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
  39 static 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 }
  71 subsys_initcall(gemini_soc_init);