ft2232 init mess cleanup

In the ft2232 driver, initialization for many layouts punts to a routine
called usbjtag_init(), instead of a routine specific to each layout.

That routine is  a mess  built around a "what type layout am I" core.
That's a bad design ... in this case, especially so, since it bypasses
the layout-specific dispatch which was just done, and obfuscates the
initialization which is at least somewhat generic, instead of being
specific to the "usbjtag" layout.

Split and document out the generic parts of usbjtag_init(), and make
the rest of those layouts have layout-specific init methods.  Also,
rename usbjtag_reset() ... that also was not specific to the "usbjtag"
layout, and thus contributed to the previous code structure confusion.

(Eventually, all layout-specific code (and method tables) should probably
live in files specific to each layout.  These changes will facilitate
those and other cleanups to this driver.)

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

1 files changed, 99 insertions, 60 deletions

diff --git a/src/jtag/drivers/ft2232.c b/src/jtag/drivers/ft2232.c
index 8e835c59..dd11aec6 100644
--- a/src/jtag/drivers/ft2232.c
+++ b/src/jtag/drivers/ft2232.c
@@ -172,6 +172,8 @@ struct ft2232_layout {
 /* init procedures for supported layouts */
 static int usbjtag_init(void);
 static int jtagkey_init(void);
+static int lm3s811_jtag_init(void);
+static int icdi_jtag_init(void);
 static int olimex_jtag_init(void);
 static int flyswatter_init(void);
 static int turtle_init(void);
@@ -181,12 +183,13 @@ static int axm0432_jtag_init(void);
 static int sheevaplug_init(void);
 static int icebear_jtag_init(void);
 static int cortino_jtag_init(void);
+static int signalyzer_init(void);
 static int signalyzer_h_init(void);
 static int ktlink_init(void);
 static int redbee_init(void);
 
 /* reset procedures for supported layouts */
-static void usbjtag_reset(int trst, int srst);
+static void ftx23_reset(int trst, int srst);
 static void jtagkey_reset(int trst, int srst);
 static void olimex_jtag_reset(int trst, int srst);
 static void flyswatter_reset(int trst, int srst);
@@ -211,7 +214,7 @@ static const struct ft2232_layout  ft2232_layouts[] =
 {
 	{ .name = "usbjtag",
 		.init = usbjtag_init,
-		.reset = usbjtag_reset,
+		.reset = ftx23_reset,
 	},
 	{ .name = "jtagkey",
 		.init = jtagkey_init,
@@ -226,16 +229,16 @@ static const struct ft2232_layout  ft2232_layouts[] =
 		.reset = jtagkey_reset,
 	},
 	{ .name = "signalyzer",
-		.init = usbjtag_init,
-		.reset = usbjtag_reset,
+		.init = signalyzer_init,
+		.reset = ftx23_reset,
 	},
 	{ .name = "evb_lm3s811",
-		.init = usbjtag_init,
-		.reset = usbjtag_reset,
+		.init = lm3s811_jtag_init,
+		.reset = ftx23_reset,
 	},
 	{ .name = "luminary_icdi",
-		.init = usbjtag_init,
-		.reset = usbjtag_reset,
+		.init = icdi_jtag_init,
+		.reset = ftx23_reset,
 	},
 	{ .name = "olimex-jtag",
 		.init = olimex_jtag_init,
@@ -298,14 +301,23 @@ static const struct ft2232_layout  ft2232_layouts[] =
 	{ .name = NULL, /* END OF TABLE */ },
 };
 
-static uint8_t                  nTRST, nTRSTnOE, nSRST, nSRSTnOE;
+/* bitmask used to drive nTRST; usually a GPIOLx signal */
+static uint8_t                  nTRST;
+static uint8_t                  nTRSTnOE;
+/* bitmask used to drive nSRST; usually a GPIOLx signal */
+static uint8_t                  nSRST;
+static uint8_t                  nSRSTnOE;
 
 /** the layout being used with this debug session */
 static const struct ft2232_layout *layout;
 
+/** default bitmask values ddriven on DBUS: TCK/TDI/TDO/TMS and GPIOL(0..4) */
 static uint8_t                  low_output     = 0x0;
+/** default direction bitmask for DBUS: TCK/TDI/TDO/TMS and GPIOL(0..4) */
 static uint8_t                  low_direction  = 0x0;
+/** default value bitmask for CBUS GPIOH(0..4) */
 static uint8_t                  high_output    = 0x0;
+/** default direction bitmask for CBUS GPIOH(0..4) */
 static uint8_t                  high_direction = 0x0;
 
 #if BUILD_FT2232_FTD2XX == 1
@@ -1340,7 +1352,8 @@ static int ft2232_predict_scan_in(int scan_size, enum scan_type type)
 	return predicted_size;
 }
 
