S5P: Serial: Add fdt support to driver

This patch adds FDT support to the serial s5p driver.
At present disabling the serial console (from the device tree) crashes
U-Boot. Add checks for this case, so that execution can continue without
a serial console.
It also enables the serial_s5p driver recognize the silent_console option.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Gabe Black <gabeblack@google.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

drivers/serial/serial_s5p.c

@@ -22,6 +22,7 @@
  */
 
 #include <common.h>
+#include <fdtdec.h>
 #include <linux/compiler.h>
 #include <asm/io.h>
 #include <asm/arch/uart.h>
@@ -34,10 +35,21 @@ DECLARE_GLOBAL_DATA_PTR;
 #define RX_FIFO_FULL_MASK	(1 << 8)
 #define TX_FIFO_FULL_MASK	(1 << 24)
 
+/* Information about a serial port */
+struct fdt_serial {
+	u32 base_addr;  /* address of registers in physical memory */
+	u8 port_id;     /* uart port number */
+	u8 enabled;     /* 1 if enabled, 0 if disabled */
+} config __attribute__ ((section(".data")));
+
 static inline struct s5p_uart *s5p_get_base_uart(int dev_index)
 {
+#ifdef CONFIG_OF_CONTROL
+	return (struct s5p_uart *)(config.base_addr);
+#else
 	u32 offset = dev_index * sizeof(struct s5p_uart);
 	return (struct s5p_uart *)(samsung_get_base_uart() + offset);
+#endif
 }
 
 /*
@@ -73,6 +85,16 @@ void serial_setbrg_dev(const int dev_index)
 	u32 baudrate = gd->baudrate;
 	u32 val;
 
+#if defined(CONFIG_SILENT_CONSOLE) && \
+		defined(CONFIG_OF_CONTROL) && \
+		!defined(CONFIG_SPL_BUILD)
+	if (fdtdec_get_config_int(gd->fdt_blob, "silent_console", 0))
+		gd->flags |= GD_FLG_SILENT;
+#endif
+
+	if (!config.enabled)
+		return;
+
 	val = uclk / baudrate;
 
 	writel(val / 16 - 1, &uart->ubrdiv);
@@ -133,6 +155,9 @@ int serial_getc_dev(const int dev_index)
 {
 	struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 
+	if (!config.enabled)
+		return 0;
+
 	/* wait for character to arrive */
 	while (!(readl(&uart->ufstat) & (RX_FIFO_COUNT_MASK |
 					 RX_FIFO_FULL_MASK))) {
@@ -150,6 +175,9 @@ void serial_putc_dev(const char c, const int dev_index)
 {
 	struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 
+	if (!config.enabled)
+		return;
+
 	/* wait for room in the tx FIFO */
 	while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) {
 		if (serial_err_check(dev_index, 1))
@@ -170,6 +198,9 @@ int serial_tstc_dev(const int dev_index)
 {
 	struct s5p_uart *const uart = s5p_get_base_uart(dev_index);
 
+	if (!config.enabled)
+		return 0;
+
 	return (int)(readl(&uart->utrstat) & 0x1);
 }
 
@@ -212,8 +243,54 @@ DECLARE_S5P_SERIAL_FUNCTIONS(3);
 struct serial_device s5p_serial3_device =
 	INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3");
 
+#ifdef CONFIG_OF_CONTROL
+int fdtdec_decode_console(int *index, struct fdt_serial *uart)
+{
+	const void *blob = gd->fdt_blob;
+	int node;
+
+	node = fdt_path_offset(blob, "console");
+	if (node < 0)
+		return node;
+
+	uart->base_addr = fdtdec_get_addr(blob, node, "reg");
+	if (uart->base_addr == FDT_ADDR_T_NONE)
+		return -FDT_ERR_NOTFOUND;
+
+	uart->port_id = fdtdec_get_int(blob, node, "id", -1);
+	uart->enabled = fdtdec_get_is_enabled(blob, node);
+
+	return 0;
+}
+#endif
+
 __weak struct serial_device *default_serial_console(void)
 {
+#ifdef CONFIG_OF_CONTROL
+	int index = 0;
+
+	if ((!config.base_addr) && (fdtdec_decode_console(&index, &config))) {
+		debug("Cannot decode default console node\n");
+		return NULL;
+	}
+
+	switch (config.port_id) {
+	case 0:
+		return &s5p_serial0_device;
+	case 1:
+		return &s5p_serial1_device;
+	case 2:
+		return &s5p_serial2_device;
+	case 3:
+		return &s5p_serial3_device;
+	default:
+		debug("Unknown config.port_id: %d", config.port_id);
+		break;
+	}
+
+	return NULL;
+#else
+	config.enabled = 1;
 #if defined(CONFIG_SERIAL0)
 	return &s5p_serial0_device;
 #elif defined(CONFIG_SERIAL1)
@@ -225,6 +302,7 @@ __weak struct serial_device *default_serial_console(void)
 #else
 #error "CONFIG_SERIAL? missing."
 #endif
+#endif
 }
 
 void s5p_serial_initialize(void)