diff options
Diffstat (limited to 'arch/sh/boards/mach-x3proto/ilsel.c')
| -rw-r--r-- | arch/sh/boards/mach-x3proto/ilsel.c | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/arch/sh/boards/mach-x3proto/ilsel.c b/arch/sh/boards/mach-x3proto/ilsel.c new file mode 100644 index 000000000..95e346139 --- /dev/null +++ b/arch/sh/boards/mach-x3proto/ilsel.c @@ -0,0 +1,159 @@ +/* + * arch/sh/boards/mach-x3proto/ilsel.c + * + * Helper routines for SH-X3 proto board ILSEL. + * + * Copyright (C) 2007 - 2010 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. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/bitmap.h> +#include <linux/io.h> +#include <mach/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; + + pr_notice("enabling ILSEL set %d\n", set); + + 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; + + if (unlikely(set > ILSEL_KEY)) { + pr_err("Aliased sources must use ilsel_enable_fixed()\n"); + return -EINVAL; + } + + 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; + + pr_notice("disabling ILSEL set %d\n", irq); + + 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); |