[PATCH 5.15 152/917] PCI: aardvark: Set PCI Bridge Class Code to PCI Bridge

@@ -560,6 +560,26 @@ static void advk_pcie_setup_hw(struct ad
 	reg = (PCI_VENDOR_ID_MARVELL << 16) | PCI_VENDOR_ID_MARVELL;
 	advk_writel(pcie, reg, VENDOR_ID_REG);
 
+	/*
+	 * Change Class Code of PCI Bridge device to PCI Bridge (0x600400),
+	 * because the default value is Mass storage controller (0x010400).
+	 *
+	 * Note that this Aardvark PCI Bridge does not have compliant Type 1
+	 * Configuration Space and it even cannot be accessed via Aardvark's
+	 * PCI config space access method. Something like config space is
+	 * available in internal Aardvark registers starting at offset 0x0
+	 * and is reported as Type 0. In range 0x10 - 0x34 it has totally
+	 * different registers.
+	 *
+	 * Therefore driver uses emulation of PCI Bridge which emulates
+	 * access to configuration space via internal Aardvark registers or
+	 * emulated configuration buffer.
+	 */
+	reg = advk_readl(pcie, PCIE_CORE_DEV_REV_REG);
+	reg &= ~0xffffff00;
+	reg |= (PCI_CLASS_BRIDGE_PCI << 8) << 8;
+	advk_writel(pcie, reg, PCIE_CORE_DEV_REV_REG);
+
 	/* Disable Root Bridge I/O space, memory space and bus mastering */
 	reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
 	reg &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);