PCI: mvebu: Add PCI Express root complex capability block

Add a PCI Express root complex capability block so the PCI layer identifies
the bridge as a PCI Express device.

We expose this as a version 1 PCIe capability block, with slot support. We
disable the clock power management capability as this depends on boards
wiring the CLKREQ# signal.

Tested-by: Willy Tarreau <[e-mail]> (Iomega iConnect Kirkwood, MiraBox Armada 370)
Tested-by: Andrew Lunn <[e-mail]> (D-Link DIR664 Kirkwood)
Tested-by: Thomas Petazzoni <[e-mail]> (Armada XP GP)
Signed-off-by: Russell King <[e-mail]>
Signed-off-by: Bjorn Helgaas <[e-mail]>
Reviewed-by: Thomas Petazzoni <[e-mail]>

drivers/pci/host/pci-mvebu.c

···
 #define PCIE_DEV_REV_OFF	0x0008
 #define PCIE_BAR_LO_OFF(n)	(0x0010 + ((n) << 3))
 #define PCIE_BAR_HI_OFF(n)	(0x0014 + ((n) << 3))
+#define PCIE_CAP_PCIEXP		0x0060
 #define PCIE_HEADER_LOG_4_OFF	0x0128
 #define PCIE_BAR_CTRL_OFF(n)	(0x1804 + (((n) - 1) * 4))
 #define PCIE_WIN04_CTRL_OFF(n)	(0x1820 + ((n) << 4))
···
 #define  PCIE_STAT_BUS                  0xff00
 #define  PCIE_STAT_DEV                  0x1f0000
 #define  PCIE_STAT_LINK_DOWN		BIT(0)
+#define PCIE_RC_RTSTA		0x1a14
 #define PCIE_DEBUG_CTRL         0x1a60
 #define  PCIE_DEBUG_SOFT_RESET		BIT(20)
+
+enum {
+	PCISWCAP = PCI_BRIDGE_CONTROL + 2,
+	PCISWCAP_EXP_LIST_ID	= PCISWCAP + PCI_CAP_LIST_ID,
+	PCISWCAP_EXP_DEVCAP	= PCISWCAP + PCI_EXP_DEVCAP,
+	PCISWCAP_EXP_DEVCTL	= PCISWCAP + PCI_EXP_DEVCTL,
+	PCISWCAP_EXP_LNKCAP	= PCISWCAP + PCI_EXP_LNKCAP,
+	PCISWCAP_EXP_LNKCTL	= PCISWCAP + PCI_EXP_LNKCTL,
+	PCISWCAP_EXP_SLTCAP	= PCISWCAP + PCI_EXP_SLTCAP,
+	PCISWCAP_EXP_SLTCTL	= PCISWCAP + PCI_EXP_SLTCTL,
+	PCISWCAP_EXP_RTCTL	= PCISWCAP + PCI_EXP_RTCTL,
+	PCISWCAP_EXP_RTSTA	= PCISWCAP + PCI_EXP_RTSTA,
+	PCISWCAP_EXP_DEVCAP2	= PCISWCAP + PCI_EXP_DEVCAP2,
+	PCISWCAP_EXP_DEVCTL2	= PCISWCAP + PCI_EXP_DEVCTL2,
+	PCISWCAP_EXP_LNKCAP2	= PCISWCAP + PCI_EXP_LNKCAP2,
+	PCISWCAP_EXP_LNKCTL2	= PCISWCAP + PCI_EXP_LNKCTL2,
+	PCISWCAP_EXP_SLTCAP2	= PCISWCAP + PCI_EXP_SLTCAP2,
+	PCISWCAP_EXP_SLTCTL2	= PCISWCAP + PCI_EXP_SLTCTL2,
+};
 
 /* PCI configuration space of a PCI-to-PCI bridge */
 struct mvebu_sw_pci_bridge {
 	u16 vendor;
 	u16 device;
 	u16 command;
+	u16 status;
 	u16 class;
 	u8 interface;
 	u8 revision;
···
 	u16 memlimit;
 	u16 iobaseupper;
 	u16 iolimitupper;
-	u8 cappointer;
-	u8 reserved1;
-	u16 reserved2;
 	u32 romaddr;
 	u8 intline;
 	u8 intpin;
 	u16 bridgectrl;
+
+	/* PCI express capability */
+	u32 pcie_sltcap;
+	u16 pcie_devctl;
+	u16 pcie_rtctl;
 };
 
 struct mvebu_pcie_port;
···
 	/* We support 32 bits I/O addressing */
 	bridge->iobase = PCI_IO_RANGE_TYPE_32;
 	bridge->iolimit = PCI_IO_RANGE_TYPE_32;
+
+	/* Add capabilities */
+	bridge->status = PCI_STATUS_CAP_LIST;
 }
 
