From 739240a9f6ac4d4c841081029874b3521744e490 Mon Sep 17 00:00:00 2001 From: Guido Kiener Date: Wed, 12 Sep 2018 10:50:58 +0200 Subject: [PATCH] usb: usbtmc: Add ioctl USBTMC488_IOCTL_WAIT_SRQ Wait until an SRQ (service request) is received on the interrupt pipe or until the given period of time is expired. In contrast to the poll() function this ioctl does not return when other (a)synchronous I/O operations fail with EPOLLERR. Signed-off-by: Guido Kiener Reviewed-by: Steve Bayless Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/usbtmc.c | 57 ++++++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/usb/tmc.h | 1 + 2 files changed, 58 insertions(+) diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c index e4c80b4..e177bac 100644 --- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -130,6 +130,7 @@ struct usbtmc_file_data { u32 timeout; u8 srq_byte; atomic_t srq_asserted; + atomic_t closing; u8 eom_val; u8 term_char; @@ -193,6 +194,8 @@ static int usbtmc_open(struct inode *inode, struct file *filp) mutex_lock(&data->io_mutex); file_data->data = data; + atomic_set(&file_data->closing, 0); + /* copy default values from device settings */ file_data->timeout = USBTMC_TIMEOUT; file_data->term_char = data->TermChar; @@ -223,6 +226,7 @@ static int usbtmc_flush(struct file *file, fl_owner_t id) if (file_data == NULL) return -ENODEV; + atomic_set(&file_data->closing, 1); data = file_data->data; /* wait for io to stop */ @@ -576,6 +580,54 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data, return rv; } +static int usbtmc488_ioctl_wait_srq(struct usbtmc_file_data *file_data, + __u32 __user *arg) +{ + struct usbtmc_device_data *data = file_data->data; + struct device *dev = &data->intf->dev; + int rv; + u32 timeout; + unsigned long expire; + + if (!data->iin_ep_present) { + dev_dbg(dev, "no interrupt endpoint present\n"); + return -EFAULT; + } + + if (get_user(timeout, arg)) + return -EFAULT; + + expire = msecs_to_jiffies(timeout); + + mutex_unlock(&data->io_mutex); + + rv = wait_event_interruptible_timeout( + data->waitq, + atomic_read(&file_data->srq_asserted) != 0 || + atomic_read(&file_data->closing), + expire); + + mutex_lock(&data->io_mutex); + + /* Note! disconnect or close could be called in the meantime */ + if (atomic_read(&file_data->closing) || data->zombie) + rv = -ENODEV; + + if (rv < 0) { + /* dev can be invalid now! */ + pr_debug("%s - wait interrupted %d\n", __func__, rv); + return rv; + } + + if (rv == 0) { + dev_dbg(dev, "%s - wait timed out\n", __func__); + return -ETIMEDOUT; + } + + dev_dbg(dev, "%s - srq asserted\n", __func__); + return 0; +} + static int usbtmc488_ioctl_simple(struct usbtmc_device_data *data, void __user *arg, unsigned int cmd) { @@ -2142,6 +2194,11 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) retval = usbtmc488_ioctl_trigger(file_data); break; + case USBTMC488_IOCTL_WAIT_SRQ: + retval = usbtmc488_ioctl_wait_srq(file_data, + (__u32 __user *)arg); + break; + case USBTMC_IOCTL_CANCEL_IO: retval = usbtmc_ioctl_cancel_io(file_data); break; diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h index 5a69d9d..e228ad7 100644 --- a/include/uapi/linux/usb/tmc.h +++ b/include/uapi/linux/usb/tmc.h @@ -96,6 +96,7 @@ struct usbtmc_message { #define USBTMC488_IOCTL_GOTO_LOCAL _IO(USBTMC_IOC_NR, 20) #define USBTMC488_IOCTL_LOCAL_LOCKOUT _IO(USBTMC_IOC_NR, 21) #define USBTMC488_IOCTL_TRIGGER _IO(USBTMC_IOC_NR, 22) +#define USBTMC488_IOCTL_WAIT_SRQ _IOW(USBTMC_IOC_NR, 23, __u32) /* Cancel and cleanup asynchronous calls */ #define USBTMC_IOCTL_CANCEL_IO _IO(USBTMC_IOC_NR, 35) -- 2.7.4