From e3f8db54e67b503011f624db490964dba9399597 Mon Sep 17 00:00:00 2001
From: Christoph Pittracher <pitt@segfault.info>
Date: Thu, 4 Jun 2015 09:25:10 +0200
Subject: [PATCH] bcm2835gpio: Add SWD support, Raspberry Pi 2 support.

Added support for SWD transport similar to sysfsgpio driver.
Added configurable peripheral base address to support Raspberry Pi 2.

Change-Id: If76d45fbe74ce49f1f22af72e5f246e973237e04
Signed-off-by: Christoph Pittracher <pitt@segfault.info>
Reviewed-on: http://openocd.zylin.com/2802
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
---
 src/jtag/drivers/bcm2835gpio.c        | 167 ++++++++++++++++++++++++--
 tcl/interface/raspberrypi-native.cfg  |   2 +
 tcl/interface/raspberrypi2-native.cfg |  42 +++++++
 3 files changed, 202 insertions(+), 9 deletions(-)
 create mode 100644 tcl/interface/raspberrypi2-native.cfg

diff --git a/src/jtag/drivers/bcm2835gpio.c b/src/jtag/drivers/bcm2835gpio.c
index a2ba8e642..1d84cbe40 100644
--- a/src/jtag/drivers/bcm2835gpio.c
+++ b/src/jtag/drivers/bcm2835gpio.c
@@ -30,10 +30,10 @@
 
 #include <sys/mman.h>
 
-#define BCM2835_PERI_BASE	0x20000000
-#define BCM2835_GPIO_BASE	(BCM2835_PERI_BASE + 0x200000) /* GPIO controller */
+uint32_t bcm2835_peri_base = 0x20000000;
+#define BCM2835_GPIO_BASE	(bcm2835_peri_base + 0x200000) /* GPIO controller */
 
-#define BCM2835_PADS_GPIO_0_27		(BCM2835_PERI_BASE + 0x100000)
+#define BCM2835_PADS_GPIO_0_27		(bcm2835_peri_base + 0x100000)
 #define BCM2835_PADS_GPIO_0_27_OFFSET	(0x2c / 4)
 
 /* GPIO setup macros */
@@ -55,6 +55,9 @@ static int bcm2835gpio_read(void);
 static void bcm2835gpio_write(int tck, int tms, int tdi);
 static void bcm2835gpio_reset(int trst, int srst);
 
+static int bcm2835_swdio_read(void);
+static void bcm2835_swdio_drive(bool is_output);
+
 static int bcm2835gpio_init(void);
 static int bcm2835gpio_quit(void);
 
@@ -62,6 +65,8 @@ static struct bitbang_interface bcm2835gpio_bitbang = {
 	.read = bcm2835gpio_read,
 	.write = bcm2835gpio_write,
 	.reset = bcm2835gpio_reset,
+	.swdio_read = bcm2835_swdio_read,
+	.swdio_drive = bcm2835_swdio_drive,
 	.blink = NULL
 };
 
@@ -78,6 +83,10 @@ static int trst_gpio = -1;
 static int trst_gpio_mode;
 static int srst_gpio = -1;
 static int srst_gpio_mode;
+static int swclk_gpio = -1;
+static int swclk_gpio_mode;
+static int swdio_gpio = -1;
+static int swdio_gpio_mode;
 
 /* Transition delay coefficients */
 static int speed_coeff = 113714;
@@ -101,6 +110,18 @@ static void bcm2835gpio_write(int tck, int tms, int tdi)
 		asm volatile ("");
 }
 
+static void bcm2835gpio_swd_write(int tck, int tms, int tdi)
+{
+	uint32_t set = tck<<swclk_gpio | tdi<<swdio_gpio;
+	uint32_t clear = !tck<<swclk_gpio | !tdi<<swdio_gpio;
+
+	GPIO_SET = set;
+	GPIO_CLR = clear;
+
+	for (unsigned int i = 0; i < jtag_delay; i++)
+		asm volatile ("");
+}
+
 /* (1) assert or (0) deassert reset lines */
 static void bcm2835gpio_reset(int trst, int srst)
 {
@@ -121,6 +142,19 @@ static void bcm2835gpio_reset(int trst, int srst)
 	GPIO_CLR = clear;
 }
 
