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net: cdc_ncm: refactoring cdc_ncm_setup
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Rewriting the "set max datagram" part of dc_ncm_setup to
separate the selection and validatation of the size from
the code which optionally informs the device of this
value.  This ensures that we use the correct value
regardless of device support for the get and set commands.

Removing some of the many indent levels while doing this
to make the code more readable.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Bjørn Mork authored and David S. Miller committed Nov 2, 2013
1 parent 6dd13e8 commit 47175e5
Showing 1 changed file with 44 additions and 64 deletions.
108 changes: 44 additions & 64 deletions drivers/net/usb/cdc_ncm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -76,8 +76,7 @@ static u8 cdc_ncm_setup(struct usbnet *dev)
int err;
int eth_hlen;
u16 ntb_fmt_supported;
u32 min_dgram_size;
u32 min_hdr_size;
__le16 max_datagram_size;

iface_no = ctx->control->cur_altsetting->desc.bInterfaceNumber;

Expand All @@ -101,20 +100,29 @@ static u8 cdc_ncm_setup(struct usbnet *dev)
ctx->tx_max_datagrams = le16_to_cpu(ncm_parm.wNtbOutMaxDatagrams);
ntb_fmt_supported = le16_to_cpu(ncm_parm.bmNtbFormatsSupported);

eth_hlen = ETH_HLEN;
min_dgram_size = CDC_NCM_MIN_DATAGRAM_SIZE;
min_hdr_size = CDC_NCM_MIN_HDR_SIZE;
if (ctx->mbim_desc != NULL) {
flags = ctx->mbim_desc->bmNetworkCapabilities;
/* there are some minor differences in NCM and MBIM defaults */
if (cdc_ncm_comm_intf_is_mbim(ctx->control->cur_altsetting)) {
if (!ctx->mbim_desc)
return -EINVAL;
eth_hlen = 0;
min_dgram_size = CDC_MBIM_MIN_DATAGRAM_SIZE;
min_hdr_size = 0;
} else if (ctx->func_desc != NULL) {
flags = ctx->func_desc->bmNetworkCapabilities;
flags = ctx->mbim_desc->bmNetworkCapabilities;
ctx->max_datagram_size = le16_to_cpu(ctx->mbim_desc->wMaxSegmentSize);
if (ctx->max_datagram_size < CDC_MBIM_MIN_DATAGRAM_SIZE)
ctx->max_datagram_size = CDC_MBIM_MIN_DATAGRAM_SIZE;
} else {
flags = 0;
if (!ctx->func_desc)
return -EINVAL;
eth_hlen = ETH_HLEN;
flags = ctx->func_desc->bmNetworkCapabilities;
ctx->max_datagram_size = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
if (ctx->max_datagram_size < CDC_NCM_MIN_DATAGRAM_SIZE)
ctx->max_datagram_size = CDC_NCM_MIN_DATAGRAM_SIZE;
}

/* common absolute max for NCM and MBIM */
if (ctx->max_datagram_size > CDC_NCM_MAX_DATAGRAM_SIZE)
ctx->max_datagram_size = CDC_NCM_MAX_DATAGRAM_SIZE;

dev_dbg(&dev->intf->dev,
"dwNtbInMaxSize=%u dwNtbOutMaxSize=%u wNdpOutPayloadRemainder=%u wNdpOutDivisor=%u wNdpOutAlignment=%u wNtbOutMaxDatagrams=%u flags=0x%x\n",
ctx->rx_max, ctx->tx_max, ctx->tx_remainder, ctx->tx_modulus,
Expand Down Expand Up @@ -151,8 +159,7 @@ static u8 cdc_ncm_setup(struct usbnet *dev)
}

