drivers/tty/serial/8250/8250_aspeed_vuart.c - manifest_repos/valens - Git at Google

 /*
  *  Serial Port driver for Aspeed VUART device
  *
  *    Copyright (C) 2016 Jeremy Kerr <jk@ozlabs.org>, IBM Corp.
  *    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/device.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/clk.h>

 #include "8250.h"

 #define ASPEED_VUART_GCRA		0x20
 #define ASPEED_VUART_GCRA_VUART_EN		BIT(0)
 #define ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD BIT(5)
 #define ASPEED_VUART_GCRB		0x24
 #define ASPEED_VUART_GCRB_HOST_SIRQ_MASK	GENMASK(7, 4)
 #define ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT	4
 #define ASPEED_VUART_ADDRL		0x28
 #define ASPEED_VUART_ADDRH		0x2c

 struct aspeed_vuart {
 	struct device		*dev;
 	void __iomem		*regs;
 	struct clk		*clk;
 	int			line;
 };

 /*
  * The VUART is basically two UART 'front ends' connected by their FIFO
  * (no actual serial line in between). One is on the BMC side (management
  * controller) and one is on the host CPU side.
  *
  * It allows the BMC to provide to the host a "UART" that pipes into
  * the BMC itself and can then be turned by the BMC into a network console
  * of some sort for example.
  *
  * This driver is for the BMC side. The sysfs files allow the BMC
  * userspace which owns the system configuration policy, to specify
  * at what IO port and interrupt number the host side will appear
  * to the host on the Host <-> BMC LPC bus. It could be different on a
  * different system (though most of them use 3f8/4).
  */

 static ssize_t lpc_address_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
 	u16 addr;

 	addr = (readb(vuart->regs + ASPEED_VUART_ADDRH) << 8) |
 		(readb(vuart->regs + ASPEED_VUART_ADDRL));

 	return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
 }

 static ssize_t lpc_address_store(struct device *dev,
 				 struct device_attribute *attr,
 				 const char *buf, size_t count)
 {
 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
 	unsigned long val;
 	int err;

 	err = kstrtoul(buf, 0, &val);
 	if (err)
 		return err;

 	writeb(val >> 8, vuart->regs + ASPEED_VUART_ADDRH);
 	writeb(val >> 0, vuart->regs + ASPEED_VUART_ADDRL);

 	return count;
 }

 static DEVICE_ATTR_RW(lpc_address);

 static ssize_t sirq_show(struct device *dev,
 			 struct device_attribute *attr, char *buf)
 {
 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
 	u8 reg;

 	reg = readb(vuart->regs + ASPEED_VUART_GCRB);
 	reg &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
 	reg >>= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;

 	return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg);
 }

 static ssize_t sirq_store(struct device *dev, struct device_attribute *attr,
 			  const char *buf, size_t count)
 {
 	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
 	unsigned long val;
 	int err;
 	u8 reg;

 	err = kstrtoul(buf, 0, &val);
 	if (err)
 		return err;

 	val <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;
 	val &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;

 	reg = readb(vuart->regs + ASPEED_VUART_GCRB);
 	reg &= ~ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
 	reg |= val;
 	writeb(reg, vuart->regs + ASPEED_VUART_GCRB);

 	return count;
 }

 static DEVICE_ATTR_RW(sirq);

 static struct attribute *aspeed_vuart_attrs[] = {
 	&dev_attr_sirq.attr,
 	&dev_attr_lpc_address.attr,
 	NULL,
 };

 static const struct attribute_group aspeed_vuart_attr_group = {
 	.attrs = aspeed_vuart_attrs,
 };

 static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled)
 {
 	u8 reg = readb(vuart->regs + ASPEED_VUART_GCRA);

 	if (enabled)
 		reg |= ASPEED_VUART_GCRA_VUART_EN;
 	else
 		reg &= ~ASPEED_VUART_GCRA_VUART_EN;

 	writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
 }

 static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart,
 					     bool discard)
 {
 	u8 reg;

 	reg = readb(vuart->regs + ASPEED_VUART_GCRA);

 	/* If the DISABLE_HOST_TX_DISCARD bit is set, discard is disabled */
 	if (!discard)
 		reg |= ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;
 	else
 		reg &= ~ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;

 	writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
 }

 static int aspeed_vuart_startup(struct uart_port *uart_port)
 {
 	struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;
 	int rc;

 	rc = serial8250_do_startup(uart_port);
 	if (rc)
 		return rc;

 	aspeed_vuart_set_host_tx_discard(vuart, false);

 	return 0;
 }

 static void aspeed_vuart_shutdown(struct uart_port *uart_port)
 {
 	struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
 	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;

 	aspeed_vuart_set_host_tx_discard(vuart, true);

 	serial8250_do_shutdown(uart_port);
 }

 static int aspeed_vuart_probe(struct platform_device *pdev)
 {
 	struct uart_8250_port port;
 	struct aspeed_vuart *vuart;
 	struct device_node *np;
 	struct resource *res;
 	u32 clk, prop;
 	int rc;

 	np = pdev->dev.of_node;

 	vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL);
 	if (!vuart)
 		return -ENOMEM;

 	vuart->dev = &pdev->dev;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	vuart->regs = devm_ioremap_resource(&pdev->dev, res);
 	if (IS_ERR(vuart->regs))
 		return PTR_ERR(vuart->regs);

 	memset(&port, 0, sizeof(port));
 	port.port.private_data = vuart;
 	port.port.membase = vuart->regs;
 	port.port.mapbase = res->start;
 	port.port.mapsize = resource_size(res);
 	port.port.startup = aspeed_vuart_startup;
 	port.port.shutdown = aspeed_vuart_shutdown;
 	port.port.dev = &pdev->dev;

 	rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
 	if (rc < 0)
 		return rc;

 	if (of_property_read_u32(np, "clock-frequency", &clk)) {
 		vuart->clk = devm_clk_get(&pdev->dev, NULL);
 		if (IS_ERR(vuart->clk)) {
 			dev_warn(&pdev->dev,
 				"clk or clock-frequency not defined\n");
 			rc = PTR_ERR(vuart->clk);
 			goto err_sysfs_remove;
 		}

 		rc = clk_prepare_enable(vuart->clk);
 		if (rc < 0)
 			goto err_sysfs_remove;

 		clk = clk_get_rate(vuart->clk);
 	}

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

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

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

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

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

 	port.port.irq = irq_of_parse_and_map(np, 0);
 	port.port.iotype = UPIO_MEM;
 	port.port.type = PORT_16550A;
 	port.port.uartclk = clk;
 	port.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF
 		| UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_NO_THRE_TEST;

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

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

 	if (of_property_read_bool(np, "auto-flow-control"))
 		port.capabilities |= UART_CAP_AFE;

 	rc = serial8250_register_8250_port(&port);
 	if (rc < 0)
 		goto err_clk_disable;

 	vuart->line = rc;

 	aspeed_vuart_set_enabled(vuart, true);
 	aspeed_vuart_set_host_tx_discard(vuart, true);
 	platform_set_drvdata(pdev, vuart);

 	return 0;

 err_clk_disable:
 	clk_disable_unprepare(vuart->clk);
 	irq_dispose_mapping(port.port.irq);
 err_sysfs_remove:
 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
 	return rc;
 }

 static int aspeed_vuart_remove(struct platform_device *pdev)
 {
 	struct aspeed_vuart *vuart = platform_get_drvdata(pdev);

 	aspeed_vuart_set_enabled(vuart, false);
 	serial8250_unregister_port(vuart->line);
 	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
 	clk_disable_unprepare(vuart->clk);

 	return 0;
 }

 static const struct of_device_id aspeed_vuart_table[] = {
 	{ .compatible = "aspeed,ast2400-vuart" },
 	{ .compatible = "aspeed,ast2500-vuart" },
 	{ },
 };

 static struct platform_driver aspeed_vuart_driver = {
 	.driver = {
 		.name = "aspeed-vuart",
 		.of_match_table = aspeed_vuart_table,
 	},
 	.probe = aspeed_vuart_probe,
 	.remove = aspeed_vuart_remove,
 };

 module_platform_driver(aspeed_vuart_driver);

 MODULE_AUTHOR("Jeremy Kerr <jk@ozlabs.org>");
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Driver for Aspeed VUART device");
	/*
	* Serial Port driver for Aspeed VUART device
	*
	* Copyright (C) 2016 Jeremy Kerr <jk@ozlabs.org>, IBM Corp.
	* 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/device.h>
	#include <linux/module.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/of_platform.h>
	#include <linux/clk.h>

