// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
// Copyright(c) 2015-2020 Intel Corporation.

/*
 * Bandwidth management algorithm based on 2^n gears
 *
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/soundwire/sdw.h>
#include "bus.h"

#define SDW_STRM_RATE_GROUPING          1

struct sdw_group_params {
        unsigned int rate;
        int full_bw;
        int payload_bw;
        int hwidth;
};

struct sdw_group {
        unsigned int count;
        unsigned int max_size;
        unsigned int *rates;
};

struct sdw_transport_data {
        int hstart;
        int hstop;
        int block_offset;
        int sub_block_offset;
};

static void sdw_compute_slave_ports(struct sdw_master_runtime *m_rt,
                                    struct sdw_transport_data *t_data)
{
        struct sdw_slave_runtime *s_rt = NULL;
        struct sdw_port_runtime *p_rt;
        int port_bo, sample_int;
        unsigned int rate, bps, ch = 0;
        unsigned int slave_total_ch;
        struct sdw_bus_params *b_params = &m_rt->bus->params;

        port_bo = t_data->block_offset;

        list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                rate = m_rt->stream->params.rate;
                bps = m_rt->stream->params.bps;
                sample_int = (m_rt->bus->params.curr_dr_freq / rate);
                slave_total_ch = 0;

                list_for_each_entry(p_rt, &s_rt->port_list, port_node) {
                        ch = sdw_ch_mask_to_ch(p_rt->ch_mask);

                        sdw_fill_xport_params(&p_rt->transport_params,
                                              p_rt->num, false,
                                              SDW_BLK_GRP_CNT_1,
                                              sample_int, port_bo, port_bo >> 8,
                                              t_data->hstart,
                                              t_data->hstop,
                                              SDW_BLK_PKG_PER_PORT, 0x0);

                        sdw_fill_port_params(&p_rt->port_params,
                                             p_rt->num, bps,
                                             SDW_PORT_FLOW_MODE_ISOCH,
                                             b_params->s_data_mode);

                        port_bo += bps * ch;
                        slave_total_ch += ch;
                }

                if (m_rt->direction == SDW_DATA_DIR_TX &&
                    m_rt->ch_count == slave_total_ch) {
                        /*
                         * Slave devices were configured to access all channels
                         * of the stream, which indicates that they operate in
                         * 'mirror mode'. Make sure we reset the port offset for
                         * the next device in the list
                         */
                        port_bo = t_data->block_offset;
                }
        }
}

static void sdw_compute_master_ports(struct sdw_master_runtime *m_rt,
                                     struct sdw_group_params *params,
                                     int port_bo, int hstop)
{
        struct sdw_transport_data t_data = {0};
        struct sdw_port_runtime *p_rt;
        struct sdw_bus *bus = m_rt->bus;
        struct sdw_bus_params *b_params = &bus->params;
        int sample_int, hstart = 0;
        unsigned int rate, bps, ch;

        rate = m_rt->stream->params.rate;
        bps = m_rt->stream->params.bps;
        ch = m_rt->ch_count;
        sample_int = (bus->params.curr_dr_freq / rate);

        if (rate != params->rate)
                return;

        t_data.hstop = hstop;
        hstart = hstop - params->hwidth + 1;
        t_data.hstart = hstart;

        list_for_each_entry(p_rt, &m_rt->port_list, port_node) {

                sdw_fill_xport_params(&p_rt->transport_params, p_rt->num,
                                      false, SDW_BLK_GRP_CNT_1, sample_int,
                                      port_bo, port_bo >> 8, hstart, hstop,
                                      SDW_BLK_PKG_PER_PORT, 0x0);

                sdw_fill_port_params(&p_rt->port_params,
                                     p_rt->num, bps,
                                     SDW_PORT_FLOW_MODE_ISOCH,
                                     b_params->m_data_mode);

