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/qcom_scm.h>
18
19#define QCOM_RMTFS_MEM_DEV_MAX	(MINORMASK + 1)
20
21static dev_t qcom_rmtfs_mem_major;
22
23struct qcom_rmtfs_mem {
24	struct device dev;
25	struct cdev cdev;
26
27	void *base;
28	phys_addr_t addr;
29	phys_addr_t size;
30
31	unsigned int client_id;
32
33	unsigned int perms;
34};
35
36static ssize_t qcom_rmtfs_mem_show(struct device *dev,
37			      struct device_attribute *attr,
38			      char *buf);
39
40static DEVICE_ATTR(phys_addr, 0444, qcom_rmtfs_mem_show, NULL);
41static DEVICE_ATTR(size, 0444, qcom_rmtfs_mem_show, NULL);
42static DEVICE_ATTR(client_id, 0444, qcom_rmtfs_mem_show, NULL);
43
44static ssize_t qcom_rmtfs_mem_show(struct device *dev,
45			      struct device_attribute *attr,
46			      char *buf)
47{
48	struct qcom_rmtfs_mem *rmtfs_mem = container_of(dev,
49							struct qcom_rmtfs_mem,
50							dev);
51
52	if (attr == &dev_attr_phys_addr)
53		return sprintf(buf, "%pa\n", &rmtfs_mem->addr);
54	if (attr == &dev_attr_size)
55		return sprintf(buf, "%pa\n", &rmtfs_mem->size);
56	if (attr == &dev_attr_client_id)
57		return sprintf(buf, "%d\n", rmtfs_mem->client_id);
58
59	return -EINVAL;
60}
61
62static struct attribute *qcom_rmtfs_mem_attrs[] = {
63	&dev_attr_phys_addr.attr,
64	&dev_attr_size.attr,
65	&dev_attr_client_id.attr,
66	NULL
67};
68ATTRIBUTE_GROUPS(qcom_rmtfs_mem);
69
70static int qcom_rmtfs_mem_open(struct inode *inode, struct file *filp)
71{
72	struct qcom_rmtfs_mem *rmtfs_mem = container_of(inode->i_cdev,
73							struct qcom_rmtfs_mem,
74							cdev);
75
76	get_device(&rmtfs_mem->dev);
77	filp->private_data = rmtfs_mem;
78
79	return 0;
80}
81static ssize_t qcom_rmtfs_mem_read(struct file *filp,
82			      char __user *buf, size_t count, loff_t *f_pos)
83{
84	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
85
86	if (*f_pos >= rmtfs_mem->size)
87		return 0;
88
89	if (*f_pos + count >= rmtfs_mem->size)
90		count = rmtfs_mem->size - *f_pos;
91
92	if (copy_to_user(buf, rmtfs_mem->base + *f_pos, count))
93		return -EFAULT;
94
95	*f_pos += count;
96	return count;
97}
98
99static ssize_t qcom_rmtfs_mem_write(struct file *filp,
100			       const char __user *buf, size_t count,
101			       loff_t *f_pos)
102{
103	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
104
105	if (*f_pos >= rmtfs_mem->size)
106		return 0;
107
108	if (*f_pos + count >= rmtfs_mem->size)
109		count = rmtfs_mem->size - *f_pos;
110
111	if (copy_from_user(rmtfs_mem->base + *f_pos, buf, count))
112		return -EFAULT;
113
114	*f_pos += count;
115	return count;
116}
117
118static int qcom_rmtfs_mem_release(struct inode *inode, struct file *filp)
119{
120	struct qcom_rmtfs_mem *rmtfs_mem = filp->private_data;
121
122	put_device(&rmtfs_mem->dev);
123
124	return 0;
125}
126
127static struct class rmtfs_class = {
128	.owner          = THIS_MODULE,
129	.name           = "rmtfs",
130};
131
132static 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
152static 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
162static 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
171static 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[2];
175	struct reserved_mem *rmem;
176	struct qcom_rmtfs_mem *rmtfs_mem;
177	u32 client_id;
178	u32 vmid;
179	int ret;
180
181	rmem = of_reserved_mem_lookup(node);
182	if (!rmem) {
183		dev_err(&pdev->dev, "failed to acquire memory region\n");
184		return -EINVAL;
185	}
186
187	ret = of_property_read_u32(node, "qcom,client-id", &client_id);
188	if (ret) {
189		dev_err(&pdev->dev, "failed to parse \"qcom,client-id\"\n");
190		return ret;
191
192	}
193
194	rmtfs_mem = kzalloc(sizeof(*rmtfs_mem), GFP_KERNEL);
195	if (!rmtfs_mem)
196		return -ENOMEM;
197
198	rmtfs_mem->addr = rmem->base;
199	rmtfs_mem->client_id = client_id;
200	rmtfs_mem->size = rmem->size;
201
202	device_initialize(&rmtfs_mem->dev);
203	rmtfs_mem->dev.parent = &pdev->dev;
