From 84e1b4045dc887b78bdc87d92927093dc3a465aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pali=20Roh=C3=A1r?= <pali@kernel.org>
Date: Thu, 28 Oct 2021 20:56:57 +0200
Subject: [PATCH] PCI: aardvark: Set PCI Bridge Class Code to PCI Bridge
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Git-commit: 84e1b4045dc887b78bdc87d92927093dc3a465aa
Patch-mainline: v5.16-rc1
References: git-fixes stable-5.14.19
Aardvark controller has something like config space of a Root Port
available at offset 0x0 of internal registers - these registers are used
for implementation of the emulated bridge.
The default value of Class Code of this bridge corresponds to a RAID Mass
storage controller, though. (This is probably intended for when the
controller is used as Endpoint.)
Change the Class Code to correspond to a PCI Bridge.
Add comment explaining this change.
Link: https://lore.kernel.org/r/20211028185659.20329-6-kabel@kernel.org
Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: stable@vger.kernel.org
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/pci/controller/pci-aardvark.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index d7db03da4d1c..ddca45415c65 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -511,6 +511,26 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie)
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);
--
2.26.2