/*
 * PowerPC 476FPE board specific routines
 *
 * Copyright © 2013 Tony Breeds IBM Corporation
 * Copyright © 2013 Alistair Popple IBM Corporation
 *
 * Based on earlier code:
 *    Matt Porter <mporter@kernel.crashing.org>
 *    Copyright 2002-2005 MontaVista Software Inc.
 *
 *    Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
 *    Copyright (c) 2003-2005 Zultys Technologies
 *
 *    Rewritten and ported to the merged powerpc tree:
 *    Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
 *    Copyright © 2011 David Kliekamp IBM Corporation
 *
 * 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;  either version 2 of the  License, or (at your
 * option) any later version.
 */

#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/rtc.h>

#include <asm/machdep.h>
#include <asm/prom.h>
#include <asm/udbg.h>
#include <asm/time.h>
#include <asm/uic.h>
#include <asm/ppc4xx.h>
#include <asm/mpic.h>
#include <asm/mmu.h>
#include <asm/swiotlb.h>

#include <linux/pci.h>
#include <linux/i2c.h>

static const struct of_device_id ppc47x_of_bus[] __initconst = {
        { .compatible = "ibm,plb4", },
        { .compatible = "ibm,plb6", },
        { .compatible = "ibm,opb", },
        { .compatible = "ibm,ebc", },
        {},
};

/* The EEPROM is missing and the default values are bogus.  This forces USB in
 * to EHCI mode */
static void quirk_ppc_currituck_usb_fixup(struct pci_dev *dev)
{
        if (of_machine_is_compatible("ibm,currituck")) {
                pci_write_config_dword(dev, 0xe0, 0x0114231f);
                pci_write_config_dword(dev, 0xe4, 0x00006c40);
        }
}
DECLARE_PCI_FIXUP_HEADER(0x1033, 0x0035, quirk_ppc_currituck_usb_fixup);

/* Akebono has an AVR microcontroller attached to the I2C bus
 * which is used to power off/reset the system. */

/* AVR I2C Commands */
#define AVR_PWRCTL_CMD (0x26)

/* Flags for the power control I2C commands */
#define AVR_PWRCTL_PWROFF (0x01)
#define AVR_PWRCTL_RESET (0x02)

static struct i2c_client *avr_i2c_client;
static void __noreturn avr_halt_system(int pwrctl_flags)
{
        /* Request the AVR to reset the system */
        i2c_smbus_write_byte_data(avr_i2c_client,
                                  AVR_PWRCTL_CMD, pwrctl_flags);

        /* Wait for system to be reset */
        while (1)
                ;
}

static void avr_power_off_system(void)
{
        avr_halt_system(AVR_PWRCTL_PWROFF);
}

static void __noreturn avr_reset_system(char *cmd)
{
        avr_halt_system(AVR_PWRCTL_RESET);
}

static int avr_probe(struct i2c_client *client,
                            const struct i2c_device_id *id)
{
        avr_i2c_client = client;
        ppc_md.restart = avr_reset_system;
        pm_power_off = avr_power_off_system;
        return 0;
}

static const struct i2c_device_id avr_id[] = {
        { "akebono-avr", 0 },
        { }
};

static struct i2c_driver avr_driver = {
        .driver = {
                .name = "akebono-avr",
        },
        .probe = avr_probe,
        .id_table = avr_id,
};

static int __init ppc47x_device_probe(void)
{
        i2c_add_driver(&avr_driver);
        of_platform_bus_probe(NULL, ppc47x_of_bus, NULL);

        return 0;
}
machine_device_initcall(ppc47x, ppc47x_device_probe);

static void __init ppc47x_init_irq(void)
{
        struct device_node *np;

        /* Find top level interrupt controller */
        for_each_node_with_property(np, "interrupt-controller") {
                if (of_get_property(np, "interrupts", NULL) == NULL)
                        break;
        }
        if (np == NULL)
                panic("Can't find top level interrupt controller");

        /* Check type and do appropriate initialization */
        if (of_device_is_compatible(np, "chrp,open-pic")) {
                /* The MPIC driver will get everything it needs from the
                 * device-tree, just pass 0 to all arguments
                 */
                struct mpic *mpic =
                        mpic_alloc(np, 0, MPIC_NO_RESET, 0, 0, " MPIC     ");
                BUG_ON(mpic == NULL);
                mpic_init(mpic);
                ppc_md.get_irq = mpic_get_irq;
        } else
                panic("Unrecognized top level interrupt controller");
}

