// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2020-2021, The Linux Foundation. All rights reserved.
 */

#include <asm/div64.h>
#include <linux/interconnect-provider.h>
#include <linux/list_sort.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>

#include <soc/qcom/rpmh.h>
#include <soc/qcom/tcs.h>

#include "bcm-voter.h"
#include "icc-rpmh.h"

static LIST_HEAD(bcm_voters);
static DEFINE_MUTEX(bcm_voter_lock);

/**
 * struct bcm_voter - Bus Clock Manager voter
 * @dev: reference to the device that communicates with the BCM
 * @np: reference to the device node to match bcm voters
 * @lock: mutex to protect commit and wake/sleep lists in the voter
 * @commit_list: list containing bcms to be committed to hardware
 * @ws_list: list containing bcms that have different wake/sleep votes
 * @voter_node: list of bcm voters
 * @tcs_wait: mask for which buckets require TCS completion
 */
struct bcm_voter {
        struct device *dev;
        struct device_node *np;
        struct mutex lock;
        struct list_head commit_list;
        struct list_head ws_list;
        struct list_head voter_node;
        u32 tcs_wait;
};

static int cmp_vcd(void *priv, const struct list_head *a, const struct list_head *b)
{
        const struct qcom_icc_bcm *bcm_a = list_entry(a, struct qcom_icc_bcm, list);
        const struct qcom_icc_bcm *bcm_b = list_entry(b, struct qcom_icc_bcm, list);

        return bcm_a->aux_data.vcd - bcm_b->aux_data.vcd;
}

static u64 bcm_div(u64 num, u32 base)
{
        /* Ensure that small votes aren't lost. */
        if (num && num < base)
                return 1;

        do_div(num, base);

        return num;
}

static void bcm_aggregate(struct qcom_icc_bcm *bcm)
{
        struct qcom_icc_node *node;
        size_t i, bucket;
        u64 agg_avg[QCOM_ICC_NUM_BUCKETS] = {0};
        u64 agg_peak[QCOM_ICC_NUM_BUCKETS] = {0};
        u64 temp;

        for (bucket = 0; bucket < QCOM_ICC_NUM_BUCKETS; bucket++) {
                for (i = 0; i < bcm->num_nodes; i++) {
                        node = bcm->nodes[i];
                        temp = bcm_div(node->sum_avg[bucket] * bcm->aux_data.width,
                                       node->buswidth * node->channels);
                        agg_avg[bucket] = max(agg_avg[bucket], temp);

                        temp = bcm_div(node->max_peak[bucket] * bcm->aux_data.width,
                                       node->buswidth);
                        agg_peak[bucket] = max(agg_peak[bucket], temp);
                }

                temp = agg_avg[bucket] * bcm->vote_scale;
                bcm->vote_x[bucket] = bcm_div(temp, bcm->aux_data.unit);

                temp = agg_peak[bucket] * bcm->vote_scale;
                bcm->vote_y[bucket] = bcm_div(temp, bcm->aux_data.unit);
        }

        if (bcm->keepalive && bcm->vote_x[QCOM_ICC_BUCKET_AMC] == 0 &&
            bcm->vote_y[QCOM_ICC_BUCKET_AMC] == 0) {
                bcm->vote_x[QCOM_ICC_BUCKET_AMC] = 1;
                bcm->vote_x[QCOM_ICC_BUCKET_WAKE] = 1;
                bcm->vote_y[QCOM_ICC_BUCKET_AMC] = 1;
                bcm->vote_y[QCOM_ICC_BUCKET_WAKE] = 1;
        }
}

static inline void tcs_cmd_gen(struct tcs_cmd *cmd, u64 vote_x, u64 vote_y,
                               u32 addr, bool commit, bool wait)
{
        bool valid = true;

        if (!cmd)
                return;

        memset(cmd, 0, sizeof(*cmd));

        if (vote_x == 0 && vote_y == 0)
                valid = false;

        if (vote_x > BCM_TCS_CMD_VOTE_MASK)
                vote_x = BCM_TCS_CMD_VOTE_MASK;

        if (vote_y > BCM_TCS_CMD_VOTE_MASK)
                vote_y = BCM_TCS_CMD_VOTE_MASK;

        cmd->addr = addr;
        cmd->data = BCM_TCS_CMD(commit, valid, vote_x, vote_y);

