[U-Boot] WIP: fdt: Add serial port controlled by device tree

diff --git a/common/fdt_decode.c b/common/fdt_decode.c
new file mode 100644
index 0000000..2541147
--- /dev/null
+++ b/common/fdt_decode.c
@@ -0,0 +1,214 @@ 
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <serial.h>
+#include <libfdt.h>
+#include <fdt_support.h>
+#include <fdt_decode.h>
+
+/*
+ * Here are the type we know about. One day we might allow drivers to
+ * register. For now we just put them here.
+ */
+static struct fdt_compat compat_types[] = {
+	{ COMPAT_UNKNOWN, "<none>" },
+	{ COMPAT_SPI_UART_SWITCH, "spi-uart-select" },
+	{ COMPAT_SERIAL_NS16550, "ns16550" },
+};
+
+/**
+ * Look in the FDT for an alias with the given name and return its node.
+ *
+ * @param blob	FDT blob
+ * @param name	alias name to look up
+ * @return node offset if found, or an error code < 0 otherwise
+ */
+static int find_alias_node(const void *blob, const char *name)
+{
+	const char *path;
+	int alias_node;
+
+	alias_node = fdt_path_offset(blob, "/aliases");
+	if (alias_node < 0)
+		return alias_node;
+	path = fdt_getprop(blob, alias_node, name, NULL);
+	if (!path)
+		return -FDT_ERR_NOTFOUND;
+	return fdt_path_offset(blob, path);
+}
+
+/**
+ * Look up an address property in a node and return it as an address.
+ * The property must hold exactly one address with no trailing data.
+ * This is only tested on 32-bit machines.
+ *
+ * @param blob	FDT blob
+ * @param node	node to examine
+ * @param prop_name	name of property to find
+ * @return address, if found, or ADDR_T_NONE if not
+ */
+static addr_t get_addr(const void *blob, int node, const char *prop_name)
+{
+	const addr_t *cell;
+	int len;
+
+	cell = fdt_getprop(blob, node, prop_name, &len);
+	if (cell && len != sizeof(addr_t))
+		return addr_to_cpu(*cell);
+	return ADDR_T_NONE;
+}
+
+/**
+ * Look up a 32-bit integer property in a node and return it. The property
+ * must have at least 4 bytes of data. The value of the first cell is
+ * returned.
+ *
+ * @param blob	FDT blob
+ * @param node	node to examine
+ * @param prop_name	name of property to find
+ * @param default_val	default value to return if the property is not found
+ * @return integer value, if found, or default_val if not
+ */
+static s32 get_int(const void *blob, int node, const char *prop_name,
+		s32 default_val)
+{
+	const s32 *cell;
+	int len;
+
+	cell = fdt_getprop(blob, node, prop_name, &len);
+	if (cell && len >= sizeof(s32))
+		return fdt32_to_cpu(cell[0]);
+	return default_val;
+}
+
+/**
+ * Look up a phandle and follow it to its node. Then return the offset
+ * of that node.
+ *
+ * @param blob		FDT blob
+ * @param node		node to examine
+ * @param prop_name	name of property to find
+ * @return node offset if found, -ve error code on error
+ */
+static int lookup_phandle(const void *blob, int node, const char *prop_name)
+{
+	const u32 *phandle;
+	int lookup;
+
+	phandle = fdt_getprop(blob, node, prop_name, NULL);
+	if (!phandle)
+		return -FDT_ERR_NOTFOUND;
+
+	lookup = fdt_node_offset_by_phandle(blob, fdt32_to_cpu(*phandle));
+	return lookup;
+}
+
+/**
+ * Checks whether a node is enabled.
+ * This looks for a 'status' property. If this exists, then returns 1 if
+ * the status is 'ok' and 0 otherwise. If there is no status property,
+ * it returns the default value.
