diff mbox

[v8,1/3] of/pci: Unify pci_process_bridge_OF_ranges from Microblaze and PowerPC

Message ID 1366627295-16964-2-git-send-email-Andrew.Murray@arm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Andrew Murray April 22, 2013, 10:41 a.m. UTC
The pci_process_bridge_OF_ranges function, used to parse the "ranges"
property of a PCI host device, is found in both Microblaze and PowerPC
architectures. These implementations are nearly identical. This patch
moves this common code to a common place.

Signed-off-by: Andrew Murray <Andrew.Murray@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Reviewed-by: Rob Herring <rob.herring@calxeda.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Michal Simek <monstr@monstr.eu>
Acked-by: Grant Likely <grant.likely@linaro.org>
---
 arch/microblaze/include/asm/pci-bridge.h |    5 +-
 arch/microblaze/pci/pci-common.c         |  192 ----------------------------
 arch/powerpc/include/asm/pci-bridge.h    |    5 +-
 arch/powerpc/kernel/pci-common.c         |  192 ----------------------------
 drivers/of/of_pci.c                      |  200 ++++++++++++++++++++++++++++++
 include/linux/of_pci.h                   |    4 +
 6 files changed, 206 insertions(+), 392 deletions(-)

Comments

Benjamin Herrenschmidt May 5, 2013, 2:41 a.m. UTC | #1
On Mon, 2013-04-22 at 11:41 +0100, Andrew Murray wrote:
> The pci_process_bridge_OF_ranges function, used to parse the "ranges"
> property of a PCI host device, is found in both Microblaze and PowerPC
> architectures. These implementations are nearly identical. This patch
> moves this common code to a common place.

What's happening with this ? I'd like to avoid that patch for now
as I'm doing some changes to pci_process_bridge_OF_ranges
which are fairly urgent (I might even stick them in the current
merge window) to deal with memory windows having separate offsets.

There's also a few hacks in there that are really ppc specific...

I think the right long term approach is to change the way powerpc
(and microblaze ?) initializes PCI host bridges. Move it away from
setup_arch() (which is a PITA anyway since it's way too early) to
an early init call of some sort, and encapsulate the new struct
pci_host_bridge.

We can then directly configure the host bridge windows rather
than having this "intermediary" set of resources in our pci_controller
and in fact move most of the fields from pci_controller to
pci_host_bridge to the point where the former can remain as a
simple platform specific wrapper if needed.

So for new stuff (hint: DT based ARM PCI) or stuff that has to deal with
a lot less archaic platforms (hint: Microblaze), I'd recommend going
straight for that approach rather than perpetuating the PowerPC code
which I'll try to deal with in the next few monthes.

Cheers,
Ben.
Andrew Murray May 7, 2013, 8:01 a.m. UTC | #2
On Sun, May 05, 2013 at 03:41:49AM +0100, Benjamin Herrenschmidt wrote:
> On Mon, 2013-04-22 at 11:41 +0100, Andrew Murray wrote:
> > The pci_process_bridge_OF_ranges function, used to parse the "ranges"
> > property of a PCI host device, is found in both Microblaze and PowerPC
> > architectures. These implementations are nearly identical. This patch
> > moves this common code to a common place.
> 
> What's happening with this ? I'd like to avoid that patch for now
> as I'm doing some changes to pci_process_bridge_OF_ranges
> which are fairly urgent (I might even stick them in the current
> merge window) to deal with memory windows having separate offsets.

There were no objections to this latest revision until now and it is
currently sitting with Jason Cooper (mvebu-next/pcie). [1]

> 
> There's also a few hacks in there that are really ppc specific...
> 
> I think the right long term approach is to change the way powerpc
> (and microblaze ?) initializes PCI host bridges. Move it away from
> setup_arch() (which is a PITA anyway since it's way too early) to
> an early init call of some sort, and encapsulate the new struct
> pci_host_bridge.
> 
> We can then directly configure the host bridge windows rather
> than having this "intermediary" set of resources in our pci_controller
> and in fact move most of the fields from pci_controller to
> pci_host_bridge to the point where the former can remain as a
> simple platform specific wrapper if needed.

This is a view that was also shared by Bjorn [2] when I attempted to
submit a patchset which moves struct pci_controller to asm-generic.

