[PATCH Resend v7 0/8] minimal alignment for p2p bars

[PATCH Resend v7 0/8] minimal alignment for p2p bars

[Gavin Shan]

v1 -> v2:
	* Shorten the varaible names so that they looks more short.
	* Changelog adjustment so that they looks more meaningful.

v2 -> v3:
	* Rebase to 3.5.RC4

v3 -> v4:
	* Merge Yinghai's patches.

v3 -> v4:
	* Split patch for easy review.
	* Add function to retrieve the minimal alignment of p2p bridge. 

v4 -> v5:
	* Rebase to 3.5.RC7
	* Introduce weak function pcibios_window_alignment() to retrieve
	  I/O and memory alignment for P2P bridges.
	* Introduce pcibios_window_alignment() for ppc to override the
	  PCI function.
	* Add ppc_md.pcibios_window_alignment() for specific platform like
	  powernv can override ppc's pcibios_window_alignment().

v5 -> v6:
	* Refactor pcibios_window_alignment() so the platform-specific
	  implementation needn't return the default alignment according
	  to Bjorn's suggestion.
	* Simplify pbus_size_mem() according to Bjorn's suggestion: Just
	  check the platform required alignment at very end and adjust
	  the "min_align" if necessary.

v6 -> v7:
	* Change "type" to "b_res->flags & mask" while retrieving the
	  minimal alignment for memory window according to Ram's suggestion.
	* Refactor pbus_size_mem() according to Ram's suggestion.
	* ppc_md.pcibios_window_alignment returns 1 for those PCI bridges
	  behind PCI bridges so that PCI core will use default alignment
	  values.

Lu Yinghai(3):
  pci: change variable name for find_pci_host_bridge
  pci: argument pci_bus for find_pci_host_bridge
  pci: fiddle with conversion of pci and CPU address

Gavin Shan(5)
  pci: weak function returns alignment
  pci: resource assignment based on p2p alignment
  pci: refactor function pbus_size_mem
  ppc/pci: override pcibios_window_alignment
  ppc/pnv: I/O and memory alignment for p2p bridges

-----

arch/powerpc/include/asm/machdep.h        |    3 +
arch/powerpc/kernel/pci-common.c          |   20 ++++++++
arch/powerpc/platforms/powernv/pci-ioda.c |   38 ++++++++++++++++
drivers/pci/host-bridge.c                 |   35 ++++++++++-----
drivers/pci/setup-bus.c                   |   68 ++++++++++++++++++++++-------
include/linux/pci.h                       |    7 +++-
6 files changed, 142 insertions(+), 29 deletions(-)

Thanks,
Gavin

[PATCH 1/8] pci: change variable name for find_pci_host_bridge

[Gavin Shan]

The patch changes the variable name for function find_pci_host_bridge()
so that it looks more meaningful. More specificly, the "bus" has been
replaced with "root_bus".

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/host-bridge.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index a68dc61..c19776a 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -22,9 +22,9 @@ static struct pci_bus *find_pci_root_bus(struct pci_dev *dev)
 
 static struct pci_host_bridge *find_pci_host_bridge(struct pci_dev *dev)
 {
-	struct pci_bus *bus = find_pci_root_bus(dev);
+	struct pci_bus *root_bus = find_pci_root_bus(dev);
 
-	return to_pci_host_bridge(bus->bridge);
+	return to_pci_host_bridge(root_bus->bridge);
 }
 
 void pci_set_host_bridge_release(struct pci_host_bridge *bridge,
-- 
1.7.5.4

[PATCH 2/8] pci: argument pci_bus for find_pci_host_bridge

[Gavin Shan]

The patch changes the argument of find_pci_host_bridge() to pci_bus.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/host-bridge.c |   13 +++++--------
 1 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index c19776a..fc16357 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -9,20 +9,17 @@
 
 #include "pci.h"
 