	#include "8250.h"

	#define ASPEED_VUART_GCRA 0x20
	#define ASPEED_VUART_GCRA_VUART_EN BIT(0)
	#define ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD BIT(5)
	#define ASPEED_VUART_GCRB 0x24
	#define ASPEED_VUART_GCRB_HOST_SIRQ_MASK GENMASK(7, 4)
	#define ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT 4
	#define ASPEED_VUART_ADDRL 0x28
	#define ASPEED_VUART_ADDRH 0x2c

	struct aspeed_vuart {
	struct device *dev;
	void __iomem *regs;
	struct clk *clk;
	int line;
	};

	/*
	* The VUART is basically two UART 'front ends' connected by their FIFO
	* (no actual serial line in between). One is on the BMC side (management
	* controller) and one is on the host CPU side.
	*
	* It allows the BMC to provide to the host a "UART" that pipes into
	* the BMC itself and can then be turned by the BMC into a network console
	* of some sort for example.
	*
	* This driver is for the BMC side. The sysfs files allow the BMC
	* userspace which owns the system configuration policy, to specify
	* at what IO port and interrupt number the host side will appear
	* to the host on the Host <-> BMC LPC bus. It could be different on a
	* different system (though most of them use 3f8/4).
	*/

	static ssize_t lpc_address_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
	u16 addr;

	addr = (readb(vuart->regs + ASPEED_VUART_ADDRH) << 8) \|
	(readb(vuart->regs + ASPEED_VUART_ADDRL));

	return snprintf(buf, PAGE_SIZE - 1, "0x%x\n", addr);
	}

	static ssize_t lpc_address_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t count)
	{
	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
	unsigned long val;
	int err;

	err = kstrtoul(buf, 0, &val);
	if (err)
	return err;

	writeb(val >> 8, vuart->regs + ASPEED_VUART_ADDRH);
	writeb(val >> 0, vuart->regs + ASPEED_VUART_ADDRL);

	return count;
	}

	static DEVICE_ATTR_RW(lpc_address);

	static ssize_t sirq_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
	u8 reg;

	reg = readb(vuart->regs + ASPEED_VUART_GCRB);
	reg &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
	reg >>= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;

	return snprintf(buf, PAGE_SIZE - 1, "%u\n", reg);
	}

	static ssize_t sirq_store(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct aspeed_vuart *vuart = dev_get_drvdata(dev);
	unsigned long val;
	int err;
	u8 reg;

	err = kstrtoul(buf, 0, &val);
	if (err)
	return err;

	val <<= ASPEED_VUART_GCRB_HOST_SIRQ_SHIFT;
	val &= ASPEED_VUART_GCRB_HOST_SIRQ_MASK;

	reg = readb(vuart->regs + ASPEED_VUART_GCRB);
	reg &= ~ASPEED_VUART_GCRB_HOST_SIRQ_MASK;
	reg \|= val;
	writeb(reg, vuart->regs + ASPEED_VUART_GCRB);

	return count;
	}

	static DEVICE_ATTR_RW(sirq);

	static struct attribute *aspeed_vuart_attrs[] = {
	&dev_attr_sirq.attr,
	&dev_attr_lpc_address.attr,
	NULL,
	};

	static const struct attribute_group aspeed_vuart_attr_group = {
	.attrs = aspeed_vuart_attrs,
	};

	static void aspeed_vuart_set_enabled(struct aspeed_vuart *vuart, bool enabled)
	{
	u8 reg = readb(vuart->regs + ASPEED_VUART_GCRA);

	if (enabled)
	reg \|= ASPEED_VUART_GCRA_VUART_EN;
	else
	reg &= ~ASPEED_VUART_GCRA_VUART_EN;

	writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
	}

	static void aspeed_vuart_set_host_tx_discard(struct aspeed_vuart *vuart,
	bool discard)
	{
	u8 reg;

	reg = readb(vuart->regs + ASPEED_VUART_GCRA);

