/*
 * Copyright (C) 2012-2015 - ARM Ltd
 * Author: Marc Zyngier <marc.zyngier@arm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/compiler.h>
#include <linux/irqchip/arm-gic-v3.h>
#include <linux/kvm_host.h>

#include <asm/kvm_emulate.h>
#include <asm/kvm_hyp.h>

#define vtr_to_max_lr_idx(v)		((v) & 0xf)
#define vtr_to_nr_pre_bits(v)		((((u32)(v) >> 26) & 7) + 1)

static u64 __hyp_text __gic_v3_get_lr(unsigned int lr)
{
	switch (lr & 0xf) {
	case 0:
		return read_gicreg(ICH_LR0_EL2);
	case 1:
		return read_gicreg(ICH_LR1_EL2);
	case 2:
		return read_gicreg(ICH_LR2_EL2);
	case 3:
		return read_gicreg(ICH_LR3_EL2);
	case 4:
		return read_gicreg(ICH_LR4_EL2);
	case 5:
		return read_gicreg(ICH_LR5_EL2);
	case 6:
		return read_gicreg(ICH_LR6_EL2);
	case 7:
		return read_gicreg(ICH_LR7_EL2);
	case 8:
		return read_gicreg(ICH_LR8_EL2);
	case 9:
		return read_gicreg(ICH_LR9_EL2);
	case 10:
		return read_gicreg(ICH_LR10_EL2);
	case 11:
		return read_gicreg(ICH_LR11_EL2);
	case 12:
		return read_gicreg(ICH_LR12_EL2);
	case 13:
		return read_gicreg(ICH_LR13_EL2);
	case 14:
		return read_gicreg(ICH_LR14_EL2);
	case 15:
		return read_gicreg(ICH_LR15_EL2);
	}

	unreachable();
}

static void __hyp_text __gic_v3_set_lr(u64 val, int lr)
{
	switch (lr & 0xf) {
	case 0:
		write_gicreg(val, ICH_LR0_EL2);
		break;
	case 1:
		write_gicreg(val, ICH_LR1_EL2);
		break;
	case 2:
		write_gicreg(val, ICH_LR2_EL2);
		break;
	case 3:
		write_gicreg(val, ICH_LR3_EL2);
		break;
	case 4:
		write_gicreg(val, ICH_LR4_EL2);
		break;
	case 5:
		write_gicreg(val, ICH_LR5_EL2);
		break;
	case 6:
		write_gicreg(val, ICH_LR6_EL2);
		break;
	case 7:
		write_gicreg(val, ICH_LR7_EL2);
		break;
	case 8:
		write_gicreg(val, ICH_LR8_EL2);
		break;
	case 9:
		write_gicreg(val, ICH_LR9_EL2);
		break;
	case 10:
		write_gicreg(val, ICH_LR10_EL2);
		break;
	case 11:
		write_gicreg(val, ICH_LR11_EL2);
		break;
	case 12:
		write_gicreg(val, ICH_LR12_EL2);
		break;
	case 13:
		write_gicreg(val, ICH_LR13_EL2);
		break;
	case 14:
		write_gicreg(val, ICH_LR14_EL2);
		break;
	case 15:
		write_gicreg(val, ICH_LR15_EL2);
		break;
	}
}

static void __hyp_text __vgic_v3_write_ap0rn(u32 val, int n)
{
	switch (n) {
	case 0:
		write_gicreg(val, ICH_AP0R0_EL2);
		break;
	case 1:
		write_gicreg(val, ICH_AP0R1_EL2);
		break;
	case 2:
		write_gicreg(val, ICH_AP0R2_EL2);
		break;
	case 3:
		write_gicreg(val, ICH_AP0R3_EL2);
		break;
	}
}

static void __hyp_text __vgic_v3_write_ap1rn(u32 val, int n)
{
	switch (n) {
	case 0:
		write_gicreg(val, ICH_AP1R0_EL2);
		break;
	case 1:
		write_gicreg(val, ICH_AP1R1_EL2);
		break;
	case 2:
		write_gicreg(val, ICH_AP1R2_EL2);
		break;
	case 3:
		write_gicreg(val, ICH_AP1R3_EL2);
		break;
	}
}

static u32 __hyp_text __vgic_v3_read_ap0rn(int n)
{
	u32 val;

	switch (n) {
	case 0:
		val = read_gicreg(ICH_AP0R0_EL2);
		break;
	case 1:
		val = read_gicreg(ICH_AP0R1_EL2);
		break;
	case 2:
		val = read_gicreg(ICH_AP0R2_EL2);
		break;
	case 3:
		val = read_gicreg(ICH_AP0R3_EL2);
		break;
	default:
		unreachable();
	}

	return val;
}

static u32 __hyp_text __vgic_v3_read_ap1rn(int n)
{
	u32 val;

	switch (n) {
	case 0:
		val = read_gicreg(ICH_AP1R0_EL2);
		break;
	case 1:
		val = read_gicreg(ICH_AP1R1_EL2);
		break;
	case 2:
		val = read_gicreg(ICH_AP1R2_EL2);
		break;
	case 3:
		val = read_gicreg(ICH_AP1R3_EL2);
		break;
	default:
		unreachable();
	}

	return val;
}

void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
{
	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
	u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
	u64 val;

