On Mon, Sep 02, 2019 at 06:08:48PM +0200, Enric Balletbo i Serra wrote: > Allow to poll on the cros_ec device to receive the MKBP events. > > The /dev/cros_[ec|fp|..] file operations now implements the poll > operation. The userspace can now receive specific MKBP events by doing > the > following: > - Open the /dev/cros_XX file. > - Call the CROS_EC_DEV_IOCEVENTMASK ioctl with the bitmap of the MKBP > events it wishes to receive as argument. > - Poll on the file descriptor. > - When it gets POLLIN, do a read on the file descriptor, the first > queued event will be returned (using the struct > ec_response_get_next_event format: one byte of event type, then > the payload). > > The read() operation returns at most one event even if there are several > queued, and it might be truncated if the buffer is smaller than the > event (but the caller should know the maximum size of the events it is > reading). > > read() used to return the EC version string, it still does it when no > event mask or an empty event is set for backward compatibility (despite > nobody really using this feature). > > This will be used, for example, by the userspace daemon to receive and > treat the EC_MKBP_EVENT_FINGERPRINT sent by the FP MCU. >
Acked-by: Andy Shevchenko <[email protected]> > Signed-off-by: Vincent Palatin <[email protected]> > Signed-off-by: Enric Balletbo i Serra <[email protected]> > --- > Note that this patch depends on the immutable branch [1] to apply > cleanly. > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/log/?h=ib-mfd-extcon-hid-i2c-iio-input-media-chrome-power-pwm-rtc-sound-5.4 > > > Changes in v2: > - Moved the code to the cros_ec_chardev driver. > > drivers/platform/chrome/cros_ec_chardev.c | 177 +++++++++++++++++- > include/linux/platform_data/cros_ec_chardev.h | 1 + > 2 files changed, 173 insertions(+), 5 deletions(-) > > diff --git a/drivers/platform/chrome/cros_ec_chardev.c > b/drivers/platform/chrome/cros_ec_chardev.c > index 08abd7e5c7bf..eabb1fe85688 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 @@ static int ec_get_version(struct cros_ec_dev *ec, char > *str, int maxlen) > return ret; > } > > +static int ec_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 *ec_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 = ec_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 = ec_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, > diff --git a/include/linux/platform_data/cros_ec_chardev.h > b/include/linux/platform_data/cros_ec_chardev.h > index 973b2615aa02..7de8faaf77df 100644 > --- a/include/linux/platform_data/cros_ec_chardev.h > +++ b/include/linux/platform_data/cros_ec_chardev.h > @@ -33,5 +33,6 @@ struct cros_ec_readmem { > #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) > +#define CROS_EC_DEV_IOCEVENTMASK _IO(CROS_EC_DEV_IOC, 2) > > #endif /* _CROS_EC_DEV_H_ */ > -- > 2.20.1 > -- With Best Regards, Andy Shevchenko
