The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
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 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
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
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);