	/*
	 * Make sure stores to the GIC via the memory mapped interface
	 * are now visible to the system register interface.
	 */
	if (!cpu_if->vgic_sre) {
		dsb(st);
		cpu_if->vgic_vmcr = read_gicreg(ICH_VMCR_EL2);
	}

	if (used_lrs) {
		int i;
		u32 nr_pre_bits;

		cpu_if->vgic_elrsr = read_gicreg(ICH_ELSR_EL2);

		write_gicreg(0, ICH_HCR_EL2);
		val = read_gicreg(ICH_VTR_EL2);
		nr_pre_bits = vtr_to_nr_pre_bits(val);

		for (i = 0; i < used_lrs; i++) {
			if (cpu_if->vgic_elrsr & (1 << i))
				cpu_if->vgic_lr[i] &= ~ICH_LR_STATE;
			else
				cpu_if->vgic_lr[i] = __gic_v3_get_lr(i);

			__gic_v3_set_lr(0, i);
		}

		switch (nr_pre_bits) {
		case 7:
			cpu_if->vgic_ap0r[3] = __vgic_v3_read_ap0rn(3);
			cpu_if->vgic_ap0r[2] = __vgic_v3_read_ap0rn(2);
		case 6:
			cpu_if->vgic_ap0r[1] = __vgic_v3_read_ap0rn(1);
		default:
			cpu_if->vgic_ap0r[0] = __vgic_v3_read_ap0rn(0);
		}

		switch (nr_pre_bits) {
		case 7:
			cpu_if->vgic_ap1r[3] = __vgic_v3_read_ap1rn(3);
			cpu_if->vgic_ap1r[2] = __vgic_v3_read_ap1rn(2);
		case 6:
			cpu_if->vgic_ap1r[1] = __vgic_v3_read_ap1rn(1);
		default:
			cpu_if->vgic_ap1r[0] = __vgic_v3_read_ap1rn(0);
		}
	} else {
		cpu_if->vgic_elrsr = 0xffff;
		cpu_if->vgic_ap0r[0] = 0;
		cpu_if->vgic_ap0r[1] = 0;
		cpu_if->vgic_ap0r[2] = 0;
		cpu_if->vgic_ap0r[3] = 0;
		cpu_if->vgic_ap1r[0] = 0;
		cpu_if->vgic_ap1r[1] = 0;
		cpu_if->vgic_ap1r[2] = 0;
		cpu_if->vgic_ap1r[3] = 0;
	}

	val = read_gicreg(ICC_SRE_EL2);
	write_gicreg(val | ICC_SRE_EL2_ENABLE, ICC_SRE_EL2);

	if (!cpu_if->vgic_sre) {
		/* Make sure ENABLE is set at EL2 before setting SRE at EL1 */
		isb();
		write_gicreg(1, ICC_SRE_EL1);
	}
}

void __hyp_text __vgic_v3_restore_state(struct kvm_vcpu *vcpu)
{
	struct vgic_v3_cpu_if *cpu_if = &vcpu->arch.vgic_cpu.vgic_v3;
	u64 used_lrs = vcpu->arch.vgic_cpu.used_lrs;
	u64 val;
	u32 nr_pre_bits;
	int i;

	/*
	 * VFIQEn is RES1 if ICC_SRE_EL1.SRE is 1. This causes a
	 * Group0 interrupt (as generated in GICv2 mode) to be
	 * delivered as a FIQ to the guest, with potentially fatal
	 * consequences. So we must make sure that ICC_SRE_EL1 has
	 * been actually programmed with the value we want before
	 * starting to mess with the rest of the GIC, and VMCR_EL2 in
	 * particular.
	 */
	if (!cpu_if->vgic_sre) {
		write_gicreg(0, ICC_SRE_EL1);
		isb();
		write_gicreg(cpu_if->vgic_vmcr, ICH_VMCR_EL2);
	}

	val = read_gicreg(ICH_VTR_EL2);
	nr_pre_bits = vtr_to_nr_pre_bits(val);

	if (used_lrs) {
		write_gicreg(cpu_if->vgic_hcr, ICH_HCR_EL2);

		switch (nr_pre_bits) {
		case 7:
			__vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[3], 3);
			__vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[2], 2);
		case 6:
			__vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[1], 1);
		default:
			__vgic_v3_write_ap0rn(cpu_if->vgic_ap0r[0], 0);
		}

		switch (nr_pre_bits) {
		case 7:
			__vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[3], 3);
			__vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[2], 2);
		case 6:
			__vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[1], 1);
		default:
			__vgic_v3_write_ap1rn(cpu_if->vgic_ap1r[0], 0);
		}

		for (i = 0; i < used_lrs; i++)
			__gic_v3_set_lr(cpu_if->vgic_lr[i], i);
	}

	/*
	 * Ensures that the above will have reached the
	 * (re)distributors. This ensure the guest will read the
	 * correct values from the memory-mapped interface.
	 */
	if (!cpu_if->vgic_sre) {
		isb();
		dsb(sy);
	}

