linux/drivers/soc/qcom/rmtfs_mem.c
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   1/*
   2 * Copyright (c) 2017 Linaro Ltd.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 and
   6 * only version 2 as published by the Free Software Foundation.
   7 *
   8 * This program is distributed in the hope that it will be useful,
   9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 * GNU General Public License for more details.
  12 */
  13
  14#include <linux/kernel.h>
  15#include <linux/cdev.h>
  16#include <linux/err.h>
  17#include <linux/module.h>
  18#include <linux/platform_device.h>
  19#include <linux/of.h>
  20#include <linux/of_reserved_mem.h>
  21#include <linux/dma-mapping.h>
  22#include <linux/slab.h>
  23#include <linux/uaccess.h>
  24#include <linux/io.h>
  25#include <linux/qcom_scm.h>
  26
  27#define QCOM_RMTFS_MEM_DEV_MAX  (MINORMASK + 1)
  28
  29static dev_t qcom_rmtfs_mem_major;
  30
  31struct qcom_rmtfs_mem {
  32        struct device dev;
  33        struct cdev cdev;
  34
  35        void *base;
  36        phys_addr_t addr;
  37        phys_addr_t size;
  38
  39        unsigned int client_id;
  40
  41        unsigned int perms;
  42};
  43
  44static ssize_t qcom_rmtfs_mem_show(struct device *dev,
  45                              struct device_attribute *attr,
  46                              char *buf);
  47
  48static DEVICE_ATTR(phys_addr, 0400, qcom_rmtfs_mem_show, NULL);
  49static DEVICE_ATTR(size, 0400, qcom_rmtfs_mem_show, NULL);
  50static DEVICE_ATTR(client_id, 0400, qcom_rmtfs_mem_show, NULL);
  51
  52static ssize_t qcom_rmtfs_mem_show(struct device *dev,
  53                              struct device_attribute *attr,
  54                              char *buf)
  55{
  56        struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
  57                                                        struct qcom_rmtfs_mem,
  58                                                        dev);
  59
  60        if (attr == &dev_attr_phys_addr)
  61                return sprintf(buf, "%pa\n", &rmtfs_mem->addr);
  62        if (attr == &dev_attr_size)
  63                return sprintf(buf, "%pa\n", &rmtfs_mem->size);
  64        if (attr == &dev_attr_client_id)
  65                return sprintf(buf, "%d\n", rmtfs_mem->client_id);
  66
  67        return -EINVAL;
  68}
  69
  70static struct attribute *qcom_rmtfs_mem_attrs[] = {
  71        &dev_attr_phys_addr.attr,
  72        &dev_attr_size.attr,
  73        &dev_attr_client_id.attr,
  74        NULL
  75};
  76ATTRIBUTE_GROUPS(qcom_rmtfs_mem);
  77
  78static int qcom_rmtfs_mem_open(struct inode *inode, struct file *filp)
  79{
  80        struct qcom_rmtfs_mem *rmtfs_mem = container_of(inode->i_cdev,
  81                                                        struct qcom_rmtfs_mem,
  82                                                        cdev);
  83
  84        get_device(&rmtfs_mem->dev);
  85        filp->private_data = rmtfs_mem;
  86
  87        return 0;
  88}
  89static ssize_t qcom_rmtfs_mem_read(struct file *filp,
  90                              char __user *buf, size_t count, loff_t *f_pos)
  91{
  92        struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
  93
  94        if (*f_pos >= rmtfs_mem->size)
  95                return 0;
  96
  97        if (*f_pos + count >= rmtfs_mem->size)
  98                count = rmtfs_mem->size - *f_pos;
  99
 100        if (copy_to_user(buf, rmtfs_mem->base + *f_pos, count))
 101                return -EFAULT;
 102
 103        *f_pos += count;
 104        return count;
 105}
 106
 107static ssize_t qcom_rmtfs_mem_write(struct file *filp,
 108                               const char __user *buf, size_t count,
 109                               loff_t *f_pos)
 110{
 111        struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
 112
 113        if (*f_pos >= rmtfs_mem->size)
 114                return 0;
 115
 116        if (*f_pos + count >= rmtfs_mem->size)
 117                count = rmtfs_mem->size - *f_pos;
 118
 119        if (copy_from_user(rmtfs_mem->base + *f_pos, buf, count))
 120                return -EFAULT;
 121
 122        *f_pos += count;
 123        return count;
 124}
 125
 126static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
 127{
 128        struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
 129
 130        put_device(&rmtfs_mem->dev);
 131
 132        return 0;
 133}
 134
 135static const struct file_operations qcom_rmtfs_mem_fops = {
 136        .owner = THIS_MODULE,
 137        .open = qcom_rmtfs_mem_open,
 138        .read = qcom_rmtfs_mem_read,
 139        .write = qcom_rmtfs_mem_write,
 140        .release = qcom_rmtfs_mem_release,
 141        .llseek = default_llseek,
 142};
 143
 144static void qcom_rmtfs_mem_release_device(struct device *dev)
 145{
 146        struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
 147                                                        struct qcom_rmtfs_mem,
 148                                                        dev);
 149
 150        kfree(rmtfs_mem);
 151}
 152
 153static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
 154{
 155        struct device_node *node = pdev->dev.of_node;
 156        struct qcom_scm_vmperm perms[2];
 157        struct reserved_mem *rmem;
 158        struct qcom_rmtfs_mem *rmtfs_mem;
