drivers: xds110: Add support TCK changes in firmware update

Starting with XDS110 firmware version 3.0.0.0, the peak TCK
frequency became 14,000 kHz. So the delay count calculation
in the current driver has been updated to use the new
formula for setting the TCK speed depending on which version
of the firmware is detected. And because of the changes, the
default TCK settings for the XDS110 based Launchpads can be
adjusted to take advantage of the higher TCK performance.
Note that the values used have been determined through
testing in the automated test labs to be the highest TCK
frequency with the XDS110 that are still reliable.
Different boards have a different peak TCK setting that
should be safe.

Change-Id: I4d66e90d8fac8272641ba4db4a3a510e3b444d86
Signed-off-by: Edward Fewell <efewell@ti.com>
Reviewed-on: http://openocd.zylin.com/5493
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>

1 files changed, 112 insertions, 46 deletions

diff --git a/src/jtag/drivers/xds110.c b/src/jtag/drivers/xds110.c
index 69d9895..085d85f 100644
--- a/src/jtag/drivers/xds110.c
+++ b/src/jtag/drivers/xds110.c
@@ -41,6 +41,12 @@
 #define OCD_FIRMWARE_UPGRADE \
 	"XDS110: upgrade to version 2.3.0.11+ for improved support"
 
+/* Firmware version that introduced improved TCK performance */
+#define FAST_TCK_FIRMWARE_VERSION 0x03000000
+
+/* Firmware version that introduced 10 MHz and 12 MHz TCK support */
+#define FAST_TCK_PLUS_FIRMWARE_VERSION 0x03000003
+
 /***************************************************************************
  *   USB Connection Buffer Definitions                                     *
  ***************************************************************************/
@@ -91,8 +97,17 @@
 
 /* TCK frequency limits */
 #define XDS110_MIN_TCK_SPEED  100 /* kHz */
-#define XDS110_MAX_TCK_SPEED 2500 /* kHz */
-#define XDS110_TCK_PULSE_INCREMENT 66.0
+#define XDS110_MAX_SLOW_TCK_SPEED 2500 /* kHz */
+#define XDS110_MAX_FAST_TCK_SPEED 14000 /* kHz */
+#define XDS110_DEFAULT_TCK_SPEED 2500 /* kHz */
+
+/* Fixed TCK delay values for "Fast" TCK frequencies */
+#define FAST_TCK_DELAY_14000_KHZ 0
+#define FAST_TCK_DELAY_10000_KHZ 0xfffffffd
+#define FAST_TCK_DELAY_12000_KHZ 0xfffffffe
+#define FAST_TCK_DELAY_8500_KHZ 1
+#define FAST_TCK_DELAY_5500_KHZ 2
+/* For TCK frequencies below 5500 kHz, use calculated delay */
 
 /* Scan mode on connect */
 #define MODE_JTAG 1
@@ -249,7 +264,7 @@ static struct xds110_info xds110 = {
 	.is_cmapi_acquired = false,
 	.is_swd_mode = false,
 	.is_ap_dirty = false,
-	.speed = XDS110_MAX_TCK_SPEED,
+	.speed = XDS110_DEFAULT_TCK_SPEED,
 	.delay_count = 0,
 	.serial = {0},
 	.voltage = 0,
@@ -1846,6 +1861,8 @@ static int xds110_execute_queue(void)
 
 static int xds110_speed(int speed)
 {
+	double freq_to_use;
+	uint32_t delay_count;
 	bool success;
 
 	if (speed == 0) {
@@ -1853,61 +1870,110 @@ static int xds110_speed(int speed)
 		return ERROR_JTAG_NOT_IMPLEMENTED;
 	}
 
-	if (speed > XDS110_MAX_TCK_SPEED) {
-		LOG_INFO("XDS110: reduce speed request: %dkHz to %dkHz maximum",
-			speed, XDS110_MAX_TCK_SPEED);
-		speed = XDS110_MAX_TCK_SPEED;
-	}
-
 	if (speed < XDS110_MIN_TCK_SPEED) {
-		LOG_INFO("XDS110: increase speed request: %dkHz to %dkHz minimum",
+		LOG_INFO("XDS110: increase speed request: %d kHz to %d kHz minimum",
 			speed, XDS110_MIN_TCK_SPEED);
 		speed = XDS110_MIN_TCK_SPEED;
 	}
 
-	/* The default is the maximum frequency the XDS110 can support */
-	uint32_t freq_to_use = XDS110_MAX_TCK_SPEED * 1000; /* Hz */
-	uint32_t delay_count = 0;
+	/* Older XDS110 firmware had inefficient scan routines and could only */
+	/* achieve a peak TCK frequency of about 2500 kHz */
+	if (xds110.firmware < FAST_TCK_FIRMWARE_VERSION) {
 
-	if (XDS110_MAX_TCK_SPEED != speed) {
-		freq_to_use = speed * 1000; /* Hz */
+		/* Check for request for top speed or higher */
+		if (speed >= XDS110_MAX_SLOW_TCK_SPEED) {
 
