// SPDX-License-Identifier: GPL-2.0
/*
 * rmobile power management support
 *
 * Copyright (C) 2012  Renesas Solutions Corp.
 * Copyright (C) 2012  Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 * Copyright (C) 2014  Glider bvba
 *
 * based on pm-sh7372.c
 *  Copyright (C) 2011 Magnus Damm
 */
#include <linux/clk/renesas.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/pm.h>
#include <linux/pm_clock.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>

/* SYSC */
#define SPDCR           0x08    /* SYS Power Down Control Register */
#define SWUCR           0x14    /* SYS Wakeup Control Register */
#define PSTR            0x80    /* Power Status Register */

#define PSTR_RETRIES    100
#define PSTR_DELAY_US   10

struct rmobile_pm_domain {
        struct generic_pm_domain genpd;
        struct dev_power_governor *gov;
        int (*suspend)(void);
        void __iomem *base;
        unsigned int bit_shift;
};

static inline
struct rmobile_pm_domain *to_rmobile_pd(struct generic_pm_domain *d)
{
        return container_of(d, struct rmobile_pm_domain, genpd);
}

static int rmobile_pd_power_down(struct generic_pm_domain *genpd)
{
        struct rmobile_pm_domain *rmobile_pd = to_rmobile_pd(genpd);
        unsigned int mask = BIT(rmobile_pd->bit_shift);
        u32 val;

        if (rmobile_pd->suspend) {
                int ret = rmobile_pd->suspend();

                if (ret)
                        return ret;
        }

        if (readl(rmobile_pd->base + PSTR) & mask) {
                writel(mask, rmobile_pd->base + SPDCR);

                readl_poll_timeout_atomic(rmobile_pd->base + SPDCR, val,
                                          !(val & mask), 0, PSTR_RETRIES);
        }

        pr_debug("%s: Power off, 0x%08x -> PSTR = 0x%08x\n", genpd->name, mask,
                 readl(rmobile_pd->base + PSTR));

        return 0;
}

static int __rmobile_pd_power_up(struct rmobile_pm_domain *rmobile_pd)
{
        unsigned int val, mask = BIT(rmobile_pd->bit_shift);
        int ret = 0;

        if (readl(rmobile_pd->base + PSTR) & mask)
                return ret;

        writel(mask, rmobile_pd->base + SWUCR);

        ret = readl_poll_timeout_atomic(rmobile_pd->base + SWUCR, val,
                                        (val & mask), PSTR_DELAY_US,
                                        PSTR_RETRIES * PSTR_DELAY_US);

        pr_debug("%s: Power on, 0x%08x -> PSTR = 0x%08x\n",
                 rmobile_pd->genpd.name, mask,
                 readl(rmobile_pd->base + PSTR));

        return ret;
}

static int rmobile_pd_power_up(struct generic_pm_domain *genpd)
{
        return __rmobile_pd_power_up(to_rmobile_pd(genpd));
}

static void rmobile_init_pm_domain(struct rmobile_pm_domain *rmobile_pd)
{
        struct generic_pm_domain *genpd = &rmobile_pd->genpd;
        struct dev_power_governor *gov = rmobile_pd->gov;

        genpd->flags |= GENPD_FLAG_PM_CLK | GENPD_FLAG_ACTIVE_WAKEUP |
                GENPD_FLAG_NO_STAY_ON;
        genpd->attach_dev = cpg_mstp_attach_dev;
        genpd->detach_dev = cpg_mstp_detach_dev;

        if (!(genpd->flags & GENPD_FLAG_ALWAYS_ON)) {
                genpd->power_off = rmobile_pd_power_down;
                genpd->power_on = rmobile_pd_power_up;
                __rmobile_pd_power_up(rmobile_pd);
        }

        pm_genpd_init(genpd, gov ? : &simple_qos_governor, false);
}

static int rmobile_pd_suspend_console(void)
{
        /*
         * Serial consoles make use of SCIF hardware located in this domain,
         * hence keep the power domain on if "no_console_suspend" is set.
         */
        return console_suspend_enabled ? 0 : -EBUSY;
}

enum pd_types {
        PD_NORMAL,
        PD_CPU,
        PD_CONSOLE,
        PD_DEBUG,
        PD_MEMCTL,
};

#define MAX_NUM_SPECIAL_PDS     16

static struct special_pd {
        struct device_node *pd;
        enum pd_types type;
} special_pds[MAX_NUM_SPECIAL_PDS] __initdata;

static unsigned int num_special_pds __initdata;

static const struct of_device_id special_ids[] __initconst = {
        { .compatible = "arm,coresight-etm3x", .data = (void *)PD_DEBUG },
        { .compatible = "renesas,dbsc-r8a73a4", .data = (void *)PD_MEMCTL, },
        { .compatible = "renesas,dbsc3-r8a7740", .data = (void *)PD_MEMCTL, },
        { .compatible = "renesas,sbsc-sh73a0", .data = (void *)PD_MEMCTL, },
        { /* sentinel */ },
};

static void __init add_special_pd(struct device_node *np, enum pd_types type)
{
        unsigned int i;
        struct device_node *pd;

