Emilio López | 18800fc | 2015-09-21 10:38:22 -0300 | [diff] [blame] | 1 | /* |
| 2 | * cros_ec_vbc - Expose the vboot context nvram to userspace |
| 3 | * |
| 4 | * Copyright (C) 2015 Collabora Ltd. |
| 5 | * |
| 6 | * based on vendor driver, |
| 7 | * |
| 8 | * Copyright (C) 2012 The Chromium OS Authors |
| 9 | * |
| 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. |
| 14 | * |
| 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. |
| 19 | */ |
| 20 | |
| 21 | #include <linux/of.h> |
| 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> |
| 26 | |
| 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) |
| 30 | { |
| 31 | struct device *dev = container_of(kobj, struct device, kobj); |
| 32 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, |
| 33 | class_dev); |
| 34 | struct cros_ec_device *ecdev = ec->ec_dev; |
| 35 | struct ec_params_vbnvcontext *params; |
| 36 | struct cros_ec_command *msg; |
| 37 | int err; |
| 38 | const size_t para_sz = sizeof(params->op); |
| 39 | const size_t resp_sz = sizeof(struct ec_response_vbnvcontext); |
| 40 | const size_t payload = max(para_sz, resp_sz); |
| 41 | |
| 42 | msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL); |
| 43 | if (!msg) |
| 44 | return -ENOMEM; |
| 45 | |
| 46 | /* NB: we only kmalloc()ated enough space for the op field */ |
| 47 | params = (struct ec_params_vbnvcontext *)msg->data; |
| 48 | params->op = EC_VBNV_CONTEXT_OP_READ; |
| 49 | |
| 50 | msg->version = EC_VER_VBNV_CONTEXT; |
| 51 | msg->command = EC_CMD_VBNV_CONTEXT; |
| 52 | msg->outsize = para_sz; |
| 53 | msg->insize = resp_sz; |
| 54 | |
| 55 | err = cros_ec_cmd_xfer(ecdev, msg); |
| 56 | if (err < 0) { |
| 57 | dev_err(dev, "Error sending read request: %d\n", err); |
| 58 | kfree(msg); |
| 59 | return err; |
| 60 | } |
| 61 | |
| 62 | memcpy(buf, msg->data, resp_sz); |
| 63 | |
| 64 | kfree(msg); |
| 65 | return resp_sz; |
| 66 | } |
| 67 | |
| 68 | static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj, |
| 69 | struct bin_attribute *attr, char *buf, |
| 70 | loff_t pos, size_t count) |
| 71 | { |
| 72 | struct device *dev = container_of(kobj, struct device, kobj); |
| 73 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, |
| 74 | class_dev); |
| 75 | struct cros_ec_device *ecdev = ec->ec_dev; |
| 76 | struct ec_params_vbnvcontext *params; |
| 77 | struct cros_ec_command *msg; |
| 78 | int err; |
| 79 | const size_t para_sz = sizeof(*params); |
| 80 | const size_t data_sz = sizeof(params->block); |
| 81 | |
| 82 | /* Only write full values */ |
| 83 | if (count != data_sz) |
| 84 | return -EINVAL; |
| 85 | |
| 86 | msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL); |
| 87 | if (!msg) |
| 88 | return -ENOMEM; |
| 89 | |
| 90 | params = (struct ec_params_vbnvcontext *)msg->data; |
| 91 | params->op = EC_VBNV_CONTEXT_OP_WRITE; |
| 92 | memcpy(params->block, buf, data_sz); |
| 93 | |
| 94 | msg->version = EC_VER_VBNV_CONTEXT; |
| 95 | msg->command = EC_CMD_VBNV_CONTEXT; |
| 96 | msg->outsize = para_sz; |
| 97 | msg->insize = 0; |
| 98 | |
| 99 | err = cros_ec_cmd_xfer(ecdev, msg); |
| 100 | if (err < 0) { |
| 101 | dev_err(dev, "Error sending write request: %d\n", err); |
| 102 | kfree(msg); |
| 103 | return err; |
| 104 | } |
| 105 | |
| 106 | kfree(msg); |
| 107 | return data_sz; |
| 108 | } |
| 109 | |
| 110 | static umode_t cros_ec_vbc_is_visible(struct kobject *kobj, |
| 111 | struct bin_attribute *a, int n) |
| 112 | { |
| 113 | struct device *dev = container_of(kobj, struct device, kobj); |
| 114 | struct cros_ec_dev *ec = container_of(dev, struct cros_ec_dev, |
| 115 | class_dev); |
| 116 | struct device_node *np = ec->ec_dev->dev->of_node; |
| 117 | |
| 118 | if (IS_ENABLED(CONFIG_OF) && np) { |
| 119 | if (of_property_read_bool(np, "google,has-vbc-nvram")) |
| 120 | return a->attr.mode; |
| 121 | } |
| 122 | |
| 123 | return 0; |
| 124 | } |
| 125 | |
| 126 | static BIN_ATTR_RW(vboot_context, 16); |
| 127 | |
| 128 | static struct bin_attribute *cros_ec_vbc_bin_attrs[] = { |
| 129 | &bin_attr_vboot_context, |
| 130 | NULL |
| 131 | }; |
| 132 | |
| 133 | struct attribute_group cros_ec_vbc_attr_group = { |
| 134 | .name = "vbc", |
| 135 | .bin_attrs = cros_ec_vbc_bin_attrs, |
| 136 | .is_bin_visible = cros_ec_vbc_is_visible, |
| 137 | }; |