                /* Check for first entry */
                if (!(p_rt == list_first_entry(&m_rt->port_list,
                                               struct sdw_port_runtime,
                                               port_node))) {
                        port_bo += bps * ch;
                        continue;
                }

                t_data.hstart = hstart;
                t_data.hstop = hstop;
                t_data.block_offset = port_bo;
                t_data.sub_block_offset = 0;
                port_bo += bps * ch;
        }

        sdw_compute_slave_ports(m_rt, &t_data);
}

static void _sdw_compute_port_params(struct sdw_bus *bus,
                                     struct sdw_group_params *params, int count)
{
        struct sdw_master_runtime *m_rt;
        int hstop = bus->params.col - 1;
        int block_offset, port_bo, i;

        /* Run loop for all groups to compute transport parameters */
        for (i = 0; i < count; i++) {
                port_bo = 1;
                block_offset = 1;

                list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {
                        sdw_compute_master_ports(m_rt, &params[i],
                                                 port_bo, hstop);

                        block_offset += m_rt->ch_count *
                                        m_rt->stream->params.bps;
                        port_bo = block_offset;
                }

                hstop = hstop - params[i].hwidth;
        }
}

static int sdw_compute_group_params(struct sdw_bus *bus,
                                    struct sdw_group_params *params,
                                    int *rates, int count)
{
        struct sdw_master_runtime *m_rt;
        int sel_col = bus->params.col;
        unsigned int rate, bps, ch;
        int i, column_needed = 0;

        /* Calculate bandwidth per group */
        for (i = 0; i < count; i++) {
                params[i].rate = rates[i];
                params[i].full_bw = bus->params.curr_dr_freq / params[i].rate;
        }

        list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {
                rate = m_rt->stream->params.rate;
                bps = m_rt->stream->params.bps;
                ch = m_rt->ch_count;

                for (i = 0; i < count; i++) {
                        if (rate == params[i].rate)
                                params[i].payload_bw += bps * ch;
                }
        }

        for (i = 0; i < count; i++) {
                params[i].hwidth = (sel_col *
                        params[i].payload_bw + params[i].full_bw - 1) /
                        params[i].full_bw;

                column_needed += params[i].hwidth;
        }

        if (column_needed > sel_col - 1)
                return -EINVAL;

        return 0;
}

static int sdw_add_element_group_count(struct sdw_group *group,
                                       unsigned int rate)
{
        int num = group->count;
        int i;

        for (i = 0; i <= num; i++) {
                if (rate == group->rates[i])
                        break;

                if (i != num)
                        continue;

                if (group->count >= group->max_size) {
                        unsigned int *rates;

                        group->max_size += 1;
                        rates = krealloc(group->rates,
                                         (sizeof(int) * group->max_size),
                                         GFP_KERNEL);
                        if (!rates)
                                return -ENOMEM;
                        group->rates = rates;
                }

                group->rates[group->count++] = rate;
        }

        return 0;
}

static int sdw_get_group_count(struct sdw_bus *bus,
                               struct sdw_group *group)
{
        struct sdw_master_runtime *m_rt;
        unsigned int rate;
        int ret = 0;

        group->count = 0;
        group->max_size = SDW_STRM_RATE_GROUPING;
        group->rates = kcalloc(group->max_size, sizeof(int), GFP_KERNEL);
        if (!group->rates)
                return -ENOMEM;

        list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {
                rate = m_rt->stream->params.rate;
                if (m_rt == list_first_entry(&bus->m_rt_list,
                                             struct sdw_master_runtime,
                                             bus_node)) {
                        group->rates[group->count++] = rate;

                } else {
                        ret = sdw_add_element_group_count(group, rate);
                        if (ret < 0) {
                                kfree(group->rates);
                                return ret;
                        }
                }
        }

        return ret;
}

/**
 * sdw_compute_port_params: Compute transport and port parameters
 *
 * @bus: SDW Bus instance
 */
static int sdw_compute_port_params(struct sdw_bus *bus)
{
        struct sdw_group_params *params = NULL;
        struct sdw_group group;
        int ret;

        ret = sdw_get_group_count(bus, &group);
        if (ret < 0)
                return ret;

        if (group.count == 0)
                goto out;

        params = kcalloc(group.count, sizeof(*params), GFP_KERNEL);
        if (!params) {
                ret = -ENOMEM;
                goto out;
        }

