/*
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2025 Sophgo Inc.
 *
 * Authors:
 *   Haijiao Liu <haijiao.liu@sophgo.com>
 */

#include <libfdt.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_string.h>
#include <sbi/sbi_console.h>
#include <sbi/sbi_ecall_interface.h>
#include <sbi/sbi_clk.h>
#include <sbi/sbi_cppc.h>
#include <sbi_utils/cppc/fdt_cppc.h>

#define CPPC_REGISTER_WIDTH	64
#define CPPC_REGISTER_NOT_IMPLEMENTED	0

static char clock_names[64];
static uint64_t clk_granularity;

static int sg2044_cppc_read(unsigned long reg, u64 *val)
{
	int rc = SBI_SUCCESS;

	switch (reg) {
	case SBI_CPPC_DESIRED_PERF:
		*val = sbi_clk_get_rate(clock_names) / clk_granularity;
		break;
	default:
		rc = SBI_ERR_NOT_SUPPORTED;
	}

	return rc;
}

static int sg2044_cppc_write(unsigned long reg, u64 val)
{
	int rc = SBI_SUCCESS;

	switch (reg) {
	case SBI_CPPC_DESIRED_PERF:
		rc = sbi_clk_set_rate(clock_names, val * clk_granularity);
		break;
	default:
		rc = SBI_ERR_NOT_SUPPORTED;
	}

	return rc;
}

static int sg2044_cppc_probe(unsigned long reg)
{
	int rc;

	switch (reg) {
	case SBI_CPPC_DESIRED_PERF:
		rc = CPPC_REGISTER_WIDTH;
		break;
	default:
		rc = CPPC_REGISTER_NOT_IMPLEMENTED;
	}

	return rc;
}

static struct sbi_cppc_device sbi_sg2044_cppc = {
	.name		= "sg2044-cppc",
	.cppc_read	= sg2044_cppc_read,
	.cppc_write	= sg2044_cppc_write,
	.cppc_probe	= sg2044_cppc_probe,
};

static int sg2044_cppc_cold_init(const void *fdt, int nodeoff,
				 const struct fdt_match *match)
{
	const struct sbi_clk_device *clk;
	const fdt32_t *val;
	const char *name;
	int len;

	clk = sbi_clk_get_device(fdt);
	if (!clk)
		return SBI_ENODEV;

	val = fdt_getprop(fdt, nodeoff, "step", &len);
	if (!val)
		return SBI_EINVAL;

	clk_granularity = fdt32_to_cpu(val[0]);
	clk_granularity = (clk_granularity << 32) | fdt32_to_cpu(val[1]);

	name = fdt_getprop(fdt, nodeoff, "clock-names", &len);
	if (!name)
		return SBI_EINVAL;

	sbi_strncpy(clock_names, name, MIN(sizeof(clock_names), len));

	sbi_cppc_set_device(&sbi_sg2044_cppc);

	return 0;
}

static const struct fdt_match sg2044_cppc_match[] = {
	{ .compatible = "sophgo,sg2044-cppc" },
	{},
};

struct fdt_driver fdt_cppc_sg2044 = {
	.match_table = sg2044_cppc_match,
	.init = sg2044_cppc_cold_init,
};