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Diffstat (limited to 'src/platforms/dev2/swdptap.c')
-rw-r--r--src/platforms/dev2/swdptap.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/src/platforms/dev2/swdptap.c b/src/platforms/dev2/swdptap.c
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+++ b/src/platforms/dev2/swdptap.c
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+/*
+ * This file is part of the Black Magic Debug project.
+ *
+ * Copyright (C) 2011 Black Sphere Technologies Ltd.
+ * Written by Gareth McMullin <gareth@blacksphere.co.nz>
+ *
+ * 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 <http://www.gnu.org/licenses/>.
+ */
+
+/* This file implements the low-level SW-DP interface. */
+
+#include <stdio.h>
+
+#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);
+}
+