160 lines
4.1 KiB
C
160 lines
4.1 KiB
C
/*
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* arch/sh/boards/mach-x3proto/ilsel.c
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*
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* Helper routines for SH-X3 proto board ILSEL.
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*
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* Copyright (C) 2007 - 2010 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bitmap.h>
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#include <linux/io.h>
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#include <mach/ilsel.h>
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/*
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* ILSEL is split across:
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*
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* ILSEL0 - 0xb8100004 [ Levels 1 - 4 ]
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* ILSEL1 - 0xb8100006 [ Levels 5 - 8 ]
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* ILSEL2 - 0xb8100008 [ Levels 9 - 12 ]
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* ILSEL3 - 0xb810000a [ Levels 13 - 15 ]
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*
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* With each level being relative to an ilsel_source_t.
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*/
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#define ILSEL_BASE 0xb8100004
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#define ILSEL_LEVELS 15
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/*
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* ILSEL level map, in descending order from the highest level down.
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*
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* Supported levels are 1 - 15 spread across ILSEL0 - ILSEL4, mapping
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* directly to IRLs. As the IRQs are numbered in reverse order relative
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* to the interrupt level, the level map is carefully managed to ensure a
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* 1:1 mapping between the bit position and the IRQ number.
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*
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* This careful constructions allows ilsel_enable*() to be referenced
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* directly for hooking up an ILSEL set and getting back an IRQ which can
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* subsequently be used for internal accounting in the (optional) disable
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* path.
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*/
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static unsigned long ilsel_level_map;
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static inline unsigned int ilsel_offset(unsigned int bit)
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{
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return ILSEL_LEVELS - bit - 1;
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}
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static inline unsigned long mk_ilsel_addr(unsigned int bit)
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{
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return ILSEL_BASE + ((ilsel_offset(bit) >> 1) & ~0x1);
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}
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static inline unsigned int mk_ilsel_shift(unsigned int bit)
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{
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return (ilsel_offset(bit) & 0x3) << 2;
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}
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static void __ilsel_enable(ilsel_source_t set, unsigned int bit)
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{
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unsigned int tmp, shift;
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unsigned long addr;
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pr_notice("enabling ILSEL set %d\n", set);
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addr = mk_ilsel_addr(bit);
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shift = mk_ilsel_shift(bit);
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pr_debug("%s: bit#%d: addr - 0x%08lx (shift %d, set %d)\n",
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__func__, bit, addr, shift, set);
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tmp = __raw_readw(addr);
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tmp &= ~(0xf << shift);
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tmp |= set << shift;
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__raw_writew(tmp, addr);
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}
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/**
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* ilsel_enable - Enable an ILSEL set.
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* @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
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*
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* Enables a given non-aliased ILSEL source (<= ILSEL_KEY) at the highest
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* available interrupt level. Callers should take care to order callsites
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* noting descending interrupt levels. Aliasing FPGA and external board
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* IRQs need to use ilsel_enable_fixed().
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*
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* The return value is an IRQ number that can later be taken down with
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* ilsel_disable().
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*/
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int ilsel_enable(ilsel_source_t set)
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{
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unsigned int bit;
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if (unlikely(set > ILSEL_KEY)) {
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pr_err("Aliased sources must use ilsel_enable_fixed()\n");
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return -EINVAL;
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}
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do {
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bit = find_first_zero_bit(&ilsel_level_map, ILSEL_LEVELS);
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} while (test_and_set_bit(bit, &ilsel_level_map));
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__ilsel_enable(set, bit);
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return bit;
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}
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EXPORT_SYMBOL_GPL(ilsel_enable);
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/**
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* ilsel_enable_fixed - Enable an ILSEL set at a fixed interrupt level
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* @set: ILSEL source (see ilsel_source_t enum in include/asm-sh/ilsel.h).
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* @level: Interrupt level (1 - 15)
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*
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* Enables a given ILSEL source at a fixed interrupt level. Necessary
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* both for level reservation as well as for aliased sources that only
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* exist on special ILSEL#s.
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*
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* Returns an IRQ number (as ilsel_enable()).
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*/
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int ilsel_enable_fixed(ilsel_source_t set, unsigned int level)
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{
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unsigned int bit = ilsel_offset(level - 1);
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if (test_and_set_bit(bit, &ilsel_level_map))
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return -EBUSY;
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__ilsel_enable(set, bit);
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return bit;
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}
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EXPORT_SYMBOL_GPL(ilsel_enable_fixed);
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/**
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* ilsel_disable - Disable an ILSEL set
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* @irq: Bit position for ILSEL set value (retval from enable routines)
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*
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* Disable a previously enabled ILSEL set.
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*/
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void ilsel_disable(unsigned int irq)
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{
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unsigned long addr;
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unsigned int tmp;
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pr_notice("disabling ILSEL set %d\n", irq);
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addr = mk_ilsel_addr(irq);
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tmp = __raw_readw(addr);
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tmp &= ~(0xf << mk_ilsel_shift(irq));
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__raw_writew(tmp, addr);
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clear_bit(irq, &ilsel_level_map);
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}
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EXPORT_SYMBOL_GPL(ilsel_disable);
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