drivers/tty/serial/8250/8250_of.c - linux-mtk - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  *  Serial Port driver for Open Firmware platform devices
  *
  *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
  */
 #include <linux/console.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/delay.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/pm_runtime.h>
 #include <linux/clk.h>
 #include <linux/reset.h>

 #include "8250.h"

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

 #ifdef CONFIG_ARCH_TEGRA
 static 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, irq;

 	memset(port, 0, sizeof *port);

 	pm_runtime_enable(&ofdev->dev);
 	pm_runtime_get_sync(&ofdev->dev);

 	if (of_property_read_u32(np, "clock-frequency", &clk)) {

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

 		ret = clk_prepare_enable(info->clk);
 		if (ret < 0)
 			goto err_pmruntime;

 		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 err_unprepare;
 	}

 	port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
 				  UPF_FIXED_TYPE;
 	spin_lock_init(&port->lock);

 	if (resource_type(&resource) == IORESOURCE_IO) {
 		port->iotype = UPIO_PORT;
 		port->iobase = resource.start;
 	} else {
 		port->mapbase = resource.start;
 		port->mapsize = resource_size(&resource);

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

 		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 2:
 				port->iotype = UPIO_MEM16;
 				break;
 			case 4:
 				port->iotype = of_device_is_big_endian(np) ?
 					       UPIO_MEM32BE : UPIO_MEM32;
 				break;
 			default:
 				dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 					 prop);
 				ret = -EINVAL;
 				goto err_unprepare;
 			}
 		}
 		port->flags |= UPF_IOREMAP;
 	}

 	/* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
 	if (of_device_is_compatible(np, "mrvl,mmp-uart"))
 		port->regshift = 2;

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

 	/* Check for fifo size */
 	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 		port->fifosize = prop;

 	/* Check for a fixed line number */
 	ret = of_alias_get_id(np, "serial");
 	if (ret >= 0)
 		port->line = ret;

 	irq = of_irq_get(np, 0);
 	if (irq < 0) {
 		if (irq == -EPROBE_DEFER) {
 			ret = -EPROBE_DEFER;
 			goto err_unprepare;
 		}
 		/* IRQ support not mandatory */
 		irq = 0;
 	}

 	port->irq = irq;

 	info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 	if (IS_ERR(info->rst)) {
 		ret = PTR_ERR(info->rst);
 		goto err_unprepare;
 	}

 	ret = reset_control_deassert(info->rst);
 	if (ret)
 		goto err_unprepare;

 	port->type = type;
 	port->uartclk = clk;

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

 	port->dev = &ofdev->dev;

 	switch (type) {
 	case PORT_TEGRA:
 		port->handle_break = tegra_serial_handle_break;
 		break;

 	case PORT_RT2880:
 		port->iotype = UPIO_AU;
 		break;
 	}

 	if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
 	    (of_device_is_compatible(np, "fsl,ns16550") ||
 	     of_device_is_compatible(np, "fsl,16550-FIFO64")))
 		port->handle_irq = fsl8250_handle_irq;

 	return 0;
 err_unprepare:
 	clk_disable_unprepare(info->clk);
 err_pmruntime:
 	pm_runtime_put_sync(&ofdev->dev);
 	pm_runtime_disable(&ofdev->dev);
 	return ret;
 }

 /*
  * Try to register a serial port
  */
 static const 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_8250_port port8250;
 	u32 tx_threshold;
 	int port_type;
 	int ret;

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

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

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

 	port_type = (unsigned long)match->data;
 	memset(&port8250, 0, sizeof(port8250));
 	ret = of_platform_serial_setup(ofdev, port_type, &port8250.port, info);
 	if (ret)
 		goto err_free;

 	if (port8250.port.fifosize)
 		port8250.capabilities = UART_CAP_FIFO;

 	/* Check for TX FIFO threshold & set tx_loadsz */
 	if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
 				  &tx_threshold) == 0) &&
 	    (tx_threshold < port8250.port.fifosize))
 		port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;

 	if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
 		port8250.capabilities |= UART_CAP_AFE;

 	if (of_property_read_u32(ofdev->dev.of_node,
 			"overrun-throttle-ms",
 			&port8250.overrun_backoff_time_ms) != 0)
 		port8250.overrun_backoff_time_ms = 0;

 	ret = serial8250_register_8250_port(&port8250);
 	if (ret < 0)
 		goto err_dispose;

 	info->type = port_type;
 	info->line = ret;
 	platform_set_drvdata(ofdev, info);
 	return 0;
 err_dispose:
 	irq_dispose_mapping(port8250.port.irq);
 	pm_runtime_put_sync(&ofdev->dev);
 	pm_runtime_disable(&ofdev->dev);
 	clk_disable_unprepare(info->clk);
 err_free:
 	kfree(info);
 	return ret;
 }

