+!!! WARNING !!!
+
+This guide describes to the old way of doing things. No new Ethernet drivers
+should be implemented this way. All new drivers should be written against the
+U-Boot core driver model. See doc/driver-model/README.txt
+
-----------------------
Ethernet Driver Guide
-----------------------
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()
{
struct ape_priv *priv;
struct eth_device *dev;
+ struct mii_dev *bus;
priv = malloc(sizeof(*priv));
if (priv == NULL)
- return 1;
+ return -ENOMEM;
dev = malloc(sizeof(*dev));
if (dev == NULL) {
free(priv);
- return 1;
+ return -ENOMEM;
}
/* setup whatever private state you need */
memset(dev, 0, sizeof(*dev));
sprintf(dev->name, "APE");
- /* if your device has dedicated hardware storage for the
+ /*
+ * if your device has dedicated hardware storage for the
* MAC, read it and initialize dev->enetaddr with it
*/
ape_mac_read(dev->enetaddr);
dev->halt = ape_halt;
dev->send = ape_send;
dev->recv = ape_recv;
+ dev->write_hwaddr = ape_write_hwaddr;
eth_register(dev);
-#ifdef CONFIG_CMD_MII)
- miiphy_register(dev->name, ape_mii_read, ape_mii_write);
+#ifdef CONFIG_PHYLIB
+ bus = mdio_alloc();
+ if (!bus) {
+ free(priv);
+ free(dev);
+ return -ENOMEM;
+ }
+
+ bus->read = ape_mii_read;
+ bus->write = ape_mii_write;
+ mdio_register(bus);
#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 net_process_received_packet() function on it
+along with the packet length. The common code sets up packet buffers for you
+already in the .bss (net_rx_packets), so there should be no need to allocate your
+own. This doesn't mean you must use the net_rx_packets array however; you're
+free to call the net_process_received_packet() 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;
...
while (packets_are_available()) {
...
- length = ape_get_packet(&NetRxPackets[i]);
+ length = ape_get_packet(&net_rx_packets[i]);
...
- NetReceive(&NetRxPackets[i], length);
+ net_process_received_packet(&net_rx_packets[i], length);
...
if (++i >= PKTBUFSRX)
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...)
eth_halt()
dev->halt()
------------------------------
- CONFIG_MII / CONFIG_CMD_MII
------------------------------
+--------------------------------
+ CONFIG_PHYLIB / CONFIG_CMD_MII
+--------------------------------
If your device supports banging arbitrary values on the MII bus (pretty much
every device does), you should add support for the mii command. Doing so is
fairly trivial and makes debugging mii issues a lot easier at runtime.
After you have called eth_register() in your driver's register function, add
-a call to miiphy_register() like so:
-#if defined(CONFIG_MII) || defined(CONFIG_CMD_MII)
- miiphy_register(dev->name, mii_read, mii_write);
-#endif
+a call to mdio_alloc() and mdio_register() like so:
+ bus = mdio_alloc();
+ if (!bus) {
+ free(priv);
+ free(dev);
+ return -ENOMEM;
+ }
+
+ bus->read = ape_mii_read;
+ bus->write = ape_mii_write;
+ mdio_register(bus);
And then define the mii_read and mii_write functions if you haven't already.
Their syntax is straightforward:
- int mii_read(char *devname, uchar addr, uchar reg, ushort *val);
- int mii_write(char *devname, uchar addr, uchar reg, ushort val);
+ int mii_read(struct mii_dev *bus, int addr, int devad, int reg);
+ int mii_write(struct mii_dev *bus, int addr, int devad, int reg,
+ u16 val);
The read function should read the register 'reg' from the phy at address 'addr'
-and store the result in the pointer 'val'. The implementation for the write
-function should logically follow.
+and return the result to its caller. The implementation for the write function
+should logically follow.
projects / karo-tx-uboot.git / blobdiff