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PCI: iproc: Use the EROM outbound window on BCMA

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The PCIe outbound window base on Northstar depends on the PCIe Gen2 core
revision. Revision 0x01 uses 0x08000000, 0x40000000 and 0x48000000 for
controllers 0 to 2, while revision 0x07 (NS-B0) uses 0x08000000,
0x20000000 and 0x28000000. Broadcom's own driver branches on the core
revision for exactly this reason.

bcm-ns.dtsi is shared by every Northstar SoC, so it cannot carry a value
that is correct on both. Commit 7670123979 ("ARM: dts: BCM5301X:
Describe PCIe controllers fully") gave the controllers a ranges property.
The commit shipped in v7.1.

With that property present, two things go wrong with this driver:

  1) devm_pci_alloc_host_bridge() parses those ranges and requests them,
     then this driver adds its own window and requests the whole list a
     second time, so every controller fails to probe with -EBUSY.

  2) The DT window itself is only correct on core revision 0x07. On
     revision 0x01 it points at an address the hardware does not decode,
     and the first MMIO access to a BAR takes an imprecise external abort.

The enumeration ROM reports the correct base for the revision actually
present, and bcma already provides it as addr_s[0].

To solve 1), use pci_alloc_host_bridge() directly to avoid the request of
all the DT resources done in pci_parse_request_of_pci_ranges(). Instead,
request the memory window from the EROM.

To solve 2), parse the memory resources from DT and emit a warning if it
describes a window that doesn't match the window from the EROM.  The
mismatch means the devicetree describes a window the hardware does not
decode, and that should be fixed in the dts rather than ignored silently.

The driver is correct whether or not the DT describes a window.

The same commit also added compatible = "brcm,iproc-pcie", so these
nodes now match pcie-iproc-platform. With CONFIG_PCIE_IPROC_PLATFORM
enabled, which is the default on ARCH_BCM_IPROC, that driver binds them
first and this driver's probe fails inside devm_pci_alloc_host_bridge().
This commit fixes the configurations where the BCMA driver is the one in
use; OpenWrt builds that way, with PCIE_IPROC_PLATFORM disabled. The
platform path takes the DT window as-is and has the same wrong address
on core revision 0x01, so that side needs a devicetree fix either way.

Based on:
  https://patch.msgid.link/20260807160526.379-1-strst.gs@gmail.com
  https://patch.msgid.link/20260912043626.437-1-strst.gs@gmail.com

Fixes: 7670123979 ("ARM: dts: BCM5301X: Describe PCIe controllers fully")
Signed-off-by: Semih Baskan <strst.gs@gmail.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Tested-by: Semih Baskan <strst.gs@gmail.com>
Link: https://patch.msgid.link/20261013220421.1588051-3-bhelgaas@google.com
This commit is contained in:
Semih Baskan 2026-10-13 17:04:21 -05:00 committed by Bjorn Helgaas
parent 39d1c645bb
commit 9850907ee1
1 changed files with 37 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
drivers/pci/controller/pcie-iproc-bcma.c
View File

@ -11,7 +11,9 @@
#include <linux/phy/phy.h>
#include <linux/bcma/bcma.h>
#include <linux/ioport.h>
#include <linux/of_address.h>
#include "../pci.h"
#include "pcie-iproc.h"
@ -31,6 +33,29 @@ 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;
@ -38,10 +63,20 @@ static int iproc_bcma_pcie_probe(struct bcma_device *bdev)
struct pci_host_bridge *bridge;
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;
ret = devm_add_action_or_reset(dev, devm_pci_alloc_host_bridge_release,
bridge);
if (ret)
return -ENOMEM;
bridge->swizzle_irq = pci_common_swizzle;
bridge->map_irq = iproc_bcma_pcie_map_irq;
pcie = pci_host_bridge_priv(bridge);
pcie->dev = dev;
@ -59,13 +94,12 @@ 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;
iproc_bcma_pcie_check_dt_window(pcie);
pci_add_resource(&bridge->windows, &pcie->mem);
ret = devm_request_pci_bus_resources(dev, &bridge->windows);
if (ret)
return ret;
bridge->map_irq = iproc_bcma_pcie_map_irq;
bcma_set_drvdata(bdev, pcie);
return iproc_pcie_setup(pcie, &bridge->windows);