/*
 * Copyright (c) 2023 Ian Marco Moffett and the Osmora Team.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Hyra nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef _AMD64_LAPICVAR_H_
#define _AMD64_LAPICVAR_H_

#include <sys/cdefs.h>

/* LAPIC register offsets */
#define LAPIC_ID            0x0020U     /* ID Register */
#define LAPIC_VERSION       0x0030U     /* Version Register */
#define LAPIC_TPR           0x0080U     /* Task Priority Register */
#define LAPIC_APR           0x0090U     /* Arbitration Priority Register */
#define LAPIC_PPR           0x00A0U     /* Processor Priority Register */
#define LAPIC_EOI           0x00B0U     /* End Of Interrupt Register */
#define LAPIC_RRD           0x00C0U     /* Remote Read Register */
#define LAPIC_LDR           0x00D0U     /* Logical Destination Register */
#define LAPIC_DFR           0x00E0U     /* Destination Format Register */
#define LAPIC_SVR           0x00F0U     /* Spurious Vector Register */
#define LAPIC_ISR           0x0100U     /* In service register (max=0x0220) */
#define LAPIC_TMR           0x0180U     /* Trigger Mode Register (max=0x0220) */
#define LAPIC_IRR           0x0200U     /* Interrupt Request Register (max=0x0270) */
#define LAPIC_ERR           0x0280U     /* Error Status Register */
#define LAPIC_LVT_TMR       0x0320U     /* LVT Timer Register */
#define LAPIC_DCR           0x03E0U     /* Divide Configuration Register (for timer) */
#define LAPIC_INIT_CNT      0x0380U     /* Initial Count Register (for timer) */
#define LAPIC_CUR_CNT       0x0390U     /* Current Count Register (for timer) */

#define IA32_APIC_BASE_MSR  0x1B

/*
 * The x2APIC register space is accessed via
 * RDMSR/WRMSR instructions. The below defines
 * the base MSR address for the register space.
 */
#define x2APIC_MSR_BASE 0x00000800

/*
 * To hardware enable, OR the value
 * of the IA32_APIC_BASE MSR with
 * LAPIC_HW_ENABLE and rewrite it.
 *
 * To software enable, OR the value
 * of the SVR with LAPIC_SW_ENABLE
 * and rewrite it.
 *
 * LAPIC_SW_ENABLE has the low 8 bits set
 * as some hardware requires the spurious
 * vector to be hardwired to 1s so we'll
 * go with that to be safe.
 */
#define LAPIC_HW_ENABLE     __BIT(11)
#define LAPIC_SW_ENABLE     (__BIT(8) | 0xFF)
#define x2APIC_ENABLE_SHIFT 10

/*
 * The initial logical APIC ID to be set
 *
 * XXX: This value does *not* apply to processors
 *      that support x2APIC mode. In x2APIC mode
 *      the LDR register is readonly to system software.
 */
#define LAPIC_STARTUP_LID   0x1

/* LVT bits */
#define LAPIC_LVT_MASK            __BIT(16)

/*
 * Local APIC Interrupt stack [IST VALUE].
 *
 * This value should be non-zero and reserved
 * for only 1 interrupt vector to prevent clobbering
 * of the interrupt stacks.
 *
 * XXX TODO: The value is correctly 0, however, this needs
 *           to be updated to a non-zero value as soon as
 *           possible.
 */
#define LAPIC_TMR_INTSTACK  0

#endif  /* !_AMD64_LAPICVAR_H_ */