+ *
+ * @param blob	FDT blob
+ * @param node	node to examine
+ * @param default_val	default value to return if no 'status' property exists
+ * @return integer value 0/1, if found, or default_val if not
+ */
+static int get_is_enabled(const void *blob, int node, int default_val)
+{
+	const char *cell;
+
+	cell = fdt_getprop(blob, node, "status", NULL);
+	if (cell)
+		return 0 == strcmp(cell, "ok");
+	return default_val;
+}
+
+void fdt_decode_uart_calc_divisor(struct fdt_uart *uart)
+{
+	if (uart->multiplier && uart->baudrate)
+		uart->divisor = (uart->clock_freq +
+				(uart->baudrate * (uart->multiplier / 2))) /
+			(uart->multiplier * uart->baudrate);
+}
+
+int fdt_decode_uart_console(const void *blob, struct fdt_uart *uart,
+		int default_baudrate)
+{
+	int node;
+
+	node = find_alias_node(blob, "console");
+	if (node < 0)
+		return node;
+	uart->reg = get_addr(blob, node, "reg");
+	uart->id = get_int(blob, node, "id", 0);
+	uart->reg_shift = get_int(blob, node, "reg_shift", 2);
+	uart->baudrate = get_int(blob, node, "baudrate", default_baudrate);
+	uart->clock_freq = get_int(blob, node, "clock-frequency", -1);
+	uart->multiplier = get_int(blob, node, "multiplier", 16);
+	uart->divisor = get_int(blob, node, "divisor", -1);
+	uart->enabled = get_is_enabled(blob, node, 1);
+	uart->interrupt = get_int(blob, node, "interrupts", -1);
+	uart->silent = get_int(blob, node, "silent", 0);
+	uart->compat = fdt_decode_lookup(blob, node);
+
+	/* Calculate divisor if required */
+	if (uart->divisor == -1)
+		fdt_decode_uart_calc_divisor(uart);
+	return 0;
+}
+
+enum fdt_compat_id fdt_decode_lookup(const void *blob, int node)
+{
+	enum fdt_compat_id id;
+
+	/* Search our drivers */
+	for (id = COMPAT_UNKNOWN; id < COMPAT_COUNT; id++)
+		if (0 == fdt_node_check_compatible(blob, node,
+				compat_types[id].name))
+			return id;
+	return COMPAT_UNKNOWN;
+}
+
+int fdt_decode_get_spi_switch(const void *blob, struct fdt_spi_uart *config)
+{
+	int node, uart_node;
+	const u32 *gpio;
+
+	node = fdt_node_offset_by_compatible(blob, 0,
+					     "nvidia,spi-uart-switch");
+	if (node < 0)
+		return node;
+
+	uart_node = lookup_phandle(blob, node, "uart");
+	if (uart_node < 0)
+		return uart_node;
+	config->port = get_int(blob, uart_node, "id", -1);
+	if (config->port == -1)
+		return -FDT_ERR_NOTFOUND;
+	config->gpio = -1;
+	config->regs = (NS16550_t)get_addr(blob, uart_node, "reg");
+	gpio = fdt_getprop(blob, node, "gpios", NULL);
+	if (gpio)
+		config->gpio = fdt32_to_cpu(gpio[1]);
+	return 0;
+}
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 616b857..9135b91 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -55,6 +55,7 @@  COBJS-$(CONFIG_S3C44B0_SERIAL) += serial_s3c44b0.o
 COBJS-$(CONFIG_XILINX_UARTLITE) += serial_xuartlite.o
 COBJS-$(CONFIG_SANDBOX_SERIAL) += sandbox.o
 COBJS-$(CONFIG_SCIF_CONSOLE) += serial_sh.o
+COBJS-$(CONFIG_OF_SERIAL) += serial_fdt.o
 
 ifndef CONFIG_SPL_BUILD
 COBJS-$(CONFIG_USB_TTY) += usbtty.o
diff --git a/drivers/serial/serial_fdt.c b/drivers/serial/serial_fdt.c
new file mode 100644
index 0000000..1ba5bb3
--- /dev/null
+++ b/drivers/serial/serial_fdt.c
@@ -0,0 +1,228 @@ 
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * This is a serial port provided by the flattened device tree. It works
+ * by selecting a compiled in driver according to the setting in the FDT.
