drivers/soc/qcom/rmtfs_mem.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2017 Linaro Ltd.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/cdev.h>
   8 #include <linux/err.h>
   9 #include <linux/module.h>
  10 #include <linux/platform_device.h>
  11 #include <linux/of.h>
  12 #include <linux/of_reserved_mem.h>
  13 #include <linux/dma-mapping.h>
  14 #include <linux/slab.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/io.h>
  17 #include <linux/firmware/qcom/qcom_scm.h>
  18
  19 #define QCOM_RMTFS_MEM_DEV_MAX  (MINORMASK + 1)
  20 #define NUM_MAX_VMIDS           2
  21
  22 static dev_t qcom_rmtfs_mem_major;
  23
  24 struct qcom_rmtfs_mem {
  25         struct device dev;
  26         struct cdev cdev;
  27
  28         void *base;
  29         phys_addr_t addr;
  30         phys_addr_t size;
  31
  32         unsigned int client_id;
  33
  34         u64 perms;
  35 };
  36
  37 static ssize_t qcom_rmtfs_mem_show(struct device *dev,
  38                               struct device_attribute *attr,
  39                               char *buf);
  40
  41 static DEVICE_ATTR(phys_addr, 0444, qcom_rmtfs_mem_show, NULL);
  42 static DEVICE_ATTR(size, 0444, qcom_rmtfs_mem_show, NULL);
  43 static DEVICE_ATTR(client_id, 0444, qcom_rmtfs_mem_show, NULL);
  44
  45 static ssize_t qcom_rmtfs_mem_show(struct device *dev,
  46                               struct device_attribute *attr,
  47                               char *buf)
  48 {
  49         struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
  50                                                         struct qcom_rmtfs_mem,
  51                                                         dev);
  52
  53         if (attr == &dev_attr_phys_addr)
  54                 return sprintf(buf, "%pa\n", &rmtfs_mem->addr);
  55         if (attr == &dev_attr_size)
  56                 return sprintf(buf, "%pa\n", &rmtfs_mem->size);
  57         if (attr == &dev_attr_client_id)
  58                 return sprintf(buf, "%d\n", rmtfs_mem->client_id);
  59
  60         return -EINVAL;
  61 }
  62
  63 static struct attribute *qcom_rmtfs_mem_attrs[] = {
  64         &dev_attr_phys_addr.attr,
  65         &dev_attr_size.attr,
  66         &dev_attr_client_id.attr,
  67         NULL
  68 };
  69 ATTRIBUTE_GROUPS(qcom_rmtfs_mem);
  70
  71 static int qcom_rmtfs_mem_open(struct inode *inode, struct file *filp)
  72 {
  73         struct qcom_rmtfs_mem *rmtfs_mem = container_of(inode->i_cdev,
  74                                                         struct qcom_rmtfs_mem,
  75                                                         cdev);
  76
  77         get_device(&rmtfs_mem->dev);
  78         filp->private_data = rmtfs_mem;
  79
  80         return 0;
  81 }
  82 static ssize_t qcom_rmtfs_mem_read(struct file *filp,
  83                               char __user *buf, size_t count, loff_t *f_pos)
  84 {
  85         struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
  86
  87         if (*f_pos >= rmtfs_mem->size)
  88                 return 0;
  89
  90         if (*f_pos + count >= rmtfs_mem->size)
  91                 count = rmtfs_mem->size - *f_pos;
  92
  93         if (copy_to_user(buf, rmtfs_mem->base + *f_pos, count))
  94                 return -EFAULT;
  95
  96         *f_pos += count;
  97         return count;
  98 }
  99
 100 static ssize_t qcom_rmtfs_mem_write(struct file *filp,
 101                                const char __user *buf, size_t count,
 102                                loff_t *f_pos)
 103 {
 104         struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
 105
