RE: Freebios2 recovery progress... pci64 mem optimization

[YhLu]

Eric,

In northbridge.c

Another typo error

/* If so place the one with the most stringent
alignment first */
                if (mem2->align > mem1->align) {
                        struct resource *tmp;
                        tmp = mem1;
                        mem1 = mem2;
                        mem2 = mem1;
                }
                /* Now place the memory as high up as it will go */
                mem2->base = resource_max(mem2);
                mem1->limit = mem2->base - 1;
                mem1->base = resource_max(mem1);

---->
    	  /* If so place the one with the most stringent alignment
first */
                if (mem2->align > mem1->align) {
                        struct resource *tmp;
                        tmp = mem1;
                        mem1 = mem2;
                        mem2 = tmp;
                }
                /* Now place the memory as high up as it will go */
                mem2->base = resource_max(mem2);
                mem1->limit = mem2->base - 1;
                mem1->base = resource_max(mem1);

Another question is

Should do align big allocation at first or align small first.

It seems you should do align big allocation.

Align big first

base1: 0xd0000000 limit1: 0xfebfffff size: 0x18800000 align: 28
base2: 0xec000000 limit2: 0xfebfffff size: 0x06b00000 align: 26
base1: 0xd8000000 limit1: 0xdfffffff size: 0x06b00000 align: 26
base2: 0xe0000000 limit2: 0xfebfffff size: 0x18800000 align: 28
PCI_DOMAIN: 0000 00 <- [0x0000001000 - 0x0000005fff] io
PCI_DOMAIN: 0000 01 <- [0x00e0000000 - 0x00f87fffff] prefmem
PCI_DOMAIN: 0000 02 <- [0x00d8000000 - 0x00deafffff] mem

Align small first
base1: 0xd0000000 limit1: 0xfebfffff size: 0x18800000 align: 28
base2: 0xec000000 limit2: 0xfebfffff size: 0x06b00000 align: 26
base1: 0xd0000000 limit1: 0xf7ffffff size: 0x18800000 align: 28
base2: 0xf8000000 limit2: 0xfebfffff size: 0x06b00000 align: 26
PCI_DOMAIN: 0000 00 <- [0x0000001000 - 0x0000005fff] io
PCI_DOMAIN: 0000 01 <- [0x00d0000000 - 0x00e87fffff] prefmem
PCI_DOMAIN: 0000 02 <- [0x00f8000000 - 0x00feafffff] mem

Freebios2 recovery progress... pci64 mem optimization

YhLu  writes:
> Eric,
>
> In northbridge.c
>
> Another typo error

Thanks. My test case obviously does not include a 32bit prefetchable memory
resource.
> Another question is
>
> Should do align big allocation at first or align small first.
>
> It seems you should do align big allocation.

Hmm.

What has generally proved to be a good solution.
Is to allocate the resources with the largest alignment at
the lowest addresses, and the resources with the less strict
alignment at later addresses.  
So I think we are in agreement about what works well.

I don't think it matters which order you perform the allocation
so long as the larger alignments come at the lower addresses in
memory.

Right now this is a first pass and it does ok, but it has
all sorts of issues.  I believe what really needs to happen
is that these resources become transparent/subtractive
and that compute_allocate_resource be taught how to do a better
job with limits.

That should also help with the case where one bridge can do something
better than another bridge.

The current strategy of reducing the limit of the parent resource actually
falls down when we hit pnp I/O resources that are only 12 bit.

I need to be fresh before I fix the general problem though.

Eric