diff mbox series

[v6,01/22] usb: usbtmc: Add ioctl for generic requests on control

Message ID 20180912085112.4891-2-guido@kiener-muenchen.de (mailing list archive)
State New, archived
Headers show
Series usb: usbtmc: Changes needed for compatible IVI/VISA library | expand

Commit Message

Guido Kiener Sept. 12, 2018, 8:50 a.m. UTC
Add USBTMC_IOCTL_CTRL_REQUEST to send arbitrary requests on the
control pipe.  Used by specific applications of IVI Foundation,
Inc. to implement VISA API functions: viUsbControlIn/Out.

The maximum length of control request is set to 4k.

This ioctl does not support compatibility for 32 bit
applications running on 64 bit systems. However all other
convenient ioctls of the USBTMC driver can still be used in 32
bit applications as well. Note that 32 bit applications running
on 32 bit target systems are not affected by this limitation.

Signed-off-by: Guido Kiener <guido.kiener@rohde-schwarz.com>
Reviewed-by: Steve Bayless <steve_bayless@keysight.com>
---
 drivers/usb/class/usbtmc.c   | 69 ++++++++++++++++++++++++++++++++++++
 include/uapi/linux/usb/tmc.h | 15 ++++++++
 2 files changed, 84 insertions(+)

Comments

Greg Kroah-Hartman Sept. 20, 2018, 11 a.m. UTC | #1
On Wed, Sep 12, 2018 at 10:50:51AM +0200, Guido Kiener wrote:
> --- a/include/uapi/linux/usb/tmc.h
> +++ b/include/uapi/linux/usb/tmc.h
> @@ -4,6 +4,7 @@
>   * Copyright (C) 2008 Novell, Inc.
>   * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
>   * Copyright (C) 2015 Dave Penkler <dpenkler@gmail.com>
> + * Copyright (C) 2018 IVI Foundation, Inc.
>   *
>   * This file holds USB constants defined by the USB Device Class
>   * and USB488 Subclass Definitions for Test and Measurement devices
> @@ -40,6 +41,19 @@
>  #define USBTMC488_REQUEST_GOTO_LOCAL			161
>  #define USBTMC488_REQUEST_LOCAL_LOCKOUT			162
>  
> +struct usbtmc_request {
> +	__u8 bRequestType;
> +	__u8 bRequest;
> +	__u16 wValue;
> +	__u16 wIndex;
> +	__u16 wLength;
> +} __attribute__ ((packed));

This really is just 'struct usb_ctrlrequest', right?  That's already
defined in our uapi files.  Why not use that?

Bonus is, if you use that, you get the proper endian notation, which you
don't have here, which means this is broken on big endian machines :(

Try doing that, and fix up the endian issue.

thanks,

greg k-h
Greg Kroah-Hartman Sept. 20, 2018, 11:03 a.m. UTC | #2
On Thu, Sep 20, 2018 at 01:00:35PM +0200, Greg KH wrote:
> On Wed, Sep 12, 2018 at 10:50:51AM +0200, Guido Kiener wrote:
> > --- a/include/uapi/linux/usb/tmc.h
> > +++ b/include/uapi/linux/usb/tmc.h
> > @@ -4,6 +4,7 @@
> >   * Copyright (C) 2008 Novell, Inc.
> >   * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
> >   * Copyright (C) 2015 Dave Penkler <dpenkler@gmail.com>
> > + * Copyright (C) 2018 IVI Foundation, Inc.
> >   *
> >   * This file holds USB constants defined by the USB Device Class
> >   * and USB488 Subclass Definitions for Test and Measurement devices
> > @@ -40,6 +41,19 @@
> >  #define USBTMC488_REQUEST_GOTO_LOCAL			161
> >  #define USBTMC488_REQUEST_LOCAL_LOCKOUT			162
> >  
> > +struct usbtmc_request {
> > +	__u8 bRequestType;
> > +	__u8 bRequest;
> > +	__u16 wValue;
> > +	__u16 wIndex;
> > +	__u16 wLength;
> > +} __attribute__ ((packed));
> 
> This really is just 'struct usb_ctrlrequest', right?  That's already
> defined in our uapi files.  Why not use that?
> 
> Bonus is, if you use that, you get the proper endian notation, which you
> don't have here, which means this is broken on big endian machines :(
> 
> Try doing that, and fix up the endian issue.

