// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2019-2025 NVIDIA CORPORATION.  All rights reserved.
 */

#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>

#include <soc/tegra/bpmp.h>
#include "mc.h"

struct tegra186_emc_dvfs {
        unsigned long latency;
        unsigned long rate;
};

struct tegra186_emc {
        struct tegra_bpmp *bpmp;
        struct device *dev;
        struct clk *clk;

        struct tegra186_emc_dvfs *dvfs;
        unsigned int num_dvfs;

        struct {
                struct dentry *root;
                unsigned long min_rate;
                unsigned long max_rate;
        } debugfs;

        struct icc_provider provider;
};

/*
 * debugfs interface
 *
 * The memory controller driver exposes some files in debugfs that can be used
 * to control the EMC frequency. The top-level directory can be found here:
 *
 *   /sys/kernel/debug/emc
 *
 * It contains the following files:
 *
 *   - available_rates: This file contains a list of valid, space-separated
 *     EMC frequencies.
 *
 *   - min_rate: Writing a value to this file sets the given frequency as the
 *       floor of the permitted range. If this is higher than the currently
 *       configured EMC frequency, this will cause the frequency to be
 *       increased so that it stays within the valid range.
 *
 *   - max_rate: Similarily to the min_rate file, writing a value to this file
 *       sets the given frequency as the ceiling of the permitted range. If
 *       the value is lower than the currently configured EMC frequency, this
 *       will cause the frequency to be decreased so that it stays within the
 *       valid range.
 */

static bool tegra186_emc_validate_rate(struct tegra186_emc *emc,
                                       unsigned long rate)
{
        unsigned int i;

        for (i = 0; i < emc->num_dvfs; i++)
                if (rate == emc->dvfs[i].rate)
                        return true;

        return false;
}

static int tegra186_emc_debug_available_rates_show(struct seq_file *s,
                                                   void *data)
{
        struct tegra186_emc *emc = s->private;
        const char *prefix = "";
        unsigned int i;

        for (i = 0; i < emc->num_dvfs; i++) {
                seq_printf(s, "%s%lu", prefix, emc->dvfs[i].rate);
                prefix = " ";
        }

        seq_puts(s, "\n");

        return 0;
}
DEFINE_SHOW_ATTRIBUTE(tegra186_emc_debug_available_rates);

static int tegra186_emc_debug_min_rate_get(void *data, u64 *rate)
{
        struct tegra186_emc *emc = data;

        *rate = emc->debugfs.min_rate;

        return 0;
}

static int tegra186_emc_debug_min_rate_set(void *data, u64 rate)
{
        struct tegra186_emc *emc = data;
        int err;

        if (!tegra186_emc_validate_rate(emc, rate))
                return -EINVAL;

        err = clk_set_min_rate(emc->clk, rate);
        if (err < 0)
                return err;

        emc->debugfs.min_rate = rate;

        return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(tegra186_emc_debug_min_rate_fops,
                          tegra186_emc_debug_min_rate_get,
                          tegra186_emc_debug_min_rate_set, "%llu\n");

static int tegra186_emc_debug_max_rate_get(void *data, u64 *rate)
{
        struct tegra186_emc *emc = data;

        *rate = emc->debugfs.max_rate;

        return 0;
}

static int tegra186_emc_debug_max_rate_set(void *data, u64 rate)
{
        struct tegra186_emc *emc = data;
        int err;

        if (!tegra186_emc_validate_rate(emc, rate))
                return -EINVAL;

        err = clk_set_max_rate(emc->clk, rate);
        if (err < 0)
                return err;

        emc->debugfs.max_rate = rate;

        return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(tegra186_emc_debug_max_rate_fops,
                          tegra186_emc_debug_max_rate_get,
                          tegra186_emc_debug_max_rate_set, "%llu\n");

static int tegra186_emc_get_emc_dvfs_latency(struct tegra186_emc *emc)
{
        struct mrq_emc_dvfs_latency_response response;
        struct tegra_bpmp_message msg;
        unsigned int i;
        int err;

        memset(&msg, 0, sizeof(msg));
        msg.mrq = MRQ_EMC_DVFS_LATENCY;
        msg.tx.data = NULL;
        msg.tx.size = 0;
        msg.rx.data = &response;
        msg.rx.size = sizeof(response);