> 
> So for new stuff (hint: DT based ARM PCI) or stuff that has to deal with
> a lot less archaic platforms (hint: Microblaze), I'd recommend going
> straight for that approach rather than perpetuating the PowerPC code
> which I'll try to deal with in the next few monthes.

The motativation for my patchsets were to give a way for ARM PCI host
bridge drivers to parse the DT ranges property, but this snow-balled into
unifying pci_process_bridge_OF_ranges.

My v8 patchset provides a of_pci_range_parser which is used directly by a
few ARM PCI DT host bridge drivers, this has been generally accepted and
tested. I don't see why this can't remain and so I'd really like to keep this
around. 

Grant, Benjamin would you be happy for me to resubmit this series which provides
the of_pci_range_parser which will be used by the separate implementations of
pci_process_bridge_OF_ranges in PowerPC/Microblaze?

Benjamin are you able to still use of_pci_range_parser in your
'Support per-aperture memory offset' patch?

Thanks,

Andrew Murray

[1] https://lkml.org/lkml/2013/4/22/505
[2] https://patchwork.kernel.org/patch/2487671

> 
> Cheers,
> Ben.
>  
> 
>
Benjamin Herrenschmidt May 7, 2013, 10:19 a.m. UTC | #3
On Tue, 2013-05-07 at 09:01 +0100, Andrew Murray wrote:
> 
> There were no objections to this latest revision until now and it is
> currently sitting with Jason Cooper (mvebu-next/pcie). [1]

Ok, well I've just sent Linus a pull request for my changes so at least
drop the powerpc changes from your tree for the time being.

> This is a view that was also shared by Bjorn [2] when I attempted to
> submit a patchset which moves struct pci_controller to asm-generic.

Right, it's the logical way to go

> The motativation for my patchsets were to give a way for ARM PCI host
> bridge drivers to parse the DT ranges property, but this snow-balled
> into unifying pci_process_bridge_OF_ranges.

Which I understand, I would probably have done the same thing in your
shoes :-)

> My v8 patchset provides a of_pci_range_parser which is used directly
> by a few ARM PCI DT host bridge drivers, this has been generally
> accepted and tested. I don't see why this can't remain and so I'd
> really like to keep this around. 

Sure, no objection, in fact I should/could probably update my new code
to use it as well.

> Grant, Benjamin would you be happy for me to resubmit this series
> which provides the of_pci_range_parser which will be used by the
> separate implementations of pci_process_bridge_OF_ranges in
> PowerPC/Microblaze?

Sure, in fact feel free to update my new code if you have more bandwidth
than I do, it should hit Linus tree soon hopefully unless he objects to
me having a second pull request this merge window...

> Benjamin are you able to still use of_pci_range_parser in your
> 'Support per-aperture memory offset' patch?

I see no reason why not. I just haven't looked into it much, I admit,
being bogged down with a pile of new HW bringup in the lab etc...

Cheers,
Ben.
diff mbox

Patch

diff --git a/arch/microblaze/include/asm/pci-bridge.h b/arch/microblaze/include/asm/pci-bridge.h
index cb5d397..5783cd6 100644
--- a/arch/microblaze/include/asm/pci-bridge.h
+++ b/arch/microblaze/include/asm/pci-bridge.h
@@ -10,6 +10,7 @@ 
 #include <linux/pci.h>
 #include <linux/list.h>
 #include <linux/ioport.h>
+#include <linux/of_pci.h>
 
 struct device_node;
 
@@ -132,10 +133,6 @@  extern void setup_indirect_pci(struct pci_controller *hose,
 extern struct pci_controller *pci_find_hose_for_OF_device(
 			struct device_node *node);
 
-/* Fill up host controller resources from the OF node */
-extern void pci_process_bridge_OF_ranges(struct pci_controller *hose,
-			struct device_node *dev, int primary);
-
 /* Allocate & free a PCI host bridge structure */
 extern struct pci_controller *pcibios_alloc_controller(struct device_node *dev);
 extern void pcibios_free_controller(struct pci_controller *phb);
diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index 9ea521e..2735ad9 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -622,198 +622,6 @@  void pci_resource_to_user(const struct pci_dev *dev, int bar,
 	*end = rsrc->end - offset;
 }
 
