/* Copyright (c) 2016 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 *
 * Set up the LM2 mIA core & interrupts
 */

#include "common.h"
#include "util.h"
#include "interrupts.h"
#include "registers.h"
#include "task_defs.h"
#include "irq_handler.h"
#include "console.h"

/* Console output macros */
#define CPUTS(outstr) cputs(CC_SYSTEM, outstr)
#define CPRINTF(format, args...) cprintf(CC_SYSTEM, format, ## args)
#define CPRINTS(format, args...) cprints(CC_SYSTEM, format, ## args)

/* The IDT  - initialized in init.S */
extern IDT_entry __idt[NUM_VECTORS];

/* To count the interrupt nesting depth. Usually it is not nested */
volatile uint32_t __in_isr;

void write_ioapic_reg(const uint32_t reg, const uint32_t val)
{
	REG32(IOAPIC_IDX) = (uint8_t)reg;
	REG32(IOAPIC_WDW) = val;
}

uint32_t read_ioapic_reg(const uint32_t reg)
{
	REG32(IOAPIC_IDX) = (uint8_t)reg;
	return REG32(IOAPIC_WDW);
}

void set_ioapic_redtbl_raw(const unsigned irq, const uint32_t val)
{
	const uint32_t redtbl_lo = IOAPIC_IOREDTBL + 2 * irq;
	const uint32_t redtbl_hi = redtbl_lo + 1;

	write_ioapic_reg(redtbl_lo, val);
	write_ioapic_reg(redtbl_hi, DEST_APIC_ID);
}

void unmask_interrupt(uint32_t irq)
{
	uint32_t val;
	const uint32_t redtbl_lo = IOAPIC_IOREDTBL + 2 * irq;

	val = read_ioapic_reg(redtbl_lo);
	val &= ~IOAPIC_REDTBL_MASK;
	set_ioapic_redtbl_raw(irq, val);
}

void mask_interrupt(uint32_t irq)
{
	uint32_t val;
	const uint32_t redtbl_lo = IOAPIC_IOREDTBL + 2 * irq;

	val = read_ioapic_reg(redtbl_lo);
	val |= IOAPIC_REDTBL_MASK;
	set_ioapic_redtbl_raw(irq, val);
}

/* Maps IRQs to vectors. To be programmed in IOAPIC redirection table */
static const irq_desc_t system_irqs[] = {
	LEVEL_INTR(ISH_I2C0_IRQ, ISH_I2C0_VEC),
	LEVEL_INTR(ISH_I2C1_IRQ, ISH_I2C1_VEC),
	LEVEL_INTR(ISH_I2C2_IRQ, ISH_I2C2_VEC),
	LEVEL_INTR(ISH_IPC_HOST2ISH_IRQ, ISH_IPC_VEC),
	LEVEL_INTR(ISH_HPET_TIMER0_IRQ, ISH_HPET_TIMER0_VEC),
	LEVEL_INTR(ISH_HPET_TIMER1_IRQ, ISH_HPET_TIMER1_VEC),
	LEVEL_INTR(ISH_DEBUG_UART_IRQ, ISH_DEBUG_UART_VEC),
};


void set_interrupt_gate(uint8_t num, isr_handler_t func, uint8_t flags)
{
	uint16_t code_segment;
	uint32_t base = (uint32_t) func;

	__idt[num].ISR_low = (uint16_t) (base & USHRT_MAX);
	__idt[num].ISR_high = (uint16_t) ((base >> 16UL) & USHRT_MAX);

	/* When the flat model is used the CS will never change. */
	__asm volatile ("mov %%cs, %0":"=r" (code_segment));
	__idt[num].segment_selector = code_segment;
	__idt[num].zero = 0;
	__idt[num].flags = flags;
}

void unhandled_vector(void)
{
	uint32_t vec = 0xff, i;
	uint32_t ioapic_icr_last = LAPIC_ISR_REG; /* In service register */

	/* Scan ISRs */
	for (i = 7; i >= 0; i--, ioapic_icr_last -= 0x10) {

		asm("movl (%1), %0\n" : "=&r" (vec) : "r" (ioapic_icr_last));
		if (vec) {
			vec = (32 * __fls(vec)) + i;
			break;
		}
	}

	CPRINTF("Ignoring vector 0x%0x!\n", vec);
	asm("" : : "a" (vec));
}

/* This needs to be moved to link_defs.h */
extern const struct irq_data __irq_data[], __irq_data_end[];

void init_interrupts(void)
{
	unsigned entry;
	const struct irq_data *p = __irq_data;
	unsigned num_system_irqs = ARRAY_SIZE(system_irqs);
	unsigned max_entries = (read_ioapic_reg(IOAPIC_VERSION) >> 16) & 0xff;

	/* Setup gates for IRQs declared by drivers using DECLARE_IRQ */
	for (; p < __irq_data_end; p++)
		set_interrupt_gate(IRQ_TO_VEC(p->irq), p->routine, IDT_FLAGS);

	/* Mask all interrupts by default in IOAPIC */
	for (entry = 0; entry < max_entries; entry++)
		set_ioapic_redtbl_raw(entry, IOAPIC_REDTBL_MASK);

	/* Enable pre-defined interrupts */
	for (entry = 0; entry < num_system_irqs; entry++)
		set_ioapic_redtbl_raw(system_irqs[entry].irq,
				      system_irqs[entry].vector |
				      IOAPIC_REDTBL_DELMOD_FIXED |
				      IOAPIC_REDTBL_DESTMOD_PHYS |
				      IOAPIC_REDTBL_MASK |
				      system_irqs[entry].polarity |
				      system_irqs[entry].trigger);

	set_interrupt_gate(ISH_TS_VECTOR, __switchto, IDT_FLAGS);

	/* Note: At reset, ID field is already set to 0 in APIC ID register */

	/* Enable the APIC, mapping the spurious interrupt at the same time. */
	APIC_SPURIOUS_INT = LAPIC_SPURIOUS_INT_VECTOR | APIC_ENABLE_BIT;

	/* Set timer error vector. */
	APIC_LVT_ERROR = LAPIC_LVT_ERROR_VECTOR;
}