-static struct pci_bus *find_pci_root_bus(struct pci_dev *dev)
+static struct pci_bus *find_pci_root_bus(struct pci_bus *bus)
 {
-	struct pci_bus *bus;
-
-	bus = dev->bus;
 	while (bus->parent)
 		bus = bus->parent;
 
 	return bus;
 }
 
-static struct pci_host_bridge *find_pci_host_bridge(struct pci_dev *dev)
+static struct pci_host_bridge *find_pci_host_bridge(struct pci_bus *bus)
 {
-	struct pci_bus *root_bus = find_pci_root_bus(dev);
+	struct pci_bus *root_bus = find_pci_root_bus(bus);
 
 	return to_pci_host_bridge(root_bus->bridge);
 }
@@ -43,7 +40,7 @@ static bool resource_contains(struct resource *res1, struct resource *res2)
 void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
 			     struct resource *res)
 {
-	struct pci_host_bridge *bridge = find_pci_host_bridge(dev);
+	struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
 	struct pci_host_bridge_window *window;
 	resource_size_t offset = 0;
 
@@ -71,7 +68,7 @@ static bool region_contains(struct pci_bus_region *region1,
 void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 			     struct pci_bus_region *region)
 {
-	struct pci_host_bridge *bridge = find_pci_host_bridge(dev);
+	struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
 	struct pci_host_bridge_window *window;
 	resource_size_t offset = 0;
 
-- 
1.7.5.4

[PATCH 3/8] fiddle with conversion of pci and CPU address

[Gavin Shan]

The patch fiddles with the those functions used to do conversion
between PCI and CPU address. More specificly, 2 functions are
involved: pcibios_bus_to_resource() and pcibios_resource_to_bus()

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/host-bridge.c |   24 +++++++++++++++++++-----
 include/linux/pci.h       |    5 ++++-
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
index fc16357..abcf053 100644
--- a/drivers/pci/host-bridge.c
+++ b/drivers/pci/host-bridge.c
@@ -37,10 +37,10 @@ static bool resource_contains(struct resource *res1, struct resource *res2)
 	return res1->start <= res2->start && res1->end >= res2->end;
 }
 
-void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
-			     struct resource *res)
+void __pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
+			       struct resource *res)
 {
-	struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
+	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
 	struct pci_host_bridge_window *window;
 	resource_size_t offset = 0;
 
@@ -57,6 +57,13 @@ void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
 	region->start = res->start - offset;
 	region->end = res->end - offset;
 }
+
+void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
+			     struct resource *res)
+{
+	__pcibios_resource_to_bus(dev->bus, region, res);
+}
+
 EXPORT_SYMBOL(pcibios_resource_to_bus);
 
 static bool region_contains(struct pci_bus_region *region1,
@@ -65,10 +72,10 @@ static bool region_contains(struct pci_bus_region *region1,
 	return region1->start <= region2->start && region1->end >= region2->end;
 }
 
-void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
+void __pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
 			     struct pci_bus_region *region)
 {
-	struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
+	struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
 	struct pci_host_bridge_window *window;
 	resource_size_t offset = 0;
 
@@ -90,4 +97,11 @@ void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 	res->start = region->start + offset;
 	res->end = region->end + offset;
 }
+
+void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
+			     struct pci_bus_region *region)
+{
+	__pcibios_bus_to_resource(dev->bus, res, region);
+}
+
 EXPORT_SYMBOL(pcibios_bus_to_resource);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index d8c379d..9acea4b 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -654,9 +654,12 @@ void pcibios_update_irq(struct pci_dev *, int irq);
 void pci_fixup_cardbus(struct pci_bus *);
 
 /* Generic PCI functions used internally */
-
+void __pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
+				struct resource *res);
 void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
 			     struct resource *res);
+void __pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
+			       struct pci_bus_region *region);
 void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
 			     struct pci_bus_region *region);
 void pcibios_scan_specific_bus(int busn);
-- 
1.7.5.4

Re: [PATCH 3/8] fiddle with conversion of pci and CPU address

[Wei Yang]

I am not sure why you want to rename those functions.

BTW, i think you change the parameter of find_pci_host_bridge() in patch 2/8.

So if I just apply 2/8, it will fail the compilation, i think.