 106         if (*f_pos >= rmtfs_mem->size)
 107                 return 0;
 108
 109         if (*f_pos + count >= rmtfs_mem->size)
 110                 count = rmtfs_mem->size - *f_pos;
 111
 112         if (copy_from_user(rmtfs_mem->base + *f_pos, buf, count))
 113                 return -EFAULT;
 114
 115         *f_pos += count;
 116         return count;
 117 }
 118
 119 static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
 120 {
 121         struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
 122
 123         put_device(&rmtfs_mem->dev);
 124
 125         return 0;
 126 }
 127
 128 static struct class rmtfs_class = {
 129         .name           = "rmtfs",
 130 };
 131
 132 static int qcom_rmtfs_mem_mmap(struct file *filep, struct vm_area_struct *vma)
 133 {
 134         struct qcom_rmtfs_mem *rmtfs_mem = filep->private_data;
 135
 136         if (vma->vm_end - vma->vm_start > rmtfs_mem->size) {
 137                 dev_dbg(&rmtfs_mem->dev,
 138                         "vm_end[%lu] - vm_start[%lu] [%lu] > mem->size[%pa]\n",
 139                         vma->vm_end, vma->vm_start,
 140                         (vma->vm_end - vma->vm_start), &rmtfs_mem->size);
 141                 return -EINVAL;
 142         }
 143
 144         vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
 145         return remap_pfn_range(vma,
 146                                vma->vm_start,
 147                                rmtfs_mem->addr >> PAGE_SHIFT,
 148                                vma->vm_end - vma->vm_start,
 149                                vma->vm_page_prot);
 150 }
 151
 152 static const struct file_operations qcom_rmtfs_mem_fops = {
 153         .owner = THIS_MODULE,
 154         .open = qcom_rmtfs_mem_open,
 155         .read = qcom_rmtfs_mem_read,
 156         .write = qcom_rmtfs_mem_write,
 157         .release = qcom_rmtfs_mem_release,
 158         .llseek = default_llseek,
 159         .mmap = qcom_rmtfs_mem_mmap,
 160 };
 161
 162 static void qcom_rmtfs_mem_release_device(struct device *dev)
 163 {
 164         struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
 165                                                         struct qcom_rmtfs_mem,
 166                                                         dev);
 167
 168         kfree(rmtfs_mem);
 169 }
 170
 171 static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 172 {
 173         struct device_node *node = pdev->dev.of_node;
 174         struct qcom_scm_vmperm perms[NUM_MAX_VMIDS + 1];
 175         struct reserved_mem *rmem;
 176         struct qcom_rmtfs_mem *rmtfs_mem;
 177         u32 client_id;
 178         u32 vmid[NUM_MAX_VMIDS];
 179         int num_vmids;
 180         int ret, i;
 181
 182         rmem = of_reserved_mem_lookup(node);
 183         if (!rmem) {
 184                 dev_err(&pdev->dev, "failed to acquire memory region\n");
 185                 return -EINVAL;
 186         }
 187
 188         ret = of_property_read_u32(node, "qcom,client-id", &client_id);
 189         if (ret) {
 190                 dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
 191                 return ret;
 192
 193         }
 194
 195         rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL);
 196         if (!rmtfs_mem)
 197                 return -ENOMEM;
 198
 199         rmtfs_mem->addr = rmem->base;
 200         rmtfs_mem->client_id = client_id;
 201         rmtfs_mem->size = rmem->size;
 202
 203         /*
 204          * If requested, discard the first and last 4k block in order to ensure
 205          * that the rmtfs region isn't adjacent to other protected regions.
