4 files changed, 668 insertions, 0 deletions
diff --git a/drivers/tty/serdev/Kconfig b/drivers/tty/serdev/Kconfig
new file mode 100644
index 000000000000..cdc6b820cf93
--- /dev/null
+++ b/drivers/tty/serdev/Kconfig
@@ -0,0 +1,16 @@
+#
+# Serial bus device driver configuration
+#
+menuconfig SERIAL_DEV_BUS
+	tristate "Serial device bus"
+	help
+	  Core support for devices connected via a serial port.
+
+if SERIAL_DEV_BUS
+
+config SERIAL_DEV_CTRL_TTYPORT
+	bool "Serial device TTY port controller"
+	depends on TTY
+	depends on SERIAL_DEV_BUS != m
+
+endif
diff --git a/drivers/tty/serdev/Makefile b/drivers/tty/serdev/Makefile
new file mode 100644
index 000000000000..0cbdb9444d9d
--- /dev/null
+++ b/drivers/tty/serdev/Makefile
@@ -0,0 +1,5 @@
+serdev-objs := core.o
+
+obj-$(CONFIG_SERIAL_DEV_BUS) += serdev.o
+
+obj-$(CONFIG_SERIAL_DEV_CTRL_TTYPORT) += serdev-ttyport.o
diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
new file mode 100644
index 000000000000..f4c6c90add78
--- /dev/null
+++ b/drivers/tty/serdev/core.c
@@ -0,0 +1,421 @@
+/*
+ * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
+ *
+ * Based on drivers/spmi/spmi.c:
+ * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+
+#include <linux/errno.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/serdev.h>
+#include <linux/slab.h>
+
+static bool is_registered;
+static DEFINE_IDA(ctrl_ida);
+
+static void serdev_device_release(struct device *dev)
+{
+	struct serdev_device *serdev = to_serdev_device(dev);
+	kfree(serdev);
+}
+
+static const struct device_type serdev_device_type = {
+	.release	= serdev_device_release,
+};
+
+static void serdev_ctrl_release(struct device *dev)
+{
+	struct serdev_controller *ctrl = to_serdev_controller(dev);
+	ida_simple_remove(&ctrl_ida, ctrl->nr);
+	kfree(ctrl);
+}
+
+static const struct device_type serdev_ctrl_type = {
+	.release	= serdev_ctrl_release,
+};
+
+static int serdev_device_match(struct device *dev, struct device_driver *drv)
+{
+	/* TODO: ACPI and platform matching */
+	return of_driver_match_device(dev, drv);
+}
+
+static int serdev_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	/* TODO: ACPI and platform modalias */
+	return of_device_uevent_modalias(dev, env);
+}
+
+/**
+ * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
+ * @serdev:	serdev_device to be added
+ */
+int serdev_device_add(struct serdev_device *serdev)
+{
+	struct device *parent = serdev->dev.parent;
+	int err;
+
+	dev_set_name(&serdev->dev, "%s-%d", dev_name(parent), serdev->nr);
+
+	err = device_add(&serdev->dev);
+	if (err < 0) {
+		dev_err(&serdev->dev, "Can't add %s, status %d\n",
+			dev_name(&serdev->dev), err);
+		goto err_device_add;
+	}
+
+	dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
+
+err_device_add:
+	return err;
+}
+EXPORT_SYMBOL_GPL(serdev_device_add);
+
+/**
+ * serdev_device_remove(): remove an serdev device
+ * @serdev:	serdev_device to be removed
+ */
+void serdev_device_remove(struct serdev_device *serdev)
+{
+	device_unregister(&serdev->dev);
+}
+EXPORT_SYMBOL_GPL(serdev_device_remove);
+
+int serdev_device_open(struct serdev_device *serdev)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->open)
+		return -EINVAL;
+
+	return ctrl->ops->open(ctrl);
+}
+EXPORT_SYMBOL_GPL(serdev_device_open);
+
+void serdev_device_close(struct serdev_device *serdev)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->close)
+		return;
+
+	ctrl->ops->close(ctrl);
+}
+EXPORT_SYMBOL_GPL(serdev_device_close);
+
+int serdev_device_write_buf(struct serdev_device *serdev,
+			    const unsigned char *buf, size_t count)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->write_buf)
+		return -EINVAL;
+
+	return ctrl->ops->write_buf(ctrl, buf, count);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_buf);
+
+void serdev_device_write_flush(struct serdev_device *serdev)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->write_flush)
+		return;
+
+	ctrl->ops->write_flush(ctrl);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_flush);
+
+int serdev_device_write_room(struct serdev_device *serdev)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->write_room)
+		return 0;
+
+	return serdev->ctrl->ops->write_room(ctrl);