	/*
	 * Prevent the guest from touching the GIC system registers if
	 * SRE isn't enabled for GICv3 emulation.
	 */
	write_gicreg(read_gicreg(ICC_SRE_EL2) & ~ICC_SRE_EL2_ENABLE,
		     ICC_SRE_EL2);
}

void __hyp_text __vgic_v3_init_lrs(void)
{
	int max_lr_idx = vtr_to_max_lr_idx(read_gicreg(ICH_VTR_EL2));
	int i;

	for (i = 0; i <= max_lr_idx; i++)
		__gic_v3_set_lr(0, i);
}

u64 __hyp_text __vgic_v3_get_ich_vtr_el2(void)
{
	return read_gicreg(ICH_VTR_EL2);
}

u64 __hyp_text __vgic_v3_read_vmcr(void)
{
	return read_gicreg(ICH_VMCR_EL2);
}

void __hyp_text __vgic_v3_write_vmcr(u32 vmcr)
{
	write_gicreg(vmcr, ICH_VMCR_EL2);
}

#ifdef CONFIG_ARM64

static int __hyp_text __vgic_v3_bpr_min(void)
{
	/* See Pseudocode for VPriorityGroup */
	return 8 - vtr_to_nr_pre_bits(read_gicreg(ICH_VTR_EL2));
}

static unsigned int __hyp_text __vgic_v3_get_bpr0(u32 vmcr)
{
	return (vmcr & ICH_VMCR_BPR0_MASK) >> ICH_VMCR_BPR0_SHIFT;
}

static unsigned int __hyp_text __vgic_v3_get_bpr1(u32 vmcr)
{
	unsigned int bpr;

	if (vmcr & ICH_VMCR_CBPR_MASK) {
		bpr = __vgic_v3_get_bpr0(vmcr);
		if (bpr < 7)
			bpr++;
	} else {
		bpr = (vmcr & ICH_VMCR_BPR1_MASK) >> ICH_VMCR_BPR1_SHIFT;
	}

	return bpr;
}

static void __hyp_text __vgic_v3_read_bpr1(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
{
	vcpu_set_reg(vcpu, rt, __vgic_v3_get_bpr1(vmcr));
}

static void __hyp_text __vgic_v3_write_bpr1(struct kvm_vcpu *vcpu, u32 vmcr, int rt)
{
	u64 val = vcpu_get_reg(vcpu, rt);
	u8 bpr_min = __vgic_v3_bpr_min();

	if (vmcr & ICH_VMCR_CBPR_MASK)
		return;

	/* Enforce BPR limiting */
	if (val < bpr_min)
		val = bpr_min;

	val <<= ICH_VMCR_BPR1_SHIFT;
	val &= ICH_VMCR_BPR1_MASK;
	vmcr &= ~ICH_VMCR_BPR1_MASK;
	vmcr |= val;

	__vgic_v3_write_vmcr(vmcr);
}

int __hyp_text __vgic_v3_perform_cpuif_access(struct kvm_vcpu *vcpu)
{
	int rt;
	u32 esr;
	u32 vmcr;
	void (*fn)(struct kvm_vcpu *, u32, int);
	bool is_read;
	u32 sysreg;

	esr = kvm_vcpu_get_hsr(vcpu);
	if (vcpu_mode_is_32bit(vcpu)) {
		if (!kvm_condition_valid(vcpu))
			return 1;

		sysreg = esr_cp15_to_sysreg(esr);
	} else {
		sysreg = esr_sys64_to_sysreg(esr);
	}

	is_read = (esr & ESR_ELx_SYS64_ISS_DIR_MASK) == ESR_ELx_SYS64_ISS_DIR_READ;

	switch (sysreg) {
	case SYS_ICC_BPR1_EL1:
		if (is_read)
			fn = __vgic_v3_read_bpr1;
		else
			fn = __vgic_v3_write_bpr1;
		break;
	default:
		return 0;
	}

	vmcr = __vgic_v3_read_vmcr();
	rt = kvm_vcpu_sys_get_rt(vcpu);
	fn(vcpu, vmcr, rt);

	return 1;
}

#endif