+static void bcm2835_swdio_drive(bool is_output)
+{
+	if (is_output)
+		OUT_GPIO(swdio_gpio);
+	else
+		INP_GPIO(swdio_gpio);
+}
+
+static int bcm2835_swdio_read(void)
+{
+	return !!(GPIO_LEV & 1 << swdio_gpio);
+}
+
 static int bcm2835gpio_khz(int khz, int *jtag_speed)
 {
 	if (!khz) {
@@ -222,6 +256,40 @@ COMMAND_HANDLER(bcm2835gpio_handle_jtag_gpionum_trst)
 	return ERROR_OK;
 }
 
+COMMAND_HANDLER(bcm2835gpio_handle_swd_gpionums)
+{
+	if (CMD_ARGC == 2) {
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], swdio_gpio);
+	} else if (CMD_ARGC != 0) {
+		return ERROR_COMMAND_SYNTAX_ERROR;
+	}
+
+	command_print(CMD_CTX,
+			"BCM2835 GPIO nums: swclk = %d, swdio = %d",
+			swclk_gpio, swdio_gpio);
+
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(bcm2835gpio_handle_swd_gpionum_swclk)
+{
+	if (CMD_ARGC == 1)
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
+
+	command_print(CMD_CTX, "BCM2835 num: swclk = %d", swclk_gpio);
+	return ERROR_OK;
+}
+
+COMMAND_HANDLER(bcm2835gpio_handle_swd_gpionum_swdio)
+{
+	if (CMD_ARGC == 1)
+		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swdio_gpio);
+
+	command_print(CMD_CTX, "BCM2835 num: swdio = %d", swdio_gpio);
+	return ERROR_OK;
+}
+
 COMMAND_HANDLER(bcm2835gpio_handle_speed_coeffs)
 {
 	if (CMD_ARGC == 2) {
@@ -231,6 +299,13 @@ COMMAND_HANDLER(bcm2835gpio_handle_speed_coeffs)
 	return ERROR_OK;
 }
 
+COMMAND_HANDLER(bcm2835gpio_handle_peripheral_base)
+{
+	if (CMD_ARGC == 1)
+		COMMAND_PARSE_NUMBER(u32, CMD_ARGV[0], bcm2835_peri_base);
+	return ERROR_OK;
+}
+
 static const struct command_registration bcm2835gpio_command_handlers[] = {
 	{
 		.name = "bcm2835gpio_jtag_nums",
@@ -263,6 +338,25 @@ static const struct command_registration bcm2835gpio_command_handlers[] = {
 		.mode = COMMAND_CONFIG,
 		.help = "gpio number for tdi.",
 	},
+	{
+		.name = "bcm2835gpio_swd_nums",
+		.handler = &bcm2835gpio_handle_swd_gpionums,
+		.mode = COMMAND_CONFIG,
+		.help = "gpio numbers for swclk, swdio. (in that order)",
+		.usage = "(swclk swdio)* ",
+	},
+	{
+		.name = "bcm2835gpio_swclk_num",
+		.handler = &bcm2835gpio_handle_swd_gpionum_swclk,
+		.mode = COMMAND_CONFIG,
+		.help = "gpio number for swclk.",
+	},
+	{
+		.name = "bcm2835gpio_swdio_num",
+		.handler = &bcm2835gpio_handle_swd_gpionum_swdio,
+		.mode = COMMAND_CONFIG,
+		.help = "gpio number for swdio.",
+	},
 	{
 		.name = "bcm2835gpio_srst_num",
 		.handler = &bcm2835gpio_handle_jtag_gpionum_srst,
@@ -281,14 +375,24 @@ static const struct command_registration bcm2835gpio_command_handlers[] = {
 		.mode = COMMAND_CONFIG,
 		.help = "SPEED_COEFF and SPEED_OFFSET for delay calculations.",
 	},
+	{
+		.name = "bcm2835gpio_peripheral_base",
+		.handler = &bcm2835gpio_handle_peripheral_base,
+		.mode = COMMAND_CONFIG,
+		.help = "peripheral base to access GPIOs (RPi1 0x20000000, RPi2 0x3F000000).",
+	},
+
 	COMMAND_REGISTRATION_DONE
 };
 