-/**
- * pci_process_bridge_OF_ranges - Parse PCI bridge resources from device tree
- * @hose: newly allocated pci_controller to be setup
- * @dev: device node of the host bridge
- * @primary: set if primary bus (32 bits only, soon to be deprecated)
- *
- * This function will parse the "ranges" property of a PCI host bridge device
- * node and setup the resource mapping of a pci controller based on its
- * content.
- *
- * Life would be boring if it wasn't for a few issues that we have to deal
- * with here:
- *
- *   - We can only cope with one IO space range and up to 3 Memory space
- *     ranges. However, some machines (thanks Apple !) tend to split their
- *     space into lots of small contiguous ranges. So we have to coalesce.
- *
- *   - We can only cope with all memory ranges having the same offset
- *     between CPU addresses and PCI addresses. Unfortunately, some bridges
- *     are setup for a large 1:1 mapping along with a small "window" which
- *     maps PCI address 0 to some arbitrary high address of the CPU space in
- *     order to give access to the ISA memory hole.
- *     The way out of here that I've chosen for now is to always set the
- *     offset based on the first resource found, then override it if we
- *     have a different offset and the previous was set by an ISA hole.
- *
- *   - Some busses have IO space not starting at 0, which causes trouble with
- *     the way we do our IO resource renumbering. The code somewhat deals with
- *     it for 64 bits but I would expect problems on 32 bits.
- *
- *   - Some 32 bits platforms such as 4xx can have physical space larger than
- *     32 bits so we need to use 64 bits values for the parsing
- */
-void pci_process_bridge_OF_ranges(struct pci_controller *hose,
-				  struct device_node *dev, int primary)
-{
-	const u32 *ranges;
-	int rlen;
-	int pna = of_n_addr_cells(dev);
-	int np = pna + 5;
-	int memno = 0, isa_hole = -1;
-	u32 pci_space;
-	unsigned long long pci_addr, cpu_addr, pci_next, cpu_next, size;
-	unsigned long long isa_mb = 0;
-	struct resource *res;
-
-	pr_info("PCI host bridge %s %s ranges:\n",
-	       dev->full_name, primary ? "(primary)" : "");
-
-	/* Get ranges property */
-	ranges = of_get_property(dev, "ranges", &rlen);
-	if (ranges == NULL)
-		return;
-
-	/* Parse it */
-	pr_debug("Parsing ranges property...\n");
-	while ((rlen -= np * 4) >= 0) {
-		/* Read next ranges element */
-		pci_space = ranges[0];
-		pci_addr = of_read_number(ranges + 1, 2);
-		cpu_addr = of_translate_address(dev, ranges + 3);
-		size = of_read_number(ranges + pna + 3, 2);
-
-		pr_debug("pci_space: 0x%08x pci_addr:0x%016llx ",
-				pci_space, pci_addr);
-		pr_debug("cpu_addr:0x%016llx size:0x%016llx\n",
-					cpu_addr, size);
-
-		ranges += np;
-
-		/* If we failed translation or got a zero-sized region
-		 * (some FW try to feed us with non sensical zero sized regions
-		 * such as power3 which look like some kind of attempt
-		 * at exposing the VGA memory hole)
-		 */
-		if (cpu_addr == OF_BAD_ADDR || size == 0)
-			continue;
-
-		/* Now consume following elements while they are contiguous */
-		for (; rlen >= np * sizeof(u32);
-		     ranges += np, rlen -= np * 4) {
-			if (ranges[0] != pci_space)
-				break;
-			pci_next = of_read_number(ranges + 1, 2);
-			cpu_next = of_translate_address(dev, ranges + 3);
-			if (pci_next != pci_addr + size ||
-			    cpu_next != cpu_addr + size)
-				break;
-			size += of_read_number(ranges + pna + 3, 2);
