Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1257 insertions, 0 deletions

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
new file mode 100644
index 000000000..9cdaa7f3a
--- /dev/null
+++ b/drivers/misc/mei/bus.c
@@ -0,0 +1,1257 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2012-2019, Intel Corporation. All rights reserved.
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ */
+
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/sched/signal.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/mei_cl_bus.h>
+
+#include "mei_dev.h"
+#include "client.h"
+
+#define to_mei_cl_driver(d) container_of(d, struct mei_cl_driver, driver)
+
+/**
+ * __mei_cl_send - internal client send (write)
+ *
+ * @cl: host client
+ * @buf: buffer to send
+ * @length: buffer length
+ * @mode: sending mode
+ *
+ * Return: written size bytes or < 0 on error
+ */
+ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
+		      unsigned int mode)
+{
+	struct mei_device *bus;
+	struct mei_cl_cb *cb;
+	ssize_t rets;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	bus = cl->dev;
+
+	mutex_lock(&bus->device_lock);
+	if (bus->dev_state != MEI_DEV_ENABLED) {
+		rets = -ENODEV;
+		goto out;
+	}
+
+	if (!mei_cl_is_connected(cl)) {
+		rets = -ENODEV;
+		goto out;
+	}
+
+	/* Check if we have an ME client device */
+	if (!mei_me_cl_is_active(cl->me_cl)) {
+		rets = -ENOTTY;
+		goto out;
+	}
+
+	if (length > mei_cl_mtu(cl)) {
+		rets = -EFBIG;
+		goto out;
+	}
+
+	while (cl->tx_cb_queued >= bus->tx_queue_limit) {
+		mutex_unlock(&bus->device_lock);
+		rets = wait_event_interruptible(cl->tx_wait,
+				cl->writing_state == MEI_WRITE_COMPLETE ||
+				(!mei_cl_is_connected(cl)));
+		mutex_lock(&bus->device_lock);
+		if (rets) {
+			if (signal_pending(current))
+				rets = -EINTR;
+			goto out;
+		}
+		if (!mei_cl_is_connected(cl)) {
+			rets = -ENODEV;
+			goto out;
+		}
+	}
+
+	cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, NULL);
+	if (!cb) {
+		rets = -ENOMEM;
+		goto out;
+	}
+
+	cb->internal = !!(mode & MEI_CL_IO_TX_INTERNAL);
+	cb->blocking = !!(mode & MEI_CL_IO_TX_BLOCKING);
+	memcpy(cb->buf.data, buf, length);
+
+	rets = mei_cl_write(cl, cb);
+
+out:
+	mutex_unlock(&bus->device_lock);
+
+	return rets;
+}
+
+/**
+ * __mei_cl_recv - internal client receive (read)
+ *
+ * @cl: host client
+ * @buf: buffer to receive
+ * @length: buffer length
+ * @mode: io mode
+ * @timeout: recv timeout, 0 for infinite timeout
+ *
+ * Return: read size in bytes of < 0 on error
+ */
+ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
+		      unsigned int mode, unsigned long timeout)
+{
+	struct mei_device *bus;
+	struct mei_cl_cb *cb;
+	size_t r_length;
+	ssize_t rets;
+	bool nonblock = !!(mode & MEI_CL_IO_RX_NONBLOCK);
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	bus = cl->dev;
+
+	mutex_lock(&bus->device_lock);
+	if (bus->dev_state != MEI_DEV_ENABLED) {
+		rets = -ENODEV;
+		goto out;
+	}
+
+	cb = mei_cl_read_cb(cl, NULL);
+	if (cb)
+		goto copy;
+
+	rets = mei_cl_read_start(cl, length, NULL);
+	if (rets && rets != -EBUSY)
+		goto out;
+
+	if (nonblock) {
+		rets = -EAGAIN;
+		goto out;
+	}
+
+	/* wait on event only if there is no other waiter */
+	/* synchronized under device mutex */
+	if (!waitqueue_active(&cl->rx_wait)) {
+
+		mutex_unlock(&bus->device_lock);
+
+		if (timeout) {
+			rets = wait_event_interruptible_timeout
+					(cl->rx_wait,
+					mei_cl_read_cb(cl, NULL) ||
+					(!mei_cl_is_connected(cl)),
+					msecs_to_jiffies(timeout));
+			if (rets == 0)
+				return -ETIME;
