Dan Williams | ab68f26 | 2016-05-18 09:15:08 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright(c) 2016 Intel Corporation. All rights reserved. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of version 2 of the GNU General Public License as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, but |
| 9 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 11 | * General Public License for more details. |
| 12 | */ |
| 13 | #include <linux/pagemap.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/device.h> |
| 16 | #include <linux/pfn_t.h> |
| 17 | #include <linux/slab.h> |
| 18 | #include <linux/dax.h> |
| 19 | #include <linux/fs.h> |
| 20 | #include <linux/mm.h> |
| 21 | |
| 22 | static int dax_major; |
| 23 | static struct class *dax_class; |
| 24 | static DEFINE_IDA(dax_minor_ida); |
| 25 | |
| 26 | /** |
| 27 | * struct dax_region - mapping infrastructure for dax devices |
| 28 | * @id: kernel-wide unique region for a memory range |
| 29 | * @base: linear address corresponding to @res |
| 30 | * @kref: to pin while other agents have a need to do lookups |
| 31 | * @dev: parent device backing this region |
| 32 | * @align: allocation and mapping alignment for child dax devices |
| 33 | * @res: physical address range of the region |
| 34 | * @pfn_flags: identify whether the pfns are paged back or not |
| 35 | */ |
| 36 | struct dax_region { |
| 37 | int id; |
| 38 | struct ida ida; |
| 39 | void *base; |
| 40 | struct kref kref; |
| 41 | struct device *dev; |
| 42 | unsigned int align; |
| 43 | struct resource res; |
| 44 | unsigned long pfn_flags; |
| 45 | }; |
| 46 | |
| 47 | /** |
| 48 | * struct dax_dev - subdivision of a dax region |
| 49 | * @region - parent region |
| 50 | * @dev - device backing the character device |
| 51 | * @kref - enable this data to be tracked in filp->private_data |
| 52 | * @id - child id in the region |
| 53 | * @num_resources - number of physical address extents in this device |
| 54 | * @res - array of physical address ranges |
| 55 | */ |
| 56 | struct dax_dev { |
| 57 | struct dax_region *region; |
| 58 | struct device *dev; |
| 59 | struct kref kref; |
| 60 | int id; |
| 61 | int num_resources; |
| 62 | struct resource res[0]; |
| 63 | }; |
| 64 | |
| 65 | static void dax_region_free(struct kref *kref) |
| 66 | { |
| 67 | struct dax_region *dax_region; |
| 68 | |
| 69 | dax_region = container_of(kref, struct dax_region, kref); |
| 70 | kfree(dax_region); |
| 71 | } |
| 72 | |
| 73 | void dax_region_put(struct dax_region *dax_region) |
| 74 | { |
| 75 | kref_put(&dax_region->kref, dax_region_free); |
| 76 | } |
| 77 | EXPORT_SYMBOL_GPL(dax_region_put); |
| 78 | |
| 79 | static void dax_dev_free(struct kref *kref) |
| 80 | { |
| 81 | struct dax_dev *dax_dev; |
| 82 | |
| 83 | dax_dev = container_of(kref, struct dax_dev, kref); |
| 84 | dax_region_put(dax_dev->region); |
| 85 | kfree(dax_dev); |
| 86 | } |
| 87 | |
| 88 | static void dax_dev_put(struct dax_dev *dax_dev) |
| 89 | { |
| 90 | kref_put(&dax_dev->kref, dax_dev_free); |
| 91 | } |
| 92 | |
| 93 | struct dax_region *alloc_dax_region(struct device *parent, int region_id, |
| 94 | struct resource *res, unsigned int align, void *addr, |
| 95 | unsigned long pfn_flags) |
| 96 | { |
| 97 | struct dax_region *dax_region; |
| 98 | |
| 99 | dax_region = kzalloc(sizeof(*dax_region), GFP_KERNEL); |
| 100 | |
| 101 | if (!dax_region) |
| 102 | return NULL; |
| 103 | |
| 104 | memcpy(&dax_region->res, res, sizeof(*res)); |
| 105 | dax_region->pfn_flags = pfn_flags; |
| 106 | kref_init(&dax_region->kref); |
| 107 | dax_region->id = region_id; |
| 108 | ida_init(&dax_region->ida); |
| 109 | dax_region->align = align; |
| 110 | dax_region->dev = parent; |
| 111 | dax_region->base = addr; |
| 112 | |
| 113 | return dax_region; |
| 114 | } |
| 115 | EXPORT_SYMBOL_GPL(alloc_dax_region); |
| 116 | |
| 117 | static ssize_t size_show(struct device *dev, |
| 118 | struct device_attribute *attr, char *buf) |
| 119 | { |
| 120 | struct dax_dev *dax_dev = dev_get_drvdata(dev); |