-		}
-
-		/* Act based on address space type */
-		res = NULL;
-		switch ((pci_space >> 24) & 0x3) {
-		case 1:		/* PCI IO space */
-			pr_info("  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr);
-
-			/* We support only one IO range */
-			if (hose->pci_io_size) {
-				pr_info(" \\--> Skipped (too many) !\n");
-				continue;
-			}
-			/* On 32 bits, limit I/O space to 16MB */
-			if (size > 0x01000000)
-				size = 0x01000000;
-
-			/* 32 bits needs to map IOs here */
-			hose->io_base_virt = ioremap(cpu_addr, size);
-
-			/* Expect trouble if pci_addr is not 0 */
-			if (primary)
-				isa_io_base =
-					(unsigned long)hose->io_base_virt;
-			/* pci_io_size and io_base_phys always represent IO
-			 * space starting at 0 so we factor in pci_addr
-			 */
-			hose->pci_io_size = pci_addr + size;
-			hose->io_base_phys = cpu_addr - pci_addr;
-
-			/* Build resource */
-			res = &hose->io_resource;
-			res->flags = IORESOURCE_IO;
-			res->start = pci_addr;
-			break;
-		case 2:		/* PCI Memory space */
-		case 3:		/* PCI 64 bits Memory space */
-			pr_info(" MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr,
-			       (pci_space & 0x40000000) ? "Prefetch" : "");
-
-			/* We support only 3 memory ranges */
-			if (memno >= 3) {
-				pr_info(" \\--> Skipped (too many) !\n");
-				continue;
-			}
-			/* Handles ISA memory hole space here */
-			if (pci_addr == 0) {
-				isa_mb = cpu_addr;
-				isa_hole = memno;
-				if (primary || isa_mem_base == 0)
-					isa_mem_base = cpu_addr;
-				hose->isa_mem_phys = cpu_addr;
-				hose->isa_mem_size = size;
-			}
-
-			/* We get the PCI/Mem offset from the first range or
-			 * the, current one if the offset came from an ISA
-			 * hole. If they don't match, bugger.
-			 */
-			if (memno == 0 ||
-			    (isa_hole >= 0 && pci_addr != 0 &&
-			     hose->pci_mem_offset == isa_mb))
-				hose->pci_mem_offset = cpu_addr - pci_addr;
-			else if (pci_addr != 0 &&
-				 hose->pci_mem_offset != cpu_addr - pci_addr) {
-				pr_info(" \\--> Skipped (offset mismatch) !\n");
-				continue;
-			}
-
-			/* Build resource */
-			res = &hose->mem_resources[memno++];
-			res->flags = IORESOURCE_MEM;
-			if (pci_space & 0x40000000)
-				res->flags |= IORESOURCE_PREFETCH;
-			res->start = cpu_addr;
-			break;
-		}
-		if (res != NULL) {
-			res->name = dev->full_name;
-			res->end = res->start + size - 1;
-			res->parent = NULL;
-			res->sibling = NULL;
-			res->child = NULL;
-		}
-	}
-
-	/* If there's an ISA hole and the pci_mem_offset is -not- matching
-	 * the ISA hole offset, then we need to remove the ISA hole from
-	 * the resource list for that brige
-	 */
-	if (isa_hole >= 0 && hose->pci_mem_offset != isa_mb) {
-		unsigned int next = isa_hole + 1;
-		pr_info(" Removing ISA hole at 0x%016llx\n", isa_mb);
-		if (next < memno)
-			memmove(&hose->mem_resources[isa_hole],
-				&hose->mem_resources[next],
-				sizeof(struct resource) * (memno - next));
-		hose->mem_resources[--memno].flags = 0;
-	}
-}
-
 /* Decide whether to display the domain number in /proc */
 int pci_proc_domain(struct pci_bus *bus)
 {
diff --git a/arch/powerpc/include/asm/pci-bridge.h b/arch/powerpc/include/asm/pci-bridge.h
index 025a130..205bfba 100644
--- a/arch/powerpc/include/asm/pci-bridge.h
+++ b/arch/powerpc/include/asm/pci-bridge.h
@@ -10,6 +10,7 @@ 
 #include <linux/pci.h>
 #include <linux/list.h>
 #include <linux/ioport.h>
+#include <linux/of_pci.h>
 #include <asm-generic/pci-bridge.h>
 
