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/*
 * PCI support for Xilinx plbv46_pci soft-core which can be used on
 * Xilinx Virtex ML410 / ML510 boards.
 *
 * Copyright 2009 Roderick Colenbrander
 * Copyright 2009 Secret Lab Technologies Ltd.
 *
 * The pci bridge fixup code was copied from ppc4xx_pci.c and was written
 * by Benjamin Herrenschmidt.
 * Copyright 2007 Ben. Herrenschmidt <benh@kernel.crashing.org>, IBM Corp.
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/ioport.h>
#include <linux/of.h>
#include <linux/pci.h>
#include <mm/mmu_decl.h>
#include <asm/io.h>
#include <asm/xilinx_pci.h>

#define XPLB_PCI_ADDR 0x10c
#define XPLB_PCI_DATA 0x110
#define XPLB_PCI_BUS  0x114

#define PCI_HOST_ENABLE_CMD PCI_COMMAND_SERR | PCI_COMMAND_PARITY | PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY

static const struct of_device_id xilinx_pci_match[] = {
	{ .compatible = "xlnx,plbv46-pci-1.03.a", },
	{}
};

/**
 * xilinx_pci_fixup_bridge - Block Xilinx PHB configuration.
 */
static void xilinx_pci_fixup_bridge(struct pci_dev *dev)
{
	struct pci_controller *hose;
	int i;

	if (dev->devfn || dev->bus->self)
		return;

	hose = pci_bus_to_host(dev->bus);
	if (!hose)
		return;

	if (!of_match_node(xilinx_pci_match, hose->dn))
		return;

	/* Hide the PCI host BARs from the kernel as their content doesn't
	 * fit well in the resource management
	 */
	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
		dev->resource[i].start = 0;
		dev->resource[i].end = 0;
		dev->resource[i].flags = 0;
	}

	dev_info(&dev->dev, "Hiding Xilinx plb-pci host bridge resources %s\n",
		 pci_name(dev));
}
DECLARE_PCI_FIXUP_HEADER(PCI_ANY_ID, PCI_ANY_ID, xilinx_pci_fixup_bridge);

/**
 * xilinx_pci_exclude_device - Don't do config access for non-root bus
 *
 * This is a hack.  Config access to any bus other than bus 0 does not
 * currently work on the ML510 so we prevent it here.
 */
static int
xilinx_pci_exclude_device(struct pci_controller *hose, u_char bus, u8 devfn)
{
	return (bus != 0);
}

/**
 * xilinx_pci_init - Find and register a Xilinx PCI host bridge
 */
void __init xilinx_pci_init(void)
{
	struct pci_controller *hose;
	struct resource r;
	void __iomem *pci_reg;
	struct device_node *pci_node;

	pci_node = of_find_matching_node(NULL, xilinx_pci_match);
	if(!pci_node)
		return;

	if (of_address_to_resource(pci_node, 0, &r)) {
		pr_err("xilinx-pci: cannot resolve base address\n");
		return;
	}

	hose = pcibios_alloc_controller(pci_node);
	if (!hose) {
		pr_err("xilinx-pci: pcibios_alloc_controller() failed\n");
		return;
	}

	/* Setup config space */
	setup_indirect_pci(hose, r.start + XPLB_PCI_ADDR,
			   r.start + XPLB_PCI_DATA,
			   PPC_INDIRECT_TYPE_SET_CFG_TYPE);

	/* According to the xilinx plbv46_pci documentation the soft-core starts
	 * a self-init when the bus master enable bit is set. Without this bit
	 * set the pci bus can't be scanned.
	 */
	early_write_config_word(hose, 0, 0, PCI_COMMAND, PCI_HOST_ENABLE_CMD);

	/* Set the max latency timer to 255 */
	early_write_config_byte(hose, 0, 0, PCI_LATENCY_TIMER, 0xff);

	/* Set the max bus number to 255 */
	pci_reg = of_iomap(pci_node, 0);
	out_8(pci_reg + XPLB_PCI_BUS, 0xff);
	iounmap(pci_reg);

	/* Nothing past the root bridge is working right now.  By default
	 * exclude config access to anything except bus 0 */
	if (!ppc_md.pci_exclude_device)
		ppc_md.pci_exclude_device = xilinx_pci_exclude_device;

	/* Register the host bridge with the linux kernel! */
	pci_process_bridge_OF_ranges(hose, pci_node, 1);

	pr_info("xilinx-pci: Registered PCI host bridge\n");
}