        pd = of_parse_phandle(np, "power-domains", 0);
        if (!pd)
                return;

        for (i = 0; i < num_special_pds; i++)
                if (pd == special_pds[i].pd && type == special_pds[i].type) {
                        of_node_put(pd);
                        return;
                }

        if (num_special_pds == ARRAY_SIZE(special_pds)) {
                pr_warn("Too many special PM domains\n");
                of_node_put(pd);
                return;
        }

        pr_debug("Special PM domain %pOFn type %d for %pOF\n", pd, type, np);

        special_pds[num_special_pds].pd = pd;
        special_pds[num_special_pds].type = type;
        num_special_pds++;
}

static void __init get_special_pds(void)
{
        struct device_node *np;
        const struct of_device_id *id;

        /* PM domains containing CPUs */
        for_each_of_cpu_node(np)
                add_special_pd(np, PD_CPU);

        /* PM domain containing console */
        if (of_stdout)
                add_special_pd(of_stdout, PD_CONSOLE);

        /* PM domains containing other special devices */
        for_each_matching_node_and_match(np, special_ids, &id)
                add_special_pd(np, (uintptr_t)id->data);
}

static void __init put_special_pds(void)
{
        unsigned int i;

        for (i = 0; i < num_special_pds; i++)
                of_node_put(special_pds[i].pd);
}

static enum pd_types __init pd_type(const struct device_node *pd)
{
        unsigned int i;

        for (i = 0; i < num_special_pds; i++)
                if (pd == special_pds[i].pd)
                        return special_pds[i].type;

        return PD_NORMAL;
}

static void __init rmobile_setup_pm_domain(struct device_node *np,
                                           struct rmobile_pm_domain *pd)
{
        const char *name = pd->genpd.name;

        switch (pd_type(np)) {
        case PD_CPU:
                /*
                 * This domain contains the CPU core and therefore it should
                 * only be turned off if the CPU is not in use.
                 */
                pr_debug("PM domain %s contains CPU\n", name);
                pd->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
                break;

        case PD_CONSOLE:
                pr_debug("PM domain %s contains serial console\n", name);
                pd->gov = &pm_domain_always_on_gov;
                pd->suspend = rmobile_pd_suspend_console;
                break;

        case PD_DEBUG:
                /*
                 * This domain contains the Coresight-ETM hardware block and
                 * therefore it should only be turned off if the debug module
                 * is not in use.
                 */
                pr_debug("PM domain %s contains Coresight-ETM\n", name);
                pd->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
                break;

        case PD_MEMCTL:
                /*
                 * This domain contains a memory-controller and therefore it
                 * should only be turned off if memory is not in use.
                 */
                pr_debug("PM domain %s contains MEMCTL\n", name);
                pd->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
                break;

        case PD_NORMAL:
                if (pd->bit_shift == ~0) {
                        /* Top-level always-on domain */
                        pr_debug("PM domain %s is always-on domain\n", name);
                        pd->genpd.flags |= GENPD_FLAG_ALWAYS_ON;
                }
                break;
        }

        rmobile_init_pm_domain(pd);
}

static int __init rmobile_add_pm_domains(void __iomem *base,
                                         struct device_node *parent,
                                         struct generic_pm_domain *genpd_parent)
{
        for_each_child_of_node_scoped(parent, np) {
                struct rmobile_pm_domain *pd;
                u32 idx = ~0;

                if (of_property_read_u32(np, "reg", &idx)) {
                        /* always-on domain */
                }

                pd = kzalloc_obj(*pd);
                if (!pd)
                        return -ENOMEM;

                pd->genpd.name = np->name;
                pd->base = base;
                pd->bit_shift = idx;

                rmobile_setup_pm_domain(np, pd);
                if (genpd_parent)
                        pm_genpd_add_subdomain(genpd_parent, &pd->genpd);
                of_genpd_add_provider_simple(np, &pd->genpd);

                rmobile_add_pm_domains(base, np, &pd->genpd);
        }
        return 0;
}

static int __init rmobile_init_pm_domains(void)
{
        struct device_node *np, *pmd;
        bool scanned = false;
        void __iomem *base;
        int ret = 0;

        for_each_compatible_node(np, NULL, "renesas,sysc-rmobile") {
                base = of_iomap(np, 0);
                if (!base) {
                        pr_warn("%pOF cannot map reg 0\n", np);
                        continue;
                }

                pmd = of_get_child_by_name(np, "pm-domains");
                if (!pmd) {
                        iounmap(base);
                        pr_warn("%pOF lacks pm-domains node\n", np);
                        continue;
                }

                if (!scanned) {
                        /* Find PM domains containing special blocks */
                        get_special_pds();
                        scanned = true;
                }

                ret = rmobile_add_pm_domains(base, pmd, NULL);
                of_node_put(pmd);
                if (ret) {
                        of_node_put(np);
                        break;
                }

                fwnode_dev_initialized(of_fwnode_handle(np), true);
        }

        put_special_pds();

        return ret;
}
postcore_initcall(rmobile_init_pm_domains);