arch/sh/boards/renesas/x3proto/ilsel.c

   1 /*
   2  * arch/sh/boards/renesas/x3proto/ilsel.c
   3  *
   4  * Helper routines for SH-X3 proto board ILSEL.
   5  *
   6  * Copyright (C) 2007 Paul Mundt
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file "COPYING" in the main directory of this archive
  10  * for more details.
  11  */
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/bitmap.h>
  16 #include <linux/io.h>
  17 #include <asm/ilsel.h>
  18
  19 /*
  20  * ILSEL is split across:
  21  *
  22  *      ILSEL0 - 0xb8100004 [ Levels  1 -  4 ]
  23  *      ILSEL1 - 0xb8100006 [ Levels  5 -  8 ]
  24  *      ILSEL2 - 0xb8100008 [ Levels  9 - 12 ]
  25  *      ILSEL3 - 0xb810000a [ Levels 13 - 15 ]
  26  *
  27  * With each level being relative to an ilsel_source_t.
  28  */
  29 #define ILSEL_BASE      0xb8100004
  30 #define ILSEL_LEVELS    15
  31
  32 /*
  33  * ILSEL level map, in descending order from the highest level down.
  34  *
  35  * Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping
  36  * directly to IRLs. As the IRQs are numbered in reverse order relative
  37  * to the interrupt level, the level map is carefully managed to ensure a
  38  * 1:1 mapping between the bit position and the IRQ number.
  39  *
  40  * This careful constructions allows ilsel_enable*() to be referenced
  41  * directly for hooking up an ILSEL set and getting back an IRQ which can
  42  * subsequently be used for internal accounting in the (optional) disable
  43  * path.
  44  */
  45 static unsigned long ilsel_level_map;
  46
  47 static inline unsigned int ilsel_offset(unsigned int bit)
  48 {
  49         return ILSEL_LEVELS - bit - 1;
  50 }
  51
  52 static inline unsigned long mk_ilsel_addr(unsigned int bit)
  53 {
  54         return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1);
  55 }
  56
  57 static inline unsigned int mk_ilsel_shift(unsigned int bit)
  58 {
  59         return (ilsel_offset(bit) & 0x3) << 2;
  60 }
  61
  62 static void __ilsel_enable(ilsel_source_t set, unsigned int bit)
  63 {
  64         unsigned int tmp, shift;
  65         unsigned long addr;
  66
  67         addr = mk_ilsel_addr(bit);
  68         shift = mk_ilsel_shift(bit);
  69
  70         pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n",
  71 <<<<<<< HEAD:arch/sh/boards/renesas/x3proto/ilsel.c
  72                  __FUNCTION__, bit, addr, shift, set);
  73 =======
  74                  __func__, bit, addr, shift, set);
  75 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:arch/sh/boards/renesas/x3proto/ilsel.c
  76
  77         tmp = ctrl_inw(addr);
  78         tmp &= ~(0xf << shift);
  79         tmp |= set << shift;
  80         ctrl_outw(tmp, addr);
  81 }
  82
  83 /**
  84  * ilsel_enable - Enable an ILSEL set.
  85  * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
  86  *
  87  * Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest
  88  * available interrupt level. Callers should take care to order callsites
  89  * noting descending interrupt levels. Aliasing FPGA and external board
  90  * IRQs need to use ilsel_enable_fixed().
  91  *
  92  * The return value is an IRQ number that can later be taken down with
  93  * ilsel_disable().
  94  */
  95 int ilsel_enable(ilsel_source_t set)
  96 {
  97         unsigned int bit;
  98
  99         /* Aliased sources must use ilsel_enable_fixed() */
 100         BUG_ON(set > ILSEL_KEY);
 101
 102         do {
 103                 bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS);
 104         } while (test_and_set_bit(bit, &ilsel_level_map));
 105
 106         __ilsel_enable(set, bit);
 107
 108         return bit;
 109 }
 110 EXPORT_SYMBOL_GPL(ilsel_enable);
 111
 112 /**
 113  * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level
 114  * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
 115  * @level: Interrupt level (1 - 15)
 116  *
 117  * Enables a given ILSEL source at a fixed interrupt level. Necessary
 118  * both for level reservation as well as for aliased sources that only
 119  * exist on special ILSEL#s.
 120  *
 121  * Returns an IRQ number (as ilsel_enable()).
 122  */
 123 int ilsel_enable_fixed(ilsel_source_t set, unsigned int level)
 124 {
 125         unsigned int bit = ilsel_offset(level - 1);
 126
 127         if (test_and_set_bit(bit, &ilsel_level_map))
 128                 return -EBUSY;
 129
 130         __ilsel_enable(set, bit);
 131
 132         return bit;
 133 }
 134 EXPORT_SYMBOL_GPL(ilsel_enable_fixed);
 135
 136 /**
 137  * ilsel_disable - Disable an ILSEL set
 138  * @irq: Bit position for ILSEL set value (retval from enable routines)
 139  *
 140  * Disable a previously enabled ILSEL set.
 141  */
 142 void ilsel_disable(unsigned int irq)
 143 {
 144         unsigned long addr;
 145         unsigned int tmp;
 146
 147         addr = mk_ilsel_addr(irq);
 148
 149         tmp = ctrl_inw(addr);
 150         tmp &= ~(0xf << mk_ilsel_shift(irq));
 151         ctrl_outw(tmp, addr);
 152
 153         clear_bit(irq, &ilsel_level_map);
 154 }
 155 EXPORT_SYMBOL_GPL(ilsel_disable);