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18800fc7 EL |
1 | /* |
2 | * cros_ec_vbc - Expose the vboot context nvram to userspace | |
3 | * | |
4 | * Copyright (C) 2015 Collabora Ltd. | |
5 | * | |
6 | * based on vendor driver, | |
7 | * | |
8 | * Copyright (C) 2012 The Chromium OS Authors | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | */ | |
20 | ||
21 | #include <linux/of.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/mfd/cros_ec.h> | |
24 | #include <linux/mfd/cros_ec_commands.h> | |
25 | #include <linux/slab.h> | |
26 | ||
27 | static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj, | |
28 | struct bin_attribute *att, char *buf, | |
29 | loff_t pos, size_t count) | |
30 | { | |
31 | struct device *dev = container_of(kobj, struct device, kobj); | |
32 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, | |
33 | class_dev); | |
34 | struct cros_ec_device *ecdev = ec->ec_dev; | |
35 | struct ec_params_vbnvcontext *params; | |
36 | struct cros_ec_command *msg; | |
37 | int err; | |
38 | const size_t para_sz = sizeof(params->op); | |
39 | const size_t resp_sz = sizeof(struct ec_response_vbnvcontext); | |
40 | const size_t payload = max(para_sz, resp_sz); | |
41 | ||
42 | msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL); | |
43 | if (!msg) | |
44 | return -ENOMEM; | |
45 | ||
46 | /* NB: we only kmalloc()ated enough space for the op field */ | |
47 | params = (struct ec_params_vbnvcontext *)msg->data; | |
48 | params->op = EC_VBNV_CONTEXT_OP_READ; | |
49 | ||
50 | msg->version = EC_VER_VBNV_CONTEXT; | |
51 | msg->command = EC_CMD_VBNV_CONTEXT; | |
52 | msg->outsize = para_sz; | |
53 | msg->insize = resp_sz; | |
54 | ||
55 | err = cros_ec_cmd_xfer(ecdev, msg); | |
56 | if (err < 0) { | |
57 | dev_err(dev, "Error sending read request: %d\n", err); | |
58 | kfree(msg); | |
59 | return err; | |
60 | } | |
61 | ||
62 | memcpy(buf, msg->data, resp_sz); | |
63 | ||
64 | kfree(msg); | |
65 | return resp_sz; | |
66 | } | |
67 | ||
68 | static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj, | |
69 | struct bin_attribute *attr, char *buf, | |
70 | loff_t pos, size_t count) | |
71 | { | |
72 | struct device *dev = container_of(kobj, struct device, kobj); | |
73 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, | |
74 | class_dev); | |
75 | struct cros_ec_device *ecdev = ec->ec_dev; | |
76 | struct ec_params_vbnvcontext *params; | |
77 | struct cros_ec_command *msg; | |
78 | int err; | |
79 | const size_t para_sz = sizeof(*params); | |
80 | const size_t data_sz = sizeof(params->block); | |
81 | ||
82 | /* Only write full values */ | |
83 | if (count != data_sz) | |
84 | return -EINVAL; | |
85 | ||
86 | msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL); | |
87 | if (!msg) | |
88 | return -ENOMEM; | |
89 | ||
90 | params = (struct ec_params_vbnvcontext *)msg->data; | |
91 | params->op = EC_VBNV_CONTEXT_OP_WRITE; | |
92 | memcpy(params->block, buf, data_sz); | |
93 | ||
94 | msg->version = EC_VER_VBNV_CONTEXT; | |
95 | msg->command = EC_CMD_VBNV_CONTEXT; | |
96 | msg->outsize = para_sz; | |
97 | msg->insize = 0; | |
98 | ||
99 | err = cros_ec_cmd_xfer(ecdev, msg); | |
100 | if (err < 0) { | |
101 | dev_err(dev, "Error sending write request: %d\n", err); | |
102 | kfree(msg); | |
103 | return err; | |
104 | } | |
105 | ||
106 | kfree(msg); | |
107 | return data_sz; | |
108 | } | |
109 | ||
110 | static umode_t cros_ec_vbc_is_visible(struct kobject *kobj, | |
111 | struct bin_attribute *a, int n) | |
112 | { | |
113 | struct device *dev = container_of(kobj, struct device, kobj); | |
114 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, | |
115 | class_dev); | |
116 | struct device_node *np = ec->ec_dev->dev->of_node; | |
117 | ||
118 | if (IS_ENABLED(CONFIG_OF) && np) { | |
119 | if (of_property_read_bool(np, "google,has-vbc-nvram")) | |
120 | return a->attr.mode; | |
121 | } | |
122 | ||
123 | return 0; | |
124 | } | |
125 | ||
126 | static BIN_ATTR_RW(vboot_context, 16); | |
127 | ||
128 | static struct bin_attribute *cros_ec_vbc_bin_attrs[] = { | |
129 | &bin_attr_vboot_context, | |
130 | NULL | |
131 | }; | |
132 | ||
133 | struct attribute_group cros_ec_vbc_attr_group = { | |
134 | .name = "vbc", | |
135 | .bin_attrs = cros_ec_vbc_bin_attrs, | |
136 | .is_bin_visible = cros_ec_vbc_is_visible, | |
137 | }; |