Date: Sun, 28 Jun 2015 09:03:37
From: Enrico Mioso <mrkiko.rs@xxxxxxxxx>
To: Oliver Neukum <oneukum@xxxxxxxx>, linux-usb@xxxxxxxxxxxxxxx,
netdev@xxxxxxxxxxxxxxx
Cc: Enrico Mioso <mrkiko.rs@xxxxxxxxx>
Subject: [RFC PATCH] cdc_ncm: add support for moving NDP to end of frames
This patch adds support for moving the NDP (Network Data Pointer) part of
an NCM frame to the end of it. This allows newer Huawei devices to work with upstream Linux driver.
This functionality can be enabled by a cdc_ncm subdriver when binding to a
device. Hence this patch updates them.
This code works pretty well with an E3372 device I am testing it with.
The problem is - I observed my patch causing system failures when severe OOM
conditions are met. I am not sure the problem is cause by my code, but would like to hear from you.
Signed-off-by: Enrico Mioso <mrkiko.rs@xxxxxxxxx>
---
drivers/net/usb/cdc_mbim.c | 2 +-
drivers/net/usb/cdc_ncm.c | 51 ++++++++++++++++++++++++++++++++++++----
drivers/net/usb/huawei_cdc_ncm.c | 7 ++++--
include/linux/usb/cdc_ncm.h | 7 +++++-
4 files changed, 58 insertions(+), 9 deletions(-)
diff --git a/drivers/net/usb/cdc_mbim.c b/drivers/net/usb/cdc_mbim.c
index e4b7a47..efc18e0 100644
--- a/drivers/net/usb/cdc_mbim.c
+++ b/drivers/net/usb/cdc_mbim.c
@@ -158,7 +158,7 @@ static int cdc_mbim_bind(struct usbnet *dev, struct usb_interface *intf)
if (!cdc_ncm_comm_intf_is_mbim(intf->cur_altsetting))
goto err;
- ret = cdc_ncm_bind_common(dev, intf, data_altsetting);
+ ret = cdc_ncm_bind_common(dev, intf, data_altsetting, 0);
if (ret)
goto err;
diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 8067b8f..60b147f 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -684,10 +684,12 @@ static void cdc_ncm_free(struct cdc_ncm_ctx *ctx)
ctx->tx_curr_skb = NULL;
}
+ kfree(ctx->delayed_ndp16);
+
kfree(ctx);
}
-int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting)
+int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags)
{
const struct usb_cdc_union_desc *union_desc = NULL;
struct cdc_ncm_ctx *ctx;
@@ -855,6 +857,17 @@ advance:
/* finish setting up the device specific data */
cdc_ncm_setup(dev);
+ /* Device-specific flags */
+ ctx->drvflags = drvflags;
+
+ /* Allocate the delayed NDP if needed. */
+ if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
+ ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_ATOMIC);
+ if (!ctx->delayed_ndp16)
+ goto error2;
+ dev_info(&intf->dev, "NDP will be placed at end of frame for this device.");
+ }
+
/* override ethtool_ops */
dev->net->ethtool_ops = &cdc_ncm_ethtool_ops;
@@ -954,8 +967,11 @@ static int cdc_ncm_bind(struct usbnet *dev, struct usb_interface *intf)
if (cdc_ncm_select_altsetting(intf) != CDC_NCM_COMM_ALTSETTING_NCM)
return -ENODEV;
- /* The NCM data altsetting is fixed */
- ret = cdc_ncm_bind_common(dev, intf, CDC_NCM_DATA_ALTSETTING_NCM);
+ /* The NCM data altsetting is fixed, so we hard-coded it.
+ * Additionally, generic NCM devices are assumed to accept arbitrarily
+ * placed NDP.
+ */
+ ret = cdc_ncm_bind_common(dev, intf, CDC_NCM_DATA_ALTSETTING_NCM, 0);
/*
* We should get an event when network connection is "connected" or
@@ -986,6 +1002,14 @@ static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_
struct usb_cdc_ncm_nth16 *nth16 = (void *)skb->data;
size_t ndpoffset = le16_to_cpu(nth16->wNdpIndex);
+ /* If NDP should be moved to the end of the NCM package, we can't follow the
+ * NTH16 header as we would normally do. NDP isn't written to the SKB yet, and
+ * the wNdpIndex field in the header is actually not consistent with reality. It will be later.
