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x86, pic: Introduce legacy_pic abstraction

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This patch makes i8259A like legacy programmable interrupt controller
code into a driver so that legacy pic functions can be selected at
runtime based on platform information, such as HW subarchitecure ID.
Default structure of legacy_pic maintains the current code path for
x86pc.

Signed-off-by: Jacob Pan <jacob.jun.pan@intel.com>
LKML-Reference: <43F901BD926A4E43B106BF17856F07559FB80D03@orsmsx508.amr.corp.intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Jacob Pan 2009-11-09 11:24:14 -08:00 committed by H. Peter Anvin
parent 35f720c593
commit ef3548668c
2 changed files with 56 additions and 0 deletions
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13
arch/x86/include/asm/i8259.h
View File

@ -57,6 +57,19 @@ static inline void outb_pic(unsigned char value, unsigned int port)
extern struct irq_chip i8259A_chip;
struct legacy_pic {
int nr_legacy_irqs;
struct irq_chip *chip;
void (*mask_all)(void);
void (*restore_mask)(void);
void (*init)(int auto_eoi);
int (*irq_pending)(unsigned int irq);
void (*make_irq)(unsigned int irq);
};
extern struct legacy_pic *legacy_pic;
extern struct legacy_pic null_legacy_pic;
extern void mask_8259A(void);
extern void unmask_8259A(void);

43
arch/x86/kernel/i8259.c
View File

@ -358,3 +358,46 @@ void init_8259A(int auto_eoi)
spin_unlock_irqrestore(&i8259A_lock, flags);
}
/*
* make i8259 a driver so that we can select pic functions at run time. the goal
* is to make x86 binary compatible among pc compatible and non-pc compatible
* platforms, such as x86 MID.
*/
static void __init legacy_pic_noop(void) { };
static void __init legacy_pic_uint_noop(unsigned int unused) { };
static void __init legacy_pic_int_noop(int unused) { };
static struct irq_chip dummy_pic_chip = {
.name = "dummy pic",
.mask = legacy_pic_uint_noop,
.unmask = legacy_pic_uint_noop,
.disable = legacy_pic_uint_noop,
.mask_ack = legacy_pic_uint_noop,
};
static int legacy_pic_irq_pending_noop(unsigned int irq)
{
return 0;
}
struct legacy_pic null_legacy_pic = {
.nr_legacy_irqs = 0,
.chip = &dummy_pic_chip,
.mask_all = legacy_pic_noop,
.restore_mask = legacy_pic_noop,
.init = legacy_pic_int_noop,
.irq_pending = legacy_pic_irq_pending_noop,
.make_irq = legacy_pic_uint_noop,
};
struct legacy_pic default_legacy_pic = {
.nr_legacy_irqs = NR_IRQS_LEGACY,
.chip = &i8259A_chip,
.mask_all = mask_8259A,
.restore_mask = unmask_8259A,
.init = init_8259A,
.irq_pending = i8259A_irq_pending,
.make_irq = make_8259A_irq,
};
struct legacy_pic *legacy_pic = &default_legacy_pic;