Ah, nevermind, you are passing this to the hardware properly.  This
should be just fine, I'll take it as-is, sorry for the noise.

greg k-h
diff mbox series

Patch

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 83ffa5a14c3d..7e69bd05c631 100644
--- a/drivers/usb/class/usbtmc.c
+++ b/drivers/usb/class/usbtmc.c
@@ -5,6 +5,7 @@ 
  * Copyright (C) 2007 Stefan Kopp, Gechingen, Germany
  * Copyright (C) 2008 Novell, Inc.
  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (C) 2018 IVI Foundation, Inc.
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -36,6 +37,9 @@ 
 /* Default USB timeout (in milliseconds) */
 #define USBTMC_TIMEOUT		5000
 
+/* I/O buffer size used in generic read/write functions */
+#define USBTMC_BUFSIZE		(4096)
+
 /*
  * Maximum number of read cycles to empty bulk in endpoint during CLEAR and
  * ABORT_BULK_IN requests. Ends the loop if (for whatever reason) a short
@@ -1250,6 +1254,67 @@  static int usbtmc_ioctl_indicator_pulse(struct usbtmc_device_data *data)
 	return rv;
 }
 
+static int usbtmc_ioctl_request(struct usbtmc_device_data *data,
+				void __user *arg)
+{
+	struct device *dev = &data->intf->dev;
+	struct usbtmc_ctrlrequest request;
+	u8 *buffer = NULL;
+	int rv;
+	unsigned long res;
+
+	res = copy_from_user(&request, arg, sizeof(struct usbtmc_ctrlrequest));
+	if (res)
+		return -EFAULT;
+
+	buffer = kmalloc(request.req.wLength, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	if (request.req.wLength > USBTMC_BUFSIZE)
+		return -EMSGSIZE;
+
+	if (request.req.wLength) {
+		buffer = kmalloc(request.req.wLength, GFP_KERNEL);
+		if (!buffer)
+			return -ENOMEM;
+
+		if ((request.req.bRequestType & USB_DIR_IN) == 0) {
+			/* Send control data to device */
+			res = copy_from_user(buffer, request.data,
+					     request.req.wLength);
+			if (res) {
+				rv = -EFAULT;
+				goto exit;
+			}
+		}
+	}
+
+	rv = usb_control_msg(data->usb_dev,
+			usb_rcvctrlpipe(data->usb_dev, 0),
+			request.req.bRequest,
+			request.req.bRequestType,
+			request.req.wValue,
+			request.req.wIndex,
+			buffer, request.req.wLength, USB_CTRL_GET_TIMEOUT);
+
+	if (rv < 0) {
+		dev_err(dev, "%s failed %d\n", __func__, rv);
+		goto exit;
+	}
+
+	if (rv && (request.req.bRequestType & USB_DIR_IN)) {
+		/* Read control data from device */
+		res = copy_to_user(request.data, buffer, rv);
+		if (res)
+			rv = -EFAULT;
+	}
+
+ exit:
+	kfree(buffer);
+	return rv;
+}
+
 /*
  * Get the usb timeout value
  */
@@ -1366,6 +1431,10 @@  static long usbtmc_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 		retval = usbtmc_ioctl_abort_bulk_in(data);
 		break;
 
+	case USBTMC_IOCTL_CTRL_REQUEST:
+		retval = usbtmc_ioctl_request(data, (void __user *)arg);
+		break;
+
 	case USBTMC_IOCTL_GET_TIMEOUT:
 		retval = usbtmc_ioctl_get_timeout(file_data,
 						  (void __user *)arg);
diff --git a/include/uapi/linux/usb/tmc.h b/include/uapi/linux/usb/tmc.h
index 729af2f861a4..5e12928ed1e5 100644
--- a/include/uapi/linux/usb/tmc.h
+++ b/include/uapi/linux/usb/tmc.h
@@ -4,6 +4,7 @@ 
  * Copyright (C) 2008 Novell, Inc.
  * Copyright (C) 2008 Greg Kroah-Hartman <gregkh@suse.de>
  * Copyright (C) 2015 Dave Penkler <dpenkler@gmail.com>
+ * Copyright (C) 2018 IVI Foundation, Inc.
  *
  * This file holds USB constants defined by the USB Device Class
  * and USB488 Subclass Definitions for Test and Measurement devices
@@ -40,6 +41,19 @@ 
 #define USBTMC488_REQUEST_GOTO_LOCAL			161
 #define USBTMC488_REQUEST_LOCAL_LOCKOUT			162
 
+struct usbtmc_request {
+	__u8 bRequestType;
+	__u8 bRequest;
+	__u16 wValue;
+	__u16 wIndex;
+	__u16 wLength;
+} __attribute__ ((packed));
+
+struct usbtmc_ctrlrequest {
+	struct usbtmc_request req;
+	void __user *data; /* pointer to user space */
+} __attribute__ ((packed));
+
 struct usbtmc_termchar {
 	__u8 term_char;
 	__u8 term_char_enabled;
@@ -53,6 +67,7 @@  struct usbtmc_termchar {
 #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_CTRL_REQUEST	_IOWR(USBTMC_IOC_NR, 8, struct usbtmc_ctrlrequest)
 #define USBTMC_IOCTL_GET_TIMEOUT	_IOR(USBTMC_IOC_NR, 9, __u32)
 #define USBTMC_IOCTL_SET_TIMEOUT	_IOW(USBTMC_IOC_NR, 10, __u32)
 #define USBTMC_IOCTL_EOM_ENABLE	        _IOW(USBTMC_IOC_NR, 11, __u8)