[PATCH v2 1/4] ARM/PCI: remove align_resource callback in pcibios_align_resource

[Zhou Wang <wangzhou1-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org>]

This patch had added by Arnd Bergmann during last reviewing of v1 patchset[1].

PCI core codes call pcibios_align_resource(). In ARM specific one, it will
dereference pci_sys_data and call sys->align_resource. If we try to unify ARM
and ARM64 PCIe API in pcie-designware. it will bring kernel crash when run into
this dereferencing.

However, in ARM there is only pci-mvebu which implements align_resource. So
add align_resource call back in pci_host_bridge structure and override
pcibios_align_resource with it.

Signed-off-by: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>
Signed-off-by: Zhou Wang <wangzhou1-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org>
Tested-by: Fabrice Gasnier <fabrice.gasnier-qxv4g6HH51o@public.gmane.org>

[1] http://www.spinics.net/lists/linux-pci/msg41671.html
---
 arch/arm/kernel/bios32.c     |  4 ----
 drivers/pci/host/pci-mvebu.c | 47 ++++++++++++++++++++++++++++----------------
 drivers/pci/setup-res.c      | 27 ++++++++++++++++++++-----
 include/linux/pci.h          |  3 +++
 4 files changed, 55 insertions(+), 26 deletions(-)

diff --git a/arch/arm/kernel/bios32.c b/arch/arm/kernel/bios32.c
index fcbbbb1..47588dc 100644
--- a/arch/arm/kernel/bios32.c
+++ b/arch/arm/kernel/bios32.c
@@ -468,7 +468,6 @@ static void pcibios_init_hw(struct device *parent, struct hw_pci *hw,
 		sys->busnr   = busnr;
 		sys->swizzle = hw->swizzle;
 		sys->map_irq = hw->map_irq;
-		sys->align_resource = hw->align_resource;
 		INIT_LIST_HEAD(&sys->resources);
 
 		if (hw->private_data)
@@ -597,9 +596,6 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res,
 
 	start = (start + align - 1) & ~(align - 1);
 
-	if (sys->align_resource)
-		return sys->align_resource(dev, res, start, size, align);
-
 	return start;
 }
 
diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index 1ab8635..155d05f 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/drivers/pci/host/pci-mvebu.c
@@ -22,6 +22,8 @@
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 
+#include "../pci.h" /* HACK to see pci_find_host_bridge */
+
 /*
  * PCIe unit register offsets.
  */
@@ -751,27 +753,20 @@ static int mvebu_pcie_setup(int nr, struct pci_sys_data *sys)
 	return 1;
 }
 
-static struct pci_bus *mvebu_pcie_scan_bus(int nr, struct pci_sys_data *sys)
+static resource_size_t mvebu_pcie_align_resource(void *data,
+						 const struct resource *res,
+						 resource_size_t size,
+						 resource_size_t align)
 {
-	struct mvebu_pcie *pcie = sys_to_pcie(sys);
-	struct pci_bus *bus;
+	struct pci_dev *dev = data;
 
-	bus = pci_create_root_bus(&pcie->pdev->dev, sys->busnr,
-				  &mvebu_pcie_ops, sys, &sys->resources);
-	if (!bus)
-		return NULL;
+	resource_size_t start = res->start;
 
-	pci_scan_child_bus(bus);
+	if (res->flags & IORESOURCE_IO && start & 0x300)
+		start = (start + 0x3ff) & ~0x3ff;
 
-	return bus;
-}
+	start = (start + align - 1) & ~(align - 1);
 
-static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
-						 const struct resource *res,
-						 resource_size_t start,
-						 resource_size_t size,
-						 resource_size_t align)
-{
 	if (dev->bus->number != 0)
 		return start;
 
@@ -796,6 +791,25 @@ static resource_size_t mvebu_pcie_align_resource(struct pci_dev *dev,
 		return start;
 }
 
