On Fri, Jan 2, 2015 at 5:32 AM, Javier Martinez Canillas
<javier.marti...@collabora.co.uk> wrote:
>
> From: Bill Richardson <wfric...@chromium.org>
>
> This patch adds a device interface to access the
> Chrome OS Embedded Controller from user-space.
>
> Signed-off-by: Bill Richardson <wfric...@chromium.org>
> Reviewed-by: Simon Glass <s...@google.com>
> Signed-off-by: Javier Martinez Canillas <javier.marti...@collabora.co.uk>
Reviewed-by: Gwendal Grignou <gwen...@chromium.org>
> ---
>
> 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:aherr...@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:tho...@winischhofer.net>
> 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 <wfric...@chromium.org>");
> +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_ */
> --
> 2.1.3
>
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