+			if (rets < 0) {
+				if (signal_pending(current))
+					return -EINTR;
+				return -ERESTARTSYS;
+			}
+		} else {
+			if (wait_event_interruptible
+					(cl->rx_wait,
+					mei_cl_read_cb(cl, NULL) ||
+					(!mei_cl_is_connected(cl)))) {
+				if (signal_pending(current))
+					return -EINTR;
+				return -ERESTARTSYS;
+			}
+		}
+
+		mutex_lock(&bus->device_lock);
+
+		if (!mei_cl_is_connected(cl)) {
+			rets = -ENODEV;
+			goto out;
+		}
+	}
+
+	cb = mei_cl_read_cb(cl, NULL);
+	if (!cb) {
+		rets = 0;
+		goto out;
+	}
+
+copy:
+	if (cb->status) {
+		rets = cb->status;
+		goto free;
+	}
+
+	r_length = min_t(size_t, length, cb->buf_idx);
+	memcpy(buf, cb->buf.data, r_length);
+	rets = r_length;
+
+free:
+	mei_cl_del_rd_completed(cl, cb);
+out:
+	mutex_unlock(&bus->device_lock);
+
+	return rets;
+}
+
+/**
+ * mei_cldev_send - me device send  (write)
+ *
+ * @cldev: me client device
+ * @buf: buffer to send
+ * @length: buffer length
+ *
+ * Return: written size in bytes or < 0 on error
+ */
+ssize_t mei_cldev_send(struct mei_cl_device *cldev, u8 *buf, size_t length)
+{
+	struct mei_cl *cl = cldev->cl;
+
+	return __mei_cl_send(cl, buf, length, MEI_CL_IO_TX_BLOCKING);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_send);
+
+/**
+ * mei_cldev_recv_nonblock - non block client receive (read)
+ *
+ * @cldev: me client device
+ * @buf: buffer to receive
+ * @length: buffer length
+ *
+ * Return: read size in bytes of < 0 on error
+ *         -EAGAIN if function will block.
+ */
+ssize_t mei_cldev_recv_nonblock(struct mei_cl_device *cldev, u8 *buf,
+				size_t length)
+{
+	struct mei_cl *cl = cldev->cl;
+
+	return __mei_cl_recv(cl, buf, length, MEI_CL_IO_RX_NONBLOCK, 0);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_recv_nonblock);
+
+/**
+ * mei_cldev_recv - client receive (read)
+ *
+ * @cldev: me client device
+ * @buf: buffer to receive
+ * @length: buffer length
+ *
+ * Return: read size in bytes of < 0 on error
+ */
+ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length)
+{
+	struct mei_cl *cl = cldev->cl;
+
+	return __mei_cl_recv(cl, buf, length, 0, 0);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_recv);
+
+/**
+ * mei_cl_bus_rx_work - dispatch rx event for a bus device
+ *
+ * @work: work
+ */
+static void mei_cl_bus_rx_work(struct work_struct *work)
+{
+	struct mei_cl_device *cldev;
+	struct mei_device *bus;
+
+	cldev = container_of(work, struct mei_cl_device, rx_work);
+
+	bus = cldev->bus;
+
+	if (cldev->rx_cb)
+		cldev->rx_cb(cldev);
+
+	mutex_lock(&bus->device_lock);
+	mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
+	mutex_unlock(&bus->device_lock);
+}
+
+/**
+ * mei_cl_bus_notif_work - dispatch FW notif event for a bus device
+ *
+ * @work: work
+ */
+static void mei_cl_bus_notif_work(struct work_struct *work)
+{
+	struct mei_cl_device *cldev;
+
+	cldev = container_of(work, struct mei_cl_device, notif_work);
+
+	if (cldev->notif_cb)
+		cldev->notif_cb(cldev);
+}
+
+/**
+ * mei_cl_bus_notify_event - schedule notify cb on bus client
+ *
+ * @cl: host client
+ *
+ * Return: true if event was scheduled
+ *         false if the client is not waiting for event
+ */
+bool mei_cl_bus_notify_event(struct mei_cl *cl)
+{
+	struct mei_cl_device *cldev = cl->cldev;
+
+	if (!cldev || !cldev->notif_cb)
+		return false;
+
+	if (!cl->notify_ev)
+		return false;
+
+	schedule_work(&cldev->notif_work);
+
+	cl->notify_ev = false;
+
+	return true;
+}
+
+/**
+ * mei_cl_bus_rx_event - schedule rx event
+ *
+ * @cl: host client
+ *
+ * Return: true if event was scheduled
