[v13,12/16] PCI: Check pref compatible bit for mem64 resource of PCIe device

diff --git a/arch/sparc/kernel/pci_common.c b/arch/sparc/kernel/pci_common.c
index 1ebc7ff..6f206a1 100644
--- a/arch/sparc/kernel/pci_common.c
+++ b/arch/sparc/kernel/pci_common.c
@@ -343,7 +343,7 @@  static void pci_register_region(struct pci_bus *bus, const char *name,
 	region.start = rstart;
 	region.end = rstart + size - 1UL;
 	pcibios_bus_to_resource(bus, res, &region);
-	bus_res = pci_find_bus_resource(bus, res);
+	bus_res = pci_find_bus_resource(bus, res, res->flags);
 	if (!bus_res) {
 		kfree(res);
 		return;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 81c6cf9..f4ad1e0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -415,7 +415,7 @@  int pci_find_ht_capability(struct pci_dev *dev, int ht_cap)
 EXPORT_SYMBOL_GPL(pci_find_ht_capability);
 
 struct resource *pci_find_bus_resource(const struct pci_bus *bus,
-					struct resource *res)
+					struct resource *res, int flags)
 {
 	struct resource *r;
 	int i;
@@ -430,7 +430,7 @@  struct resource *pci_find_bus_resource(const struct pci_bus *bus,
 			 * not, the allocator made a mistake.
 			 */
 			if (r->flags & IORESOURCE_PREFETCH &&
-			    !(res->flags & IORESOURCE_PREFETCH))
+			    !(flags & IORESOURCE_PREFETCH))
 				return NULL;
 
 			/*
@@ -458,7 +458,9 @@  struct resource *pci_find_bus_resource(const struct pci_bus *bus,
 struct resource *pci_find_parent_resource(const struct pci_dev *dev,
 					  struct resource *res)
 {
-	return pci_find_bus_resource(dev->bus, res);
+	int flags = pci_resource_pref_compatible(dev, res);
+
+	return pci_find_bus_resource(dev->bus, res, flags);
 }
 EXPORT_SYMBOL(pci_find_parent_resource);
 
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 7d339c3..4508a1f 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -336,4 +336,6 @@  static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 }
 #endif
 
+int pci_resource_pref_compatible(const struct pci_dev *dev,
+				 struct resource *res);
 #endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 8e3ef72..5d11dec 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1732,6 +1732,36 @@  static void pci_dma_configure(struct pci_dev *dev)
 	pci_put_host_bridge_device(bridge);
 }
 
+static bool pci_up_path_over_pcie(struct pci_bus *bus)
+{
+	if (pci_is_root_bus(bus))
+		return true;
+
+	if (bus->self && !pci_is_pcie(bus->self))
+		return false;
+
+	return pci_up_path_over_pcie(bus->parent);
+}
+
+/*
+ * According to
+ * https://www.pcisig.com/specifications/pciexpress/base2/PCIe_Base_r2.1_Errata_08Jun10.pdf
+ * page 13, system firmware could put some 64bit non-pref under 64bit pref,
+ * on some cases.
+ * Let's mark if entire path from the host to the adapter is over PCI
+ * Express. later will use that compute pref compaitable bit.
+ */
+static void pci_set_on_all_pcie_path(struct pci_dev *dev)
+{
+	if (!pci_is_pcie(dev))
+		return;
+
+	if (!pci_up_path_over_pcie(dev->bus))
+		return;
+
+	dev->on_all_pcie_path = 1;
+}
+
 void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 {
 	int ret;
@@ -1762,6 +1792,9 @@  void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	/* Initialize various capabilities */
 	pci_init_capabilities(dev);
 
+	/* After pcie_cap is assigned */
+	pci_set_on_all_pcie_path(dev);
+
 	/*
 	 * Add the device to our list of discovered devices
 	 * and the bus list for fixup functions, etc.
diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 55641a3..b3b1565 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -738,6 +738,20 @@  int pci_claim_bridge_resource(struct pci_dev *bridge, int i)
 	return -EINVAL;
 }
 
+int pci_resource_pref_compatible(const struct pci_dev *dev,
+				 struct resource *res)
+{
+	if (res->flags & IORESOURCE_PREFETCH)
+		return res->flags;
+
+	if ((res->flags & IORESOURCE_MEM) &&
+	    (res->flags & IORESOURCE_MEM_64) &&
+	    dev->on_all_pcie_path)
+		return res->flags | IORESOURCE_PREFETCH;
+
+	return res->flags;
+}
+
 /* Check whether the bridge supports optional I/O and
    prefetchable memory ranges. If not, the respective
    base/limit registers must be read-only and read as 0. */
@@ -1035,11 +1049,12 @@  static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
 		for (i = 0; i < PCI_NUM_RESOURCES; i++) {
 			struct resource *r = &dev->resource[i];
 			resource_size_t r_size;
+			int flags = pci_resource_pref_compatible(dev, r);
 
-			if (r->parent || (r->flags & IORESOURCE_PCI_FIXED) ||
-			    ((r->flags & mask) != type &&
-			     (r->flags & mask) != type2 &&
-			     (r->flags & mask) != type3))
+			if (r->parent || (flags & IORESOURCE_PCI_FIXED) ||
+			    ((flags & mask) != type &&
+			     (flags & mask) != type2 &&
+			     (flags & mask) != type3))
 				continue;
 			r_size = resource_size(r);
 #ifdef CONFIG_PCI_IOV
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 66c4d8f..f741fed 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -257,15 +257,19 @@  static int __pci_assign_resource(struct pci_bus *bus, struct pci_dev *dev,
 static int _pci_assign_resource(struct pci_dev *dev, int resno,
 				resource_size_t size, resource_size_t min_align)
 {
+	struct resource *res = dev->resource + resno;
+	int old_flags = res->flags;
 	struct pci_bus *bus;
 	int ret;
 
+	res->flags = pci_resource_pref_compatible(dev, res);
 	bus = dev->bus;
 	while ((ret = __pci_assign_resource(bus, dev, resno, size, min_align))) {
 		if (!bus->parent || !bus->self->transparent)
 			break;
 		bus = bus->parent;
 	}
+	res->flags = old_flags;
 
 	return ret;
 }
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8214b24..3f158c4 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -303,6 +303,7 @@  struct pci_dev {
 						   powered on/off by the
 						   corresponding bridge */
 	unsigned int	ignore_hotplug:1;	/* Ignore hotplug events */
+	unsigned int	on_all_pcie_path:1;	/* up to host-bridge all pcie */
 	unsigned int	d3_delay;	/* D3->D0 transition time in ms */
 	unsigned int	d3cold_delay;	/* D3cold->D0 transition time in ms */
 
@@ -806,7 +807,7 @@  void pcibios_resource_to_bus(struct pci_bus *bus, struct pci_bus_region *region,
 void pcibios_bus_to_resource(struct pci_bus *bus, struct resource *res,
 			     struct pci_bus_region *region);
 struct resource *pci_find_bus_resource(const struct pci_bus *bus,
-					struct resource *res);
+					struct resource *res, int flags);
 void pcibios_scan_specific_bus(int busn);
 struct pci_bus *pci_find_bus(int domain, int busnr);
 void pci_bus_add_devices(const struct pci_bus *bus);