        /*
         * Set the wait for completion flag on command that need to be completed
         * before the next command.
         */
        cmd->wait = wait;
}

static void tcs_list_gen(struct bcm_voter *voter, int bucket,
                         struct tcs_cmd tcs_list[MAX_VCD],
                         int n[MAX_VCD + 1])
{
        struct list_head *bcm_list = &voter->commit_list;
        struct qcom_icc_bcm *bcm;
        bool commit, wait;
        size_t idx = 0, batch = 0, cur_vcd_size = 0;

        memset(n, 0, sizeof(int) * (MAX_VCD + 1));

        list_for_each_entry(bcm, bcm_list, list) {
                commit = false;
                cur_vcd_size++;
                if ((list_is_last(&bcm->list, bcm_list)) ||
                    bcm->aux_data.vcd != list_next_entry(bcm, list)->aux_data.vcd) {
                        commit = true;
                        cur_vcd_size = 0;
                }

                wait = commit && (voter->tcs_wait & BIT(bucket));

                tcs_cmd_gen(&tcs_list[idx], bcm->vote_x[bucket],
                            bcm->vote_y[bucket], bcm->addr, commit, wait);
                idx++;
                n[batch]++;
                /*
                 * Batch the BCMs in such a way that we do not split them in
                 * multiple payloads when they are under the same VCD. This is
                 * to ensure that every BCM is committed since we only set the
                 * commit bit on the last BCM request of every VCD.
                 */
                if (n[batch] >= MAX_RPMH_PAYLOAD) {
                        if (!commit) {
                                n[batch] -= cur_vcd_size;
                                n[batch + 1] = cur_vcd_size;
                        }
                        batch++;
                }
        }
}

/**
 * of_bcm_voter_get - gets a bcm voter handle from DT node
 * @dev: device pointer for the consumer device
 * @name: name for the bcm voter device
 *
 * This function will match a device_node pointer for the phandle
 * specified in the device DT and return a bcm_voter handle on success.
 *
 * Returns bcm_voter pointer or ERR_PTR() on error. EPROBE_DEFER is returned
 * when matching bcm voter is yet to be found.
 */
struct bcm_voter *of_bcm_voter_get(struct device *dev, const char *name)
{
        struct bcm_voter *voter = ERR_PTR(-EPROBE_DEFER);
        struct bcm_voter *temp;
        struct device_node *np, *node;
        int idx = 0;

        if (!dev || !dev->of_node)
                return ERR_PTR(-ENODEV);

        np = dev->of_node;

        if (name) {
                idx = of_property_match_string(np, "qcom,bcm-voter-names", name);
                if (idx < 0)
                        return ERR_PTR(idx);
        }

        node = of_parse_phandle(np, "qcom,bcm-voters", idx);

        mutex_lock(&bcm_voter_lock);
        list_for_each_entry(temp, &bcm_voters, voter_node) {
                if (temp->np == node) {
                        voter = temp;
                        break;
                }
        }
        mutex_unlock(&bcm_voter_lock);

        of_node_put(node);
        return voter;
}
EXPORT_SYMBOL_GPL(of_bcm_voter_get);

/**
 * qcom_icc_bcm_voter_add - queues up the bcm nodes that require updates
 * @voter: voter that the bcms are being added to
 * @bcm: bcm to add to the commit and wake sleep list
 */
void qcom_icc_bcm_voter_add(struct bcm_voter *voter, struct qcom_icc_bcm *bcm)
{
        if (!voter)
                return;

        mutex_lock(&voter->lock);
        if (list_empty(&bcm->list))
                list_add_tail(&bcm->list, &voter->commit_list);

        if (list_empty(&bcm->ws_list))
                list_add_tail(&bcm->ws_list, &voter->ws_list);

        mutex_unlock(&voter->lock);
}
EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_add);

/**
 * qcom_icc_bcm_voter_commit - generates and commits tcs cmds based on bcms
 * @voter: voter that needs flushing
 *
 * This function generates a set of AMC commands and flushes to the BCM device
 * associated with the voter. It conditionally generate WAKE and SLEEP commands
 * based on deltas between WAKE/SLEEP requirements. The ws_list persists
 * through multiple commit requests and bcm nodes are removed only when the
 * requirements for WAKE matches SLEEP.
 *
 * Returns 0 on success, or an appropriate error code otherwise.
 */
int qcom_icc_bcm_voter_commit(struct bcm_voter *voter)
{
        struct qcom_icc_bcm *bcm;
        struct qcom_icc_bcm *bcm_tmp;
        int commit_idx[MAX_VCD + 1];
        struct tcs_cmd cmds[MAX_BCMS];
        int ret = 0;

        if (!voter)
                return 0;

        mutex_lock(&voter->lock);
        list_for_each_entry(bcm, &voter->commit_list, list)
                bcm_aggregate(bcm);