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <ns16550.h>
+#include <serial.h>
+#include <serial_fdt.h>
+
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/* Information obtained about a UART from the FDT */
+struct fdt_uart {
+	fdt_addr_t reg;	/* address of registers in physical memory */
+	int id;		/* id or port number (numbered from 0, default -1) */
+	int reg_shift;	/* each register is (1 << reg_shift) apart */
+	int baudrate;	/* baud rate, will be gd->baudrate if not defined */
+	int clock_freq;	/* clock frequency, -1 if not provided */
+	int multiplier;	/* divisor multiplier, default 16 */
+	int divisor;	/* baud rate divisor, default calculated */
+	int enabled;	/* 1 to enable, 0 to disable */
+	int interrupt;	/* interrupt line */
+	int silent;	/* 1 for silent UART (supresses output by default) */
+	enum fdt_compat_id compat; /* our selected driver */
+};
+
+/*
+ * We need these structures to be outside BSS since they are accessed before
+ * relocation.
+ */
+static struct serial_device console = {
+	"not_in_bss"
+};
+
+struct fdt_uart console_uart = {
+	-1U
+};
+
+void uart_calc_divisor(struct fdt_uart *uart)
+{
+	if (uart->multiplier && uart->baudrate)
+		uart->divisor = (uart->clock_freq +
+				(uart->baudrate * (uart->multiplier / 2))) /
+			(uart->multiplier * uart->baudrate);
+}
+
+static int decode_uart_console(const void *blob, struct fdt_uart *uart,
+		int default_baudrate)
+{
+	int node;
+
+	node = fdtdec_find_alias_node(blob, "console");
+	if (node < 0)
+		return node;
+	uart->reg = fdtdec_get_addr(blob, node, "reg");
+	uart->id = fdtdec_get_int(blob, node, "id", 0);
+	uart->reg_shift = fdtdec_get_int(blob, node, "reg_shift", 2);
+	uart->baudrate = fdtdec_get_int(blob, node, "baudrate",
+					default_baudrate);
+	uart->clock_freq = fdtdec_get_int(blob, node, "clock-frequency", -1);
+	uart->multiplier = fdtdec_get_int(blob, node, "multiplier", 16);
+	uart->divisor = fdtdec_get_int(blob, node, "divisor", -1);
+	uart->enabled = fdtdec_get_is_enabled(blob, node, 1);
+	uart->interrupt = fdtdec_get_int(blob, node, "interrupts", -1);
+	uart->compat = fdtdec_lookup(blob, node);
+
+	/* Calculate divisor if required */
+	if ((uart->divisor == -1) && (uart->clock_freq != -1))
+		uart_calc_divisor(uart);
+	return 0;
+}
+
+/* Access the console - this may need to be a function */
+#define DECLARE_CONSOLE	struct fdt_uart *uart = &console_uart
+
+/* Initialize the serial port */
+static int fserial_init(void)
+{
+	DECLARE_CONSOLE;
+
+	switch (uart->compat) {
+#ifdef CONFIG_SYS_NS16550
+	case COMPAT_SERIAL_NS16550:
+		NS16550_init((NS16550_t)uart->reg, uart->divisor);
+		break;
+#endif
+	default:
+		break;
+	}
+	return 0;
+}
+
+static void fserial_putc(const char c)
+{
+	DECLARE_CONSOLE;
+
+	if (c == '\n')
+		fserial_putc('\r');
+	switch (uart->compat) {
+#ifdef CONFIG_SYS_NS16550
+	case COMPAT_SERIAL_NS16550:
+		NS16550_putc((NS16550_t)uart->reg, c);
+		break;
+#endif
+	default:
+		break;
+	}
+}
+
+static void fserial_puts(const char *s)
+{
+	while (*s)
+		fserial_putc(*s++);
+}
+
+static int fserial_getc(void)