 struct device_node;
@@ -231,10 +232,6 @@  extern int pcibios_map_io_space(struct pci_bus *bus);
 extern struct pci_controller *pci_find_hose_for_OF_device(
 			struct device_node* node);
 
-/* Fill up host controller resources from the OF node */
-extern void pci_process_bridge_OF_ranges(struct pci_controller *hose,
-			struct device_node *dev, int primary);
-
 /* Allocate & free a PCI host bridge structure */
 extern struct pci_controller *pcibios_alloc_controller(struct device_node *dev);
 extern void pcibios_free_controller(struct pci_controller *phb);
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index fa12ae4..6edf396 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -640,198 +640,6 @@  void pci_resource_to_user(const struct pci_dev *dev, int bar,
 	*end = rsrc->end - offset;
 }
 
-/**
- * pci_process_bridge_OF_ranges - Parse PCI bridge resources from device tree
- * @hose: newly allocated pci_controller to be setup
- * @dev: device node of the host bridge
- * @primary: set if primary bus (32 bits only, soon to be deprecated)
- *
- * This function will parse the "ranges" property of a PCI host bridge device
- * node and setup the resource mapping of a pci controller based on its
- * content.
- *
- * Life would be boring if it wasn't for a few issues that we have to deal
- * with here:
- *
- *   - We can only cope with one IO space range and up to 3 Memory space
- *     ranges. However, some machines (thanks Apple !) tend to split their
- *     space into lots of small contiguous ranges. So we have to coalesce.
- *
- *   - We can only cope with all memory ranges having the same offset
- *     between CPU addresses and PCI addresses. Unfortunately, some bridges
- *     are setup for a large 1:1 mapping along with a small "window" which
- *     maps PCI address 0 to some arbitrary high address of the CPU space in
- *     order to give access to the ISA memory hole.
- *     The way out of here that I've chosen for now is to always set the
- *     offset based on the first resource found, then override it if we
- *     have a different offset and the previous was set by an ISA hole.
- *
- *   - Some busses have IO space not starting at 0, which causes trouble with
- *     the way we do our IO resource renumbering. The code somewhat deals with
- *     it for 64 bits but I would expect problems on 32 bits.
- *
- *   - Some 32 bits platforms such as 4xx can have physical space larger than
- *     32 bits so we need to use 64 bits values for the parsing
- */
-void pci_process_bridge_OF_ranges(struct pci_controller *hose,
-				  struct device_node *dev, int primary)
-{
-	const u32 *ranges;
-	int rlen;
-	int pna = of_n_addr_cells(dev);
-	int np = pna + 5;
-	int memno = 0, isa_hole = -1;
-	u32 pci_space;
-	unsigned long long pci_addr, cpu_addr, pci_next, cpu_next, size;
-	unsigned long long isa_mb = 0;
-	struct resource *res;
-
-	printk(KERN_INFO "PCI host bridge %s %s ranges:\n",
-	       dev->full_name, primary ? "(primary)" : "");
-
-	/* Get ranges property */
-	ranges = of_get_property(dev, "ranges", &rlen);
-	if (ranges == NULL)
-		return;
-
-	/* Parse it */
-	while ((rlen -= np * 4) >= 0) {
-		/* Read next ranges element */
-		pci_space = ranges[0];
-		pci_addr = of_read_number(ranges + 1, 2);
-		cpu_addr = of_translate_address(dev, ranges + 3);
-		size = of_read_number(ranges + pna + 3, 2);
-		ranges += np;
-
-		/* If we failed translation or got a zero-sized region
-		 * (some FW try to feed us with non sensical zero sized regions
-		 * such as power3 which look like some kind of attempt at exposing
-		 * the VGA memory hole)
-		 */
-		if (cpu_addr == OF_BAD_ADDR || size == 0)
-			continue;
-
-		/* Now consume following elements while they are contiguous */
-		for (; rlen >= np * sizeof(u32);