 206          */
 207         if (of_property_read_bool(node, "qcom,use-guard-pages")) {
 208                 rmtfs_mem->addr += SZ_4K;
 209                 rmtfs_mem->size -= 2 * SZ_4K;
 210         }
 211
 212         device_initialize(&rmtfs_mem->dev);
 213         rmtfs_mem->dev.parent = &pdev->dev;
 214         rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
 215         rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
 216
 217         rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
 218                                         rmtfs_mem->size, MEMREMAP_WC);
 219         if (IS_ERR(rmtfs_mem->base)) {
 220                 dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
 221                 ret = PTR_ERR(rmtfs_mem->base);
 222                 goto put_device;
 223         }
 224
 225         cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
 226         rmtfs_mem->cdev.owner = THIS_MODULE;
 227
 228         dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
 229         rmtfs_mem->dev.id = client_id;
 230         rmtfs_mem->dev.class = &rmtfs_class;
 231         rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
 232
 233         ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 234         if (ret) {
 235                 dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
 236                 goto put_device;
 237         }
 238
 239         num_vmids = of_property_count_u32_elems(node, "qcom,vmid");
 240         if (num_vmids == -EINVAL) {
 241                 /* qcom,vmid is optional */
 242                 num_vmids = 0;
 243         } else if (num_vmids < 0) {
 244                 dev_err(&pdev->dev, "failed to count qcom,vmid elements: %d\n", num_vmids);
 245                 ret = num_vmids;
 246                 goto remove_cdev;
 247         } else if (num_vmids > NUM_MAX_VMIDS) {
 248                 dev_warn(&pdev->dev,
 249                          "too many VMIDs (%d) specified! Only mapping first %d entries\n",
 250                          num_vmids, NUM_MAX_VMIDS);
 251                 num_vmids = NUM_MAX_VMIDS;
 252         }
 253
 254         ret = of_property_read_u32_array(node, "qcom,vmid", vmid, num_vmids);
 255         if (ret < 0 && ret != -EINVAL) {
 256                 dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
 257                 goto remove_cdev;
 258         } else if (!ret) {
 259                 if (!qcom_scm_is_available()) {
 260                         ret = -EPROBE_DEFER;
 261                         goto remove_cdev;
 262                 }
 263
 264                 perms[0].vmid = QCOM_SCM_VMID_HLOS;
 265                 perms[0].perm = QCOM_SCM_PERM_RW;
 266
 267                 for (i = 0; i < num_vmids; i++) {
 268                         perms[i + 1].vmid = vmid[i];
 269                         perms[i + 1].perm = QCOM_SCM_PERM_RW;
 270                 }
 271
 272                 rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
 273                 ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
 274                                           &rmtfs_mem->perms, perms, num_vmids + 1);
 275                 if (ret < 0) {
 276                         dev_err(&pdev->dev, "assign memory failed\n");
 277                         goto remove_cdev;
 278                 }
 279         }
 280
 281         dev_set_drvdata(&pdev->dev, rmtfs_mem);
 282
 283         return 0;
 284
 285 remove_cdev:
 286         cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 287 put_device:
 288         put_device(&rmtfs_mem->dev);
 289
 290         return ret;
 291 }
 292
 293 static void qcom_rmtfs_mem_remove(struct platform_device *pdev)
 294 {
 295         struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
 296         struct qcom_scm_vmperm perm;
 297
 298         if (rmtfs_mem->perms) {
 299                 perm.vmid = QCOM_SCM_VMID_HLOS;
 300                 perm.perm = QCOM_SCM_PERM_RW;
 301
 302                 qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
 303                                     &rmtfs_mem->perms, &perm, 1);
 304         }
 305
 306         cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 307         put_device(&rmtfs_mem->dev);
 308 }
 309
 310 static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
 311         { .compatible = "qcom,rmtfs-mem" },
 312         {}
 313 };
 314 MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
 315
 316 static struct platform_driver qcom_rmtfs_mem_driver = {
 317         .probe = qcom_rmtfs_mem_probe,
 318         .remove = qcom_rmtfs_mem_remove,
 319         .driver  = {
 320                 .name  = "qcom_rmtfs_mem",
 321                 .of_match_table = qcom_rmtfs_mem_of_match,
 322         },
 323 };
 324
 325 static int __init qcom_rmtfs_mem_init(void)
 326 {
 327         int ret;
 328
 329         ret = class_register(&rmtfs_class);
 330         if (ret)
 331                 return ret;
 332
 333         ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
 334                                   QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
 335         if (ret < 0) {
 336                 pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
 337                 goto unregister_class;
 338         }
 339
 340         ret = platform_driver_register(&qcom_rmtfs_mem_driver);
 341         if (ret < 0) {
 342                 pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
 343                 goto unregister_chrdev;
 344         }
 345
 346         return 0;
 347
 348 unregister_chrdev:
 349         unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
 350 unregister_class:
 351         class_unregister(&rmtfs_class);
 352         return ret;
 353 }
 354 module_init(qcom_rmtfs_mem_init);
 355
 356 static void __exit qcom_rmtfs_mem_exit(void)
 357 {
 358         platform_driver_unregister(&qcom_rmtfs_mem_driver);
 359         unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
 360         class_unregister(&rmtfs_class);
 361 }
 362 module_exit(qcom_rmtfs_mem_exit);
 363
 364 MODULE_AUTHOR("Linaro Ltd");
 365 MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver");
 366 MODULE_LICENSE("GPL v2");