From: Enric Balletbo i Serra Date: Mon, 2 Sep 2019 09:53:02 +0000 (+0200) Subject: mfd / platform: cros_ec: Miscellaneous character device to talk with the EC X-Git-Tag: v5.4-rc1~108^2~5^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=eda2e30c6684d67288edb841c6125d48c608a242;p=platform%2Fkernel%2Flinux-rpi.git mfd / platform: cros_ec: Miscellaneous character device to talk with the EC That's a driver to talk with the ChromeOS Embedded Controller via a miscellaneous character device, it creates an entry in /dev for every instance and implements basic file operations for communicating with the Embedded Controller with an userspace application. The API is moved to the uapi folder, which is supposed to contain the user space API of the kernel. Note that this will replace current character device interface implemented in the cros-ec-dev driver in the MFD subsystem. The idea is to move all the functionality that extends the bounds of what MFD was designed to platform/chrome subsystem. Signed-off-by: Enric Balletbo i Serra Acked-by: Andy Shevchenko Reviewed-by: Gwendal Grignou Tested-by: Gwendal Grignou Signed-off-by: Lee Jones --- diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c index 41dccce..4c96445 100644 --- a/drivers/mfd/cros_ec_dev.c +++ b/drivers/mfd/cros_ec_dev.c @@ -7,15 +7,17 @@ #include #include +#include +#include #include #include +#include #include #include #include #include #include -#include "cros_ec_dev.h" #define DRV_NAME "cros-ec-dev" diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index eaeb04e..bd3524b 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -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 diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index 12ff8de..477ec3d 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -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 diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c new file mode 100644 index 0000000..174f940 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_chardev.c @@ -0,0 +1,251 @@ +// 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#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 "); +MODULE_DESCRIPTION("ChromeOS EC Miscellaneous Character Driver"); +MODULE_LICENSE("GPL"); diff --git a/drivers/mfd/cros_ec_dev.h b/include/linux/platform_data/cros_ec_chardev.h similarity index 83% rename from drivers/mfd/cros_ec_dev.h rename to include/linux/platform_data/cros_ec_chardev.h index 7a42c3e..6600b54 100644 --- a/drivers/mfd/cros_ec_dev.h +++ b/include/linux/platform_data/cros_ec_chardev.h @@ -1,15 +1,17 @@ -/* 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 #include #include + #include #define CROS_EC_DEV_VERSION "1.0.0"