204	rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
205	rmtfs_mem->dev.release = qcom_rmtfs_mem_release_device;
206
207	rmtfs_mem->base = devm_memremap(&rmtfs_mem->dev, rmtfs_mem->addr,
208					rmtfs_mem->size, MEMREMAP_WC);
209	if (IS_ERR(rmtfs_mem->base)) {
210		dev_err(&pdev->dev, "failed to remap rmtfs_mem region\n");
211		ret = PTR_ERR(rmtfs_mem->base);
212		goto put_device;
213	}
214
215	cdev_init(&rmtfs_mem->cdev, &qcom_rmtfs_mem_fops);
216	rmtfs_mem->cdev.owner = THIS_MODULE;
217
218	dev_set_name(&rmtfs_mem->dev, "qcom_rmtfs_mem%d", client_id);
219	rmtfs_mem->dev.id = client_id;
220	rmtfs_mem->dev.class = &rmtfs_class;
221	rmtfs_mem->dev.devt = MKDEV(MAJOR(qcom_rmtfs_mem_major), client_id);
222
223	ret = cdev_device_add(&rmtfs_mem->cdev, &rmtfs_mem->dev);
224	if (ret) {
225		dev_err(&pdev->dev, "failed to add cdev: %d\n", ret);
226		goto put_device;
227	}
228
229	ret = of_property_read_u32(node, "qcom,vmid", &vmid);
230	if (ret < 0 && ret != -EINVAL) {
231		dev_err(&pdev->dev, "failed to parse qcom,vmid\n");
232		goto remove_cdev;
233	} else if (!ret) {
234		if (!qcom_scm_is_available()) {
235			ret = -EPROBE_DEFER;
236			goto remove_cdev;
237		}
238
239		perms[0].vmid = QCOM_SCM_VMID_HLOS;
240		perms[0].perm = QCOM_SCM_PERM_RW;
241		perms[1].vmid = vmid;
242		perms[1].perm = QCOM_SCM_PERM_RW;
243
244		rmtfs_mem->perms = BIT(QCOM_SCM_VMID_HLOS);
245		ret = qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
246					  &rmtfs_mem->perms, perms, 2);
247		if (ret < 0) {
248			dev_err(&pdev->dev, "assign memory failed\n");
249			goto remove_cdev;
250		}
251	}
252
253	dev_set_drvdata(&pdev->dev, rmtfs_mem);
254
255	return 0;
256
257remove_cdev:
258	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
259put_device:
260	put_device(&rmtfs_mem->dev);
261
262	return ret;
263}
264
265static int qcom_rmtfs_mem_remove(struct platform_device *pdev)
266{
267	struct qcom_rmtfs_mem *rmtfs_mem = dev_get_drvdata(&pdev->dev);
268	struct qcom_scm_vmperm perm;
269
270	if (rmtfs_mem->perms) {
271		perm.vmid = QCOM_SCM_VMID_HLOS;
272		perm.perm = QCOM_SCM_PERM_RW;
273
274		qcom_scm_assign_mem(rmtfs_mem->addr, rmtfs_mem->size,
275				    &rmtfs_mem->perms, &perm, 1);
276	}
277
278	cdev_device_del(&rmtfs_mem->cdev, &rmtfs_mem->dev);
279	put_device(&rmtfs_mem->dev);
280
281	return 0;
282}
283
284static const struct of_device_id qcom_rmtfs_mem_of_match[] = {
285	{ .compatible = "qcom,rmtfs-mem" },
286	{}
287};
288MODULE_DEVICE_TABLE(of, qcom_rmtfs_mem_of_match);
289
290static struct platform_driver qcom_rmtfs_mem_driver = {
291	.probe = qcom_rmtfs_mem_probe,
292	.remove = qcom_rmtfs_mem_remove,
293	.driver  = {
294		.name  = "qcom_rmtfs_mem",
295		.of_match_table = qcom_rmtfs_mem_of_match,
296	},
297};
298
299static int __init qcom_rmtfs_mem_init(void)
300{
301	int ret;
302
303	ret = class_register(&rmtfs_class);
304	if (ret)
305		return ret;
306
307	ret = alloc_chrdev_region(&qcom_rmtfs_mem_major, 0,
308				  QCOM_RMTFS_MEM_DEV_MAX, "qcom_rmtfs_mem");
309	if (ret < 0) {
310		pr_err("qcom_rmtfs_mem: failed to allocate char dev region\n");
311		goto unregister_class;
312	}
313
314	ret = platform_driver_register(&qcom_rmtfs_mem_driver);
315	if (ret < 0) {
316		pr_err("qcom_rmtfs_mem: failed to register rmtfs_mem driver\n");
317		goto unregister_chrdev;
318	}
319
320	return 0;
321
322unregister_chrdev:
323	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
324unregister_class:
325	class_unregister(&rmtfs_class);
326	return ret;
327}
328module_init(qcom_rmtfs_mem_init);
329
330static void __exit qcom_rmtfs_mem_exit(void)
331{
332	platform_driver_unregister(&qcom_rmtfs_mem_driver);
333	unregister_chrdev_region(qcom_rmtfs_mem_major, QCOM_RMTFS_MEM_DEV_MAX);
334	class_unregister(&rmtfs_class);
335}
336module_exit(qcom_rmtfs_mem_exit);
337
338MODULE_AUTHOR("Linaro Ltd");
339MODULE_DESCRIPTION("Qualcomm Remote Filesystem memory driver");
340MODULE_LICENSE("GPL v2");
341