pci: mvebu: no longer fake the slot location of downstream devices (f4ac9901) · Commits · 戴 / test

By default, the Marvell hardware, for each PCIe interface, exhibits the following devices: * On slot 0, a "Marvell Memory controller", identical on all PCIe interfaces, and which isn't useful when the Marvell SoC is the PCIe root complex (i.e, the normal case when we run Linux on the Marvell SoC). * On slot 1, the real PCIe card connected into the PCIe slot of the board. So, what the Marvell PCIe driver was doing in its PCI-to-PCI bridge emulation is that when the Linux PCI core was trying to access the device in slot 0, we were in fact forwarding the configuration transaction to the device in slot 1. For all other slots, we were telling the Linux PCI core that there was no device connected. However, new versions of bootloaders from Marvell change the default PCIe configuration, and make the real device appear in slot 0, and the "Marvell Memory controller" in slot 1. Therefore, this commit modifies the Marvell PCIe driver to adjust the PCIe hardware configuration to make sure that this behavior (real device in slot 0, "Marvell Memory controller" in slot 1) is the one we'll see regardless of what the bootloader has done. It allows to remove the little hack that was forwarding configuration transactions on slot 0 to slot 1, which is nice. Signed-off-by:

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Acked-by:

Bjorn Helgaas <bhelgaas@google.com> Signed-off-by:

Jason Cooper <jason@lakedaemon.net>

drivers/pci/host/pci-mvebu.c

+15 −4

Original line number	Diff line number	Diff line
		@@ -51,6 +51,7 @@
		#define PCIE_CTRL_X1_MODE 0x0001
		#define PCIE_STAT_OFF 0x1a04
		#define PCIE_STAT_BUS 0xff00
		#define PCIE_STAT_DEV 0x1f0000
		#define PCIE_STAT_LINK_DOWN BIT(0)
		#define PCIE_DEBUG_CTRL 0x1a60
		#define PCIE_DEBUG_SOFT_RESET BIT(20)
		@@ -148,6 +149,16 @@ static void mvebu_pcie_set_local_bus_nr(struct mvebu_pcie_port *port, int nr)
		writel(stat, port->base + PCIE_STAT_OFF);
		}

		static void mvebu_pcie_set_local_dev_nr(struct mvebu_pcie_port *port, int nr)
		{
		u32 stat;

		stat = readl(port->base + PCIE_STAT_OFF);
		stat &= ~PCIE_STAT_DEV;
		stat \|= nr << 16;
		writel(stat, port->base + PCIE_STAT_OFF);
		}

		/*
		* Setup PCIE BARs and Address Decode Wins:
		* BAR[0,2] -> disabled, BAR[1] -> covers all DRAM banks
		@@ -572,8 +583,7 @@ static int mvebu_pcie_wr_conf(struct pci_bus *bus, u32 devfn,

		/* Access the real PCIe interface */
		spin_lock_irqsave(&port->conf_lock, flags);
		ret = mvebu_pcie_hw_wr_conf(port, bus,
		PCI_DEVFN(1, PCI_FUNC(devfn)),
		ret = mvebu_pcie_hw_wr_conf(port, bus, devfn,
		where, size, val);
		spin_unlock_irqrestore(&port->conf_lock, flags);

		@@ -606,8 +616,7 @@ static int mvebu_pcie_rd_conf(struct pci_bus *bus, u32 devfn, int where,

		/* Access the real PCIe interface */
		spin_lock_irqsave(&port->conf_lock, flags);
		ret = mvebu_pcie_hw_rd_conf(port, bus,
		PCI_DEVFN(1, PCI_FUNC(devfn)),
		ret = mvebu_pcie_hw_rd_conf(port, bus, devfn,
		where, size, val);
		spin_unlock_irqrestore(&port->conf_lock, flags);

		@@ -817,6 +826,8 @@ static int __init mvebu_pcie_probe(struct platform_device *pdev)
		continue;
		}

		mvebu_pcie_set_local_dev_nr(port, 1);

		if (mvebu_pcie_link_up(port)) {
		port->haslink = 1;
		dev_info(&pdev->dev, "PCIe%d.%d: link up\n",

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