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680ca6dc CB |
1 | /* |
2 | * SCOM FSI Client device driver | |
3 | * | |
4 | * Copyright (C) IBM Corporation 2016 | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERGCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/fsi.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/cdev.h> | |
19 | #include <linux/delay.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/uaccess.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/miscdevice.h> | |
24 | #include <linux/list.h> | |
25 | #include <linux/idr.h> | |
26 | ||
27 | #define FSI_ENGID_SCOM 0x5 | |
28 | ||
29 | #define SCOM_FSI2PIB_DELAY 50 | |
30 | ||
31 | /* SCOM engine register set */ | |
32 | #define SCOM_DATA0_REG 0x00 | |
33 | #define SCOM_DATA1_REG 0x04 | |
34 | #define SCOM_CMD_REG 0x08 | |
35 | #define SCOM_RESET_REG 0x1C | |
36 | ||
37 | #define SCOM_RESET_CMD 0x80000000 | |
38 | #define SCOM_WRITE_CMD 0x80000000 | |
39 | ||
40 | struct scom_device { | |
41 | struct list_head link; | |
42 | struct fsi_device *fsi_dev; | |
43 | struct miscdevice mdev; | |
44 | char name[32]; | |
45 | int idx; | |
46 | }; | |
47 | ||
48 | #define to_scom_dev(x) container_of((x), struct scom_device, mdev) | |
49 | ||
50 | static struct list_head scom_devices; | |
51 | ||
52 | static DEFINE_IDA(scom_ida); | |
53 | ||
54 | static int put_scom(struct scom_device *scom_dev, uint64_t value, | |
55 | uint32_t addr) | |
56 | { | |
57 | int rc; | |
58 | uint32_t data; | |
59 | ||
680ca6dc CB |
60 | data = cpu_to_be32((value >> 32) & 0xffffffff); |
61 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA0_REG, &data, | |
62 | sizeof(uint32_t)); | |
63 | if (rc) | |
64 | return rc; | |
65 | ||
66 | data = cpu_to_be32(value & 0xffffffff); | |
67 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_DATA1_REG, &data, | |
68 | sizeof(uint32_t)); | |
69 | if (rc) | |
70 | return rc; | |
71 | ||
72 | data = cpu_to_be32(SCOM_WRITE_CMD | addr); | |
73 | return fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, | |
74 | sizeof(uint32_t)); | |
75 | } | |
76 | ||
77 | static int get_scom(struct scom_device *scom_dev, uint64_t *value, | |
78 | uint32_t addr) | |
79 | { | |
80 | uint32_t result, data; | |
81 | int rc; | |
82 | ||
83 | *value = 0ULL; | |
84 | data = cpu_to_be32(addr); | |
85 | rc = fsi_device_write(scom_dev->fsi_dev, SCOM_CMD_REG, &data, | |
86 | sizeof(uint32_t)); | |
87 | if (rc) | |
88 | return rc; | |
89 | ||
90 | rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA0_REG, &result, | |
91 | sizeof(uint32_t)); | |
92 | if (rc) | |
93 | return rc; | |
94 | ||
95 | *value |= (uint64_t)cpu_to_be32(result) << 32; | |
96 | rc = fsi_device_read(scom_dev->fsi_dev, SCOM_DATA1_REG, &result, | |
97 | sizeof(uint32_t)); | |
98 | if (rc) | |
99 | return rc; | |
100 | ||
101 | *value |= cpu_to_be32(result); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | static ssize_t scom_read(struct file *filep, char __user *buf, size_t len, | |
107 | loff_t *offset) | |
108 | { | |
109 | int rc; | |
110 | struct miscdevice *mdev = | |
111 | (struct miscdevice *)filep->private_data; | |
112 | struct scom_device *scom = to_scom_dev(mdev); | |
113 | struct device *dev = &scom->fsi_dev->dev; | |
114 | uint64_t val; | |
115 | ||
116 | if (len != sizeof(uint64_t)) | |
117 | return -EINVAL; | |
118 | ||
119 | rc = get_scom(scom, &val, *offset); | |
120 | if (rc) { | |
121 | dev_dbg(dev, "get_scom fail:%d\n", rc); | |
122 | return rc; | |
123 | } | |
124 | ||
125 | rc = copy_to_user(buf, &val, len); | |
126 | if (rc) | |
127 | dev_dbg(dev, "copy to user failed:%d\n", rc); | |
128 | ||
129 | return rc ? rc : len; | |
130 | } | |
131 | ||
132 | static ssize_t scom_write(struct file *filep, const char __user *buf, | |
133 | size_t len, loff_t *offset) | |
