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[32/42] PCI: pci-bridge-emul: Add description for class_revision field

Message ID 20210506153153.30454-33-pali@kernel.org
State New
Headers show
Series PCI: aardvark: Various driver fixes | expand

Commit Message

Pali Rohár May 6, 2021, 3:31 p.m. UTC 
Make it clear why there is bitshift by 16 and rewrite the code to align
with the new description.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
---
 drivers/pci/pci-bridge-emul.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
index fdaf86a888b7..2b6ea84f25af 100644
--- a/drivers/pci/pci-bridge-emul.c
+++ b/drivers/pci/pci-bridge-emul.c
@@ -265,7 +265,11 @@  int pci_bridge_emul_init(struct pci_bridge_emul *bridge,
 {
 	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 24bits and revision is low 8bit
+	 * Class for PCI Bridge Normal Decode has 24bit 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);