        err = tegra_bpmp_transfer(emc->bpmp, &msg);
        if (err < 0) {
                dev_err(emc->dev, "failed to EMC DVFS pairs: %d\n", err);
                return err;
        }
        if (msg.rx.ret < 0) {
                dev_err(emc->dev, "EMC DVFS MRQ failed: %d (BPMP error code)\n", msg.rx.ret);
                return -EINVAL;
        }

        emc->debugfs.min_rate = ULONG_MAX;
        emc->debugfs.max_rate = 0;

        emc->num_dvfs = response.num_pairs;

        emc->dvfs = devm_kmalloc_array(emc->dev, emc->num_dvfs, sizeof(*emc->dvfs), GFP_KERNEL);
        if (!emc->dvfs)
                return -ENOMEM;

        dev_dbg(emc->dev, "%u DVFS pairs:\n", emc->num_dvfs);

        for (i = 0; i < emc->num_dvfs; i++) {
                emc->dvfs[i].rate = response.pairs[i].freq * 1000;
                emc->dvfs[i].latency = response.pairs[i].latency;

                if (emc->dvfs[i].rate < emc->debugfs.min_rate)
                        emc->debugfs.min_rate = emc->dvfs[i].rate;

                if (emc->dvfs[i].rate > emc->debugfs.max_rate)
                        emc->debugfs.max_rate = emc->dvfs[i].rate;

                dev_dbg(emc->dev, "  %2u: %lu Hz -> %lu us\n", i,
                        emc->dvfs[i].rate, emc->dvfs[i].latency);
        }

        err = clk_set_rate_range(emc->clk, emc->debugfs.min_rate, emc->debugfs.max_rate);
        if (err < 0) {
                dev_err(emc->dev, "failed to set rate range [%lu-%lu] for %pC\n",
                        emc->debugfs.min_rate, emc->debugfs.max_rate, emc->clk);
                return err;
        }

        emc->debugfs.root = debugfs_create_dir("emc", NULL);
        debugfs_create_file("available_rates", 0444, emc->debugfs.root, emc,
                            &tegra186_emc_debug_available_rates_fops);
        debugfs_create_file("min_rate", 0644, emc->debugfs.root, emc,
                            &tegra186_emc_debug_min_rate_fops);
        debugfs_create_file("max_rate", 0644, emc->debugfs.root, emc,
                            &tegra186_emc_debug_max_rate_fops);

        return 0;
}

/*
 * tegra186_emc_icc_set_bw() - Set BW api for EMC provider
 * @src: ICC node for External Memory Controller (EMC)
 * @dst: ICC node for External Memory (DRAM)
 *
 * Do nothing here as info to BPMP-FW is now passed in the BW set function
 * of the MC driver. BPMP-FW sets the final Freq based on the passed values.
 */
static int tegra186_emc_icc_set_bw(struct icc_node *src, struct icc_node *dst)
{
        return 0;
}

static struct icc_node *
tegra186_emc_of_icc_xlate(const struct of_phandle_args *spec, void *data)
{
        struct icc_provider *provider = data;
        struct icc_node *node;

        /* External Memory is the only possible ICC route */
        list_for_each_entry(node, &provider->nodes, node_list) {
                if (node->id != TEGRA_ICC_EMEM)
                        continue;

                return node;
        }

        return ERR_PTR(-EPROBE_DEFER);
}

static int tegra186_emc_icc_get_init_bw(struct icc_node *node, u32 *avg, u32 *peak)
{
        *avg = 0;
        *peak = 0;

        return 0;
}

static int tegra186_emc_interconnect_init(struct tegra186_emc *emc)
{
        struct tegra_mc *mc = dev_get_drvdata(emc->dev->parent);
        const struct tegra_mc_soc *soc = mc->soc;
        struct icc_node *node;
        int err;

        emc->provider.dev = emc->dev;
        emc->provider.set = tegra186_emc_icc_set_bw;
        emc->provider.data = &emc->provider;
        emc->provider.aggregate = soc->icc_ops->aggregate;
        emc->provider.xlate = tegra186_emc_of_icc_xlate;
        emc->provider.get_bw = tegra186_emc_icc_get_init_bw;

        icc_provider_init(&emc->provider);

        /* create External Memory Controller node */
        node = icc_node_create(TEGRA_ICC_EMC);
        if (IS_ERR(node))
                return PTR_ERR(node);

        node->name = "External Memory Controller";
        icc_node_add(node, &emc->provider);

        /* link External Memory Controller to External Memory (DRAM) */
        err = icc_link_create(node, TEGRA_ICC_EMEM);
        if (err)
                goto remove_nodes;

