PCI: keystone: Add TI Keystone PCIe driver

The Keystone PCIe controller is based on v3.65 version of the Designware
h/w.  Main differences are:

    1. No ATU support
    2. Legacy and MSI IRQ functions are implemented in application register
       space
    3. MSI interrupts are multiplexed over 8 IRQ lines to the Host side.

All of the application register space handing code is organized into
pci-keystone-dw.c and the functions are called from pci-keystone.c to
implement PCI controller driver.  Also add necessary DT documentation and
update the MAINTAINERS file for the driver.

[bhelgaas: spelling and whitespace fixes]
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Grant Likely <grant.likely@linaro.org>
CC: Rob Herring <robh+dt@kernel.org>
CC: Mohit Kumar <mohit.kumar@st.com>
CC: Pratyush Anand <pratyush.anand@st.com>
CC: Jingoo Han <jg1.han@samsung.com>
CC: Richard Zhu <r65037@freescale.com>
CC: Kishon Vijay Abraham I <kishon@ti.com>
CC: Marek Vasut <marex@denx.de>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Grant Likely <grant.likely@linaro.org>
diff --git a/drivers/pci/host/pci-keystone.h b/drivers/pci/host/pci-keystone.h
new file mode 100644
index 0000000..729ea7d
--- /dev/null
+++ b/drivers/pci/host/pci-keystone.h
@@ -0,0 +1,58 @@
+/*
+ * Keystone PCI Controller's common includes
+ *
+ * Copyright (C) 2013-2014 Texas Instruments., Ltd.
+ *		http://www.ti.com
+ *
+ * Author: Murali Karicheri <m-karicheri2@ti.com>
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#define MAX_LEGACY_IRQS			4
+#define MAX_MSI_HOST_IRQS		8
+#define MAX_LEGACY_HOST_IRQS		4
+
+struct keystone_pcie {
+	struct	clk		*clk;
+	struct	pcie_port	pp;
+	void __iomem		*va_reg_pciid;
+
+	int			num_legacy_host_irqs;
+	int			legacy_host_irqs[MAX_LEGACY_HOST_IRQS];
+	struct			device_node *legacy_intc_np;
+
+	int			num_msi_host_irqs;
+	int			msi_host_irqs[MAX_MSI_HOST_IRQS];
+	struct			device_node *msi_intc_np;
+	struct irq_domain	*legacy_irq_domain;
+
+	/* Application register space */
+	void __iomem		*va_app_base;
+	struct resource		app;
+};
+
+/* Keystone DW specific MSI controller APIs/definitions */
+void ks_dw_pcie_handle_msi_irq(struct keystone_pcie *ks_pcie, int offset);
+u32 ks_dw_pcie_get_msi_data(struct pcie_port *pp);
+
+/* Keystone specific PCI controller APIs */
+void ks_dw_pcie_enable_legacy_irqs(struct keystone_pcie *ks_pcie);
+void ks_dw_pcie_handle_legacy_irq(struct keystone_pcie *ks_pcie, int offset);
+int  ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
+			struct device_node *msi_intc_np);
+int ks_dw_pcie_wr_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+		unsigned int devfn, int where, int size, u32 val);
+int ks_dw_pcie_rd_other_conf(struct pcie_port *pp, struct pci_bus *bus,
+		unsigned int devfn, int where, int size, u32 *val);
+void ks_dw_pcie_setup_rc_app_regs(struct keystone_pcie *ks_pcie);
+int ks_dw_pcie_link_up(struct pcie_port *pp);
+void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie);
+void ks_dw_pcie_msi_set_irq(struct pcie_port *pp, int irq);
+void ks_dw_pcie_msi_clear_irq(struct pcie_port *pp, int irq);
+void ks_dw_pcie_v3_65_scan_bus(struct pcie_port *pp);
+int ks_dw_pcie_msi_host_init(struct pcie_port *pp,
+		struct msi_chip *chip);