 /*
  * Release a line
  */
 static int of_platform_serial_remove(struct platform_device *ofdev)
 {
 	struct of_serial_info *info = platform_get_drvdata(ofdev);

 	serial8250_unregister_port(info->line);

 	reset_control_assert(info->rst);
 	pm_runtime_put_sync(&ofdev->dev);
 	pm_runtime_disable(&ofdev->dev);
 	clk_disable_unprepare(info->clk);
 	kfree(info);
 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP
 static int of_serial_suspend(struct device *dev)
 {
 	struct of_serial_info *info = dev_get_drvdata(dev);
 	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 	struct uart_port *port = &port8250->port;

 	serial8250_suspend_port(info->line);

 	if (!uart_console(port) || console_suspend_enabled) {
 		pm_runtime_put_sync(dev);
 		clk_disable_unprepare(info->clk);
 	}
 	return 0;
 }

 static int of_serial_resume(struct device *dev)
 {
 	struct of_serial_info *info = dev_get_drvdata(dev);
 	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 	struct uart_port *port = &port8250->port;

 	if (!uart_console(port) || console_suspend_enabled) {
 		pm_runtime_get_sync(dev);
 		clk_prepare_enable(info->clk);
 	}

 	serial8250_resume_port(info->line);

 	return 0;
 }
 #endif
 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);

 /*
  * A few common types, add more as needed.
  */
 static const 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 = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 	{ .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, },
 	{ .compatible = "mediatek,mtk-btif",
 		.data = (void *)PORT_MTK_BTIF, },
 	{ .compatible = "mrvl,mmp-uart",
 		.data = (void *)PORT_XSCALE, },
 	{ .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
 	{ .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
 	{ /* end of list */ },
 };
 MODULE_DEVICE_TABLE(of, of_platform_serial_table);

 static struct platform_driver of_platform_serial_driver = {
 	.driver = {
 		.name = "of_serial",
 		.of_match_table = of_platform_serial_table,
 		.pm = &of_serial_pm_ops,
 	},
 	.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");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Serial Port driver for Open Firmware platform devices
	*
	* Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
	*/
	#include <linux/console.h>
	#include <linux/module.h>
	#include <linux/slab.h>
	#include <linux/delay.h>
	#include <linux/serial_core.h>
	#include <linux/serial_reg.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>
	#include <linux/pm_runtime.h>
	#include <linux/clk.h>
	#include <linux/reset.h>

	#include "8250.h"

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

	#ifdef CONFIG_ARCH_TEGRA
	static 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, irq;

	memset(port, 0, sizeof *port);

	pm_runtime_enable(&ofdev->dev);
	pm_runtime_get_sync(&ofdev->dev);

	if (of_property_read_u32(np, "clock-frequency", &clk)) {

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

	ret = clk_prepare_enable(info->clk);
	if (ret < 0)
	goto err_pmruntime;

	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 err_unprepare;
	}

	port->flags = UPF_SHARE_IRQ \| UPF_BOOT_AUTOCONF \| UPF_FIXED_PORT \|
	UPF_FIXED_TYPE;
	spin_lock_init(&port->lock);

	if (resource_type(&resource) == IORESOURCE_IO) {
	port->iotype = UPIO_PORT;
	port->iobase = resource.start;
	} else {
	port->mapbase = resource.start;
	port->mapsize = resource_size(&resource);

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

	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 2:
	port->iotype = UPIO_MEM16;
	break;
	case 4:
	port->iotype = of_device_is_big_endian(np) ?
	UPIO_MEM32BE : UPIO_MEM32;
	break;
	default:
	dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
	prop);
	ret = -EINVAL;
	goto err_unprepare;
	}
	}
	port->flags \|= UPF_IOREMAP;
	}

	/* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
	if (of_device_is_compatible(np, "mrvl,mmp-uart"))
	port->regshift = 2;

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

	/* Check for fifo size */
	if (of_property_read_u32(np, "fifo-size", &prop) == 0)
	port->fifosize = prop;

