LXR linux/arch/sh/boards/mach-x3proto/ilsel.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * arch/sh/boards/mach-x3proto/ilsel.c
   4 *
   5 * Helper routines for SH-X3 proto board ILSEL.
   6 *
   7 * Copyright (C) 2007 - 2010  Paul Mundt
   8 */
   9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10
  11#include <linux/init.h>
  12#include <linux/kernel.h>
  13#include <linux/module.h>
  14#include <linux/bitmap.h>
  15#include <linux/io.h>
  16#include <mach/ilsel.h>
  17
  18/*
  19 * ILSEL is split across:
  20 *
  21 *      ILSEL0 - 0xb8100004 [ Levels  1 -  4 ]
  22 *      ILSEL1 - 0xb8100006 [ Levels  5 -  8 ]
  23 *      ILSEL2 - 0xb8100008 [ Levels  9 - 12 ]
  24 *      ILSEL3 - 0xb810000a [ Levels 13 - 15 ]
  25 *
  26 * With each level being relative to an ilsel_source_t.
  27 */
  28#define ILSEL_BASE      0xb8100004
  29#define ILSEL_LEVELS    15
  30
  31/*
  32 * ILSEL level map, in descending order from the highest level down.
  33 *
  34 * Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping
  35 * directly to IRLs. As the IRQs are numbered in reverse order relative
  36 * to the interrupt level, the level map is carefully managed to ensure a
  37 * 1:1 mapping between the bit position and the IRQ number.
  38 *
  39 * This careful constructions allows ilsel_enable*() to be referenced
  40 * directly for hooking up an ILSEL set and getting back an IRQ which can
  41 * subsequently be used for internal accounting in the (optional) disable
  42 * path.
  43 */
  44static unsigned long ilsel_level_map;
  45
  46static inline unsigned int ilsel_offset(unsigned int bit)
  47{
  48        return ILSEL_LEVELS - bit - 1;
  49}
  50
  51static inline unsigned long mk_ilsel_addr(unsigned int bit)
  52{
  53        return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1);
  54}
  55
  56static inline unsigned int mk_ilsel_shift(unsigned int bit)
  57{
  58        return (ilsel_offset(bit) & 0x3) << 2;
  59}
  60
  61static void __ilsel_enable(ilsel_source_t set, unsigned int bit)
  62{
  63        unsigned int tmp, shift;
  64        unsigned long addr;
  65
  66        pr_notice("enabling ILSEL set %d\n", set);
  67
  68        addr = mk_ilsel_addr(bit);
  69        shift = mk_ilsel_shift(bit);
  70
  71        pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n",
  72                 __func__, bit, addr, shift, set);
  73
  74        tmp = __raw_readw(addr);
  75        tmp &= ~(0xf << shift);
  76        tmp |= set << shift;
  77        __raw_writew(tmp, addr);
  78}
  79
  80/**
  81 * ilsel_enable - Enable an ILSEL set.
  82 * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
  83 *
  84 * Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest
  85 * available interrupt level. Callers should take care to order callsites
  86 * noting descending interrupt levels. Aliasing FPGA and external board
  87 * IRQs need to use ilsel_enable_fixed().
  88 *
  89 * The return value is an IRQ number that can later be taken down with
  90 * ilsel_disable().
  91 */
  92int ilsel_enable(ilsel_source_t set)
  93{
  94        unsigned int bit;
  95
  96        if (unlikely(set > ILSEL_KEY)) {
  97                pr_err("Aliased sources must use ilsel_enable_fixed()\n");
  98                return -EINVAL;
  99        }
 100
 101        do {
 102                bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS);
 103        } while (test_and_set_bit(bit, &ilsel_level_map));
 104
 105        __ilsel_enable(set, bit);
 106
 107        return bit;
 108}
 109EXPORT_SYMBOL_GPL(ilsel_enable);
 110
 111/**
 112 * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level
 113 * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
 114 * @level: Interrupt level (1 - 15)
 115 *
 116 * Enables a given ILSEL source at a fixed interrupt level. Necessary
 117 * both for level reservation as well as for aliased sources that only
 118 * exist on special ILSEL#s.
 119 *
 120 * Returns an IRQ number (as ilsel_enable()).
 121 */
 122int ilsel_enable_fixed(ilsel_source_t set, unsigned int level)
 123{
 124        unsigned int bit = ilsel_offset(level - 1);
 125
 126        if (test_and_set_bit(bit, &ilsel_level_map))
 127                return -EBUSY;
 128
 129        __ilsel_enable(set, bit);
 130
 131        return bit;
 132}
 133EXPORT_SYMBOL_GPL(ilsel_enable_fixed);
 134
 135/**
 136 * ilsel_disable - Disable an ILSEL set
 137 * @irq: Bit position for ILSEL set value (retval from enable routines)
 138 *
 139 * Disable a previously enabled ILSEL set.
 140 */
 141void ilsel_disable(unsigned int irq)
 142{
 143        unsigned long addr;
 144        unsigned int tmp;
 145
 146        pr_notice("disabling ILSEL set %d\n", irq);
 147
 148        addr = mk_ilsel_addr(irq);
 149
 150        tmp = __raw_readw(addr);
 151        tmp &= ~(0xf << mk_ilsel_shift(irq));
 152        __raw_writew(tmp, addr);
 153
 154        clear_bit(irq, &ilsel_level_map);
 155}
 156EXPORT_SYMBOL_GPL(ilsel_disable);
 157