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

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>

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index d103a1d4fb36713dac529bbc8703dd3023c6ab66..8f572b9f362555b55dc2e3cccfc5761140664616 100644 (file)
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -768,8 +768,10 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
        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)
@@ -874,6 +876,32 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
                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) {

diff --git a/drivers/net/usb/huawei_cdc_ncm.c b/drivers/net/usb/huawei_cdc_ncm.c
index 2680a65cd5e4fde5e333ef1ca1ff5d5ad4091222..63f28908afda78e05dcbcdd27e0a1a037f8b6fcb 100644 (file)
--- 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 usbnet *usbnet_dev,
         * 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;

diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h
index 021f7a88f52c929ec804d856a8f6541e1c4c6490..1a59699cf82a90bae208d478092a425d926f4d77 100644 (file)
--- 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)