// SPDX-License-Identifier: GPL-2.0+
// Expose the vboot context nvram to userspace
//
// Copyright (C) 2012 Google, Inc.
// Copyright (C) 2015 Collabora Ltd.

#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/slab.h>

#define DRV_NAME "cros-ec-vbc"

static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
                                  const struct bin_attribute *att, char *buf,
                                  loff_t pos, size_t count)
{
        struct device *dev = kobj_to_dev(kobj);
        struct cros_ec_dev *ec = to_cros_ec_dev(dev);
        struct cros_ec_device *ecdev = ec->ec_dev;
        struct cros_ec_command *msg;
        /*
         * This should be a pointer to the same type as op field in
         * struct ec_params_vbnvcontext.
         */
        uint32_t *params_op;
        int err;
        const size_t para_sz = sizeof(*params_op);
        const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
        const size_t payload = max(para_sz, resp_sz);

        msg = kmalloc(sizeof(*msg) + payload, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        /* NB: we only kmalloc()ated enough space for the op field */
        params_op = (uint32_t *)msg->data;
        *params_op = EC_VBNV_CONTEXT_OP_READ;

        msg->version = EC_VER_VBNV_CONTEXT;
        msg->command = EC_CMD_VBNV_CONTEXT;
        msg->outsize = para_sz;
        msg->insize = resp_sz;

        err = cros_ec_cmd_xfer_status(ecdev, msg);
        if (err < 0) {
                dev_err(dev, "Error sending read request: %d\n", err);
                kfree(msg);
                return err;
        }

        memcpy(buf, msg->data, resp_sz);

        kfree(msg);
        return resp_sz;
}

static ssize_t vboot_context_write(struct file *filp, struct kobject *kobj,
                                   const struct bin_attribute *attr, char *buf,
                                   loff_t pos, size_t count)
{
        struct device *dev = kobj_to_dev(kobj);
        struct cros_ec_dev *ec = to_cros_ec_dev(dev);
        struct cros_ec_device *ecdev = ec->ec_dev;
        struct ec_params_vbnvcontext *params;
        struct cros_ec_command *msg;
        int err;
        const size_t para_sz = sizeof(*params);
        const size_t data_sz = sizeof(params->block);

        /* Only write full values */
        if (count != data_sz)
                return -EINVAL;

        msg = kmalloc(sizeof(*msg) + para_sz, GFP_KERNEL);
        if (!msg)
                return -ENOMEM;

        params = (struct ec_params_vbnvcontext *)msg->data;
        params->op = EC_VBNV_CONTEXT_OP_WRITE;
        memcpy(params->block, buf, data_sz);

        msg->version = EC_VER_VBNV_CONTEXT;
        msg->command = EC_CMD_VBNV_CONTEXT;
        msg->outsize = para_sz;
        msg->insize = 0;

        err = cros_ec_cmd_xfer_status(ecdev, msg);
        if (err < 0) {
                dev_err(dev, "Error sending write request: %d\n", err);
                kfree(msg);
                return err;
        }

        kfree(msg);
        return data_sz;
}

static const BIN_ATTR_RW(vboot_context, 16);

static const struct bin_attribute *const cros_ec_vbc_bin_attrs[] = {
        &bin_attr_vboot_context,
        NULL
};

static const struct attribute_group cros_ec_vbc_attr_group = {
        .name = "vbc",
        .bin_attrs = cros_ec_vbc_bin_attrs,
};

static int cros_ec_vbc_probe(struct platform_device *pd)
{
        struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);
        struct device *dev = &pd->dev;
        int ret;

        ret = sysfs_create_group(&ec_dev->class_dev.kobj,
                                 &cros_ec_vbc_attr_group);
        if (ret < 0)
                dev_err(dev, "failed to create %s attributes. err=%d\n",
                        cros_ec_vbc_attr_group.name, ret);

        return ret;
}

static void cros_ec_vbc_remove(struct platform_device *pd)
{
        struct cros_ec_dev *ec_dev = dev_get_drvdata(pd->dev.parent);

        sysfs_remove_group(&ec_dev->class_dev.kobj,
                           &cros_ec_vbc_attr_group);
}

static const struct platform_device_id cros_ec_vbc_id[] = {
        { DRV_NAME, 0 },
        {}
};
MODULE_DEVICE_TABLE(platform, cros_ec_vbc_id);

static struct platform_driver cros_ec_vbc_driver = {
        .driver = {
                .name = DRV_NAME,
        },
        .probe = cros_ec_vbc_probe,
        .remove = cros_ec_vbc_remove,
        .id_table = cros_ec_vbc_id,
};

module_platform_driver(cros_ec_vbc_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Expose the vboot context nvram to userspace");