 /*
···
 		break;
 
 	case PCI_COMMAND:
-		*value = bridge->command;
+		*value = bridge->command | bridge->status << 16;
 		break;
 
 	case PCI_CLASS_REVISION:
···
 		*value = (bridge->iolimitupper << 16 | bridge->iobaseupper);
 		break;
 
+	case PCI_CAPABILITY_LIST:
+		*value = PCISWCAP;
+		break;
+
 	case PCI_ROM_ADDRESS1:
 		*value = 0;
 		break;
···
 		*value = 0;
 		break;
 
+	case PCISWCAP_EXP_LIST_ID:
+		/* Set PCIe v2, root port, slot support */
+		*value = (PCI_EXP_TYPE_ROOT_PORT << 4 | 2 |
+			  PCI_EXP_FLAGS_SLOT) << 16 | PCI_CAP_ID_EXP;
+		break;
+
+	case PCISWCAP_EXP_DEVCAP:
+		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCAP);
+		break;
+
+	case PCISWCAP_EXP_DEVCTL:
+		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL) &
+				 ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
+				   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
+		*value |= bridge->pcie_devctl;
+		break;
+
+	case PCISWCAP_EXP_LNKCAP:
+		/*
+		 * PCIe requires the clock power management capability to be
+		 * hard-wired to zero for downstream ports
+		 */
+		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCAP) &
+			 ~PCI_EXP_LNKCAP_CLKPM;
+		break;
+
+	case PCISWCAP_EXP_LNKCTL:
+		*value = mvebu_readl(port, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
+		break;
+
+	case PCISWCAP_EXP_SLTCAP:
+		*value = bridge->pcie_sltcap;
+		break;
+
+	case PCISWCAP_EXP_SLTCTL:
+		*value = PCI_EXP_SLTSTA_PDS << 16;
+		break;
+
+	case PCISWCAP_EXP_RTCTL:
+		*value = bridge->pcie_rtctl;
+		break;
+
+	case PCISWCAP_EXP_RTSTA:
+		*value = mvebu_readl(port, PCIE_RC_RTSTA);
+		break;
+
+	/* PCIe requires the v2 fields to be hard-wired to zero */
+	case PCISWCAP_EXP_DEVCAP2:
+	case PCISWCAP_EXP_DEVCTL2:
+	case PCISWCAP_EXP_LNKCAP2:
+	case PCISWCAP_EXP_LNKCTL2:
+	case PCISWCAP_EXP_SLTCAP2:
+	case PCISWCAP_EXP_SLTCTL2:
 	default:
 		/*
 		 * PCI defines configuration read accesses to reserved or
···
 		bridge->subordinate_bus         = (value >> 16) & 0xff;
 		bridge->secondary_latency_timer = (value >> 24) & 0xff;
 		mvebu_pcie_set_local_bus_nr(port, bridge->secondary_bus);
+		break;
+
+	case PCISWCAP_EXP_DEVCTL:
+		/*
+		 * Armada370 data says these bits must always
+		 * be zero when in root complex mode.
+		 */
+		value &= ~(PCI_EXP_DEVCTL_URRE | PCI_EXP_DEVCTL_FERE |
+			   PCI_EXP_DEVCTL_NFERE | PCI_EXP_DEVCTL_CERE);
+
+		/*
+		 * If the mask is 0xffff0000, then we only want to write
+		 * the device control register, rather than clearing the
+		 * RW1C bits in the device status register.  Mask out the
+		 * status register bits.
+		 */
+		if (mask == 0xffff0000)
+			value &= 0xffff;
+
+		mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_DEVCTL);
+		break;
+
+	case PCISWCAP_EXP_LNKCTL:
+		/*
+		 * If we don't support CLKREQ, we must ensure that the
+		 * CLKREQ enable bit always reads zero.  Since we haven't
+		 * had this capability, and it's dependent on board wiring,
+		 * disable it for the time being.
+		 */
+		value &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
+
+		/*
+		 * If the mask is 0xffff0000, then we only want to write
+		 * the link control register, rather than clearing the
+		 * RW1C bits in the link status register.  Mask out the
+		 * status register bits.
+		 */
+		if (mask == 0xffff0000)
+			value &= 0xffff;
+
+		mvebu_writel(port, value, PCIE_CAP_PCIEXP + PCI_EXP_LNKCTL);
+		break;
+
+	case PCISWCAP_EXP_RTSTA:
+		mvebu_writel(port, value, PCIE_RC_RTSTA);
 		break;
 
 	default: