xref: /linux/drivers/soc/qcom/rmtfs_mem.c (revision af50e4ba34f4c45e92535364133d4deb5931c1c5)
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 	unsigned int perms;
42 };
43 
44 static ssize_t qcom_rmtfs_mem_show(struct device *dev,
45 			      struct device_attribute *attr,
46 			      char *buf);
47 
48 static DEVICE_ATTR(phys_addr, 0400, qcom_rmtfs_mem_show, NULL);
49 static DEVICE_ATTR(size, 0400, qcom_rmtfs_mem_show, NULL);
50 static DEVICE_ATTR(client_id, 0400, qcom_rmtfs_mem_show, NULL);
51 
52 static 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 
70 static 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 };
76 ATTRIBUTE_GROUPS(qcom_rmtfs_mem);
77 
78 static 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 }
89 static 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 
107 static 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 
126 static 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 
135 static 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 
144 static 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 
153 static 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 
188 	rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
189 					rmtfs_mem->size, MEMREMAP_WC);
190 	if (IS_ERR(rmtfs_mem->base)) {
191 		dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
192 		ret = PTR_ERR(rmtfs_mem->base);
193 		goto put_device;
194 	}
195 
196 	cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
197 	rmtfs_mem->cdev.owner = THIS_MODULE;
198 
199 	dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
200 	rmtfs_mem->dev.id = client_id;
201 	rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
202 
203 	ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
204 	if (ret) {
205 		dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
206 		goto put_device;
207 	}
208 
209 	rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
210 
211 	ret = of_property_read_u32(node, "qcom,vmid", &vmid);
212 	if (ret < 0 && ret != -EINVAL) {
213 		dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
214 		goto remove_cdev;
215 	} else if (!ret) {
216 		perms[0].vmid = QCOM_SCM_VMID_HLOS;
217 		perms[0].perm = QCOM_SCM_PERM_RW;
218 		perms[1].vmid = vmid;
219 		perms[1].perm = QCOM_SCM_PERM_RW;
220 
221 		rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
222 		ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
223 					  &rmtfs_mem->perms, perms, 2);
224 		if (ret < 0) {
225 			dev_err(&pdev->dev, "assign memory failed\n");
226 			goto remove_cdev;
227 		}
228 	}
229 
230 	dev_set_drvdata(&pdev->dev, rmtfs_mem);
231 
232 	return 0;
233 
234 remove_cdev:
235 	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
236 put_device:
237 	put_device(&rmtfs_mem->dev);
238 
239 	return ret;
240 }
241 
242 static int qcom_rmtfs_mem_remove(struct platform_device *pdev)
243 {
244 	struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
245 	struct qcom_scm_vmperm perm;
246 
247 	if (rmtfs_mem->perms) {
248 		perm.vmid = QCOM_SCM_VMID_HLOS;
249 		perm.perm = QCOM_SCM_PERM_RW;
250 
251 		qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
252 				    &rmtfs_mem->perms, &perm, 1);
253 	}
254 
255 	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
256 	put_device(&rmtfs_mem->dev);
257 
258 	return 0;
259 }
260 
261 static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
262 	{ .compatible = "qcom,rmtfs-mem" },
263 	{}
264 };
265 MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
266 
267 static struct platform_driver qcom_rmtfs_mem_driver = {
268 	.probe = qcom_rmtfs_mem_probe,
269 	.remove = qcom_rmtfs_mem_remove,
270 	.driver  = {
271 		.name  = "qcom_rmtfs_mem",
272 		.of_match_table = qcom_rmtfs_mem_of_match,
273 	},
274 };
275 
276 static int qcom_rmtfs_mem_init(void)
277 {
278 	int ret;
279 
280 	ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
281 				  QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
282 	if (ret < 0) {
283 		pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
284 		return ret;
285 	}
286 
287 	ret = platform_driver_register(&qcom_rmtfs_mem_driver);
288 	if (ret < 0) {
289 		pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
290 		unregister_chrdev_region(qcom_rmtfs_mem_major,
291 					 QCOM_RMTFS_MEM_DEV_MAX);
292 	}
293 
294 	return ret;
295 }
296 module_init(qcom_rmtfs_mem_init);
297 
298 static void qcom_rmtfs_mem_exit(void)
299 {
300 	platform_driver_unregister(&qcom_rmtfs_mem_driver);
301 	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
302 }
303 module_exit(qcom_rmtfs_mem_exit);
304 
305 MODULE_AUTHOR("Linaro Ltd");
306 MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver");
307 MODULE_LICENSE("GPL v2");
308