On Tue, Jul 17, 2012 at 01:05:47PM +0800, Ram Pai wrote:
> On Tue, Jul 17, 2012 at 10:23:17AM +0800, Gavin Shan wrote:
> > The patch changes function pbus_size_io() and pbus_size_mem() to
> > do resource (I/O, memory and prefetchable memory) reassignment
> > based on the minimal alignments for the p2p bridge, which was
> > retrieved by function window_alignment().
> >
> > Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/pci/setup-bus.c | 13 +++++++++----
> > 1 files changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > index c0fb9da..a29483a 100644
> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -731,6 +731,7 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
> > struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
> > unsigned long size = 0, size0 = 0, size1 = 0;
> > resource_size_t children_add_size = 0;
> > + resource_size_t io_align;
> >
> > if (!b_res)
> > return;
> > @@ -756,13 +757,15 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
> > children_add_size += get_res_add_size(realloc_head, r);
> > }
> > }
> > +
> > + io_align = window_alignment(bus, IORESOURCE_IO);
>
> this should also be
> io_align = max(4096, window_alignment(bus, IORESOURCE_IO));
>
> right?
>
>
> > size0 = calculate_iosize(size, min_size, size1,
> > - resource_size(b_res), 4096);
> > + resource_size(b_res), io_align);
> > if (children_add_size > add_size)
> > add_size = children_add_size;
> > size1 = (!realloc_head || (realloc_head && !add_size)) ? size0 :
> > calculate_iosize(size, min_size, add_size + size1,
> > - resource_size(b_res), 4096);
> > + resource_size(b_res), io_align);
> > if (!size0 && !size1) {
> > if (b_res->start || b_res->end)
> > dev_info(&bus->self->dev, "disabling bridge window "
> > @@ -772,11 +775,11 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
> > return;
> > }
> > /* Alignment of the IO window is always 4K */
> > - b_res->start = 4096;
> > + b_res->start = io_align;
> > b_res->end = b_res->start + size0 - 1;
> > b_res->flags |= IORESOURCE_STARTALIGN;
> > if (size1 > size0 && realloc_head) {
> > - add_to_list(realloc_head, bus->self, b_res, size1-size0, 4096);
> > + add_to_list(realloc_head, bus->self, b_res, size1-size0, io_align);
> > dev_printk(KERN_DEBUG, &bus->self->dev, "bridge window "
> > "%pR to [bus %02x-%02x] add_size %lx\n", b_res,
> > bus->secondary, bus->subordinate, size1-size0);
> > @@ -875,6 +878,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> > min_align = align1 >> 1;
> > align += aligns[order];
> > }
> > +
> > + min_align = max(min_align, window_alignment(bus, type));
>
> 'type' can sometimes be (IORESOURCE_MEM | IORESOURCE_PREFETCH), which
> can lead to unpredictable results depending on how window_alignment()
> is implemented... Hence to be on the safer side I suggest
>
> min_align = max(min_align, window_alignment(bus, b_res->flags & mask));
While you are at it, can we move the min_align calculation into
a separate function?
Somewhat around the following patch
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 8fa2d4b..426c8ad6 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -762,6 +762,25 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
}
}
+static inline calculate_min_align(resource_size_t aligns *aligns, int max_order)
+{
+ resource_size_t align = 0;
+ resource_size_t min_align = 0;
+ int order;
+ for (order = 0; order <= max_order; order++) {
+ resource_size_t align1 = 1;
+
+ align1 <<= (order + 20);
+
+ if (!align)
+ min_align = align1;
+ else if (ALIGN(align + min_align, min_align) < align1)
+ min_align = align1 >> 1;
+ align += aligns[order];
+ }
+ return min_align;
+}
+
/**
* pbus_size_mem() - size the memory window of a given bus
*
@@ -841,19 +860,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
children_add_size += get_res_add_size(realloc_head, r);
}
}
- align = 0;
- min_align = 0;
- for (order = 0; order <= max_order; order++) {
- resource_size_t align1 = 1;
- align1 <<= (order + 20);
+ min_align = calculate_min_align(aligns, max_order);
- if (!align)
- min_align = align1;
- else if (ALIGN(align + min_align, min_align) < align1)
- min_align = align1 >> 1;
- align += aligns[order];
- }
size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align);
if (children_add_size > add_size)
add_size = children_add_size;
@@ -880,6 +889,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
return 1;
}
RP
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