-static void usbjtag_reset(int trst, int srst)
+/* semi-generic FT2232/FT4232 reset code */
+static void ftx23_reset(int trst, int srst)
 {
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
 	if (trst == 1)
@@ -2371,60 +2384,23 @@ static int ft2232_init(void)
 	return ERROR_OK;
 }
 
-static int usbjtag_init(void)
+/** Updates defaults for DBUS signals:  the four JTAG signals
+ * (TCK, TDI, TDO, TMS) and * the four GPIOL signals.
+ */
+static inline void ftx232_init_head(void)
 {
-	uint8_t  buf[3];
-	uint32_t bytes_written;
-	char *ft2232_layout = layout->name;
-
 	low_output    = 0x08;
 	low_direction = 0x0b;
+}
 
-	if (strcmp(ft2232_layout, "usbjtag") == 0)
-	{
-		nTRST    = 0x10;
-		nTRSTnOE = 0x10;
-		nSRST    = 0x40;
-		nSRSTnOE = 0x40;
-	}
-	else if (strcmp(ft2232_layout, "signalyzer") == 0)
-	{
-		nTRST    = 0x10;
-		nTRSTnOE = 0x10;
-		nSRST    = 0x20;
-		nSRSTnOE = 0x20;
-	}
-	else if (strcmp(ft2232_layout, "evb_lm3s811") == 0)
-	{
-		/* There are multiple revisions of LM3S811 eval boards:
-		 * - Rev B (and older?) boards have no SWO trace support.
-		 * - Rev C boards add ADBUS_6 DBG_ENn and BDBUS_4 SWO_EN;
-		 *   they should use the "luminary_icdi" layout instead.
-		 */
-		nTRST = 0x0;
-		nTRSTnOE = 0x00;
-		nSRST = 0x20;
-		nSRSTnOE = 0x20;
-		low_output    = 0x88;
-		low_direction = 0x8b;
-	}
-	else if (strcmp(ft2232_layout, "luminary_icdi") == 0)
-	{
-		/* Most Luminary eval boards support SWO trace output,
-		 * and should use this "luminary_icdi" layout.
-		 */
-		nTRST = 0x0;
-		nTRSTnOE = 0x00;
-		nSRST = 0x20;
-		nSRSTnOE = 0x20;
-		low_output    = 0x88;
-		low_direction = 0xcb;
-	}
-	else
-	{
-		LOG_ERROR("BUG: usbjtag_init called for unknown layout '%s'", ft2232_layout);
-		return ERROR_JTAG_INIT_FAILED;
-	}
+/** Initializes DBUS signals:  the four JTAG signals (TCK, TDI, TDO, TMS),
+ * the four GPIOL signals.  Initialization covers value and direction,
+ * as customized for each layout.
+ */
+static int ftx232_init_tail(void)
+{
+	uint8_t  buf[3];
+	uint32_t bytes_written;
 
 	enum reset_types jtag_reset_config = jtag_get_reset_config();
 	if (jtag_reset_config & RESET_TRST_OPEN_DRAIN)
@@ -2464,6 +2440,69 @@ static int usbjtag_init(void)
 	return ERROR_OK;
 }
 
+static int usbjtag_init(void)
+{
+	/*
+	 * NOTE:  This is now _specific_ to the "usbjtag" layout.
+	 * Don't try cram any more layouts into this.
+	 */
+	ftx232_init_head();
+
+	nTRST    = 0x10;
+	nTRSTnOE = 0x10;
+	nSRST    = 0x40;
+	nSRSTnOE = 0x40;
+
+	return ftx232_init_tail();
+}
+
+static int lm3s811_jtag_init(void)
+{
+	ftx232_init_head();
+
+	/* There are multiple revisions of LM3S811 eval boards:
+	 * - Rev B (and older?) boards have no SWO trace support.
+	 * - Rev C boards add ADBUS_6 DBG_ENn and BDBUS_4 SWO_EN;
+	 *   they should use the "luminary_icdi" layout instead.
+	 */
+	nTRST = 0x0;
+	nTRSTnOE = 0x00;
+	nSRST = 0x20;
+	nSRSTnOE = 0x20;
+	low_output    = 0x88;
+	low_direction = 0x8b;
+
+	return ftx232_init_tail();
+}
+
+static int icdi_jtag_init(void)
+{
+	ftx232_init_head();
+
+	/* Most Luminary eval boards support SWO trace output,
+	 * and should use this "luminary_icdi" layout.
+	 */
+	nTRST = 0x0;
+	nTRSTnOE = 0x00;
+	nSRST = 0x20;
+	nSRSTnOE = 0x20;
+	low_output    = 0x88;
+	low_direction = 0xcb;
+
+	return ftx232_init_tail();
+}
+
+static int signalyzer_init(void)
+{
+	ftx232_init_head();
+
+	nTRST    = 0x10;
+	nTRSTnOE = 0x10;
+	nSRST    = 0x20;
+	nSRSTnOE = 0x20;
+	return ftx232_init_tail();
+}
+
 static int axm0432_jtag_init(void)
 {
 	uint8_t  buf[3];