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418 lines
9.9 KiB
418 lines
9.9 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Miscellaneous character driver for ChromeOS Embedded Controller |
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* |
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* Copyright 2014 Google, Inc. |
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* Copyright 2019 Google LLC |
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* |
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* This file is a rework and part of the code is ported from |
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* drivers/mfd/cros_ec_dev.c that was originally written by |
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* Bill Richardson. |
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*/ |
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#include <linux/init.h> |
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#include <linux/device.h> |
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#include <linux/fs.h> |
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#include <linux/miscdevice.h> |
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#include <linux/module.h> |
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#include <linux/notifier.h> |
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#include <linux/platform_data/cros_ec_chardev.h> |
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#include <linux/platform_data/cros_ec_commands.h> |
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#include <linux/platform_data/cros_ec_proto.h> |
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#include <linux/platform_device.h> |
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#include <linux/poll.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <linux/uaccess.h> |
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#define DRV_NAME "cros-ec-chardev" |
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/* Arbitrary bounded size for the event queue */ |
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#define CROS_MAX_EVENT_LEN PAGE_SIZE |
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struct chardev_data { |
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struct cros_ec_dev *ec_dev; |
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struct miscdevice misc; |
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}; |
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struct chardev_priv { |
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struct cros_ec_dev *ec_dev; |
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struct notifier_block notifier; |
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wait_queue_head_t wait_event; |
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unsigned long event_mask; |
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struct list_head events; |
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size_t event_len; |
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}; |
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struct ec_event { |
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struct list_head node; |
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size_t size; |
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u8 event_type; |
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u8 data[]; |
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}; |
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static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen) |
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{ |
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static const char * const current_image_name[] = { |
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"unknown", "read-only", "read-write", "invalid", |
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}; |
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struct ec_response_get_version *resp; |
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struct cros_ec_command *msg; |
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int ret; |
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msg = kzalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL); |
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if (!msg) |
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return -ENOMEM; |
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msg->command = EC_CMD_GET_VERSION + ec->cmd_offset; |
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msg->insize = sizeof(*resp); |
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ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg); |
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if (ret < 0) { |
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snprintf(str, maxlen, |
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"Unknown EC version, returned error: %d\n", |
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msg->result); |
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goto exit; |
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} |
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resp = (struct ec_response_get_version *)msg->data; |
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if (resp->current_image >= ARRAY_SIZE(current_image_name)) |
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resp->current_image = 3; /* invalid */ |
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snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION, |
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resp->version_string_ro, resp->version_string_rw, |
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current_image_name[resp->current_image]); |
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ret = 0; |
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exit: |
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kfree(msg); |
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return ret; |
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} |
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static int cros_ec_chardev_mkbp_event(struct notifier_block *nb, |
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unsigned long queued_during_suspend, |
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void *_notify) |
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{ |
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struct chardev_priv *priv = container_of(nb, struct chardev_priv, |
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notifier); |
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struct cros_ec_device *ec_dev = priv->ec_dev->ec_dev; |
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struct ec_event *event; |
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unsigned long event_bit = 1 << ec_dev->event_data.event_type; |
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int total_size = sizeof(*event) + ec_dev->event_size; |
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if (!(event_bit & priv->event_mask) || |
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(priv->event_len + total_size) > CROS_MAX_EVENT_LEN) |
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return NOTIFY_DONE; |
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event = kzalloc(total_size, GFP_KERNEL); |
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if (!event) |
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return NOTIFY_DONE; |
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event->size = ec_dev->event_size; |
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event->event_type = ec_dev->event_data.event_type; |
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memcpy(event->data, &ec_dev->event_data.data, ec_dev->event_size); |
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spin_lock(&priv->wait_event.lock); |
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list_add_tail(&event->node, &priv->events); |
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priv->event_len += total_size; |
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wake_up_locked(&priv->wait_event); |
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spin_unlock(&priv->wait_event.lock); |
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return NOTIFY_OK; |
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} |
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static struct ec_event *cros_ec_chardev_fetch_event(struct chardev_priv *priv, |
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bool fetch, bool block) |
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{ |
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struct ec_event *event; |
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int err; |
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spin_lock(&priv->wait_event.lock); |
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if (!block && list_empty(&priv->events)) { |
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event = ERR_PTR(-EWOULDBLOCK); |
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goto out; |
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} |