+static const char * const bcm2835_transports[] = { "jtag", "swd", NULL };
+
 struct jtag_interface bcm2835gpio_interface = {
 	.name = "bcm2835gpio",
 	.supported = DEBUG_CAP_TMS_SEQ,
 	.execute_queue = bitbang_execute_queue,
-	.transports = jtag_only,
+	.transports = bcm2835_transports,
+	.swd = &bitbang_swd,
 	.speed = bcm2835gpio_speed,
 	.khz = bcm2835gpio_khz,
 	.speed_div = bcm2835gpio_speed_div,
@@ -297,15 +401,49 @@ struct jtag_interface bcm2835gpio_interface = {
 	.quit = bcm2835gpio_quit,
 };
 
+static bool bcm2835gpio_jtag_mode_possible(void)
+{
+	if (!is_gpio_valid(tck_gpio))
+		return 0;
+	if (!is_gpio_valid(tms_gpio))
+		return 0;
+	if (!is_gpio_valid(tdi_gpio))
+		return 0;
+	if (!is_gpio_valid(tdo_gpio))
+		return 0;
+	return 1;
+}
+
+static bool bcm2835gpio_swd_mode_possible(void)
+{
+	if (!is_gpio_valid(swclk_gpio))
+		return 0;
+	if (!is_gpio_valid(swdio_gpio))
+		return 0;
+	return 1;
+}
+
 static int bcm2835gpio_init(void)
 {
 	bitbang_interface = &bcm2835gpio_bitbang;
 
-	if (!is_gpio_valid(tdo_gpio) || !is_gpio_valid(tdi_gpio) ||
-		!is_gpio_valid(tck_gpio) || !is_gpio_valid(tms_gpio) ||
-		(trst_gpio != -1 && !is_gpio_valid(trst_gpio)) ||
-		(srst_gpio != -1 && !is_gpio_valid(srst_gpio)))
+	LOG_INFO("BCM2835 GPIO JTAG/SWD bitbang driver");
+
+	if (bcm2835gpio_jtag_mode_possible()) {
+		if (bcm2835gpio_swd_mode_possible())
+			LOG_INFO("JTAG and SWD modes enabled");
+		else
+			LOG_INFO("JTAG only mode enabled (specify swclk and swdio gpio to add SWD mode)");
+		if (!is_gpio_valid(trst_gpio) && !is_gpio_valid(srst_gpio)) {
+			LOG_ERROR("Require at least one of trst or srst gpios to be specified");
+			return ERROR_JTAG_INIT_FAILED;
+		}
+	} else if (bcm2835gpio_swd_mode_possible()) {
+		LOG_INFO("SWD only mode enabled (specify tck, tms, tdi and tdo gpios to add JTAG mode)");
+	} else {
+		LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode and/or swclk and swdio gpio for SWD mode");
 		return ERROR_JTAG_INIT_FAILED;
+	}
 
 	dev_mem_fd = open("/dev/mem", O_RDWR | O_SYNC);
 	if (dev_mem_fd < 0) {
@@ -339,18 +477,22 @@ static int bcm2835gpio_init(void)
 	tdi_gpio_mode = MODE_GPIO(tdi_gpio);
 	tck_gpio_mode = MODE_GPIO(tck_gpio);
 	tms_gpio_mode = MODE_GPIO(tms_gpio);
+	swclk_gpio_mode = MODE_GPIO(swclk_gpio);
+	swdio_gpio_mode = MODE_GPIO(swdio_gpio);
 	/*
 	 * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
 	 * as outputs.  Drive TDI and TCK low, and TMS/TRST/SRST high.
 	 */
 	INP_GPIO(tdo_gpio);
 
-	GPIO_CLR = 1<<tdi_gpio | 1<<tck_gpio;
+	GPIO_CLR = 1<<tdi_gpio | 1<<tck_gpio | 1<<swdio_gpio | 1<<swclk_gpio;
 	GPIO_SET = 1<<tms_gpio;
 
