mfd / platform: cros_ec: Miscellaneous character device to talk with the EC (eda2e30c) · Commits · 戴 / test

drivers/mfd/cros_ec_dev.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -7,15 +7,17 @@

		#include <linux/fs.h>
		#include <linux/mfd/core.h>
		#include <linux/mfd/cros_ec.h>
		#include <linux/mfd/cros_ec_commands.h>
		#include <linux/module.h>
		#include <linux/mod_devicetable.h>
		#include <linux/platform_data/cros_ec_chardev.h>
		#include <linux/of_platform.h>
		#include <linux/platform_device.h>
		#include <linux/pm.h>
		#include <linux/slab.h>
		#include <linux/uaccess.h>

		#include "cros_ec_dev.h"

		#define DRV_NAME "cros-ec-dev"

drivers/platform/chrome/Kconfig

+11 −0

Original line number	Diff line number	Diff line
		@@ -136,6 +136,17 @@ config CROS_KBD_LED_BACKLIGHT
		To compile this driver as a module, choose M here: the
		module will be called cros_kbd_led_backlight.

		config CROS_EC_CHARDEV
		tristate "ChromeOS EC miscdevice"
		depends on MFD_CROS_EC_CHARDEV
		default MFD_CROS_EC_CHARDEV
		help
		This driver adds file operations support to talk with the
		ChromeOS EC from userspace via a character device.

		To compile this driver as a module, choose M here: the
		module will be called cros_ec_chardev.

		config CROS_EC_LIGHTBAR
		tristate "Chromebook Pixel's lightbar support"
		depends on MFD_CROS_EC_CHARDEV

drivers/platform/chrome/Makefile

+1 −0

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		@@ -15,6 +15,7 @@ cros_ec_lpcs-objs := cros_ec_lpc.o cros_ec_lpc_mec.o
		obj-$(CONFIG_CROS_EC_LPC) += cros_ec_lpcs.o
		obj-$(CONFIG_CROS_EC_PROTO) += cros_ec_proto.o cros_ec_trace.o
		obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT) += cros_kbd_led_backlight.o
		obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_chardev.o
		obj-$(CONFIG_CROS_EC_LIGHTBAR) += cros_ec_lightbar.o
		obj-$(CONFIG_CROS_EC_VBC) += cros_ec_vbc.o
		obj-$(CONFIG_CROS_EC_DEBUGFS) += cros_ec_debugfs.o

drivers/platform/chrome/cros_ec_chardev.c

0 → 100644

+251 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		/*
		* Miscellaneous character driver for ChromeOS Embedded Controller
		*
		* Copyright 2014 Google, Inc.
		* Copyright 2019 Google LLC
		*
		* This file is a rework and part of the code is ported from
		* drivers/mfd/cros_ec_dev.c that was originally written by
		* Bill Richardson.
		*/

		#include <linux/init.h>
		#include <linux/device.h>
		#include <linux/fs.h>
		#include <linux/mfd/cros_ec.h>
		#include <linux/mfd/cros_ec_commands.h>
		#include <linux/miscdevice.h>
		#include <linux/module.h>
		#include <linux/platform_data/cros_ec_chardev.h>
		#include <linux/platform_device.h>
		#include <linux/slab.h>
		#include <linux/types.h>
		#include <linux/uaccess.h>

		#define DRV_NAME "cros-ec-chardev"

		struct chardev_data {
		struct cros_ec_dev *ec_dev;
		struct miscdevice misc;
		};

		static int ec_get_version(struct cros_ec_dev ec, char str, int maxlen)
		{
		static const char * const current_image_name[] = {
		"unknown", "read-only", "read-write", "invalid",
		};
		struct ec_response_get_version *resp;
		struct cros_ec_command *msg;
		int ret;

		msg = kzalloc(sizeof(msg) + sizeof(resp), GFP_KERNEL);
		if (!msg)
		return -ENOMEM;

		msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
		msg->insize = sizeof(*resp);

		ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
		if (ret < 0) {
		snprintf(str, maxlen,
		"Unknown EC version, returned error: %d\n",
		msg->result);
		goto exit;
		}

		resp = (struct ec_response_get_version *)msg->data;
		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]);

		ret = 0;
		exit:
		kfree(msg);
		return ret;
		}

		/*
		* Device file ops
		*/
		static int cros_ec_chardev_open(struct inode inode, struct file filp)
		{
		struct miscdevice *mdev = filp->private_data;
		struct cros_ec_dev *ec_dev = dev_get_drvdata(mdev->parent);

		filp->private_data = ec_dev;
		nonseekable_open(inode, filp);

		return 0;
		}

		static ssize_t cros_ec_chardev_read(struct file filp, char __user buffer,
		size_t length, loff_t *offset)
		{
		char msg[sizeof(struct ec_response_get_version) +
		sizeof(CROS_EC_DEV_VERSION)];
		struct cros_ec_dev *ec = filp->private_data;
		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 cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev ec, void __user arg)
		{
		struct cros_ec_command *s_cmd;
		struct cros_ec_command u_cmd;
		long ret;

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

		if (u_cmd.outsize > EC_MAX_MSG_BYTES \|\|
		u_cmd.insize > EC_MAX_MSG_BYTES)
		return -EINVAL;

		s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
		GFP_KERNEL);
		if (!s_cmd)
		return -ENOMEM;

		if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
		ret = -EFAULT;
		goto exit;
		}

		if (u_cmd.outsize != s_cmd->outsize \|\|
		u_cmd.insize != s_cmd->insize) {
		ret = -EINVAL;
		goto exit;
		}

		s_cmd->command += ec->cmd_offset;
		ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
		/* Only copy data to userland if data was received. */
		if (ret < 0)
		goto exit;

		if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
		ret = -EFAULT;
		exit:
		kfree(s_cmd);
		return ret;
		}

		static long cros_ec_chardev_ioctl_readmem(struct cros_ec_dev *ec,
		void __user *arg)
		{
		struct cros_ec_device *ec_dev = ec->ec_dev;
		struct cros_ec_readmem s_mem = { };
		long num;

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

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

		num = ec_dev->cmd_readmem(ec_dev, 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 num;
		}

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

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

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

		return -ENOTTY;
		}

		static const struct file_operations chardev_fops = {
		.open = cros_ec_chardev_open,
		.read = cros_ec_chardev_read,
		.unlocked_ioctl = cros_ec_chardev_ioctl,
		#ifdef CONFIG_COMPAT
		.compat_ioctl = cros_ec_chardev_ioctl,
		#endif
		};

		static int cros_ec_chardev_probe(struct platform_device *pdev)
		{
		struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent);
		struct cros_ec_platform *ec_platform = dev_get_platdata(ec_dev->dev);
		struct chardev_data *data;

		/* Create a char device: we want to create it anew */
		data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
		if (!data)
		return -ENOMEM;

		data->ec_dev = ec_dev;
		data->misc.minor = MISC_DYNAMIC_MINOR;
		data->misc.fops = &chardev_fops;
		data->misc.name = ec_platform->ec_name;
		data->misc.parent = pdev->dev.parent;

		dev_set_drvdata(&pdev->dev, data);

		return misc_register(&data->misc);
		}

		static int cros_ec_chardev_remove(struct platform_device *pdev)
		{
		struct chardev_data *data = dev_get_drvdata(&pdev->dev);

		misc_deregister(&data->misc);

		return 0;
		}

		static struct platform_driver cros_ec_chardev_driver = {
		.driver = {
		.name = DRV_NAME,
		},
		.probe = cros_ec_chardev_probe,
		.remove = cros_ec_chardev_remove,
		};

		module_platform_driver(cros_ec_chardev_driver);

		MODULE_ALIAS("platform:" DRV_NAME);
		MODULE_AUTHOR("Enric Balletbo i Serra <enric.balletbo@collabora.com>");
		MODULE_DESCRIPTION("ChromeOS EC Miscellaneous Character Driver");
		MODULE_LICENSE("GPL");

drivers/mfd/cros_ec_dev.h→include/linux/platform_data/cros_ec_chardev.h

+6 −4

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0-or-later */
		/* SPDX-License-Identifier: GPL-2.0 */
		/*
		* cros_ec_dev - expose the Chrome OS Embedded Controller to userspace
		* ChromeOS EC device interface.
		*
		* Copyright (C) 2014 Google, Inc.
		*/

		#ifndef _CROS_EC_DEV_H_
		#define _CROS_EC_DEV_H_
		#ifndef _UAPI_LINUX_CROS_EC_DEV_H_
		#define _UAPI_LINUX_CROS_EC_DEV_H_

		#include <linux/bits.h>
		#include <linux/ioctl.h>
		#include <linux/types.h>

		#include <linux/mfd/cros_ec.h>

		#define CROS_EC_DEV_VERSION "1.0.0"

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