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net: qmi_wwan: MDM9x30 specific power management 

MDM9x30 based modems appear to go into a deeper sleep when
suspended without "Remote Wakeup" enabled.  The QMI interface
will not respond unless a "set DTR" control request is sent
on resume. The effect is similar to a QMI_CTL SYNC request,
resetting (some of) the firmware state.

We allow userspace sessions to span multiple character device
open/close sequences.  This means that userspace can depend
on firmware state while both the netdev and the character
device are closed.  We have disabled "needs_remote_wakeup" at
this point to allow devices without remote wakeup support to
be auto-suspended.

To make sure the MDM9x30 keeps firmware state, we need to
keep "needs_remote_wakeup" always set. We also need to
issue a "set DTR" request to enable the QMI interface.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Bjørn Mork 2015-12-03 19:24:18 +01:00 committed by David S. Miller
parent 43dd7a8bb6
commit 9372514979
1 changed files with 38 additions and 0 deletions
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38
drivers/net/usb/qmi_wwan.c
View File

@ -223,6 +223,20 @@ static int qmi_wwan_register_subdriver(struct usbnet *dev)
return rv;
}
/* Send CDC SetControlLineState request, setting or clearing the DTR.
* "Required for Autoconnect and 9x30 to wake up" according to the
* GobiNet driver. The requirement has been verified on an MDM9230
* based Sierra Wireless MC7455
*/
static int qmi_wwan_change_dtr(struct usbnet *dev, bool on)
{
u8 intf = dev->intf->cur_altsetting->desc.bInterfaceNumber;
return usbnet_write_cmd(dev, USB_CDC_REQ_SET_CONTROL_LINE_STATE,
USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
on ? 0x01 : 0x00, intf, NULL, 0);
}
static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
{
int status = -1;
@ -280,6 +294,24 @@ static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)
usb_driver_release_interface(driver, info->data);
}
/* disabling remote wakeup on MDM9x30 devices has the same
* effect as clearing DTR. The device will not respond to QMI
* requests until we set DTR again. This is similar to a
* QMI_CTL SYNC request, clearing a lot of firmware state
* including the client ID allocations.
*
* Our usage model allows a session to span multiple
* open/close events, so we must prevent the firmware from
* clearing out state the clients might need.
*
* MDM9x30 is the first QMI chipset with USB3 support. Abuse
* this fact to enable the quirk.
*/
if (le16_to_cpu(dev->udev->descriptor.bcdUSB) >= 0x0201) {
qmi_wwan_manage_power(dev, 1);
qmi_wwan_change_dtr(dev, true);
}
/* Never use the same address on both ends of the link, even if the
* buggy firmware told us to. Or, if device is assigned the well-known
* buggy firmware MAC address, replace it with a random address,
@ -307,6 +339,12 @@ static void qmi_wwan_unbind(struct usbnet *dev, struct usb_interface *intf)
if (info->subdriver && info->subdriver->disconnect)
info->subdriver->disconnect(info->control);
/* disable MDM9x30 quirk */
if (le16_to_cpu(dev->udev->descriptor.bcdUSB) >= 0x0201) {
qmi_wwan_change_dtr(dev, false);
qmi_wwan_manage_power(dev, 0);
}
/* allow user to unbind using either control or data */
if (intf == info->control)
other = info->data;