/*
 * Copyright (c) 1984-2008, 2011-2015 Wind River Systems, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file
 * @brief LoApicIntr.c - Intel Pentium[234] Local APIC/xAPIC driver
 *
 * This module is a driver for the local APIC/xAPIC (Advanced Programmable
 * Interrupt Controller) in P6 (PentiumPro, II, III) family processors
 * and P7 (Pentium4) family processors.  The local APIC/xAPIC is included
 * in selected P6 (PentiumPro, II, III) and P7 (Pentium4) family processors.
 * Beginning with the P6 family processors, the presence or absence of an
 * on-chip local APIC can be detected using the CPUID instruction.  When the
 * CPUID instruction is executed, bit 9 of the feature flags returned in the
 * EDX register indicates the presence (set) or absence (clear) of an on-chip
 * local APIC.
 *
 * The local APIC performs two main functions for the processor:
 *  - It processes local external interrupts that the processor receives at its
 *    interrupt pins and local internal interrupts that software generates.
 *  - It communicates with an external IO APIC
 *    chip.  The external IO APIC receives external interrupt events from
 *    peripheral and direct them to the local APIC.  The IO APIC is
 *    part of Intel's system chip set.
 * The local APIC controls the dispatching of interrupts (to its associated
 * processor) that it receives either locally or from the IO APIC.  It provides
 * facilities for queuing, nesting and masking of interrupts.  It handles the
 * interrupt delivery protocol with its local processor and accesses to APIC
 * registers.
 * A timer on the local APIC allows local generation of interrupts, and
 * local interrupt pins permit local reception of processor-specific interrupts.
 * The local APIC can be disabled and used in conjunction with a standard 8259A
 * style interrupt controller.  Disabling the local APIC can be done in hardware
 * for the Pentium processors or in software for the P6 and P7 (Pentium4) family
 * processors.
 *
 * The local APIC in the Pentium4 processors (called the xAPIC) is an extension
 * of the local APIC found in the P6 family processors.  The primary difference
 * between the APIC architecture and xAPIC architecture is that with Pentium4
 * processors, the local xAPICs and IO xAPIC communicate with one another
 * through the processors system bus; whereas, with the P6 family processors,
 * communication between the local APICs and the IO APIC is handled through a
 * dedicated 3-wire APIC bus.  Also, some of the architectural features of the
 * local APIC have been extended and/or modified in the local xAPIC.
 *
 * This driver contains three routines for use.  They are:
 * _loapic_init() initializes the Local APIC for the interrupt mode chosen.
 * _loapic_enable()/disable() enables / disables the Local APIC.
 *
 * Local APIC is used in the Virtual Wire Mode: delivery mode ExtINT.
 *
 * Virtual Wire Mode is one of three interrupt modes defined by the MP
 * specification.  In this mode, interrupts are generated by the 8259A
 * equivalent PICs (if present) and delivered to the Boot Strap Processor by
 * the local APIC that is programmed to act as a "virtual Wire"; that
 * is, the local APIC is logically indistinguishable from a hardware
 * connection.  This is a uniprocessor compatibility mode.
 *
 * The local and IO APICs support interrupts in the range of 32 to 255.
 * Interrupt priority is implied by its vector, according to the following
 * relationship:  "priority = vector / 16".
 * Here the quotient is rounded down to the nearest integer value to determine
 * the priority, with 1 being the lowest and 15 is the highest.  Because vectors
 * 0 through 31 are reserved for exclusive use by the processor, the priority of
 * user defined interrupts range from 2 to 15.  A value of 15 in the Interrupt
 * Class field of the Task Priority Register (TPR) will mask off all interrupts,
 * which require interrupt service.
 * The P6 family processor's local APIC includes an in-service entry and a
 * holding entry for each priority level.  To avoid losing interrupts, software
 * should allocate no more than 2 interrupt vectors per priority.  The Pentium4
 * processor expands this support of all acceptance of two interrupts per vector
 * rather than per priority level.
 *
 * INCLUDE FILES: loapic.h
 */

#include <nanokernel.h>
#include <arch/cpu.h>
#include <stdint.h>

#include "board.h"
#include <toolchain.h>
#include <sections.h>
#include <drivers/loapic.h> /* public API declarations */
#include <init.h>

