libnvdimm, nfit: dimm/memory-devices

Enable nvdimm devices to be registered on a nvdimm_bus.  The kernel
assigned device id for nvdimm devicesis dynamic.  If userspace needs a
more static identifier it should consult a provider-specific attribute.
In the case where NFIT is the provider, the 'nmemX/nfit/handle' or
'nmemX/nfit/serial' attributes may be used for this purpose.

Cc: Neil Brown <neilb@suse.de>
Cc: <linux-acpi@vger.kernel.org>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Toshi Kani <toshi.kani@hp.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/nvdimm/Makefile

@@ -2,3 +2,4 @@ obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o
 
 libnvdimm-y := core.o
 libnvdimm-y += bus.o
+libnvdimm-y += dimm_devs.o

drivers/nvdimm/bus.c

@@ -13,6 +13,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/uaccess.h>
 #include <linux/fcntl.h>
+#include <linux/async.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/io.h>
@@ -21,6 +22,10 @@
 static int nvdimm_bus_major;
 static struct class *nd_class;
 
+struct bus_type nvdimm_bus_type = {
+	.name = "nd",
+};
+
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus)
 {
 	dev_t devt = MKDEV(nvdimm_bus_major, nvdimm_bus->id);
@@ -59,9 +64,13 @@ int __init nvdimm_bus_init(void)
 {
 	int rc;
 
+	rc = bus_register(&nvdimm_bus_type);
+	if (rc)
+		return rc;
+
 	rc = register_chrdev(0, "ndctl", &nvdimm_bus_fops);
 	if (rc < 0)
-		return rc;
+		goto err_chrdev;
 	nvdimm_bus_major = rc;
 
 	nd_class = class_create(THIS_MODULE, "nd");
@@ -72,6 +81,8 @@ int __init nvdimm_bus_init(void)
 
  err_class:
 	unregister_chrdev(nvdimm_bus_major, "ndctl");
+ err_chrdev:
+	bus_unregister(&nvdimm_bus_type);
 
 	return rc;
 }
@@ -80,4 +91,5 @@ void __exit nvdimm_bus_exit(void)
 {
 	class_destroy(nd_class);
 	unregister_chrdev(nvdimm_bus_major, "ndctl");
+	bus_unregister(&nvdimm_bus_type);
 }

drivers/nvdimm/core.c

@@ -18,8 +18,8 @@
 #include <linux/slab.h>
 #include "nd-core.h"
 
-static LIST_HEAD(nvdimm_bus_list);
-static DEFINE_MUTEX(nvdimm_bus_list_mutex);
+LIST_HEAD(nvdimm_bus_list);
+DEFINE_MUTEX(nvdimm_bus_list_mutex);
 static DEFINE_IDA(nd_ida);
 
 static void nvdimm_bus_release(struct device *dev)
@@ -48,6 +48,19 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
 }
 EXPORT_SYMBOL_GPL(to_nd_desc);
 
+struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
+{
+	struct device *dev;
+
+	for (dev = nd_dev; dev; dev = dev->parent)
+		if (dev->release == nvdimm_bus_release)
+			break;
+	dev_WARN_ONCE(nd_dev, !dev, "invalid dev, not on nd bus\n");
+	if (dev)
+		return to_nvdimm_bus(dev);
+	return NULL;
+}
+
 static const char *nvdimm_bus_provider(struct nvdimm_bus *nvdimm_bus)
 {
 	struct nvdimm_bus_descriptor *nd_desc = nvdimm_bus->nd_desc;
@@ -121,6 +134,21 @@ struct nvdimm_bus *nvdimm_bus_register(struct device *parent,
 }
 EXPORT_SYMBOL_GPL(nvdimm_bus_register);
 
