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From: Tiezhu Yang <>
To: Lorenzo Pieralisi <>,
	Rob Herring <>,
	Bjorn Helgaas <>,
	Thomas Bogendoerfer <>,
	Huacai Chen <>,
	Jiaxun Yang <>
Cc:,,, Xuefeng Li <>
Subject: [PATCH v4] PCI: loongson: Use DECLARE_PCI_FIXUP_EARLY for bridge_class_quirk()
Date: Sat, 18 Jul 2020 16:37:04 +0800	[thread overview]
Message-ID: <> (raw)

According to the datasheet of Loongson LS7A bridge chip, the old version
of Loongson LS7A PCIE port has a wrong value about PCI class which is
0x060000, the correct value should be 0x060400, this bug can be fixed by
"dev->class = PCI_CLASS_BRIDGE_PCI << 8;" at the software level. As far
as I know, the latest version of LS7A has already fixed the value at the
hardware level.

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.

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

v4: 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)

             reply	other threads:[~2020-07-18  8:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-18  8:37 Tiezhu Yang [this message]
2020-07-18  8:44 ` Sergei Shtylyov

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