1 // SPDX-License-Identifier: GPL-2.0+
2 // Expose the vboot context nvram to userspace
4 // Copyright (C) 2012 Google, Inc.
5 // Copyright (C) 2015 Collabora Ltd.
8 #include <linux/platform_device.h>
9 #include <linux/mfd/cros_ec.h>
10 #include <linux/module.h>
11 #include <linux/platform_data/cros_ec_commands.h>
12 #include <linux/platform_data/cros_ec_proto.h>
13 #include <linux/slab.h>
15 #define DRV_NAME "cros-ec-vbc"
17 static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
18 struct bin_attribute *att, char *buf,
19 loff_t pos, size_t count)
21 struct device *dev = container_of(kobj, struct device, kobj);
22 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
23 struct cros_ec_device *ecdev = ec->ec_dev;
24 struct ec_params_vbnvcontext *params;
25 struct cros_ec_command *msg;
27 const size_t para_sz = sizeof(params->op);
28 const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
29 const size_t payload = max(para_sz, resp_sz);
31 msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
35 /* NB: we only kmalloc()ated enough space for the op field */
36 params = (struct ec_params_vbnvcontext *)msg->data;
37 params->op = EC_VBNV_CONTEXT_OP_READ;
39 msg->version = EC_VER_VBNV_CONTEXT;
40 msg->command = EC_CMD_VBNV_CONTEXT;
41 msg->outsize = para_sz;
42 msg->insize = resp_sz;
44 err = cros_ec_cmd_xfer(ecdev, msg);
46 dev_err(dev, "Error sending read request: %d\n", err);
51 memcpy(buf, msg->data, resp_sz);
57 static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
58 struct bin_attribute *attr, char *buf,
59 loff_t pos, size_t count)
61 struct device *dev = container_of(kobj, struct device, kobj);
62 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
63 struct cros_ec_device *ecdev = ec->ec_dev;
64 struct ec_params_vbnvcontext *params;
65 struct cros_ec_command *msg;
67 const size_t para_sz = sizeof(*params);
68 const size_t data_sz = sizeof(params->block);
70 /* Only write full values */
74 msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
78 params = (struct ec_params_vbnvcontext *)msg->data;
79 params->op = EC_VBNV_CONTEXT_OP_WRITE;
80 memcpy(params->block, buf, data_sz);
82 msg->version = EC_VER_VBNV_CONTEXT;
83 msg->command = EC_CMD_VBNV_CONTEXT;
84 msg->outsize = para_sz;
87 err = cros_ec_cmd_xfer(ecdev, msg);
89 dev_err(dev, "Error sending write request: %d\n", err);
98 static BIN_ATTR_RW(vboot_context, 16);
100 static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
101 &bin_attr_vboot_context,
105 static struct attribute_group cros_ec_vbc_attr_group = {
107 .bin_attrs = cros_ec_vbc_bin_attrs,
110 static int cros_ec_vbc_probe(struct platform_device *pd)
112 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
113 struct device *dev = &pd->dev;
116 ret = sysfs_create_group(&ec_dev->class_dev.kobj,
117 &cros_ec_vbc_attr_group);
119 dev_err(dev, "failed to create %s attributes. err=%d\n",
120 cros_ec_vbc_attr_group.name, ret);
125 static int cros_ec_vbc_remove(struct platform_device *pd)
127 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
129 sysfs_remove_group(&ec_dev->class_dev.kobj,
130 &cros_ec_vbc_attr_group);
135 static struct platform_driver cros_ec_vbc_driver = {
139 .probe = cros_ec_vbc_probe,
140 .remove = cros_ec_vbc_remove,
143 module_platform_driver(cros_ec_vbc_driver);
145 MODULE_LICENSE("GPL");
146 MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
147 MODULE_ALIAS("platform:" DRV_NAME);