+}
+EXPORT_SYMBOL_GPL(serdev_device_write_room);
+
+unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->set_baudrate)
+		return 0;
+
+	return ctrl->ops->set_baudrate(ctrl, speed);
+
+}
+EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
+
+void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
+{
+	struct serdev_controller *ctrl = serdev->ctrl;
+
+	if (!ctrl || !ctrl->ops->set_flow_control)
+		return;
+
+	ctrl->ops->set_flow_control(ctrl, enable);
+}
+EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
+
+static int serdev_drv_probe(struct device *dev)
+{
+	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
+
+	return sdrv->probe(to_serdev_device(dev));
+}
+
+static int serdev_drv_remove(struct device *dev)
+{
+	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
+
+	sdrv->remove(to_serdev_device(dev));
+	return 0;
+}
+
+static ssize_t modalias_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	ssize_t len = of_device_get_modalias(dev, buf, PAGE_SIZE - 2);
+	buf[len] = '\n';
+	buf[len+1] = 0;
+	return len+1;
+}
+
+static struct device_attribute serdev_device_attrs[] = {
+	__ATTR_RO(modalias),
+	__ATTR_NULL
+};
+
+static struct bus_type serdev_bus_type = {
+	.name		= "serial",
+	.match		= serdev_device_match,
+	.probe		= serdev_drv_probe,
+	.remove		= serdev_drv_remove,
+	.uevent		= serdev_uevent,
+	.dev_attrs	= serdev_device_attrs,
+};
+
+/**
+ * serdev_controller_alloc() - Allocate a new serdev device
+ * @ctrl:	associated controller
+ *
+ * Caller is responsible for either calling serdev_device_add() to add the
+ * newly allocated controller, or calling serdev_device_put() to discard it.
+ */
+struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
+{
+	struct serdev_device *serdev;
+
+	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
+	if (!serdev)
+		return NULL;
+
+	serdev->ctrl = ctrl;
+	ctrl->serdev = serdev;
+	device_initialize(&serdev->dev);
+	serdev->dev.parent = &ctrl->dev;
+	serdev->dev.bus = &serdev_bus_type;
+	serdev->dev.type = &serdev_device_type;
+	return serdev;
+}
+EXPORT_SYMBOL_GPL(serdev_device_alloc);
+
+/**
+ * serdev_controller_alloc() - Allocate a new serdev controller
+ * @parent:	parent device
+ * @size:	size of private data
+ *
+ * Caller is responsible for either calling serdev_controller_add() to add the
+ * newly allocated controller, or calling serdev_controller_put() to discard it.
+ * The allocated private data region may be accessed via
+ * serdev_controller_get_drvdata()
+ */
+struct serdev_controller *serdev_controller_alloc(struct device *parent,
+					      size_t size)
+{
+	struct serdev_controller *ctrl;
+	int id;
+
+	if (WARN_ON(!parent))
+		return NULL;
+
+	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
+	if (!ctrl)
+		return NULL;
+
+	device_initialize(&ctrl->dev);
+	ctrl->dev.type = &serdev_ctrl_type;
+	ctrl->dev.bus = &serdev_bus_type;
+	ctrl->dev.parent = parent;
+	ctrl->dev.of_node = parent->of_node;
+	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
+
+	id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
+	if (id < 0) {
+		dev_err(parent,
+			"unable to allocate serdev controller identifier.\n");
+		serdev_controller_put(ctrl);
+		return NULL;
+	}
+
+	ctrl->nr = id;
+	dev_set_name(&ctrl->dev, "serial%d", id);
+
+	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
+	return ctrl;
+}
+EXPORT_SYMBOL_GPL(serdev_controller_alloc);
+
+static int of_serdev_register_devices(struct serdev_controller *ctrl)
+{
+	struct device_node *node;
+	struct serdev_device *serdev = NULL;
+	int err;
+	bool found = false;
+
+	for_each_available_child_of_node(ctrl->dev.of_node, node) {
+		if (!of_get_property(node, "compatible", NULL))
+			continue;
+
+		dev_dbg(&ctrl->dev, "adding child %s\n", node->full_name);
+
+		serdev = serdev_device_alloc(ctrl);
+		if (!serdev)
+			continue;
+
+		serdev->dev.of_node = node;
+
+		err = serdev_device_add(serdev);
+		if (err) {
+			dev_err(&serdev->dev,
+				"failure adding device. status %d\n", err);
+			serdev_device_put(serdev);
+		} else
+			found = true;
+	}
+	if (!found)
+		return -ENODEV;
+
+	return 0;
+}
+
+/**
+ * serdev_controller_add() - Add an serdev controller
+ * @ctrl:	controller to be registered.
