serial: bfin: Flip the jtag serial console to CONFIG_SERIAL_MULTI

Rework the emulation of serial console via JTAG from simple ad-hoc
implementation of serial port routines to CONFIG_SERIAL_MULTI and
enable CONFIG_SERIAL_MULTI unconditionally for blackfin.

In order for the JTAG serial console to take precedence over all
other serial ports available in system, implement override for
default_serial_console call returning this JTAG serial console.

This brings in a bit of a growth of size, but eventually will allow
us to unconditionally enable CONFIG_SERIAL_MULTI throughout the whole
U-Boot and maintain only one serial subsystem.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Tom Rini <trini@ti.com>
Cc: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/cpu/jtag-console.c

@@ -194,12 +194,35 @@ int drv_jtag_console_init(void)
 }
 
 #ifdef CONFIG_UART_CONSOLE_IS_JTAG
+#include <serial.h>
 /* Since the JTAG is always available (at power on), allow it to fake a UART */
-void serial_set_baud(uint32_t baud) {}
-void serial_setbrg(void)            {}
-int serial_init(void)               { return 0; }
-void serial_putc(const char c)      __attribute__((alias("jtag_putc")));
-void serial_puts(const char *s)     __attribute__((alias("jtag_puts")));
-int serial_tstc(void)               __attribute__((alias("jtag_tstc")));
-int serial_getc(void)               __attribute__((alias("jtag_getc")));
+void jtag_serial_setbrg(void)
+{
+}
+
+int jtag_serial_init(void)
+{
+	return 0;
+}
+
+static struct serial_device serial_jtag_drv = {
+	.name	= "jtag",
+	.start	= jtag_serial_init,
+	.stop	= NULL,
+	.setbrg	= jtag_serial_setbrg,
+	.putc	= jtag_putc,
+	.puts	= jtag_puts,
+	.tstc	= jtag_tstc,
+	.getc	= jtag_getc,
+};
+
+void bfin_jtag_initialize(void)
+{
+	serial_register(&serial_jtag_drv);
+}
+
+struct serial_device *default_serial_console(void)
+{
+	return &serial_jtag_drv;
+}
 #endif

common/serial.c

@@ -47,6 +47,7 @@ serial_initfunc(s3c24xx_serial_initialize);
 serial_initfunc(s5p_serial_initialize);
 serial_initfunc(zynq_serial_initalize);
 serial_initfunc(bfin_serial_initialize);
+serial_initfunc(bfin_jtag_initialize);
 serial_initfunc(mpc512x_serial_initialize);
 serial_initfunc(uartlite_serial_initialize);
 
@@ -74,6 +75,7 @@ void serial_initialize(void)
 	s5p_serial_initialize();
 	mpc512x_serial_initialize();
 	bfin_serial_initialize();
+	bfin_jtag_initialize();
 	uartlite_serial_initialize();
 	zynq_serial_initalize();
 	serial_assign(default_serial_console()->name);

include/configs/bfin_adi_common.h

@@ -108,11 +108,11 @@
 #define CONFIG_LOADS_ECHO	1
 #define CONFIG_JTAG_CONSOLE
 #define CONFIG_SILENT_CONSOLE
+#define CONFIG_SERIAL_MULTI
 #ifndef CONFIG_BAUDRATE
 # define CONFIG_BAUDRATE	57600
 #endif
 #ifndef CONFIG_DEBUG_EARLY_SERIAL
-# define CONFIG_SERIAL_MULTI
 # define CONFIG_SYS_BFIN_UART
 #endif