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authorYinghai Lu <yinghai@kernel.org>2012-07-09 19:55:29 -0600
committerBjorn Helgaas <bhelgaas@google.com>2012-07-09 19:55:29 -0600
commitfd591341102ba5eb9e517d3889e7566fa45e021e (patch)
treee4e658bac28fe3626c9507a459d648d14a007b5e /drivers/pci
parent2b28ae1912e5ce5bb0527e352ae6ff04e76183d1 (diff)
downloadlinux-fd591341102ba5eb9e517d3889e7566fa45e021e.tar.bz2
PCI: support sizing P2P bridge I/O windows with 1K granularity
Some bridges support I/O windows with 1K alignment, not just the 4K alignment defined by the PCI spec. For example, see the IOBL_ADR register and the EN1K bit in the CNF register in the Intel 82870P2 (P64H2). This patch adds support for sizing the window in 1K increments based on the requirements of downstream devices. [bhelgaas: changelog, comment] Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/setup-bus.c28
1 files changed, 22 insertions, 6 deletions
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index dad5425f1f09..eb0293e23e48 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -706,7 +706,7 @@ static resource_size_t calculate_memsize(resource_size_t size,
* @realloc_head : track the additional io window on this list
*
* Sizing the IO windows of the PCI-PCI bridge is trivial,
- * since these windows have 4K granularity and the IO ranges
+ * since these windows have 1K or 4K granularity and the IO ranges
* of non-bridge PCI devices are limited to 256 bytes.
* We must be careful with the ISA aliasing though.
*/
@@ -717,10 +717,17 @@ 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 min_align = 4096, align;
if (!b_res)
return;
+ /*
+ * Per spec, I/O windows are 4K-aligned, but some bridges have an
+ * extension to support 1K alignment.
+ */
+ if (bus->self->io_window_1k)
+ min_align = 1024;
list_for_each_entry(dev, &bus->devices, bus_list) {
int i;
@@ -738,17 +745,25 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
else
size1 += r_size;
+ align = pci_resource_alignment(dev, r);
+ if (align > min_align)
+ min_align = align;
+
if (realloc_head)
children_add_size += get_res_add_size(realloc_head, r);
}
}
+
+ if (min_align > 4096)
+ min_align = 4096;
+
size0 = calculate_iosize(size, min_size, size1,
- resource_size(b_res), 4096);
+ resource_size(b_res), min_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), min_align);
if (!size0 && !size1) {
if (b_res->start || b_res->end)
dev_info(&bus->self->dev, "disabling bridge window "
@@ -757,12 +772,13 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size,
b_res->flags = 0;
return;
}
- /* Alignment of the IO window is always 4K */
- b_res->start = 4096;
+
+ b_res->start = min_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,
+ min_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);