/*
 * Copyright (c) 2020 ITE Corporation. All Rights Reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */

#include <zephyr/arch/riscv/csr.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/init.h>
#include <soc.h>
#include "soc_espi.h"
#include <zephyr/dt-bindings/interrupt-controller/ite-intc.h>

#ifdef CONFIG_SOC_IT8XXX2_PLL_FLASH_48M
#define __intc_ram_code __attribute__((section(".__ram_code")))

struct pll_config_t {
	uint8_t pll_freq;
	uint8_t div_fnd;
	uint8_t div_uart;
	uint8_t div_smb;
	uint8_t div_sspi;
	uint8_t div_ec;
	uint8_t div_jtag;
	uint8_t div_pwm;
	uint8_t div_usbpd;
};

static const struct pll_config_t pll_configuration[] = {
	/*
	 * PLL frequency setting = 4 (48MHz)
	 * FND   div = 0 (PLL / 1 = 48 mhz)
	 * UART  div = 1 (PLL / 2 = 24 mhz)
	 * SMB   div = 1 (PLL / 2 = 24 mhz)
	 * SSPI  div = 1 (PLL / 2 = 24 mhz)
	 * EC    div = 6 (FND / 6 =  8 mhz)
	 * JTAG  div = 1 (PLL / 2 = 24 mhz)
	 * PWM   div = 0 (PLL / 1 = 48 mhz)
	 * USBPD div = 5 (PLL / 6 =  8 mhz)
	 */
	{.pll_freq  = 4,
	 .div_fnd   = 0,
	 .div_uart  = 1,
	 .div_smb   = 1,
	 .div_sspi  = 1,
	 .div_ec    = 6,
	 .div_jtag  = 1,
	 .div_pwm   = 0,
	 .div_usbpd = 5}
};

uint32_t chip_get_pll_freq(void)
{
	uint32_t pllfreq;

	switch (IT8XXX2_ECPM_PLLFREQR & 0x0F) {
	case 0:
		pllfreq = MHZ(8);
		break;
	case 1:
		pllfreq = MHZ(16);
		break;
	case 2:
		pllfreq = MHZ(24);
		break;
	case 3:
		pllfreq = MHZ(32);
		break;
	case 4:
		pllfreq = MHZ(48);
		break;
	case 5:
		pllfreq = MHZ(64);
		break;
	case 6:
		pllfreq = MHZ(72);
		break;
	case 7:
		pllfreq = MHZ(96);
		break;
	default:
		return -ERANGE;
	}

	return pllfreq;
}

void __intc_ram_code chip_pll_ctrl(enum chip_pll_mode mode)
{
	volatile uint8_t _pll_ctrl __unused;

	IT8XXX2_ECPM_PLLCTRL = mode;
	/*
	 * for deep doze / sleep mode
	 * This load operation will ensure PLL setting is taken into
	 * control register before wait for interrupt instruction.
	 */
	_pll_ctrl = IT8XXX2_ECPM_PLLCTRL;
}

void __intc_ram_code chip_run_pll_sequence(const struct pll_config_t *pll)
{
	/* Enable HW timer to wakeup chip from the sleep mode */
	timer_5ms_one_shot();
	/*
	 * Configure PLL clock dividers.
	 * Writing data to these registers doesn't change the
	 * PLL frequency immediately until the status is changed
	 * into wakeup from the sleep mode.
	 * The following code is intended to make the system
	 * enter sleep mode, and wait HW timer to wakeup chip to
	 * complete PLL update.
	 */
	IT8XXX2_ECPM_PLLFREQR = pll->pll_freq;
	/* Pre-set FND clock frequency = PLL / 3 */
	IT8XXX2_ECPM_SCDCR0 = (2 << 4);
	/* JTAG and EC */
	IT8XXX2_ECPM_SCDCR3 = (pll->div_jtag << 4) | pll->div_ec;
	/* Chip sleep after wait for interrupt (wfi) instruction */
	chip_pll_ctrl(CHIP_PLL_SLEEP);
	/* Chip sleep and wait timer wake it up */
	__asm__ volatile  ("wfi");
	/* New FND clock frequency */
	IT8XXX2_ECPM_SCDCR0 = pll->div_fnd << 4;
	/* Chip doze after wfi instruction */
	chip_pll_ctrl(CHIP_PLL_DOZE);
	/* UART */
	IT8XXX2_ECPM_SCDCR1 = pll->div_uart;
	/* SSPI and SMB */
	IT8XXX2_ECPM_SCDCR2 = (pll->div_sspi << 4) | pll->div_smb;
	/* USBPD and PWM */
	IT8XXX2_ECPM_SCDCR4 = (pll->div_usbpd << 4) | pll->div_pwm;
}

