1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | // Expose the vboot context nvram to userspace |
3 | // |
4 | // Copyright (C) 2012 Google, Inc. |
5 | // Copyright (C) 2015 Collabora Ltd. |
6 | |
7 | #include <linux/of.h> |
8 | #include <linux/platform_device.h> |
9 | #include <linux/module.h> |
10 | #include <linux/platform_data/cros_ec_commands.h> |
11 | #include <linux/platform_data/cros_ec_proto.h> |
12 | #include <linux/slab.h> |
13 | |
14 | #define DRV_NAME "cros-ec-vbc" |
15 | |
16 | static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj, |
17 | struct bin_attribute *att, char *buf, |
18 | loff_t pos, size_t count) |
19 | { |
20 | struct device *dev = kobj_to_dev(kobj); |
21 | struct cros_ec_dev *ec = to_cros_ec_dev(dev); |
22 | struct cros_ec_device *ecdev = ec->ec_dev; |
23 | struct ec_params_vbnvcontext *params; |
24 | struct cros_ec_command *msg; |
25 | int err; |
26 | const size_t para_sz = sizeof(params->op); |
27 | const size_t resp_sz = sizeof(struct ec_response_vbnvcontext); |
28 | const size_t payload = max(para_sz, resp_sz); |
29 | |
30 | msg = kmalloc(size: sizeof(*msg) + payload, GFP_KERNEL); |
31 | if (!msg) |
32 | return -ENOMEM; |
33 | |
34 | /* NB: we only kmalloc()ated enough space for the op field */ |
35 | params = (struct ec_params_vbnvcontext *)msg->data; |
36 | params->op = EC_VBNV_CONTEXT_OP_READ; |
37 | |
38 | msg->version = EC_VER_VBNV_CONTEXT; |
39 | msg->command = EC_CMD_VBNV_CONTEXT; |
40 | msg->outsize = para_sz; |
41 | msg->insize = resp_sz; |
42 | |
43 | err = cros_ec_cmd_xfer_status(ec_dev: ecdev, msg); |
44 | if (err < 0) { |
45 | dev_err(dev, "Error sending read request: %d\n" , err); |
46 | kfree(objp: msg); |
47 | return err; |
48 | } |
49 | |
50 | memcpy(buf, msg->data, resp_sz); |
51 | |
52 | kfree(objp: msg); |
53 | return resp_sz; |
54 | } |
55 | |
56 | static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj, |
57 | struct bin_attribute *attr, char *buf, |
58 | loff_t pos, size_t count) |
59 | { |
60 | struct device *dev = kobj_to_dev(kobj); |
61 | struct cros_ec_dev *ec = to_cros_ec_dev(dev); |
62 | struct cros_ec_device *ecdev = ec->ec_dev; |
63 | struct ec_params_vbnvcontext *params; |
64 | struct cros_ec_command *msg; |
65 | int err; |
66 | const size_t para_sz = sizeof(*params); |
67 | const size_t data_sz = sizeof(params->block); |
68 | |
69 | /* Only write full values */ |
70 | if (count != data_sz) |
71 | return -EINVAL; |
72 | |
73 | msg = kmalloc(size: sizeof(*msg) + para_sz, GFP_KERNEL); |
74 | if (!msg) |
75 | return -ENOMEM; |
76 | |
77 | params = (struct ec_params_vbnvcontext *)msg->data; |
78 | params->op = EC_VBNV_CONTEXT_OP_WRITE; |
79 | memcpy(params->block, buf, data_sz); |
80 | |
81 | msg->version = EC_VER_VBNV_CONTEXT; |
82 | msg->command = EC_CMD_VBNV_CONTEXT; |
83 | msg->outsize = para_sz; |
84 | msg->insize = 0; |
85 | |
86 | err = cros_ec_cmd_xfer_status(ec_dev: ecdev, msg); |
87 | if (err < 0) { |
88 | dev_err(dev, "Error sending write request: %d\n" , err); |
89 | kfree(objp: msg); |
90 | return err; |
91 | } |
92 | |
93 | kfree(objp: msg); |
94 | return data_sz; |
95 | } |
96 | |
97 | static BIN_ATTR_RW(vboot_context, 16); |
98 | |
99 | static struct bin_attribute *cros_ec_vbc_bin_attrs[] = { |
100 | &bin_attr_vboot_context, |
101 | NULL |
102 | }; |
103 | |
104 | static const struct attribute_group cros_ec_vbc_attr_group = { |
105 | .name = "vbc" , |
106 | .bin_attrs = cros_ec_vbc_bin_attrs, |
107 | }; |
108 | |
109 | static int cros_ec_vbc_probe(struct platform_device *pd) |
110 | { |
111 | struct cros_ec_dev *ec_dev = dev_get_drvdata(dev: pd->dev.parent); |
112 | struct device *dev = &pd->dev; |
113 | int ret; |
114 | |
115 | ret = sysfs_create_group(kobj: &ec_dev->class_dev.kobj, |
116 | grp: &cros_ec_vbc_attr_group); |
117 | if (ret < 0) |
118 | dev_err(dev, "failed to create %s attributes. err=%d\n" , |
119 | cros_ec_vbc_attr_group.name, ret); |
120 | |
121 | return ret; |
122 | } |
123 | |
124 | static void cros_ec_vbc_remove(struct platform_device *pd) |
125 | { |
126 | struct cros_ec_dev *ec_dev = dev_get_drvdata(dev: pd->dev.parent); |
127 | |
128 | sysfs_remove_group(kobj: &ec_dev->class_dev.kobj, |
129 | grp: &cros_ec_vbc_attr_group); |
130 | } |
131 | |
132 | static struct platform_driver cros_ec_vbc_driver = { |
133 | .driver = { |
134 | .name = DRV_NAME, |
135 | }, |
136 | .probe = cros_ec_vbc_probe, |
137 | .remove_new = cros_ec_vbc_remove, |
138 | }; |
139 | |
140 | module_platform_driver(cros_ec_vbc_driver); |
141 | |
142 | MODULE_LICENSE("GPL" ); |
143 | MODULE_DESCRIPTION("Expose the vboot context nvram to userspace" ); |
144 | MODULE_ALIAS("platform:" DRV_NAME); |
145 | |