	/* If the DISABLE_HOST_TX_DISCARD bit is set, discard is disabled */
	if (!discard)
	reg \|= ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;
	else
	reg &= ~ASPEED_VUART_GCRA_DISABLE_HOST_TX_DISCARD;

	writeb(reg, vuart->regs + ASPEED_VUART_GCRA);
	}

	static int aspeed_vuart_startup(struct uart_port *uart_port)
	{
	struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;
	int rc;

	rc = serial8250_do_startup(uart_port);
	if (rc)
	return rc;

	aspeed_vuart_set_host_tx_discard(vuart, false);

	return 0;
	}

	static void aspeed_vuart_shutdown(struct uart_port *uart_port)
	{
	struct uart_8250_port *uart_8250_port = up_to_u8250p(uart_port);
	struct aspeed_vuart *vuart = uart_8250_port->port.private_data;

	aspeed_vuart_set_host_tx_discard(vuart, true);

	serial8250_do_shutdown(uart_port);
	}

	static int aspeed_vuart_probe(struct platform_device *pdev)
	{
	struct uart_8250_port port;
	struct aspeed_vuart *vuart;
	struct device_node *np;
	struct resource *res;
	u32 clk, prop;
	int rc;

	np = pdev->dev.of_node;

	vuart = devm_kzalloc(&pdev->dev, sizeof(*vuart), GFP_KERNEL);
	if (!vuart)
	return -ENOMEM;

	vuart->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	vuart->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(vuart->regs))
	return PTR_ERR(vuart->regs);

	memset(&port, 0, sizeof(port));
	port.port.private_data = vuart;
	port.port.membase = vuart->regs;
	port.port.mapbase = res->start;
	port.port.mapsize = resource_size(res);
	port.port.startup = aspeed_vuart_startup;
	port.port.shutdown = aspeed_vuart_shutdown;
	port.port.dev = &pdev->dev;

	rc = sysfs_create_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
	if (rc < 0)
	return rc;

	if (of_property_read_u32(np, "clock-frequency", &clk)) {
	vuart->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(vuart->clk)) {
	dev_warn(&pdev->dev,
	"clk or clock-frequency not defined\n");
	rc = PTR_ERR(vuart->clk);
	goto err_sysfs_remove;
	}

	rc = clk_prepare_enable(vuart->clk);
	if (rc < 0)
	goto err_sysfs_remove;

	clk = clk_get_rate(vuart->clk);
	}

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

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

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

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

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

	port.port.irq = irq_of_parse_and_map(np, 0);
	port.port.iotype = UPIO_MEM;
	port.port.type = PORT_16550A;
	port.port.uartclk = clk;
	port.port.flags = UPF_SHARE_IRQ \| UPF_BOOT_AUTOCONF
	\| UPF_FIXED_PORT \| UPF_FIXED_TYPE \| UPF_NO_THRE_TEST;

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

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

	if (of_property_read_bool(np, "auto-flow-control"))
	port.capabilities \|= UART_CAP_AFE;

	rc = serial8250_register_8250_port(&port);
	if (rc < 0)
	goto err_clk_disable;

	vuart->line = rc;

	aspeed_vuart_set_enabled(vuart, true);
	aspeed_vuart_set_host_tx_discard(vuart, true);
	platform_set_drvdata(pdev, vuart);

	return 0;

	err_clk_disable:
	clk_disable_unprepare(vuart->clk);
	irq_dispose_mapping(port.port.irq);
	err_sysfs_remove:
	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
	return rc;
	}

	static int aspeed_vuart_remove(struct platform_device *pdev)
	{
	struct aspeed_vuart *vuart = platform_get_drvdata(pdev);

	aspeed_vuart_set_enabled(vuart, false);
	serial8250_unregister_port(vuart->line);
	sysfs_remove_group(&vuart->dev->kobj, &aspeed_vuart_attr_group);
	clk_disable_unprepare(vuart->clk);

	return 0;
	}

	static const struct of_device_id aspeed_vuart_table[] = {
	{ .compatible = "aspeed,ast2400-vuart" },
	{ .compatible = "aspeed,ast2500-vuart" },
	{ },
	};

	static struct platform_driver aspeed_vuart_driver = {
	.driver = {
	.name = "aspeed-vuart",
	.of_match_table = aspeed_vuart_table,
	},
	.probe = aspeed_vuart_probe,
	.remove = aspeed_vuart_remove,
	};

	module_platform_driver(aspeed_vuart_driver);

	MODULE_AUTHOR("Jeremy Kerr <jk@ozlabs.org>");
	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("Driver for Aspeed VUART device");