drivers/tty/serial/of_serial.c - linux - Git at Google

 /*
  *  Serial Port driver for Open Firmware platform devices
  *
  *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
  *
  *  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.
  *
  */
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/serial_core.h>
 #include <linux/serial_8250.h>
 #include <linux/serial_reg.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/nwpserial.h>
 #include <linux/clk.h>

 struct of_serial_info {
 	struct clk *clk;
 	int type;
 	int line;
 };

 #ifdef CONFIG_ARCH_TEGRA
 void tegra_serial_handle_break(struct uart_port *p)
 {
 	unsigned int status, tmout = 10000;

 	do {
 		status = p->serial_in(p, UART_LSR);
 		if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
 			status = p->serial_in(p, UART_RX);
 		else
 			break;
 		if (--tmout == 0)
 			break;
 		udelay(1);
 	} while (1);
 }
 #else
 static inline void tegra_serial_handle_break(struct uart_port *port)
 {
 }
 #endif

 /*
  * Fill a struct uart_port for a given device node
  */
 static int of_platform_serial_setup(struct platform_device *ofdev,
 			int type, struct uart_port *port,
 			struct of_serial_info *info)
 {
 	struct resource resource;
 	struct device_node *np = ofdev->dev.of_node;
 	u32 clk, spd, prop;
 	int ret;

 	memset(port, 0, sizeof *port);
 	if (of_property_read_u32(np, "clock-frequency", &clk)) {

 		/* Get clk rate through clk driver if present */
 		info->clk = clk_get(&ofdev->dev, NULL);
 		if (IS_ERR(info->clk)) {
 			dev_warn(&ofdev->dev,
 				"clk or clock-frequency not defined\n");
 			return PTR_ERR(info->clk);
 		}

 		clk_prepare_enable(info->clk);
 		clk = clk_get_rate(info->clk);
 	}
 	/* If current-speed was set, then try not to change it. */
 	if (of_property_read_u32(np, "current-speed", &spd) == 0)
 		port->custom_divisor = clk / (16 * spd);

 	ret = of_address_to_resource(np, 0, &resource);
 	if (ret) {
 		dev_warn(&ofdev->dev, "invalid address\n");
 		goto out;
 	}

 	spin_lock_init(&port->lock);
 	port->mapbase = resource.start;

 	/* Check for shifted address mapping */
 	if (of_property_read_u32(np, "reg-offset", &prop) == 0)
 		port->mapbase += prop;

 	/* Check for registers offset within the devices address range */
 	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 		port->regshift = prop;

 	port->irq = irq_of_parse_and_map(np, 0);
 	port->iotype = UPIO_MEM;
 	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 		switch (prop) {
 		case 1:
 			port->iotype = UPIO_MEM;
 			break;
 		case 4:
 			port->iotype = UPIO_MEM32;
 			break;
 		default:
 			dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 				 prop);
 			ret = -EINVAL;
 			goto out;
 		}
 	}

 	port->type = type;
 	port->uartclk = clk;
 	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 		| UPF_FIXED_PORT | UPF_FIXED_TYPE;

 	if (of_find_property(np, "no-loopback-test", NULL))
 		port->flags |= UPF_SKIP_TEST;

 	port->dev = &ofdev->dev;

 	if (type == PORT_TEGRA)
 		port->handle_break = tegra_serial_handle_break;

 	return 0;
 out:
 	if (info->clk)
 		clk_disable_unprepare(info->clk);
 	return ret;
 }

 /*
  * Try to register a serial port
  */
 static struct of_device_id of_platform_serial_table[];
 static int of_platform_serial_probe(struct platform_device *ofdev)
 {
 	const struct of_device_id *match;
 	struct of_serial_info *info;
 	struct uart_port port;
 	int port_type;
 	int ret;

 	match = of_match_device(of_platform_serial_table, &ofdev->dev);
 	if (!match)
 		return -EINVAL;

 	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 		return -EBUSY;

 	info = kmalloc(sizeof(*info), GFP_KERNEL);
 	if (info == NULL)
 		return -ENOMEM;

 	port_type = (unsigned long)match->data;
 	ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 	if (ret)
 		goto out;

 	switch (port_type) {
 #ifdef CONFIG_SERIAL_8250
 	case PORT_8250 ... PORT_MAX_8250:
 	{
 		/* For now the of bindings don't support the extra
 		   8250 specific bits */
 		struct uart_8250_port port8250;
 		memset(&port8250, 0, sizeof(port8250));
 		port8250.port = port;
 		ret = serial8250_register_8250_port(&port8250);
 		break;
 	}
 #endif
 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 	case PORT_NWPSERIAL:
 		ret = nwpserial_register_port(&port);
 		break;
 #endif
 	default:
 		/* need to add code for these */
 	case PORT_UNKNOWN:
 		dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 		ret = -ENODEV;
 		break;
 	}
 	if (ret < 0)
 		goto out;

 	info->type = port_type;
 	info->line = ret;
 	dev_set_drvdata(&ofdev->dev, info);
 	return 0;
 out:
 	kfree(info);
 	irq_dispose_mapping(port.irq);
 	return ret;
 }

