/* SPDX-License-Identifier: GPL-2.0-only */

#include <acpi/acpi.h>
#include <acpi/acpigen.h>
#include <console/console.h>
#include <cpu/cpu.h>
#include <cpu/intel/speedstep.h>
#include <cpu/intel/turbo.h>
#include <cpu/x86/msr.h>
#include <device/device.h>
#include <stdint.h>

#include "model_206ax.h"
#include "chip.h"

#define MWAIT_RES(state, sub_state)                         \
	{                                                   \
		.addrl = (((state) << 4) | (sub_state)),    \
		.space_id = ACPI_ADDRESS_SPACE_FIXED,       \
		.bit_width = ACPI_FFIXEDHW_VENDOR_INTEL,    \
		.bit_offset = ACPI_FFIXEDHW_CLASS_MWAIT,    \
		.access_size = ACPI_FFIXEDHW_FLAG_HW_COORD, \
	}

/*
 * List of supported C-states in this processor
 *
 * Latencies are typical worst-case package exit time in uS
 * taken from the SandyBridge BIOS specification.
 */
static acpi_cstate_t cstate_map[NUM_C_STATES] = {
	[C_STATE_C0] = { },
	[C_STATE_C1] = {
		.latency = 1,
		.power = 1000,
		.resource = MWAIT_RES(0, 0),
	},
	[C_STATE_C1E] = {
		.latency = 1,
		.power = 1000,
		.resource = MWAIT_RES(0, 1),
	},
	[C_STATE_C3] = {
		.latency = 63,
		.power = 500,
		.resource = MWAIT_RES(1, 0),
	},
	[C_STATE_C6] = {
		.latency = 87,
		.power = 350,
		.resource = MWAIT_RES(2, 0),
	},
	[C_STATE_C7] = {
		.latency = 90,
		.power = 200,
		.resource = MWAIT_RES(3, 0),
	},
	[C_STATE_C7S] = {
		.latency = 90,
		.power = 200,
		.resource = MWAIT_RES(3, 1),
	},
};

static const char *const c_state_names[] = {"C0", "C1", "C1E", "C3", "C6", "C7", "C7S"};

static int get_logical_cores_per_package(void)
{
	msr_t msr = rdmsr(MSR_CORE_THREAD_COUNT);
	return msr.lo & 0xffff;
}

static void print_supported_cstates(void)
{
	uint8_t state, substate;

	printk(BIOS_DEBUG, "Supported C-states: ");

	for (size_t i = 0; i < ARRAY_SIZE(cstate_map); i++) {
		state = (cstate_map[i].resource.addrl >> 4) + 1;
		substate = cstate_map[i].resource.addrl & 0xf;

		/* CPU C0 is always supported */
		if (i == 0 || cpu_get_c_substate_support(state) > substate)
			printk(BIOS_DEBUG, " %s", c_state_names[i]);
	}
	printk(BIOS_DEBUG, "\n");
}

/*
 * Returns the supported C-state or the next lower one that
 * is supported.
 */
static int get_supported_cstate(int cstate)
{
	uint8_t state, substate;
	size_t i;

	assert(cstate < NUM_C_STATES);

	for (i = cstate; i > 0; i--) {
		state = (cstate_map[i].resource.addrl >> 4) + 1;
		substate = cstate_map[i].resource.addrl & 0xf;
		if (cpu_get_c_substate_support(state) > substate)
			break;
	}

	if (cstate != i)
		printk(BIOS_INFO, "Requested C-state %s not supported, using %s instead\n",
		       c_state_names[cstate], c_state_names[i]);

	return i;
}

static void generate_C_state_entries(const struct device *dev)
{
	struct cpu_intel_model_206ax_config *conf = dev->chip_info;

	int acpi_cstates[3] = { conf->acpi_c1, conf->acpi_c2, conf->acpi_c3 };

	acpi_cstate_t acpi_cstate_map[ARRAY_SIZE(acpi_cstates)] = { 0 };
	/* Count number of active C-states */
	int count = 0;

	for (int i = 0; i < ARRAY_SIZE(acpi_cstates); i++) {
		/* Remove invalid states */
		if (acpi_cstates[i] >= ARRAY_SIZE(cstate_map)) {
			printk(BIOS_ERR, "Invalid C-state in devicetree: %d\n",
			       acpi_cstates[i]);
			acpi_cstates[i] = 0;
			continue;
		}
		/* Skip C0, it's always supported */
		if (acpi_cstates[i] == 0)
			continue;

		/* Find supported state. Might downgrade a state. */
		acpi_cstates[i] = get_supported_cstate(acpi_cstates[i]);

