PCI: iproc: Use the EROM outbound window on BCMA

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 767012397976 ("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: 767012397976 ("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

0 files changed, 0 insertions, 0 deletions