// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2017 Linaro Ltd.
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * 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.
 *
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/of.h>

#define GLOBAL_WORD_ID                          0x00
#define GEMINI_GLOBAL_ARB1_CTRL                 0x2c
#define GEMINI_ARB1_BURST_MASK                  GENMASK(21, 16)
#define GEMINI_ARB1_BURST_SHIFT                 16
/* These all define the priority on the BUS2 backplane */
#define GEMINI_ARB1_PRIO_MASK                   GENMASK(9, 0)
#define GEMINI_ARB1_DMAC_HIGH_PRIO              BIT(0)
#define GEMINI_ARB1_IDE_HIGH_PRIO               BIT(1)
#define GEMINI_ARB1_RAID_HIGH_PRIO              BIT(2)
#define GEMINI_ARB1_SECURITY_HIGH_PRIO          BIT(3)
#define GEMINI_ARB1_GMAC0_HIGH_PRIO             BIT(4)
#define GEMINI_ARB1_GMAC1_HIGH_PRIO             BIT(5)
#define GEMINI_ARB1_USB0_HIGH_PRIO              BIT(6)
#define GEMINI_ARB1_USB1_HIGH_PRIO              BIT(7)
#define GEMINI_ARB1_PCI_HIGH_PRIO               BIT(8)
#define GEMINI_ARB1_TVE_HIGH_PRIO               BIT(9)

#define GEMINI_DEFAULT_BURST_SIZE               0x20
#define GEMINI_DEFAULT_PRIO                     (GEMINI_ARB1_GMAC0_HIGH_PRIO | \
                                                 GEMINI_ARB1_GMAC1_HIGH_PRIO)

static int __init gemini_soc_init(void)
{
        struct regmap *map;
        u32 rev;
        u32 val;
        int ret;

        /* Multiplatform guard, only proceed on Gemini */
        if (!of_machine_is_compatible("cortina,gemini"))
                return 0;

        map = syscon_regmap_lookup_by_compatible("cortina,gemini-syscon");
        if (IS_ERR(map))
                return PTR_ERR(map);
        ret = regmap_read(map, GLOBAL_WORD_ID, &rev);
        if (ret)
                return ret;

        val = (GEMINI_DEFAULT_BURST_SIZE << GEMINI_ARB1_BURST_SHIFT) |
                GEMINI_DEFAULT_PRIO;

        /* Set up system arbitration */
        regmap_update_bits(map,
                           GEMINI_GLOBAL_ARB1_CTRL,
                           GEMINI_ARB1_BURST_MASK | GEMINI_ARB1_PRIO_MASK,
                           val);

        pr_info("Gemini SoC %04x revision %02x, set arbitration %08x\n",
                rev >> 8, rev & 0xff, val);

        return 0;
}
subsys_initcall(gemini_soc_init);