diff options
Diffstat (limited to 'drivers/platform/chrome/cros_ec_chardev.c')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_chardev.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c new file mode 100644 index 000000000000..08abd7e5c7bf --- /dev/null +++ b/drivers/platform/chrome/cros_ec_chardev.c @@ -0,0 +1,252 @@ +// 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/miscdevice.h> +#include <linux/module.h> +#include <linux/platform_data/cros_ec_chardev.h> +#include <linux/platform_data/cros_ec_commands.h> +#include <linux/platform_data/cros_ec_proto.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"); |