-		     ranges += np, rlen -= np * 4) {
-			if (ranges[0] != pci_space)
-				break;
-			pci_next = of_read_number(ranges + 1, 2);
-			cpu_next = of_translate_address(dev, ranges + 3);
-			if (pci_next != pci_addr + size ||
-			    cpu_next != cpu_addr + size)
-				break;
-			size += of_read_number(ranges + pna + 3, 2);
-		}
-
-		/* Act based on address space type */
-		res = NULL;
-		switch ((pci_space >> 24) & 0x3) {
-		case 1:		/* PCI IO space */
-			printk(KERN_INFO
-			       "  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr);
-
-			/* We support only one IO range */
-			if (hose->pci_io_size) {
-				printk(KERN_INFO
-				       " \\--> Skipped (too many) !\n");
-				continue;
-			}
-#ifdef CONFIG_PPC32
-			/* On 32 bits, limit I/O space to 16MB */
-			if (size > 0x01000000)
-				size = 0x01000000;
-
-			/* 32 bits needs to map IOs here */
-			hose->io_base_virt = ioremap(cpu_addr, size);
-
-			/* Expect trouble if pci_addr is not 0 */
-			if (primary)
-				isa_io_base =
-					(unsigned long)hose->io_base_virt;
-#endif /* CONFIG_PPC32 */
-			/* pci_io_size and io_base_phys always represent IO
-			 * space starting at 0 so we factor in pci_addr
-			 */
-			hose->pci_io_size = pci_addr + size;
-			hose->io_base_phys = cpu_addr - pci_addr;
-
-			/* Build resource */
-			res = &hose->io_resource;
-			res->flags = IORESOURCE_IO;
-			res->start = pci_addr;
-			break;
-		case 2:		/* PCI Memory space */
-		case 3:		/* PCI 64 bits Memory space */
-			printk(KERN_INFO
-			       " MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr,
-			       (pci_space & 0x40000000) ? "Prefetch" : "");
-
-			/* We support only 3 memory ranges */
-			if (memno >= 3) {
-				printk(KERN_INFO
-				       " \\--> Skipped (too many) !\n");
-				continue;
-			}
-			/* Handles ISA memory hole space here */
-			if (pci_addr == 0) {
-				isa_mb = cpu_addr;
-				isa_hole = memno;
-				if (primary || isa_mem_base == 0)
-					isa_mem_base = cpu_addr;
-				hose->isa_mem_phys = cpu_addr;
-				hose->isa_mem_size = size;
-			}
-
-			/* We get the PCI/Mem offset from the first range or
-			 * the, current one if the offset came from an ISA
-			 * hole. If they don't match, bugger.
-			 */
-			if (memno == 0 ||
-			    (isa_hole >= 0 && pci_addr != 0 &&
-			     hose->pci_mem_offset == isa_mb))
-				hose->pci_mem_offset = cpu_addr - pci_addr;
-			else if (pci_addr != 0 &&
-				 hose->pci_mem_offset != cpu_addr - pci_addr) {
-				printk(KERN_INFO
-				       " \\--> Skipped (offset mismatch) !\n");
-				continue;
-			}
-
-			/* Build resource */
-			res = &hose->mem_resources[memno++];
-			res->flags = IORESOURCE_MEM;
-			if (pci_space & 0x40000000)
-				res->flags |= IORESOURCE_PREFETCH;
-			res->start = cpu_addr;
-			break;
-		}
-		if (res != NULL) {
-			res->name = dev->full_name;
-			res->end = res->start + size - 1;
-			res->parent = NULL;
-			res->sibling = NULL;
-			res->child = NULL;
-		}
-	}
-
-	/* If there's an ISA hole and the pci_mem_offset is -not- matching
-	 * the ISA hole offset, then we need to remove the ISA hole from
-	 * the resource list for that brige
-	 */
-	if (isa_hole >= 0 && hose->pci_mem_offset != isa_mb) {
-		unsigned int next = isa_hole + 1;
-		printk(KERN_INFO " Removing ISA hole at 0x%016llx\n", isa_mb);
-		if (next < memno)
-			memmove(&hose->mem_resources[isa_hole],
-				&hose->mem_resources[next],
-				sizeof(struct resource) * (memno - next));
-		hose->mem_resources[--memno].flags = 0;
-	}
-}
-
 /* Decide whether to display the domain number in /proc */
 int pci_proc_domain(struct pci_bus *bus)
 {
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 13e37e2..1626172 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -4,6 +4,10 @@ 
 #include <linux/of_pci.h>
 #include <asm/prom.h>
 