2012/7/25 Gavin Shan <shangw@linux.vnet.ibm.com>:
> The patch fiddles with the those functions used to do conversion
> between PCI and CPU address. More specificly, 2 functions are
> involved: pcibios_bus_to_resource() and pcibios_resource_to_bus()
>
> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
> ---
>  drivers/pci/host-bridge.c |   24 +++++++++++++++++++-----
>  include/linux/pci.h       |    5 ++++-
>  2 files changed, 23 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/pci/host-bridge.c b/drivers/pci/host-bridge.c
> index fc16357..abcf053 100644
> --- a/drivers/pci/host-bridge.c
> +++ b/drivers/pci/host-bridge.c
> @@ -37,10 +37,10 @@ static bool resource_contains(struct resource *res1, struct resource *res2)
>         return res1->start <= res2->start && res1->end >= res2->end;
>  }
>
> -void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
> -                            struct resource *res)
> +void __pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
> +                              struct resource *res)
>  {
> -       struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
> +       struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
>         struct pci_host_bridge_window *window;
>         resource_size_t offset = 0;
>
> @@ -57,6 +57,13 @@ void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
>         region->start = res->start - offset;
>         region->end = res->end - offset;
>  }
> +
> +void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
> +                            struct resource *res)
> +{
> +       __pcibios_resource_to_bus(dev->bus, region, res);
> +}
> +
>  EXPORT_SYMBOL(pcibios_resource_to_bus);
>
>  static bool region_contains(struct pci_bus_region *region1,
> @@ -65,10 +72,10 @@ static bool region_contains(struct pci_bus_region *region1,
>         return region1->start <= region2->start && region1->end >= region2->end;
>  }
>
> -void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
> +void __pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
>                              struct pci_bus_region *region)
>  {
> -       struct pci_host_bridge *bridge = find_pci_host_bridge(dev->bus);
> +       struct pci_host_bridge *bridge = find_pci_host_bridge(bus);
>         struct pci_host_bridge_window *window;
>         resource_size_t offset = 0;
>
> @@ -90,4 +97,11 @@ void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
>         res->start = region->start + offset;
>         res->end = region->end + offset;
>  }
> +
> +void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
> +                            struct pci_bus_region *region)
> +{
> +       __pcibios_bus_to_resource(dev->bus, res, region);
> +}
> +
>  EXPORT_SYMBOL(pcibios_bus_to_resource);
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index d8c379d..9acea4b 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -654,9 +654,12 @@ void pcibios_update_irq(struct pci_dev *, int irq);
>  void pci_fixup_cardbus(struct pci_bus *);
>
>  /* Generic PCI functions used internally */
> -
> +void __pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
> +                               struct resource *res);
>  void pcibios_resource_to_bus(struct pci_dev *dev, struct pci_bus_region *region,
>                              struct resource *res);
> +void __pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
> +                              struct pci_bus_region *region);
>  void pcibios_bus_to_resource(struct pci_dev *dev, struct resource *res,
>                              struct pci_bus_region *region);
>  void pcibios_scan_specific_bus(int busn);
> --
> 1.7.5.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Richard Yang
Help You, Help Me

[PATCH 4/8] pci: weak function returns alignment

[Gavin Shan]

The patch implements the weak function to return the default I/O
or memory alignment for P2P bridge. Currently, I/O window has 4KiB
alignment and memory window is 4MiB aligned by default. On the other
hand, those platforms (e.g. powernv) that have special requirements
on the alignment could override the function by themselves.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/setup-bus.c |   21 +++++++++++++++++++++
 include/linux/pci.h     |    2 ++
 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 8fa2d4b..c0fb9da 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -690,6 +690,27 @@ 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;
+}
+
+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 = 1024*1024;	/* 1MiB */
+	else if (type & IORESOURCE_IO)
+		align = 4*1024;		/* 4KiB */
+
+	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 9acea4b..34ff2bb 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -988,6 +988,8 @@ 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)
-- 
1.7.5.4

Re: [PATCH 4/8] pci: weak function returns alignment

[Wei Yang]

