From ac5ad93e92c3ffca4c7ba386aaa34244e27b7759 Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw@linux.vnet.ibm.com>
Date: Tue, 11 Sep 2012 16:59:45 -0600
Subject: [PATCH 1/5] 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 <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/setup-bus.c | 32 ++++++++++++++++++++++++++++++++
include/linux/pci.h | 2 ++
2 files changed, 34 insertions(+)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index fb506137aaee..896f06e3e793 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
*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index b8667e0548e0..2c755243eef2 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1064,6 +1064,8 @@ int pci_cfg_space_size_ext(struct pci_dev *dev);
int pci_cfg_space_size(struct pci_dev *dev);
unsigned char pci_bus_max_busnr(struct pci_bus *bus);
void pci_setup_bridge(struct pci_bus *bus);
+resource_size_t pcibios_window_alignment(struct pci_bus *bus,
+ unsigned long type);
#define PCI_VGA_STATE_CHANGE_BRIDGE (1 << 0)
#define PCI_VGA_STATE_CHANGE_DECODES (1 << 1)
From 462d93030628a598bc440dcd35c89fb7fc63f58c Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw@linux.vnet.ibm.com>
Date: Tue, 11 Sep 2012 16:59:46 -0600
Subject: [PATCH 2/5] 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 <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/setup-bus.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 896f06e3e793..a66cf0905a15 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;
From c121504e899c19f7e25b4894f616475073876361 Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw@linux.vnet.ibm.com>
Date: Tue, 11 Sep 2012 16:59:46 -0600
Subject: [PATCH 3/5] 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 <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/setup-bus.c | 36 +++++++++++++++++++++++-------------
1 file changed, 23 insertions(+), 13 deletions(-)
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index a66cf0905a15..1e808ca338f8 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)
From 4c2245bb5c9c6e9950ee8919b4462dfa77f7a28f Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw@linux.vnet.ibm.com>
Date: Tue, 11 Sep 2012 16:59:46 -0600
Subject: [PATCH 4/5] powerpc/PCI: Override pcibios_window_alignment()
This patch implements pcibios_window_alignment() so powerpc platforms can
force P2P bridge windows to be at larger alignments than the PCI spec
requires.
[bhelgaas: changelog]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
arch/powerpc/include/asm/machdep.h | 3 +++
arch/powerpc/kernel/pci-common.c | 20 ++++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 42ce570812c1..f7706d722b39 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -214,6 +214,9 @@ struct machdep_calls {
/* Called after scan and before resource survey */
void (*pcibios_fixup_phb)(struct pci_controller *hose);
+ /* Called during PCI resource reassignment */
+ resource_size_t (*pcibios_window_alignment)(struct pci_bus *, unsigned long type);
+
/* Called to shutdown machine specific hardware not already controlled
* by other drivers.
*/
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 2aa04f29e1de..43fea543d686 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -99,6 +99,26 @@ void pcibios_free_controller(struct pci_controller *phb)
kfree(phb);
}
+/*
+ * The function is used to return the minimal alignment
+ * for memory or I/O windows of the associated P2P bridge.
+ * By default, 4KiB alignment for I/O windows and 1MiB for
+ * memory windows.
+ */
+resource_size_t pcibios_window_alignment(struct pci_bus *bus,
+ unsigned long type)
+{
+ if (ppc_md.pcibios_window_alignment)
+ return ppc_md.pcibios_window_alignment(bus, type);
+
+ /*
+ * PCI core will figure out the default
+ * alignment: 4KiB for I/O and 1MiB for
+ * memory window.
+ */
+ return 1;
+}
+
static resource_size_t pcibios_io_size(const struct pci_controller *hose)
{
#ifdef CONFIG_PPC64
From 271fd03a3013b106ccc178d54219c1be0c9759b7 Mon Sep 17 00:00:00 2001
From: Gavin Shan <shangw@linux.vnet.ibm.com>
Date: Tue, 11 Sep 2012 16:59:47 -0600
Subject: [PATCH 5/5] powerpc/powernv: I/O and memory alignment for P2P bridges
The patch implements ppc_md.pcibios_window_alignment for powernv
platform so that the resource reassignment in PCI core will be
done according to the I/O and memory alignment returned from
powernv platform. The alignments returned from powernv platform
is closely depending on the scheme for PE segmenting. Besides,
the patch isn't useful for now, but the subsequent patches will
be working based on it.
[bhelgaas: use pci_pcie_type() since pci_dev.pcie_type was removed]
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
arch/powerpc/platforms/powernv/pci-ioda.c | 39 +++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index b46e1dadc882..0e7eccc0f88d 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1139,6 +1139,44 @@ static void __devinit pnv_pci_ioda_fixup_phb(struct pci_controller *hose)
}
}
+/*
+ * Returns the alignment for I/O or memory windows for P2P
+ * bridges. That actually depends on how PEs are segmented.
+ * For now, we return I/O or M32 segment size for PE sensitive
+ * P2P bridges. Otherwise, the default values (4KiB for I/O,
+ * 1MiB for memory) will be returned.
+ *
+ * The current PCI bus might be put into one PE, which was
+ * create against the parent PCI bridge. For that case, we
+ * needn't enlarge the alignment so that we can save some
+ * resources.
+ */
+static resource_size_t pnv_pci_window_alignment(struct pci_bus *bus,
+ unsigned long type)
+{
+ struct pci_dev *bridge;
+ struct pci_controller *hose = pci_bus_to_host(bus);
+ struct pnv_phb *phb = hose->private_data;
+ int num_pci_bridges = 0;
+
+ bridge = bus->self;
+ while (bridge) {
+ if (pci_pcie_type(bridge) == PCI_EXP_TYPE_PCI_BRIDGE) {
+ num_pci_bridges++;
+ if (num_pci_bridges >= 2)
+ return 1;
+ }
+
+ bridge = bridge->bus->self;
+ }
+
+ /* We need support prefetchable memory window later */
+ if (type & IORESOURCE_MEM)
+ return phb->ioda.m32_segsize;
+
+ return phb->ioda.io_segsize;
+}
+
/* Prevent enabling devices for which we couldn't properly
* assign a PE
*/
@@ -1306,6 +1344,7 @@ void __init pnv_pci_init_ioda1_phb(struct device_node *np)
*/
ppc_md.pcibios_fixup_phb = pnv_pci_ioda_fixup_phb;
ppc_md.pcibios_enable_device_hook = pnv_pci_enable_device_hook;
+ ppc_md.pcibios_window_alignment = pnv_pci_window_alignment;
pci_add_flags(PCI_PROBE_ONLY | PCI_REASSIGN_ALL_RSRC);
/* Reset IODA tables to a clean state */