Blackfin arch: Initial patch to add earlyprintk support

This allows debugging of problems which happen eary in the kernel
boot process (after bootargs are parsed, but before serial subsystem
is fully initialized)

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

1 files changed, 101 insertions, 28 deletions

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 1e79ee605d93..5039e2675abc 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -962,30 +962,6 @@ static void __init bfin_serial_init_ports(void)
 }
 
 #ifdef CONFIG_SERIAL_BFIN_CONSOLE
-static void bfin_serial_console_putchar(struct uart_port *port, int ch)
-{
-	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
-	while (!(UART_GET_LSR(uart) & THRE))
-		barrier();
-	UART_PUT_CHAR(uart, ch);
-	SSYNC();
-}
-
-/*
- * Interrupts are disabled on entering
- */
-static void
-bfin_serial_console_write(struct console *co, const char *s, unsigned int count)
-{
-	struct bfin_serial_port *uart = &bfin_serial_ports[co->index];
-	int flags = 0;
-
-	spin_lock_irqsave(&uart->port.lock, flags);
-	uart_console_write(&uart->port, s, count, bfin_serial_console_putchar);
-	spin_unlock_irqrestore(&uart->port.lock, flags);
-
-}
-
 /*
  * If the port was already initialised (eg, by a boot loader),
  * try to determine the current setup.
@@ -1038,19 +1014,25 @@ bfin_serial_console_get_options(struct bfin_serial_port *uart, int *baud,
 	}
 	pr_debug("%s:baud = %d, parity = %c, bits= %d\n", __FUNCTION__, *baud, *parity, *bits);
 }
+#endif
+
+#if defined(CONFIG_SERIAL_BFIN_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
+static struct uart_driver bfin_serial_reg;
 
 static int __init
 bfin_serial_console_setup(struct console *co, char *options)
 {
 	struct bfin_serial_port *uart;
+# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	int baud = 57600;
 	int bits = 8;
 	int parity = 'n';
-#ifdef CONFIG_SERIAL_BFIN_CTSRTS
+#  ifdef CONFIG_SERIAL_BFIN_CTSRTS
 	int flow = 'r';
-#else
+#  else
 	int flow = 'n';
-#endif
+#  endif
+# endif
 
 	/*
 	 * Check whether an invalid uart number has been specified, and
@@ -1061,15 +1043,45 @@ bfin_serial_console_setup(struct console *co, char *options)
 		co->index = 0;
 	uart = &bfin_serial_ports[co->index];
 
+# ifdef CONFIG_SERIAL_BFIN_CONSOLE
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else
 		bfin_serial_console_get_options(uart, &baud, &parity, &bits);
 
 	return uart_set_options(&uart->port, co, baud, parity, bits, flow);
+# else
+	return 0;
+# endif
+}
+#endif /* defined (CONFIG_SERIAL_BFIN_CONSOLE) ||
+				 defined (CONFIG_EARLY_PRINTK) */
+
+#ifdef CONFIG_SERIAL_BFIN_CONSOLE
+static void bfin_serial_console_putchar(struct uart_port *port, int ch)
+{
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+	while (!(UART_GET_LSR(uart) & THRE))
+		barrier();
+	UART_PUT_CHAR(uart, ch);
+	SSYNC();
+}
+
+/*
+ * Interrupts are disabled on entering
+ */
+static void
+bfin_serial_console_write(struct console *co, const char *s, unsigned int count)
+{
+	struct bfin_serial_port *uart = &bfin_serial_ports[co->index];
+	int flags = 0;
+
+	spin_lock_irqsave(&uart->port.lock, flags);
+	uart_console_write(&uart->port, s, count, bfin_serial_console_putchar);
+	spin_unlock_irqrestore(&uart->port.lock, flags);
+
 }
 
-static struct uart_driver bfin_serial_reg;
 static struct console bfin_serial_console = {
 	.name		= BFIN_SERIAL_NAME,
 	.write		= bfin_serial_console_write,
@@ -1095,7 +1107,68 @@ console_initcall(bfin_serial_rs_console_init);
 #define BFIN_SERIAL_CONSOLE	&bfin_serial_console
 #else
 #define BFIN_SERIAL_CONSOLE	NULL
+#endif /* CONFIG_SERIAL_BFIN_CONSOLE */
+
+
+#ifdef CONFIG_EARLY_PRINTK
+static __init void early_serial_putc(struct uart_port *port, int ch)
+{
+	unsigned timeout = 0xffff;
+	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
+
+	while ((!(UART_GET_LSR(uart) & THRE)) && --timeout)
+		cpu_relax();
+	UART_PUT_CHAR(uart, ch);
+}
+
+static __init void early_serial_write(struct console *con, const char *s,
+					unsigned int n)
+{
+	struct bfin_serial_port *uart = &bfin_serial_ports[con->index];
+	unsigned int i;
+
+	for (i = 0; i < n; i++, s++) {
+		if (*s == '\n')
+			early_serial_putc(&uart->port, '\r');
+		early_serial_putc(&uart->port, *s);
+	}
+}
+
+static struct __init console bfin_early_serial_console = {
+	.name = "early_BFuart",
+	.write = early_serial_write,
+	.device = uart_console_device,
+	.flags = CON_PRINTBUFFER,
+	.setup = bfin_serial_console_setup,
+	.index = -1,
+	.data  = &bfin_serial_reg,
+};
+
+struct console __init *bfin_earlyserial_init(unsigned int port,
+						unsigned int cflag)
+{
+	struct bfin_serial_port *uart;
+	struct ktermios t;
+
+	if (port == -1 || port >= nr_ports)
+		port = 0;
+	bfin_serial_init_ports();
+	bfin_early_serial_console.index = port;
+#ifdef CONFIG_KGDB_UART
+	kgdb_entry_state = 0;
+	init_kgdb_uart();
 #endif
+	uart = &bfin_serial_ports[port];
+	t.c_cflag = cflag;
+	t.c_iflag = 0;
+	t.c_oflag = 0;
+	t.c_lflag = ICANON;
+	t.c_line = port;
+	bfin_serial_set_termios(&uart->port, &t, &t);
+	return &bfin_early_serial_console;
+}
+
+#endif /* CONFIG_SERIAL_BFIN_CONSOLE */
 
 static struct uart_driver bfin_serial_reg = {
 	.owner			= THIS_MODULE,