+#if defined(CONFIG_PPC32) || defined(CONFIG_PPC64) || defined(CONFIG_MICROBLAZE)
+#include <asm/pci-bridge.h>
+#endif
+
 static inline int __of_pci_pci_compare(struct device_node *node,
 				       unsigned int devfn)
 {
@@ -40,3 +44,199 @@  struct device_node *of_pci_find_child_device(struct device_node *parent,
 	return NULL;
 }
 EXPORT_SYMBOL_GPL(of_pci_find_child_device);
+
+/**
+ * pci_process_bridge_OF_ranges - Parse PCI bridge resources from device tree
+ * @hose: newly allocated pci_controller to be setup
+ * @dev: device node of the host bridge
+ * @primary: set if primary bus (32 bits only, soon to be deprecated)
+ *
+ * This function will parse the "ranges" property of a PCI host bridge device
+ * node and setup the resource mapping of a pci controller based on its
+ * content.
+ *
+ * Life would be boring if it wasn't for a few issues that we have to deal
+ * with here:
+ *
+ *   - We can only cope with one IO space range and up to 3 Memory space
+ *     ranges. However, some machines (thanks Apple !) tend to split their
+ *     space into lots of small contiguous ranges. So we have to coalesce.
+ *
+ *   - We can only cope with all memory ranges having the same offset
+ *     between CPU addresses and PCI addresses. Unfortunately, some bridges
+ *     are setup for a large 1:1 mapping along with a small "window" which
+ *     maps PCI address 0 to some arbitrary high address of the CPU space in
+ *     order to give access to the ISA memory hole.
+ *     The way out of here that I've chosen for now is to always set the
+ *     offset based on the first resource found, then override it if we
+ *     have a different offset and the previous was set by an ISA hole.
+ *
+ *   - Some busses have IO space not starting at 0, which causes trouble with
+ *     the way we do our IO resource renumbering. The code somewhat deals with
+ *     it for 64 bits but I would expect problems on 32 bits.
+ *
+ *   - Some 32 bits platforms such as 4xx can have physical space larger than
+ *     32 bits so we need to use 64 bits values for the parsing
+ */
+#if defined(CONFIG_PPC32) || defined(CONFIG_PPC64) || defined(CONFIG_MICROBLAZE)
+void pci_process_bridge_OF_ranges(struct pci_controller *hose,
+				  struct device_node *dev, int primary)
+{
+	const u32 *ranges;
+	int rlen;
+	int pna = of_n_addr_cells(dev);
+	int np = pna + 5;
+	int memno = 0, isa_hole = -1;
+	u32 pci_space;
+	unsigned long long pci_addr, cpu_addr, pci_next, cpu_next, size;
+	unsigned long long isa_mb = 0;
+	struct resource *res;
+
+	pr_info("PCI host bridge %s %s ranges:\n",
+	       dev->full_name, primary ? "(primary)" : "");
+
+	/* Get ranges property */
+	ranges = of_get_property(dev, "ranges", &rlen);
+	if (ranges == NULL)
+		return;
+
+	/* Parse it */
+	pr_debug("Parsing ranges property...\n");
+	while ((rlen -= np * 4) >= 0) {
+		/* Read next ranges element */
+		pci_space = ranges[0];
+		pci_addr = of_read_number(ranges + 1, 2);
+		cpu_addr = of_translate_address(dev, ranges + 3);
+		size = of_read_number(ranges + pna + 3, 2);
+
+		pr_debug("pci_space: 0x%08x pci_addr:0x%016llx ",
+				pci_space, pci_addr);
+		pr_debug("cpu_addr:0x%016llx size:0x%016llx\n",
+					cpu_addr, size);
+
+		ranges += np;
+
+		/* If we failed translation or got a zero-sized region
+		 * (some FW try to feed us with non sensical zero sized regions
+		 * such as power3 which look like some kind of attempt
+		 * at exposing the VGA memory hole)
+		 */
+		if (cpu_addr == OF_BAD_ADDR || size == 0)
+			continue;
+
+		/* Now consume following elements while they are contiguous */
+		for (; rlen >= np * sizeof(u32);
+		     ranges += np, rlen -= np * 4) {
+			if (ranges[0] != pci_space)
+				break;
+			pci_next = of_read_number(ranges + 1, 2);