/* IA32_APIC_BASE MSR Bits */

#define LOAPIC_BASE_MASK 0xfffff000     /* LO APIC Base Addr mask */
#define LOAPIC_GLOBAL_ENABLE 0x00000800 /* LO APIC Global Enable */

/* Local APIC ID Register Bits */

#define LOAPIC_ID_MASK 0x0f000000 /* LO APIC ID mask */

/* Local APIC Version Register Bits */

#define LOAPIC_VERSION_MASK 0x000000ff /* LO APIC Version mask */
#define LOAPIC_MAXLVT_MASK 0x00ff0000  /* LO APIC Max LVT mask */
#define LOAPIC_PENTIUM4 0x00000014     /* LO APIC in Pentium4 */
#define LOAPIC_LVT_PENTIUM4 5	  /* LO APIC LVT - Pentium4 */
#define LOAPIC_LVT_P6 4		       /* LO APIC LVT - P6 */
#define LOAPIC_LVT_P5 3		       /* LO APIC LVT - P5 */

/* Local APIC Vector Table Bits */

#define LOAPIC_VECTOR 0x000000ff /* vectorNo */
#define LOAPIC_MODE 0x00000700   /* delivery mode */
#define LOAPIC_FIXED 0x00000000  /* delivery mode: FIXED */
#define LOAPIC_SMI 0x00000200    /* delivery mode: SMI */
#define LOAPIC_NMI 0x00000400    /* delivery mode: NMI */
#define LOAPIC_EXT 0x00000700    /* delivery mode: ExtINT */
#define LOAPIC_IDLE 0x00000000   /* delivery status: Idle */
#define LOAPIC_PEND 0x00001000   /* delivery status: Pend */
#define LOAPIC_HIGH 0x00000000   /* polarity: High */
#define LOAPIC_LOW 0x00002000    /* polarity: Low */
#define LOAPIC_REMOTE 0x00004000 /* remote IRR */
#define LOAPIC_EDGE 0x00000000   /* trigger mode: Edge */
#define LOAPIC_LEVEL 0x00008000  /* trigger mode: Level */

/* Local APIC Spurious-Interrupt Register Bits */

#define LOAPIC_ENABLE 0x100	/* APIC Enabled */
#define LOAPIC_FOCUS_DISABLE 0x200 /* Focus Processor Checking */

/* Local Vector's lock-unlock macro used in loApicIntLock/Unlock */

#define LOCKED_TIMER 0x01
#define LOCKED_PMC 0x02
#define LOCKED_LINT0 0x04
#define LOCKED_LINT1 0x08
#define LOCKED_ERROR 0x10
#define LOCKED_THERMAL 0x20

/* Interrupt Command Register: delivery mode and status */

#define MODE_FIXED 0x0     /* delivery mode: Fixed */
#define MODE_LOWEST 0x1    /* delivery mode: Lowest */
#define MODE_SMI 0x2       /* delivery mode: SMI */
#define MODE_NMI 0x4       /* delivery mode: NMI */
#define MODE_INIT 0x5      /* delivery mode: INIT */
#define MODE_STARTUP 0x6   /* delivery mode: StartUp */
#define STATUS_PEND 0x1000 /* delivery status: Pend */

/* MP Configuration Table Entries */

#define MP_ENTRY_CPU 0	 /* Entry Type: CPU */
#define MP_ENTRY_BUS 1	 /* Entry Type: BUS */
#define MP_ENTRY_IOAPIC 2      /* Entry Type: IO APIC */
#define MP_ENTRY_IOINTERRUPT 3 /* Entry Type: IO INT */
#define MP_ENTRY_LOINTERRUPT 4 /* Entry Type: LO INT */

/* Extended MP Configuration Table Entries */

#define EXT_MP_ENTRY_SASM 128  /* Entry Type: System Address Space Map */
#define EXT_MP_ENTRY_BHD 129   /* Entry Type: Bus Hierarchy Descriptor */
#define EXT_MP_ENTRY_CBASM 130 /* Entry Type: Comp Address Space Modifier */

/* MP Configuration Table CPU Flags */

#define MP_CPU_FLAGS_BP 0x02

/* IMCR related bits */

#define IMCR_ADRS 0x22       /* IMCR addr reg */
#define IMCR_DATA 0x23       /* IMCR data reg */
#define IMCR_REG_SEL 0x70    /* IMCR reg select */
#define IMCR_IOAPIC_ON 0x01  /* IMCR IOAPIC route enable */
#define IMCR_IOAPIC_OFF 0x00 /* IMCR IOAPIC route disable */

