Documentation: Add documentation for Processor MMIO Stale Data

[mirror_ubuntu-jammy-kernel.git] / drivers / soundwire / stream.c

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-18 Intel Corporation.

/*
 *  stream.c - SoundWire Bus stream operations.
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
#include <sound/soc.h>
#include "bus.h"

/*
 * Array of supported rows and columns as per MIPI SoundWire Specification 1.1
 *
 * The rows are arranged as per the array index value programmed
 * in register. The index 15 has dummy value 0 in order to fill hole.
 */
int sdw_rows[SDW_FRAME_ROWS] = {48, 50, 60, 64, 75, 80, 125, 147,
                        96, 100, 120, 128, 150, 160, 250, 0,
                        192, 200, 240, 256, 72, 144, 90, 180};
EXPORT_SYMBOL(sdw_rows);

int sdw_cols[SDW_FRAME_COLS] = {2, 4, 6, 8, 10, 12, 14, 16};
EXPORT_SYMBOL(sdw_cols);

int sdw_find_col_index(int col)
{
        int i;

        for (i = 0; i < SDW_FRAME_COLS; i++) {
                if (sdw_cols[i] == col)
                        return i;
        }

        pr_warn("Requested column not found, selecting lowest column no: 2\n");
        return 0;
}
EXPORT_SYMBOL(sdw_find_col_index);

int sdw_find_row_index(int row)
{
        int i;

        for (i = 0; i < SDW_FRAME_ROWS; i++) {
                if (sdw_rows[i] == row)
                        return i;
        }

        pr_warn("Requested row not found, selecting lowest row no: 48\n");
        return 0;
}
EXPORT_SYMBOL(sdw_find_row_index);

static int _sdw_program_slave_port_params(struct sdw_bus *bus,
                                          struct sdw_slave *slave,
                                          struct sdw_transport_params *t_params,
                                          enum sdw_dpn_type type)
{
        u32 addr1, addr2, addr3, addr4;
        int ret;
        u16 wbuf;

        if (bus->params.next_bank) {
                addr1 = SDW_DPN_OFFSETCTRL2_B1(t_params->port_num);
                addr2 = SDW_DPN_BLOCKCTRL3_B1(t_params->port_num);
                addr3 = SDW_DPN_SAMPLECTRL2_B1(t_params->port_num);
                addr4 = SDW_DPN_HCTRL_B1(t_params->port_num);
        } else {
                addr1 = SDW_DPN_OFFSETCTRL2_B0(t_params->port_num);
                addr2 = SDW_DPN_BLOCKCTRL3_B0(t_params->port_num);
                addr3 = SDW_DPN_SAMPLECTRL2_B0(t_params->port_num);
                addr4 = SDW_DPN_HCTRL_B0(t_params->port_num);
        }

        /* Program DPN_OffsetCtrl2 registers */
        ret = sdw_write(slave, addr1, t_params->offset2);
        if (ret < 0) {
                dev_err(bus->dev, "DPN_OffsetCtrl2 register write failed\n");
                return ret;
        }

        /* Program DPN_BlockCtrl3 register */
        ret = sdw_write(slave, addr2, t_params->blk_pkg_mode);
        if (ret < 0) {
                dev_err(bus->dev, "DPN_BlockCtrl3 register write failed\n");
                return ret;
        }

        /*
         * Data ports are FULL, SIMPLE and REDUCED. This function handles
         * FULL and REDUCED only and beyond this point only FULL is
         * handled, so bail out if we are not FULL data port type
         */
        if (type != SDW_DPN_FULL)
                return ret;

        /* Program DPN_SampleCtrl2 register */
        wbuf = FIELD_GET(SDW_DPN_SAMPLECTRL_HIGH, t_params->sample_interval - 1);

        ret = sdw_write(slave, addr3, wbuf);
        if (ret < 0) {
                dev_err(bus->dev, "DPN_SampleCtrl2 register write failed\n");
                return ret;
        }

