arch/x86/include/asm/irq.h

/*
 * Copyright (C) 2015, Bin Meng <bmeng.cn@gmail.com>
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#ifndef _ARCH_IRQ_H_
#define _ARCH_IRQ_H_

#include <dt-bindings/interrupt-router/intel-irq.h>

/**
 * Intel interrupt router configuration mechanism
 *
 * There are two known ways of Intel interrupt router configuration mechanism
 * so far. On most cases, the IRQ routing configuraiton is controlled by PCI
 * configuraiton registers on the legacy bridge, normally PCI BDF(0, 31, 0).
 * On some newer platforms like BayTrail and Braswell, the IRQ routing is now
 * in the IBASE register block where IBASE is memory-mapped.
 */
enum pirq_config {
	PIRQ_VIA_PCI,
	PIRQ_VIA_IBASE
};

/**
 * Intel interrupt router control block
 *
 * Its members' value will be filled in based on device tree's input.
 *
 * @config:	PIRQ_VIA_PCI or PIRQ_VIA_IBASE
 * @link_base:	link value base number
 * @irq_mask:	IRQ mask reprenting the 16 IRQs in 8259, bit N is 1 means
 *		IRQ N is available to be routed
 * @lb_bdf:	irq router's PCI bus/device/function number encoding
 * @ibase:	IBASE register block base address
 */
struct irq_router {
	int config;
	u32 link_base;
	u16 irq_mask;
	u32 bdf;
	u32 ibase;
};

struct pirq_routing {
	int bdf;
	int pin;
	int pirq;
};

/* PIRQ link number and value conversion */
#define LINK_V2N(link, base)	(link - base)
#define LINK_N2V(link, base)	(link + base)

#define PIRQ_BITMAP		0xdef8

/**
 * cpu_irq_init() - Initialize CPU IRQ routing
 *
 * This initializes some platform-specific registers related to IRQ routing,
 * like configuring internal PCI devices to use which PCI interrupt pin,
 * and which PCI interrupt pin is mapped to which PIRQ line. Note on some
 * platforms, such IRQ routing might be hard-coded thus cannot configure.
 */
void cpu_irq_init(void);

/**
 * pirq_init() - Initialize platform PIRQ routing
 *
 * This initializes the PIRQ routing on the platform and configures all PCI
 * devices' interrupt line register to a working IRQ number on the 8259 PIC.
 *
 * @return 0 if OK, -ve on error
 */
int pirq_init(void);

#endif /* _ARCH_IRQ_H_ */