usb: usbtmc: Add ioctl for generic requests on control

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/usbtmc.c b/drivers/usb/class/usbtmc.c
index 83ffa5a14c3dbbc53e8b964a4101e6e4a19c57a5..7e69bd05c6310fb108aac4fcf8168e756b7caa4c 100644 (file)
--- 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 @@ exit:
        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 729af2f861a4313a97243fdb7b11b56eff6e7545..5e12928ed1e50edae35582b91e486c0c4612bd8d 100644 (file)
--- 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)