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if (!fetch) { |
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event = NULL; |
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goto out; |
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} |
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err = wait_event_interruptible_locked(priv->wait_event, |
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!list_empty(&priv->events)); |
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if (err) { |
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event = ERR_PTR(err); |
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goto out; |
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} |
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event = list_first_entry(&priv->events, struct ec_event, node); |
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list_del(&event->node); |
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priv->event_len -= sizeof(*event) + event->size; |
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out: |
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spin_unlock(&priv->wait_event.lock); |
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return event; |
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} |
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/* |
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* Device file ops |
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*/ |
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static int cros_ec_chardev_open(struct inode *inode, struct file *filp) |
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{ |
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struct miscdevice *mdev = filp->private_data; |
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struct cros_ec_dev *ec_dev = dev_get_drvdata(mdev->parent); |
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struct chardev_priv *priv; |
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int ret; |
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priv = kzalloc(sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->ec_dev = ec_dev; |
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filp->private_data = priv; |
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INIT_LIST_HEAD(&priv->events); |
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init_waitqueue_head(&priv->wait_event); |
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nonseekable_open(inode, filp); |
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priv->notifier.notifier_call = cros_ec_chardev_mkbp_event; |
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ret = blocking_notifier_chain_register(&ec_dev->ec_dev->event_notifier, |
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&priv->notifier); |
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if (ret) { |
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dev_err(ec_dev->dev, "failed to register event notifier\n"); |
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kfree(priv); |
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} |
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return ret; |
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} |
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static __poll_t cros_ec_chardev_poll(struct file *filp, poll_table *wait) |
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{ |
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struct chardev_priv *priv = filp->private_data; |
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poll_wait(filp, &priv->wait_event, wait); |
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if (list_empty(&priv->events)) |
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return 0; |
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return EPOLLIN | EPOLLRDNORM; |
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} |
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static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer, |
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size_t length, loff_t *offset) |
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{ |
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char msg[sizeof(struct ec_response_get_version) + |
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sizeof(CROS_EC_DEV_VERSION)]; |
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struct chardev_priv *priv = filp->private_data; |
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struct cros_ec_dev *ec_dev = priv->ec_dev; |
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size_t count; |
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int ret; |
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if (priv->event_mask) { /* queued MKBP event */ |
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struct ec_event *event; |
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event = cros_ec_chardev_fetch_event(priv, length != 0, |
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!(filp->f_flags & O_NONBLOCK)); |
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if (IS_ERR(event)) |
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return PTR_ERR(event); |
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/* |
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* length == 0 is special - no IO is done but we check |
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* for error conditions. |
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*/ |
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if (length == 0) |
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return 0; |
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/* The event is 1 byte of type plus the payload */ |
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count = min(length, event->size + 1); |
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ret = copy_to_user(buffer, &event->event_type, count); |
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kfree(event); |
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if (ret) /* the copy failed */ |
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return -EFAULT; |
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*offset = count; |
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return count; |
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} |
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/* |
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* Legacy behavior if no event mask is defined |
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*/ |
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if (*offset != 0) |
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return 0; |
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ret = ec_get_version(ec_dev, msg, sizeof(msg)); |
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if (ret) |
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return ret; |
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count = min(length, strlen(msg)); |
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if (copy_to_user(buffer, msg, count)) |
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return -EFAULT; |
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*offset = count; |
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return count; |
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} |
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static int cros_ec_chardev_release(struct inode *inode, struct file *filp) |
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{ |
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struct chardev_priv *priv = filp->private_data; |
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struct cros_ec_dev *ec_dev = priv->ec_dev; |
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struct ec_event *event, *e; |
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blocking_notifier_chain_unregister(&ec_dev->ec_dev->event_notifier, |
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&priv->notifier); |
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list_for_each_entry_safe(event, e, &priv->events, node) { |
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list_del(&event->node); |
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kfree(event); |
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} |
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kfree(priv); |
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return 0; |
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} |
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/* |
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* Ioctls |
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*/ |
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static long cros_ec_chardev_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg) |
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{ |
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struct cros_ec_command *s_cmd; |
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struct cros_ec_command u_cmd; |
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long ret; |
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if (copy_from_user(&u_cmd, arg, sizeof(u_cmd))) |
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return -EFAULT; |
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if (u_cmd.outsize > EC_MAX_MSG_BYTES || |
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u_cmd.insize > EC_MAX_MSG_BYTES) |
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return -EINVAL; |
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s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize), |
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GFP_KERNEL); |
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if (!s_cmd) |
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return -ENOMEM; |
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if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) { |
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ret = -EFAULT; |
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goto exit; |
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} |
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if (u_cmd.outsize != s_cmd->outsize || |
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u_cmd.insize != s_cmd->insize) { |
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ret = -EINVAL; |
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goto exit; |
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} |
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s_cmd->command += ec->cmd_offset; |
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ret = cros_ec_cmd_xfer_status(ec->ec_dev, s_cmd); |
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/* Only copy data to userland if data was received. */ |
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if (ret < 0) |
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goto exit; |
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if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize)) |
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ret = -EFAULT; |
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exit: |
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kfree(s_cmd); |
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return ret; |
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} |
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static long cros_ec_chardev_ioctl_readmem(struct cros_ec_dev *ec, |
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void __user *arg) |
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{ |
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struct cros_ec_device *ec_dev = ec->ec_dev; |
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struct cros_ec_readmem s_mem = { }; |
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long num; |
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/* Not every platform supports direct reads */ |
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if (!ec_dev->cmd_readmem) |
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return -ENOTTY; |
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if (copy_from_user(&s_mem, arg, sizeof(s_mem))) |
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return -EFAULT; |
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num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes, |
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s_mem.buffer); |
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if (num <= 0) |
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return num; |
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if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem))) |
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return -EFAULT; |
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return num; |
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} |
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static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd, |
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unsigned long arg) |
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{ |
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struct chardev_priv *priv = filp->private_data; |
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struct cros_ec_dev *ec = priv->ec_dev; |
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if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC) |
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return -ENOTTY; |
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switch (cmd) { |
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case CROS_EC_DEV_IOCXCMD: |
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return cros_ec_chardev_ioctl_xcmd(ec, (void __user *)arg); |
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case CROS_EC_DEV_IOCRDMEM: |
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return cros_ec_chardev_ioctl_readmem(ec, (void __user *)arg); |
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case CROS_EC_DEV_IOCEVENTMASK: |
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priv->event_mask = arg; |
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return 0; |
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} |
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return -ENOTTY; |
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} |
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static const struct file_operations chardev_fops = { |
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.open = cros_ec_chardev_open, |
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.poll = cros_ec_chardev_poll, |
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.read = cros_ec_chardev_read, |
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.release = cros_ec_chardev_release, |
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.unlocked_ioctl = cros_ec_chardev_ioctl, |
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#ifdef CONFIG_COMPAT |
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.compat_ioctl = cros_ec_chardev_ioctl, |
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#endif |
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}; |
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static int cros_ec_chardev_probe(struct platform_device *pdev) |
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{ |
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struct cros_ec_dev *ec_dev = dev_get_drvdata(pdev->dev.parent); |
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struct cros_ec_platform *ec_platform = dev_get_platdata(ec_dev->dev); |
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struct chardev_data *data; |
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/* Create a char device: we want to create it anew */ |
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data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
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if (!data) |
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return -ENOMEM; |
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data->ec_dev = ec_dev; |
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data->misc.minor = MISC_DYNAMIC_MINOR; |
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data->misc.fops = &chardev_fops; |
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data->misc.name = ec_platform->ec_name; |
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data->misc.parent = pdev->dev.parent; |
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dev_set_drvdata(&pdev->dev, data); |
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return misc_register(&data->misc); |
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} |
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static int cros_ec_chardev_remove(struct platform_device *pdev) |
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{ |
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struct chardev_data *data = dev_get_drvdata(&pdev->dev); |
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misc_deregister(&data->misc); |
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return 0; |
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} |
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static struct platform_driver cros_ec_chardev_driver = { |
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.driver = { |
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.name = DRV_NAME, |
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}, |
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.probe = cros_ec_chardev_probe, |
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.remove = cros_ec_chardev_remove, |
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}; |
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module_platform_driver(cros_ec_chardev_driver); |
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MODULE_ALIAS("platform:" DRV_NAME); |
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MODULE_AUTHOR("Enric Balletbo i Serra <[email protected]>"); |
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MODULE_DESCRIPTION("ChromeOS EC Miscellaneous Character Driver"); |
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MODULE_LICENSE("GPL");
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