+{
+	DECLARE_CONSOLE;
+
+	switch (uart->compat) {
+#ifdef CONFIG_SYS_NS16550
+	case COMPAT_SERIAL_NS16550:
+		return NS16550_getc((NS16550_t)uart->reg);
+#endif
+	default:
+		break;
+	}
+	hang();
+
+	return 0;
+}
+
+static int fserial_tstc(void)
+{
+	DECLARE_CONSOLE;
+
+	switch (uart->compat) {
+#ifdef CONFIG_SYS_NS16550
+	case COMPAT_SERIAL_NS16550:
+		return NS16550_tstc((NS16550_t)uart->reg);
+#endif
+	default:
+		break;
+	}
+	return 0;
+}
+
+static void fserial_setbrg(void)
+{
+	DECLARE_CONSOLE;
+
+	uart->baudrate = gd->baudrate;
+	uart_calc_divisor(uart);
+	switch (uart->compat) {
+#ifdef CONFIG_SYS_NS16550
+	case COMPAT_SERIAL_NS16550:
+		NS16550_reinit((NS16550_t)uart->reg, uart->divisor);
+		break;
+#endif
+	default:
+		break;
+	}
+}
+
+static struct serial_device *get_console(void)
+{
+	if (decode_uart_console(gd->fdt_blob, &console_uart,
+			gd->baudrate))
+		return NULL;
+	strcpy(console.name, "serial");
+	console.init = fserial_init;
+	console.uninit = NULL;
+	console.setbrg = fserial_setbrg;
+	console.getc = fserial_getc;
+	console.tstc = fserial_tstc;
+	console.putc = fserial_putc;
+	console.puts = fserial_puts;
+	return &console;
+}
+
+struct serial_device *serial_fdt_get_console_f(void)
+{
+	/* if the uart isn't already set up, do it now */
+	if (console_uart.reg == -1U)
+		return get_console();
+
+	/* otherwise just return the current information */
+	return &console;
+}
+
+
+struct serial_device *serial_fdt_get_console_r(void)
+{
+	/*
+	 * Relocation moves all our function pointers, so we need to set up
+	 * things again. This function will only be called once.
+	 *
+	 * We cannot do the -1 check as in serial_fdt_get_console_f
+	 * because it will be -1 if that function has been ever been called.
+	 * However, the function pointers set up by serial_fdt_get_console_f
+	 * will be pre-relocation values, so we must re-calculate them.
+	 */
+	return get_console();
+}
diff --git a/include/fdtdec.h b/include/fdtdec.h
index d871cdd..e7e8d84 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -57,6 +57,7 @@  struct fdt_memory {
  */
 enum fdt_compat_id {
 	COMPAT_UNKNOWN,
+	COMPAT_SERIAL_NS16550,
 
 	COMPAT_COUNT,
 };
diff --git a/include/serial_fdt.h b/include/serial_fdt.h
new file mode 100644
index 0000000..c53e0a5
--- /dev/null
+++ b/include/serial_fdt.h
@@ -0,0 +1,36 @@ 
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+
+/*
+ * Provides a serial port defined by an FDT. This makes calls to the
+ * driver selected by the FDT.
+ */
+
+/**
+ * Return a pointer to the serial console device before relocation.
+ */
+struct serial_device *serial_fdt_get_console_f(void);
+
+/**
+ * Return a pointer to the serial console device after relocation.
+ */
+struct serial_device *serial_fdt_get_console_r(void);
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 0f87163..d9cb1ad 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -33,6 +33,7 @@  DECLARE_GLOBAL_DATA_PTR;
  */
 #define COMPAT(id, name) name
 static const char * const compat_names[COMPAT_COUNT] = {
+	COMPAT(SERIAL_NS16550, "ns16550"),
 };
 
 /**