+static int child_unregister(struct device *dev, void *data)
+{
+	/*
+	 * the singular ndctl class device per bus needs to be
+	 * "device_destroy"ed, so skip it here
+	 *
+	 * i.e. remove classless children
+	 */
+	if (dev->class)
+		/* pass */;
+	else
+		device_unregister(dev);
+	return 0;
+}
+
 void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
 {
 	if (!nvdimm_bus)
@@ -130,6 +158,7 @@ void nvdimm_bus_unregister(struct nvdimm_bus *nvdimm_bus)
 	list_del_init(&nvdimm_bus->list);
 	mutex_unlock(&nvdimm_bus_list_mutex);
 
+	device_for_each_child(&nvdimm_bus->dev, NULL, child_unregister);
 	nvdimm_bus_destroy_ndctl(nvdimm_bus);
 
 	device_unregister(&nvdimm_bus->dev);

drivers/nvdimm/dimm_devs.c

@@ -0,0 +1,92 @@
+/*
+ * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License 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.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include "nd-core.h"
+
+static DEFINE_IDA(dimm_ida);
+
+static void nvdimm_release(struct device *dev)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+
+	ida_simple_remove(&dimm_ida, nvdimm->id);
+	kfree(nvdimm);
+}
+
+static struct device_type nvdimm_device_type = {
+	.name = "nvdimm",
+	.release = nvdimm_release,
+};
+
+static bool is_nvdimm(struct device *dev)
+{
+	return dev->type == &nvdimm_device_type;
+}
+
+struct nvdimm *to_nvdimm(struct device *dev)
+{
+	struct nvdimm *nvdimm = container_of(dev, struct nvdimm, dev);
+
+	WARN_ON(!is_nvdimm(dev));
+	return nvdimm;
+}
+EXPORT_SYMBOL_GPL(to_nvdimm);
+
+const char *nvdimm_name(struct nvdimm *nvdimm)
+{
+	return dev_name(&nvdimm->dev);
+}
+EXPORT_SYMBOL_GPL(nvdimm_name);
+
+void *nvdimm_provider_data(struct nvdimm *nvdimm)
+{
+	return nvdimm->provider_data;
+}
+EXPORT_SYMBOL_GPL(nvdimm_provider_data);
+
+struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
+		const struct attribute_group **groups, unsigned long flags)
+{
+	struct nvdimm *nvdimm = kzalloc(sizeof(*nvdimm), GFP_KERNEL);
+	struct device *dev;
+
+	if (!nvdimm)
+		return NULL;
+
+	nvdimm->id = ida_simple_get(&dimm_ida, 0, 0, GFP_KERNEL);
+	if (nvdimm->id < 0) {
+		kfree(nvdimm);
+		return NULL;
+	}
+	nvdimm->provider_data = provider_data;
+	nvdimm->flags = flags;
+
+	dev = &nvdimm->dev;
+	dev_set_name(dev, "nmem%d", nvdimm->id);
+	dev->parent = &nvdimm_bus->dev;
+	dev->type = &nvdimm_device_type;
+	dev->bus = &nvdimm_bus_type;
+	dev->groups = groups;
+	if (device_register(dev) != 0) {
+		put_device(dev);
+		return NULL;
+	}
+
+	return nvdimm;
+}
+EXPORT_SYMBOL_GPL(nvdimm_create);

drivers/nvdimm/nd-core.h

@@ -15,6 +15,10 @@
 #include <linux/libnvdimm.h>
 #include <linux/device.h>
 
+extern struct list_head nvdimm_bus_list;
+extern struct mutex nvdimm_bus_list_mutex;
+extern struct bus_type nvdimm_bus_type;
+
 struct nvdimm_bus {
 	struct nvdimm_bus_descriptor *nd_desc;
 	struct list_head list;
@@ -22,6 +26,14 @@ struct nvdimm_bus {
 	int id;
 };
 
+struct nvdimm {
+	unsigned long flags;
+	void *provider_data;
+	struct device dev;
+	int id;
+};
+
+struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev);
 int __init nvdimm_bus_init(void);
 void __exit nvdimm_bus_exit(void);
 int nvdimm_bus_create_ndctl(struct nvdimm_bus *nvdimm_bus);