xref: /openbmc/linux/drivers/soc/qcom/rmtfs_mem.c (revision 4fc4dca8)
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, 0444, qcom_rmtfs_mem_show, NULL);
49 static DEVICE_ATTR(size, 0444, qcom_rmtfs_mem_show, NULL);
50 static DEVICE_ATTR(client_id, 0444, 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 struct class rmtfs_class = {
136 	.owner          = THIS_MODULE,
137 	.name           = "rmtfs",
138 };
139 
140 static int qcom_rmtfs_mem_mmap(struct file *filep, struct vm_area_struct *vma)
141 {
142 	struct qcom_rmtfs_mem *rmtfs_mem = filep->private_data;
143 
144 	if (vma->vm_end - vma->vm_start > rmtfs_mem->size) {
145 		dev_dbg(&rmtfs_mem->dev,
146 			"vm_end[%lu] - vm_start[%lu] [%lu] > mem->size[%pa]\n",
147 			vma->vm_end, vma->vm_start,
148 			(vma->vm_end - vma->vm_start), &rmtfs_mem->size);
149 		return -EINVAL;
150 	}
151 
152 	vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
153 	return remap_pfn_range(vma,
154 			       vma->vm_start,
155 			       rmtfs_mem->addr >> PAGE_SHIFT,
156 			       vma->vm_end - vma->vm_start,
157 			       vma->vm_page_prot);
158 }
159 
160 static const struct file_operations qcom_rmtfs_mem_fops = {
161 	.owner = THIS_MODULE,
162 	.open = qcom_rmtfs_mem_open,
163 	.read = qcom_rmtfs_mem_read,
164 	.write = qcom_rmtfs_mem_write,
165 	.release = qcom_rmtfs_mem_release,
166 	.llseek = default_llseek,
167 	.mmap = qcom_rmtfs_mem_mmap,
168 };
169 
170 static void qcom_rmtfs_mem_release_device(struct device *dev)
171 {
172 	struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
173 							struct qcom_rmtfs_mem,
174 							dev);
175 
176 	kfree(rmtfs_mem);
177 }
178 
179 static int qcom_rmtfs_mem_probe(struct platform_device *pdev)
180 {
181 	struct device_node *node = pdev->dev.of_node;
182 	struct qcom_scm_vmperm perms[2];
183 	struct reserved_mem *rmem;
184 	struct qcom_rmtfs_mem *rmtfs_mem;
185 	u32 client_id;
186 	u32 vmid;
187 	int ret;
188 
189 	rmem = of_reserved_mem_lookup(node);
190 	if (!rmem) {
191 		dev_err(&pdev->dev, "failed to acquire memory region\n");
192 		return -EINVAL;
193 	}
194 
195 	ret = of_property_read_u32(node, "qcom,client-id", &client_id);
196 	if (ret) {
197 		dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
198 		return ret;
199 
200 	}
201 
202 	rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL);
203 	if (!rmtfs_mem)
204 		return -ENOMEM;
205 
206 	rmtfs_mem->addr = rmem->base;
207 	rmtfs_mem->client_id = client_id;
208 	rmtfs_mem->size = rmem->size;
209 
210 	device_initialize(&rmtfs_mem->dev);
211 	rmtfs_mem->dev.parent = &pdev->dev;
212 	rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
213 	rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
214 
215 	rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
216 					rmtfs_mem->size, MEMREMAP_WC);
217 	if (IS_ERR(rmtfs_mem->base)) {
218 		dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
219 		ret = PTR_ERR(rmtfs_mem->base);
220 		goto put_device;
221 	}
222 
223 	cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
224 	rmtfs_mem->cdev.owner = THIS_MODULE;
225 
226 	dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
227 	rmtfs_mem->dev.id = client_id;
228 	rmtfs_mem->dev.class = &rmtfs_class;
229 	rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
230 
231 	ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
232 	if (ret) {
233 		dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
234 		goto put_device;
235 	}
236 
237 	ret = of_property_read_u32(node, "qcom,vmid", &vmid);
238 	if (ret < 0 && ret != -EINVAL) {
239 		dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
240 		goto remove_cdev;
241 	} else if (!ret) {
242 		if (!qcom_scm_is_available()) {
243 			ret = -EPROBE_DEFER;
244 			goto remove_cdev;
245 		}
246 
247 		perms[0].vmid = QCOM_SCM_VMID_HLOS;
248 		perms[0].perm = QCOM_SCM_PERM_RW;
249 		perms[1].vmid = vmid;
250 		perms[1].perm = QCOM_SCM_PERM_RW;
251 
252 		rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
253 		ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
254 					  &rmtfs_mem->perms, perms, 2);
255 		if (ret < 0) {
256 			dev_err(&pdev->dev, "assign memory failed\n");
257 			goto remove_cdev;
258 		}
259 	}
260 
261 	dev_set_drvdata(&pdev->dev, rmtfs_mem);
262 
263 	return 0;
264 
265 remove_cdev:
266 	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
267 put_device:
268 	put_device(&rmtfs_mem->dev);
269 
270 	return ret;
271 }
272 
273 static int qcom_rmtfs_mem_remove(struct platform_device *pdev)
274 {
275 	struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
276 	struct qcom_scm_vmperm perm;
277 
278 	if (rmtfs_mem->perms) {
279 		perm.vmid = QCOM_SCM_VMID_HLOS;
280 		perm.perm = QCOM_SCM_PERM_RW;
281 
282 		qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
283 				    &rmtfs_mem->perms, &perm, 1);
284 	}
285 
286 	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
287 	put_device(&rmtfs_mem->dev);
288 
289 	return 0;
290 }
291 
292 static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
293 	{ .compatible = "qcom,rmtfs-mem" },
294 	{}
295 };
296 MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
297 
298 static struct platform_driver qcom_rmtfs_mem_driver = {
299 	.probe = qcom_rmtfs_mem_probe,
300 	.remove = qcom_rmtfs_mem_remove,
301 	.driver  = {
302 		.name  = "qcom_rmtfs_mem",
303 		.of_match_table = qcom_rmtfs_mem_of_match,
304 	},
305 };
306 
307 static int __init qcom_rmtfs_mem_init(void)
308 {
309 	int ret;
310 
311 	ret = class_register(&rmtfs_class);
312 	if (ret)
313 		return ret;
314 
315 	ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
316 				  QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
317 	if (ret < 0) {
318 		pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
319 		goto unregister_class;
320 	}
321 
322 	ret = platform_driver_register(&qcom_rmtfs_mem_driver);
323 	if (ret < 0) {
324 		pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
325 		goto unregister_chrdev;
326 	}
327 
328 	return 0;
329 
330 unregister_chrdev:
331 	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
332 unregister_class:
333 	class_unregister(&rmtfs_class);
334 	return ret;
335 }
336 module_init(qcom_rmtfs_mem_init);
337 
338 static void __exit qcom_rmtfs_mem_exit(void)
339 {
340 	platform_driver_unregister(&qcom_rmtfs_mem_driver);
341 	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
342 	class_unregister(&rmtfs_class);
343 }
344 module_exit(qcom_rmtfs_mem_exit);
345 
346 MODULE_AUTHOR("Linaro Ltd");
347 MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver");
348 MODULE_LICENSE("GPL v2");
349