        /*
         * Pre sort the BCMs based on VCD for ease of generating a command list
         * that groups the BCMs with the same VCD together. VCDs are numbered
         * with lowest being the most expensive time wise, ensuring that
         * those commands are being sent the earliest in the queue. This needs
         * to be sorted every commit since we can't guarantee the order in which
         * the BCMs are added to the list.
         */
        list_sort(NULL, &voter->commit_list, cmp_vcd);

        /*
         * Construct the command list based on a pre ordered list of BCMs
         * based on VCD.
         */
        tcs_list_gen(voter, QCOM_ICC_BUCKET_AMC, cmds, commit_idx);
        if (!commit_idx[0])
                goto out;

        rpmh_invalidate(voter->dev);

        ret = rpmh_write_batch(voter->dev, RPMH_ACTIVE_ONLY_STATE,
                               cmds, commit_idx);
        if (ret) {
                pr_err("Error sending AMC RPMH requests (%d)\n", ret);
                goto out;
        }

        list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
                list_del_init(&bcm->list);

        list_for_each_entry_safe(bcm, bcm_tmp, &voter->ws_list, ws_list) {
                /*
                 * Only generate WAKE and SLEEP commands if a resource's
                 * requirements change as the execution environment transitions
                 * between different power states.
                 */
                if (bcm->vote_x[QCOM_ICC_BUCKET_WAKE] !=
                    bcm->vote_x[QCOM_ICC_BUCKET_SLEEP] ||
                    bcm->vote_y[QCOM_ICC_BUCKET_WAKE] !=
                    bcm->vote_y[QCOM_ICC_BUCKET_SLEEP])
                        list_add_tail(&bcm->list, &voter->commit_list);
                else
                        list_del_init(&bcm->ws_list);
        }

        if (list_empty(&voter->commit_list))
                goto out;

        list_sort(NULL, &voter->commit_list, cmp_vcd);

        tcs_list_gen(voter, QCOM_ICC_BUCKET_WAKE, cmds, commit_idx);

        ret = rpmh_write_batch(voter->dev, RPMH_WAKE_ONLY_STATE, cmds, commit_idx);
        if (ret) {
                pr_err("Error sending WAKE RPMH requests (%d)\n", ret);
                goto out;
        }

        tcs_list_gen(voter, QCOM_ICC_BUCKET_SLEEP, cmds, commit_idx);

        ret = rpmh_write_batch(voter->dev, RPMH_SLEEP_STATE, cmds, commit_idx);
        if (ret) {
                pr_err("Error sending SLEEP RPMH requests (%d)\n", ret);
                goto out;
        }

out:
        list_for_each_entry_safe(bcm, bcm_tmp, &voter->commit_list, list)
                list_del_init(&bcm->list);

        mutex_unlock(&voter->lock);
        return ret;
}
EXPORT_SYMBOL_GPL(qcom_icc_bcm_voter_commit);

static int qcom_icc_bcm_voter_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct bcm_voter *voter;

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

        voter->dev = &pdev->dev;
        voter->np = np;

        if (of_property_read_u32(np, "qcom,tcs-wait", &voter->tcs_wait))
                voter->tcs_wait = QCOM_ICC_TAG_ACTIVE_ONLY;

        mutex_init(&voter->lock);
        INIT_LIST_HEAD(&voter->commit_list);
        INIT_LIST_HEAD(&voter->ws_list);

        mutex_lock(&bcm_voter_lock);
        list_add_tail(&voter->voter_node, &bcm_voters);
        mutex_unlock(&bcm_voter_lock);

        return 0;
}

static const struct of_device_id bcm_voter_of_match[] = {
        { .compatible = "qcom,bcm-voter" },
        { }
};
MODULE_DEVICE_TABLE(of, bcm_voter_of_match);

static struct platform_driver qcom_icc_bcm_voter_driver = {
        .probe = qcom_icc_bcm_voter_probe,
        .driver = {
                .name           = "bcm_voter",
                .of_match_table = bcm_voter_of_match,
        },
};
module_platform_driver(qcom_icc_bcm_voter_driver);

MODULE_AUTHOR("David Dai <daidavid1@codeaurora.org>");
MODULE_DESCRIPTION("Qualcomm BCM Voter interconnect driver");
MODULE_LICENSE("GPL v2");