From: Pali Roh�r pali@kernel.org
commit 9319230ac147067652b58fe849ffe0ceec098665 upstream.
The current assignment to the class_revision member
class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16);
can make the reader think that class is at high 16 bits of the member and revision at low 16 bits.
In reality, class is at high 24 bits, but the class for PCI Bridge Normal Decode is PCI_CLASS_BRIDGE_PCI << 8.
Change the assignment and add a comment to make this clearer.
Link: https://lore.kernel.org/r/20211130172913.9727-2-kabel@kernel.org Signed-off-by: Pali Roh�r pali@kernel.org Signed-off-by: Marek Beh�n kabel@kernel.org Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Signed-off-by: Marek Beh�n kabel@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/pci/pci-bridge-emul.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
--- a/drivers/pci/pci-bridge-emul.c +++ b/drivers/pci/pci-bridge-emul.c @@ -284,7 +284,11 @@ int pci_bridge_emul_init(struct pci_brid { BUILD_BUG_ON(sizeof(bridge->conf) != PCI_BRIDGE_CONF_END);
- bridge->conf.class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16); + /* + * class_revision: Class is high 24 bits and revision is low 8 bit of this member, + * while class for PCI Bridge Normal Decode has the 24-bit value: PCI_CLASS_BRIDGE_PCI << 8 + */ + bridge->conf.class_revision |= cpu_to_le32((PCI_CLASS_BRIDGE_PCI << 8) << 8); bridge->conf.header_type = PCI_HEADER_TYPE_BRIDGE; bridge->conf.cache_line_size = 0x10; bridge->conf.status = cpu_to_le16(PCI_STATUS_CAP_LIST);