Patchwork [v3] of/pci: Provide support for parsing PCI DT ranges property

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Submitter Andrew Murray
Date March 26, 2013, 4:20 p.m.
Message ID <20130326162022.GA25625@arm.com>
Download mbox | patch
Permalink /patch/231446/
State Not Applicable
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Comments

Andrew Murray - March 26, 2013, 4:20 p.m.
This patch factors out common implementation patterns to reduce overall kernel
code and provide a means for host bridge drivers to directly obtain struct
resources from the DT's ranges property without relying on architecture specific
DT handling. This will make it easier to write archiecture independent host bridge
drivers and mitigate against further duplication of DT parsing code.

This patch can be used in the following way:

	struct of_pci_range_parser parser;
	struct of_pci_range range;

	if (of_pci_range_parser(&parser, np))
		; //no ranges property

	for_each_of_pci_range(&parser, &range) {

		/*
			directly access properties of the address range, e.g.:
			range.pci_space, range.pci_addr, range.cpu_addr,
			range.size, range.flags

			alternatively obtain a struct resource, e.g.:
			struct resource res;
			of_pci_range_to_resource(&range, np, &res);
		*/
	}

Additionally the implementation takes care of adjacent ranges and merges them
into a single range (as was the case with powerpc and microblaze).

The modifications to microblaze, mips and powerpc have not been tested.

Signed-off-by: Andrew Murray <Andrew.Murray@arm.com>
Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
Compared to "[PATCH v5 01/17] of/pci: Provide support for parsing PCI DT
ranges property", the following changes have been made:

 * Correct use of IORESOURCE_* as suggested by Russell King

 * Improved interface and naming as suggested by Thierry Reding

Compared to the v2 sent by Andrew Murray, Thomas Petazzoni did:

 * Add a memset() on the struct of_pci_range_iter when starting the
   for loop in for_each_pci_range(). Otherwise, with an uninitialized
   of_pci_range_iter, of_pci_process_ranges() may crash.

 * Add parenthesis around 'res', 'np' and 'iter' in the
   for_each_of_pci_range macro definitions. Otherwise, passing
   something like &foobar as 'res' didn't work.

 * Rebased on top of 3.9-rc2, which required fixing a few conflicts in
   the Microblaze code.

v2:
  This follows on from suggestions made by Grant Likely
  (marc.info/?l=linux-kernel&m=136079602806328)
---
 arch/microblaze/pci/pci-common.c |  110 +++++++++++++------------------------
 arch/mips/pci/pci.c              |   50 ++++++------------
 arch/powerpc/kernel/pci-common.c |   99 ++++++++++++----------------------
 drivers/of/address.c             |   63 ++++++++++++++++++++++
 include/linux/of_address.h       |   42 ++++++++++++++
 5 files changed, 194 insertions(+), 170 deletions(-)
Thierry Reding - March 27, 2013, 1:04 p.m.
On Tue, Mar 26, 2013 at 04:20:23PM +0000, Andrew Murray wrote:
> This patch factors out common implementation patterns to reduce overall kernel
> code and provide a means for host bridge drivers to directly obtain struct
> resources from the DT's ranges property without relying on architecture specific
> DT handling. This will make it easier to write archiecture independent host bridge
> drivers and mitigate against further duplication of DT parsing code.
> 
> This patch can be used in the following way:
> 
> 	struct of_pci_range_parser parser;
> 	struct of_pci_range range;
> 
> 	if (of_pci_range_parser(&parser, np))
> 		; //no ranges property
> 
> 	for_each_of_pci_range(&parser, &range) {
> 
> 		/*
> 			directly access properties of the address range, e.g.:
> 			range.pci_space, range.pci_addr, range.cpu_addr,
> 			range.size, range.flags
> 
> 			alternatively obtain a struct resource, e.g.:
> 			struct resource res;
> 			of_pci_range_to_resource(&range, np, &res);
> 		*/
> 	}
> 
> Additionally the implementation takes care of adjacent ranges and merges them
> into a single range (as was the case with powerpc and microblaze).
> 
> The modifications to microblaze, mips and powerpc have not been tested.
> 
> Signed-off-by: Andrew Murray <Andrew.Murray@arm.com>
> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Jingoo Han - April 4, 2013, 12:57 a.m.
On Wednesday, March 27, 2013 10:04 PM, Thierry Reding wrote:
> 
> On Tue, Mar 26, 2013 at 04:20:23PM +0000, Andrew Murray wrote:
> > This patch factors out common implementation patterns to reduce overall kernel
> > code and provide a means for host bridge drivers to directly obtain struct
> > resources from the DT's ranges property without relying on architecture specific
> > DT handling. This will make it easier to write archiecture independent host bridge
> > drivers and mitigate against further duplication of DT parsing code.
> >
> > This patch can be used in the following way:
> >
> > 	struct of_pci_range_parser parser;
> > 	struct of_pci_range range;
> >
> > 	if (of_pci_range_parser(&parser, np))
> > 		; //no ranges property
> >
> > 	for_each_of_pci_range(&parser, &range) {
> >
> > 		/*
> > 			directly access properties of the address range, e.g.:
> > 			range.pci_space, range.pci_addr, range.cpu_addr,
> > 			range.size, range.flags
> >
> > 			alternatively obtain a struct resource, e.g.:
> > 			struct resource res;
> > 			of_pci_range_to_resource(&range, np, &res);
> > 		*/
> > 	}
> >
> > Additionally the implementation takes care of adjacent ranges and merges them
> > into a single range (as was the case with powerpc and microblaze).
> >
> > The modifications to microblaze, mips and powerpc have not been tested.
> >
> > Signed-off-by: Andrew Murray <Andrew.Murray@arm.com>
> > Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>
> > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> 
> Tested-by: Thierry Reding <thierry.reding@avionic-design.de>

