[PATCH] PCI: iproc: Use pci_alloc_host_bridge() on BCMA

[Semih Baskan]

The BCMA driver takes its register base and, since commit 552aa843e4c5
("PCI: iproc: Use the EROM outbound window on BCMA"), its outbound
window from what bcma read out of the enumeration ROM. It still
allocates its host bridge with devm_pci_alloc_host_bridge(), which since
commit 669cbc708122 ("PCI: Move DT resource setup into
devm_pci_alloc_host_bridge()") parses ranges, dma-ranges and bus-range
from the device's OF node and requests the windows it finds. None of
that reaches the hardware here: need_ob_cfg is only ever set by the
platform driver, so iproc_pcie_setup() never maps the parsed windows,
and the EROM commit above had to throw them away again to keep them
from colliding with its own window.

Allocate the bridge with pci_alloc_host_bridge() instead, so nothing
from the devicetree is requested or handed to the PCI core, and free it
on the error paths and in remove(). The driver now sets
bridge->dev.parent itself, as devm_pci_alloc_host_bridge() did, since
the wifi nodes under pcie_bridge0 in bcm4709-netgear-r8000.dts are
resolved through the root bus. The window request
moves from devm to request_resource() and release_resource() because
the resource lives inside the bridge allocation and has to be released
before the bridge is freed.

The ranges property is still read, but only to compare. bcm-ns.dtsi
describes the same window for the platform driver, and on core revision
0x01 it points at an address the hardware does not decode. The warning
from the EROM commit stays for that reason: a wrong dts is visible on
BCMA boots, where nothing else would show it. Without bus-range the
root bus also logs "No busn resource found for root bus, will use
[bus 00-ff]" again, which changes nothing else.

With PCIE_IPROC_PLATFORM and PCIE_IPROC_BCMA both enabled, the platform
driver binds the same nodes first and claims the devicetree window. On
core revision 0x07 that is the EROM window, so this driver's request
still fails and the probe backs out as before. On revision 0x01 the
devicetree window is elsewhere, so this driver now probes as well, next
to a platform driver instance whose window the hardware does not decode.
That instance does not work either; the only difference is that the
second probe is no longer stopped by the collision.

Tested on an ASUS RT-N18U (BCM47081, core revision 0x01): the warning
lines are identical to the applied version, /proc/iomem and the
enumerated devices are unchanged.

Suggested-by: Bjorn Helgaas <helgaas@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20260911191429.GA549927@bhelgaas/
Signed-off-by: Semih Baskan <strst.gs@xxxxxxxxx>
---
 drivers/pci/controller/pcie-iproc-bcma.c | 70 +++++++++++++++++-------
 1 file changed, 49 insertions(+), 21 deletions(-)

diff --git a/drivers/pci/controller/pcie-iproc-bcma.c b/drivers/pci/controller/pcie-iproc-bcma.c
index 06a471f4a..fcae83ed5 100644
--- a/drivers/pci/controller/pcie-iproc-bcma.c
+++ b/drivers/pci/controller/pcie-iproc-bcma.c
@@ -11,6 +11,7 @@
 #include <linux/phy/phy.h>
 #include <linux/bcma/bcma.h>
 #include <linux/ioport.h>
+#include <linux/of_address.h>
 
 #include "pcie-iproc.h"
 
@@ -31,18 +32,42 @@ static int iproc_bcma_pcie_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 	return bcma_core_irq(bdev, 5);
 }
 
+static void iproc_bcma_pcie_check_dt_window(struct iproc_pcie *pcie)
+{
+	struct device_node *np = pcie->dev->of_node;
+	struct of_pci_range_parser parser;
+	struct of_pci_range range;
+	struct resource res;
+
+	if (!np || of_pci_range_parser_init(&parser, np))
+		return;
+
+	for_each_of_pci_range(&parser, &range) {
+		if ((range.flags & IORESOURCE_TYPE_BITS) != IORESOURCE_MEM)
+			continue;
+
+		if (of_pci_range_to_resource(&range, np, &res))
+			continue;
+
+		if (res.start != pcie->mem.start || res.end != pcie->mem.end)
+			dev_warn(pcie->dev, "DT window %pR does not match EROM window %pR, using EROM\n",
+				 &res, &pcie->mem);
+	}
+}
+
 static int iproc_bcma_pcie_probe(struct bcma_device *bdev)
 {
 	struct device *dev = &bdev->dev;
 	struct iproc_pcie *pcie;
 	struct pci_host_bridge *bridge;
-	struct resource_entry *win, *tmp;
 	int ret;
 
-	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
+	bridge = pci_alloc_host_bridge(sizeof(*pcie));
 	if (!bridge)
 		return -ENOMEM;
 
+	bridge->dev.parent = dev;
+
 	pcie = pci_host_bridge_priv(bridge);
 
 	pcie->dev = dev;
@@ -51,7 +76,8 @@ static int iproc_bcma_pcie_probe(struct bcma_device *bdev)
 	pcie->base = bdev->io_addr;
 	if (!pcie->base) {
 		dev_err(dev, "no controller registers\n");
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto err_free_bridge;
 	}
 
 	pcie->base_addr = bdev->addr;
@@ -60,37 +86,39 @@ static int iproc_bcma_pcie_probe(struct bcma_device *bdev)
 	pcie->mem.end = bdev->addr_s[0] + SZ_128M - 1;
 	pcie->mem.name = "PCIe MEM space";
 	pcie->mem.flags = IORESOURCE_MEM;
-
-	resource_list_for_each_entry_safe(win, tmp, &bridge->windows) {
-		if (resource_type(win->res) != IORESOURCE_MEM)
-			continue;
-
-		if (win->res->start != pcie->mem.start ||
-		    win->res->end != pcie->mem.end)
-			dev_warn(dev, "DT window %pR does not match EROM window %pR, using EROM\n",
-				 win->res, &pcie->mem);
-
-		devm_release_resource(dev, win->res);
-		resource_list_destroy_entry(win);
-	}
-
+	iproc_bcma_pcie_check_dt_window(pcie);
 	pci_add_resource(&bridge->windows, &pcie->mem);
-	ret = devm_request_resource(dev, &iomem_resource, &pcie->mem);
-	if (ret)
-		return ret;
+	ret = request_resource(&iomem_resource, &pcie->mem);
+	if (ret) {
+		dev_err(dev, "can't claim %pR\n", &pcie->mem);
+		goto err_free_bridge;
+	}
 
 	bridge->map_irq = iproc_bcma_pcie_map_irq;
 
 	bcma_set_drvdata(bdev, pcie);
 
-	return iproc_pcie_setup(pcie, &bridge->windows);
+	ret = iproc_pcie_setup(pcie, &bridge->windows);
+	if (ret)
+		goto err_release_mem;
+
+	return 0;
+
+err_release_mem:
+	release_resource(&pcie->mem);
+err_free_bridge:
+	pci_free_host_bridge(bridge);
+	return ret;
 }
 
 static void iproc_bcma_pcie_remove(struct bcma_device *bdev)
 {
 	struct iproc_pcie *pcie = bcma_get_drvdata(bdev);
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
 
 	iproc_pcie_remove(pcie);
+	release_resource(&pcie->mem);
+	pci_free_host_bridge(bridge);
 }
 
 static const struct bcma_device_id iproc_bcma_pcie_table[] = {
-- 
2.43.0