--- /dev/null
+/*
+ * Copyright(c) 2016 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.
+ */
+#include <linux/pagemap.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/pfn_t.h>
+#include <linux/slab.h>
+#include <linux/dax.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+
+static int dax_major;
+static struct class *dax_class;
+static DEFINE_IDA(dax_minor_ida);
+
+/**
+ * struct dax_region - mapping infrastructure for dax devices
+ * @id: kernel-wide unique region for a memory range
+ * @base: linear address corresponding to @res
+ * @kref: to pin while other agents have a need to do lookups
+ * @dev: parent device backing this region
+ * @align: allocation and mapping alignment for child dax devices
+ * @res: physical address range of the region
+ * @pfn_flags: identify whether the pfns are paged back or not
+ */
+struct dax_region {
+ int id;
+ struct ida ida;
+ void *base;
+ struct kref kref;
+ struct device *dev;
+ unsigned int align;
+ struct resource res;
+ unsigned long pfn_flags;
+};
+
+/**
+ * struct dax_dev - subdivision of a dax region
+ * @region - parent region
+ * @dev - device backing the character device
+ * @kref - enable this data to be tracked in filp->private_data
+ * @id - child id in the region
+ * @num_resources - number of physical address extents in this device
+ * @res - array of physical address ranges
+ */
+struct dax_dev {
+ struct dax_region *region;
+ struct device *dev;
+ struct kref kref;
+ int id;
+ int num_resources;
+ struct resource res[0];
+};
+
+static void dax_region_free(struct kref *kref)
+{
+ struct dax_region *dax_region;
+
+ dax_region = container_of(kref, struct dax_region, kref);
+ kfree(dax_region);
+}
+
+void dax_region_put(struct dax_region *dax_region)
+{
+ kref_put(&dax_region->kref, dax_region_free);
+}
+EXPORT_SYMBOL_GPL(dax_region_put);
+
+static void dax_dev_free(struct kref *kref)
+{
+ struct dax_dev *dax_dev;
+
+ dax_dev = container_of(kref, struct dax_dev, kref);
+ dax_region_put(dax_dev->region);
+ kfree(dax_dev);
+}
+
+static void dax_dev_put(struct dax_dev *dax_dev)
+{
+ kref_put(&dax_dev->kref, dax_dev_free);
+}
+
+struct dax_region *alloc_dax_region(struct device *parent, int region_id,
+ struct resource *res, unsigned int align, void *addr,
+ unsigned long pfn_flags)
+{
+ struct dax_region *dax_region;
+
+ dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL);
+
+ if (!dax_region)
+ return NULL;
+
+ memcpy(&dax_region->res, res, sizeof(*res));
+ dax_region->pfn_flags = pfn_flags;
+ kref_init(&dax_region->kref);
+ dax_region->id = region_id;
+ ida_init(&dax_region->ida);
+ dax_region->align = align;
+ dax_region->dev = parent;
+ dax_region->base = addr;
+
+ return dax_region;
+}
+EXPORT_SYMBOL_GPL(alloc_dax_region);
+
+static ssize_t size_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dax_dev *dax_dev = dev_get_drvdata(dev);
+ unsigned long long size = 0;
+ int i;
+
+ for (i = 0; i < dax_dev->num_resources; i++)
+ size += resource_size(&dax_dev->res[i]);
+
+ return sprintf(buf, "%llu\n", size);
+}
+static DEVICE_ATTR_RO(size);
+
+static struct attribute *dax_device_attributes[] = {
+ &dev_attr_size.attr,
+ NULL,
+};
+
+static const struct attribute_group dax_device_attribute_group = {
+ .attrs = dax_device_attributes,
+};
+
+static const struct attribute_group *dax_attribute_groups[] = {
+ &dax_device_attribute_group,
+ NULL,
+};
+
+static void unregister_dax_dev(void *_dev)
+{
+ struct device *dev = _dev;
+ struct dax_dev *dax_dev = dev_get_drvdata(dev);
+ struct dax_region *dax_region = dax_dev->region;
+
+ dev_dbg(dev, "%s\n", __func__);
+
+ get_device(dev);
+ device_unregister(dev);
+ ida_simple_remove(&dax_region->ida, dax_dev->id);
+ ida_simple_remove(&dax_minor_ida, MINOR(dev->devt));
+ put_device(dev);
+ dax_dev_put(dax_dev);
+}
+
+int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res,
+ int count)
+{
+ struct device *parent = dax_region->dev;
+ struct dax_dev *dax_dev;
+ struct device *dev;
+ int rc, minor;
+ dev_t dev_t;
+
+ dax_dev = kzalloc(sizeof(*dax_dev) + sizeof(*res) * count, GFP_KERNEL);
+ if (!dax_dev)
+ return -ENOMEM;
+ memcpy(dax_dev->res, res, sizeof(*res) * count);
+ dax_dev->num_resources = count;
+ kref_init(&dax_dev->kref);
+ dax_dev->region = dax_region;
+ kref_get(&dax_region->kref);
+
+ dax_dev->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL);
+ if (dax_dev->id < 0) {
+ rc = dax_dev->id;
+ goto err_id;
+ }
+
+ minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL);
+ if (minor < 0) {
+ rc = minor;
+ goto err_minor;
+ }
+
+ dev_t = MKDEV(dax_major, minor);
+ dev = device_create_with_groups(dax_class, parent, dev_t, dax_dev,
+ dax_attribute_groups, "dax%d.%d", dax_region->id,
+ dax_dev->id);
+ if (IS_ERR(dev)) {
+ rc = PTR_ERR(dev);
+ goto err_create;
+ }
+ dax_dev->dev = dev;
+
+ rc = devm_add_action(dax_region->dev, unregister_dax_dev, dev);
+ if (rc) {
+ unregister_dax_dev(dev);
+ return rc;
+ }
+
+ return 0;
+
+ err_create:
+ ida_simple_remove(&dax_minor_ida, minor);
+ err_minor:
+ ida_simple_remove(&dax_region->ida, dax_dev->id);
+ err_id:
+ dax_dev_put(dax_dev);
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(devm_create_dax_dev);
+
+static const struct file_operations dax_fops = {
+ .llseek = noop_llseek,
+ .owner = THIS_MODULE,
+};
+
+static int __init dax_init(void)
+{
+ int rc;
+
+ rc = register_chrdev(0, "dax", &dax_fops);
+ if (rc < 0)
+ return rc;
+ dax_major = rc;
+
+ dax_class = class_create(THIS_MODULE, "dax");
+ if (IS_ERR(dax_class)) {
+ unregister_chrdev(dax_major, "dax");
+ return PTR_ERR(dax_class);
+ }
+
+ return 0;
+}
+
+static void __exit dax_exit(void)
+{
+ class_destroy(dax_class);
+ unregister_chrdev(dax_major, "dax");
+ ida_destroy(&dax_minor_ida);
+}
+
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");
+subsys_initcall(dax_init);
+module_exit(dax_exit);
projects / cascardo / linux.git / blobdiff