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 cros_ec_command *msg; |
24 | /* |
25 | * This should be a pointer to the same type as op field in |
26 | * struct ec_params_vbnvcontext. |
27 | */ |
28 | uint32_t *params_op; |
29 | int err; |
30 | const size_t para_sz = sizeof(*params_op); |
31 | const size_t resp_sz = sizeof(struct ec_response_vbnvcontext); |
32 | const size_t payload = max(para_sz, resp_sz); |
33 | |
34 | msg = kmalloc(size: sizeof(*msg) + payload, GFP_KERNEL); |
35 | if (!msg) |
36 | return -ENOMEM; |
37 | |
38 | /* NB: we only kmalloc()ated enough space for the op field */ |
39 | params_op = (uint32_t *)msg->data; |
40 | *params_op = EC_VBNV_CONTEXT_OP_READ; |
41 | |
42 | msg->version = EC_VER_VBNV_CONTEXT; |
43 | msg->command = EC_CMD_VBNV_CONTEXT; |
44 | msg->outsize = para_sz; |
45 | msg->insize = resp_sz; |
46 | |
47 | err = cros_ec_cmd_xfer_status(ec_dev: ecdev, msg); |
48 | if (err < 0) { |
49 | dev_err(dev, "Error sending read request: %d\n" , err); |
50 | kfree(objp: msg); |
51 | return err; |
52 | } |
53 | |
54 | memcpy(buf, msg->data, resp_sz); |
55 | |
56 | kfree(objp: msg); |
57 | return resp_sz; |
58 | } |
59 | |
60 | static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj, |
61 | struct bin_attribute *attr, char *buf, |
62 | loff_t pos, size_t count) |
63 | { |
64 | struct device *dev = kobj_to_dev(kobj); |
65 | struct cros_ec_dev *ec = to_cros_ec_dev(dev); |
66 | struct cros_ec_device *ecdev = ec->ec_dev; |
67 | struct ec_params_vbnvcontext *params; |
68 | struct cros_ec_command *msg; |
69 | int err; |
70 | const size_t para_sz = sizeof(*params); |
71 | const size_t data_sz = sizeof(params->block); |
72 | |
73 | /* Only write full values */ |
74 | if (count != data_sz) |
75 | return -EINVAL; |
76 | |
77 | msg = kmalloc(size: sizeof(*msg) + para_sz, GFP_KERNEL); |
78 | if (!msg) |
79 | return -ENOMEM; |
80 | |
81 | params = (struct ec_params_vbnvcontext *)msg->data; |
82 | params->op = EC_VBNV_CONTEXT_OP_WRITE; |
83 | memcpy(params->block, buf, data_sz); |
84 | |
85 | msg->version = EC_VER_VBNV_CONTEXT; |
86 | msg->command = EC_CMD_VBNV_CONTEXT; |
87 | msg->outsize = para_sz; |
88 | msg->insize = 0; |
89 | |
90 | err = cros_ec_cmd_xfer_status(ec_dev: ecdev, msg); |
91 | if (err < 0) { |
92 | dev_err(dev, "Error sending write request: %d\n" , err); |
93 | kfree(objp: msg); |
94 | return err; |
95 | } |
96 | |
97 | kfree(objp: msg); |
98 | return data_sz; |
99 | } |
100 | |
101 | static BIN_ATTR_RW(vboot_context, 16); |
102 | |
103 | static struct bin_attribute *cros_ec_vbc_bin_attrs[] = { |
104 | &bin_attr_vboot_context, |
105 | NULL |
106 | }; |
107 | |
108 | static const struct attribute_group cros_ec_vbc_attr_group = { |
109 | .name = "vbc" , |
110 | .bin_attrs = cros_ec_vbc_bin_attrs, |
111 | }; |
112 | |
113 | static int cros_ec_vbc_probe(struct platform_device *pd) |
114 | { |
115 | struct cros_ec_dev *ec_dev = dev_get_drvdata(dev: pd->dev.parent); |
116 | struct device *dev = &pd->dev; |
117 | int ret; |
118 | |
119 | ret = sysfs_create_group(kobj: &ec_dev->class_dev.kobj, |
120 | grp: &cros_ec_vbc_attr_group); |
121 | if (ret < 0) |
122 | dev_err(dev, "failed to create %s attributes. err=%d\n" , |
123 | cros_ec_vbc_attr_group.name, ret); |
124 | |
125 | return ret; |
126 | } |
127 | |
128 | static void cros_ec_vbc_remove(struct platform_device *pd) |
129 | { |
130 | struct cros_ec_dev *ec_dev = dev_get_drvdata(dev: pd->dev.parent); |
131 | |
132 | sysfs_remove_group(kobj: &ec_dev->class_dev.kobj, |
133 | grp: &cros_ec_vbc_attr_group); |
134 | } |
135 | |
136 | static struct platform_driver cros_ec_vbc_driver = { |
137 | .driver = { |
138 | .name = DRV_NAME, |
139 | }, |
140 | .probe = cros_ec_vbc_probe, |
141 | .remove_new = cros_ec_vbc_remove, |
142 | }; |
143 | |
144 | module_platform_driver(cros_ec_vbc_driver); |
145 | |
146 | MODULE_LICENSE("GPL" ); |
147 | MODULE_DESCRIPTION("Expose the vboot context nvram to userspace" ); |
148 | MODULE_ALIAS("platform:" DRV_NAME); |
149 | |