On Friday 21 February 2014 14:47:08 Thomas Petazzoni wrote:

quoted

So I'd say this looks like a very promising approach. 

Indeed. However, I don't think this approach solves the entire problem,
for two reasons:

 *) For small BARs that are not power-of-two sized, we may not want to
    consume two windows, but instead consume a little bit more address
    space. Using two windows to map a 96 KB BAR would be a waste of
    windows: using a single 128 KB window is much more efficient.

definitely.
 

 *) I don't know if the algorithm to split the BAR into multiple
    windows is going to be trivial.

The easiest solution would be to special case 'size is between
128MB+1 and 192MB' if that turns out to be the most interesting
case. It's easy enough to make the second window smaller than 64MB
if we want.

If we want things to be a little fancier, we could use:

	switch (size) {
		case (SZ_32M+1) ... (SZ_32M+SZ_16M):
			size2 = size - SZ_32M;
			size -= SZ_32M;
			break;
		case (SZ_64M+1) ... (SZ_64M+SZ_32M):
			size2 = size - SZ_64M;
			size -= SZ_64M;
			break;
		case (SZ_128M+1) ... (SZ_128M+SZ_64M):
			size2 = size - SZ_128M;
			size -= SZ_128M;
			break;
	};


	Arnd