scan_type(cmd->cmd.scan);
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bitbang_scan(cmd->cmd.scan->ir_scan, type, buffer, scan_size);
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if (jtag_read_buffer(buffer, cmd->cmd.scan) != ERROR_OK)
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retval = ERROR_JTAG_QUEUE_FAILED;
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if (buffer)
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free(buffer);
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break;
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case JTAG_SLEEP:
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#ifdef _DEBUG_JTAG_IO_
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LOG_DEBUG("sleep %i", cmd->cmd.sleep->us);
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#endif
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jtag_sleep(cmd->cmd.sleep->us);
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break;
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default:
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LOG_ERROR("BUG: unknown JTAG command type encountered");
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exit(-1);
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}
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cmd = cmd->next;
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}
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if (bitbang_interface->blink)
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bitbang_interface->blink(0);
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return retval;
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}
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