147 lines
3.6 KiB
C
147 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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// Expose the vboot context nvram to userspace
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//
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// Copyright (C) 2012 Google, Inc.
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// Copyright (C) 2015 Collabora Ltd.
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/platform_data/cros_ec_commands.h>
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#include <linux/platform_data/cros_ec_proto.h>
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#include <linux/slab.h>
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#define DRV_NAME "cros-ec-vbc"
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static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
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struct bin_attribute *att, char *buf,
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loff_t pos, size_t count)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct cros_ec_dev *ec = to_cros_ec_dev(dev);
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struct cros_ec_device *ecdev = ec->ec_dev;
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struct ec_params_vbnvcontext *params;
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struct cros_ec_command *msg;
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int err;
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const size_t para_sz = sizeof(params->op);
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const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
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const size_t payload = max(para_sz, resp_sz);
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msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
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if (!msg)
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return -ENOMEM;
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/* NB: we only kmalloc()ated enough space for the op field */
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params = (struct ec_params_vbnvcontext *)msg->data;
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params->op = EC_VBNV_CONTEXT_OP_READ;
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msg->version = EC_VER_VBNV_CONTEXT;
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msg->command = EC_CMD_VBNV_CONTEXT;
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msg->outsize = para_sz;
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msg->insize = resp_sz;
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err = cros_ec_cmd_xfer_status(ecdev, msg);
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if (err < 0) {
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dev_err(dev, "Error sending read request: %d\n", err);
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kfree(msg);
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return err;
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}
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memcpy(buf, msg->data, resp_sz);
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kfree(msg);
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return resp_sz;
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}
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static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
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struct bin_attribute *attr, char *buf,
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loff_t pos, size_t count)
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{
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struct device *dev = kobj_to_dev(kobj);
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struct cros_ec_dev *ec = to_cros_ec_dev(dev);
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struct cros_ec_device *ecdev = ec->ec_dev;
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struct ec_params_vbnvcontext *params;
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struct cros_ec_command *msg;
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int err;
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const size_t para_sz = sizeof(*params);
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const size_t data_sz = sizeof(params->block);
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/* Only write full values */
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if (count != data_sz)
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return -EINVAL;
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msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
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if (!msg)
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return -ENOMEM;
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params = (struct ec_params_vbnvcontext *)msg->data;
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params->op = EC_VBNV_CONTEXT_OP_WRITE;
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memcpy(params->block, buf, data_sz);
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msg->version = EC_VER_VBNV_CONTEXT;
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msg->command = EC_CMD_VBNV_CONTEXT;
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msg->outsize = para_sz;
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msg->insize = 0;
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err = cros_ec_cmd_xfer_status(ecdev, msg);
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if (err < 0) {
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dev_err(dev, "Error sending write request: %d\n", err);
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kfree(msg);
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return err;
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}
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kfree(msg);
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return data_sz;
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}
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static BIN_ATTR_RW(vboot_context, 16);
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static struct bin_attribute *cros_ec_vbc_bin_attrs[] = {
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&bin_attr_vboot_context,
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NULL
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};
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static const struct attribute_group cros_ec_vbc_attr_group = {
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.name = "vbc",
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.bin_attrs = cros_ec_vbc_bin_attrs,
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};
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static int cros_ec_vbc_probe(struct platform_device *pd)
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{
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struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
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struct device *dev = &pd->dev;
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int ret;
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ret = sysfs_create_group(&ec_dev->class_dev.kobj,
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&cros_ec_vbc_attr_group);
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if (ret < 0)
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dev_err(dev, "failed to create %s attributes. err=%d\n",
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cros_ec_vbc_attr_group.name, ret);
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return ret;
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}
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static int cros_ec_vbc_remove(struct platform_device *pd)
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{
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struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
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sysfs_remove_group(&ec_dev->class_dev.kobj,
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&cros_ec_vbc_attr_group);
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return 0;
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}
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static struct platform_driver cros_ec_vbc_driver = {
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.driver = {
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.name = DRV_NAME,
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},
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.probe = cros_ec_vbc_probe,
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.remove = cros_ec_vbc_remove,
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};
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module_platform_driver(cros_ec_vbc_driver);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");
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MODULE_ALIAS("platform:" DRV_NAME);
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