+ *
+ * Register a controller previously allocated via serdev_controller_alloc() with
+ * the serdev core.
+ */
+int serdev_controller_add(struct serdev_controller *ctrl)
+{
+	int ret;
+
+	/* Can't register until after driver model init */
+	if (WARN_ON(!is_registered))
+		return -EAGAIN;
+
+	ret = device_add(&ctrl->dev);
+	if (ret)
+		return ret;
+
+	ret = of_serdev_register_devices(ctrl);
+	if (ret)
+		goto out_dev_del;
+
+	dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
+		ctrl->nr, &ctrl->dev);
+	return 0;
+
+out_dev_del:
+	device_del(&ctrl->dev);
+	return ret;
+};
+EXPORT_SYMBOL_GPL(serdev_controller_add);
+
+/* Remove a device associated with a controller */
+static int serdev_remove_device(struct device *dev, void *data)
+{
+	struct serdev_device *serdev = to_serdev_device(dev);
+	if (dev->type == &serdev_device_type)
+		serdev_device_remove(serdev);
+	return 0;
+}
+
+/**
+ * serdev_controller_remove(): remove an serdev controller
+ * @ctrl:	controller to remove
+ *
+ * Remove a serdev controller.  Caller is responsible for calling
+ * serdev_controller_put() to discard the allocated controller.
+ */
+void serdev_controller_remove(struct serdev_controller *ctrl)
+{
+	int dummy;
+
+	if (!ctrl)
+		return;
+
+	dummy = device_for_each_child(&ctrl->dev, NULL,
+				      serdev_remove_device);
+	device_del(&ctrl->dev);
+}
+EXPORT_SYMBOL_GPL(serdev_controller_remove);
+
+/**
+ * serdev_driver_register() - Register client driver with serdev core
+ * @sdrv:	client driver to be associated with client-device.
+ *
+ * This API will register the client driver with the serdev framework.
+ * It is typically called from the driver's module-init function.
+ */
+int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
+{
+	sdrv->driver.bus = &serdev_bus_type;
+	sdrv->driver.owner = owner;
+
+	/* force drivers to async probe so I/O is possible in probe */
+        sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
+
+	return driver_register(&sdrv->driver);
+}
+EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
+
+static void __exit serdev_exit(void)
+{
+	bus_unregister(&serdev_bus_type);
+}
+module_exit(serdev_exit);
+
+static int __init serdev_init(void)
+{
+	int ret;
+
+	ret = bus_register(&serdev_bus_type);
+	if (ret)
+		return ret;
+
+	is_registered = true;
+	return 0;
+}
+/* Must be before serial drivers register */
+postcore_initcall(serdev_init);
+
+MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Serial attached device bus");
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
new file mode 100644
index 000000000000..d05393594f15
--- /dev/null
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * 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.
+ */
+#include <linux/kernel.h>
+#include <linux/serdev.h>
+#include <linux/tty.h>
+#include <linux/tty_driver.h>
+
+#define SERPORT_ACTIVE		1
+
+struct serport {
+	struct tty_port *port;
+	struct tty_struct *tty;
+	struct tty_driver *tty_drv;
+	int tty_idx;
+	unsigned long flags;
+};
+
+/*
+ * Callback functions from the tty port.
+ */
+
+static int ttyport_receive_buf(struct tty_port *port, const unsigned char *cp,
+				const unsigned char *fp, size_t count)
+{
+	struct serdev_controller *ctrl = port->client_data;
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+
+	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+		return 0;
+
+	return serdev_controller_receive_buf(ctrl, cp, count);
+}
+
+static void ttyport_write_wakeup(struct tty_port *port)
+{
+	struct serdev_controller *ctrl = port->client_data;
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+
+	if (!test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags))
+		return;
+
+	if (test_bit(SERPORT_ACTIVE, &serport->flags))
+		serdev_controller_write_wakeup(ctrl);
+}
+
+static const struct tty_port_client_operations client_ops = {
+	.receive_buf = ttyport_receive_buf,
+	.write_wakeup = ttyport_write_wakeup,
+};
+
+/*
+ * Callback functions from the serdev core.
