// SPDX-License-Identifier: GPL-2.0-only
/*
 * OMAP IOMMU quirks for various TI SoCs
 *
 * Copyright (C) 2015-2019 Texas Instruments Incorporated - https://www.ti.com/
 *      Suman Anna <s-anna@ti.com>
 */

#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/list.h>

#include "clockdomain.h"
#include "powerdomain.h"
#include "common.h"

struct pwrdm_link {
        struct device *dev;
        struct powerdomain *pwrdm;
        struct list_head node;
};

static DEFINE_SPINLOCK(iommu_lock);
static struct clockdomain *emu_clkdm;
static atomic_t emu_count;

static void omap_iommu_dra7_emu_swsup_config(struct platform_device *pdev,
                                             bool enable)
{
        struct device_node *np = pdev->dev.of_node;
        unsigned long flags;

        if (!of_device_is_compatible(np, "ti,dra7-dsp-iommu"))
                return;

        if (!emu_clkdm) {
                emu_clkdm = clkdm_lookup("emu_clkdm");
                if (WARN_ON_ONCE(!emu_clkdm))
                        return;
        }

        spin_lock_irqsave(&iommu_lock, flags);

        if (enable && (atomic_inc_return(&emu_count) == 1))
                clkdm_deny_idle(emu_clkdm);
        else if (!enable && (atomic_dec_return(&emu_count) == 0))
                clkdm_allow_idle(emu_clkdm);

        spin_unlock_irqrestore(&iommu_lock, flags);
}

static struct powerdomain *_get_pwrdm(struct device *dev)
{
        struct clk *clk;
        struct clk_hw_omap *hwclk;
        struct clockdomain *clkdm;
        struct powerdomain *pwrdm = NULL;
        struct pwrdm_link *entry;
        unsigned long flags;
        static LIST_HEAD(cache);

        spin_lock_irqsave(&iommu_lock, flags);

        list_for_each_entry(entry, &cache, node) {
                if (entry->dev == dev) {
                        pwrdm = entry->pwrdm;
                        break;
                }
        }

        spin_unlock_irqrestore(&iommu_lock, flags);

        if (pwrdm)
                return pwrdm;

        clk = of_clk_get(dev->of_node->parent, 0);
        if (IS_ERR(clk)) {
                dev_err(dev, "no fck found\n");
                return NULL;
        }

        hwclk = to_clk_hw_omap(__clk_get_hw(clk));
        clk_put(clk);
        if (!hwclk || !hwclk->clkdm_name) {
                dev_err(dev, "no hwclk data\n");
                return NULL;
        }

        clkdm = clkdm_lookup(hwclk->clkdm_name);
        if (!clkdm) {
                dev_err(dev, "clkdm not found: %s\n", hwclk->clkdm_name);
                return NULL;
        }

        pwrdm = clkdm_get_pwrdm(clkdm);
        if (!pwrdm) {
                dev_err(dev, "pwrdm not found: %s\n", clkdm->name);
                return NULL;
        }

        entry = kmalloc_obj(*entry);
        if (entry) {
                entry->dev = dev;
                entry->pwrdm = pwrdm;
                spin_lock_irqsave(&iommu_lock, flags);
                list_add(&entry->node, &cache);
                spin_unlock_irqrestore(&iommu_lock, flags);
        }

        return pwrdm;
}

int omap_iommu_set_pwrdm_constraint(struct platform_device *pdev, bool request,
                                    u8 *pwrst)
{
        struct powerdomain *pwrdm;
        u8 next_pwrst;
        int ret = 0;

        pwrdm = _get_pwrdm(&pdev->dev);
        if (!pwrdm)
                return -ENODEV;

        if (request) {
                *pwrst = pwrdm_read_next_pwrst(pwrdm);
                omap_iommu_dra7_emu_swsup_config(pdev, true);
        }

        if (*pwrst > PWRDM_POWER_RET)
                goto out;

        next_pwrst = request ? PWRDM_POWER_ON : *pwrst;

        ret = pwrdm_set_next_pwrst(pwrdm, next_pwrst);

out:
        if (!request)
                omap_iommu_dra7_emu_swsup_config(pdev, false);

        return ret;
}