2 * cros_ec_vbc - Expose the vboot context nvram to userspace
4 * Copyright (C) 2015 Collabora Ltd.
6 * based on vendor driver,
8 * Copyright (C) 2012 The Chromium OS Authors
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.
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.
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>
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)
31 struct device *dev = container_of(kobj, struct device, kobj);
32 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
33 struct cros_ec_device *ecdev = ec->ec_dev;
34 struct ec_params_vbnvcontext *params;
35 struct cros_ec_command *msg;
37 const size_t para_sz = sizeof(params->op);
38 const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
39 const size_t payload = max(para_sz, resp_sz);
41 msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
45 /* NB: we only kmalloc()ated enough space for the op field */
46 params = (struct ec_params_vbnvcontext *)msg->data;
47 params->op = EC_VBNV_CONTEXT_OP_READ;
49 msg->version = EC_VER_VBNV_CONTEXT;
50 msg->command = EC_CMD_VBNV_CONTEXT;
51 msg->outsize = para_sz;
52 msg->insize = resp_sz;
54 err = cros_ec_cmd_xfer(ecdev, msg);
56 dev_err(dev, "Error sending read request: %d\n", err);
61 memcpy(buf, msg->data, resp_sz);
67 static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
68 struct bin_attribute *attr, char *buf,
69 loff_t pos, size_t count)
71 struct device *dev = container_of(kobj, struct device, kobj);
72 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
73 struct cros_ec_device *ecdev = ec->ec_dev;
74 struct ec_params_vbnvcontext *params;
75 struct cros_ec_command *msg;
77 const size_t para_sz = sizeof(*params);
78 const size_t data_sz = sizeof(params->block);
80 /* Only write full values */
84 msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
88 params = (struct ec_params_vbnvcontext *)msg->data;
89 params->op = EC_VBNV_CONTEXT_OP_WRITE;
90 memcpy(params->block, buf, data_sz);
92 msg->version = EC_VER_VBNV_CONTEXT;
93 msg->command = EC_CMD_VBNV_CONTEXT;
94 msg->outsize = para_sz;
97 err = cros_ec_cmd_xfer(ecdev, msg);
99 dev_err(dev, "Error sending write request: %d\n", err);
108 static umode_t cros_ec_vbc_is_visible(struct kobject *kobj,
109 struct bin_attribute *a, int n)
111 struct device *dev = container_of(kobj, struct device, kobj);
112 struct cros_ec_dev *ec = to_cros_ec_dev(dev);
113 struct device_node *np = ec->ec_dev->dev->of_node;
115 if (IS_ENABLED(CONFIG_OF) && np) {
116 if (of_property_read_bool(np, "google,has-vbc-nvram"))
123 static BIN_ATTR_RW(vboot_context, 16);
125 static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
126 &bin_attr_vboot_context,
130 struct attribute_group cros_ec_vbc_attr_group = {
132 .bin_attrs = cros_ec_vbc_bin_attrs,
133 .is_bin_visible = cros_ec_vbc_is_visible,
135 EXPORT_SYMBOL(cros_ec_vbc_attr_group);