+ *         false if the client is not waiting for event
+ */
+bool mei_cl_bus_rx_event(struct mei_cl *cl)
+{
+	struct mei_cl_device *cldev = cl->cldev;
+
+	if (!cldev || !cldev->rx_cb)
+		return false;
+
+	schedule_work(&cldev->rx_work);
+
+	return true;
+}
+
+/**
+ * mei_cldev_register_rx_cb - register Rx event callback
+ *
+ * @cldev: me client devices
+ * @rx_cb: callback function
+ *
+ * Return: 0 on success
+ *         -EALREADY if an callback is already registered
+ *         <0 on other errors
+ */
+int mei_cldev_register_rx_cb(struct mei_cl_device *cldev, mei_cldev_cb_t rx_cb)
+{
+	struct mei_device *bus = cldev->bus;
+	int ret;
+
+	if (!rx_cb)
+		return -EINVAL;
+	if (cldev->rx_cb)
+		return -EALREADY;
+
+	cldev->rx_cb = rx_cb;
+	INIT_WORK(&cldev->rx_work, mei_cl_bus_rx_work);
+
+	mutex_lock(&bus->device_lock);
+	ret = mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
+	mutex_unlock(&bus->device_lock);
+	if (ret && ret != -EBUSY)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_register_rx_cb);
+
+/**
+ * mei_cldev_register_notif_cb - register FW notification event callback
+ *
+ * @cldev: me client devices
+ * @notif_cb: callback function
+ *
+ * Return: 0 on success
+ *         -EALREADY if an callback is already registered
+ *         <0 on other errors
+ */
+int mei_cldev_register_notif_cb(struct mei_cl_device *cldev,
+				mei_cldev_cb_t notif_cb)
+{
+	struct mei_device *bus = cldev->bus;
+	int ret;
+
+	if (!notif_cb)
+		return -EINVAL;
+
+	if (cldev->notif_cb)
+		return -EALREADY;
+
+	cldev->notif_cb = notif_cb;
+	INIT_WORK(&cldev->notif_work, mei_cl_bus_notif_work);
+
+	mutex_lock(&bus->device_lock);
+	ret = mei_cl_notify_request(cldev->cl, NULL, 1);
+	mutex_unlock(&bus->device_lock);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_register_notif_cb);
+
+/**
+ * mei_cldev_get_drvdata - driver data getter
+ *
+ * @cldev: mei client device
+ *
+ * Return: driver private data
+ */
+void *mei_cldev_get_drvdata(const struct mei_cl_device *cldev)
+{
+	return dev_get_drvdata(&cldev->dev);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_get_drvdata);
+
+/**
+ * mei_cldev_set_drvdata - driver data setter
+ *
+ * @cldev: mei client device
+ * @data: data to store
+ */
+void mei_cldev_set_drvdata(struct mei_cl_device *cldev, void *data)
+{
+	dev_set_drvdata(&cldev->dev, data);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_set_drvdata);
+
+/**
+ * mei_cldev_uuid - return uuid of the underlying me client
+ *
+ * @cldev: mei client device
+ *
+ * Return: me client uuid
+ */
+const uuid_le *mei_cldev_uuid(const struct mei_cl_device *cldev)
+{
+	return mei_me_cl_uuid(cldev->me_cl);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_uuid);
+
+/**
+ * mei_cldev_ver - return protocol version of the underlying me client
+ *
+ * @cldev: mei client device
+ *
+ * Return: me client protocol version
+ */
+u8 mei_cldev_ver(const struct mei_cl_device *cldev)
+{
+	return mei_me_cl_ver(cldev->me_cl);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_ver);
+
+/**
+ * mei_cldev_enabled - check whether the device is enabled
+ *
+ * @cldev: mei client device
+ *
+ * Return: true if me client is initialized and connected
+ */
+bool mei_cldev_enabled(struct mei_cl_device *cldev)
+{
+	return mei_cl_is_connected(cldev->cl);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_enabled);
+
+/**
+ * mei_cl_bus_module_get - acquire module of the underlying
+ *    hw driver.
+ *
+ * @cldev: mei client device
+ *
+ * Return: true on success; false if the module was removed.
