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-rw-r--r--drivers/platform/chrome/cros_ec_chardev.c177
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,