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 */ 45static unsigned long ilsel_level_map; 46 47static inline unsigned int ilsel_offset(unsigned int bit) 48{ 49 return ILSEL_LEVELS - bit - 1; 50} 51 52static inline unsigned long mk_ilsel_addr(unsigned int bit) 53{ 54 return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1); 55} 56 57static inline unsigned int mk_ilsel_shift(unsigned int bit) 58{ 59 return (ilsel_offset(bit) & 0x3) << 2; 60} 61 62static 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 __func__, bit, addr, shift, set); 72 73 tmp = __raw_readw(addr); 74 tmp &= ~(0xf << shift); 75 tmp |= set << shift; 76 __raw_writew(tmp, addr); 77} 78 79/** 80 * ilsel_enable - Enable an ILSEL set. 81 * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h). 82 * 83 * Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest 84 * available interrupt level. Callers should take care to order callsites 85 * noting descending interrupt levels. Aliasing FPGA and external board 86 * IRQs need to use ilsel_enable_fixed(). 87 * 88 * The return value is an IRQ number that can later be taken down with 89 * ilsel_disable(). 90 */ 91int ilsel_enable(ilsel_source_t set) 92{ 93 unsigned int bit; 94 95 /* Aliased sources must use ilsel_enable_fixed() */ 96 BUG_ON(set > ILSEL_KEY); 97 98 do { 99 bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS); 100 } while (test_and_set_bit(bit, &ilsel_level_map)); 101 102 __ilsel_enable(set, bit); 103 104 return bit; 105} 106EXPORT_SYMBOL_GPL(ilsel_enable); 107 108/** 109 * ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level 110 * @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h). 111 * @level: Interrupt level (1 - 15) 112 * 113 * Enables a given ILSEL source at a fixed interrupt level. Necessary 114 * both for level reservation as well as for aliased sources that only 115 * exist on special ILSEL#s. 116 * 117 * Returns an IRQ number (as ilsel_enable()). 118 */ 119int ilsel_enable_fixed(ilsel_source_t set, unsigned int level) 120{ 121 unsigned int bit = ilsel_offset(level - 1); 122 123 if (test_and_set_bit(bit, &ilsel_level_map)) 124 return -EBUSY; 125 126 __ilsel_enable(set, bit); 127 128 return bit; 129} 130EXPORT_SYMBOL_GPL(ilsel_enable_fixed); 131 132/** 133 * ilsel_disable - Disable an ILSEL set 134 * @irq: Bit position for ILSEL set value (retval from enable routines) 135 * 136 * Disable a previously enabled ILSEL set. 137 */ 138void ilsel_disable(unsigned int irq) 139{ 140 unsigned long addr; 141 unsigned int tmp; 142 143 addr = mk_ilsel_addr(irq); 144 145 tmp = __raw_readw(addr); 146 tmp &= ~(0xf << mk_ilsel_shift(irq)); 147 __raw_writew(tmp, addr); 148 149 clear_bit(irq, &ilsel_level_map); 150} 151EXPORT_SYMBOL_GPL(ilsel_disable); 152