common.c

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/*
 * Copyright (c) 2011 Picochip Ltd., Jamie Iles
 *
 * 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.
 *
 * All enquiries to [email protected]
 */
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/dw_apb_timer.h>

#include <asm/mach/arch.h>
#include <asm/hardware/vic.h>
#include <asm/mach/map.h>

#include "common.h"

#define PHYS_TO_IO(x)           (((x) & 0x00ffffff) | 0xfe000000)
#define PICOXCELL_PERIPH_BASE       0x80000000
#define PICOXCELL_PERIPH_LENGTH     SZ_4M

#define WDT_CTRL_REG_EN_MASK        (1 << 0)
#define WDT_CTRL_REG_OFFS       (0x00)
#define WDT_TIMEOUT_REG_OFFS        (0x04)
static void __iomem *wdt_regs;

/*
 * The machine restart method can be called from an atomic context so we won't
 * be able to ioremap the regs then.
 */
static void picoxcell_setup_restart(void)
{
    struct device_node *np = of_find_compatible_node(NULL, NULL,
                             "snps,dw-apb-wdg");
    if (WARN(!np, "unable to setup watchdog restart"))
        return;

    wdt_regs = of_iomap(np, 0);
    WARN(!wdt_regs, "failed to remap watchdog regs");
}

static struct map_desc io_map __initdata = {
    .virtual    = PHYS_TO_IO(PICOXCELL_PERIPH_BASE),
    .pfn        = __phys_to_pfn(PICOXCELL_PERIPH_BASE),
    .length     = PICOXCELL_PERIPH_LENGTH,
    .type       = MT_DEVICE,
};

static void __init picoxcell_map_io(void)
{
    iotable_init(&io_map, 1);
}

static void __init picoxcell_init_machine(void)
{
    of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
    picoxcell_setup_restart();
}

static const char *picoxcell_dt_match[] = {
    "picochip,pc3x2",
    "picochip,pc3x3",
    NULL
};

static const struct of_device_id vic_of_match[] __initconst = {
    { .compatible = "arm,pl192-vic", .data = vic_of_init, },
    { /* Sentinel */ }
};

static void __init picoxcell_init_irq(void)
{
    of_irq_init(vic_of_match);
}

static void picoxcell_wdt_restart(char mode, const char *cmd)
{
    /*
     * Configure the watchdog to reset with the shortest possible timeout
     * and give it chance to do the reset.
     */
    if (wdt_regs) {
        writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
        writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
        /* No sleeping, possibly atomic. */
        mdelay(500);
    }
}

DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
    .map_io     = picoxcell_map_io,
    .nr_irqs    = NR_IRQS_LEGACY,
    .init_irq   = picoxcell_init_irq,
    .handle_irq = vic_handle_irq,
    .timer      = &dw_apb_timer,
    .init_machine   = picoxcell_init_machine,
    .dt_compat  = picoxcell_dt_match,
    .restart    = picoxcell_wdt_restart,
MACHINE_END