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From: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
To: linux-bluetooth@vger.kernel.org
Cc: Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
Subject: [PATCH BlueZ 3/3] monitor: Add support for reading over J-Link RTT
Date: Thu, 22 Feb 2018 10:20:55 +0100
Message-Id: <20180222092055.22493-4-andrzej.kaczmarek@codecoup.pl>
In-Reply-To: <20180222092055.22493-1-andrzej.kaczmarek@codecoup.pl>
References: <20180222092055.22493-1-andrzej.kaczmarek@codecoup.pl>
Sender: linux-bluetooth-owner@vger.kernel.org
List-ID: <linux-bluetooth.vger.kernel.org>

This patch adds support for reading data over J-Link RTT. It can be
used as replacement for TTY when reading from embedded devices since
it's much faster and does block a UART. Data format is the same as
for TTY. At the moment monitor over RTT is only supported by Apache
Mynewt project.

Reading data is done by polling RTT every 1 msec since there is no
blocking API to read something from RTT buffer.

To enable reading from RTT, J-Link and RTT configuration needs to be
passed via command line:
  -J --jlink <device>,<interface>,<speed>,<serialno>
  -R --rtt <address>,<area>,<buffer>

<device> - one of devices supported by J-Link (no default)
<interface> - only 'swd' supported for now (default: swd)
<speed> - interface speed (default: 1000)
<serialno> - emu serial number or 0 if not used (detault: 0)
<address> - RTT control block address (default: 0)
<area> - RTT control block search area length (default: 0)
<buffer> - RTT buffer name with monitor data stream (default: monitor)

Parameters with default values can be omitted.

For example, to read from default nRF52 device and look for RTT buffer
with default name over entire RAM area use:
  btmon -J nrf52 -R 0x20000000,0x10000
---
 Makefile.tools    |  3 ++-
 monitor/control.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 monitor/control.h |  1 +
 monitor/main.c    | 30 ++++++++++++++++++++++++++----
 4 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/Makefile.tools b/Makefile.tools
index 71d083e71..7466633bb 100644
--- a/Makefile.tools
+++ b/Makefile.tools
@@ -59,9 +59,10 @@ monitor_btmon_SOURCES = monitor/main.c monitor/bt.h \
 				monitor/analyze.h monitor/analyze.c \
 				monitor/intel.h monitor/intel.c \
 				monitor/broadcom.h monitor/broadcom.c \
+				monitor/jlink.h monitor/jlink.c \
 				monitor/tty.h
 monitor_btmon_LDADD = lib/libbluetooth-internal.la \
-				src/libshared-mainloop.la @UDEV_LIBS@
+				src/libshared-mainloop.la @UDEV_LIBS@ -ldl
 endif
 
 if TESTING
diff --git a/monitor/control.c b/monitor/control.c
index 98f414be9..73462be42 100644
--- a/monitor/control.c
+++ b/monitor/control.c
@@ -54,6 +54,7 @@
 #include "ellisys.h"
 #include "tty.h"
 #include "control.h"
+#include "jlink.h"
 
 static struct btsnoop *btsnoop_file = NULL;
 static bool hcidump_fallback = false;
@@ -1376,6 +1377,55 @@ int control_tty(const char *path, unsigned int speed)
 	return 0;
 }
 
