Comtrol eCos - Manual (Page 601)

Chapter 46. Generic Ethernet Device Driver
Generic Ethernet API
This file provides a simple description of how to write a low-level, hardware dependent ethernet driver.
There is a high-level driver (which is only code — with no state of its own) that is part of the stack. There will be
one or more low-level drivers tied to the actual network hardware. Each of these drivers contains one or more driver
instances. The intent is that the low-level drivers know nothing of the details of the stack that will be using them.
Thus, the same driver can be used by the eCos supported TCP/IP stack, RedBoot, or any other, with no changes.
A driver instance is contained within a struct eth_drv_sc:
struct eth_hwr_funs {
// Initialize hardware (including startup)
void (*start)(struct eth_drv_sc *sc,
unsigned char *enaddr,
int flags);
// Shut down hardware
void (*stop)(struct eth_drv_sc *sc);
// Device control (ioctl pass-thru)
int (*control)(struct eth_drv_sc *sc,
unsigned long key,
void *data,
int data_length);
// Query - can a packet be sent?
int (*can_send)(struct eth_drv_sc *sc);
// Send a packet of data
void (*send)(struct eth_drv_sc *sc,
struct eth_drv_sg *sg_list,
int sg_len,
int total_len,
unsigned long key);
// Receive [unload] a packet of data
void (*recv)(struct eth_drv_sc *sc,
struct eth_drv_sg *sg_list,
int sg_len);
// Deliver data to/from device from/to stack memory space
// (moves lots of memcpy()s out of DSRs into thread)
void (*deliver)(struct eth_drv_sc *sc);
// Poll for interrupts/device service
void (*poll)(struct eth_drv_sc *sc);
// Get interrupt information from hardware driver
int (*int_vector)(struct eth_drv_sc *sc);
// Logical driver interface
struct eth_drv_funs *eth_drv, *eth_drv_old;
};
struct eth_drv_sc {
struct eth_hwr_funs *funs;
void *driver_private;
const char *dev_name;
int state;
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