mei: bus: Initial MEI Client bus type implementation

mei client bus will present some of the mei clients
as devices for other standard subsystems

Implement the probe, remove, match, device addtion routines, along with
the sysfs and uevent ones. mei_cl_device_id is also added to
mod_devicetable.h
A mei-cleint-bus.txt document describing the rationale and the API usage
is also added while ABI/testing/sysfs-bus-mei describeis the modalias ABI.

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 199 insertions, 0 deletions

diff --git a/drivers/misc/mei/Makefile b/drivers/misc/mei/Makefile
index 2c336d0..1b29f7c 100644
--- a/drivers/misc/mei/Makefile
+++ b/drivers/misc/mei/Makefile
@@ -10,6 +10,7 @@ mei-objs += client.o
 mei-objs += main.o
 mei-objs += amthif.o
 mei-objs += wd.o
+mei-objs += bus.o
 
 obj-$(CONFIG_INTEL_MEI_ME) += mei-me.o
 mei-me-objs := pci-me.o
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
new file mode 100644
index 0000000..78c876a
--- /dev/null
+++ b/drivers/misc/mei/bus.c
@@ -0,0 +1,172 @@
+/*
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2012-2013, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/mei_cl_bus.h>
+
+#include "mei_dev.h"
+
+#define to_mei_cl_driver(d) container_of(d, struct mei_cl_driver, driver)
+#define to_mei_cl_device(d) container_of(d, struct mei_cl_device, dev)
+
+static int mei_cl_device_match(struct device *dev, struct device_driver *drv)
+{
+	struct mei_cl_device *device = to_mei_cl_device(dev);
+	struct mei_cl_driver *driver = to_mei_cl_driver(drv);
+	const struct mei_cl_device_id *id;
+
+	if (!device)
+		return 0;
+
+	if (!driver || !driver->id_table)
+		return 0;
+
+	id = driver->id_table;
+
+	while (id->name[0]) {
+		if (!strcmp(dev_name(dev), id->name))
+			return 1;
+
+		id++;
+	}
+
+	return 0;
+}
+
+static int mei_cl_device_probe(struct device *dev)
+{
+	struct mei_cl_device *device = to_mei_cl_device(dev);
+	struct mei_cl_driver *driver;
+	struct mei_cl_device_id id;
+
+	if (!device)
+		return 0;
+
+	driver = to_mei_cl_driver(dev->driver);
+	if (!driver || !driver->probe)
+		return -ENODEV;
+
+	dev_dbg(dev, "Device probe\n");
+
+	strncpy(id.name, dev_name(dev), MEI_CL_NAME_SIZE);
+
+	return driver->probe(device, &id);
+}
+
+static int mei_cl_device_remove(struct device *dev)
+{
+	struct mei_cl_device *device = to_mei_cl_device(dev);
+	struct mei_cl_driver *driver;
+
+	if (!device || !dev->driver)
+		return 0;
+
+	driver = to_mei_cl_driver(dev->driver);
+	if (!driver->remove) {
+		dev->driver = NULL;
+
+		return 0;
+	}
+
+	return driver->remove(device);
+}
+
+static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
+			     char *buf)
+{
+	int len;
+
+	len = snprintf(buf, PAGE_SIZE, "mei:%s\n", dev_name(dev));
+
+	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
+}
+
+static struct device_attribute mei_cl_dev_attrs[] = {
+	__ATTR_RO(modalias),
+	__ATTR_NULL,
+};
+
+static int mei_cl_uevent(struct device *dev, struct kobj_uevent_env *env)
+{
+	if (add_uevent_var(env, "MODALIAS=mei:%s", dev_name(dev)))
+		return -ENOMEM;
+
+	return 0;
+}
+
+static struct bus_type mei_cl_bus_type = {
+	.name		= "mei",
+	.dev_attrs	= mei_cl_dev_attrs,
+	.match		= mei_cl_device_match,
+	.probe		= mei_cl_device_probe,
+	.remove		= mei_cl_device_remove,
+	.uevent		= mei_cl_uevent,
+};
+
+static void mei_cl_dev_release(struct device *dev)
+{
+	kfree(to_mei_cl_device(dev));
+}
+
+static struct device_type mei_cl_device_type = {
+	.release	= mei_cl_dev_release,
+};
+
+struct mei_cl_device *mei_cl_add_device(struct mei_device *mei_device,
+				  uuid_le uuid, char *name)
+{
+	struct mei_cl_device *device;
+	int status;
+
+	device = kzalloc(sizeof(struct mei_cl_device), GFP_KERNEL);
+	if (!device)
+		return NULL;
+
+	device->dev.parent = &mei_device->pdev->dev;
+	device->dev.bus = &mei_cl_bus_type;
+	device->dev.type = &mei_cl_device_type;
+
+	dev_set_name(&device->dev, "%s", name);
+
+	status = device_register(&device->dev);
+	if (status)
+		goto out_err;
+
+	dev_dbg(&device->dev, "client %s registered\n", name);
+
+	return device;
+
+out_err:
+	dev_err(device->dev.parent, "Failed to register MEI client\n");
+
+	kfree(device);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(mei_cl_add_device);
+
+void mei_cl_remove_device(struct mei_cl_device *device)
+{
+	device_unregister(&device->dev);
+}
+EXPORT_SYMBOL_GPL(mei_cl_remove_device);
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index b5d6607..7abb705d 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -21,6 +21,7 @@
 #include <linux/watchdog.h>
 #include <linux/poll.h>
 #include <linux/mei.h>
+#include <linux/mei_cl_bus.h>
 
 #include "hw.h"
 #include "hw-me-regs.h"
@@ -262,6 +263,31 @@ struct mei_hw_ops {
 		     unsigned char *buf, unsigned long len);
 };
 
+/* MEI bus API*/
+struct mei_cl_device *mei_cl_add_device(struct mei_device *dev,
+				  uuid_le uuid, char *name);
+void mei_cl_remove_device(struct mei_cl_device *device);
+
+/**
+ * struct mei_cl_device - MEI device handle
+ * An mei_cl_device pointer is returned from mei_add_device()
+ * and links MEI bus clients to their actual ME host client pointer.
+ * Drivers for MEI devices will get an mei_cl_device pointer
+ * when being probed and shall use it for doing ME bus I/O.
+ *
+ * @dev: linux driver model device pointer
+ * @uuid: me client uuid
+ * @cl: mei client
+ * @priv_data: client private data
+ */
+struct mei_cl_device {
+	struct device dev;
+
+	struct mei_cl *cl;
+
+	void *priv_data;
+};
+
 /**
  * struct mei_device -  MEI private device struct