+ */
+static bool mei_cl_bus_module_get(struct mei_cl_device *cldev)
+{
+	return try_module_get(cldev->bus->dev->driver->owner);
+}
+
+/**
+ * mei_cl_bus_module_put -  release the underlying hw module.
+ *
+ * @cldev: mei client device
+ */
+static void mei_cl_bus_module_put(struct mei_cl_device *cldev)
+{
+	module_put(cldev->bus->dev->driver->owner);
+}
+
+/**
+ * mei_cl_bus_vtag - get bus vtag entry wrapper
+ *     The tag for bus client is always first.
+ *
+ * @cl: host client
+ *
+ * Return: bus vtag or NULL
+ */
+static inline struct mei_cl_vtag *mei_cl_bus_vtag(struct mei_cl *cl)
+{
+	return list_first_entry_or_null(&cl->vtag_map,
+					struct mei_cl_vtag, list);
+}
+
+/**
+ * mei_cl_bus_vtag_alloc - add bus client entry to vtag map
+ *
+ * @cldev: me client device
+ *
+ * Return:
+ * * 0 on success
+ * * -ENOMEM if memory allocation failed
+ */
+static int mei_cl_bus_vtag_alloc(struct mei_cl_device *cldev)
+{
+	struct mei_cl *cl = cldev->cl;
+	struct mei_cl_vtag *cl_vtag;
+
+	/*
+	 * Bail out if the client does not supports vtags
+	 * or has already allocated one
+	 */
+	if (mei_cl_vt_support_check(cl) || mei_cl_bus_vtag(cl))
+		return 0;
+
+	cl_vtag = mei_cl_vtag_alloc(NULL, 0);
+	if (IS_ERR(cl_vtag))
+		return -ENOMEM;
+
+	list_add_tail(&cl_vtag->list, &cl->vtag_map);
+
+	return 0;
+}
+
+/**
+ * mei_cl_bus_vtag_free - remove the bus entry from vtag map
+ *
+ * @cldev: me client device
+ */
+static void mei_cl_bus_vtag_free(struct mei_cl_device *cldev)
+{
+	struct mei_cl *cl = cldev->cl;
+	struct mei_cl_vtag *cl_vtag;
+
+	cl_vtag = mei_cl_bus_vtag(cl);
+	if (!cl_vtag)
+		return;
+
+	list_del(&cl_vtag->list);
+	kfree(cl_vtag);
+}
+
+/**
+ * mei_cldev_enable - enable me client device
+ *     create connection with me client
+ *
+ * @cldev: me client device
+ *
+ * Return: 0 on success and < 0 on error
+ */
+int mei_cldev_enable(struct mei_cl_device *cldev)
+{
+	struct mei_device *bus = cldev->bus;
+	struct mei_cl *cl;
+	int ret;
+
+	cl = cldev->cl;
+
+	mutex_lock(&bus->device_lock);
+	if (cl->state == MEI_FILE_UNINITIALIZED) {
+		ret = mei_cl_link(cl);
+		if (ret)
+			goto out;
+		/* update pointers */
+		cl->cldev = cldev;
+	}
+
+	if (mei_cl_is_connected(cl)) {
+		ret = 0;
+		goto out;
+	}
+
+	if (!mei_me_cl_is_active(cldev->me_cl)) {
+		dev_err(&cldev->dev, "me client is not active\n");
+		ret = -ENOTTY;
+		goto out;
+	}
+
+	ret = mei_cl_bus_vtag_alloc(cldev);
+	if (ret)
+		goto out;
+
+	ret = mei_cl_connect(cl, cldev->me_cl, NULL);
+	if (ret < 0) {
+		dev_err(&cldev->dev, "cannot connect\n");
+		mei_cl_bus_vtag_free(cldev);
+	}
+
+out:
+	mutex_unlock(&bus->device_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_enable);
+
+/**
+ * mei_cldev_unregister_callbacks - internal wrapper for unregistering
+ *  callbacks.