+ */
+
+static int ttyport_write_buf(struct serdev_controller *ctrl, const unsigned char *data, size_t len)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+
+	if (!test_bit(SERPORT_ACTIVE, &serport->flags))
+		return 0;
+
+	set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+	return tty->ops->write(serport->tty, data, len);
+}
+
+static void ttyport_write_flush(struct serdev_controller *ctrl)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+
+	tty_driver_flush_buffer(tty);
+}
+
+static int ttyport_write_room(struct serdev_controller *ctrl)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+
+	return tty_write_room(tty);
+}
+
+static int ttyport_open(struct serdev_controller *ctrl)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty;
+	struct ktermios ktermios;
+
+	tty = tty_init_dev(serport->tty_drv, serport->tty_idx);
+	if (IS_ERR(tty))
+		return PTR_ERR(tty);
+	serport->tty = tty;
+
+	serport->port->client_ops = &client_ops;
+	serport->port->client_data = ctrl;
+
+	if (tty->ops->open)
+		tty->ops->open(serport->tty, NULL);
+	else
+		tty_port_open(serport->port, tty, NULL);
+
+	/* Bring the UART into a known 8 bits no parity hw fc state */
+	ktermios = tty->termios;
+	ktermios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP |
+			      INLCR | IGNCR | ICRNL | IXON);
+	ktermios.c_oflag &= ~OPOST;
+	ktermios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
+	ktermios.c_cflag &= ~(CSIZE | PARENB);
+	ktermios.c_cflag |= CS8;
+	ktermios.c_cflag |= CRTSCTS;
+	tty_set_termios(tty, &ktermios);
+
+	set_bit(SERPORT_ACTIVE, &serport->flags);
+
+	tty_unlock(serport->tty);
+	return 0;
+}
+
+static void ttyport_close(struct serdev_controller *ctrl)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+
+	clear_bit(SERPORT_ACTIVE, &serport->flags);
+
+	if (tty->ops->close)
+		tty->ops->close(tty, NULL);
+
+	tty_release_struct(tty, serport->tty_idx);
+}
+
+static unsigned int ttyport_set_baudrate(struct serdev_controller *ctrl, unsigned int speed)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+	struct ktermios ktermios = tty->termios;
+
+	ktermios.c_cflag &= ~CBAUD;
+	tty_termios_encode_baud_rate(&ktermios, speed, speed);
+
+	/* tty_set_termios() return not checked as it is always 0 */
+	tty_set_termios(tty, &ktermios);
+	return speed;
+}
+
+static void ttyport_set_flow_control(struct serdev_controller *ctrl, bool enable)
+{
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+	struct tty_struct *tty = serport->tty;
+	struct ktermios ktermios = tty->termios;
+
+	if (enable)
+		ktermios.c_cflag |= CRTSCTS;
+	else
+		ktermios.c_cflag &= ~CRTSCTS;
+
+	tty_set_termios(tty, &ktermios);
+}
+
+static const struct serdev_controller_ops ctrl_ops = {
+	.write_buf = ttyport_write_buf,
+	.write_flush = ttyport_write_flush,
+	.write_room = ttyport_write_room,
+	.open = ttyport_open,
+	.close = ttyport_close,
+	.set_flow_control = ttyport_set_flow_control,
+	.set_baudrate = ttyport_set_baudrate,
+};
+
+struct device *serdev_tty_port_register(struct tty_port *port,
+					struct device *parent,
+					struct tty_driver *drv, int idx)
+{
+	struct serdev_controller *ctrl;
+	struct serport *serport;
+	int ret;
+
+	if (!port || !drv || !parent)
+		return ERR_PTR(-ENODEV);
+
+	ctrl = serdev_controller_alloc(parent, sizeof(struct serport));
+	if (!ctrl)
+		return ERR_PTR(-ENOMEM);
+	serport = serdev_controller_get_drvdata(ctrl);
+
+	serport->port = port;
+	serport->tty_idx = idx;
+	serport->tty_drv = drv;
+
+	ctrl->ops = &ctrl_ops;
+
+	ret = serdev_controller_add(ctrl);
+	if (ret)
+		goto err_controller_put;
+
+	dev_info(&ctrl->dev, "tty port %s%d registered\n", drv->name, idx);
+	return &ctrl->dev;
+
+err_controller_put:
+	serdev_controller_put(ctrl);
+	return ERR_PTR(ret);
+}
+
+void serdev_tty_port_unregister(struct tty_port *port)
+{
+	struct serdev_controller *ctrl = port->client_data;
+	struct serport *serport = serdev_controller_get_drvdata(ctrl);
+
+	if (!serport)
+		return;
+
+	serdev_controller_remove(ctrl);
+	port->client_ops = NULL;
+	port->client_data = NULL;
+	serdev_controller_put(ctrl);
+}