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/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>
14 #define DRV_NAME "cros-ec-vbc"
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)
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;
25 * This should be a pointer to the same type as op field in
26 * struct ec_params_vbnvcontext.
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);
34 msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
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;
42 msg->version = EC_VER_VBNV_CONTEXT;
43 msg->command = EC_CMD_VBNV_CONTEXT;
44 msg->outsize = para_sz;
45 msg->insize = resp_sz;
47 err = cros_ec_cmd_xfer_status(ecdev, msg);
49 dev_err(dev, "Error sending read request: %d\n", err);
54 memcpy(buf, msg->data, resp_sz);
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)
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;
70 const size_t para_sz = sizeof(*params);
71 const size_t data_sz = sizeof(params->block);
73 /* Only write full values */
77 msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
81 params = (struct ec_params_vbnvcontext *)msg->data;
82 params->op = EC_VBNV_CONTEXT_OP_WRITE;
83 memcpy(params->block, buf, data_sz);
85 msg->version = EC_VER_VBNV_CONTEXT;
86 msg->command = EC_CMD_VBNV_CONTEXT;
87 msg->outsize = para_sz;
90 err = cros_ec_cmd_xfer_status(ecdev, msg);
92 dev_err(dev, "Error sending write request: %d\n", err);
101 static BIN_ATTR_RW(vboot_context, 16);
103 static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
104 &bin_attr_vboot_context,
108 static const struct attribute_group cros_ec_vbc_attr_group = {
110 .bin_attrs = cros_ec_vbc_bin_attrs,
113 static int cros_ec_vbc_probe(struct platform_device *pd)
115 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
116 struct device *dev = &pd->dev;
119 ret = sysfs_create_group(&ec_dev->class_dev.kobj,
120 &cros_ec_vbc_attr_group);
122 dev_err(dev, "failed to create %s attributes. err=%d\n",
123 cros_ec_vbc_attr_group.name, ret);
128 static void cros_ec_vbc_remove(struct platform_device *pd)
130 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
132 sysfs_remove_group(&ec_dev->class_dev.kobj,
133 &cros_ec_vbc_attr_group);
136 static struct platform_driver cros_ec_vbc_driver = {
140 .probe = cros_ec_vbc_probe,
141 .remove_new = cros_ec_vbc_remove,
144 module_platform_driver(cros_ec_vbc_driver);
146 MODULE_LICENSE("GPL");
147 MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
148 MODULE_ALIAS("platform:" DRV_NAME);