Clean up common SWD stuff.

src/Makefile

@@ -1,6 +1,6 @@
 PROBE_HOST ?= native
 PLATFORM_DIR = platforms/$(PROBE_HOST)
-VPATH += platforms/common $(PLATFORM_DIR)
+VPATH += $(PLATFORM_DIR) platforms/common
 ENABLE_DEBUG ?=
 
 ifneq ($(V), 1)
@@ -53,6 +53,7 @@ SRC =			\
 	stm32l0.c	\
 	stm32l4.c	\
 	swdptap.c	\
+	swdptap_generic.c	\
 	target.c	\
 
 include $(PLATFORM_DIR)/Makefile.inc

src/adiv5_swdp.c

@@ -50,6 +50,16 @@ int adiv5_swdp_scan(void)
 	ADIv5_DP_t *dp = (void*)calloc(1, sizeof(*dp));
 
 	swdptap_init();
+
+	/* Switch from JTAG to SWD mode */
+	swdptap_seq_out(0xFFFF, 16);
+	for(int i = 0; i < 50; i++)
+		swdptap_bit_out(1);
+	swdptap_seq_out(0xE79E, 16); /* 0b0111100111100111 */
+	for(int i = 0; i < 50; i++)
+		swdptap_bit_out(1);
+	swdptap_seq_out(0, 16);
+
 	/* Read the SW-DP IDCODE register to syncronise */
 	/* This could be done with adiv_swdp_low_access(), but this doesn't
 	 * allow the ack to be checked here. */

src/include/swdptap.h

@@ -22,10 +22,14 @@
 #define __SWDPTAP_H
 
 int swdptap_init(void);
-void swdptap_reset(void);
 
+/* Primitive functions */
+bool swdptap_bit_in(void);
+void swdptap_bit_out(bool val);
+
+/* High level functions, provided as weak in swdptap_generic.c */
 uint32_t swdptap_seq_in(int ticks);
-uint8_t swdptap_seq_in_parity(uint32_t *data, int ticks);
+bool swdptap_seq_in_parity(uint32_t *data, int ticks);
 void swdptap_seq_out(uint32_t MS, int ticks);
 void swdptap_seq_out_parity(uint32_t MS, int ticks);
 

src/platforms/common/swdptap.c

@@ -20,24 +20,24 @@
 
 /* This file implements the low-level SW-DP interface. */
 
-#include <stdio.h>
-
 #include "general.h"
-
 #include "swdptap.h"
 
-#include "gdb_packet.h"
+int swdptap_init(void)
+{
+	return 0;
+}
 
 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;
 
+	DEBUG("%s", dir ? "\n-> ":"\n<- ");
+
 	if(dir)
 		SWDIO_MODE_FLOAT();
 	gpio_set(SWCLK_PORT, SWCLK_PIN);
@@ -46,10 +46,12 @@ static void swdptap_turnaround(uint8_t dir)
 		SWDIO_MODE_DRIVE();
 }
 
-static uint8_t swdptap_bit_in(void)
+bool swdptap_bit_in(void)
 {
 	uint16_t ret;
 
+	swdptap_turnaround(1);
+
 	ret = gpio_get(SWDIO_PORT, SWDIO_PIN);
 	gpio_set(SWCLK_PORT, SWCLK_PIN);
 	gpio_clear(SWCLK_PORT, SWCLK_PIN);
@@ -59,95 +61,14 @@ static uint8_t swdptap_bit_in(void)
 	return ret != 0;
 }
 
-static void swdptap_bit_out(uint8_t val)
+void swdptap_bit_out(bool val)
 {
 	DEBUG("%d", val);
 
+	swdptap_turnaround(0);
+
 	gpio_set_val(SWDIO_PORT, SWDIO_PIN, val);
 	gpio_set(SWCLK_PORT, SWCLK_PIN);
 	gpio_clear(SWCLK_PORT, SWCLK_PIN);
 }
 
-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);
-}
-

src/platforms/libftdi/swdptap.c

@@ -29,9 +29,7 @@
 #include "general.h"
 #include "swdptap.h"
 
-static void swdptap_turnaround(uint8_t dir);
+static uint8_t olddir = 0;
-static uint8_t swdptap_bit_in(void);
-static void swdptap_bit_out(uint8_t val);
 
 int swdptap_init(void)
 {
@@ -46,33 +44,17 @@ int swdptap_init(void)
 	}
 
 	assert(ftdi_write_data(ftdic, (void*)"\xAB\xA8", 2) == 2);
-
+	olddir = 0;
-	/* This must be investigated in more detail.
-	 * As described in STM32 Reference Manual... */
-	swdptap_seq_out(0xFFFF, 16);
-	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);
-}
-
 static void swdptap_turnaround(uint8_t dir)
 {
-	static uint8_t olddir = 0;
-
 	platform_buffer_flush();
 
