platform/chrome: Add Chrome OS EC userspace device interface (e7c256fb) · Commits · e / devices / android_kernel_teracube_mt6765

Documentation/ioctl/ioctl-number.txt

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		@@ -321,6 +321,7 @@ Code Seq#(hex) Include File Comments
		0xDB 00-0F drivers/char/mwave/mwavepub.h
		0xDD 00-3F ZFCP device driver see drivers/s390/scsi/
		<mailto:aherrman@de.ibm.com>
		0xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
		0xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
		<mailto:thomas@winischhofer.net>
		0xF4 00-1F video/mbxfb.h mbxfb

drivers/platform/chrome/Kconfig

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		@@ -4,7 +4,7 @@

		menuconfig CHROME_PLATFORMS
		bool "Platform support for Chrome hardware"
		depends on X86
		depends on X86 \|\| ARM
		---help---
		Say Y here to get to see options for platform support for
		various Chromebooks and Chromeboxes. This option alone does
		@@ -16,8 +16,7 @@ if CHROME_PLATFORMS

		config CHROMEOS_LAPTOP
		tristate "Chrome OS Laptop"
		depends on I2C
		depends on DMI
		depends on I2C && DMI && X86
		---help---
		This driver instantiates i2c and smbus devices such as
		light sensors and touchpads.
		@@ -27,6 +26,7 @@ config CHROMEOS_LAPTOP

		config CHROMEOS_PSTORE
		tristate "Chrome OS pstore support"
		depends on X86
		---help---
		This module instantiates the persistent storage on x86 ChromeOS
		devices. It can be used to store away console logs and crash
		@@ -38,6 +38,14 @@ config CHROMEOS_PSTORE
		If you have a supported Chromebook, choose Y or M here.
		The module will be called chromeos_pstore.

		config CROS_EC_CHARDEV
		tristate "Chrome OS Embedded Controller userspace device interface"
		depends on MFD_CROS_EC
		---help---
		This driver adds support to talk with the ChromeOS EC from userspace.

		If you have a supported Chromebook, choose Y or M here.
		The module will be called cros_ec_dev.

		config CROS_EC_LPC
		tristate "ChromeOS Embedded Controller (LPC)"

drivers/platform/chrome/Makefile

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Original line number	Diff line number	Diff line

		obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o
		obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o
		obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_dev.o
		obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpc.o

drivers/platform/chrome/cros_ec_dev.c

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		/*
		* cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
		*
		* Copyright (C) 2014 Google, Inc.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program. If not, see <http://www.gnu.org/licenses/>.
		*/

		#include <linux/fs.h>
		#include <linux/module.h>
		#include <linux/platform_device.h>
		#include <linux/uaccess.h>

		#include "cros_ec_dev.h"

		/* Device variables */
		#define CROS_MAX_DEV 128
		static struct class *cros_class;
		static int ec_major;

		/* Basic communication */
		static int ec_get_version(struct cros_ec_device ec, char str, int maxlen)
		{
		struct ec_response_get_version *resp;
		static const char * const current_image_name[] = {
		"unknown", "read-only", "read-write", "invalid",
		};
		struct cros_ec_command msg = {
		.version = 0,
		.command = EC_CMD_GET_VERSION,
		.outdata = { 0 },
		.outsize = 0,
		.indata = { 0 },
		.insize = sizeof(*resp),
		};
		int ret;

		ret = cros_ec_cmd_xfer(ec, &msg);
		if (ret < 0)
		return ret;

		if (msg.result != EC_RES_SUCCESS) {
		snprintf(str, maxlen,
		"%s\nUnknown EC version: EC returned %d\n",
		CROS_EC_DEV_VERSION, msg.result);
		return 0;
		}

		resp = (struct ec_response_get_version *)msg.indata;
		if (resp->current_image >= ARRAY_SIZE(current_image_name))
		resp->current_image = 3; /* invalid */

		snprintf(str, maxlen, "%s\n%s\n%s\n\%s\n", CROS_EC_DEV_VERSION,
		resp->version_string_ro, resp->version_string_rw,
		current_image_name[resp->current_image]);

		return 0;
		}

		/* Device file ops */
		static int ec_device_open(struct inode inode, struct file filp)
		{
		filp->private_data = container_of(inode->i_cdev,
		struct cros_ec_device, cdev);
		return 0;
		}

		static int ec_device_release(struct inode inode, struct file filp)
		{
		return 0;
		}

		static ssize_t ec_device_read(struct file filp, char __user buffer,
		size_t length, loff_t *offset)
		{
		struct cros_ec_device *ec = filp->private_data;
		char msg[sizeof(struct ec_response_get_version) +
		sizeof(CROS_EC_DEV_VERSION)];
		size_t count;
		int ret;

		if (*offset != 0)
		return 0;

		ret = ec_get_version(ec, msg, sizeof(msg));
		if (ret)
		return ret;

		count = min(length, strlen(msg));

		if (copy_to_user(buffer, msg, count))
		return -EFAULT;

		*offset = count;
		return count;
		}

		/* Ioctls */
		static long ec_device_ioctl_xcmd(struct cros_ec_device ec, void __user arg)
		{
		long ret;
		struct cros_ec_command s_cmd = { };

		if (copy_from_user(&s_cmd, arg, sizeof(s_cmd)))
		return -EFAULT;

		ret = cros_ec_cmd_xfer(ec, &s_cmd);
		/* Only copy data to userland if data was received. */
		if (ret < 0)
		return ret;

		if (copy_to_user(arg, &s_cmd, sizeof(s_cmd)))
		return -EFAULT;

		return 0;
		}

		static long ec_device_ioctl_readmem(struct cros_ec_device ec, void __user arg)
		{
		struct cros_ec_readmem s_mem = { };
		long num;

