136 lines
3.7 KiB
C
136 lines
3.7 KiB
C
/*
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* cros_ec_vbc - Expose the vboot context nvram to userspace
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*
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* Copyright (C) 2015 Collabora Ltd.
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*
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* based on vendor driver,
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*
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* Copyright (C) 2012 The Chromium OS Authors
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/mfd/cros_ec.h>
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#include <linux/mfd/cros_ec_commands.h>
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#include <linux/slab.h>
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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 = container_of(kobj, struct device, 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(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 = container_of(kobj, struct device, 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(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 umode_t cros_ec_vbc_is_visible(struct kobject *kobj,
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struct bin_attribute *a, int n)
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{
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struct device *dev = container_of(kobj, struct device, kobj);
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struct cros_ec_dev *ec = to_cros_ec_dev(dev);
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struct device_node *np = ec->ec_dev->dev->of_node;
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if (IS_ENABLED(CONFIG_OF) && np) {
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if (of_property_read_bool(np, "google,has-vbc-nvram"))
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return a->attr.mode;
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}
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return 0;
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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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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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.is_bin_visible = cros_ec_vbc_is_visible,
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};
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EXPORT_SYMBOL(cros_ec_vbc_attr_group);
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