-	if(dir == olddir) return;
+	if (dir == olddir)
+		return;
 	olddir = dir;
 
 	if(dir)	/* SWDIO goes to input */
@@ -85,10 +67,12 @@ static void swdptap_turnaround(uint8_t dir)
 		assert(ftdi_set_bitmode(ftdic, 0xAB, BITMODE_BITBANG) == 0);
 }
 
-static uint8_t swdptap_bit_in(void)
+bool swdptap_bit_in(void)
 {
 	uint8_t ret;
 
+	swdptap_turnaround(1);
+
 	ftdi_read_pins(ftdic, &ret);
 	ret &= 0x08;
 	ftdi_write_data(ftdic, (void *)"\xA1\xA0", 2);
@@ -96,75 +80,16 @@ static uint8_t swdptap_bit_in(void)
 	return ret;
 }
 
-static void swdptap_bit_out(uint8_t val)
+void swdptap_bit_out(bool val)
 {
 	uint8_t buf[3] = "\xA0\xA1\xA0";
 
-	if(val) {
+	swdptap_turnaround(0);
+
+	if (val) {
 		for(int i = 0; i < 3; i++)
 			buf[i] |= 0x08;
 	}
 	platform_buffer_write(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);
-}
-

src/platforms/tm4c/swdptap.c

@@ -1,124 +0,0 @@
-#include "general.h"
-#include "swdptap.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;
-
-	if(dir)
-		SWDIO_MODE_FLOAT();
-	gpio_set(SWCLK_PORT, SWCLK_PIN);
-	gpio_clear(SWCLK_PORT, SWCLK_PIN);
-	if(!dir)
-		SWDIO_MODE_DRIVE();
-}
-
-static uint8_t swdptap_bit_in(void)
-{
-	uint16_t ret;
-
-	ret = gpio_get(SWDIO_PORT, SWDIO_PIN);
-	gpio_set(SWCLK_PORT, SWCLK_PIN);
-	gpio_clear(SWCLK_PORT, SWCLK_PIN);
-
-	DEBUG("%d", ret?1:0);
-
-	return ret != 0;
-}
-
-static void swdptap_bit_out(uint8_t val)
-{
-	DEBUG("%d", val);
-
-	gpio_set_val(SWDIO_PORT, SWDIO_PIN, val);
-	gpio_set(SWCLK_PORT, SWCLK_PIN);
-	gpio_clear(SWCLK_PORT, SWCLK_PIN);
-}
-
-int
-swdptap_init(void)
-{
-	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);
-}

src/swdptap_generic.c

@@ -0,0 +1,79 @@
+/*
+ * This file is part of the Black Magic Debug project.
+ *
+ * Copyright (C) 2016  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/>.
+ */
+#include "general.h"
+#include "swdptap.h"
+
+uint32_t __attribute__((weak))
+swdptap_seq_in(int ticks)
+{
+	uint32_t index = 1;
+	uint32_t ret = 0;
+
+	while (ticks--) {
+		if (swdptap_bit_in())
+			ret |= index;
+		index <<= 1;
+	}
+
+	return ret;
+}
+
+bool __attribute__((weak))
+swdptap_seq_in_parity(uint32_t *ret, int ticks)
+{
+	uint32_t index = 1;
+	uint8_t parity = 0;
+	*ret = 0;
+
+	while (ticks--) {
+		if (swdptap_bit_in()) {
+			*ret |= index;
+			parity ^= 1;
+		}
+		index <<= 1;
+	}
+	if (swdptap_bit_in())
+		parity ^= 1;
+
+	return parity;
+}
+
+void __attribute__((weak))
+swdptap_seq_out(uint32_t MS, int ticks)
+{
+	while (ticks--) {
+		swdptap_bit_out(MS & 1);
+		MS >>= 1;
+	}
+}
+
+void __attribute__((weak))
+swdptap_seq_out_parity(uint32_t MS, int ticks)
+{
+	uint8_t parity = 0;
+
+	while (ticks--) {
+		swdptap_bit_out(MS & 1);
+		parity ^= MS;
+		MS >>= 1;
+	}
+	swdptap_bit_out(parity & 1);
+}
+