 159        u32 client_id;
 160        u32 vmid;
 161        int ret;
 162
 163        rmem = of_reserved_mem_lookup(node);
 164        if (!rmem) {
 165                dev_err(&pdev->dev, "failed to acquire memory region\n");
 166                return -EINVAL;
 167        }
 168
 169        ret = of_property_read_u32(node, "qcom,client-id", &client_id);
 170        if (ret) {
 171                dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
 172                return ret;
 173
 174        }
 175
 176        rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL);
 177        if (!rmtfs_mem)
 178                return -ENOMEM;
 179
 180        rmtfs_mem->addr = rmem->base;
 181        rmtfs_mem->client_id = client_id;
 182        rmtfs_mem->size = rmem->size;
 183
 184        device_initialize(&rmtfs_mem->dev);
 185        rmtfs_mem->dev.parent = &pdev->dev;
 186        rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
 187        rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
 188
 189        rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
 190                                        rmtfs_mem->size, MEMREMAP_WC);
 191        if (IS_ERR(rmtfs_mem->base)) {
 192                dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
 193                ret = PTR_ERR(rmtfs_mem->base);
 194                goto put_device;
 195        }
 196
 197        cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
 198        rmtfs_mem->cdev.owner = THIS_MODULE;
 199
 200        dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
 201        rmtfs_mem->dev.id = client_id;
 202        rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
 203
 204        ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 205        if (ret) {
 206                dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
 207                goto put_device;
 208        }
 209
 210        ret = of_property_read_u32(node, "qcom,vmid", &vmid);
 211        if (ret < 0 && ret != -EINVAL) {
 212                dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
 213                goto remove_cdev;
 214        } else if (!ret) {
 215                perms[0].vmid = QCOM_SCM_VMID_HLOS;
 216                perms[0].perm = QCOM_SCM_PERM_RW;
 217                perms[1].vmid = vmid;
 218                perms[1].perm = QCOM_SCM_PERM_RW;
 219
 220                rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
 221                ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
 222                                          &rmtfs_mem->perms, perms, 2);
 223                if (ret < 0) {
 224                        dev_err(&pdev->dev, "assign memory failed\n");
 225                        goto remove_cdev;
 226                }
 227        }
 228
 229        dev_set_drvdata(&pdev->dev, rmtfs_mem);
 230
 231        return 0;
 232
 233remove_cdev:
 234        cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 235put_device:
 236        put_device(&rmtfs_mem->dev);
 237
 238        return ret;
 239}
 240
 241static int qcom_rmtfs_mem_remove(struct platform_device *pdev)
 242{
 243        struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
 244        struct qcom_scm_vmperm perm;
 245
 246        if (rmtfs_mem->perms) {
 247                perm.vmid = QCOM_SCM_VMID_HLOS;
 248                perm.perm = QCOM_SCM_PERM_RW;
 249
 250                qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
 251                                    &rmtfs_mem->perms, &perm, 1);
 252        }
 253
 254        cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
 255        put_device(&rmtfs_mem->dev);
 256
 257        return 0;
 258}
 259
 260static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
 261        { .compatible = "qcom,rmtfs-mem" },
 262        {}
 263};
 264MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
 265
 266static struct platform_driver qcom_rmtfs_mem_driver = {
 267        .probe = qcom_rmtfs_mem_probe,
 268        .remove = qcom_rmtfs_mem_remove,
 269        .driver  = {
 270                .name  = "qcom_rmtfs_mem",
 271                .of_match_table = qcom_rmtfs_mem_of_match,
 272        },
 273};
 274
 275static int qcom_rmtfs_mem_init(void)
 276{
 277        int ret;
 278
 279        ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
 280                                  QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
 281        if (ret < 0) {
 282                pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
 283                return ret;
 284        }
 285
 286        ret = platform_driver_register(&qcom_rmtfs_mem_driver);
 287        if (ret < 0) {
 288                pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
 289                unregister_chrdev_region(qcom_rmtfs_mem_major,
 290                                         QCOM_RMTFS_MEM_DEV_MAX);
 291        }
 292
 293        return ret;
 294}
 295module_init(qcom_rmtfs_mem_init);
 296
 297static void qcom_rmtfs_mem_exit(void)
 298{
 299        platform_driver_unregister(&qcom_rmtfs_mem_driver);
 300        unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
 301}
 302module_exit(qcom_rmtfs_mem_exit);
 303
 304MODULE_AUTHOR("Linaro Ltd");
 305MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver");
 306MODULE_LICENSE("GPL v2");
 307