/* * This file is part of the Black Magic Debug project. * * Copyright (C) 2011 Black Sphere Technologies Ltd. * Written by Gareth McMullin * * 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 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see . */ /* This file implements the low-level SW-DP interface. */ #include #include "general.h" #include "swdptap.h" #include "gdb_packet.h" static void swdptap_turnaround(uint8_t dir) { static uint8_t olddir = 0; DEBUG("%s", dir ? "\n-> ":"\n<- "); /* Don't turnaround if direction not changing */ if(dir == olddir) return; olddir = dir; uint8_t cmd[6]; int i = 0; if(dir) { cmd[i++] = DEV2_OP_DIR_IN; cmd[i++] = SWDIO_PIN; } cmd[i++] = DEV2_OP_OUT_SET; cmd[i++] = SWCLK_PIN; cmd[i++] = DEV2_OP_OUT_RESET; cmd[i++] = SWCLK_PIN; if(!dir) { cmd[i++] = DEV2_OP_DIR_OUT; cmd[i++] = SWDIO_PIN; } platform_buffer_write(cmd, i); } static uint8_t swdptap_bit_in(void) { uint8_t cmd[] = { DEV2_OP_IN, DEV2_OP_OUT_SET, SWCLK_PIN, DEV2_OP_OUT_RESET, SWCLK_PIN, }; platform_buffer_write (cmd, sizeof (cmd)); uint8_t rep[1]; platform_buffer_read (rep, sizeof (rep)); int ret = rep[0] & SWDIO_PIN; DEBUG("%d", ret?1:0); return ret != 0; } static void swdptap_bit_out(uint8_t val) { DEBUG("%d", val); uint8_t cmd[] = { DEV2_OP_OUT_CHANGE, SWDIO_PIN, (val ? SWDIO_PIN : 0), DEV2_OP_OUT_SET, SWCLK_PIN, DEV2_OP_OUT_RESET, SWCLK_PIN, }; platform_buffer_write (cmd, sizeof (cmd)); } int swdptap_init(void) { /* This must be investigated in more detail. * As described in STM32 Reference Manual... */ swdptap_reset(); swdptap_seq_out(0xE79E, 16); /* 0b0111100111100111 */ swdptap_reset(); swdptap_seq_out(0, 16); return 0; } void swdptap_reset(void) { swdptap_turnaround(0); /* 50 clocks with TMS high */ for(int i = 0; i < 50; i++) swdptap_bit_out(1); } uint32_t swdptap_seq_in(int ticks) { uint32_t index = 1; uint32_t ret = 0; swdptap_turnaround(1); while(ticks--) { if(swdptap_bit_in()) ret |= index; index <<= 1; } return ret; } uint8_t swdptap_seq_in_parity(uint32_t *ret, int ticks) { uint32_t index = 1; uint8_t parity = 0; *ret = 0; swdptap_turnaround(1); while(ticks--) { if(swdptap_bit_in()) { *ret |= index; parity ^= 1; } index <<= 1; } if(swdptap_bit_in()) parity ^= 1; return parity; } void swdptap_seq_out(uint32_t MS, int ticks) { swdptap_turnaround(0); while(ticks--) { swdptap_bit_out(MS & 1); MS >>= 1; } } void swdptap_seq_out_parity(uint32_t MS, int ticks) { uint8_t parity = 0; swdptap_turnaround(0); while(ticks--) { swdptap_bit_out(MS & 1); parity ^= MS; MS >>= 1; } swdptap_bit_out(parity & 1); }