2012/7/25 Gavin Shan <shangw@linux.vnet.ibm.com>:
> The patch implements the weak function to return the default I/O
> or memory alignment for P2P bridge. Currently, I/O window has 4KiB
> alignment and memory window is 4MiB aligned by default. On the other
> hand, those platforms (e.g. powernv) that have special requirements
> on the alignment could override the function by themselves.
>
> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
> ---
>  drivers/pci/setup-bus.c |   21 +++++++++++++++++++++
>  include/linux/pci.h     |    2 ++
>  2 files changed, 23 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> index 8fa2d4b..c0fb9da 100644
> --- a/drivers/pci/setup-bus.c
> +++ b/drivers/pci/setup-bus.c
> @@ -690,6 +690,27 @@ 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;
> +}
> +
> +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 = 1024*1024;      /* 1MiB */
> +       else if (type & IORESOURCE_IO)
> +               align = 4*1024;         /* 4KiB */
> +

If this is a constant, could we use define a macro?
So we don't use to calculate the value every time.
Maybe some compile will be smart enough to optimize this,
still think it is better to give a result.

> +       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 9acea4b..34ff2bb 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -988,6 +988,8 @@ 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)
> --
> 1.7.5.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Richard Yang
Help You, Help Me

[PATCH 5/8] pci: resource assignment based on p2p alignment

[Gavin Shan]

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@linux.vnet.ibm.com>
---
 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..ca885ff 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);
 	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, 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;
-- 
1.7.5.4

[PATCH 6/8] pci: refactor function pbus_size_mem

[Gavin Shan]

The original idea comes from Ram Pai. The patch puts the chunk of
code for calculating the minimal alignment of memory window into
separate inline function.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/setup-bus.c |   36 +++++++++++++++++++++++-------------
 1 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index ca885ff..bdb7bd5 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -786,6 +786,28 @@ 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
  *
@@ -865,20 +887,8 @@ 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)
-- 
1.7.5.4

[PATCH 7/8] ppc/pci: override pcibios_window_alignment

[Gavin Shan]

Function pcibios_window_alignment() has been implemented as "weak"
in PCI core to return the default alignment of I/O and memory windows
for the associated p2p bridge. The patch adds same function to
override the weak one so that the default alignment could be changed
for those platforms (e.g. powernv).

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/machdep.h |    3 +++
 arch/powerpc/kernel/pci-common.c   |   20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index 42ce570..f7706d7 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 8e78e93..776df07 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
-- 
1.7.5.4

[PATCH 8/8] ppc/pnv: I/O and memory alignment for p2p bridges

[Gavin Shan]

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.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 arch/powerpc/platforms/powernv/pci-ioda.c |   38 +++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index fbdd74d..159bce5 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1139,6 +1139,43 @@ 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.
+ */
+static resource_size_t pnv_pci_window_alignment(struct pci_bus *bus,
+						unsigned long type)
+{
+	struct pci_dev *dev = bus->self;
+	struct pci_controller *hose = pci_bus_to_host(bus);
+	struct pnv_phb *phb = hose->private_data;
+
+	/* PCI root bus will be assigned with segment size */
+	if (!dev)
+		goto out;
+
+	/*
+	 * If the parent bridge is PCI bridge, we will return
+	 * the default values
+	 */
+	dev = dev->bus->self;
+	if (!dev)
+		goto out;
+	if (dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+		return 1;
+	}
+
+out:
+	/* 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 +1343,7 @@ 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 */
-- 
1.7.5.4

Re: [PATCH 8/8] ppc/pnv: I/O and memory alignment for p2p bridges

[Wei Yang]

2012/7/25 Gavin Shan <shangw@linux.vnet.ibm.com>:
> 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.
>
> Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
> ---
>  arch/powerpc/platforms/powernv/pci-ioda.c |   38 +++++++++++++++++++++++++++++
>  1 files changed, 38 insertions(+), 0 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index fbdd74d..159bce5 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1139,6 +1139,43 @@ 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.
> + */
> +static resource_size_t pnv_pci_window_alignment(struct pci_bus *bus,
> +                                               unsigned long type)
> +{
> +       struct pci_dev *dev = bus->self;
> +       struct pci_controller *hose = pci_bus_to_host(bus);
> +       struct pnv_phb *phb = hose->private_data;
> +
> +       /* PCI root bus will be assigned with segment size */
> +       if (!dev)
> +               goto out;
> +

there is a function, pci_is_root_bus() which is introduced in
79af72d7, to check whether
this bus is a root bus or not.

