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* [PATCH v3] PCI: loongson: Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk()
@ 2020-07-16  2:19 Tiezhu Yang
  2020-07-16  2:21 ` Huacai Chen
  2020-07-17 10:28 ` Lorenzo Pieralisi
  0 siblings, 2 replies; 4+ messages in thread
From: Tiezhu Yang @ 2020-07-16  2:19 UTC (permalink / raw)
  To: Lorenzo Pieralisi, Rob Herring, Bjorn Helgaas,
	Thomas Bogendoerfer, Huacai Chen, Jiaxun Yang
  Cc: linux-mips, linux-pci, linux-kernel, Xuefeng Li

According to the datasheet of Loongson LS7A bridge chip, the old version
of Loongson LS7A PCIE port has a hardware bug about PCI class. As far as
I know, the latest version has already fixed this bug.

In order to maintain downward compatibility, use DECLARE_PCI_FIXUP_EARLY
instead of DECLARE_PCI_FIXUP_HEADER for bridge_class_quirk() to fix it as
early as possible.

Otherwise, in the function pci_setup_device(), the related code about
"dev->class" such as "class = dev->class >> 8;" and "dev->transparent
= ((dev->class & 0xff) == 1);" maybe get wrong value due to without
EARLY fixup.

By the way, we can see that the PCI class fixup of other controllers are
all EARLY fixups:

[root@linux linux.git]# grep -rn -A 3 "PCI_CLASS_BRIDGE_PCI << 8" drivers/pci/controller/ | grep EARLY
drivers/pci/controller/pcie-tango.c-327-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0024, tango_fixup_class);
drivers/pci/controller/pcie-tango.c-328-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SIGMA, 0x0028, tango_fixup_class);
drivers/pci/controller/pci-tegra.c-775-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf0, tegra_pcie_fixup_class);
drivers/pci/controller/pci-tegra.c-776-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NVIDIA, 0x0bf1, tegra_pcie_fixup_class);
drivers/pci/controller/dwc/pcie-qcom.c-1442-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x0101, qcom_fixup_class);
drivers/pci/controller/dwc/pcie-qcom.c-1443-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x0104, qcom_fixup_class);
drivers/pci/controller/pcie-iproc-bcma.c-23-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0x8011, bcma_pcie2_fixup_class);
drivers/pci/controller/pcie-iproc-bcma.c-24-DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_BROADCOM, 0x8012, bcma_pcie2_fixup_class);

Fixes: 1f58cca5cf2b ("PCI: Add Loongson PCI Controller support")
Signed-off-by: Tiezhu Yang <>

v2: Modify the patch subject used with lower case "loongson"

v3: Update the commit message

 drivers/pci/controller/pci-loongson.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/controller/pci-loongson.c b/drivers/pci/controller/pci-loongson.c
index 459009c..58b862a 100644
--- a/drivers/pci/controller/pci-loongson.c
+++ b/drivers/pci/controller/pci-loongson.c
@@ -37,11 +37,11 @@ static void bridge_class_quirk(struct pci_dev *dev)
 	dev->class = PCI_CLASS_BRIDGE_PCI << 8;
 			DEV_PCIE_PORT_0, bridge_class_quirk);
 			DEV_PCIE_PORT_1, bridge_class_quirk);
 			DEV_PCIE_PORT_2, bridge_class_quirk);
 static void system_bus_quirk(struct pci_dev *pdev)

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2020-07-17 10:28 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-16  2:19 [PATCH v3] PCI: loongson: Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk() Tiezhu Yang
2020-07-16  2:21 ` Huacai Chen
2020-07-16  2:37   ` Tiezhu Yang
2020-07-17 10:28 ` Lorenzo Pieralisi

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