+ *
+ * @cldev: client device
+ */
+static void mei_cldev_unregister_callbacks(struct mei_cl_device *cldev)
+{
+	if (cldev->rx_cb) {
+		cancel_work_sync(&cldev->rx_work);
+		cldev->rx_cb = NULL;
+	}
+
+	if (cldev->notif_cb) {
+		cancel_work_sync(&cldev->notif_work);
+		cldev->notif_cb = NULL;
+	}
+}
+
+/**
+ * mei_cldev_disable - disable me client device
+ *     disconnect form the me client
+ *
+ * @cldev: me client device
+ *
+ * Return: 0 on success and < 0 on error
+ */
+int mei_cldev_disable(struct mei_cl_device *cldev)
+{
+	struct mei_device *bus;
+	struct mei_cl *cl;
+	int err;
+
+	if (!cldev)
+		return -ENODEV;
+
+	cl = cldev->cl;
+
+	bus = cldev->bus;
+
+	mei_cldev_unregister_callbacks(cldev);
+
+	mutex_lock(&bus->device_lock);
+
+	mei_cl_bus_vtag_free(cldev);
+
+	if (!mei_cl_is_connected(cl)) {
+		dev_dbg(bus->dev, "Already disconnected\n");
+		err = 0;
+		goto out;
+	}
+
+	err = mei_cl_disconnect(cl);
+	if (err < 0)
+		dev_err(bus->dev, "Could not disconnect from the ME client\n");
+
+out:
+	/* Flush queues and remove any pending read */
+	mei_cl_flush_queues(cl, NULL);
+	mei_cl_unlink(cl);
+
+	mutex_unlock(&bus->device_lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_disable);
+
+/**
+ * mei_cl_device_find - find matching entry in the driver id table
+ *
+ * @cldev: me client device
+ * @cldrv: me client driver
+ *
+ * Return: id on success; NULL if no id is matching
+ */
+static const
+struct mei_cl_device_id *mei_cl_device_find(struct mei_cl_device *cldev,
+					    struct mei_cl_driver *cldrv)
+{
+	const struct mei_cl_device_id *id;
+	const uuid_le *uuid;
+	u8 version;
+	bool match;
+
+	uuid = mei_me_cl_uuid(cldev->me_cl);
+	version = mei_me_cl_ver(cldev->me_cl);
+
+	id = cldrv->id_table;
+	while (uuid_le_cmp(NULL_UUID_LE, id->uuid)) {
+		if (!uuid_le_cmp(*uuid, id->uuid)) {
+			match = true;
+
+			if (cldev->name[0])
+				if (strncmp(cldev->name, id->name,
+					    sizeof(id->name)))
+					match = false;
+
+			if (id->version != MEI_CL_VERSION_ANY)
+				if (id->version != version)
+					match = false;
+			if (match)
+				return id;
+		}
+
+		id++;
+	}
+
+	return NULL;
+}
+
+/**
+ * mei_cl_device_match  - device match function
+ *
+ * @dev: device
+ * @drv: driver
+ *
+ * Return:  1 if matching device was found 0 otherwise
+ */
+static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	struct mei_cl_driver *cldrv = to_mei_cl_driver(drv);
+	const struct mei_cl_device_id *found_id;
+
+	if (!cldev)
+		return 0;
+
+	if (!cldev->do_match)
+		return 0;
+
+	if (!cldrv || !cldrv->id_table)
+		return 0;
+
+	found_id = mei_cl_device_find(cldev, cldrv);
+	if (found_id)
+		return 1;
+
+	return 0;
+}
+
+/**
+ * mei_cl_device_probe - bus probe function
+ *
+ * @dev: device
+ *
+ * Return:  0 on success; < 0 otherwise
+ */
+static int mei_cl_device_probe(struct device *dev)
+{
+	struct mei_cl_device *cldev;
+	struct mei_cl_driver *cldrv;
+	const struct mei_cl_device_id *id;
+	int ret;
+
+	cldev = to_mei_cl_device(dev);
+	cldrv = to_mei_cl_driver(dev->driver);
+
+	if (!cldev)
+		return 0;
+
+	if (!cldrv || !cldrv->probe)
+		return -ENODEV;
+
+	id = mei_cl_device_find(cldev, cldrv);
+	if (!id)
+		return -ENODEV;
+
+	if (!mei_cl_bus_module_get(cldev)) {
+		dev_err(&cldev->dev, "get hw module failed");
+		return -ENODEV;
+	}
+
+	ret = cldrv->probe(cldev, id);
+	if (ret) {
+		mei_cl_bus_module_put(cldev);
+		return ret;
+	}
+
+	__module_get(THIS_MODULE);