-		/* Calculate the delay count value */
-		double one_giga = 1000000000;
-		/* Get the pulse duration for the maximum frequency supported in ns */
-		double max_freq_pulse_duration = one_giga /
-			(XDS110_MAX_TCK_SPEED * 1000);
+			/* Inform user that speed was adjusted down to max possible */
+			if (speed > XDS110_MAX_SLOW_TCK_SPEED) {
+				LOG_INFO(
+					"XDS110: reduce speed request: %d kHz to %d kHz maximum",
+					speed, XDS110_MAX_SLOW_TCK_SPEED);
+				speed = XDS110_MAX_SLOW_TCK_SPEED;
+			}
+			delay_count = 0;
 
-		/* Convert frequency to pulse duration */
-		double freq_to_pulse_width_in_ns = one_giga / freq_to_use;
+		} else {
 
-		/*
-		 * Start with the pulse duration for the maximum frequency. Keep
-		 * decrementing the time added by each count value till the requested
-		 * frequency pulse is less than the calculated value.
-		 */
-		double current_value = max_freq_pulse_duration;
+			const double XDS110_TCK_PULSE_INCREMENT = 66.0;
+			freq_to_use = speed * 1000; /* Hz */
+			delay_count = 0;
+
+			/* Calculate the delay count value */
+			double one_giga = 1000000000;
+			/* Get the pulse duration for the max frequency supported in ns */
+			double max_freq_pulse_duration = one_giga /
+				(XDS110_MAX_SLOW_TCK_SPEED * 1000);
+
+			/* Convert frequency to pulse duration */
+			double freq_to_pulse_width_in_ns = one_giga / freq_to_use;
 
-		while (current_value < freq_to_pulse_width_in_ns) {
-			current_value += XDS110_TCK_PULSE_INCREMENT;
-			++delay_count;
+			/*
+			* Start with the pulse duration for the maximum frequency. Keep
+			* decrementing time added by each count value till the requested
+			* frequency pulse is less than the calculated value.
+			*/
+			double current_value = max_freq_pulse_duration;
+
+			while (current_value < freq_to_pulse_width_in_ns) {
+				current_value += XDS110_TCK_PULSE_INCREMENT;
+				++delay_count;
+			}
+
+			/*
+			* Determine which delay count yields the best match.
+			* The one obtained above or one less.
+			*/
+			if (delay_count) {
+				double diff_freq_1 = freq_to_use -
+					(one_giga / (max_freq_pulse_duration +
+					(XDS110_TCK_PULSE_INCREMENT * delay_count)));
+				double diff_freq_2 = (one_giga / (max_freq_pulse_duration +
+					(XDS110_TCK_PULSE_INCREMENT * (delay_count - 1)))) -
+					freq_to_use;
+
+				/* One less count value yields a better match */
+				if (diff_freq_1 > diff_freq_2)
+					--delay_count;
+			}
 		}
 
-		/*
-		 * Determine which delay count yields the best match.
-		 * The one obtained above or one less.
-		 */
-		if (delay_count) {
-			double diff_freq_1 = freq_to_use -
-				(one_giga / (max_freq_pulse_duration +
-				(XDS110_TCK_PULSE_INCREMENT * delay_count)));
-			double diff_freq_2 = (one_giga / (max_freq_pulse_duration +
-				(XDS110_TCK_PULSE_INCREMENT * (delay_count - 1)))) -
-				freq_to_use;
-
-			/* One less count value yields a better match */
-			if (diff_freq_1 > diff_freq_2)
-				--delay_count;
+	/* Newer firmware has reworked TCK routines that are much more efficient */
+	/* and can now achieve a peak TCK frequency of 14000 kHz */
+	} else {
+
+		if (speed >= XDS110_MAX_FAST_TCK_SPEED) {
+			if (speed > XDS110_MAX_FAST_TCK_SPEED) {
+				LOG_INFO(
+					"XDS110: reduce speed request: %d kHz to %d kHz maximum",
+					speed, XDS110_MAX_FAST_TCK_SPEED);
+				speed = XDS110_MAX_FAST_TCK_SPEED;
+			}
+			delay_count = 0;
+		} else if (speed >= 12000 && xds110.firmware >=
+			FAST_TCK_PLUS_FIRMWARE_VERSION) {
+			delay_count = FAST_TCK_DELAY_12000_KHZ;
+		} else if (speed >= 10000 && xds110.firmware >=
+			FAST_TCK_PLUS_FIRMWARE_VERSION) {
+			delay_count = FAST_TCK_DELAY_10000_KHZ;
+		} else if (speed >= 8500) {
+			delay_count = FAST_TCK_DELAY_8500_KHZ;
+		} else if (speed >= 5500) {
+			delay_count = FAST_TCK_DELAY_5500_KHZ;
+		} else {
+			/* Calculate the delay count to set the frequency */
+			/* Formula determined by measuring the waveform on Saeleae logic */
+			/* analyzer using known values for delay count */
+			const double m = 17100000.0; /* slope */
+			const double b = -1.02;      /* y-intercept */
+
+			freq_to_use = speed * 1000; /* Hz */
+			double period = 1.0/freq_to_use;
+			double delay = m * period + b;
+
+			if (delay < 1.0)
+				delay_count = 1;
+			else
+				delay_count = (uint32_t)delay;
 		}
 	}