--- /dev/null
+/*
+ * Copyright (C) 2010 Broadcom
+ * Copyright (C) 2015 Noralf Trønnes
+ * Copyright (C) 2021 Raspberry Pi (Trading) Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/ioctl.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <linux/miscdevice.h>
+#include <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MODULE_NAME "vcio"
+#define VCIO_IOC_MAGIC 100
+#define IOCTL_MBOX_PROPERTY _IOWR(VCIO_IOC_MAGIC, 0, char *)
+#ifdef CONFIG_COMPAT
+#define IOCTL_MBOX_PROPERTY32 _IOWR(VCIO_IOC_MAGIC, 0, compat_uptr_t)
+#endif
+
+struct vcio_data {
+ struct rpi_firmware *fw;
+ struct miscdevice misc_dev;
+};
+
+static int vcio_user_property_list(struct vcio_data *vcio, void *user)
+{
+ u32 *buf, size;
+ int ret;
+
+ /* The first 32-bit is the size of the buffer */
+ if (copy_from_user(&size, user, sizeof(size)))
+ return -EFAULT;
+
+ buf = kmalloc(size, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ if (copy_from_user(buf, user, size)) {
+ kfree(buf);
+ return -EFAULT;
+ }
+
+ /* Strip off protocol encapsulation */
+ ret = rpi_firmware_property_list(vcio->fw, &buf[2], size - 12);
+ if (ret) {
+ kfree(buf);
+ return ret;
+ }
+
+ buf[1] = RPI_FIRMWARE_STATUS_SUCCESS;
+ if (copy_to_user(user, buf, size))
+ ret = -EFAULT;
+
+ kfree(buf);
+
+ return ret;
+}
+
+static int vcio_device_open(struct inode *inode, struct file *file)
+{
+ try_module_get(THIS_MODULE);
+
+ return 0;
+}
+
+static int vcio_device_release(struct inode *inode, struct file *file)
+{
+ module_put(THIS_MODULE);
+
+ return 0;
+}
+
+static long vcio_device_ioctl(struct file *file, unsigned int ioctl_num,
+ unsigned long ioctl_param)
+{
+ struct vcio_data *vcio = container_of(file->private_data,
+ struct vcio_data, misc_dev);
+
+ switch (ioctl_num) {
+ case IOCTL_MBOX_PROPERTY:
+ return vcio_user_property_list(vcio, (void *)ioctl_param);
+ default:
+ pr_err("unknown ioctl: %x\n", ioctl_num);
+ return -EINVAL;
+ }
+}
+
+#ifdef CONFIG_COMPAT
+static long vcio_device_compat_ioctl(struct file *file, unsigned int ioctl_num,
+ unsigned long ioctl_param)
+{
+ struct vcio_data *vcio = container_of(file->private_data,
+ struct vcio_data, misc_dev);
+
+ switch (ioctl_num) {
+ case IOCTL_MBOX_PROPERTY32:
+ return vcio_user_property_list(vcio, compat_ptr(ioctl_param));
+ default:
+ pr_err("unknown ioctl: %x\n", ioctl_num);
+ return -EINVAL;
+ }
+}
+#endif
+
+const struct file_operations vcio_fops = {
+ .unlocked_ioctl = vcio_device_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = vcio_device_compat_ioctl,
+#endif
+ .open = vcio_device_open,
+ .release = vcio_device_release,
+};
+
+static int vcio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct device_node *fw_node;
+ struct rpi_firmware *fw;
+ struct vcio_data *vcio;
+
+ fw_node = of_get_parent(np);
+ if (!fw_node) {
+ dev_err(dev, "Missing firmware node\n");
+ return -ENOENT;
+ }
+
+ fw = rpi_firmware_get(fw_node);
+ of_node_put(fw_node);
+ if (!fw)
+ return -EPROBE_DEFER;
+
+ vcio = devm_kzalloc(dev, sizeof(struct vcio_data), GFP_KERNEL);
+ if (!vcio)
+ return -ENOMEM;
+
+ vcio->fw = fw;
+ vcio->misc_dev.fops = &vcio_fops;
+ vcio->misc_dev.minor = MISC_DYNAMIC_MINOR;
+ vcio->misc_dev.name = "vcio";
+ vcio->misc_dev.parent = dev;
+
+ return misc_register(&vcio->misc_dev);
+}
+
+static int vcio_remove(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+
+ misc_deregister(dev_get_drvdata(dev));
+ return 0;
+}
+
+static const struct of_device_id vcio_ids[] = {
+ { .compatible = "raspberrypi,vcio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, vcio_ids);
+
+static struct platform_driver vcio_driver = {
+ .driver = {
+ .name = MODULE_NAME,
+ .of_match_table = of_match_ptr(vcio_ids),
+ },
+ .probe = vcio_probe,
+ .remove = vcio_remove,
+};
+
+module_platform_driver(vcio_driver);
+
+MODULE_AUTHOR("Gray Girling");
+MODULE_AUTHOR("Noralf Trønnes");
+MODULE_DESCRIPTION("Mailbox userspace access");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:rpi-vcio");