+	return 0;
+}
+
+/**
+ * mei_cl_device_remove - remove device from the bus
+ *
+ * @dev: device
+ *
+ * Return:  0 on success; < 0 otherwise
+ */
+static int mei_cl_device_remove(struct device *dev)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	struct mei_cl_driver *cldrv;
+	int ret = 0;
+
+	if (!cldev || !dev->driver)
+		return 0;
+
+	cldrv = to_mei_cl_driver(dev->driver);
+	if (cldrv->remove)
+		ret = cldrv->remove(cldev);
+
+	mei_cldev_unregister_callbacks(cldev);
+
+	mei_cl_bus_module_put(cldev);
+	module_put(THIS_MODULE);
+
+	return ret;
+}
+
+static ssize_t name_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%s", cldev->name);
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t uuid_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
+
+	return sprintf(buf, "%pUl", uuid);
+}
+static DEVICE_ATTR_RO(uuid);
+
+static ssize_t version_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	u8 version = mei_me_cl_ver(cldev->me_cl);
+
+	return sprintf(buf, "%02X", version);
+}
+static DEVICE_ATTR_RO(version);
+
+static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
+	u8 version = mei_me_cl_ver(cldev->me_cl);
+
+	return scnprintf(buf, PAGE_SIZE, "mei:%s:%pUl:%02X:",
+			 cldev->name, uuid, version);
+}
+static DEVICE_ATTR_RO(modalias);
+
+static ssize_t max_conn_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	u8 maxconn = mei_me_cl_max_conn(cldev->me_cl);
+
+	return sprintf(buf, "%d", maxconn);
+}
+static DEVICE_ATTR_RO(max_conn);
+
+static ssize_t fixed_show(struct device *dev, struct device_attribute *a,
+			  char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	u8 fixed = mei_me_cl_fixed(cldev->me_cl);
+
+	return sprintf(buf, "%d", fixed);
+}
+static DEVICE_ATTR_RO(fixed);
+
+static ssize_t vtag_show(struct device *dev, struct device_attribute *a,
+			 char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	bool vt = mei_me_cl_vt(cldev->me_cl);
+
+	return sprintf(buf, "%d", vt);
+}
+static DEVICE_ATTR_RO(vtag);
+
+static ssize_t max_len_show(struct device *dev, struct device_attribute *a,
+			    char *buf)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	u32 maxlen = mei_me_cl_max_len(cldev->me_cl);
+
+	return sprintf(buf, "%u", maxlen);
+}
+static DEVICE_ATTR_RO(max_len);
+
+static struct attribute *mei_cldev_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_uuid.attr,
+	&dev_attr_version.attr,
+	&dev_attr_modalias.attr,
+	&dev_attr_max_conn.attr,
+	&dev_attr_fixed.attr,
+	&dev_attr_vtag.attr,
+	&dev_attr_max_len.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(mei_cldev);
+
+/**
+ * mei_cl_device_uevent - me client bus uevent handler
+ *
+ * @dev: device
+ * @env: uevent kobject
+ *
+ * Return: 0 on success -ENOMEM on when add_uevent_var fails
+ */
+static int mei_cl_device_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+	const uuid_le *uuid = mei_me_cl_uuid(cldev->me_cl);
+	u8 version = mei_me_cl_ver(cldev->me_cl);
+
+	if (add_uevent_var(env, "MEI_CL_VERSION=%d", version))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MEI_CL_UUID=%pUl", uuid))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MEI_CL_NAME=%s", cldev->name))
+		return -ENOMEM;
+
+	if (add_uevent_var(env, "MODALIAS=mei:%s:%pUl:%02X:",
+			   cldev->name, uuid, version))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static struct bus_type mei_cl_bus_type = {
+	.name		= "mei",
+	.dev_groups	= mei_cldev_groups,
