// SPDX-License-Identifier: GPL-2.0-only
/*
 * drivers/soc/tegra/flowctrl.c
 *
 * Functions and macros to control the flowcontroller
 *
 * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
 */

#include <linux/cpumask.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>

#include <soc/tegra/common.h>
#include <soc/tegra/flowctrl.h>
#include <soc/tegra/fuse.h>

static u8 flowctrl_offset_halt_cpu[] = {
        FLOW_CTRL_HALT_CPU0_EVENTS,
        FLOW_CTRL_HALT_CPU1_EVENTS,
        FLOW_CTRL_HALT_CPU1_EVENTS + 8,
        FLOW_CTRL_HALT_CPU1_EVENTS + 16,
};

static u8 flowctrl_offset_cpu_csr[] = {
        FLOW_CTRL_CPU0_CSR,
        FLOW_CTRL_CPU1_CSR,
        FLOW_CTRL_CPU1_CSR + 8,
        FLOW_CTRL_CPU1_CSR + 16,
};

static void __iomem *tegra_flowctrl_base;

static void flowctrl_update(u8 offset, u32 value)
{
        if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base),
                      "Tegra flowctrl not initialised!\n"))
                return;

        writel(value, tegra_flowctrl_base + offset);

        /* ensure the update has reached the flow controller */
        wmb();
        readl_relaxed(tegra_flowctrl_base + offset);
}

u32 flowctrl_read_cpu_csr(unsigned int cpuid)
{
        u8 offset = flowctrl_offset_cpu_csr[cpuid];

        if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base),
                      "Tegra flowctrl not initialised!\n"))
                return 0;

        return readl(tegra_flowctrl_base + offset);
}

void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
{
        return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value);
}

void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value)
{
        return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value);
}

void flowctrl_cpu_suspend_enter(unsigned int cpuid)
{
        unsigned int reg;
        int i;

        reg = flowctrl_read_cpu_csr(cpuid);
        switch (tegra_get_chip_id()) {
        case TEGRA20:
                /* clear wfe bitmap */
                reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
                /* clear wfi bitmap */
                reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
                /* pwr gating on wfe */
                reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid;
                break;
        case TEGRA30:
        case TEGRA114:
        case TEGRA124:
                /* clear wfe bitmap */
                reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
                /* clear wfi bitmap */
                reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;

                if (tegra_get_chip_id() == TEGRA30) {
                        /*
                         * The wfi doesn't work well on Tegra30 because
                         * CPU hangs under some odd circumstances after
                         * power-gating (like memory running off PLLP),
                         * hence use wfe that is working perfectly fine.
                         * Note that Tegra30 TRM doc clearly stands that
                         * wfi should be used for the "Cluster Switching",
                         * while wfe for the power-gating, just like it
                         * is done on Tegra20.
                         */
                        reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid;
                } else {
                        /* pwr gating on wfi */
                        reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid;
                }
                break;
        }
        reg |= FLOW_CTRL_CSR_INTR_FLAG;                 /* clear intr flag */
        reg |= FLOW_CTRL_CSR_EVENT_FLAG;                /* clear event flag */
        reg |= FLOW_CTRL_CSR_ENABLE;                    /* pwr gating */
        flowctrl_write_cpu_csr(cpuid, reg);

        for (i = 0; i < num_possible_cpus(); i++) {
                if (i == cpuid)
                        continue;
                reg = flowctrl_read_cpu_csr(i);
                reg |= FLOW_CTRL_CSR_EVENT_FLAG;
                reg |= FLOW_CTRL_CSR_INTR_FLAG;
                flowctrl_write_cpu_csr(i, reg);
        }
}

void flowctrl_cpu_suspend_exit(unsigned int cpuid)
{
        unsigned int reg;

        /* Disable powergating via flow controller for CPU0 */
        reg = flowctrl_read_cpu_csr(cpuid);
        switch (tegra_get_chip_id()) {
        case TEGRA20:
                /* clear wfe bitmap */
                reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
                /* clear wfi bitmap */
                reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
                break;
        case TEGRA30:
        case TEGRA114:
        case TEGRA124:
                /* clear wfe bitmap */
                reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
                /* clear wfi bitmap */
                reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;
                break;
        }
        reg &= ~FLOW_CTRL_CSR_ENABLE;                   /* clear enable */
        reg |= FLOW_CTRL_CSR_INTR_FLAG;                 /* clear intr */
        reg |= FLOW_CTRL_CSR_EVENT_FLAG;                /* clear event */
        flowctrl_write_cpu_csr(cpuid, reg);
}

static int tegra_flowctrl_probe(struct platform_device *pdev)
{
        void __iomem *base = tegra_flowctrl_base;
        struct resource *res;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        tegra_flowctrl_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(tegra_flowctrl_base))
                return PTR_ERR(tegra_flowctrl_base);

        iounmap(base);

        return 0;
}

static const struct of_device_id tegra_flowctrl_match[] = {
        { .compatible = "nvidia,tegra210-flowctrl" },
        { .compatible = "nvidia,tegra124-flowctrl" },
        { .compatible = "nvidia,tegra114-flowctrl" },
        { .compatible = "nvidia,tegra30-flowctrl" },
        { .compatible = "nvidia,tegra20-flowctrl" },
        { }
};

static struct platform_driver tegra_flowctrl_driver = {
        .driver = {
                .name = "tegra-flowctrl",
                .suppress_bind_attrs = true,
                .of_match_table = tegra_flowctrl_match,
        },
        .probe = tegra_flowctrl_probe,
};
builtin_platform_driver(tegra_flowctrl_driver);

static int __init tegra_flowctrl_init(void)
{
        struct resource res;
        struct device_node *np;

        if (!soc_is_tegra())
                return 0;

        np = of_find_matching_node(NULL, tegra_flowctrl_match);
        if (np) {
                if (of_address_to_resource(np, 0, &res) < 0) {
                        pr_err("failed to get flowctrl register\n");
                        return -ENXIO;
                }
                of_node_put(np);
        } else if (IS_ENABLED(CONFIG_ARM)) {
                /*
                 * Hardcoded fallback for 32-bit Tegra
                 * devices if device tree node is missing.
                 */
                res.start = 0x60007000;
                res.end = 0x60007fff;
                res.flags = IORESOURCE_MEM;
        } else {
                /*
                 * At this point we're running on a Tegra,
                 * that doesn't support the flow controller
                 * (eg. Tegra186), so just return.
                 */
                return 0;
        }

        tegra_flowctrl_base = ioremap(res.start, resource_size(&res));
        if (!tegra_flowctrl_base)
                return -ENXIO;

        return 0;
}
early_initcall(tegra_flowctrl_init);