It works properly with Exynos5440.

Tested-by: Jingoo Han <jg1.han@samsung.com>



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Patch

diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c
index 9ea521e..17a7ad1 100644
--- a/arch/microblaze/pci/pci-common.c
+++ b/arch/microblaze/pci/pci-common.c
@@ -658,67 +658,43 @@  void pci_resource_to_user(const struct pci_dev *dev, int bar,
 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;
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	u32 res_type;
 
 	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)
+	/* Check for ranges property */
+	if (of_pci_range_parser(&parser, dev))
 		return;
 
-	/* Parse it */
 	pr_debug("Parsing ranges property...\n");
-	while ((rlen -= np * 4) >= 0) {
+	for_each_of_pci_range(&parser, &range) {
 		/* 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;
+		pr_debug("pci_space: 0x%08x pci_addr: 0x%016llx ",
+				range.pci_space, range.pci_addr);
+		pr_debug("cpu_addr: 0x%016llx size: 0x%016llx\n",
+				range.cpu_addr, range.size);
 
 		/* 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)
+		if (range.cpu_addr == OF_BAD_ADDR || range.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 */
+		res_type = range.flags & IORESOURCE_TYPE_BITS;
+		if (res_type == IORESOURCE_IO) {
 			pr_info("  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr);
+				range.cpu_addr, range.cpu_addr + range.size - 1,
+				range.pci_addr);
 
 			/* We support only one IO range */
 			if (hose->pci_io_size) {
@@ -726,11 +702,12 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 				continue;
 			}
 			/* On 32 bits, limit I/O space to 16MB */
-			if (size > 0x01000000)
-				size = 0x01000000;
+			if (range.size > 0x01000000)
+				range.size = 0x01000000;
 
 			/* 32 bits needs to map IOs here */
-			hose->io_base_virt = ioremap(cpu_addr, size);
+			hose->io_base_virt = ioremap(range.cpu_addr,
+						range.size);
 
 			/* Expect trouble if pci_addr is not 0 */
 			if (primary)
@@ -739,19 +716,18 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			/* 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;
+			hose->pci_io_size = range.pci_addr + range.size;
+			hose->io_base_phys = range.cpu_addr - range.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 */
+			range.cpu_addr = range.pci_addr;
+		} else if (res_type == IORESOURCE_MEM) {
 			pr_info(" MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr,
-			       (pci_space & 0x40000000) ? "Prefetch" : "");
+				range.cpu_addr, range.cpu_addr + range.size - 1,
+				range.pci_addr,
+				(range.pci_space & 0x40000000) ?
+				"Prefetch" : "");
 
