PCI: iproc: Add Broadcom iProc PCIe support

Add support for the Broadcom iProc PCIe controller.

pcie-iproc.c is the common core driver, and a front-end bus interface needs
to be added to support different bus interfaces.

pcie-iproc-platform.c contains the support for the platform bus interface.

Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/pci/host/pcie-iproc.c b/drivers/pci/host/pcie-iproc.c
new file mode 100644
index 0000000..329e1b5
--- /dev/null
+++ b/drivers/pci/host/pcie-iproc.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright (C) 2014 Hauke Mehrtens <hauke@hauke-m.de>
+ * Copyright (C) 2015 Broadcom Corporatcommon ion
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/msi.h>
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/mbus.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of_pci.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/phy/phy.h>
+
+#include "pcie-iproc.h"
+
+#define CLK_CONTROL_OFFSET           0x000
+#define EP_MODE_SURVIVE_PERST_SHIFT  1
+#define EP_MODE_SURVIVE_PERST        BIT(EP_MODE_SURVIVE_PERST_SHIFT)
+#define RC_PCIE_RST_OUTPUT_SHIFT     0
+#define RC_PCIE_RST_OUTPUT           BIT(RC_PCIE_RST_OUTPUT_SHIFT)
+
+#define CFG_IND_ADDR_OFFSET          0x120
+#define CFG_IND_ADDR_MASK            0x00001ffc
+
+#define CFG_IND_DATA_OFFSET          0x124
+
+#define CFG_ADDR_OFFSET              0x1f8
+#define CFG_ADDR_BUS_NUM_SHIFT       20
+#define CFG_ADDR_BUS_NUM_MASK        0x0ff00000
+#define CFG_ADDR_DEV_NUM_SHIFT       15
+#define CFG_ADDR_DEV_NUM_MASK        0x000f8000
+#define CFG_ADDR_FUNC_NUM_SHIFT      12
+#define CFG_ADDR_FUNC_NUM_MASK       0x00007000
+#define CFG_ADDR_REG_NUM_SHIFT       2
+#define CFG_ADDR_REG_NUM_MASK        0x00000ffc
+#define CFG_ADDR_CFG_TYPE_SHIFT      0
+#define CFG_ADDR_CFG_TYPE_MASK       0x00000003
+
+#define CFG_DATA_OFFSET              0x1fc
+
+#define SYS_RC_INTX_EN               0x330
+#define SYS_RC_INTX_MASK             0xf
+
+static inline struct iproc_pcie *sys_to_pcie(struct pci_sys_data *sys)
+{
+	return sys->private_data;
+}
+
+/**
+ * Note access to the configuration registers are protected at the higher layer
+ * by 'pci_lock' in drivers/pci/access.c
+ */
+static void __iomem *iproc_pcie_map_cfg_bus(struct pci_bus *bus,
+					    unsigned int devfn,
+					    int where)
+{
+	struct pci_sys_data *sys = bus->sysdata;
+	struct iproc_pcie *pcie = sys_to_pcie(sys);
+	unsigned slot = PCI_SLOT(devfn);
+	unsigned fn = PCI_FUNC(devfn);
+	unsigned busno = bus->number;
+	u32 val;
+
+	/* root complex access */
+	if (busno == 0) {
+		if (slot >= 1)
+			return NULL;
+		writel(where & CFG_IND_ADDR_MASK,
+		       pcie->base + CFG_IND_ADDR_OFFSET);
+		return (pcie->base + CFG_IND_DATA_OFFSET);
+	}
+
+	if (fn > 1)
+		return NULL;
+
+	/* EP device access */
+	val = (busno << CFG_ADDR_BUS_NUM_SHIFT) |
+		(slot << CFG_ADDR_DEV_NUM_SHIFT) |
+		(fn << CFG_ADDR_FUNC_NUM_SHIFT) |
+		(where & CFG_ADDR_REG_NUM_MASK) |
+		(1 & CFG_ADDR_CFG_TYPE_MASK);
+	writel(val, pcie->base + CFG_ADDR_OFFSET);
+
+	return (pcie->base + CFG_DATA_OFFSET);
+}
+
+static struct pci_ops iproc_pcie_ops = {
+	.map_bus = iproc_pcie_map_cfg_bus,
+	.read = pci_generic_config_read32,
+	.write = pci_generic_config_write32,
+};
+
+static void iproc_pcie_reset(struct iproc_pcie *pcie)
+{
+	u32 val;
+
+	/*
+	 * Configure the PCIe controller as root complex and send a downstream
+	 * reset
+	 */
+	val = EP_MODE_SURVIVE_PERST | RC_PCIE_RST_OUTPUT;
+	writel(val, pcie->base + CLK_CONTROL_OFFSET);
+	udelay(250);
+	val &= ~EP_MODE_SURVIVE_PERST;
+	writel(val, pcie->base + CLK_CONTROL_OFFSET);
+	msleep(250);
+}
+