> +       /*
> +        * If the parent bridge is PCI bridge, we will return
> +        * the default values
> +        */
> +       dev = dev->bus->self;
> +       if (!dev)
> +               goto out;
> +       if (dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
> +               return 1;
> +       }
> +
> +out:
> +       /* 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 +1343,7 @@ 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 */
> --
> 1.7.5.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html



-- 
Richard Yang
Help You, Help Me

[PATCH V8 0/8] Minimal alignment for p2p bars

[Gavin Shan]

v1 -> v2:
	* Shorten the varaible names so that they looks more short.
        * Changelog adjustment so that they looks more meaningful.

v2 -> v3:
        * Rebase to 3.5.RC4

v3 -> v4:
        * Merge Yinghai's patches.

v3 -> v4:
        * Split patch for easy review.
        * Add function to retrieve the minimal alignment of p2p bridge.

v4 -> v5:
        * Rebase to 3.5.RC7
        * Introduce weak function pcibios_window_alignment() to retrieve
          I/O and memory alignment for P2P bridges.
        * Introduce pcibios_window_alignment() for ppc to override the
          PCI function.
        * Add ppc_md.pcibios_window_alignment() for specific platform like
          powernv can override ppc's pcibios_window_alignment().

v5 -> v6:
        * Refactor pcibios_window_alignment() so the platform-specific
          implementation needn't return the default alignment according
          to Bjorn's suggestion.
        * Simplify pbus_size_mem() according to Bjorn's suggestion: Just
          check the platform required alignment at very end and adjust
          the "min_align" if necessary.

v6 -> v7:
        * Change "type" to "b_res->flags & mask" while retrieving the
          minimal alignment for memory window according to Ram's suggestion.
        * Refactor pbus_size_mem() according to Ram's suggestion.
        * ppc_md.pcibios_window_alignment returns 1 for those PCI bridges
          behind PCI bridges so that PCI core will use default alignment
          values.

v7 -> v8:
	* Rebase to 3.6.RC2, which starts to use "struct resource" to represent
	  the range of PCI bus numbers that specific p2p bridge covers.
	* Define macros for the default alignment of P2P bars according to
	  Richard's comments.

Lu Yinghai(3):
  pci: change variable name for find_pci_host_bridge
  pci: argument pci_bus for find_pci_host_bridge
  pci: fiddle with conversion of pci and CPU address

Gavin Shan(5)
  pci: weak function returns alignment
  pci: resource assignment based on p2p alignment
  pci: refactor function pbus_size_mem
  ppc/pci: override pcibios_window_alignment
  ppc/pnv: I/O and memory alignment for p2p bridges

-----

arch/powerpc/include/asm/machdep.h        |    3 +
arch/powerpc/kernel/pci-common.c          |   20 ++++++++
arch/powerpc/platforms/powernv/pci-ioda.c |   38 +++++++++++++++
drivers/pci/host-bridge.c                 |   35 +++++++++-----
drivers/pci/setup-bus.c                   |   74 ++++++++++++++++++++++------
include/linux/pci.h                       |    7 ++-
6 files changed, 148 insertions(+), 29 deletions(-)

Thanks,
Gavin

[PATCH 4/8] pci: weak function returns alignment

[Gavin Shan]

The patch implements the weak function to return the default I/O
or memory alignment for P2P bridge. Currently, I/O window has 4KiB
alignment and memory window is 4MiB aligned by default. On the other
hand, those platforms (e.g. powernv) that have special requirements
on the alignment could override the function by themselves.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
---
 drivers/pci/setup-bus.c |   24 ++++++++++++++++++++++++
 include/linux/pci.h     |    2 ++
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index fb50613..826a4f3 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -697,6 +697,30 @@ 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 */
+
+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)
+		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 a47a4d3..739be31 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1034,6 +1034,8 @@ 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)
-- 
1.7.5.4