#ifdef CONFIG_SMP
static void smp_ppc47x_setup_cpu(int cpu)
{
        mpic_setup_this_cpu();
}

static int smp_ppc47x_kick_cpu(int cpu)
{
        struct device_node *cpunode = of_get_cpu_node(cpu, NULL);
        const u64 *spin_table_addr_prop;
        u32 *spin_table;
        extern void start_secondary_47x(void);

        BUG_ON(cpunode == NULL);

        /* Assume spin table. We could test for the enable-method in
         * the device-tree but currently there's little point as it's
         * our only supported method
         */
        spin_table_addr_prop =
                of_get_property(cpunode, "cpu-release-addr", NULL);

        if (spin_table_addr_prop == NULL) {
                pr_err("CPU%d: Can't start, missing cpu-release-addr !\n",
                       cpu);
                return 1;
        }

        /* Assume it's mapped as part of the linear mapping. This is a bit
         * fishy but will work fine for now
         *
         * XXX: Is there any reason to assume differently?
         */
        spin_table = (u32 *)__va(*spin_table_addr_prop);
        pr_debug("CPU%d: Spin table mapped at %p\n", cpu, spin_table);

        spin_table[3] = cpu;
        smp_wmb();
        spin_table[1] = __pa(start_secondary_47x);
        mb();

        return 0;
}

static struct smp_ops_t ppc47x_smp_ops = {
        .probe          = smp_mpic_probe,
        .message_pass   = smp_mpic_message_pass,
        .setup_cpu      = smp_ppc47x_setup_cpu,
        .kick_cpu       = smp_ppc47x_kick_cpu,
        .give_timebase  = smp_generic_give_timebase,
        .take_timebase  = smp_generic_take_timebase,
};

static void __init ppc47x_smp_init(void)
{
        if (mmu_has_feature(MMU_FTR_TYPE_47x))
                smp_ops = &ppc47x_smp_ops;
}

#else /* CONFIG_SMP */
static void __init ppc47x_smp_init(void) { }
#endif /* CONFIG_SMP */

static void __init ppc47x_setup_arch(void)
{

        /* No need to check the DMA config as we /know/ our windows are all of
         * RAM.  Lets hope that doesn't change */
        swiotlb_detect_4g();

        ppc47x_smp_init();
}

static int board_rev = -1;
static int __init ppc47x_get_board_rev(void)
{
        int reg;
        u8 *fpga;
        struct device_node *np = NULL;

        if (of_machine_is_compatible("ibm,currituck")) {
                np = of_find_compatible_node(NULL, NULL, "ibm,currituck-fpga");
                reg = 0;
        } else if (of_machine_is_compatible("ibm,akebono")) {
                np = of_find_compatible_node(NULL, NULL, "ibm,akebono-fpga");
                reg = 2;
        }

        if (!np)
                goto fail;

        fpga = (u8 *) of_iomap(np, 0);
        of_node_put(np);
        if (!fpga)
                goto fail;

        board_rev = ioread8(fpga + reg) & 0x03;
        pr_info("%s: Found board revision %d\n", __func__, board_rev);
        iounmap(fpga);
        return 0;

fail:
        pr_info("%s: Unable to find board revision\n", __func__);
        return 0;
}
machine_arch_initcall(ppc47x, ppc47x_get_board_rev);

/* Use USB controller should have been hardware swizzled but it wasn't :( */
static void ppc47x_pci_irq_fixup(struct pci_dev *dev)
{
        if (dev->vendor == 0x1033 && (dev->device == 0x0035 ||
                                      dev->device == 0x00e0)) {
                if (board_rev == 0) {
                        dev->irq = irq_create_mapping(NULL, 47);
                        pr_info("%s: Mapping irq %d\n", __func__, dev->irq);
                } else if (board_rev == 2) {
                        dev->irq = irq_create_mapping(NULL, 49);
                        pr_info("%s: Mapping irq %d\n", __func__, dev->irq);
                } else {
                        pr_alert("%s: Unknown board revision\n", __func__);
                }
        }
}

/*
 * Called very early, MMU is off, device-tree isn't unflattened
 */
static int __init ppc47x_probe(void)
{
        if (of_machine_is_compatible("ibm,akebono"))
                return 1;

        if (of_machine_is_compatible("ibm,currituck")) {
                ppc_md.pci_irq_fixup = ppc47x_pci_irq_fixup;
                return 1;
        }

        return 0;
}

define_machine(ppc47x) {
        .name                   = "PowerPC 47x",
        .probe                  = ppc47x_probe,
        .progress               = udbg_progress,
        .init_IRQ               = ppc47x_init_irq,
        .setup_arch             = ppc47x_setup_arch,
        .restart                = ppc4xx_reset_system,
        .calibrate_decr         = generic_calibrate_decr,
};