+static void rtt_callback(int id, void *user_data)
+{
+	struct control_data *data = user_data;
+	ssize_t len;
+
+	do {
+		len = jlink_rtt_read(data->buf + data->offset,
+					sizeof(data->buf) - data->offset);
+		data->offset += len;
+		process_data(data);
+	} while (len > 0);
+
+	if (mainloop_modify_timeout(id, 1) < 0)
+		mainloop_exit_failure();
+}
+
+int control_rtt(char *jlink, char *rtt)
+{
+	struct control_data *data;
+
+	if (jlink_init() < 0) {
+		fprintf(stderr, "Failed to initialize J-Link library\n");
+		return -EIO;
+	}
+
+	if (jlink_connect(jlink) < 0) {
+		fprintf(stderr, "Failed to connect to target device\n");
+		return -ENODEV;
+	}
+
+	if (jlink_start_rtt(rtt) < 0) {
+		fprintf(stderr, "Failed to initialize RTT\n");
+		return -ENODEV;
+	}
+
+	printf("--- RTT opened ---\n");
+
+	data = new0(struct control_data, 1);
+	data->channel = HCI_CHANNEL_MONITOR;
+	data->fd = -1;
+
+	if (mainloop_add_timeout(1, rtt_callback, data, free_data) < 0) {
+		free(data);
+		return -EIO;
+	}
+
+	return 0;
+}
+
 bool control_writer(const char *path)
 {
 	btsnoop_file = btsnoop_create(path, BTSNOOP_FORMAT_MONITOR);
diff --git a/monitor/control.h b/monitor/control.h
index 630a852e4..c315eb7db 100644
--- a/monitor/control.h
+++ b/monitor/control.h
@@ -28,6 +28,7 @@ bool control_writer(const char *path);
 void control_reader(const char *path);
 void control_server(const char *path);
 int control_tty(const char *path, unsigned int speed);
+int control_rtt(char *jlink, char *rtt);
 int control_tracing(void);
 void control_disable_decoding(void);
 
diff --git a/monitor/main.c b/monitor/main.c
index 3e61a4661..27132e3c3 100644
--- a/monitor/main.c
+++ b/monitor/main.c
@@ -72,6 +72,10 @@ static void usage(void)
 		"\t-S, --sco              Dump SCO traffic\n"
 		"\t-A, --a2dp             Dump A2DP stream traffic\n"
 		"\t-E, --ellisys [ip]     Send Ellisys HCI Injection\n"
+		"\t-R  --rtt <device>,[<interface>],[<speed>],[<serialno>]\n"
+		"\t                       Read data from RTT\n"
+		"\t-C  --rtt-cb [<address>],[<area>],[<name>]\n"
+		"\t                       RTT control block parameters\n"
 		"\t-h, --help             Show help options\n");
 }
 
@@ -89,6 +93,8 @@ static const struct option main_options[] = {
 	{ "sco",     no_argument,	NULL, 'S' },
 	{ "a2dp",    no_argument,	NULL, 'A' },
 	{ "ellisys", required_argument, NULL, 'E' },
+	{ "jlink",   required_argument, NULL, 'J' },
+	{ "rtt",     required_argument, NULL, 'R' },
 	{ "todo",    no_argument,       NULL, '#' },
 	{ "version", no_argument,       NULL, 'v' },
 	{ "help",    no_argument,       NULL, 'h' },
@@ -106,6 +112,8 @@ int main(int argc, char *argv[])
 	unsigned int tty_speed = B115200;
 	unsigned short ellisys_port = 0;
 	const char *str;
+	char *jlink = NULL;
+	char *rtt = NULL;
 	int exit_status;
 	sigset_t mask;
 
@@ -117,7 +125,7 @@ int main(int argc, char *argv[])
 		int opt;
 		struct sockaddr_un addr;
 
-		opt = getopt_long(argc, argv, "d:r:w:a:s:p:i:tTSAE:vh",
+		opt = getopt_long(argc, argv, "d:r:w:a:s:p:i:tTSAE:J:R:vh",
 						main_options, NULL);
 		if (opt < 0)
 			break;
@@ -182,6 +190,12 @@ int main(int argc, char *argv[])
 			ellisys_server = optarg;
 			ellisys_port = 24352;
 			break;
+		case 'J':
+			jlink = optarg;
+			break;
+		case 'R':
+			rtt = optarg;
+			break;
 		case '#':
 			packet_todo();
 			lmp_todo();
@@ -240,11 +254,19 @@ int main(int argc, char *argv[])
 	if (ellisys_server)
 		ellisys_enable(ellisys_server, ellisys_port);
 
-	if (!tty && control_tracing() < 0)
+	if (tty && jlink)
 		return EXIT_FAILURE;
 
-	if (tty && control_tty(tty, tty_speed) < 0)
-		return EXIT_FAILURE;
+	if (tty) {
+		if (control_tty(tty, tty_speed) < 0)
+			return EXIT_FAILURE;
+	} else if (jlink) {
+		if (control_rtt(jlink, rtt) < 0)
+			return EXIT_FAILURE;
+	} else {
+		if (control_tracing() < 0)
+			return EXIT_FAILURE;
+	}
 
 	exit_status = mainloop_run();
 
-- 
2.16.2