+static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)
+{
+	u8 hdr_type;
+	u32 link_ctrl;
+	u16 pos, link_status;
+	int link_is_active = 0;
+
+	/* make sure we are not in EP mode */
+	pci_bus_read_config_byte(bus, 0, PCI_HEADER_TYPE, &hdr_type);
+	if ((hdr_type & 0x7f) != PCI_HEADER_TYPE_BRIDGE) {
+		dev_err(pcie->dev, "in EP mode, hdr=%#02x\n", hdr_type);
+		return -EFAULT;
+	}
+
+	/* force class to PCI_CLASS_BRIDGE_PCI (0x0604) */
+	pci_bus_write_config_word(bus, 0, PCI_CLASS_DEVICE,
+				  PCI_CLASS_BRIDGE_PCI);
+
+	/* check link status to see if link is active */
+	pos = pci_bus_find_capability(bus, 0, PCI_CAP_ID_EXP);
+	pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA, &link_status);
+	if (link_status & PCI_EXP_LNKSTA_NLW)
+		link_is_active = 1;
+
+	if (!link_is_active) {
+		/* try GEN 1 link speed */
+#define PCI_LINK_STATUS_CTRL_2_OFFSET 0x0dc
+#define PCI_TARGET_LINK_SPEED_MASK    0xf
+#define PCI_TARGET_LINK_SPEED_GEN2    0x2
+#define PCI_TARGET_LINK_SPEED_GEN1    0x1
+		pci_bus_read_config_dword(bus, 0,
+					  PCI_LINK_STATUS_CTRL_2_OFFSET,
+					  &link_ctrl);
+		if ((link_ctrl & PCI_TARGET_LINK_SPEED_MASK) ==
+		    PCI_TARGET_LINK_SPEED_GEN2) {
+			link_ctrl &= ~PCI_TARGET_LINK_SPEED_MASK;
+			link_ctrl |= PCI_TARGET_LINK_SPEED_GEN1;
+			pci_bus_write_config_dword(bus, 0,
+					   PCI_LINK_STATUS_CTRL_2_OFFSET,
+					   link_ctrl);
+			msleep(100);
+
+			pos = pci_bus_find_capability(bus, 0, PCI_CAP_ID_EXP);
+			pci_bus_read_config_word(bus, 0, pos + PCI_EXP_LNKSTA,
+						 &link_status);
+			if (link_status & PCI_EXP_LNKSTA_NLW)
+				link_is_active = 1;
+		}
+	}
+
+	dev_info(pcie->dev, "link: %s\n", link_is_active ? "UP" : "DOWN");
+
+	return link_is_active ? 0 : -ENODEV;
+}
+
+static void iproc_pcie_enable(struct iproc_pcie *pcie)
+{
+	writel(SYS_RC_INTX_MASK, pcie->base + SYS_RC_INTX_EN);
+}
+
+int iproc_pcie_setup(struct iproc_pcie *pcie)
+{
+	int ret;
+	struct pci_bus *bus;
+
+	if (!pcie || !pcie->dev || !pcie->base)
+		return -EINVAL;
+
+	if (pcie->phy) {
+		ret = phy_init(pcie->phy);
+		if (ret) {
+			dev_err(pcie->dev, "unable to initialize PCIe PHY\n");
+			return ret;
+		}
+
+		ret = phy_power_on(pcie->phy);
+		if (ret) {
+			dev_err(pcie->dev, "unable to power on PCIe PHY\n");
+			goto err_exit_phy;
+		}
+
+	}
+
+	iproc_pcie_reset(pcie);
+
+	pcie->sysdata.private_data = pcie;
+
+	bus = pci_create_root_bus(pcie->dev, 0, &iproc_pcie_ops,
+				  &pcie->sysdata, pcie->resources);
+	if (!bus) {
+		dev_err(pcie->dev, "unable to create PCI root bus\n");
+		ret = -ENOMEM;
+		goto err_power_off_phy;
+	}
+	pcie->root_bus = bus;
+
+	ret = iproc_pcie_check_link(pcie, bus);
+	if (ret) {
+		dev_err(pcie->dev, "no PCIe EP device detected\n");
+		goto err_rm_root_bus;
+	}
+
+	iproc_pcie_enable(pcie);
+
+	pci_scan_child_bus(bus);
+	pci_assign_unassigned_bus_resources(bus);
+	pci_fixup_irqs(pci_common_swizzle, of_irq_parse_and_map_pci);
+	pci_bus_add_devices(bus);
+
+	return 0;
+
+err_rm_root_bus:
+	pci_stop_root_bus(bus);
+	pci_remove_root_bus(bus);
+
+err_power_off_phy:
+	if (pcie->phy)
+		phy_power_off(pcie->phy);
+err_exit_phy:
+	if (pcie->phy)
+		phy_exit(pcie->phy);
+
+	return ret;
+}
+EXPORT_SYMBOL(iproc_pcie_setup);
+
+int iproc_pcie_remove(struct iproc_pcie *pcie)
+{
+	pci_stop_root_bus(pcie->root_bus);
+	pci_remove_root_bus(pcie->root_bus);
+
+	if (pcie->phy) {
+		phy_power_off(pcie->phy);
+		phy_exit(pcie->phy);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(iproc_pcie_remove);
+
+MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>");
+MODULE_DESCRIPTION("Broadcom iPROC PCIe common driver");
+MODULE_LICENSE("GPL v2");