diff options
Diffstat (limited to 'drivers/platform')
| -rw-r--r-- | drivers/platform/chrome/cros_ec_chardev.c | 177 |
1 files changed, 172 insertions, 5 deletions
diff --git a/drivers/platform/chrome/cros_ec_chardev.c b/drivers/platform/chrome/cros_ec_chardev.c index 08abd7e5c7bf..74ded441bb50 100644 --- a/drivers/platform/chrome/cros_ec_chardev.c +++ b/drivers/platform/chrome/cros_ec_chardev.c @@ -16,21 +16,42 @@ #include <linux/mfd/cros_ec.h> #include <linux/miscdevice.h> #include <linux/module.h> +#include <linux/notifier.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/poll.h> #include <linux/slab.h> #include <linux/types.h> #include <linux/uaccess.h> #define DRV_NAME "cros-ec-chardev" +/* Arbitrary bounded size for the event queue */ +#define CROS_MAX_EVENT_LEN PAGE_SIZE + struct chardev_data { struct cros_ec_dev *ec_dev; struct miscdevice misc; }; +struct chardev_priv { + struct cros_ec_dev *ec_dev; + struct notifier_block notifier; + wait_queue_head_t wait_event; + unsigned long event_mask; + struct list_head events; + size_t event_len; +}; + +struct ec_event { + struct list_head node; + size_t size; + u8 event_type; + u8 data[0]; +}; + static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen) { static const char * const current_image_name[] = { @@ -69,6 +90,71 @@ exit: return ret; } +static int cros_ec_chardev_mkbp_event(struct notifier_block *nb, + unsigned long queued_during_suspend, + void *_notify) +{ + struct chardev_priv *priv = container_of(nb, struct chardev_priv, + notifier); + struct cros_ec_device *ec_dev = priv->ec_dev->ec_dev; + struct ec_event *event; + unsigned long event_bit = 1 << ec_dev->event_data.event_type; + int total_size = sizeof(*event) + ec_dev->event_size; + + if (!(event_bit & priv->event_mask) || + (priv->event_len + total_size) > CROS_MAX_EVENT_LEN) + return NOTIFY_DONE; + + event = kzalloc(total_size, GFP_KERNEL); + if (!event) + return NOTIFY_DONE; + + event->size = ec_dev->event_size; + event->event_type = ec_dev->event_data.event_type; + memcpy(event->data, &ec_dev->event_data.data, ec_dev->event_size); + + spin_lock(&priv->wait_event.lock); + list_add_tail(&event->node, &priv->events); + priv->event_len += total_size; + wake_up_locked(&priv->wait_event); + spin_unlock(&priv->wait_event.lock); + + return NOTIFY_OK; +} + +static struct ec_event *cros_ec_chardev_fetch_event(struct chardev_priv *priv, + bool fetch, bool block) +{ + struct ec_event *event; + int err; + + spin_lock(&priv->wait_event.lock); + if (!block && list_empty(&priv->events)) { + event = ERR_PTR(-EWOULDBLOCK); + goto out; + } + + if (!fetch) { + event = NULL; + goto out; + } + + err = wait_event_interruptible_locked(priv->wait_event, + !list_empty(&priv->events)); + if (err) { + event = ERR_PTR(err); + goto out; + } + + event = list_first_entry(&priv->events, struct ec_event, node); + list_del(&event->node); + priv->event_len -= sizeof(*event) + event->size; + +out: + spin_unlock(&priv->wait_event.lock); + return event; +} + /* * Device file ops */ @@ -76,11 +162,40 @@ 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); + struct chardev_priv *priv; + int ret; + + priv = kzalloc(sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; - filp->private_data = ec_dev; + priv->ec_dev = ec_dev; + filp->private_data = priv; + INIT_LIST_HEAD(&priv->events); + init_waitqueue_head(&priv->wait_event); nonseekable_open(inode, filp); - return 0; + priv->notifier.notifier_call = cros_ec_chardev_mkbp_event; + ret = blocking_notifier_chain_register(&ec_dev->ec_dev->event_notifier, + &priv->notifier); + if (ret) { + dev_err(ec_dev->dev, "failed to register event notifier\n"); + kfree(priv); + } + + return ret; +} + +static __poll_t cros_ec_chardev_poll(struct file *filp, poll_table *wait) +{ + struct chardev_priv *priv = filp->private_data; + + poll_wait(filp, &priv->wait_event, wait); + + if (list_empty(&priv->events)) + return 0; + + return EPOLLIN | EPOLLRDNORM; } static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer, @@ -88,14 +203,42 @@ static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer, { char msg[sizeof(struct ec_response_get_version) + sizeof(CROS_EC_DEV_VERSION)]; - struct cros_ec_dev *ec = filp->private_data; + struct chardev_priv *priv = filp->private_data; + struct cros_ec_dev *ec_dev = priv->ec_dev; size_t count; int ret; + if (priv->event_mask) { /* queued MKBP event */ + struct ec_event *event; + + event = cros_ec_chardev_fetch_event(priv, length != 0, + !(filp->f_flags & O_NONBLOCK)); + if (IS_ERR(event)) + return PTR_ERR(event); + /* + * length == 0 is special - no IO is done but we check + * for error conditions. + */ + if (length == 0) + return 0; + + /* The event is 1 byte of type plus the payload */ + count = min(length, event->size + 1); + ret = copy_to_user(buffer, &event->event_type, count); + kfree(event); + if (ret) /* the copy failed */ + return -EFAULT; + *offset = count; + return count; + } + + /* + * Legacy behavior if no event mask is defined + */ if (*offset != 0) return 0; - ret = ec_get_version(ec, msg, sizeof(msg)); + ret = ec_get_version(ec_dev, msg, sizeof(msg)); if (ret) return ret; @@ -108,6 +251,24 @@ static ssize_t cros_ec_chardev_read(struct file *filp, char __user *buffer, return count; } +static int cros_ec_chardev_release(struct inode *inode, struct file *filp) +{ + struct chardev_priv *priv = filp->private_data; + struct cros_ec_dev *ec_dev = priv->ec_dev; + struct ec_event *event, *e; + + blocking_notifier_chain_unregister(&ec_dev->ec_dev->event_notifier, + &priv->notifier); + + list_for_each_entry_safe(event, e, &priv->events, node) { + list_del(&event->node); + kfree(event); + } + kfree(priv); + + return 0; +} + /* * Ioctls */ @@ -181,7 +342,8 @@ static long cros_ec_chardev_ioctl_readmem(struct cros_ec_dev *ec, static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { - struct cros_ec_dev *ec = filp->private_data; + struct chardev_priv *priv = filp->private_data; + struct cros_ec_dev *ec = priv->ec_dev; if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC) return -ENOTTY; @@ -191,6 +353,9 @@ static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd, 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); + case CROS_EC_DEV_IOCEVENTMASK: + priv->event_mask = arg; + return 0; } return -ENOTTY; @@ -198,7 +363,9 @@ static long cros_ec_chardev_ioctl(struct file *filp, unsigned int cmd, static const struct file_operations chardev_fops = { .open = cros_ec_chardev_open, + .poll = cros_ec_chardev_poll, .read = cros_ec_chardev_read, + .release = cros_ec_chardev_release, .unlocked_ioctl = cros_ec_chardev_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = cros_ec_chardev_ioctl, |