function which in turn takes care of initializing that particular instance.
Keep in mind that you should code the driver to avoid storing state in global
-data as someone might want to hook up two of the same devices to one board. If
-the state is maintained as global data, it makes using both of those devices
-impossible.
+data as someone might want to hook up two of the same devices to one board.
+Any such information that is specific to an interface should be stored in a
+private, driver-defined data structure and pointed to by eth->priv (see below).
So the call graph at this stage would look something like:
board_init()
dev->halt = ape_halt;
dev->send = ape_send;
dev->recv = ape_recv;
+ dev->write_hwaddr = ape_write_hwaddr;
eth_register(dev);
miiphy_register(dev->name, ape_mii_read, ape_mii_write);
#endif
- return 0;
+ return 1;
}
The exact arguments needed to initialize your device are up to you. If you
need to pass more/less arguments, that's fine. You should also add the
-prototype for your new register function to include/netdev.h. You might notice
-that many drivers seem to use xxx_initialize() rather than xxx_register().
-This is the old naming convention and should be avoided as it causes confusion
-with the driver-specific init function.
+prototype for your new register function to include/netdev.h.
+
+The return value for this function should be as follows:
+< 0 - failure (hardware failure, not probe failure)
+>=0 - number of interfaces detected
+
+You might notice that many drivers seem to use xxx_initialize() rather than
+xxx_register(). This is the old naming convention and should be avoided as it
+causes confusion with the driver-specific init function.
Other than locating the MAC address in dedicated hardware storage, you should
not touch the hardware in anyway. That step is handled in the driver-specific
-----------
Now that we've registered with the ethernet layer, we can start getting some
-real work done. You will need four functions:
+real work done. You will need five functions:
int ape_init(struct eth_device *dev, bd_t *bis);
int ape_send(struct eth_device *dev, volatile void *packet, int length);
int ape_recv(struct eth_device *dev);
int ape_halt(struct eth_device *dev);
+ int ape_write_hwaddr(struct eth_device *dev);
The init function checks the hardware (probing/identifying) and gets it ready
for send/recv operations. You often do things here such as resetting the MAC
The recv function should process packets as long as the hardware has them
readily available before returning. i.e. you should drain the hardware fifo.
-The common code sets up packet buffers for you already (NetRxPackets), so there
-is no need to allocate your own. For each packet you receive, you should call
-the NetReceive() function on it with the packet length. So the pseudo code
-here would look something like:
+For each packet you receive, you should call the NetReceive() function on it
+along with the packet length. The common code sets up packet buffers for you
+already in the .bss (NetRxPackets), so there should be no need to allocate your
+own. This doesn't mean you must use the NetRxPackets array however; you're
+free to call the NetReceive() function with any buffer you wish. So the pseudo
+code here would look something like:
int ape_recv(struct eth_device *dev)
{
int length, i = 0;
}
The halt function should turn off / disable the hardware and place it back in
-its reset state.
+its reset state. It can be called at any time (before any call to the related
+init function), so make sure it can handle this sort of thing.
+
+The write_hwaddr function should program the MAC address stored in dev->enetaddr
+into the Ethernet controller.
So the call graph at this stage would look something like:
some net operation (ping / tftp / whatever...)
projects / kernel / u-boot.git / blobdiff