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 29 static dev_t qcom_rmtfs_mem_major; 30 31 struct 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 42 static ssize_t qcom_rmtfs_mem_show(struct device *dev, 43 struct device_attribute *attr, 44 char *buf); 45 46 static DEVICE_ATTR(phys_addr, 0400, qcom_rmtfs_mem_show, NULL); 47 static DEVICE_ATTR(size, 0400, qcom_rmtfs_mem_show, NULL); 48 static DEVICE_ATTR(client_id, 0400, qcom_rmtfs_mem_show, NULL); 49 50 static ssize_t qcom_rmtfs_mem_show(struct device *dev, 51 struct device_attribute *attr, 52 char *buf) 53 { 54 struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev, 55 struct qcom_rmtfs_mem, 56 dev); 57 58 if (attr == &dev_attr_phys_addr) 59 return sprintf(buf, "%pa\n", &rmtfs_mem->addr); 60 if (attr == &dev_attr_size) 61 return sprintf(buf, "%pa\n", &rmtfs_mem->size); 62 if (attr == &dev_attr_client_id) 63 return sprintf(buf, "%d\n", rmtfs_mem->client_id); 64 65 return -EINVAL; 66 } 67 68 static struct attribute *qcom_rmtfs_mem_attrs[] = { 69 &dev_attr_phys_addr.attr, 70 &dev_attr_size.attr, 71 &dev_attr_client_id.attr, 72 NULL 73 }; 74 ATTRIBUTE_GROUPS(qcom_rmtfs_mem); 75 76 static int qcom_rmtfs_mem_open(struct inode *inode, struct file *filp) 77 { 78 struct qcom_rmtfs_mem *rmtfs_mem = container_of(inode->i_cdev, 79 struct qcom_rmtfs_mem, 80 cdev); 81 82 get_device(&rmtfs_mem->dev); 83 filp->private_data = rmtfs_mem; 84 85 return 0; 86 } 87 static ssize_t qcom_rmtfs_mem_read(struct file *filp, 88 char __user *buf, size_t count, loff_t *f_pos) 89 { 90 struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data; 91 92 if (*f_pos >= rmtfs_mem->size) 93 return 0; 94 95 if (*f_pos + count >= rmtfs_mem->size) 96 count = rmtfs_mem->size - *f_pos; 97 98 if (copy_to_user(buf, rmtfs_mem->base + *f_pos, count)) 99 return -EFAULT; 100 101 *f_pos += count; 102 return count; 103 } 104 105 static ssize_t qcom_rmtfs_mem_write(struct file *filp, 106 const char __user *buf, size_t count, 107 loff_t *f_pos) 108 { 109 struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data; 110 111 if (*f_pos >= rmtfs_mem->size) 112 return 0; 113 114 if (*f_pos + count >= rmtfs_mem->size) 115 count = rmtfs_mem->size - *f_pos; 116 117 if (copy_from_user(rmtfs_mem->base + *f_pos, buf, count)) 118 return -EFAULT; 119 120 *f_pos += count; 121 return count; 122 } 123 124 static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp) 125 { 126 struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data; 127 128 put_device(&rmtfs_mem->dev); 129 130 return 0; 131 } 132 133 static const struct file_operations qcom_rmtfs_mem_fops = { 134 .owner = THIS_MODULE, 135 .open = qcom_rmtfs_mem_open, 136 .read = qcom_rmtfs_mem_read, 137 .write = qcom_rmtfs_mem_write, 138 .release = qcom_rmtfs_mem_release, 139 .llseek = default_llseek, 140 }; 141 142 static void qcom_rmtfs_mem_release_device(struct device *dev) 143 { 144 struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev, 145 struct qcom_rmtfs_mem, 146 dev); 147 148 kfree(rmtfs_mem); 149 } 150 151 static int qcom_rmtfs_mem_probe(struct platform_device *pdev) 152 { 153 struct device_node *node = pdev->dev.of_node; 154 struct reserved_mem *rmem; 155 struct qcom_rmtfs_mem *rmtfs_mem; 156 u32 client_id; 157 int ret; 158 159 rmem = of_reserved_mem_lookup(node); 160 if (!rmem) { 161 dev_err(&pdev->dev, "failed to acquire memory region\n"); 162 return -EINVAL; 163 } 164 165 ret = of_property_read_u32(node, "qcom,client-id", &client_id); 166 if (ret) { 167 dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n"); 168 return ret; 169 170 } 171 172 rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL); 173 if (!rmtfs_mem) 174 return -ENOMEM; 175 176 rmtfs_mem->addr = rmem->base; 177 rmtfs_mem->client_id = client_id; 178 rmtfs_mem->size = rmem->size; 179 180 device_initialize(&rmtfs_mem->dev); 181 rmtfs_mem->dev.parent = &pdev->dev; 182 rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups; 183 184 rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr, 185 rmtfs_mem->size, MEMREMAP_WC); 186 if (IS_ERR(rmtfs_mem->base)) { 187 dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n"); 188 ret = PTR_ERR(rmtfs_mem->base); 189 goto put_device; 190 } 191 192 cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops); 193 rmtfs_mem->cdev.owner = THIS_MODULE; 194 195 dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id); 196 rmtfs_mem->dev.id = client_id; 197 rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id); 198 199 ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev); 200 if (ret) { 201 dev_err(&pdev->dev, "failed to add cdev: %d\n", ret); 202 goto put_device; 203 } 204 205 rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device; 206 207 dev_set_drvdata(&pdev->dev, rmtfs_mem); 208 209 return 0; 210 211 put_device: 212 put_device(&rmtfs_mem->dev); 213 214 return ret; 215 } 216 217 static int qcom_rmtfs_mem_remove(struct platform_device *pdev) 218 { 219 struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev); 220 221 cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev); 222 put_device(&rmtfs_mem->dev); 223 224 return 0; 225 } 226 227 static const struct of_device_id qcom_rmtfs_mem_of_match[] = { 228 { .compatible = "qcom,rmtfs-mem" }, 229 {} 230 }; 231 MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match); 232 233 static struct platform_driver qcom_rmtfs_mem_driver = { 234 .probe = qcom_rmtfs_mem_probe, 235 .remove = qcom_rmtfs_mem_remove, 236 .driver = { 237 .name = "qcom_rmtfs_mem", 238 .of_match_table = qcom_rmtfs_mem_of_match, 239 }, 240 }; 241 242 static int qcom_rmtfs_mem_init(void) 243 { 244 int ret; 245 246 ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0, 247 QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem"); 248 if (ret < 0) { 249 pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n"); 250 return ret; 251 } 252 253 ret = platform_driver_register(&qcom_rmtfs_mem_driver); 254 if (ret < 0) { 255 pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n"); 256 unregister_chrdev_region(qcom_rmtfs_mem_major, 257 QCOM_RMTFS_MEM_DEV_MAX); 258 } 259 260 return ret; 261 } 262 module_init(qcom_rmtfs_mem_init); 263 264 static void qcom_rmtfs_mem_exit(void) 265 { 266 platform_driver_unregister(&qcom_rmtfs_mem_driver); 267 unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX); 268 } 269 module_exit(qcom_rmtfs_mem_exit); 270 271 MODULE_AUTHOR("Linaro Ltd"); 272 MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver"); 273 MODULE_LICENSE("GPL v2"); 274