[SRU Impish][PATCH 2/2] PCI: xgene: Revert "PCI: xgene: Use inbound resources for setup"

[dann frazier]

From: Marc Zyngier <maz at kernel.org>

BugLink: https://bugs.launchpad.net/bugs/1952933

Commit 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup")
killed PCIe on my XGene-1 box (a Mustang board). The machine itself
is still alive, but half of its storage (over NVMe) is gone, and the
NVMe driver just times out.

Note that this machine boots with a device tree provided by the
UEFI firmware (2016 vintage), which could well be non conformant
with the spec, hence the breakage.

With the patch reverted, the box boots 5.17-rc8 with flying colors.

Link: https://lore.kernel.org/all/Yf2wTLjmcRj+AbDv@xps13.dannf
Link: https://lore.kernel.org/r/20220321104843.949645-2-maz@kernel.org
Fixes: 6dce5aa59e0b ("PCI: xgene: Use inbound resources for setup")
Signed-off-by: Marc Zyngier <maz at kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: stable at vger.kernel.org
Cc: Rob Herring <robh at kernel.org>
Cc: Toan Le <toan at os.amperecomputing.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Krzysztof Wilczyński <kw at linux.com>
Cc: Bjorn Helgaas <bhelgaas at google.com>
Cc: Stéphane Graber <stgraber at ubuntu.com>
Cc: dann frazier <dann.frazier at canonical.com>
(backported from commit 1874b6d7ab1bdc900e8398026350313ac29caddb)
[dannf: minor context adjustment]
Signed-off-by: dann frazier <dann.frazier at canonical.com>
---
 drivers/pci/controller/pci-xgene.c | 33 ++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/controller/pci-xgene.c b/drivers/pci/controller/pci-xgene.c
index 7f503dd4ff81..33c90c0d9bfb 100644
--- a/drivers/pci/controller/pci-xgene.c
+++ b/drivers/pci/controller/pci-xgene.c
@@ -480,28 +480,27 @@ static int xgene_pcie_select_ib_reg(u8 *ib_reg_mask, u64 size)
 }
 
 static void xgene_pcie_setup_ib_reg(struct xgene_pcie_port *port,
-				    struct resource_entry *entry,
-				    u8 *ib_reg_mask)
+				    struct of_pci_range *range, u8 *ib_reg_mask)
 {
 	void __iomem *cfg_base = port->cfg_base;
 	struct device *dev = port->dev;
 	void *bar_addr;
 	u32 pim_reg;
-	u64 cpu_addr = entry->res->start;
-	u64 pci_addr = cpu_addr - entry->offset;
-	u64 size = resource_size(entry->res);
+	u64 cpu_addr = range->cpu_addr;
+	u64 pci_addr = range->pci_addr;
+	u64 size = range->size;
 	u64 mask = ~(size - 1) | EN_REG;
 	u32 flags = PCI_BASE_ADDRESS_MEM_TYPE_64;
 	u32 bar_low;
 	int region;
 
-	region = xgene_pcie_select_ib_reg(ib_reg_mask, size);
+	region = xgene_pcie_select_ib_reg(ib_reg_mask, range->size);
 	if (region < 0) {
 		dev_warn(dev, "invalid pcie dma-range config\n");
 		return;
 	}
 
-	if (entry->res->flags & IORESOURCE_PREFETCH)
+	if (range->flags & IORESOURCE_PREFETCH)
 		flags |= PCI_BASE_ADDRESS_MEM_PREFETCH;
 
 	bar_low = pcie_bar_low_val((u32)cpu_addr, flags);
@@ -532,13 +531,25 @@ static void xgene_pcie_setup_ib_reg(struct xgene_pcie_port *port,
 
 static int xgene_pcie_parse_map_dma_ranges(struct xgene_pcie_port *port)
 {
-	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(port);
-	struct resource_entry *entry;
+	struct device_node *np = port->node;
+	struct of_pci_range range;
+	struct of_pci_range_parser parser;
+	struct device *dev = port->dev;
 	u8 ib_reg_mask = 0;
 
-	resource_list_for_each_entry(entry, &bridge->dma_ranges)
-		xgene_pcie_setup_ib_reg(port, entry, &ib_reg_mask);
+	if (of_pci_dma_range_parser_init(&parser, np)) {
+		dev_err(dev, "missing dma-ranges property\n");
+		return -EINVAL;
+	}
+
+	/* Get the dma-ranges from DT */
+	for_each_of_pci_range(&parser, &range) {
+		u64 end = range.cpu_addr + range.size - 1;
 
+		dev_dbg(dev, "0x%08x 0x%016llx..0x%016llx -> 0x%016llx\n",
+			range.flags, range.cpu_addr, end, range.pci_addr);
+		xgene_pcie_setup_ib_reg(port, &range, &ib_reg_mask);
+	}
 	return 0;
 }
 
-- 
2.36.1