 			/* We support only 3 memory ranges */
 			if (memno >= 3) {
@@ -759,13 +735,13 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 				continue;
 			}
 			/* Handles ISA memory hole space here */
-			if (pci_addr == 0) {
+			if (range.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;
+					isa_mem_base = range.cpu_addr;
+				hose->isa_mem_phys = range.cpu_addr;
+				hose->isa_mem_size = range.size;
 			}
 
 			/* We get the PCI/Mem offset from the first range or
@@ -773,30 +749,22 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			 * hole. If they don't match, bugger.
 			 */
 			if (memno == 0 ||
-			    (isa_hole >= 0 && pci_addr != 0 &&
+			    (isa_hole >= 0 && range.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) {
+				hose->pci_mem_offset = range.cpu_addr
+							- range.pci_addr;
+			else if (range.pci_addr != 0 &&
+				 hose->pci_mem_offset != range.cpu_addr
+							- range.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 (res != NULL)
+			of_pci_range_to_resource(&range, dev, res);
 	}
 
 	/* If there's an ISA hole and the pci_mem_offset is -not- matching
diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c
index 0872f12..bee49a4 100644
--- a/arch/mips/pci/pci.c
+++ b/arch/mips/pci/pci.c
@@ -122,51 +122,33 @@  static void pcibios_scanbus(struct pci_controller *hose)
 #ifdef CONFIG_OF
 void pci_load_of_ranges(struct pci_controller *hose, struct device_node *node)
 {
-	const __be32 *ranges;
-	int rlen;
-	int pna = of_n_addr_cells(node);
-	int np = pna + 5;
+	struct of_pci_range_range range;
+	struct of_pci_range_parser parser;
+	u32 res_type;
 
 	pr_info("PCI host bridge %s ranges:\n", node->full_name);
-	ranges = of_get_property(node, "ranges", &rlen);
-	if (ranges == NULL)
-		return;
 	hose->of_node = node;
 
-	while ((rlen -= np * 4) >= 0) {
-		u32 pci_space;
+	if (of_pci_range_parser(&parser, node))
+		return;
+
+	for_each_of_pci_range(&parser, &range) {
 		struct resource *res = NULL;
-		u64 addr, size;
-
-		pci_space = be32_to_cpup(&ranges[0]);
-		addr = of_translate_address(node, ranges + 3);
-		size = of_read_number(ranges + pna + 3, 2);
-		ranges += np;
-		switch ((pci_space >> 24) & 0x3) {
-		case 1:		/* PCI IO space */
+
+		res_type = range.flags & IORESOURCE_TYPE_BITS;
+		if (res_type == IORESOURCE_IO) {
 			pr_info("  IO 0x%016llx..0x%016llx\n",
-					addr, addr + size - 1);
+				range.addr, range.addr + range.size - 1);
 			hose->io_map_base =
-				(unsigned long)ioremap(addr, size);
+				(unsigned long)ioremap(range.addr, range.size);
 			res = hose->io_resource;
-			res->flags = IORESOURCE_IO;
-			break;
-		case 2:		/* PCI Memory space */
-		case 3:		/* PCI 64 bits Memory space */
+		} else if (res_type == IORESOURCE_MEM) {
 			pr_info(" MEM 0x%016llx..0x%016llx\n",
-					addr, addr + size - 1);
+				range.addr, range.addr + range.size - 1);
 			res = hose->mem_resource;
-			res->flags = IORESOURCE_MEM;
-			break;
-		}
-		if (res != NULL) {
-			res->start = addr;
-			res->name = node->full_name;
-			res->end = res->start + size - 1;
-			res->parent = NULL;
-			res->sibling = NULL;
-			res->child = NULL;
 		}
+		if (res != NULL)
+			of_pci_range_to_resource(&range, node, res);
 	}
 }
 #endif
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index fa12ae4..878d530 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -676,61 +676,37 @@  void pci_resource_to_user(const struct pci_dev *dev, int bar,
 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;
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	u32 res_type;
 