	/* Check for a fixed line number */
	ret = of_alias_get_id(np, "serial");
	if (ret >= 0)
	port->line = ret;

	irq = of_irq_get(np, 0);
	if (irq < 0) {
	if (irq == -EPROBE_DEFER) {
	ret = -EPROBE_DEFER;
	goto err_unprepare;
	}
	/* IRQ support not mandatory */
	irq = 0;
	}

	port->irq = irq;

	info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
	if (IS_ERR(info->rst)) {
	ret = PTR_ERR(info->rst);
	goto err_unprepare;
	}

	ret = reset_control_deassert(info->rst);
	if (ret)
	goto err_unprepare;

	port->type = type;
	port->uartclk = clk;

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

	port->dev = &ofdev->dev;

	switch (type) {
	case PORT_TEGRA:
	port->handle_break = tegra_serial_handle_break;
	break;

	case PORT_RT2880:
	port->iotype = UPIO_AU;
	break;
	}

	if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
	(of_device_is_compatible(np, "fsl,ns16550") \|\|
	of_device_is_compatible(np, "fsl,16550-FIFO64")))
	port->handle_irq = fsl8250_handle_irq;

	return 0;
	err_unprepare:
	clk_disable_unprepare(info->clk);
	err_pmruntime:
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	return ret;
	}

	/*
	* Try to register a serial port
	*/
	static const 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_8250_port port8250;
	u32 tx_threshold;
	int port_type;
	int ret;

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

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

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

	port_type = (unsigned long)match->data;
	memset(&port8250, 0, sizeof(port8250));
	ret = of_platform_serial_setup(ofdev, port_type, &port8250.port, info);
	if (ret)
	goto err_free;

	if (port8250.port.fifosize)
	port8250.capabilities = UART_CAP_FIFO;

	/* Check for TX FIFO threshold & set tx_loadsz */
	if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
	&tx_threshold) == 0) &&
	(tx_threshold < port8250.port.fifosize))
	port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;

	if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
	port8250.capabilities \|= UART_CAP_AFE;

	if (of_property_read_u32(ofdev->dev.of_node,
	"overrun-throttle-ms",
	&port8250.overrun_backoff_time_ms) != 0)
	port8250.overrun_backoff_time_ms = 0;

	ret = serial8250_register_8250_port(&port8250);
	if (ret < 0)
	goto err_dispose;

	info->type = port_type;
	info->line = ret;
	platform_set_drvdata(ofdev, info);
	return 0;
	err_dispose:
	irq_dispose_mapping(port8250.port.irq);
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	clk_disable_unprepare(info->clk);
	err_free:
	kfree(info);
	return ret;
	}

	/*
	* Release a line
	*/
	static int of_platform_serial_remove(struct platform_device *ofdev)
	{
	struct of_serial_info *info = platform_get_drvdata(ofdev);

	serial8250_unregister_port(info->line);

	reset_control_assert(info->rst);
	pm_runtime_put_sync(&ofdev->dev);
	pm_runtime_disable(&ofdev->dev);
	clk_disable_unprepare(info->clk);
	kfree(info);
	return 0;
	}

	#ifdef CONFIG_PM_SLEEP
	static int of_serial_suspend(struct device *dev)
	{
	struct of_serial_info *info = dev_get_drvdata(dev);
	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
	struct uart_port *port = &port8250->port;

	serial8250_suspend_port(info->line);

	if (!uart_console(port) \|\| console_suspend_enabled) {
	pm_runtime_put_sync(dev);
	clk_disable_unprepare(info->clk);
	}
	return 0;
	}

	static int of_serial_resume(struct device *dev)
	{
	struct of_serial_info *info = dev_get_drvdata(dev);
	struct uart_8250_port *port8250 = serial8250_get_port(info->line);
	struct uart_port *port = &port8250->port;

	if (!uart_console(port) \|\| console_suspend_enabled) {
	pm_runtime_get_sync(dev);
	clk_prepare_enable(info->clk);
	}

	serial8250_resume_port(info->line);

	return 0;
	}
	#endif
	static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);

	/*
	* A few common types, add more as needed.
	*/
	static const 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 = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
	{ .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, },
	{ .compatible = "mediatek,mtk-btif",
	.data = (void *)PORT_MTK_BTIF, },
	{ .compatible = "mrvl,mmp-uart",
	.data = (void *)PORT_XSCALE, },
	{ .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
	{ .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
	{ /* end of list */ },
	};
	MODULE_DEVICE_TABLE(of, of_platform_serial_table);

	static struct platform_driver of_platform_serial_driver = {
	.driver = {
	.name = "of_serial",
	.of_match_table = of_platform_serial_table,
	.pm = &of_serial_pm_ops,
	},
	.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");