From ac5ad93e92c3ffca4c7ba386aaa34244e27b7759 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Tue, 11 Sep 2012 16:59:45 -0600 Subject: PCI: Add weak pcibios_window_alignment() interface This patch implements a weak function to return the default I/O or memory window alignment for a P2P bridge. By default, I/O windows are aligned to 4KiB or 1KiB and memory windows are aligned to 4MiB. Some platforms, e.g., powernv, have special alignment requirements and can override pcibios_window_alignment(). [bhelgaas: changelog] Signed-off-by: Gavin Shan Signed-off-by: Bjorn Helgaas --- drivers/pci/setup-bus.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'drivers') diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index fb506137aae..896f06e3e79 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -697,6 +697,38 @@ static resource_size_t calculate_memsize(resource_size_t size, return size; } +resource_size_t __weak pcibios_window_alignment(struct pci_bus *bus, + unsigned long type) +{ + return 1; +} + +#define PCI_P2P_DEFAULT_MEM_ALIGN 0x100000 /* 1MiB */ +#define PCI_P2P_DEFAULT_IO_ALIGN 0x1000 /* 4KiB */ +#define PCI_P2P_DEFAULT_IO_ALIGN_1K 0x400 /* 1KiB */ + +static resource_size_t window_alignment(struct pci_bus *bus, + unsigned long type) +{ + resource_size_t align = 1, arch_align; + + if (type & IORESOURCE_MEM) + align = PCI_P2P_DEFAULT_MEM_ALIGN; + else if (type & IORESOURCE_IO) { + /* + * Per spec, I/O windows are 4K-aligned, but some + * bridges have an extension to support 1K alignment. + */ + if (bus->self->io_window_1k) + align = PCI_P2P_DEFAULT_IO_ALIGN_1K; + else + align = PCI_P2P_DEFAULT_IO_ALIGN; + } + + arch_align = pcibios_window_alignment(bus, type); + return max(align, arch_align); +} + /** * pbus_size_io() - size the io window of a given bus * -- cgit v1.2.3-70-g09d2 From 462d93030628a598bc440dcd35c89fb7fc63f58c Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Tue, 11 Sep 2012 16:59:46 -0600 Subject: PCI: Align P2P windows using pcibios_window_alignment() This patch changes pbus_size_io() and pbus_size_mem() to do window (I/O, memory and prefetchable memory) reassignment based on the minimal alignments for the P2P bridge, which was retrieved by window_alignment(). [bhelgaas: changelog] Signed-off-by: Gavin Shan Signed-off-by: Bjorn Helgaas --- drivers/pci/setup-bus.c | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) (limited to 'drivers') diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 896f06e3e79..a66cf0905a1 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -749,17 +749,12 @@ 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; + resource_size_t min_align, io_align, 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; + io_align = min_align = window_alignment(bus, IORESOURCE_IO); list_for_each_entry(dev, &bus->devices, bus_list) { int i; @@ -786,8 +781,8 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, } } - if (min_align > 4096) - min_align = 4096; + if (min_align > io_align) + min_align = io_align; size0 = calculate_iosize(size, min_size, size1, resource_size(b_res), min_align); @@ -909,6 +904,8 @@ 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, b_res->flags & mask)); size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align); if (children_add_size > add_size) add_size = children_add_size; -- cgit v1.2.3-70-g09d2 From c121504e899c19f7e25b4894f616475073876361 Mon Sep 17 00:00:00 2001 From: Gavin Shan Date: Tue, 11 Sep 2012 16:59:46 -0600 Subject: PCI: Refactor pbus_size_mem() The original idea comes from Ram Pai. This patch puts the chunk of code for calculating the minimal alignment of memory window into a separate inline function. Signed-off-by: Gavin Shan Signed-off-by: Bjorn Helgaas --- drivers/pci/setup-bus.c | 36 +++++++++++++++++++++++------------- 1 file changed, 23 insertions(+), 13 deletions(-) (limited to 'drivers') diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index a66cf0905a1..1e808ca338f 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -812,6 +812,28 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, } } +static inline resource_size_t calculate_mem_align(resource_size_t *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 * @@ -891,20 +913,8 @@ 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); - - if (!align) - min_align = align1; - else if (ALIGN(align + min_align, min_align) < align1) - min_align = align1 >> 1; - align += aligns[order]; - } + min_align = calculate_mem_align(aligns, max_order); min_align = max(min_align, window_alignment(bus, b_res->flags & mask)); size0 = calculate_memsize(size, min_size, 0, resource_size(b_res), min_align); if (children_add_size > add_size) -- cgit v1.2.3-70-g09d2