 	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)
+	/* Check for ranges property */
+	if (of_pci_range_parser(&parser, dev))
 		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;
-
+	for_each_of_pci_range(&parser, &range) {
 		/* 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)
+		if (range.cpu_addr == OF_BAD_ADDR || range.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 */
+		res_type = range.flags & IORESOURCE_TYPE_BITS;
+		if (res_type == IORESOURCE_IO) {
 			printk(KERN_INFO
 			       "  IO 0x%016llx..0x%016llx -> 0x%016llx\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr);
+				range.cpu_addr, range.cpu_addr + range.size - 1,
+				range.pci_addr);
 
 			/* We support only one IO range */
 			if (hose->pci_io_size) {
@@ -740,11 +716,12 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			}
 #ifdef CONFIG_PPC32
 			/* On 32 bits, limit I/O space to 16MB */
-			if (size > 0x01000000)
-				size = 0x01000000;
+			if (range.size > 0x01000000)
+				range.size = 0x01000000;
 
 			/* 32 bits needs to map IOs here */
-			hose->io_base_virt = ioremap(cpu_addr, size);
+			hose->io_base_virt = ioremap(range.cpu_addr,
+						range.size);
 
 			/* Expect trouble if pci_addr is not 0 */
 			if (primary)
@@ -754,20 +731,19 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			/* 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;
+			hose->pci_io_size = range.pci_addr + range.size;
+			hose->io_base_phys = range.cpu_addr - range.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 */
+			range.cpu_addr = range.pci_addr;
+		} else if (res_type == IORESOURCE_MEM) {
 			printk(KERN_INFO
 			       " MEM 0x%016llx..0x%016llx -> 0x%016llx %s\n",
-			       cpu_addr, cpu_addr + size - 1, pci_addr,
-			       (pci_space & 0x40000000) ? "Prefetch" : "");
+				range.cpu_addr, range.cpu_addr + range.size - 1,
+				range.pci_addr,
+				(range.pci_space & 0x40000000) ?
+				"Prefetch" : "");
 
 			/* We support only 3 memory ranges */
 			if (memno >= 3) {
@@ -776,13 +752,13 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 				continue;
 			}
 			/* Handles ISA memory hole space here */
-			if (pci_addr == 0) {
+			if (range.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;
+					isa_mem_base = range.cpu_addr;
+				hose->isa_mem_phys = range.cpu_addr;
+				hose->isa_mem_size = range.size;
 			}
 
 			/* We get the PCI/Mem offset from the first range or
@@ -790,11 +766,13 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 			 * hole. If they don't match, bugger.
 			 */
 			if (memno == 0 ||
-			    (isa_hole >= 0 && pci_addr != 0 &&
+			(isa_hole >= 0 && range.pci_addr != 0 &&
 			     hose->pci_mem_offset == isa_mb))
-				hose->pci_mem_offset = cpu_addr - pci_addr;
+				hose->pci_mem_offset = range.cpu_addr -
+							range.pci_addr;
 			else if (pci_addr != 0 &&
-				 hose->pci_mem_offset != cpu_addr - pci_addr) {
+				hose->pci_mem_offset != range.cpu_addr -
+							range.pci_addr) {
 				printk(KERN_INFO
 				       " \\--> Skipped (offset mismatch) !\n");
 				continue;
@@ -802,19 +780,10 @@  void pci_process_bridge_OF_ranges(struct pci_controller *hose,
 
 			/* 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 (res != NULL)
+			of_pci_range_to_resource(&range, dev, res);
 	}
 