 /*
  * Release a line
  */
 static int of_platform_serial_remove(struct platform_device *ofdev)
 {
 	struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 	switch (info->type) {
 #ifdef CONFIG_SERIAL_8250
 	case PORT_8250 ... PORT_MAX_8250:
 		serial8250_unregister_port(info->line);
 		break;
 #endif
 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 	case PORT_NWPSERIAL:
 		nwpserial_unregister_port(info->line);
 		break;
 #endif
 	default:
 		/* need to add code for these */
 		break;
 	}

 	if (info->clk)
 		clk_disable_unprepare(info->clk);
 	kfree(info);
 	return 0;
 }

 /*
  * A few common types, add more as needed.
  */
 static struct of_device_id of_platform_serial_table[] = {
 	{ .compatible = "ns8250",   .data = (void *)PORT_8250, },
 	{ .compatible = "ns16450",  .data = (void *)PORT_16450, },
 	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 	{ .compatible = "ns16550",  .data = (void *)PORT_16550, },
 	{ .compatible = "ns16750",  .data = (void *)PORT_16750, },
 	{ .compatible = "ns16850",  .data = (void *)PORT_16850, },
 	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 	{ .compatible = "altr,16550-FIFO32",
 		.data = (void *)PORT_ALTR_16550_F32, },
 	{ .compatible = "altr,16550-FIFO64",
 		.data = (void *)PORT_ALTR_16550_F64, },
 	{ .compatible = "altr,16550-FIFO128",
 		.data = (void *)PORT_ALTR_16550_F128, },
 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 	{ .compatible = "ibm,qpace-nwp-serial",
 		.data = (void *)PORT_NWPSERIAL, },
 #endif
 	{ .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 	{ /* end of list */ },
 };

 static struct platform_driver of_platform_serial_driver = {
 	.driver = {
 		.name = "of_serial",
 		.owner = THIS_MODULE,
 		.of_match_table = of_platform_serial_table,
 	},
 	.probe = of_platform_serial_probe,
 	.remove = of_platform_serial_remove,
 };

 module_platform_driver(of_platform_serial_driver);

 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
	/*
	* Serial Port driver for Open Firmware platform devices
	*
	* Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
	*
	* 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.
	*
	*/
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/serial_core.h>
	#include <linux/serial_8250.h>
	#include <linux/serial_reg.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>
	#include <linux/nwpserial.h>
	#include <linux/clk.h>

	struct of_serial_info {
	struct clk *clk;
	int type;
	int line;
	};

	#ifdef CONFIG_ARCH_TEGRA
	void tegra_serial_handle_break(struct uart_port *p)
	{
	unsigned int status, tmout = 10000;

	do {
	status = p->serial_in(p, UART_LSR);
	if (status & (UART_LSR_FIFOE \| UART_LSR_BRK_ERROR_BITS))
	status = p->serial_in(p, UART_RX);
	else
	break;
	if (--tmout == 0)
	break;
	udelay(1);
	} while (1);
	}
	#else
	static inline void tegra_serial_handle_break(struct uart_port *port)
	{
	}
	#endif

	/*
	* Fill a struct uart_port for a given device node
	*/
	static int of_platform_serial_setup(struct platform_device *ofdev,
	int type, struct uart_port *port,
	struct of_serial_info *info)
	{
	struct resource resource;
	struct device_node *np = ofdev->dev.of_node;
	u32 clk, spd, prop;
	int ret;

	memset(port, 0, sizeof *port);
	if (of_property_read_u32(np, "clock-frequency", &clk)) {

	/* Get clk rate through clk driver if present */
	info->clk = clk_get(&ofdev->dev, NULL);
	if (IS_ERR(info->clk)) {
	dev_warn(&ofdev->dev,
	"clk or clock-frequency not defined\n");
	return PTR_ERR(info->clk);
	}

	clk_prepare_enable(info->clk);
	clk = clk_get_rate(info->clk);
	}
	/* If current-speed was set, then try not to change it. */
	if (of_property_read_u32(np, "current-speed", &spd) == 0)
	port->custom_divisor = clk / (16 * spd);

	ret = of_address_to_resource(np, 0, &resource);
	if (ret) {
	dev_warn(&ofdev->dev, "invalid address\n");
	goto out;
	}

	spin_lock_init(&port->lock);
	port->mapbase = resource.start;

	/* Check for shifted address mapping */
	if (of_property_read_u32(np, "reg-offset", &prop) == 0)
	port->mapbase += prop;

