char: broadcom: Add vcio module

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

Add module for accessing the mailbox property channel through
/dev/vcio. Was previously in bcm2708-vcio.
Signed-off-by: NNoralf Trønnes <noralf@tronnes.org>

char: vcio: Add compat ioctl handling

There was no compat ioctl handler, so 32 bit userspace on a
64 bit kernel failed as IOCTL_MBOX_PROPERTY used the size
of char*.
Signed-off-by: NDave Stevenson <dave.stevenson@raspberrypi.org>

char: vcio: Fail probe if rpi_firmware is not found.

Device Tree is now the only supported config mechanism, therefore
uncomment the block of code that fails the probe if the
firmware node can't be found.
Signed-off-by: NDave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/char/broadcom/Kconfig

@@ -15,6 +15,12 @@ config BCM2708_VCMEM
         help
           Helper for videocore memory access and total size allocation.
 
+config BCM_VCIO
+	tristate "Mailbox userspace access"
+	depends on BCM2835_MBOX
+	help
+	  Gives access to the mailbox property channel from userspace.
+
 endif
 
 config BCM2835_DEVGPIOMEM

drivers/char/broadcom/Makefile

 obj-$(CONFIG_BCM2708_VCMEM)	+= vc_mem.o
+obj-$(CONFIG_BCM_VCIO)		+= vcio.o
 obj-$(CONFIG_BCM2835_DEVGPIOMEM)+= bcm2835-gpiomem.o
 obj-$(CONFIG_BCM2835_SMI_DEV)	+= bcm2835_smi_dev.o

drivers/char/broadcom/vcio.c

+/*
+ *  Copyright (C) 2010 Broadcom
+ *  Copyright (C) 2015 Noralf Trønnes
+ *
+ * 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.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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 <soc/bcm2835/raspberrypi-firmware.h>
+
+#define MBOX_CHAN_PROPERTY 8
+
+#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
+
+static struct {
+	dev_t devt;
+	struct cdev cdev;
+	struct class *class;
+	struct rpi_firmware *fw;
+} vcio;
+
+static int vcio_user_property_list(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)
+{
+	switch (ioctl_num) {
+	case IOCTL_MBOX_PROPERTY:
+		return vcio_user_property_list((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)
+{
+	switch (ioctl_num) {
+	case IOCTL_MBOX_PROPERTY32:
+		return vcio_user_property_list(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 __init vcio_init(void)
+{
+	struct device_node *np;
+	static struct device *dev;
+	int ret;
+
+	np = of_find_compatible_node(NULL, NULL,
+				     "raspberrypi,bcm2835-firmware");
+	if (!of_device_is_available(np))
+		return -ENODEV;
+
+	vcio.fw = rpi_firmware_get(np);
+	if (!vcio.fw)
+		return -ENODEV;
+
+	ret = alloc_chrdev_region(&vcio.devt, 0, 1, "vcio");
+	if (ret) {
+		pr_err("failed to allocate device number\n");
+		return ret;
+	}
+
+	cdev_init(&vcio.cdev, &vcio_fops);
+	vcio.cdev.owner = THIS_MODULE;
+	ret = cdev_add(&vcio.cdev, vcio.devt, 1);
+	if (ret) {
+		pr_err("failed to register device\n");
+		goto err_unregister_chardev;
+	}
+
+	/*
+	 * Create sysfs entries
+	 * 'bcm2708_vcio' is used for backwards compatibility so we don't break
+	 * userspace. Raspian has a udev rule that changes the permissions.
+	 */
+	vcio.class = class_create(THIS_MODULE, "bcm2708_vcio");
+	if (IS_ERR(vcio.class)) {
+		ret = PTR_ERR(vcio.class);
+		pr_err("failed to create class\n");
+		goto err_cdev_del;
+	}
+
+	dev = device_create(vcio.class, NULL, vcio.devt, NULL, "vcio");
+	if (IS_ERR(dev)) {
+		ret = PTR_ERR(dev);
+		pr_err("failed to create device\n");
+		goto err_class_destroy;
+	}
+
+	return 0;
+
+err_class_destroy:
+	class_destroy(vcio.class);
+err_cdev_del:
+	cdev_del(&vcio.cdev);
+err_unregister_chardev:
+	unregister_chrdev_region(vcio.devt, 1);
+
+	return ret;
+}
+module_init(vcio_init);
+
+static void __exit vcio_exit(void)
+{
+	device_destroy(vcio.class, vcio.devt);
+	class_destroy(vcio.class);
+	cdev_del(&vcio.cdev);
+	unregister_chrdev_region(vcio.devt, 1);
+}
+module_exit(vcio_exit);
+
+MODULE_AUTHOR("Gray Girling");
+MODULE_AUTHOR("Noralf Trønnes");
+MODULE_DESCRIPTION("Mailbox userspace access");
+MODULE_LICENSE("GPL");