1 /* 2 * arch/sh/boards/mach-x3proto/ilsel.c 3 * 4 * Helper routines for SH-X3 proto board ILSEL. 5 * 6 * Copyright (C) 2007 - 2010 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/bitmap.h> 18 #include <linux/io.h> 19 #include <mach/ilsel.h> 20 21 /* 22 * ILSEL is split across: 23 * 24 * ILSEL0 - 0xb8100004 [ Levels 1 - 4 ] 25 * ILSEL1 - 0xb8100006 [ Levels 5 - 8 ] 26 * ILSEL2 - 0xb8100008 [ Levels 9 - 12 ] 27 * ILSEL3 - 0xb810000a [ Levels 13 - 15 ] 28 * 29 * With each level being relative to an ilsel_source_t. 30 */ 31 #define ILSEL_BASE 0xb8100004 32 #define ILSEL_LEVELS 15 33 34 /* 35 * ILSEL level map, in descending order from the highest level down. 36 * 37 * Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping 38 * directly to IRLs. As the IRQs are numbered in reverse order relative 39 * to the interrupt level, the level map is carefully managed to ensure a 40 * 1:1 mapping between the bit position and the IRQ number. 41 * 42 * This careful constructions allows ilsel_enable*() to be referenced 43 * directly for hooking up an ILSEL set and getting back an IRQ which can 44 * subsequently be used for internal accounting in the (optional) disable 45 * path. 46 */ 47 static unsigned long ilsel_level_map; 48 49 static inline unsigned int ilsel_offset(unsigned int bit) 50 { 51 return ILSEL_LEVELS - bit - 1; 52 } 53 54 static inline unsigned long mk_ilsel_addr(unsigned int bit) 55 { 56 return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1); 57 } 58 59 static inline unsigned int mk_ilsel_shift(unsigned int bit) 60 { 61 return (ilsel_offset(bit) & 0x3) << 2; 62 } 63 64 static void __ilsel_enable(ilsel_source_t set, unsigned int bit) 65 { 66 unsigned int tmp, shift; 67 unsigned long addr; 68 69 pr_notice("enabling ILSEL set %d\n", set); 70 71 addr = mk_ilsel_addr(bit); 72 shift = mk_ilsel_shift(bit); 73 74 pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n", 75 __func__, bit, addr, shift, set); 76 77 tmp = __raw_readw(addr); 78 tmp &= ~(0xf << shift); 79 tmp |= set << shift; 80 __raw_writew(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 if (unlikely(set > ILSEL_KEY)) { 100 pr_err("Aliased sources must use ilsel_enable_fixed()\n"); 101 return -EINVAL; 102 } 103 104 do { 105 bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS); 106 } while (test_and_set_bit(bit, &ilsel_level_map)); 107 108 __ilsel_enable(set, bit); 109 110 return bit; 111 } 112 EXPORT_SYMBOL_GPL(ilsel_enable); 113 114 /** 115 * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level 116 * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h). 117 * @level: Interrupt level (1 - 15) 118 * 119 * Enables a given ILSEL source at a fixed interrupt level. Necessary 120 * both for level reservation as well as for aliased sources that only 121 * exist on special ILSEL#s. 122 * 123 * Returns an IRQ number (as ilsel_enable()). 124 */ 125 int ilsel_enable_fixed(ilsel_source_t set, unsigned int level) 126 { 127 unsigned int bit = ilsel_offset(level - 1); 128 129 if (test_and_set_bit(bit, &ilsel_level_map)) 130 return -EBUSY; 131 132 __ilsel_enable(set, bit); 133 134 return bit; 135 } 136 EXPORT_SYMBOL_GPL(ilsel_enable_fixed); 137 138 /** 139 * ilsel_disable - Disable an ILSEL set 140 * @irq: Bit position for ILSEL set value (retval from enable routines) 141 * 142 * Disable a previously enabled ILSEL set. 143 */ 144 void ilsel_disable(unsigned int irq) 145 { 146 unsigned long addr; 147 unsigned int tmp; 148 149 pr_notice("disabling ILSEL set %d\n", irq); 150 151 addr = mk_ilsel_addr(irq); 152 153 tmp = __raw_readw(addr); 154 tmp &= ~(0xf << mk_ilsel_shift(irq)); 155 __raw_writew(tmp, addr); 156 157 clear_bit(irq, &ilsel_level_map); 158 } 159 EXPORT_SYMBOL_GPL(ilsel_disable); 160