lkml.org 
[lkml]   [2015]   [Jan]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH RESEND v2 4/7] platform/chrome: Add Chrome OS EC userspace device interface
    On Fri, Jan 2, 2015 at 5:32 AM, Javier Martinez Canillas
    <javier.martinez@collabora.co.uk> wrote:
    >
    > From: Bill Richardson <wfrichar@chromium.org>
    >
    > This patch adds a device interface to access the
    > Chrome OS Embedded Controller from user-space.
    >
    > Signed-off-by: Bill Richardson <wfrichar@chromium.org>
    > Reviewed-by: Simon Glass <sjg@google.com>
    > Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
    Reviewed-by: Gwendal Grignou <gwendal@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: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
    > 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@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
    >


    \
     
     \ /
      Last update: 2015-01-14 01:01    [W:6.159 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site