		/* Not every platform supports direct reads */
		if (!ec->cmd_readmem)
		return -ENOTTY;

		if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
		return -EFAULT;

		num = ec->cmd_readmem(ec, s_mem.offset, s_mem.bytes, s_mem.buffer);
		if (num <= 0)
		return num;

		if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
		return -EFAULT;

		return 0;
		}

		static long ec_device_ioctl(struct file *filp, unsigned int cmd,
		unsigned long arg)
		{
		struct cros_ec_device *ec = filp->private_data;

		if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
		return -ENOTTY;

		switch (cmd) {
		case CROS_EC_DEV_IOCXCMD:
		return ec_device_ioctl_xcmd(ec, (void __user *)arg);
		case CROS_EC_DEV_IOCRDMEM:
		return ec_device_ioctl_readmem(ec, (void __user *)arg);
		}

		return -ENOTTY;
		}

		/* Module initialization */
		static const struct file_operations fops = {
		.open = ec_device_open,
		.release = ec_device_release,
		.read = ec_device_read,
		.unlocked_ioctl = ec_device_ioctl,
		};

		static int ec_device_probe(struct platform_device *pdev)
		{
		struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
		int retval = -ENOTTY;
		dev_t devno = MKDEV(ec_major, 0);

		/* Instantiate it (and remember the EC) */
		cdev_init(&ec->cdev, &fops);

		retval = cdev_add(&ec->cdev, devno, 1);
		if (retval) {
		dev_err(&pdev->dev, ": failed to add character device\n");
		return retval;
		}

		ec->vdev = device_create(cros_class, NULL, devno, ec,
		CROS_EC_DEV_NAME);
		if (IS_ERR(ec->vdev)) {
		retval = PTR_ERR(ec->vdev);
		dev_err(&pdev->dev, ": failed to create device\n");
		cdev_del(&ec->cdev);
		return retval;
		}

		return 0;
		}

		static int ec_device_remove(struct platform_device *pdev)
		{
		struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);

		device_destroy(cros_class, MKDEV(ec_major, 0));
		cdev_del(&ec->cdev);
		return 0;
		}

		static struct platform_driver cros_ec_dev_driver = {
		.driver = {
		.name = "cros-ec-ctl",
		},
		.probe = ec_device_probe,
		.remove = ec_device_remove,
		};

		static int __init cros_ec_dev_init(void)
		{
		int ret;
		dev_t dev = 0;

		cros_class = class_create(THIS_MODULE, "chromeos");
		if (IS_ERR(cros_class)) {
		pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
		return PTR_ERR(cros_class);
		}

		/* Get a range of minor numbers (starting with 0) to work with */
		ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
		if (ret < 0) {
		pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
		goto failed_chrdevreg;
		}
		ec_major = MAJOR(dev);

		/* Register the driver */
		ret = platform_driver_register(&cros_ec_dev_driver);
		if (ret < 0) {
		pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
		goto failed_devreg;
		}
		return 0;

		failed_devreg:
		unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
		failed_chrdevreg:
		class_destroy(cros_class);
		return ret;
		}

		static void __exit cros_ec_dev_exit(void)
		{
		platform_driver_unregister(&cros_ec_dev_driver);
		unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
		class_destroy(cros_class);
		}

		module_init(cros_ec_dev_init);
		module_exit(cros_ec_dev_exit);

		MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
		MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
		MODULE_VERSION("1.0");
		MODULE_LICENSE("GPL");

drivers/platform/chrome/cros_ec_dev.h

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		/*
		* cros_ec_dev - expose the Chrome OS Embedded Controller to userspace
		*
		* Copyright (C) 2014 Google, Inc.
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		* the Free Software Foundation; either version 2 of the License, or
		* (at your option) any later version.
		*
		* This program is distributed in the hope that it will be useful,
		* but WITHOUT ANY WARRANTY; without even the implied warranty of
		* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
		* GNU General Public License for more details.
		*
		* You should have received a copy of the GNU General Public License
		* along with this program. If not, see <http://www.gnu.org/licenses/>.
		*/

		#ifndef _CROS_EC_DEV_H_
		#define _CROS_EC_DEV_H_

		#include <linux/ioctl.h>
		#include <linux/types.h>
		#include <linux/mfd/cros_ec.h>

		#define CROS_EC_DEV_NAME "cros_ec"
		#define CROS_EC_DEV_VERSION "1.0.0"

		/*
		* @offset: within EC_LPC_ADDR_MEMMAP region
		* @bytes: number of bytes to read. zero means "read a string" (including '\0')
		* (at most only EC_MEMMAP_SIZE bytes can be read)
		* @buffer: where to store the result
		* ioctl returns the number of bytes read, negative on error
		*/
		struct cros_ec_readmem {
		uint32_t offset;
		uint32_t bytes;
		uint8_t buffer[EC_MEMMAP_SIZE];
		};

		#define CROS_EC_DEV_IOC 0xEC
		#define CROS_EC_DEV_IOCXCMD _IOWR(CROS_EC_DEV_IOC, 0, struct cros_ec_command)
		#define CROS_EC_DEV_IOCRDMEM _IOWR(CROS_EC_DEV_IOC, 1, struct cros_ec_readmem)

		#endif /* _CROS_EC_DEV_H_ */