/* verify maximum size of transmitted NTB in bytes */
if ((ctx->tx_max <
(min_hdr_size + min_dgram_size)) ||
if ((ctx->tx_max < (CDC_NCM_MIN_HDR_SIZE + ctx->max_datagram_size)) ||
(ctx->tx_max > CDC_NCM_NTB_MAX_SIZE_TX)) {
dev_dbg(&dev->intf->dev, "Using default maximum transmit length=%d\n",
CDC_NCM_NTB_MAX_SIZE_TX);
Expand Down Expand Up @@ -229,60 +236,33 @@ static u8 cdc_ncm_setup(struct usbnet *dev)
dev_dbg(&dev->intf->dev, "Setting NTB format to 16-bit failed\n");
}

ctx->max_datagram_size = min_dgram_size;
/* inform the device about the selected Max Datagram Size */
if (!(flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE))
goto out;

/* set Max Datagram Size (MTU) */
if (flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE) {
__le16 max_datagram_size;
u16 eth_max_sz;
if (ctx->ether_desc != NULL)
eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
else if (ctx->mbim_desc != NULL)
eth_max_sz = le16_to_cpu(ctx->mbim_desc->wMaxSegmentSize);
else
goto max_dgram_err;

err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE,
USB_TYPE_CLASS | USB_DIR_IN
| USB_RECIP_INTERFACE,
0, iface_no, &max_datagram_size, 2);
if (err < 0) {
dev_dbg(&dev->intf->dev, "GET_MAX_DATAGRAM_SIZE failed, use size=%u\n",
min_dgram_size);
} else {
ctx->max_datagram_size =
le16_to_cpu(max_datagram_size);
/* Check Eth descriptor value */
if (ctx->max_datagram_size > eth_max_sz)
ctx->max_datagram_size = eth_max_sz;

if (ctx->max_datagram_size > CDC_NCM_MAX_DATAGRAM_SIZE)
ctx->max_datagram_size = CDC_NCM_MAX_DATAGRAM_SIZE;

if (ctx->max_datagram_size < min_dgram_size)
ctx->max_datagram_size = min_dgram_size;

/* if value changed, update device */
if (ctx->max_datagram_size !=
le16_to_cpu(max_datagram_size)) {
max_datagram_size = cpu_to_le16(ctx->max_datagram_size);
err = usbnet_write_cmd(dev,
USB_CDC_SET_MAX_DATAGRAM_SIZE,
USB_TYPE_CLASS | USB_DIR_OUT
| USB_RECIP_INTERFACE,
0,
iface_no, &max_datagram_size,
2);
if (err < 0)
dev_dbg(&dev->intf->dev, "SET_MAX_DGRAM_SIZE failed\n");
}
}
/* read current mtu value from device */
err = usbnet_read_cmd(dev, USB_CDC_GET_MAX_DATAGRAM_SIZE,
USB_TYPE_CLASS | USB_DIR_IN | USB_RECIP_INTERFACE,
0, iface_no, &max_datagram_size, 2);
if (err < 0) {
dev_dbg(&dev->intf->dev, "GET_MAX_DATAGRAM_SIZE failed\n");
goto out;
}

max_dgram_err:
if (dev->net->mtu != (ctx->max_datagram_size - eth_hlen))
dev->net->mtu = ctx->max_datagram_size - eth_hlen;
if (le16_to_cpu(max_datagram_size) == ctx->max_datagram_size)
goto out;

max_datagram_size = cpu_to_le16(ctx->max_datagram_size);
err = usbnet_write_cmd(dev, USB_CDC_SET_MAX_DATAGRAM_SIZE,
USB_TYPE_CLASS | USB_DIR_OUT | USB_RECIP_INTERFACE,
0, iface_no, &max_datagram_size, 2);
if (err < 0)
dev_dbg(&dev->intf->dev, "SET_MAX_DATAGRAM_SIZE failed\n");

out:
/* set MTU to max supported by the device if necessary */
if (dev->net->mtu > ctx->max_datagram_size - eth_hlen)
dev->net->mtu = ctx->max_datagram_size - eth_hlen;
return 0;
}

Expand Down

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