X-Git-Url: https://review.openocd.org/gitweb?a=blobdiff_plain;f=src%2Fjtag%2Fbitbang.c;h=24346712a8d66cf4af238621e7d1d6e28c9a8670;hb=68c598e88d5e09728ea845a81ab279c615bbaf0f;hp=054faf503be0f5fff3cccb2fdf083733682d9323;hpb=d47e1b8f362379d8a2307f49e2b42115a3f40524;p=openocd.git diff --git a/src/jtag/bitbang.c b/src/jtag/bitbang.c index 054faf503b..24346712a8 100644 --- a/src/jtag/bitbang.c +++ b/src/jtag/bitbang.c @@ -2,6 +2,9 @@ * Copyright (C) 2005 by Dominic Rath * * Dominic.Rath@gmx.de * * * + * Copyright (C) 2007,2008 Øyvind Harboe * + * oyvind.harboe@zylin.com * + * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * @@ -34,16 +37,33 @@ #include #include -#include -#include - bitbang_interface_t *bitbang_interface; + +/* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work! + * + * Set this to 1 and str912 reset halt will fail. + * + * If someone can submit a patch with an explanation it will be greatly + * appreciated, but as far as I can tell (ØH) DCLK is generated upon + * clk=0 in TAP_RTI. Good luck deducing that from the ARM documentation! + * The ARM documentation uses the term "DCLK is asserted while in the TAP_RTI + * state". With hardware there is no such thing as *while* in a state. There + * are only edges. So clk => 0 is in fact a very subtle state transition that + * happens *while* in the TAP_RTI state. "#&¤"#¤&"#&"#& + * + * For "reset halt" the last thing that happens before srst is asserted + * is that the breakpoint is set up. If DCLK is not wiggled one last + * time before the reset, then the breakpoint is not set up and + * "reset halt" will fail to halt. + * + */ +#define CLOCK_IDLE() 0 + int bitbang_execute_queue(void); /* The bitbang driver leaves the TCK 0 when in idle */ - void bitbang_end_state(enum tap_state state) { if (tap_move_map[state] != -1) @@ -66,7 +86,7 @@ void bitbang_state_move(void) { bitbang_interface->write(0, tms, 0); bitbang_interface->write(1, tms, 0); } - bitbang_interface->write(0, tms, 0); + bitbang_interface->write(CLOCK_IDLE(), tms, 0); cur_state = end_state; } @@ -75,7 +95,7 @@ void bitbang_path_move(pathmove_command_t *cmd) { int num_states = cmd->num_states; int state_count; - int tms; + int tms = 0; state_count = 0; while (num_states) @@ -102,7 +122,7 @@ void bitbang_path_move(pathmove_command_t *cmd) num_states--; } - bitbang_interface->write(0, tms, 0); + bitbang_interface->write(CLOCK_IDLE(), tms, 0); end_state = cur_state; } @@ -121,12 +141,12 @@ void bitbang_runtest(int num_cycles) } /* execute num_cycles */ - bitbang_interface->write(0, 0, 0); for (i = 0; i < num_cycles; i++) { - bitbang_interface->write(1, 0, 0); bitbang_interface->write(0, 0, 0); + bitbang_interface->write(1, 0, 0); } + bitbang_interface->write(CLOCK_IDLE(), 0, 0); /* finish in end_state */ bitbang_end_state(saved_end_state); @@ -138,7 +158,6 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size) { enum tap_state saved_end_state = end_state; int bit_cnt; - int last_bit, last_bit_in; if (!((!ir_scan && (cur_state == TAP_SD)) || (ir_scan && (cur_state == TAP_SI)))) { @@ -151,7 +170,7 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size) bitbang_end_state(saved_end_state); } - for (bit_cnt = 0; bit_cnt < scan_size - 1; bit_cnt++) + for (bit_cnt = 0; bit_cnt < scan_size; bit_cnt++) { /* if we're just reading the scan, but don't care about the output * default to outputting 'low', this also makes valgrind traces more readable, @@ -159,69 +178,48 @@ void bitbang_scan(int ir_scan, enum scan_type type, u8 *buffer, int scan_size) */ if ((type != SCAN_IN) && ((buffer[bit_cnt/8] >> (bit_cnt % 8)) & 0x1)) { - bitbang_interface->write(0, 0, 1); - bitbang_interface->write(1, 0, 1); + bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 1); + bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 1); } else { - bitbang_interface->write(0, 0, 0); - bitbang_interface->write(1, 0, 0); + bitbang_interface->write(0, (bit_cnt==scan_size-1) ? 1 : 0, 0); + bitbang_interface->write(1, (bit_cnt==scan_size-1) ? 1 : 0, 0); } if (type != SCAN_OUT) { + /* + TDO should be sampled on the rising edge, and will change + on the falling edge. + + Because there is no way to read the signal exactly at the rising edge, + read after the rising edge. + + This is plain IEEE 1149 JTAG - nothing specific to the OpenOCD or its JTAG + API. + */ if (bitbang_interface->read()) buffer[(bit_cnt)/8] |= 1 << ((bit_cnt) % 8); else buffer[(bit_cnt)/8] &= ~(1 << ((bit_cnt) % 8)); } } - - if ((type != SCAN_IN) && ((buffer[bit_cnt/8] >> (bit_cnt % 8)) & 0x1)) - last_bit = 1; - else - last_bit = 0; - - if ((ir_scan && (end_state == TAP_SI)) || - (!ir_scan && (end_state == TAP_SD))) - { - bitbang_interface->write(0, 0, last_bit); - bitbang_interface->write(1, 0, last_bit); - - if (type != SCAN_OUT) - last_bit_in = bitbang_interface->read(); - - bitbang_interface->write(0, 0, last_bit); - } + + /* TAP_SD & TAP_SI are illegal end states, so we always transition to the pause + * state which is a legal stable state from which statemove will work. + * + * Exit1 -> Pause + */ + bitbang_interface->write(0, 0, 0); + bitbang_interface->write(1, 0, 0); + bitbang_interface->write(CLOCK_IDLE(), 0, 0); + + if (ir_scan) + cur_state = TAP_PI; else - { - /* Shift-[ID]R -> Exit1-[ID]R */ - bitbang_interface->write(0, 1, last_bit); - bitbang_interface->write(1, 1, last_bit); - - if (type != SCAN_OUT) - last_bit_in = bitbang_interface->read(); - - /* Exit1-[ID]R -> Pause-[ID]R */ - bitbang_interface->write(0, 0, 0); - bitbang_interface->write(1, 0, 0); - - if (cur_state == TAP_SI) - cur_state = TAP_PI; - else - cur_state = TAP_PD; - - if (cur_state != end_state) - bitbang_state_move(); - else - bitbang_interface->write(0, 0, 0); - } - - if (type != SCAN_OUT) - { - if (last_bit_in) - buffer[(bit_cnt)/8] |= 1 << ((bit_cnt) % 8); - else - buffer[(bit_cnt)/8] &= ~(1 << ((bit_cnt) % 8)); - } + cur_state = TAP_PD; + + if (cur_state != end_state) + bitbang_state_move(); } int bitbang_execute_queue(void) @@ -261,7 +259,7 @@ int bitbang_execute_queue(void) #ifdef _DEBUG_JTAG_IO_ LOG_DEBUG("reset trst: %i srst %i", cmd->cmd.reset->trst, cmd->cmd.reset->srst); #endif - if (cmd->cmd.reset->trst == 1) + if ((cmd->cmd.reset->trst == 1) || (cmd->cmd.reset->srst && (jtag_reset_config & RESET_SRST_PULLS_TRST))) { cur_state = TAP_TLR; }