        /* Compute transport parameters for grouped streams */
        ret = sdw_compute_group_params(bus, params,
                                       &group.rates[0], group.count);
        if (ret < 0)
                goto free_params;

        _sdw_compute_port_params(bus, params, group.count);

free_params:
        kfree(params);
out:
        kfree(group.rates);

        return ret;
}

static int sdw_select_row_col(struct sdw_bus *bus, int clk_freq)
{
        struct sdw_master_prop *prop = &bus->prop;
        int frame_int, frame_freq;
        int r, c;

        for (c = 0; c < SDW_FRAME_COLS; c++) {
                for (r = 0; r < SDW_FRAME_ROWS; r++) {
                        if (sdw_rows[r] != prop->default_row ||
                            sdw_cols[c] != prop->default_col)
                                continue;

                        frame_int = sdw_rows[r] * sdw_cols[c];
                        frame_freq = clk_freq / frame_int;

                        if ((clk_freq - (frame_freq * SDW_FRAME_CTRL_BITS)) <
                            bus->params.bandwidth)
                                continue;

                        bus->params.row = sdw_rows[r];
                        bus->params.col = sdw_cols[c];
                        return 0;
                }
        }

        return -EINVAL;
}

/**
 * sdw_compute_bus_params: Compute bus parameters
 *
 * @bus: SDW Bus instance
 */
static int sdw_compute_bus_params(struct sdw_bus *bus)
{
        unsigned int max_dr_freq, curr_dr_freq = 0;
        struct sdw_master_prop *mstr_prop = &bus->prop;
        int i, clk_values, ret;
        bool is_gear = false;
        u32 *clk_buf;

        if (mstr_prop->num_clk_gears) {
                clk_values = mstr_prop->num_clk_gears;
                clk_buf = mstr_prop->clk_gears;
                is_gear = true;
        } else if (mstr_prop->num_clk_freq) {
                clk_values = mstr_prop->num_clk_freq;
                clk_buf = mstr_prop->clk_freq;
        } else {
                clk_values = 1;
                clk_buf = NULL;
        }

        max_dr_freq = mstr_prop->max_clk_freq * SDW_DOUBLE_RATE_FACTOR;

        for (i = 0; i < clk_values; i++) {
                if (!clk_buf)
                        curr_dr_freq = max_dr_freq;
                else
                        curr_dr_freq = (is_gear) ?
                                (max_dr_freq >>  clk_buf[i]) :
                                clk_buf[i] * SDW_DOUBLE_RATE_FACTOR;

                if (curr_dr_freq <= bus->params.bandwidth)
                        continue;

                break;

                /*
                 * TODO: Check all the Slave(s) port(s) audio modes and find
                 * whether given clock rate is supported with glitchless
                 * transition.
                 */
        }

        if (i == clk_values) {
                dev_err(bus->dev, "%s: could not find clock value for bandwidth %d\n",
                        __func__, bus->params.bandwidth);
                return -EINVAL;
        }

        ret = sdw_select_row_col(bus, curr_dr_freq);
        if (ret < 0) {
                dev_err(bus->dev, "%s: could not find frame configuration for bus dr_freq %d\n",
                        __func__, curr_dr_freq);
                return -EINVAL;
        }

        bus->params.curr_dr_freq = curr_dr_freq;
        return 0;
}

/**
 * sdw_compute_params: Compute bus, transport and port parameters
 *
 * @bus: SDW Bus instance
 */
int sdw_compute_params(struct sdw_bus *bus)
{
        int ret;

        /* Computes clock frequency, frame shape and frame frequency */
        ret = sdw_compute_bus_params(bus);
        if (ret < 0)
                return ret;

        /* Compute transport and port params */
        ret = sdw_compute_port_params(bus);
        if (ret < 0) {
                dev_err(bus->dev, "Compute transport params failed: %d\n", ret);
                return ret;
        }

        return 0;
}
EXPORT_SYMBOL(sdw_compute_params);

MODULE_LICENSE("Dual BSD/GPL");
MODULE_DESCRIPTION("SoundWire Generic Bandwidth Allocation");