static void chip_configure_pll(const struct pll_config_t *pll)
{
	/* Re-configure PLL clock or not. */
	if (((IT8XXX2_ECPM_PLLFREQR & 0xf) != pll->pll_freq) ||
		((IT8XXX2_ECPM_SCDCR0 & 0xf0) != (pll->div_fnd << 4)) ||
		((IT8XXX2_ECPM_SCDCR3 & 0xf) != pll->div_ec)) {
#ifdef CONFIG_ESPI
		/*
		 * We have to disable eSPI pad before changing
		 * PLL sequence or sequence will fail if CS# pin is low.
		 */
		espi_it8xxx2_enable_pad_ctrl(ESPI_IT8XXX2_SOC_DEV, false);
#endif
		/* Run change PLL sequence */
		chip_run_pll_sequence(pll);
#ifdef CONFIG_ESPI
		/* Enable eSPI pad after changing PLL sequence */
		espi_it8xxx2_enable_pad_ctrl(ESPI_IT8XXX2_SOC_DEV, true);
#endif
	}
}

static int chip_change_pll(const struct device *dev)
{
	ARG_UNUSED(dev);

	if (IS_ENABLED(CONFIG_ITE_IT8XXX2_INTC)) {
		ite_intc_save_and_disable_interrupts();
	}
	/* configure PLL/CPU/flash clock */
	chip_configure_pll(&pll_configuration[0]);
	if (IS_ENABLED(CONFIG_ITE_IT8XXX2_INTC)) {
		ite_intc_restore_interrupts();
	}

	return 0;
}
SYS_INIT(chip_change_pll, PRE_KERNEL_1, CONFIG_IT8XXX2_PLL_SEQUENCE_PRIORITY);
BUILD_ASSERT(CONFIG_FLASH_INIT_PRIORITY < CONFIG_IT8XXX2_PLL_SEQUENCE_PRIORITY,
	"CONFIG_FLASH_INIT_PRIORITY must be less than CONFIG_IT8XXX2_PLL_SEQUENCE_PRIORITY");
#endif /* CONFIG_SOC_IT8XXX2_PLL_FLASH_48M */

/* The routine must be called with interrupts locked */
void riscv_idle(enum chip_pll_mode mode, unsigned int key)
{
	/*
	 * The routine is called with interrupts locked (in kernel/idle()).
	 * But on kernel/context test_kernel_cpu_idle test, the routine will be
	 * called without interrupts locked. Hence we disable M-mode external
	 * interrupt here to protect the below content.
	 */
	csr_clear(mie, MIP_MEIP);
	sys_trace_idle();
	/* Chip doze after wfi instruction */
	chip_pll_ctrl(mode);

	do {
		/* Wait for interrupt */
		__asm__ volatile ("wfi");
		/*
		 * Sometimes wfi instruction may fail due to CPU's MTIP@mip
		 * register is non-zero.
		 * If the ite_intc_no_irq() is true at this point,
		 * it means that EC waked-up by the above issue not an
		 * interrupt. Hence we loop running wfi instruction here until
		 * wfi success.
		 */
	} while (ite_intc_no_irq());

	/*
	 * Enable M-mode external interrupt
	 * An interrupt can not be fired yet until we enable global interrupt
	 */
	csr_set(mie, MIP_MEIP);
	/* Restore global interrupt lockout state */
	irq_unlock(key);
}

void arch_cpu_idle(void)
{
	riscv_idle(CHIP_PLL_DOZE, MSTATUS_IEN);
}

void arch_cpu_atomic_idle(unsigned int key)
{
	riscv_idle(CHIP_PLL_DOZE, key);
}

void soc_interrupt_init(void)
{
	ite_intc_init();
}

static int ite_it8xxx2_init(const struct device *arg)
{
	ARG_UNUSED(arg);

	/*
	 * bit7: wake up CPU if it is in low power mode and
	 * an interrupt is pending.
	 */
	IT83XX_GCTRL_WMCR |= BIT(7);

#if DT_NODE_HAS_STATUS(DT_NODELABEL(uart1), okay)
	/* UART1 board init */
	/* bit2: clocks to UART1 modules are not gated. */
	IT8XXX2_ECPM_CGCTRL3R &= ~BIT(2);
	IT8XXX2_ECPM_AUTOCG &= ~BIT(6);

	/* bit3: UART1 belongs to the EC side. */
	IT83XX_GCTRL_RSTDMMC |= BIT(3);
	/* reset UART before config it */
	IT83XX_GCTRL_RSTC4 = BIT(1);

	/* switch UART1 on without hardware flow control */
	IT8XXX2_GPIO_GRC1 |= BIT(0);

#endif /* DT_NODE_HAS_STATUS(DT_NODELABEL(uart1), okay) */

#if DT_NODE_HAS_STATUS(DT_NODELABEL(uart2), okay)
	/* UART2 board init */
	/* setting voltage 3.3v */
	IT8XXX2_GPIO_GRC21 &= ~(BIT(0) | BIT(1));
	/* bit2: clocks to UART2 modules are not gated. */
	IT8XXX2_ECPM_CGCTRL3R &= ~BIT(2);
	IT8XXX2_ECPM_AUTOCG &= ~BIT(5);

	/* bit3: UART2 belongs to the EC side. */
	IT83XX_GCTRL_RSTDMMC |= BIT(2);
	/* reset UART before config it */
	IT83XX_GCTRL_RSTC4 = BIT(2);

	/* switch UART2 on without hardware flow control */
	IT8XXX2_GPIO_GRC1 |= BIT(2);

#endif /* DT_NODE_HAS_STATUS(DT_NODELABEL(uart2), okay) */
	return 0;
}
SYS_INIT(ite_it8xxx2_init, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);