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93 lines
2.4 KiB
93 lines
2.4 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/* |
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* include/asm-mips/i8259.h |
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* |
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* i8259A interrupt definitions. |
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* |
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* Copyright (C) 2003 Maciej W. Rozycki |
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* Copyright (C) 2003 Ralf Baechle <[email protected]> |
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*/ |
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#ifndef _ASM_I8259_H |
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#define _ASM_I8259_H |
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#include <linux/compiler.h> |
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#include <linux/spinlock.h> |
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#include <asm/io.h> |
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#include <irq.h> |
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/* i8259A PIC registers */ |
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#define PIC_MASTER_CMD 0x20 |
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#define PIC_MASTER_IMR 0x21 |
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#define PIC_MASTER_ISR PIC_MASTER_CMD |
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#define PIC_MASTER_POLL PIC_MASTER_ISR |
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#define PIC_MASTER_OCW3 PIC_MASTER_ISR |
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#define PIC_SLAVE_CMD 0xa0 |
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#define PIC_SLAVE_IMR 0xa1 |
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/* i8259A PIC related value */ |
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#define PIC_CASCADE_IR 2 |
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#define MASTER_ICW4_DEFAULT 0x01 |
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#define SLAVE_ICW4_DEFAULT 0x01 |
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#define PIC_ICW4_AEOI 2 |
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extern raw_spinlock_t i8259A_lock; |
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extern void make_8259A_irq(unsigned int irq); |
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extern void init_i8259_irqs(void); |
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extern struct irq_domain *__init_i8259_irqs(struct device_node *node); |
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/** |
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* i8159_set_poll() - Override the i8259 polling function |
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* @poll: pointer to platform-specific polling function |
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* |
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* Call this to override the generic i8259 polling function, which directly |
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* accesses i8259 registers, with a platform specific one which may be faster |
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* in cases where hardware provides a more optimal means of polling for an |
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* interrupt. |
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*/ |
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extern void i8259_set_poll(int (*poll)(void)); |
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/* |
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* Do the traditional i8259 interrupt polling thing. This is for the few |
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* cases where no better interrupt acknowledge method is available and we |
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* absolutely must touch the i8259. |
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*/ |
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static inline int i8259_irq(void) |
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{ |
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int irq; |
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raw_spin_lock(&i8259A_lock); |
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/* Perform an interrupt acknowledge cycle on controller 1. */ |
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outb(0x0C, PIC_MASTER_CMD); /* prepare for poll */ |
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irq = inb(PIC_MASTER_CMD) & 7; |
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if (irq == PIC_CASCADE_IR) { |
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/* |
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* Interrupt is cascaded so perform interrupt |
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* acknowledge on controller 2. |
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*/ |
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outb(0x0C, PIC_SLAVE_CMD); /* prepare for poll */ |
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irq = (inb(PIC_SLAVE_CMD) & 7) + 8; |
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} |
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if (unlikely(irq == 7)) { |
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/* |
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* This may be a spurious interrupt. |
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* |
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* Read the interrupt status register (ISR). If the most |
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* significant bit is not set then there is no valid |
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* interrupt. |
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*/ |
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outb(0x0B, PIC_MASTER_ISR); /* ISR register */ |
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if(~inb(PIC_MASTER_ISR) & 0x80) |
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irq = -1; |
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} |
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raw_spin_unlock(&i8259A_lock); |
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return likely(irq >= 0) ? irq + I8259A_IRQ_BASE : irq; |
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} |
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#endif /* _ASM_I8259_H */
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