| 121 | unsigned long long size = 0; |
| 122 | int i; |
| 123 | |
| 124 | for (i = 0; i < dax_dev->num_resources; i++) |
| 125 | size += resource_size(&dax_dev->res[i]); |
| 126 | |
| 127 | return sprintf(buf, "%llu\n", size); |
| 128 | } |
| 129 | static DEVICE_ATTR_RO(size); |
| 130 | |
| 131 | static struct attribute *dax_device_attributes[] = { |
| 132 | &dev_attr_size.attr, |
| 133 | NULL, |
| 134 | }; |
| 135 | |
| 136 | static const struct attribute_group dax_device_attribute_group = { |
| 137 | .attrs = dax_device_attributes, |
| 138 | }; |
| 139 | |
| 140 | static const struct attribute_group *dax_attribute_groups[] = { |
| 141 | &dax_device_attribute_group, |
| 142 | NULL, |
| 143 | }; |
| 144 | |
| 145 | static void unregister_dax_dev(void *_dev) |
| 146 | { |
| 147 | struct device *dev = _dev; |
| 148 | struct dax_dev *dax_dev = dev_get_drvdata(dev); |
| 149 | struct dax_region *dax_region = dax_dev->region; |
| 150 | |
| 151 | dev_dbg(dev, "%s\n", __func__); |
| 152 | |
| 153 | get_device(dev); |
| 154 | device_unregister(dev); |
| 155 | ida_simple_remove(&dax_region->ida, dax_dev->id); |
| 156 | ida_simple_remove(&dax_minor_ida, MINOR(dev->devt)); |
| 157 | put_device(dev); |
| 158 | dax_dev_put(dax_dev); |
| 159 | } |
| 160 | |
| 161 | int devm_create_dax_dev(struct dax_region *dax_region, struct resource *res, |
| 162 | int count) |
| 163 | { |
| 164 | struct device *parent = dax_region->dev; |
| 165 | struct dax_dev *dax_dev; |
| 166 | struct device *dev; |
| 167 | int rc, minor; |
| 168 | dev_t dev_t; |
| 169 | |
| 170 | dax_dev = kzalloc(sizeof(*dax_dev) + sizeof(*res) * count, GFP_KERNEL); |
| 171 | if (!dax_dev) |
| 172 | return -ENOMEM; |
| 173 | memcpy(dax_dev->res, res, sizeof(*res) * count); |
| 174 | dax_dev->num_resources = count; |
| 175 | kref_init(&dax_dev->kref); |
| 176 | dax_dev->region = dax_region; |
| 177 | kref_get(&dax_region->kref); |
| 178 | |
| 179 | dax_dev->id = ida_simple_get(&dax_region->ida, 0, 0, GFP_KERNEL); |
| 180 | if (dax_dev->id < 0) { |
| 181 | rc = dax_dev->id; |
| 182 | goto err_id; |
| 183 | } |
| 184 | |
| 185 | minor = ida_simple_get(&dax_minor_ida, 0, 0, GFP_KERNEL); |
| 186 | if (minor < 0) { |
| 187 | rc = minor; |
| 188 | goto err_minor; |
| 189 | } |
| 190 | |
| 191 | dev_t = MKDEV(dax_major, minor); |
| 192 | dev = device_create_with_groups(dax_class, parent, dev_t, dax_dev, |
| 193 | dax_attribute_groups, "dax%d.%d", dax_region->id, |
| 194 | dax_dev->id); |
| 195 | if (IS_ERR(dev)) { |
| 196 | rc = PTR_ERR(dev); |
| 197 | goto err_create; |
| 198 | } |
| 199 | dax_dev->dev = dev; |
| 200 | |
| 201 | rc = devm_add_action(dax_region->dev, unregister_dax_dev, dev); |
| 202 | if (rc) { |
| 203 | unregister_dax_dev(dev); |
| 204 | return rc; |
| 205 | } |
| 206 | |
| 207 | return 0; |
| 208 | |
| 209 | err_create: |
| 210 | ida_simple_remove(&dax_minor_ida, minor); |
| 211 | err_minor: |
| 212 | ida_simple_remove(&dax_region->ida, dax_dev->id); |
| 213 | err_id: |
| 214 | dax_dev_put(dax_dev); |
| 215 | |
| 216 | return rc; |
| 217 | } |
| 218 | EXPORT_SYMBOL_GPL(devm_create_dax_dev); |
| 219 | |
| 220 | static const struct file_operations dax_fops = { |
| 221 | .llseek = noop_llseek, |
| 222 | .owner = THIS_MODULE, |
| 223 | }; |
| 224 | |
| 225 | static int __init dax_init(void) |
| 226 | { |
| 227 | int rc; |
| 228 | |
| 229 | rc = register_chrdev(0, "dax", &dax_fops); |
| 230 | if (rc < 0) |
| 231 | return rc; |
| 232 | dax_major = rc; |
| 233 | |
| 234 | dax_class = class_create(THIS_MODULE, "dax"); |
| 235 | if (IS_ERR(dax_class)) { |
| 236 | unregister_chrdev(dax_major, "dax"); |
| 237 | return PTR_ERR(dax_class); |
| 238 | } |
| 239 | |
| 240 | return 0; |
| 241 | } |
| 242 | |
| 243 | static void __exit dax_exit(void) |
| 244 | { |
| 245 | class_destroy(dax_class); |
| 246 | unregister_chrdev(dax_major, "dax"); |
| 247 | ida_destroy(&dax_minor_ida); |
| 248 | } |
| 249 | |
| 250 | MODULE_AUTHOR("Intel Corporation"); |
| 251 | MODULE_LICENSE("GPL v2"); |
| 252 | subsys_initcall(dax_init); |
| 253 | module_exit(dax_exit); |