        /* create External Memory node */
        node = icc_node_create(TEGRA_ICC_EMEM);
        if (IS_ERR(node)) {
                err = PTR_ERR(node);
                goto remove_nodes;
        }

        node->name = "External Memory (DRAM)";
        icc_node_add(node, &emc->provider);

        err = icc_provider_register(&emc->provider);
        if (err)
                goto remove_nodes;

        return 0;

remove_nodes:
        icc_nodes_remove(&emc->provider);

        return dev_err_probe(emc->dev, err, "failed to initialize ICC\n");
}

static int tegra186_emc_probe(struct platform_device *pdev)
{
        struct tegra_mc *mc = dev_get_drvdata(pdev->dev.parent);
        struct tegra186_emc *emc;
        int err;

        emc = devm_kzalloc(&pdev->dev, sizeof(*emc), GFP_KERNEL);
        if (!emc)
                return -ENOMEM;

        emc->bpmp = tegra_bpmp_get(&pdev->dev);
        if (IS_ERR(emc->bpmp))
                return dev_err_probe(&pdev->dev, PTR_ERR(emc->bpmp),
                                     "failed to get BPMP\n");

        emc->clk = devm_clk_get(&pdev->dev, "emc");
        if (IS_ERR(emc->clk)) {
                err = dev_err_probe(&pdev->dev, PTR_ERR(emc->clk),
                                    "failed to get EMC clock\n");
                goto put_bpmp;
        }

        platform_set_drvdata(pdev, emc);
        emc->dev = &pdev->dev;

        if (tegra_bpmp_mrq_is_supported(emc->bpmp, MRQ_EMC_DVFS_LATENCY)) {
                err = tegra186_emc_get_emc_dvfs_latency(emc);
                if (err)
                        goto put_bpmp;
        }

        if (mc && mc->soc->icc_ops) {
                if (tegra_bpmp_mrq_is_supported(emc->bpmp, MRQ_BWMGR_INT)) {
                        mc->bwmgr_mrq_supported = true;

                        /*
                         * MC driver probe can't get BPMP reference as it gets probed
                         * earlier than BPMP. So, save the BPMP ref got from the EMC
                         * DT node in the mc->bpmp and use it in MC's icc_set hook.
                         */
                        mc->bpmp = emc->bpmp;
                        barrier();
                }

                /*
                 * Initialize the ICC even if BPMP-FW doesn't support 'MRQ_BWMGR_INT'.
                 * Use the flag 'mc->bwmgr_mrq_supported' within MC driver and return
                 * EINVAL instead of passing the request to BPMP-FW later when the BW
                 * request is made by client with 'icc_set_bw()' call.
                 */
                err = tegra186_emc_interconnect_init(emc);
                if (err) {
                        mc->bpmp = NULL;
                        goto put_bpmp;
                }
        }

        return 0;

put_bpmp:
        tegra_bpmp_put(emc->bpmp);
        return err;
}

static void tegra186_emc_remove(struct platform_device *pdev)
{
        struct tegra_mc *mc = dev_get_drvdata(pdev->dev.parent);
        struct tegra186_emc *emc = platform_get_drvdata(pdev);

        debugfs_remove_recursive(emc->debugfs.root);

        mc->bpmp = NULL;
        tegra_bpmp_put(emc->bpmp);
}

static const struct of_device_id tegra186_emc_of_match[] = {
#if defined(CONFIG_ARCH_TEGRA_186_SOC)
        { .compatible = "nvidia,tegra186-emc" },
#endif
#if defined(CONFIG_ARCH_TEGRA_194_SOC)
        { .compatible = "nvidia,tegra194-emc" },
#endif
#if defined(CONFIG_ARCH_TEGRA_234_SOC)
        { .compatible = "nvidia,tegra234-emc" },
#endif
#if defined(CONFIG_ARCH_TEGRA_264_SOC)
        { .compatible = "nvidia,tegra264-emc" },
#endif
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, tegra186_emc_of_match);

static struct platform_driver tegra186_emc_driver = {
        .driver = {
                .name = "tegra186-emc",
                .of_match_table = tegra186_emc_of_match,
                .suppress_bind_attrs = true,
                .sync_state = icc_sync_state,
        },
        .probe = tegra186_emc_probe,
        .remove = tegra186_emc_remove,
};
module_platform_driver(tegra186_emc_driver);

MODULE_AUTHOR("Thierry Reding <treding@nvidia.com>");
MODULE_DESCRIPTION("NVIDIA Tegra186 External Memory Controller driver");