From: Bill Richardson <wfrichar@xxxxxxxxxxxx> This patch adds a device interface to access the Chrome OS Embedded Controller from user-space. Signed-off-by: Bill Richardson <wfrichar@xxxxxxxxxxxx> Reviewed-by: Simon Glass <sjg@xxxxxxxxxx> Signed-off-by: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> --- Changes since v1: - The cros_ec_dev driver does not belong to drivers/mfd (Lee Jones) - Don't call class_create in the probe function (Gwendal Grignou) - Don't use the deprecated register_chrdev() function (Gwendal Grignou) - Remove struct cros_ec_device *ec global variable (Lee Jones) - Arrange structures to be 64-bit safe instead using the IOCTL compact API (Alan Cox) - Use _CHARDEV instead of _DEV as a postfix to denote that is a character device user-space interface (Lee Jones) - Remove the CROS_CLASS_NAME define and just use the name directly (Lee Jones) - Remove unncessary include headers (Lee Jones) - Add a newline when appropiate and remove double new lines (Lee Jones) - If *offset == 0, there is no need to do *offset +=, just use = (Lee Jones) - Use dev_err() instead of pr_err() when possible (Lee Jones) - Remove unnecesary goto and just return an error instead (Lee Jones) - Don't set .owner to THIS_MODULE since that is made by the core (Lee Jones) - Document the ioctl number used in Documentation/ioctl/ioctl-number.txt Documentation/ioctl/ioctl-number.txt | 1 + drivers/platform/chrome/Kconfig | 14 +- drivers/platform/chrome/Makefile | 1 + drivers/platform/chrome/cros_ec_dev.c | 268 ++++++++++++++++++++++++++++++++++ drivers/platform/chrome/cros_ec_dev.h | 47 ++++++ 5 files changed, 328 insertions(+), 3 deletions(-) create mode 100644 drivers/platform/chrome/cros_ec_dev.c create mode 100644 drivers/platform/chrome/cros_ec_dev.h diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt index 8136e1f..51f4221 100644 --- a/Documentation/ioctl/ioctl-number.txt +++ b/Documentation/ioctl/ioctl-number.txt @@ -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@xxxxxxxxxx> +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@xxxxxxxxxxxxxxxx> 0xF4 00-1F video/mbxfb.h mbxfb diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index 440ed77..75dc514 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -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 @@ -38,5 +38,13 @@ 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. endif # CHROMEOS_PLATFORMS diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index 2b860ca..10f1361 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o +obj-$(CONFIG_CROS_EC_CHARDEV) += cros_ec_dev.o diff --git a/drivers/platform/chrome/cros_ec_dev.c b/drivers/platform/chrome/cros_ec_dev.c new file mode 100644 index 0000000..04cc8eb --- /dev/null +++ b/drivers/platform/chrome/cros_ec_dev.c @@ -0,0 +1,268 @@ +/* + * 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-dev", + }, + .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@xxxxxxxxxxxx>"); +MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller"); +MODULE_VERSION("1.0"); +MODULE_LICENSE("GPL"); diff --git a/drivers/platform/chrome/cros_ec_dev.h b/drivers/platform/chrome/cros_ec_dev.h new file mode 100644 index 0000000..15c54c4 --- /dev/null +++ b/drivers/platform/chrome/cros_ec_dev.h @@ -0,0 +1,47 @@ +/* + * 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_ */ -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