		/* Remove duplicate states */
		for (int j = i - 1; j >= 0; j--) {
			if (acpi_cstates[i] == acpi_cstates[j]) {
				acpi_cstates[i] = 0;
				break;
			}
		}
	}

	/* Convert C-state to ACPI C-states */
	for (int i = 0; i < ARRAY_SIZE(acpi_cstates); i++) {
		if (acpi_cstates[i] == 0)
			continue;
		acpi_cstate_map[count] = cstate_map[acpi_cstates[i]];
		acpi_cstate_map[count].ctype = i + 1;

		count++;
		printk(BIOS_DEBUG, "Advertising ACPI C State type C%d as CPU %s\n",
		       i + 1, c_state_names[acpi_cstates[i]]);
	}

	acpigen_write_CST_package(acpi_cstate_map, count);
}

static acpi_tstate_t tss_table_fine[] = {
	{ 100, 1000, 0, 0x00, 0 },
	{ 94, 940, 0, 0x1f, 0 },
	{ 88, 880, 0, 0x1e, 0 },
	{ 82, 820, 0, 0x1d, 0 },
	{ 75, 760, 0, 0x1c, 0 },
	{ 69, 700, 0, 0x1b, 0 },
	{ 63, 640, 0, 0x1a, 0 },
	{ 57, 580, 0, 0x19, 0 },
	{ 50, 520, 0, 0x18, 0 },
	{ 44, 460, 0, 0x17, 0 },
	{ 38, 400, 0, 0x16, 0 },
	{ 32, 340, 0, 0x15, 0 },
	{ 25, 280, 0, 0x14, 0 },
	{ 19, 220, 0, 0x13, 0 },
	{ 13, 160, 0, 0x12, 0 },
};

static acpi_tstate_t tss_table_coarse[] = {
	{ 100, 1000, 0, 0x00, 0 },
	{ 88, 875, 0, 0x1f, 0 },
	{ 75, 750, 0, 0x1e, 0 },
	{ 63, 625, 0, 0x1d, 0 },
	{ 50, 500, 0, 0x1c, 0 },
	{ 38, 375, 0, 0x1b, 0 },
	{ 25, 250, 0, 0x1a, 0 },
	{ 13, 125, 0, 0x19, 0 },
};

static void generate_T_state_entries(int core, int cores_per_package)
{
	/* Indicate SW_ALL coordination for T-states */
	acpigen_write_TSD_package(core, cores_per_package, SW_ALL);

	/* Indicate FFixedHW so OS will use MSR */
	acpigen_write_empty_PTC();

	/* Set a T-state limit that can be modified in NVS */
	acpigen_write_TPC("\\TLVL");

	/*
	 * CPUID.(EAX=6):EAX[5] indicates support
	 * for extended throttle levels.
	 */
	if (cpuid_eax(6) & (1 << 5))
		acpigen_write_TSS_package(
			ARRAY_SIZE(tss_table_fine), tss_table_fine);
	else
		acpigen_write_TSS_package(
			ARRAY_SIZE(tss_table_coarse), tss_table_coarse);
}

static int calculate_power(int tdp, int p1_ratio, int ratio)
{
	u32 m;
	u32 power;

	/*
	 * M = ((1.1 - ((p1_ratio - ratio) * 0.00625)) / 1.1) ^ 2
	 *
	 * Power = (ratio / p1_ratio) * m * tdp
	 */

	m = (110000 - ((p1_ratio - ratio) * 625)) / 11;
	m = (m * m) / 1000;

	power = ((ratio * 100000 / p1_ratio) / 100);
	power *= (m / 100) * (tdp / 1000);
	power /= 1000;

	return (int)power;
}

static void generate_P_state_entries(int core, int cores_per_package)
{
	int ratio_min, ratio_max, ratio_turbo, ratio_step;
	int coord_type, power_max, power_unit, num_entries;
	int ratio, power, clock, clock_max;
	msr_t msr;

	/* Determine P-state coordination type from MISC_PWR_MGMT[0] */
	msr = rdmsr(MSR_MISC_PWR_MGMT);
	if (msr.lo & MISC_PWR_MGMT_EIST_HW_DIS)
		coord_type = SW_ANY;
	else
		coord_type = HW_ALL;

	/* Get bus ratio limits and calculate clock speeds */
	msr = rdmsr(MSR_PLATFORM_INFO);
	ratio_min = (msr.hi >> (40-32)) & 0xff; /* Max Efficiency Ratio */

	/* Determine if this CPU has configurable TDP */
	if (cpu_config_tdp_levels()) {
		/* Set max ratio to nominal TDP ratio */
		msr = rdmsr(MSR_CONFIG_TDP_NOMINAL);
		ratio_max = msr.lo & 0xff;
	} else {
		/* Max Non-Turbo Ratio */
		ratio_max = (msr.lo >> 8) & 0xff;
	}
	clock_max = ratio_max * SANDYBRIDGE_BCLK;