+static struct pci_bus *mvebu_pcie_scan_bus(int nr, struct pci_sys_data *sys)
+{
+	struct mvebu_pcie *pcie = sys_to_pcie(sys);
+	struct pci_host_bridge *phb;
+	struct pci_bus *bus;
+
+	bus = pci_create_root_bus(&pcie->pdev->dev, sys->busnr,
+				  &mvebu_pcie_ops, sys, &sys->resources);
+	if (!bus)
+		return NULL;
+
+	phb = pci_find_host_bridge(bus);
+	phb->align_resource = mvebu_pcie_align_resource;
+
+	pci_scan_child_bus(bus);
+
+	return bus;
+}
+
 static void mvebu_pcie_enable(struct mvebu_pcie *pcie)
 {
 	struct hw_pci hw;
@@ -812,7 +826,6 @@ static void mvebu_pcie_enable(struct mvebu_pcie *pcie)
 	hw.scan           = mvebu_pcie_scan_bus;
 	hw.map_irq        = of_irq_parse_and_map_pci;
 	hw.ops            = &mvebu_pcie_ops;
-	hw.align_resource = mvebu_pcie_align_resource;
 
 	pci_common_init(&hw);
 }
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 232f925..73abca7 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -200,7 +200,11 @@ static int pci_revert_fw_address(struct resource *res, struct pci_dev *dev,
 }
 
 static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
-		int resno, resource_size_t size, resource_size_t align)
+		int resno, resource_size_t size, resource_size_t align,
+		resource_size_t (*alignf)(void *,
+					  const struct resource *,
+					  resource_size_t,
+					  resource_size_t))
 {
 	struct resource *res = dev->resource + resno;
 	resource_size_t min;
@@ -217,7 +221,7 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 	 */
 	ret = pci_bus_alloc_resource(bus, res, size, align, min,
 				     IORESOURCE_PREFETCH | IORESOURCE_MEM_64,
-				     pcibios_align_resource, dev);
+				     alignf, dev);
 	if (ret == 0)
 		return 0;
 
@@ -229,7 +233,7 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 	     (IORESOURCE_PREFETCH | IORESOURCE_MEM_64)) {
 		ret = pci_bus_alloc_resource(bus, res, size, align, min,
 					     IORESOURCE_PREFETCH,
-					     pcibios_align_resource, dev);
+					     alignf, dev);
 		if (ret == 0)
 			return 0;
 	}
@@ -242,7 +246,7 @@ static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 	 */
 	if (res->flags & (IORESOURCE_PREFETCH | IORESOURCE_MEM_64))
 		ret = pci_bus_alloc_resource(bus, res, size, align, min, 0,
-					     pcibios_align_resource, dev);
+					     alignf, dev);
 
 	return ret;
 }
@@ -251,10 +255,23 @@ static int _pci_assign_resource(struct pci_dev *dev, int resno,
 				resource_size_t size, resource_size_t min_align)
 {
 	struct pci_bus *bus;
+	struct pci_host_bridge *phb;
+	resource_size_t (*alignf)(void *,
+				  const struct resource *,
+				  resource_size_t,
+				  resource_size_t);
 	int ret;
 
 	bus = dev->bus;
-	while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
+	phb = pci_find_host_bridge(bus);
+
+	if (phb->align_resource)
+		alignf = phb->align_resource;
+	else
+		alignf = pcibios_align_resource;
+
+	while ((ret = __pci_assign_resource(bus, dev, resno, size,
+					    min_align, alignf))) {
 		if (!bus->parent || !bus->self->transparent)
 			break;
 		bus = bus->parent;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 353db8d..39e48fc 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -404,6 +404,9 @@ struct pci_host_bridge {
 	struct device dev;
 	struct pci_bus *bus;		/* root bus */
 	struct list_head windows;	/* resource_entry */
+	resource_size_t (*align_resource)(void *data,
+			 const struct resource *res,
+			 resource_size_t size, resource_size_t align);
 	void (*release_fn)(struct pci_host_bridge *);
 	void *release_data;
 	unsigned int ignore_reset_delay:1;	/* for entire hierarchy */
-- 
1.9.1

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