+ */
+ if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)
+ if (ctx->delayed_ndp16->dwSignature == sign)
+ return ctx->delayed_ndp16;
+
/* follow the chain of NDPs, looking for a match */
while (ndpoffset) {
ndp16 = (struct usb_cdc_ncm_ndp16 *)(skb->data + ndpoffset);
@@ -995,7 +1019,8 @@ static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_
}
/* align new NDP */
- cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_max);
+ if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))
+ cdc_ncm_align_tail(skb, ctx->tx_ndp_modulus, 0, ctx->tx_max);
/* verify that there is room for the NDP and the datagram (reserve) */
if ((ctx->tx_max - skb->len - reserve) < ctx->max_ndp_size)
@@ -1008,7 +1033,12 @@ static struct usb_cdc_ncm_ndp16 *cdc_ncm_ndp(struct cdc_ncm_ctx *ctx, struct sk_
nth16->wNdpIndex = cpu_to_le16(skb->len);
/* push a new empty NDP */
- ndp16 = (struct usb_cdc_ncm_ndp16 *)memset(skb_put(skb, ctx->max_ndp_size), 0, ctx->max_ndp_size);
+ if (!(ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END)) {
+ ndp16 = (struct usb_cdc_ncm_ndp16 *)memset(skb_put(skb, ctx->max_ndp_size), 0, ctx->max_ndp_size);
+ } else {
+ ndp16 = ctx->delayed_ndp16;
+ }
+
ndp16->dwSignature = sign;
ndp16->wLength = cpu_to_le16(sizeof(struct usb_cdc_ncm_ndp16) + sizeof(struct usb_cdc_ncm_dpe16));
return ndp16;
@@ -1150,6 +1180,17 @@ cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign)
/* variables will be reset at next call */
}
+ /* If requested, put NDP at end of frame. */
+ if (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END) {
+ nth16 = (struct usb_cdc_ncm_nth16 *)skb_out->data;
+ cdc_ncm_align_tail(skb_out, ctx->tx_ndp_modulus, 0, ctx->tx_max);
+ nth16->wNdpIndex = cpu_to_le16(skb_out->len);
+ ndp16 = memcpy(skb_put(skb_out, ctx->max_ndp_size), ctx->delayed_ndp16, ctx->max_ndp_size);
+
+ /* Zero out delayed NDP - signature checking will naturally fail. */
+ memset(ctx->delayed_ndp16, 0, ctx->max_ndp_size);
+ }
+
/* If collected data size is less or equal ctx->min_tx_pkt
* bytes, we send buffers as it is. If we get more data, it
* would be more efficient for USB HS mobile device with DMA
diff --git a/drivers/net/usb/huawei_cdc_ncm.c b/drivers/net/usb/huawei_cdc_ncm.c
index 735f7da..2680a65 100644
--- a/drivers/net/usb/huawei_cdc_ncm.c
+++ b/drivers/net/usb/huawei_cdc_ncm.c
@@ -73,11 +73,14 @@ static int huawei_cdc_ncm_bind(struct usbnet *usbnet_dev,
struct usb_driver *subdriver = ERR_PTR(-ENODEV);
int ret = -ENODEV;
struct huawei_cdc_ncm_state *drvstate = (void *)&usbnet_dev->data;
+ int drvflags = 0;
/* altsetting should always be 1 for NCM devices - so we hard-coded
- * it here
+ * it here. Some huawei devices will need the NDP part of the NCM package to
+ * be at the end of the frame.
*/
- ret = cdc_ncm_bind_common(usbnet_dev, intf, 1);
+ drvflags |= CDC_NCM_FLAG_NDP_TO_END;
+ 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 7c9b484..1f6526c 100644
--- a/include/linux/usb/cdc_ncm.h
+++ b/include/linux/usb/cdc_ncm.h
@@ -80,6 +80,9 @@
#define CDC_NCM_TIMER_INTERVAL_MIN 5UL
#define CDC_NCM_TIMER_INTERVAL_MAX (U32_MAX / NSEC_PER_USEC)
+/* Driver flags */
+#define CDC_NCM_FLAG_NDP_TO_END 0x02 /* NDP is placed at end of frame */
+
#define cdc_ncm_comm_intf_is_mbim(x) ((x)->desc.bInterfaceSubClass == USB_CDC_SUBCLASS_MBIM && \
(x)->desc.bInterfaceProtocol == USB_CDC_PROTO_NONE)
#define cdc_ncm_data_intf_is_mbim(x) ((x)->desc.bInterfaceProtocol == USB_CDC_MBIM_PROTO_NTB)
@@ -103,9 +106,11 @@ struct cdc_ncm_ctx {
spinlock_t mtx;
atomic_t stop;
+ int drvflags;
u32 timer_interval;
u32 max_ndp_size;
+ struct usb_cdc_ncm_ndp16 *delayed_ndp16;
u32 tx_timer_pending;
u32 tx_curr_frame_num;
@@ -133,7 +138,7 @@ struct cdc_ncm_ctx {
};
u8 cdc_ncm_select_altsetting(struct usb_interface *intf);
-int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting);
+int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_altsetting, int drvflags);
void cdc_ncm_unbind(struct usbnet *dev, struct usb_interface *intf);
struct sk_buff *cdc_ncm_fill_tx_frame(struct usbnet *dev, struct sk_buff *skb, __le32 sign);
int cdc_ncm_rx_verify_nth16(struct cdc_ncm_ctx *ctx, struct sk_buff *skb_in);
--
2.4.4