	/* Check for registers offset within the devices address range */
	if (of_property_read_u32(np, "reg-shift", &prop) == 0)
	port->regshift = prop;

	port->irq = irq_of_parse_and_map(np, 0);
	port->iotype = UPIO_MEM;
	if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
	switch (prop) {
	case 1:
	port->iotype = UPIO_MEM;
	break;
	case 4:
	port->iotype = UPIO_MEM32;
	break;
	default:
	dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
	prop);
	ret = -EINVAL;
	goto out;
	}
	}

	port->type = type;
	port->uartclk = clk;
	port->flags = UPF_SHARE_IRQ \| UPF_BOOT_AUTOCONF \| UPF_IOREMAP
	\| UPF_FIXED_PORT \| UPF_FIXED_TYPE;

	if (of_find_property(np, "no-loopback-test", NULL))
	port->flags \|= UPF_SKIP_TEST;

	port->dev = &ofdev->dev;

	if (type == PORT_TEGRA)
	port->handle_break = tegra_serial_handle_break;

	return 0;
	out:
	if (info->clk)
	clk_disable_unprepare(info->clk);
	return ret;
	}

	/*
	* Try to register a serial port
	*/
	static struct of_device_id of_platform_serial_table[];
	static int of_platform_serial_probe(struct platform_device *ofdev)
	{
	const struct of_device_id *match;
	struct of_serial_info *info;
	struct uart_port port;
	int port_type;
	int ret;

	match = of_match_device(of_platform_serial_table, &ofdev->dev);
	if (!match)
	return -EINVAL;

	if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
	return -EBUSY;

	info = kmalloc(sizeof(*info), GFP_KERNEL);
	if (info == NULL)
	return -ENOMEM;

	port_type = (unsigned long)match->data;
	ret = of_platform_serial_setup(ofdev, port_type, &port, info);
	if (ret)
	goto out;

	switch (port_type) {
	#ifdef CONFIG_SERIAL_8250
	case PORT_8250 ... PORT_MAX_8250:
	{
	/* For now the of bindings don't support the extra
	8250 specific bits */
	struct uart_8250_port port8250;
	memset(&port8250, 0, sizeof(port8250));
	port8250.port = port;
	ret = serial8250_register_8250_port(&port8250);
	break;
	}
	#endif
	#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
	case PORT_NWPSERIAL:
	ret = nwpserial_register_port(&port);
	break;
	#endif
	default:
	/* need to add code for these */
	case PORT_UNKNOWN:
	dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
	ret = -ENODEV;
	break;
	}
	if (ret < 0)
	goto out;

	info->type = port_type;
	info->line = ret;
	dev_set_drvdata(&ofdev->dev, info);
	return 0;
	out:
	kfree(info);
	irq_dispose_mapping(port.irq);
	return ret;
	}

	/*
	* Release a line
	*/
	static int of_platform_serial_remove(struct platform_device *ofdev)
	{
	struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
	switch (info->type) {
	#ifdef CONFIG_SERIAL_8250
	case PORT_8250 ... PORT_MAX_8250:
	serial8250_unregister_port(info->line);
	break;
	#endif
	#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
	case PORT_NWPSERIAL:
	nwpserial_unregister_port(info->line);
	break;
	#endif
	default:
	/* need to add code for these */
	break;
	}

	if (info->clk)
	clk_disable_unprepare(info->clk);
	kfree(info);
	return 0;
	}

	/*
	* A few common types, add more as needed.
	*/
	static struct of_device_id of_platform_serial_table[] = {
	{ .compatible = "ns8250", .data = (void *)PORT_8250, },
	{ .compatible = "ns16450", .data = (void *)PORT_16450, },
	{ .compatible = "ns16550a", .data = (void *)PORT_16550A, },
	{ .compatible = "ns16550", .data = (void *)PORT_16550, },
	{ .compatible = "ns16750", .data = (void *)PORT_16750, },
	{ .compatible = "ns16850", .data = (void *)PORT_16850, },
	{ .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
	{ .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
	{ .compatible = "altr,16550-FIFO32",
	.data = (void *)PORT_ALTR_16550_F32, },
	{ .compatible = "altr,16550-FIFO64",
	.data = (void *)PORT_ALTR_16550_F64, },
	{ .compatible = "altr,16550-FIFO128",
	.data = (void *)PORT_ALTR_16550_F128, },
	#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
	{ .compatible = "ibm,qpace-nwp-serial",
	.data = (void *)PORT_NWPSERIAL, },
	#endif
	{ .type = "serial", .data = (void *)PORT_UNKNOWN, },
	{ /* end of list */ },
	};

	static struct platform_driver of_platform_serial_driver = {
	.driver = {
	.name = "of_serial",
	.owner = THIS_MODULE,
	.of_match_table = of_platform_serial_table,
	},
	.probe = of_platform_serial_probe,
	.remove = of_platform_serial_remove,
	};

	module_platform_driver(of_platform_serial_driver);

	MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");