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Diffstat (limited to 'src/platforms/dev2/swdptap.c')
-rw-r--r--src/platforms/dev2/swdptap.c173
1 files changed, 173 insertions, 0 deletions
diff --git a/src/platforms/dev2/swdptap.c b/src/platforms/dev2/swdptap.c
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index 0000000..2f7c73d
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+++ b/src/platforms/dev2/swdptap.c
@@ -0,0 +1,173 @@
+/*
+ * 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 "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);
+}
+
+
+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;
+}
+
+
+static uint64_t swdptap_seq_in_64(int ticks)
+{
+ int i;
+ uint64_t ret = 0;
+
+ swdptap_turnaround(1);
+
+ uint8_t cmd[] = {
+ DEV2_OP_SERIAL_IN, SWDIO_PIN, SWCLK_PIN, ticks,
+ };
+ platform_buffer_write(cmd, sizeof(cmd));
+ uint8_t rep[8];
+ int bytes = (ticks + 7) / 8;
+ platform_buffer_read(rep, bytes);
+
+ for(i = 0; i < bytes; i++)
+ ret |= (uint64_t) rep[i] << (8 * i);
+
+ DEBUG("(0x%0*" PRIx64 ",%d)", (ticks + 3) / 4, ret, ticks);
+
+ return ret;
+}
+
+
+uint32_t swdptap_seq_in(int ticks)
+{
+ return swdptap_seq_in_64(ticks);
+}
+
+
+uint8_t swdptap_seq_in_parity(uint32_t *ret, int ticks)
+{
+ uint64_t tmp;
+ uint8_t parity = 0;
+ int i;
+
+ tmp = swdptap_seq_in_64(ticks + 1);
+
+ for(i = 0; i < ticks + 1; i++)
+ {
+ if(tmp & (1ull << i))
+ parity ^= 1;
+ }
+
+ *ret = tmp & ((1ull << ticks) - 1);
+ return parity;
+}
+
+
+static void swdptap_seq_out_64(uint64_t MS, int ticks)
+{
+ swdptap_turnaround(0);
+
+ DEBUG("(0x%0*" PRIx64 ",%d)", (ticks + 3) / 4, MS, ticks);
+
+ uint8_t cmd[12];
+ int i = 0;
+ cmd[i++] = DEV2_OP_SERIAL_OUT;
+ cmd[i++] = SWDIO_PIN;
+ cmd[i++] = SWCLK_PIN;
+ cmd[i++] = ticks;
+ for(; ticks > 0; ticks -= 8)
+ {
+ cmd[i++] = MS & 0xff;
+ MS >>= 8;
+ }
+ platform_buffer_write(cmd, i);
+}
+
+
+void swdptap_seq_out(uint32_t MS, int ticks)
+{
+ swdptap_seq_out_64(MS, ticks);
+}
+
+
+void swdptap_seq_out_parity(uint32_t MS, int ticks)
+{
+ uint8_t parity = 0;
+ uint64_t tmp;
+ int i;
+
+ for(i = 0; i < ticks; i++)
+ {
+ if(MS & (1 << i))
+ parity ^= 1;
+ }
+ tmp = MS;
+ if(parity)
+ tmp |= 1ull << ticks;
+
+ swdptap_seq_out_64(tmp, ticks + 1);
+}
+
+
+void swdptap_reset(void)
+{
+ /* 50 clocks with TMS high */
+ swdptap_seq_out_64((1ull << 50) - 1, 50);
+}
+
+