On Thu, May 17, 2018 at 07:03:27PM +0200, Guido Kiener wrote:
> Add ioctls USBTMC_IOCTL_GET_TIMEOUT / USBTMC_IOCTL_SET_TIMEOUT to
> get/set I/O timeout for specific file handle.
>
> Different operations on an instrument can take different lengths of
> time thus it is important to be able to set the timeout slightly
> longer than the expected duration of each operation to optimise the
> responsiveness of the application. As the instrument may be shared by
> multiple applications the timeout should be settable on a per file
> descriptor basis.
>
> Tested-by: Dave Penkler <dpenkler@xxxxxxxxx>
> Reviewed-by: Steve Bayless <steve_bayless@xxxxxxxxxxxx>
> Signed-off-by: Dave Penkler <dpenkler@xxxxxxxxx>
> Signed-off-by: Guido Kiener <guido.kiener@xxxxxxxxxxxxxxxxx>
> ---
> drivers/usb/class/usbtmc.c | 58 +++++++++++++++++++++++++++++++++---
> include/uapi/linux/usb/tmc.h | 2 ++
> 2 files changed, 56 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
> index 5754354429d8..ad7872003420 100644
> --- a/drivers/usb/class/usbtmc.c
> +++ b/drivers/usb/class/usbtmc.c
> @@ -30,6 +30,8 @@
> */
> #define USBTMC_SIZE_IOBUFFER 2048
>
> +/* Minimum USB timeout (in milliseconds) */
> +#define USBTMC_MIN_TIMEOUT 100
> /* Default USB timeout (in milliseconds) */
> #define USBTMC_TIMEOUT 5000
>
> @@ -116,6 +118,7 @@ struct usbtmc_file_data {
> struct usbtmc_device_data *data;
> struct list_head file_elem;
>
> + u32 timeout;
> u8 srq_byte;
> atomic_t srq_asserted;
>
> @@ -163,6 +166,7 @@ static int usbtmc_open(struct inode *inode, struct file *filp)
> file_data->data = data;
>
> /* copy default values from device settings */
> + file_data->timeout = USBTMC_TIMEOUT;
> file_data->TermChar = data->TermChar;
> file_data->TermCharEnabled = data->TermCharEnabled;
> file_data->auto_abort = data->auto_abort;
> @@ -478,7 +482,7 @@ static int usbtmc488_ioctl_read_stb(struct usbtmc_file_data *file_data,
> rv = wait_event_interruptible_timeout(
> data->waitq,
> atomic_read(&data->iin_data_valid) != 0,
> - USBTMC_TIMEOUT);
> + file_data->timeout);
> if (rv < 0) {
> dev_dbg(dev, "wait interrupted %d\n", rv);
> goto exit;
> @@ -613,7 +617,8 @@ static int send_request_dev_dep_msg_in(struct usbtmc_file_data *file_data,
> retval = usb_bulk_msg(data->usb_dev,
> usb_sndbulkpipe(data->usb_dev,
> data->bulk_out),
> - buffer, USBTMC_HEADER_SIZE, &actual, USBTMC_TIMEOUT);
> + buffer, USBTMC_HEADER_SIZE,
> + &actual, file_data->timeout);
>
> /* Store bTag (in case we need to abort) */
> data->bTag_last_write = data->bTag;
> @@ -681,7 +686,7 @@ static ssize_t usbtmc_read(struct file *filp, char __user *buf,
> usb_rcvbulkpipe(data->usb_dev,
> data->bulk_in),
> buffer, USBTMC_SIZE_IOBUFFER, &actual,
> - USBTMC_TIMEOUT);
> + file_data->timeout);
>
> dev_dbg(dev, "usb_bulk_msg: retval(%u), done(%zu), remaining(%zu), actual(%d)\n", retval, done, remaining, actual);
>
> @@ -854,7 +859,7 @@ static ssize_t usbtmc_write(struct file *filp, const char __user *buf,
> usb_sndbulkpipe(data->usb_dev,
> data->bulk_out),
> buffer, n_bytes,
> - &actual, USBTMC_TIMEOUT);
> + &actual, file_data->timeout);
> if (retval != 0)
> break;
> n_bytes -= actual;
> @@ -1211,6 +1216,41 @@ static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
> return rv;
> }
>
> +/*
> + * Get the usb timeout value
> + */
> +static int usbtmc_ioctl_get_timeout(struct usbtmc_file_data *file_data,
> + void __user *arg)
> +{
> + __u32 timeout;
> +
> + timeout = file_data->timeout;
> +
> + return put_user(timeout, (__u32 __user *)arg);
> +}
> +
> +/*
> + * Set the usb timeout value
> + */
> +static int usbtmc_ioctl_set_timeout(struct usbtmc_file_data *file_data,
> + void __user *arg)
> +{
> + __u32 timeout;
> +
> + if (get_user(timeout, (__u32 __user *)arg))
> + return -EFAULT;
> +
> + /* Note that timeout = 0 means
> + * MAX_SCHEDULE_TIMEOUT in usb_control_msg
> + */
> + if (timeout < USBTMC_MIN_TIMEOUT)
> + return -EINVAL;
> +
> + file_data->timeout = timeout;
> +
> + return 0;
> +}
> +
> static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> {
> struct usbtmc_file_data *file_data;
> @@ -1251,6 +1291,16 @@ static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> retval = usbtmc_ioctl_abort_bulk_in(data);
> break;
>
> + case USBTMC_IOCTL_GET_TIMEOUT:
> + retval = usbtmc_ioctl_get_timeout(file_data,
> + (void __user *)arg);
> + break;
> +
> + case USBTMC_IOCTL_SET_TIMEOUT:
> + retval = usbtmc_ioctl_set_timeout(file_data,
> + (void __user *)arg);
> + break;
> +
> case USBTMC488_IOCTL_GET_CAPS:
> retval = copy_to_user((void __user *)arg,
> &data->usb488_caps,
> diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
> index 03f6adc8f35b..d6de192150f4 100644
> --- a/include/uapi/linux/usb/tmc.h
> +++ b/include/uapi/linux/usb/tmc.h
> @@ -46,6 +46,8 @@
> #define USBTMC_IOCTL_ABORT_BULK_IN _IO(USBTMC_IOC_NR, 4)
> #define USBTMC_IOCTL_CLEAR_OUT_HALT _IO(USBTMC_IOC_NR, 6)
> #define USBTMC_IOCTL_CLEAR_IN_HALT _IO(USBTMC_IOC_NR, 7)
> +#define USBTMC_IOCTL_GET_TIMEOUT _IOR(USBTMC_IOC_NR, 9, unsigned int)
> +#define USBTMC_IOCTL_SET_TIMEOUT _IOW(USBTMC_IOC_NR, 10, unsigned int)
What is the "size" of unsigned int in 32 vs. 64 bit kernels? Shouldn't
this be __u32?
thanks,
greg k-h
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