Patch "cdc_ncm: Set NTB format again after altsetting switch for Huawei devices" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    cdc_ncm: Set NTB format again after altsetting switch for Huawei devices

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     cdc_ncm-set-ntb-format-again-after-altsetting-switch-for-huawei-devices.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 2b02c20ce0c28974b44e69a2e2f5ddc6a470ad6f Mon Sep 17 00:00:00 2001
From: Enrico Mioso <mrkiko.rs@gmail.com>
Date: Tue, 11 Jul 2017 17:21:52 +0200
Subject: cdc_ncm: Set NTB format again after altsetting switch for Huawei devices
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Enrico Mioso <mrkiko.rs@gmail.com>

commit 2b02c20ce0c28974b44e69a2e2f5ddc6a470ad6f upstream.

Some firmwares in Huawei E3372H devices have been observed to switch back
to NTB 32-bit format after altsetting switch.
This patch implements a driver flag to check for the device settings and
set NTB format to 16-bit again if needed.
The flag has been activated for devices controlled by the huawei_cdc_ncm.c
driver.

V1->V2:
- fixed broken error checks
- some corrections to the commit message
V2->V3:
- variable name changes, to clarify what's happening
- check (and possibly set) the NTB format later in the common bind code path

Signed-off-by: Enrico Mioso <mrkiko.rs@gmail.com>
Reported-and-tested-by: Christian Panton <christian@panton.org>
Reviewed-by: Bjørn Mork <bjorn@mork.no>
CC: Bjørn Mork <bjorn@mork.no>
CC: Christian Panton <christian@panton.org>
CC: linux-usb@vger.kernel.org
CC: netdev@vger.kernel.org
CC: Oliver Neukum <oliver@neukum.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Porto Rio <porto.rio@gmx.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/usb/cdc_ncm.c        |   28 ++++++++++++++++++++++++++++
 drivers/net/usb/huawei_cdc_ncm.c |    6 ++++++
 include/linux/usb/cdc_ncm.h      |    1 +
 3 files changed, 35 insertions(+)

--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -769,8 +769,10 @@ int cdc_ncm_bind_common(struct usbnet *d
 	u8 *buf;
 	int len;
 	int temp;
+	int err;
 	u8 iface_no;
 	struct usb_cdc_parsed_header hdr;
+	u16 curr_ntb_format;
 
 	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
 	if (!ctx)
@@ -875,6 +877,32 @@ int cdc_ncm_bind_common(struct usbnet *d
 		goto error2;
 	}
 
+	/*
+	 * Some Huawei devices have been observed to come out of reset in NDP32 mode.
+	 * Let's check if this is the case, and set the device to NDP16 mode again if
+	 * needed.
+	*/
+	if (ctx->drvflags & CDC_NCM_FLAG_RESET_NTB16) {
+		err = usbnet_read_cmd(dev, USB_CDC_GET_NTB_FORMAT,
+				      USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE,
+				      0, iface_no, &curr_ntb_format, 2);
+		if (err < 0) {
+			goto error2;
+		}
+
+		if (curr_ntb_format == USB_CDC_NCM_NTB32_FORMAT) {
+			dev_info(&intf->dev, "resetting NTB format to 16-bit");
+			err = usbnet_write_cmd(dev, USB_CDC_SET_NTB_FORMAT,
+					       USB_TYPE_CLASS | USB_DIR_OUT
+					       | USB_RECIP_INTERFACE,
+					       USB_CDC_NCM_NTB16_FORMAT,
+					       iface_no, NULL, 0);
+
+			if (err < 0)
+				goto error2;
+		}
+	}
+
 	cdc_ncm_find_endpoints(dev, ctx->data);
 	cdc_ncm_find_endpoints(dev, ctx->control);
 	if (!dev->in || !dev->out || !dev->status) {
--- a/drivers/net/usb/huawei_cdc_ncm.c
+++ b/drivers/net/usb/huawei_cdc_ncm.c
@@ -80,6 +80,12 @@ static int huawei_cdc_ncm_bind(struct us
 	 * be at the end of the frame.
 	 */
 	drvflags |= CDC_NCM_FLAG_NDP_TO_END;
+
+	/* Additionally, it has been reported that some Huawei E3372H devices, with
+	 * firmware version 21.318.01.00.541, come out of reset in NTB32 format mode, hence
+	 * needing to be set to the NTB16 one again.
+	 */
+	drvflags |= CDC_NCM_FLAG_RESET_NTB16;
 	ret = cdc_ncm_bind_common(usbnet_dev, intf, 1, drvflags);
 	if (ret)
 		goto err;
--- a/include/linux/usb/cdc_ncm.h
+++ b/include/linux/usb/cdc_ncm.h
@@ -83,6 +83,7 @@
 /* Driver flags */
 #define CDC_NCM_FLAG_NDP_TO_END			0x02	/* NDP is placed at end of frame */
 #define CDC_MBIM_FLAG_AVOID_ALTSETTING_TOGGLE	0x04	/* Avoid altsetting toggle during init */
+#define CDC_NCM_FLAG_RESET_NTB16 0x08	/* set NDP16 one more time after altsetting switch */
 
 #define cdc_ncm_comm_intf_is_mbim(x)  ((x)->desc.bInterfaceSubClass == USB_CDC_SUBCLASS_MBIM && \
 				       (x)->desc.bInterfaceProtocol == USB_CDC_PROTO_NONE)


Patches currently in stable-queue which might be from mrkiko.rs@gmail.com are

queue-4.9/cdc_ncm-set-ntb-format-again-after-altsetting-switch-for-huawei-devices.patch