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-rw-r--r--src/linux/swdptap.c182
1 files changed, 182 insertions, 0 deletions
diff --git a/src/linux/swdptap.c b/src/linux/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/>.
+ */
+
+/* Quick hack for bit-banging SW-DP interface over FT2232.
+ * Intended as proof of concept, not for production.
+ */
+
+#include <stdio.h>
+#include <assert.h>
+#include <ftdi.h>
+
+#include "platform.h"
+#include "swdptap.h"
+
+static struct ftdi_context ftdic;
+static int f;
+
+#define BUF_SIZE 4096
+
+int swdptap_init(void)
+{
+ ftdi_init(&ftdic);
+ ftdi_set_interface(&ftdic, INTERFACE_A);
+ f = ftdi_usb_open(&ftdic, FT2232_VID, FT2232_PID);
+ if(f < 0 && f != -5) {
+ fprintf(stderr, "unable to open ftdi device: %d (%s)\n",
+ f, ftdi_get_error_string(&ftdic));
+ return -1;
+ }
+ printf("ftdi open succeeded(channel 1): %d\n",f);
+
+ ftdi_set_latency_timer(&ftdic, 1);
+ ftdi_set_baudrate(&ftdic, 10000000);
+ ftdi_usb_purge_buffers(&ftdic);
+
+ printf("enabling bitbang mode(channel 1)\n");
+ assert(ftdi_set_bitmode(&ftdic, 0xAB, BITMODE_BITBANG) == 0);
+ //assert(ftdi_write_data(&ftdic, "\x86\x00\x00\x80\xA8\xAB", 6) == 6);
+ ftdi_write_data(&ftdic, "\xAB\xA8", 2);
+ ftdi_write_data_set_chunksize(&ftdic, BUF_SIZE);
+
+ /* 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);
+}
+
+void swdptap_turnaround(uint8_t dir)
+{
+ static uint8_t olddir = 0;
+
+ DEBUG("%s", dir ? "\n-> ":"\n<- ");
+
+ if(dir == olddir) return;
+ olddir = dir;
+
+ if(dir) /* SWDIO goes to input */
+ assert(ftdi_set_bitmode(&ftdic, 0xA3, BITMODE_BITBANG) == 0);
+
+ /* One clock cycle */
+ ftdi_write_data(&ftdic, "\xAB\xA8", 2);
+
+ if(!dir) /* SWDIO goes to output */
+ assert(ftdi_set_bitmode(&ftdic, 0xAB, BITMODE_BITBANG) == 0);
+}
+
+uint8_t swdptap_bit_in(void)
+{
+ uint8_t ret;
+
+ //ftdi_read_data(&ftdic, &ret, 1);
+ ftdi_read_pins(&ftdic, &ret);
+ //ret &= 0x08;
+ ftdi_write_data(&ftdic, "\xA1\xA0", 2);
+
+ DEBUG("%x\n", ret);
+
+ return ret & 0x08;
+}
+
+void swdptap_bit_out(uint8_t val)
+{
+ uint8_t buf[3] = "\xA0\xA1\xA0";
+
+ DEBUG("%d", val);
+
+ if(val) {
+ for(int i = 0; i < 3; i++)
+ buf[i] |= 0x08;
+ }
+ ftdi_write_data(&ftdic, buf, 3);
+}
+
+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);
+}
+