LXR linux/drivers/soc/gemini/soc-gemini.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright (C) 2017 Linaro Ltd.
   4 *
   5 * Author: Linus Walleij <linus.walleij@linaro.org>
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2, as
   9 * published by the Free Software Foundation.
  10 *
  11 */
  12#include <linux/init.h>
  13#include <linux/kernel.h>
  14#include <linux/mfd/syscon.h>
  15#include <linux/regmap.h>
  16#include <linux/of.h>
  17
  18#define GLOBAL_WORD_ID                          0x00
  19#define GEMINI_GLOBAL_ARB1_CTRL                 0x2c
  20#define GEMINI_ARB1_BURST_MASK                  GENMASK(21, 16)
  21#define GEMINI_ARB1_BURST_SHIFT                 16
  22/* These all define the priority on the BUS2 backplane */
  23#define GEMINI_ARB1_PRIO_MASK                   GENMASK(9, 0)
  24#define GEMINI_ARB1_DMAC_HIGH_PRIO              BIT(0)
  25#define GEMINI_ARB1_IDE_HIGH_PRIO               BIT(1)
  26#define GEMINI_ARB1_RAID_HIGH_PRIO              BIT(2)
  27#define GEMINI_ARB1_SECURITY_HIGH_PRIO          BIT(3)
  28#define GEMINI_ARB1_GMAC0_HIGH_PRIO             BIT(4)
  29#define GEMINI_ARB1_GMAC1_HIGH_PRIO             BIT(5)
  30#define GEMINI_ARB1_USB0_HIGH_PRIO              BIT(6)
  31#define GEMINI_ARB1_USB1_HIGH_PRIO              BIT(7)
  32#define GEMINI_ARB1_PCI_HIGH_PRIO               BIT(8)
  33#define GEMINI_ARB1_TVE_HIGH_PRIO               BIT(9)
  34
  35#define GEMINI_DEFAULT_BURST_SIZE               0x20
  36#define GEMINI_DEFAULT_PRIO                     (GEMINI_ARB1_GMAC0_HIGH_PRIO | \
  37                                                 GEMINI_ARB1_GMAC1_HIGH_PRIO)
  38
  39static int __init gemini_soc_init(void)
  40{
  41        struct regmap *map;
  42        u32 rev;
  43        u32 val;
  44        int ret;
  45
  46        /* Multiplatform guard, only proceed on Gemini */
  47        if (!of_machine_is_compatible("cortina,gemini"))
  48                return 0;
  49
  50        map = syscon_regmap_lookup_by_compatible("cortina,gemini-syscon");
  51        if (IS_ERR(map))
  52                return PTR_ERR(map);
  53        ret = regmap_read(map, GLOBAL_WORD_ID, &rev);
  54        if (ret)
  55                return ret;
  56
  57        val = (GEMINI_DEFAULT_BURST_SIZE << GEMINI_ARB1_BURST_SHIFT) |
  58                GEMINI_DEFAULT_PRIO;
  59
  60        /* Set up system arbitration */
  61        regmap_update_bits(map,
  62                           GEMINI_GLOBAL_ARB1_CTRL,
  63                           GEMINI_ARB1_BURST_MASK | GEMINI_ARB1_PRIO_MASK,
  64                           val);
  65
  66        pr_info("Gemini SoC %04x revision %02x, set arbitration %08x\n",
  67                rev >> 8, rev & 0xff, val);
  68
  69        return 0;
  70}
  71subsys_initcall(gemini_soc_init);
  72