+			cpu_next = of_translate_address(dev, ranges + 3);
+			if (pci_next != pci_addr + size ||
+			    cpu_next != cpu_addr + size)
+				break;
+			size += of_read_number(ranges + pna + 3, 2);
+		}
+
+		/* Act based on address space type */
+		res = NULL;
+		switch ((pci_space >> 24) & 0x3) {
+		case 1:		/* PCI IO space */
+			pr_info("  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
+			       cpu_addr, cpu_addr + size - 1, pci_addr);
+
+			/* We support only one IO range */
+			if (hose->pci_io_size) {
+				pr_info(" \\--> Skipped (too many) !\n");
+				continue;
+			}
+#if (!IS_ENABLED(CONFIG_64BIT))
+			/* On 32 bits, limit I/O space to 16MB */
+			if (size > 0x01000000)
+				size = 0x01000000;
+
+			/* 32 bits needs to map IOs here */
+			hose->io_base_virt = ioremap(cpu_addr, size);
+
+			/* Expect trouble if pci_addr is not 0 */
+			if (primary)
+				isa_io_base =
+					(unsigned long)hose->io_base_virt;
+#endif /* !CONFIG_64BIT */
+			/* pci_io_size and io_base_phys always represent IO
+			 * space starting at 0 so we factor in pci_addr
+			 */
+			hose->pci_io_size = pci_addr + size;
+			hose->io_base_phys = cpu_addr - pci_addr;
+
+			/* Build resource */
+			res = &hose->io_resource;
+			res->flags = IORESOURCE_IO;
+			res->start = pci_addr;
+			break;
+		case 2:		/* PCI Memory space */
+		case 3:		/* PCI 64 bits Memory space */
+			pr_info(" MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
+			       cpu_addr, cpu_addr + size - 1, pci_addr,
+			       (pci_space & 0x40000000) ? "Prefetch" : "");
+
+			/* We support only 3 memory ranges */
+			if (memno >= 3) {
+				pr_info(" \\--> Skipped (too many) !\n");
+				continue;
+			}
+			/* Handles ISA memory hole space here */
+			if (pci_addr == 0) {
+				isa_mb = cpu_addr;
+				isa_hole = memno;
+				if (primary || isa_mem_base == 0)
+					isa_mem_base = cpu_addr;
+				hose->isa_mem_phys = cpu_addr;
+				hose->isa_mem_size = size;
+			}
+
+			/* We get the PCI/Mem offset from the first range or
+			 * the, current one if the offset came from an ISA
+			 * hole. If they don't match, bugger.
+			 */
+			if (memno == 0 ||
+			    (isa_hole >= 0 && pci_addr != 0 &&
+			     hose->pci_mem_offset == isa_mb))
+				hose->pci_mem_offset = cpu_addr - pci_addr;
+			else if (pci_addr != 0 &&
+				 hose->pci_mem_offset != cpu_addr - pci_addr) {
+				pr_info(" \\--> Skipped (offset mismatch) !\n");
+				continue;
+			}
+
+			/* Build resource */
+			res = &hose->mem_resources[memno++];
+			res->flags = IORESOURCE_MEM;
+			if (pci_space & 0x40000000)
+				res->flags |= IORESOURCE_PREFETCH;
+			res->start = cpu_addr;
+			break;
+		}
+		if (res != NULL) {
+			res->name = dev->full_name;
+			res->end = res->start + size - 1;
+			res->parent = NULL;
+			res->sibling = NULL;
+			res->child = NULL;
+		}
+	}
+
+	/* If there's an ISA hole and the pci_mem_offset is -not- matching
+	 * the ISA hole offset, then we need to remove the ISA hole from
+	 * the resource list for that brige
+	 */
+	if (isa_hole >= 0 && hose->pci_mem_offset != isa_mb) {
+		unsigned int next = isa_hole + 1;
+		pr_info(" Removing ISA hole at 0x%016llx\n", isa_mb);
+		if (next < memno)
+			memmove(&hose->mem_resources[isa_hole],
+				&hose->mem_resources[next],
+				sizeof(struct resource) * (memno - next));
+		hose->mem_resources[--memno].flags = 0;
+	}
+}
+#endif
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index bb115de..33e8ead 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -11,4 +11,8 @@  struct device_node;
 struct device_node *of_pci_find_child_device(struct device_node *parent,
 					     unsigned int devfn);
 
+struct pci_controller;
+void pci_process_bridge_OF_ranges(struct pci_controller *hose,
+			struct device_node *dev, int primary);
+
 #endif