 	OUT_GPIO(tdi_gpio);
 	OUT_GPIO(tck_gpio);
 	OUT_GPIO(tms_gpio);
+	OUT_GPIO(swclk_gpio);
+	OUT_GPIO(swdio_gpio);
 	if (trst_gpio != -1) {
 		trst_gpio_mode = MODE_GPIO(trst_gpio);
 		GPIO_SET = 1 << trst_gpio;
@@ -366,6 +508,11 @@ static int bcm2835gpio_init(void)
 		  "tdo %d trst %d srst %d", tck_gpio_mode, tms_gpio_mode,
 		  tdi_gpio_mode, tdo_gpio_mode, trst_gpio_mode, srst_gpio_mode);
 
+	if (swd_mode) {
+		bcm2835gpio_bitbang.write = bcm2835gpio_swd_write;
+		bitbang_switch_to_swd();
+	}
+
 	return ERROR_OK;
 }
 
@@ -375,6 +522,8 @@ static int bcm2835gpio_quit(void)
 	SET_MODE_GPIO(tdi_gpio, tdi_gpio_mode);
 	SET_MODE_GPIO(tck_gpio, tck_gpio_mode);
 	SET_MODE_GPIO(tms_gpio, tms_gpio_mode);
+	SET_MODE_GPIO(swclk_gpio, swclk_gpio_mode);
+	SET_MODE_GPIO(swdio_gpio, swdio_gpio_mode);
 	if (trst_gpio != -1)
 		SET_MODE_GPIO(trst_gpio, trst_gpio_mode);
 	if (srst_gpio != -1)
diff --git a/tcl/interface/raspberrypi-native.cfg b/tcl/interface/raspberrypi-native.cfg
index 058d80bfd..6b73f3541 100644
--- a/tcl/interface/raspberrypi-native.cfg
+++ b/tcl/interface/raspberrypi-native.cfg
@@ -10,6 +10,8 @@
 
 interface bcm2835gpio
 
+bcm2835gpio_peripheral_base 0x20000000
+
 # Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
 # These depend on system clock, calibrated for stock 700MHz
 # bcm2835gpio_speed SPEED_COEFF SPEED_OFFSET
diff --git a/tcl/interface/raspberrypi2-native.cfg b/tcl/interface/raspberrypi2-native.cfg
new file mode 100644
index 000000000..f846fa25d
--- /dev/null
+++ b/tcl/interface/raspberrypi2-native.cfg
@@ -0,0 +1,42 @@
+#
+# Config for using Raspberry Pi's expansion header
+#
+# This is best used with a fast enough buffer but also
+# is suitable for direct connection if the target voltage
+# matches RPi's 3.3V and the cable is short enough.
+#
+# Do not forget the GND connection, pin 6 of the expansion header.
+#
+
+interface bcm2835gpio
+
+bcm2835gpio_peripheral_base 0x3F000000
+
+# Transition delay calculation: SPEED_COEFF/khz - SPEED_OFFSET
+# These depend on system clock, calibrated for stock 700MHz
+# bcm2835gpio_speed SPEED_COEFF SPEED_OFFSET
+bcm2835gpio_speed_coeffs 146203 36
+
+# Each of the JTAG lines need a gpio number set: tck tms tdi tdo
+# Header pin numbers: 23 22 19 21
+# bcm2835gpio_jtag_nums 11 25 10 9
+
+# or if you have both connected,
+# reset_config trst_and_srst srst_push_pull
+
+# Each of the SWD lines need a gpio number set: swclk swdio
+# Header pin numbers: 22 18
+bcm2835gpio_swd_nums 25 24
+
+# If you define trst or srst, use appropriate reset_config
+# Header pin numbers: TRST - 26, SRST - 18
+
+# bcm2835gpio_trst_num 7
+# reset_config trst_only
+
+bcm2835gpio_srst_num 18
+reset_config srst_only srst_push_pull
+
+# or if you have both connected,
+# reset_config trst_and_srst srst_push_pull
+