i8259 Chip Support

i8259 Chip Support More...

Files
file	i8259.h
	Data structure and functions used to control i8259 chip.

Type definition for RTEMS managed interrupts
typedef unsigned short	rtems_i8259_masks
volatile rtems_i8259_masks	i8259s_cache

Function Prototypes
void	BSP_i8259s_init (void)
int	BSP_irq_disable_at_i8259s (const rtems_irq_number irqLine)
	function to disable a particular irq at 8259 level.
int	BSP_irq_enable_at_i8259s (const rtems_irq_number irqLine)
	function to enable a particular irq at 8259 level.
int	BSP_irq_ack_at_i8259s (const rtems_irq_number irqLine)
	function to acknowledge a particular irq at 8259 level.
int	BSP_irq_enabled_at_i8259s (const rtems_irq_number irqLine)
	function to check if a particular irq is enabled at 8259 level.
int	BSP_i8259s_int_process (void)
void	BSP_rtems_irq_mng_init (unsigned cpuId)

8259 edge/level control definitions at VIA
#define	ISA8259_M_ELCR   0x4d0
#define	ISA8259_S_ELCR   0x4d1
#define	ELCRS_INT15_LVL   0x80
#define	ELCRS_INT14_LVL   0x40
#define	ELCRS_INT13_LVL   0x20
#define	ELCRS_INT12_LVL   0x10
#define	ELCRS_INT11_LVL   0x08
#define	ELCRS_INT10_LVL   0x04
#define	ELCRS_INT9_LVL   0x02
#define	ELCRS_INT8_LVL   0x01
#define	ELCRM_INT7_LVL   0x80
#define	ELCRM_INT6_LVL   0x40
#define	ELCRM_INT5_LVL   0x20
#define	ELCRM_INT4_LVL   0x10
#define	ELCRM_INT3_LVL   0x8
#define	ELCRM_INT2_LVL   0x4
#define	ELCRM_INT1_LVL   0x2
#define	ELCRM_INT0_LVL   0x1

PIC's command and mask registers
#define	PIC_MASTER_COMMAND_IO_PORT   0x20
	Master PIC command register *‍/.
#define	PIC_SLAVE_COMMAND_IO_PORT   0xa0
	Slave PIC command register *‍/.
#define	PIC_MASTER_IMR_IO_PORT   0x21
	Master PIC Interrupt Mask Register *‍/.
#define	PIC_SLAVE_IMR_IO_PORT   0xa1
	Slave PIC Interrupt Mask Register *‍/.

Command for specific EOI (End Of Interrupt): Interrupt acknowledge
#define	PIC_EOSI   0x60
	End of Specific Interrupt (EOSI) *‍/.
#define	SLAVE_PIC_EOSI   0x62
	End of Specific Interrupt (EOSI) for cascade *‍/.
#define	PIC_EOI   0x20
	Generic End of Interrupt (EOI) *‍/.

Detailed Description

i8259 Chip Support

Function Documentation

BSP_irq_ack_at_i8259s()

int BSP_irq_ack_at_i8259s

(

const rtems_irq_number

irqLine

)

function to acknowledge a particular irq at 8259 level.

After calling this function, if a device asserts an enabled interrupt line it will be propagated further to the processor. Mainly useful for people writing raw handlers as this is automagically done for RTEMS managed handlers.

BSP_irq_disable_at_i8259s()

int BSP_irq_disable_at_i8259s

(

const rtems_irq_number

irqLine

)

function to disable a particular irq at 8259 level.

After calling this function, even if the device asserts the interrupt line it will not be propagated further to the processor.

Return values

1	the interrupt was enabled originally
0	the interrupt was disabled originally
<0	error

BSP_irq_enable_at_i8259s()

int BSP_irq_enable_at_i8259s

(

const rtems_irq_number

irqLine

)

function to enable a particular irq at 8259 level.

After calling this function, if the device asserts the interrupt line it will be propagated further to the processor.