Monitoring clients will want this feature on devices which do
not echo back the command for us. Make it a per-device-id
configurable item and disabled by default, as it represents
a behavioural change
This is preparing for supporting devices using other
protocols than AT commands. Such devices will typically not
echo back the received command.
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
---
This won't affect existing users. I was wondering how to enable
echo in a sane way. I did not want to that the tty route using
an ioctl... Although that is probably the only possible way
if configuring this is required per client?
For now it is a static device specific attribute. The assumption
is that QMI devices will have this on to enable monitoring complete
transactions from a read-only process, while AT based devices have
it turned off as they echo back commands themselves
drivers/usb/class/cdc-wdm.c | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index bd0cb5f..e0c17ff 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -31,6 +31,9 @@
#define DRIVER_AUTHOR "Oliver Neukum"
#define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
+/* attribute flags for device list */
+#define WDM_ATTR_ECHO 0x0001 /* device wants command echo */
+
static const struct usb_device_id wdm_ids[] = {
{
.match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
@@ -89,6 +92,8 @@ struct wdm_device {
loff_t pos; /* virtual "file position" mapped into ubuf */
loff_t valid; /* maintain boundary for packetized protocols! */
+
+ unsigned long attr; /* device specific attributes */
};
static struct usb_driver wdm_driver;
@@ -371,6 +376,16 @@ static ssize_t wdm_write
} else {
dev_dbg(&desc->intf->dev, "Tx URB has been submitted index=%d",
desc->orq->wIndex);
+ /*
+ * echo command if device attribute says so.
+ * Note: we don't update the file pointer on write, so
+ * this we will read this back ourselves as well
+ */
+ if (desc->attr & WDM_ATTR_ECHO) {
+ spin_lock_irq(&desc->iuspin);
+ wdm_copy_to_ubuf(desc, buf, count);
+ spin_unlock_irq(&desc->iuspin);
+ }
}
out:
usb_autopm_put_interface(desc->intf);
@@ -648,6 +663,10 @@ next_desc:
desc = kzalloc(sizeof(struct wdm_device), GFP_KERNEL);
if (!desc)
goto out;
+
+ /* save device specific attributes */
+ desc->attr = id->driver_info;
+
mutex_init(&desc->wlock);
spin_lock_init(&desc->iuspin);
init_waitqueue_head(&desc->wait);
--
1.7.8.3
--
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