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1// SPDX-License-Identifier: GPL-2.0+2// Expose the vboot context nvram to userspace3//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/mod_devicetable.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>14 15#define DRV_NAME "cros-ec-vbc"16 17static 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)20{21 struct device *dev = kobj_to_dev(kobj);22 struct cros_ec_dev *ec = to_cros_ec_dev(dev);23 struct cros_ec_device *ecdev = ec->ec_dev;24 struct cros_ec_command *msg;25 /*26 * This should be a pointer to the same type as op field in27 * struct ec_params_vbnvcontext.28 */29 uint32_t *params_op;30 int err;31 const size_t para_sz = sizeof(*params_op);32 const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);33 const size_t payload = max(para_sz, resp_sz);34 35 msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);36 if (!msg)37 return -ENOMEM;38 39 /* NB: we only kmalloc()ated enough space for the op field */40 params_op = (uint32_t *)msg->data;41 *params_op = EC_VBNV_CONTEXT_OP_READ;42 43 msg->version = EC_VER_VBNV_CONTEXT;44 msg->command = EC_CMD_VBNV_CONTEXT;45 msg->outsize = para_sz;46 msg->insize = resp_sz;47 48 err = cros_ec_cmd_xfer_status(ecdev, msg);49 if (err < 0) {50 dev_err(dev, "Error sending read request: %d\n", err);51 kfree(msg);52 return err;53 }54 55 memcpy(buf, msg->data, resp_sz);56 57 kfree(msg);58 return resp_sz;59}60 61static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,62 struct bin_attribute *attr, char *buf,63 loff_t pos, size_t count)64{65 struct device *dev = kobj_to_dev(kobj);66 struct cros_ec_dev *ec = to_cros_ec_dev(dev);67 struct cros_ec_device *ecdev = ec->ec_dev;68 struct ec_params_vbnvcontext *params;69 struct cros_ec_command *msg;70 int err;71 const size_t para_sz = sizeof(*params);72 const size_t data_sz = sizeof(params->block);73 74 /* Only write full values */75 if (count != data_sz)76 return -EINVAL;77 78 msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);79 if (!msg)80 return -ENOMEM;81 82 params = (struct ec_params_vbnvcontext *)msg->data;83 params->op = EC_VBNV_CONTEXT_OP_WRITE;84 memcpy(params->block, buf, data_sz);85 86 msg->version = EC_VER_VBNV_CONTEXT;87 msg->command = EC_CMD_VBNV_CONTEXT;88 msg->outsize = para_sz;89 msg->insize = 0;90 91 err = cros_ec_cmd_xfer_status(ecdev, msg);92 if (err < 0) {93 dev_err(dev, "Error sending write request: %d\n", err);94 kfree(msg);95 return err;96 }97 98 kfree(msg);99 return data_sz;100}101 102static BIN_ATTR_RW(vboot_context, 16);103 104static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {105 &bin_attr_vboot_context,106 NULL107};108 109static const struct attribute_group cros_ec_vbc_attr_group = {110 .name = "vbc",111 .bin_attrs = cros_ec_vbc_bin_attrs,112};113 114static int cros_ec_vbc_probe(struct platform_device *pd)115{116 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);117 struct device *dev = &pd->dev;118 int ret;119 120 ret = sysfs_create_group(&ec_dev->class_dev.kobj,121 &cros_ec_vbc_attr_group);122 if (ret < 0)123 dev_err(dev, "failed to create %s attributes. err=%d\n",124 cros_ec_vbc_attr_group.name, ret);125 126 return ret;127}128 129static void cros_ec_vbc_remove(struct platform_device *pd)130{131 struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);132 133 sysfs_remove_group(&ec_dev->class_dev.kobj,134 &cros_ec_vbc_attr_group);135}136 137static const struct platform_device_id cros_ec_vbc_id[] = {138 { DRV_NAME, 0 },139 {}140};141MODULE_DEVICE_TABLE(platform, cros_ec_vbc_id);142 143static struct platform_driver cros_ec_vbc_driver = {144 .driver = {145 .name = DRV_NAME,146 },147 .probe = cros_ec_vbc_probe,148 .remove_new = cros_ec_vbc_remove,149 .id_table = cros_ec_vbc_id,150};151 152module_platform_driver(cros_ec_vbc_driver);153 154MODULE_LICENSE("GPL");155MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");156