134 | { | |
135 | int rc; | |
136 | struct miscdevice *mdev = filep->private_data; | |
137 | struct scom_device *scom = to_scom_dev(mdev); | |
138 | struct device *dev = &scom->fsi_dev->dev; | |
139 | uint64_t val; | |
140 | ||
141 | if (len != sizeof(uint64_t)) | |
142 | return -EINVAL; | |
143 | ||
144 | rc = copy_from_user(&val, buf, len); | |
145 | if (rc) { | |
146 | dev_dbg(dev, "copy from user failed:%d\n", rc); | |
147 | return -EINVAL; | |
148 | } | |
149 | ||
150 | rc = put_scom(scom, val, *offset); | |
151 | if (rc) { | |
152 | dev_dbg(dev, "put_scom failed with:%d\n", rc); | |
153 | return rc; | |
154 | } | |
155 | ||
156 | return len; | |
157 | } | |
158 | ||
159 | static loff_t scom_llseek(struct file *file, loff_t offset, int whence) | |
160 | { | |
161 | switch (whence) { | |
162 | case SEEK_CUR: | |
163 | break; | |
164 | case SEEK_SET: | |
165 | file->f_pos = offset; | |
166 | break; | |
167 | default: | |
168 | return -EINVAL; | |
169 | } | |
170 | ||
171 | return offset; | |
172 | } | |
173 | ||
174 | static const struct file_operations scom_fops = { | |
175 | .owner = THIS_MODULE, | |
176 | .llseek = scom_llseek, | |
177 | .read = scom_read, | |
178 | .write = scom_write, | |
179 | }; | |
180 | ||
181 | static int scom_probe(struct device *dev) | |
182 | { | |
47a6623b | 183 | uint32_t data; |
680ca6dc CB |
184 | struct fsi_device *fsi_dev = to_fsi_dev(dev); |
185 | struct scom_device *scom; | |
186 | ||
187 | scom = devm_kzalloc(dev, sizeof(*scom), GFP_KERNEL); | |
188 | if (!scom) | |
189 | return -ENOMEM; | |
190 | ||
191 | scom->idx = ida_simple_get(&scom_ida, 1, INT_MAX, GFP_KERNEL); | |
192 | snprintf(scom->name, sizeof(scom->name), "scom%d", scom->idx); | |
193 | scom->fsi_dev = fsi_dev; | |
194 | scom->mdev.minor = MISC_DYNAMIC_MINOR; | |
195 | scom->mdev.fops = &scom_fops; | |
196 | scom->mdev.name = scom->name; | |
197 | scom->mdev.parent = dev; | |
198 | list_add(&scom->link, &scom_devices); | |
199 | ||
47a6623b EJ |
200 | data = cpu_to_be32(SCOM_RESET_CMD); |
201 | fsi_device_write(fsi_dev, SCOM_RESET_REG, &data, sizeof(uint32_t)); | |
202 | ||
680ca6dc CB |
203 | return misc_register(&scom->mdev); |
204 | } | |
205 | ||
206 | static int scom_remove(struct device *dev) | |
207 | { | |
208 | struct scom_device *scom, *scom_tmp; | |
209 | struct fsi_device *fsi_dev = to_fsi_dev(dev); | |
210 | ||
211 | list_for_each_entry_safe(scom, scom_tmp, &scom_devices, link) { | |
212 | if (scom->fsi_dev == fsi_dev) { | |
213 | list_del(&scom->link); | |
214 | ida_simple_remove(&scom_ida, scom->idx); | |
215 | misc_deregister(&scom->mdev); | |
216 | } | |
217 | } | |
218 | ||
219 | return 0; | |
220 | } | |
221 | ||
222 | static struct fsi_device_id scom_ids[] = { | |
223 | { | |
224 | .engine_type = FSI_ENGID_SCOM, | |
225 | .version = FSI_VERSION_ANY, | |
226 | }, | |
227 | { 0 } | |
228 | }; | |
229 | ||
230 | static struct fsi_driver scom_drv = { | |
231 | .id_table = scom_ids, | |
232 | .drv = { | |
233 | .name = "scom", | |
234 | .bus = &fsi_bus_type, | |
235 | .probe = scom_probe, | |
236 | .remove = scom_remove, | |
237 | } | |
238 | }; | |
239 | ||
240 | static int scom_init(void) | |
241 | { | |
242 | INIT_LIST_HEAD(&scom_devices); | |
243 | return fsi_driver_register(&scom_drv); | |
244 | } | |
245 | ||
246 | static void scom_exit(void) | |
247 | { | |
248 | struct list_head *pos; | |
249 | struct scom_device *scom; | |
250 | ||
251 | list_for_each(pos, &scom_devices) { | |
252 | scom = list_entry(pos, struct scom_device, link); | |
253 | misc_deregister(&scom->mdev); | |
254 | devm_kfree(&scom->fsi_dev->dev, scom); | |
255 | } | |
256 | fsi_driver_unregister(&scom_drv); | |
257 | } | |
258 | ||
259 | module_init(scom_init); | |
260 | module_exit(scom_exit); | |
261 | MODULE_LICENSE("GPL"); |