1 files changed, 421 insertions, 0 deletions

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");