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