#if CONFIG_LOAPIC_SPURIOUS_VECTOR_ID == -1
#define LOAPIC_SPURIOUS_VECTOR_ID (CONFIG_IDT_NUM_VECTORS - 1)
#else
#define LOAPIC_SPURIOUS_VECTOR_ID CONFIG_LOAPIC_SPURIOUS_VECTOR_ID
#endif

/**
 *
 * @brief Initialize the Local APIC or xAPIC
 *
 * This routine initializes Local APIC or xAPIC.
 *
 * @return N/A
 *
 */

int _loapic_init(struct device *unused)
{
	ARG_UNUSED(unused);
	int32_t loApicMaxLvt; /* local APIC Max LVT */

	/* enable the Local APIC */

	_loapic_enable();

	loApicMaxLvt = (*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_VER) &
			LOAPIC_MAXLVT_MASK) >> 16;

	/* reset the DFR, TPR, TIMER_CONFIG, and TIMER_ICR */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_DFR) =
		(int)0xffffffff;
	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TPR) = (int)0x0;
	*(volatile int *) (CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER_CONFIG) =
		(int)0x0;
	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER_ICR) = (int)0x0;

	/* program Local Vector Table for the Virtual Wire Mode */

	/* set LINT0: extInt, high-polarity, edge-trigger, not-masked */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_LINT0) =
		(*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_LINT0) &
		 ~(LOAPIC_MODE | LOAPIC_LOW | LOAPIC_LEVEL | LOAPIC_LVT_MASKED)) |
		(LOAPIC_EXT | LOAPIC_HIGH | LOAPIC_EDGE);

	/* set LINT1: NMI, high-polarity, edge-trigger, not-masked */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_LINT1) =
		(*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_LINT1) &
		 ~(LOAPIC_MODE | LOAPIC_LOW | LOAPIC_LEVEL | LOAPIC_LVT_MASKED)) |
		(LOAPIC_NMI | LOAPIC_HIGH | LOAPIC_EDGE);

	/* lock the Local APIC interrupts */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER) =
		LOAPIC_LVT_MASKED;
	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_ERROR) =
		LOAPIC_LVT_MASKED;

	if (loApicMaxLvt >= LOAPIC_LVT_P6)
		*(volatile int *) (CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_PMC) =
			LOAPIC_LVT_MASKED;

	if (loApicMaxLvt >= LOAPIC_LVT_PENTIUM4)
		*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_THERMAL) =
			LOAPIC_LVT_MASKED;

#if CONFIG_LOAPIC_SPURIOUS_VECTOR
	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_SVR) =
		(*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_SVR) & 0xFFFFFF00)
		| (LOAPIC_SPURIOUS_VECTOR_ID & 0xFF);
#endif

	/* discard a pending interrupt if any */
	_loapic_eoi();
	return 0;
}

/**
 *
 * @brief Enable the Local xAPIC
 *
 * This routine enables the Local xAPIC.
 *
 * @return N/A
 */

void _loapic_enable(void)
{
	int32_t oldLevel = irq_lock(); /* LOCK INTERRUPTS */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_SVR) |= LOAPIC_ENABLE;

	irq_unlock(oldLevel); /* UNLOCK INTERRUPTS */
}

/**
 *
 * @brief Disable the Local xAPIC
 *
 * This routine disables the Local xAPIC.
 *
 * @return N/A
 */

void _loapic_disable(void)
{
	int32_t oldLevel = irq_lock(); /* LOCK INTERRUPTS */

	*(volatile int *)(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_SVR) &=
		~LOAPIC_ENABLE;

	irq_unlock(oldLevel); /* UNLOCK INTERRUPTS */
}

/**
 *
 * @brief Set the vector field in the specified RTE
 *
 * This routine is utilized by the interrupt controller's _SysIntVecAlloc()
 * routine (which exists to support the irq_connect_dynamic() API).  Once
 * a vector has been allocated, this routine is invoked to update the LVT
 * entry associated with <irq> with the vector.
 *
 * @return N/A
 */

void _loapic_int_vec_set(unsigned int irq, /* IRQ number of the interrupt */
				  unsigned int vector /* vector to copy into the LVT */
				  )
{
	volatile int *pLvt; /* pointer to local vector table */
	int32_t oldLevel;   /* previous interrupt lock level */

