PCI: pci-bridge-emul: Correctly set PCIe capabilities

stable inclusion
from stable-v5.10.94
commit 7aeeb9fe9ca0b9e084c3ac4c1361b188c31fa9f6
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7aeeb9fe9ca0b9e084c3ac4c1361b188c31fa9f6

--------------------------------

commit 1f1050c5 upstream.

Older mvebu hardware provides PCIe Capability structure only in version 1.
New mvebu and aardvark hardware provides it in version 2. So do not force
version to 2 in pci_bridge_emul_init() and rather allow drivers to set
correct version. Drivers need to set version in pcie_conf.cap field without
overwriting PCI_CAP_LIST_ID register. Both drivers (mvebu and aardvark) do
not provide slot support yet, so do not set PCI_EXP_FLAGS_SLOT flag.

Link: https://lore.kernel.org/r/20211124155944.1290-6-pali@kernel.org
Fixes: 23a5fba4 ("PCI: Introduce PCI bridge emulated config space common logic")
Signed-off-by: NPali Rohár <pali@kernel.org>
Signed-off-by: NLorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

drivers/pci/controller/pci-aardvark.c

@@ -879,7 +879,6 @@ advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
 		return PCI_BRIDGE_EMUL_HANDLED;
 	}
 
-	case PCI_CAP_LIST_ID:
 	case PCI_EXP_DEVCAP:
 	case PCI_EXP_DEVCTL:
 		*value = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg);
@@ -960,6 +959,9 @@ static int advk_sw_pci_bridge_init(struct advk_pcie *pcie)
 	/* Support interrupt A for MSI feature */
 	bridge->conf.intpin = PCIE_CORE_INT_A_ASSERT_ENABLE;
 
+	/* Aardvark HW provides PCIe Capability structure in version 2 */
+	bridge->pcie_conf.cap = cpu_to_le16(2);
+
 	/* Indicates supports for Completion Retry Status */
 	bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_CRSVIS);
 

drivers/pci/controller/pci-mvebu.c

@@ -573,6 +573,8 @@ static struct pci_bridge_emul_ops mvebu_pci_bridge_emul_ops = {
 static void mvebu_pci_bridge_emul_init(struct mvebu_pcie_port *port)
 {
 	struct pci_bridge_emul *bridge = &port->bridge;
+	u32 pcie_cap = mvebu_readl(port, PCIE_CAP_PCIEXP);
+	u8 pcie_cap_ver = ((pcie_cap >> 16) & PCI_EXP_FLAGS_VERS);
 
 	bridge->conf.vendor = PCI_VENDOR_ID_MARVELL;
 	bridge->conf.device = mvebu_readl(port, PCIE_DEV_ID_OFF) >> 16;
@@ -585,6 +587,12 @@ static void mvebu_pci_bridge_emul_init(struct mvebu_pcie_port *port)
 		bridge->conf.iolimit = PCI_IO_RANGE_TYPE_32;
 	}
 
+	/*
+	 * Older mvebu hardware provides PCIe Capability structure only in
+	 * version 1. New hardware provides it in version 2.
+	 */
+	bridge->pcie_conf.cap = cpu_to_le16(pcie_cap_ver);
+
 	bridge->has_pcie = true;
 	bridge->data = port;
 	bridge->ops = &mvebu_pci_bridge_emul_ops;

drivers/pci/pci-bridge-emul.c

@@ -297,10 +297,7 @@ int pci_bridge_emul_init(struct pci_bridge_emul *bridge,
 	if (bridge->has_pcie) {
 		bridge->conf.capabilities_pointer = PCI_CAP_PCIE_START;
 		bridge->pcie_conf.cap_id = PCI_CAP_ID_EXP;
-		/* Set PCIe v2, root port, slot support */
-		bridge->pcie_conf.cap =
-			cpu_to_le16(PCI_EXP_TYPE_ROOT_PORT << 4 | 2 |
-				    PCI_EXP_FLAGS_SLOT);
+		bridge->pcie_conf.cap |= cpu_to_le16(PCI_EXP_TYPE_ROOT_PORT << 4);
 		bridge->pcie_cap_regs_behavior =
 			kmemdup(pcie_cap_regs_behavior,
 				sizeof(pcie_cap_regs_behavior),