powerpc/sysdev/i8259.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * i8259 interrupt controller driver.
8 #include <linux/interrupt.h>
26  * Acknowledge the IRQ using either the PCI host bridge's interrupt
29  * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
36 	/* Either int-ack or poll for the IRQ */  in i8259_irq()
43 		/* Perform an interrupt acknowledge cycle on controller 1. */  in i8259_irq()
48 			 * Interrupt is cascaded so perform interrupt  in i8259_irq()
49 			 * acknowledge on controller 2.  in i8259_irq()
58 		 * This may be a spurious interrupt.  in i8259_irq()
60 		 * Read the interrupt status register (ISR). If the most  in i8259_irq()
62 		 * interrupt.  in i8259_irq()
81 	if (d->irq > 7) {  in i8259_mask_and_ack_irq()
82 		cached_A1 |= 1 << (d->irq-8);  in i8259_mask_and_ack_irq()
85 		outb(0x20, 0xA0);	/* Non-specific EOI */  in i8259_mask_and_ack_irq()
86 		outb(0x20, 0x20);	/* Non-specific EOI to cascade */  in i8259_mask_and_ack_irq()
88 		cached_21 |= 1 << d->irq;  in i8259_mask_and_ack_irq()
91 		outb(0x20, 0x20);	/* Non-specific EOI */  in i8259_mask_and_ack_irq()
106 	pr_debug("i8259_mask_irq(%d)\n", d->irq);  in i8259_mask_irq()
109 	if (d->irq < 8)  in i8259_mask_irq()
110 		cached_21 |= 1 << d->irq;  in i8259_mask_irq()
112 		cached_A1 |= 1 << (d->irq-8);  in i8259_mask_irq()
113 	i8259_set_irq_mask(d->irq);  in i8259_mask_irq()
121 	pr_debug("i8259_unmask_irq(%d)\n", d->irq);  in i8259_unmask_irq()
124 	if (d->irq < 8)  in i8259_unmask_irq()
125 		cached_21 &= ~(1 << d->irq);  in i8259_unmask_irq()
127 		cached_A1 &= ~(1 << (d->irq-8));  in i8259_unmask_irq()
128 	i8259_set_irq_mask(d->irq);  in i8259_unmask_irq()
217  * i8259_init - Initialize the legacy controller
218  * @node: device node of the legacy PIC (can be NULL, but then, it will match
220  * @intack_addr: PCI interrupt acknowledge (real) address which will return
227 	/* initialize the controller */  in i8259_init()
234 	/* init master interrupt controller */  in i8259_init()
240 	/* init slave interrupt controller */  in i8259_init()
256 	/* Set interrupt masks */  in i8259_init()
262 	/* create a legacy host */  in i8259_init()
282 	printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");  in i8259_init()