+	.match		= mei_cl_device_match,
+	.probe		= mei_cl_device_probe,
+	.remove		= mei_cl_device_remove,
+	.uevent		= mei_cl_device_uevent,
+};
+
+static struct mei_device *mei_dev_bus_get(struct mei_device *bus)
+{
+	if (bus)
+		get_device(bus->dev);
+
+	return bus;
+}
+
+static void mei_dev_bus_put(struct mei_device *bus)
+{
+	if (bus)
+		put_device(bus->dev);
+}
+
+static void mei_cl_bus_dev_release(struct device *dev)
+{
+	struct mei_cl_device *cldev = to_mei_cl_device(dev);
+
+	if (!cldev)
+		return;
+
+	mei_me_cl_put(cldev->me_cl);
+	mei_dev_bus_put(cldev->bus);
+	mei_cl_unlink(cldev->cl);
+	kfree(cldev->cl);
+	kfree(cldev);
+}
+
+static const struct device_type mei_cl_device_type = {
+	.release = mei_cl_bus_dev_release,
+};
+
+/**
+ * mei_cl_bus_set_name - set device name for me client device
+ *  <controller>-<client device>
+ *  Example: 0000:00:16.0-55213584-9a29-4916-badf-0fb7ed682aeb
+ *
+ * @cldev: me client device
+ */
+static inline void mei_cl_bus_set_name(struct mei_cl_device *cldev)
+{
+	dev_set_name(&cldev->dev, "%s-%pUl",
+		     dev_name(cldev->bus->dev),
+		     mei_me_cl_uuid(cldev->me_cl));
+}
+
+/**
+ * mei_cl_bus_dev_alloc - initialize and allocate mei client device
+ *
+ * @bus: mei device
+ * @me_cl: me client
+ *
+ * Return: allocated device structur or NULL on allocation failure
+ */
+static struct mei_cl_device *mei_cl_bus_dev_alloc(struct mei_device *bus,
+						  struct mei_me_client *me_cl)
+{
+	struct mei_cl_device *cldev;
+	struct mei_cl *cl;
+
+	cldev = kzalloc(sizeof(*cldev), GFP_KERNEL);
+	if (!cldev)
+		return NULL;
+
+	cl = mei_cl_allocate(bus);
+	if (!cl) {
+		kfree(cldev);
+		return NULL;
+	}
+
+	device_initialize(&cldev->dev);
+	cldev->dev.parent = bus->dev;
+	cldev->dev.bus    = &mei_cl_bus_type;
+	cldev->dev.type   = &mei_cl_device_type;
+	cldev->bus        = mei_dev_bus_get(bus);
+	cldev->me_cl      = mei_me_cl_get(me_cl);
+	cldev->cl         = cl;
+	mei_cl_bus_set_name(cldev);
+	cldev->is_added   = 0;
+	INIT_LIST_HEAD(&cldev->bus_list);
+
+	return cldev;
+}
+
+/**
+ * mei_cl_dev_setup - setup me client device
+ *    run fix up routines and set the device name
+ *
+ * @bus: mei device
+ * @cldev: me client device
+ *
+ * Return: true if the device is eligible for enumeration
+ */
+static bool mei_cl_bus_dev_setup(struct mei_device *bus,
+				 struct mei_cl_device *cldev)
+{
+	cldev->do_match = 1;
+	mei_cl_bus_dev_fixup(cldev);
+
+	/* the device name can change during fix up */
+	if (cldev->do_match)
+		mei_cl_bus_set_name(cldev);
+
+	return cldev->do_match == 1;
+}
+
+/**
+ * mei_cl_bus_dev_add - add me client devices
+ *
+ * @cldev: me client device
+ *
+ * Return: 0 on success; < 0 on failre
+ */
+static int mei_cl_bus_dev_add(struct mei_cl_device *cldev)
+{
+	int ret;
+
+	dev_dbg(cldev->bus->dev, "adding %pUL:%02X\n",
+		mei_me_cl_uuid(cldev->me_cl),
+		mei_me_cl_ver(cldev->me_cl));
+	ret = device_add(&cldev->dev);
+	if (!ret)
+		cldev->is_added = 1;
+
+	return ret;
+}
+
+/**
+ * mei_cl_bus_dev_stop - stop the driver
+ *
+ * @cldev: me client device
+ */
+static void mei_cl_bus_dev_stop(struct mei_cl_device *cldev)
+{
+	if (cldev->is_added)
+		device_release_driver(&cldev->dev);
+}
+
+/**
+ * mei_cl_bus_dev_destroy - destroy me client devices object
+ *
+ * @cldev: me client device
+ *
+ * Locking: called under "dev->cl_bus_lock" lock
+ */
+static void mei_cl_bus_dev_destroy(struct mei_cl_device *cldev)