	/*
	 * The following mappings are used:
	 *
	 *   IRQ0 -> LOAPIC_TIMER
	 *   IRQ1 -> LOAPIC_THERMAL
	 *   IRQ2 -> LOAPIC_PMC
	 *   IRQ3 -> LOAPIC_LINT0
	 *   IRQ4 -> LOAPIC_LINT1
	 *   IRQ5 -> LOAPIC_ERROR
	 *
	 * It's assumed that LVTs are spaced by 0x10 bytes
	 */

	pLvt = (volatile int *)
			(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER + (irq * 0x10));

	/* update the 'vector' bits in the LVT */

	oldLevel = irq_lock();
	*pLvt = (*pLvt & ~LOAPIC_VECTOR) | vector;
	irq_unlock(oldLevel);
}

/**
 *
 * @brief Enable an individual LOAPIC interrupt (IRQ)
 *
 * @param irq the IRQ number of the interrupt
 *
 * This routine clears the interrupt mask bit in the LVT for the specified IRQ
 *
 * @return N/A
 */

void _loapic_irq_enable(unsigned int irq)
{
	volatile int *pLvt; /* pointer to local vector table */
	int32_t oldLevel;   /* previous interrupt lock level */

	/*
	 * See the comments in _LoApicLvtVecSet() regarding IRQ to LVT mappings
	 * and ths assumption concerning LVT spacing.
	 */

	pLvt = (volatile int *)
		(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER + (irq * 0x10));

	/* clear the mask bit in the LVT */

	oldLevel = irq_lock();
	*pLvt = *pLvt & ~LOAPIC_LVT_MASKED;
	irq_unlock(oldLevel);
}

/**
 *
 * @brief Disable an individual LOAPIC interrupt (IRQ)
 *
 * @param irq the IRQ number of the interrupt
 *
 * This routine clears the interrupt mask bit in the LVT for the specified IRQ
 *
 * @return N/A
 */

void _loapic_irq_disable(unsigned int irq)
{
	volatile int *pLvt; /* pointer to local vector table */
	int32_t oldLevel;   /* previous interrupt lock level */

	/*
	 * See the comments in _LoApicLvtVecSet() regarding IRQ to LVT mappings
	 * and ths assumption concerning LVT spacing.
	 */

	pLvt = (volatile int *)
		(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_TIMER + (irq * 0x10));

	/* set the mask bit in the LVT */

	oldLevel = irq_lock();
	*pLvt = *pLvt | LOAPIC_LVT_MASKED;
	irq_unlock(oldLevel);
}


/**
 * @brief Find the currently executing interrupt vector, if any
 *
 * This routine finds the vector of the interrupt that is being processed.
 * The ISR (In-Service Register) register contain the vectors of the interrupts
 * in service. And the higher vector is the indentification of the interrupt
 * being currently processed.
 *
 * ISR registers' offsets:
 * --------------------
 * | Offset | bits    |
 * --------------------
 * | 0100H  |   0:31  |
 * | 0110H  |  32:63  |
 * | 0120H  |  64:95  |
 * | 0130H  |  96:127 |
 * | 0140H  | 128:159 |
 * | 0150H  | 160:191 |
 * | 0160H  | 192:223 |
 * | 0170H  | 224:255 |
 * --------------------
 *
 * @return The vector of the interrupt that is currently being processed.
 */
int _loapic_isr_vector_get(void)
{
	/* pointer to ISR vector table */
	volatile int *pReg;
	int block = 0;

	while (block < 8) {
		pReg = (volatile int *)
		(CONFIG_LOAPIC_BASE_ADDRESS + LOAPIC_ISR + (block * 0x10));
		if (*pReg) {
			return (block * 32) + (find_lsb_set(*pReg) - 1);
		}
		block++;
	}

	return 0;
}

SYS_INIT(_loapic_init, PRIMARY, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

#if CONFIG_LOAPIC_SPURIOUS_VECTOR
extern void _loapic_spurious_handler(void);

NANO_CPU_INT_REGISTER(_loapic_spurious_handler, NANO_SOFT_IRQ,
		      LOAPIC_SPURIOUS_VECTOR_ID >> 4,
		      LOAPIC_SPURIOUS_VECTOR_ID, 0);
#endif