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[pic8259] Return previous state when enabling or disabling IRQs 

Return the previous interrupt enabled state from enable_irq() and
disable_irq(), to allow callers to more easily restore this state.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/1165/merge
Michael Brown 2025-03-14 14:09:26 +00:00
parent d1133956d1
commit 8840de4096
1 changed files with 44 additions and 3 deletions
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47
src/arch/x86/include/pic8259.h
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@ -47,9 +47,6 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/* Macros to enable/disable IRQs */
#define IMR_REG(x) ( (x) < IRQ_PIC_CUTOFF ? PIC1_IMR : PIC2_IMR )
#define IMR_BIT(x) ( 1 << ( (x) % IRQ_PIC_CUTOFF ) )
#define irq_enabled(x) ( ( inb ( IMR_REG(x) ) & IMR_BIT(x) ) == 0 )
#define enable_irq(x) outb ( inb( IMR_REG(x) ) & ~IMR_BIT(x), IMR_REG(x) )
#define disable_irq(x) outb ( inb( IMR_REG(x) ) | IMR_BIT(x), IMR_REG(x) )
/* Macros for acknowledging IRQs */
#define ICR_REG( irq ) ( (irq) < IRQ_PIC_CUTOFF ? PIC1_ICR : PIC2_ICR )
@ -63,6 +60,50 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define IRQ_MAX 15
#define IRQ_NONE -1U
/**
* Check if interrupt is enabled
*
* @v irq Interrupt number
* @ret enabled Interrupt is currently enabled
*/
static inline __attribute__ (( always_inline )) int
irq_enabled ( unsigned int irq ) {
int imr = inb ( IMR_REG ( irq ) );
int mask = IMR_BIT ( irq );
return ( ( imr & mask ) == 0 );
}
/**
* Enable interrupt
*
* @v irq Interrupt number
* @ret enabled Interrupt was previously enabled
*/
static inline __attribute__ (( always_inline )) int
enable_irq ( unsigned int irq ) {
int imr = inb ( IMR_REG ( irq ) );
int mask = IMR_BIT ( irq );
outb ( ( imr & ~mask ), IMR_REG ( irq ) );
return ( ( imr & mask ) == 0 );
}
/**
* Disable interrupt
*
* @v irq Interrupt number
* @ret enabled Interrupt was previously enabled
*/
static inline __attribute__ (( always_inline )) int
disable_irq ( unsigned int irq ) {
int imr = inb ( IMR_REG ( irq ) );
int mask = IMR_BIT ( irq );
outb ( ( imr | mask ), IMR_REG ( irq ) );
return ( ( imr & mask ) == 0 );
}
/* Function prototypes
*/
void send_eoi ( unsigned int irq );