+{
+
+	WARN_ON(!mutex_is_locked(&cldev->bus->cl_bus_lock));
+
+	if (!cldev->is_added)
+		return;
+
+	device_del(&cldev->dev);
+
+	list_del_init(&cldev->bus_list);
+
+	cldev->is_added = 0;
+	put_device(&cldev->dev);
+}
+
+/**
+ * mei_cl_bus_remove_device - remove a devices form the bus
+ *
+ * @cldev: me client device
+ */
+static void mei_cl_bus_remove_device(struct mei_cl_device *cldev)
+{
+	mei_cl_bus_dev_stop(cldev);
+	mei_cl_bus_dev_destroy(cldev);
+}
+
+/**
+ * mei_cl_bus_remove_devices - remove all devices form the bus
+ *
+ * @bus: mei device
+ */
+void mei_cl_bus_remove_devices(struct mei_device *bus)
+{
+	struct mei_cl_device *cldev, *next;
+
+	mutex_lock(&bus->cl_bus_lock);
+	list_for_each_entry_safe(cldev, next, &bus->device_list, bus_list)
+		mei_cl_bus_remove_device(cldev);
+	mutex_unlock(&bus->cl_bus_lock);
+}
+
+
+/**
+ * mei_cl_bus_dev_init - allocate and initializes an mei client devices
+ *     based on me client
+ *
+ * @bus: mei device
+ * @me_cl: me client
+ *
+ * Locking: called under "dev->cl_bus_lock" lock
+ */
+static void mei_cl_bus_dev_init(struct mei_device *bus,
+				struct mei_me_client *me_cl)
+{
+	struct mei_cl_device *cldev;
+
+	WARN_ON(!mutex_is_locked(&bus->cl_bus_lock));
+
+	dev_dbg(bus->dev, "initializing %pUl", mei_me_cl_uuid(me_cl));
+
+	if (me_cl->bus_added)
+		return;
+
+	cldev = mei_cl_bus_dev_alloc(bus, me_cl);
+	if (!cldev)
+		return;
+
+	me_cl->bus_added = true;
+	list_add_tail(&cldev->bus_list, &bus->device_list);
+
+}
+
+/**
+ * mei_cl_bus_rescan - scan me clients list and add create
+ *    devices for eligible clients
+ *
+ * @bus: mei device
+ */
+static void mei_cl_bus_rescan(struct mei_device *bus)
+{
+	struct mei_cl_device *cldev, *n;
+	struct mei_me_client *me_cl;
+
+	mutex_lock(&bus->cl_bus_lock);
+
+	down_read(&bus->me_clients_rwsem);
+	list_for_each_entry(me_cl, &bus->me_clients, list)
+		mei_cl_bus_dev_init(bus, me_cl);
+	up_read(&bus->me_clients_rwsem);
+
+	list_for_each_entry_safe(cldev, n, &bus->device_list, bus_list) {
+
+		if (!mei_me_cl_is_active(cldev->me_cl)) {
+			mei_cl_bus_remove_device(cldev);
+			continue;
+		}
+
+		if (cldev->is_added)
+			continue;
+
+		if (mei_cl_bus_dev_setup(bus, cldev))
+			mei_cl_bus_dev_add(cldev);
+		else {
+			list_del_init(&cldev->bus_list);
+			put_device(&cldev->dev);
+		}
+	}
+	mutex_unlock(&bus->cl_bus_lock);
+
+	dev_dbg(bus->dev, "rescan end");
+}
+
+void mei_cl_bus_rescan_work(struct work_struct *work)
+{
+	struct mei_device *bus =
+		container_of(work, struct mei_device, bus_rescan_work);
+
+	mei_cl_bus_rescan(bus);
+}
+
+int __mei_cldev_driver_register(struct mei_cl_driver *cldrv,
+				struct module *owner)
+{
+	int err;
+
+	cldrv->driver.name = cldrv->name;
+	cldrv->driver.owner = owner;
+	cldrv->driver.bus = &mei_cl_bus_type;
+
+	err = driver_register(&cldrv->driver);
+	if (err)
+		return err;
+
+	pr_debug("mei: driver [%s] registered\n", cldrv->driver.name);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__mei_cldev_driver_register);
+
+void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv)
+{
+	driver_unregister(&cldrv->driver);
+
+	pr_debug("mei: driver [%s] unregistered\n", cldrv->driver.name);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_driver_unregister);
+
+
+int __init mei_cl_bus_init(void)
+{
+	return bus_register(&mei_cl_bus_type);
+}
+
+void __exit mei_cl_bus_exit(void)
+{
+	bus_unregister(&mei_cl_bus_type);
+}