	/* Calculate CPU TDP in mW */
	msr = rdmsr(MSR_PKG_POWER_SKU_UNIT);
	power_unit = 2 << ((msr.lo & 0xf) - 1);
	msr = rdmsr(MSR_PKG_POWER_SKU);
	power_max = ((msr.lo & 0x7fff) / power_unit) * 1000;

	/* Write _PCT indicating use of FFixedHW */
	acpigen_write_empty_PCT();

	/* Write _PPC with no limit on supported P-state */
	acpigen_write_PPC_NVS();

	/* Write PSD indicating configured coordination type */
	acpigen_write_PSD_package(core, cores_per_package, coord_type);

	/* Add P-state entries in _PSS table */
	acpigen_write_name("_PSS");

	/* Determine ratio points */
	ratio_step = PSS_RATIO_STEP;
	num_entries = (ratio_max - ratio_min) / ratio_step;
	while (num_entries > PSS_MAX_ENTRIES-1) {
		ratio_step <<= 1;
		num_entries >>= 1;
	}

	/* P[T] is Turbo state if enabled */
	if (get_turbo_state() == TURBO_ENABLED) {
		/* _PSS package count including Turbo */
		acpigen_write_package(num_entries + 2);

		msr = rdmsr(MSR_TURBO_RATIO_LIMIT);
		ratio_turbo = msr.lo & 0xff;

		/* Add entry for Turbo ratio */
		acpigen_write_PSS_package(
			clock_max + 1,		/*MHz*/
			power_max,		/*mW*/
			PSS_LATENCY_TRANSITION,	/*lat1*/
			PSS_LATENCY_BUSMASTER,	/*lat2*/
			ratio_turbo << 8,	/*control*/
			ratio_turbo << 8);	/*status*/
	} else {
		/* _PSS package count without Turbo */
		acpigen_write_package(num_entries + 1);
	}

	/* First regular entry is max non-turbo ratio */
	acpigen_write_PSS_package(
		clock_max,		/*MHz*/
		power_max,		/*mW*/
		PSS_LATENCY_TRANSITION,	/*lat1*/
		PSS_LATENCY_BUSMASTER,	/*lat2*/
		ratio_max << 8,		/*control*/
		ratio_max << 8);	/*status*/

	/* Generate the remaining entries */
	for (ratio = ratio_min + ((num_entries - 1) * ratio_step);
	     ratio >= ratio_min; ratio -= ratio_step) {
		/* Calculate power at this ratio */
		power = calculate_power(power_max, ratio_max, ratio);
		clock = ratio * SANDYBRIDGE_BCLK;

		acpigen_write_PSS_package(
			clock,			/*MHz*/
			power,			/*mW*/
			PSS_LATENCY_TRANSITION,	/*lat1*/
			PSS_LATENCY_BUSMASTER,	/*lat2*/
			ratio << 8,		/*control*/
			ratio << 8);		/*status*/
	}

	/* Fix package length */
	acpigen_pop_len();
}

static void generate_cpu_entry(const struct device *device, int cpu, int core, int cores_per_package)
{
	/* Generate Scope(\_SB) { Device(CPUx */
	acpigen_write_processor_device(cpu * cores_per_package + core);

	/* Generate P-state tables */
	generate_P_state_entries(cpu, cores_per_package);

	/* Generate C-state tables */
	generate_C_state_entries(device);

	/* Generate T-state tables */
	generate_T_state_entries(cpu, cores_per_package);

	acpigen_write_processor_device_end();
}

void generate_cpu_entries(const struct device *device)
{
	int totalcores = dev_count_cpu();
	int cores_per_package = get_logical_cores_per_package();
	int numcpus = totalcores / cores_per_package;

	printk(BIOS_DEBUG, "Found %d CPU(s) with %d core(s) each.\n",
	       numcpus, cores_per_package);

	print_supported_cstates();

	for (int cpu_id = 0; cpu_id < numcpus; cpu_id++)
		for (int core_id = 0; core_id < cores_per_package; core_id++)
			generate_cpu_entry(device, cpu_id, core_id, cores_per_package);

	/* PPKG is usually used for thermal management
	   of the first and only package. */
	acpigen_write_processor_package("PPKG", 0, cores_per_package);

	/* Add a method to notify processor nodes */
	acpigen_write_processor_cnot(cores_per_package);
}

struct chip_operations cpu_intel_model_206ax_ops = {
	CHIP_NAME("Intel SandyBridge/IvyBridge CPU")
};