UM0851 datasheet(50/245 Pages) STMICROELECTRONICS

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Communication device drivers

UM0851

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Doc ID 16604 Rev 2

configured should be sufficient to handle the excess traffic, otherwise there is a possibility of

retransmissions or packet losses.

Packet transmission

Whenever the kernel needs to transmit a data packet, it calls the driver's hard_start_xmit()

method to put the data on an outgoing queue. The socket buffer passed to hard_start_xmit()

contains the physical packet as it should appear on the media, complete with the

transmission-level headers. The interface does not need to modify the data being

transmitted. skb->data points to the packet being transmitted, and skb->len is its length in

octets.

The transmission function in the SPEAr driver initializes DMA Descriptors to point to the

relevant socket buffer to be transmitted. As soon as the transmission is complete, the TX

completed interrupt is received, where a transmission tasklet is scheduled for freeing up the

socket buffers being used for transfers, and reinitializing some of the parameters of the DMA

descriptors.

4.1.5

GMAC driver usage

Usage of ifconfig command

The "ifconfig" command allows the operating system to setup the network interfaces and the

user to view information about the configured interfaces.

●

To configure the network IP address:

#ifconfig eth0 192.168.1.1 netmask 255.255.255.0

#ifconfig eth0

eth0

Link encap:Ethernet

HWaddr 08:00:17:0b:92:10

inet addr:192.168.1.1

Bcast:192.168.1.255 Mask:255.255.255.0

UP BROADCAST RUNNING MULTICAST

MTU:1500

Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:32

RX bytes:0 (0.0 B)

TX bytes:0 (0.0 B)

●

To configure the MTU size:

ifconfig eth0 mtu <size>

/* If the user sets the mtu size as 4000 and then gives following command */

#ifconfig eth0

eth0

Link encap:Ethernet

HWaddr 08:00:17:0b:92:10

inet addr:192.168.1.1

Bcast:192.168.1.255

Mask:255.255.255.0

UP BROADCAST RUNNING MULTICAST

MTU:4000

Metric:1

RX packets:0 errors:0 dropped:0 overruns:0 frame:0

TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:32

RX bytes:0 (0.0 B)

TX bytes:0 (0.0 B)

Note:

The maximum MTU size for SPEAr600 is 4000 and the for SPEAr300 is 9000

●

To shutdown the interface and reactivate it:

UM0851 Datasheet(PDF) 50 Page - STMicroelectronics

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