 	/* If there's an ISA hole and the pci_mem_offset is -not- matching
diff --git a/drivers/of/address.c b/drivers/of/address.c
index 04da786..e87f45e 100644
--- a/drivers/of/address.c
+++ b/drivers/of/address.c
@@ -227,6 +227,69 @@  int of_pci_address_to_resource(struct device_node *dev, int bar,
 	return __of_address_to_resource(dev, addrp, size, flags, NULL, r);
 }
 EXPORT_SYMBOL_GPL(of_pci_address_to_resource);
+
+int of_pci_range_parser(struct of_pci_range_parser *parser,
+			struct device_node *node)
+{
+	const int na = 3, ns = 2;
+	int rlen;
+
+	parser->node = node;
+	parser->pna = of_n_addr_cells(node);
+	parser->np = parser->pna + na + ns;
+
+	parser->range = of_get_property(node, "ranges", &rlen);
+	if (parser->range == NULL)
+		return -ENOENT;
+
+	parser->end = parser->range + rlen / sizeof(__be32);
+
+	return 0;
+}
+
+struct of_pci_range *of_pci_process_ranges(struct of_pci_range_parser *parser,
+						struct of_pci_range *range)
+{
+	const int na = 3, ns = 2;
+
+	if (!parser->range || parser->range + parser->np > parser->end)
+		return NULL;
+
+	range->pci_space = be32_to_cpup(parser->range);
+	range->flags = of_bus_pci_get_flags(parser->range);
+	range->pci_addr = of_read_number(parser->range + 1, ns);
+	range->cpu_addr = of_translate_address(parser->node,
+				parser->range + na);
+	range->size = of_read_number(parser->range + parser->pna + na, ns);
+
+	parser->range += parser->np;
+
+	/* Now consume following elements while they are contiguous */
+	while (parser->range + parser->np <= parser->end) {
+		u32 flags, pci_space;
+		u64 pci_addr, cpu_addr, size;
+
+		pci_space = be32_to_cpup(parser->range);
+		flags = of_bus_pci_get_flags(parser->range);
+		pci_addr = of_read_number(parser->range + 1, ns);
+		cpu_addr = of_translate_address(parser->node,
+				parser->range + na);
+		size = of_read_number(parser->range + parser->pna + na, ns);
+
+		if (flags != range->flags)
+			break;
+		if (pci_addr != range->pci_addr + range->size ||
+		    cpu_addr != range->cpu_addr + range->size)
+			break;
+
+		range->size += size;
+		parser->range += parser->np;
+	}
+
+	return range;
+}
+EXPORT_SYMBOL_GPL(of_pci_process_ranges);
+
 #endif /* CONFIG_PCI */
 
 /*
diff --git a/include/linux/of_address.h b/include/linux/of_address.h
index 0506eb5..c7003a3 100644
--- a/include/linux/of_address.h
+++ b/include/linux/of_address.h
@@ -4,6 +4,32 @@ 
 #include <linux/errno.h>
 #include <linux/of.h>
 
+struct of_pci_range_parser {
+	struct device_node *node;
+	const __be32 *range, *end;
+	int np, pna;
+};
+
+struct of_pci_range {
+	u32 pci_space;
+	u64 pci_addr;
+	u64 cpu_addr;
+	u64 size;
+	u32 flags;
+};
+
+#define for_each_of_pci_range(parser, range) \
+	for (; of_pci_process_ranges(parser, range);)
+
+#define of_pci_range_to_resource(range, np, res) \
+	do { \
+		(res)->flags = (range)->flags; \
+		(res)->start = (range)->cpu_addr; \
+		(res)->end = (range)->cpu_addr + (range)->size - 1; \
+		(res)->parent = (res)->child = (res)->sibling = NULL; \
+		(res)->name = (np)->full_name; \
+	} while (0)
+
 #ifdef CONFIG_OF_ADDRESS
 extern u64 of_translate_address(struct device_node *np, const __be32 *addr);
 extern bool of_can_translate_address(struct device_node *dev);
@@ -27,6 +53,10 @@  static inline unsigned long pci_address_to_pio(phys_addr_t addr) { return -1; }
 #define pci_address_to_pio pci_address_to_pio
 #endif
 
+int of_pci_range_parser(struct of_pci_range_parser *parser,
+			struct device_node *node);
+struct of_pci_range *of_pci_process_ranges(struct of_pci_range_parser *parser,
+						struct of_pci_range *range);
 #else /* CONFIG_OF_ADDRESS */
 #ifndef of_address_to_resource
 static inline int of_address_to_resource(struct device_node *dev, int index,
@@ -53,6 +83,18 @@  static inline const __be32 *of_get_address(struct device_node *dev, int index,
 {
 	return NULL;
 }
+
+int of_pci_range_parser(struct of_pci_range_parser *parser,
+			struct device_noed *node)
+{
+	return -1;
+}
+
+struct of_pci_range *of_pci_process_ranges(struct of_pci_range_parser *parser,
+						struct of_pci_range *range)
+{
+	return NULL;
+}
 #endif /* CONFIG_OF_ADDRESS */