On Tue, 2008-03-25 at 11:56 -0400, Jerry Van Baren wrote:
Joakim Tjernlund wrote:
On Tue, 2008-03-25 at 10:57 -0400, Ben Warren wrote:
Joakim Tjernlund wrote:
On Tue, 2008-03-25 at 10:22 -0400, Ben Warren wrote:
Stefan Roese wrote:
On Saturday 22 March 2008, Ben Warren wrote:
[snip]
Using Markus's idea, why not use a cpu (platform) specific *and* a board specific init function, both with an empty weak alias in the common eth.c code:
cpu_eth_init(bis); board_eth_init(bis);
I thought about this some more, and the problem is that cpu_eth_init() and board_eth_init() are mutually exclusive, with board_eth_init() having a higher priority. I think the following will work, but would appreciate some feedback.
int board_eth_init(bd_t *bis) __attribute(weak); int cpu_eth_init(bd_t *bis) __attribute(weak);
. . .
if (board_eth_init) board_eth_init(bis); else if (cpu_eth_init) cpu_eth_init(bis);
This gets rid of the pointless aliases and gives precedence to the board-specific initialization.
regards, Ben
I think you must enable full relocation, CONFIG_RELOC_FIXUP_WORKS, to make the "if (board_eth_init)" work. This is just a guess though.
Jocke
Nothing a little testing can't figure out.
thanks, Ben
You could do too: if (!board_eth_init(bis)) cpu_eth_init(bis);
Jocke
Per an earlier discussion on how weak functions are implemented, these are not equivalent. Functions marked "weak" *without* a weak implementation become NULL pointers. The code if (board_eth_init) board_eth_init(bis); else if (cpu_eth_init) cpu_eth_init(bis); uses that knowledge to see if the weak function board_eth_init() exists and then calls it if it does. If it doesn't exist, it sees if cpu_eth_init() exists and calls it if it does.
Your counter proposal assumes that a weak function board_eth_init() *does* exist and uses the returned result as the condition of executing cpu_eth_init() (assuming it also exists).
If you define a weak function that simply returns failure, your alternative is close, but still not the same because an overridden (*real*) board_eth_init() could return failure too, in which case it
Yes, see below for fix
will (probably erroneously) execute cpu_eth_init(). Beyond that, if cpu_eth_init() doesn't exist (doesn't have a default weak function defined), the call to it will go *SPLAT*.
HTH, gvb
All true, I was thinking that there would be default weak dummy versions of both board_eth_init() and cpu_eth_init() that would do the right thing. To address the weakness you spotted one would need three return values, something like: -1 fail 0 not impl. 1 success
Jocke