        /* Program DPN_HCtrl register */
        wbuf = FIELD_PREP(SDW_DPN_HCTRL_HSTART, t_params->hstart);
        wbuf |= FIELD_PREP(SDW_DPN_HCTRL_HSTOP, t_params->hstop);

        ret = sdw_write(slave, addr4, wbuf);
        if (ret < 0)
                dev_err(bus->dev, "DPN_HCtrl register write failed\n");

        return ret;
}

static int sdw_program_slave_port_params(struct sdw_bus *bus,
                                         struct sdw_slave_runtime *s_rt,
                                         struct sdw_port_runtime *p_rt)
{
        struct sdw_transport_params *t_params = &p_rt->transport_params;
        struct sdw_port_params *p_params = &p_rt->port_params;
        struct sdw_slave_prop *slave_prop = &s_rt->slave->prop;
        u32 addr1, addr2, addr3, addr4, addr5, addr6;
        struct sdw_dpn_prop *dpn_prop;
        int ret;
        u8 wbuf;

        if (s_rt->slave->is_mockup_device)
                return 0;

        dpn_prop = sdw_get_slave_dpn_prop(s_rt->slave,
                                          s_rt->direction,
                                          t_params->port_num);
        if (!dpn_prop)
                return -EINVAL;

        addr1 = SDW_DPN_PORTCTRL(t_params->port_num);
        addr2 = SDW_DPN_BLOCKCTRL1(t_params->port_num);

        if (bus->params.next_bank) {
                addr3 = SDW_DPN_SAMPLECTRL1_B1(t_params->port_num);
                addr4 = SDW_DPN_OFFSETCTRL1_B1(t_params->port_num);
                addr5 = SDW_DPN_BLOCKCTRL2_B1(t_params->port_num);
                addr6 = SDW_DPN_LANECTRL_B1(t_params->port_num);

        } else {
                addr3 = SDW_DPN_SAMPLECTRL1_B0(t_params->port_num);
                addr4 = SDW_DPN_OFFSETCTRL1_B0(t_params->port_num);
                addr5 = SDW_DPN_BLOCKCTRL2_B0(t_params->port_num);
                addr6 = SDW_DPN_LANECTRL_B0(t_params->port_num);
        }

        /* Program DPN_PortCtrl register */
        wbuf = FIELD_PREP(SDW_DPN_PORTCTRL_DATAMODE, p_params->data_mode);
        wbuf |= FIELD_PREP(SDW_DPN_PORTCTRL_FLOWMODE, p_params->flow_mode);

        ret = sdw_update(s_rt->slave, addr1, 0xF, wbuf);
        if (ret < 0) {
                dev_err(&s_rt->slave->dev,
                        "DPN_PortCtrl register write failed for port %d\n",
                        t_params->port_num);
                return ret;
        }

        if (!dpn_prop->read_only_wordlength) {
                /* Program DPN_BlockCtrl1 register */
                ret = sdw_write(s_rt->slave, addr2, (p_params->bps - 1));
                if (ret < 0) {
                        dev_err(&s_rt->slave->dev,
                                "DPN_BlockCtrl1 register write failed for port %d\n",
                                t_params->port_num);
                        return ret;
                }
        }

        /* Program DPN_SampleCtrl1 register */
        wbuf = (t_params->sample_interval - 1) & SDW_DPN_SAMPLECTRL_LOW;
        ret = sdw_write(s_rt->slave, addr3, wbuf);
        if (ret < 0) {
                dev_err(&s_rt->slave->dev,
                        "DPN_SampleCtrl1 register write failed for port %d\n",
                        t_params->port_num);
                return ret;
        }

        /* Program DPN_OffsetCtrl1 registers */
        ret = sdw_write(s_rt->slave, addr4, t_params->offset1);
        if (ret < 0) {
                dev_err(&s_rt->slave->dev,
                        "DPN_OffsetCtrl1 register write failed for port %d\n",
                        t_params->port_num);
                return ret;
        }

        /* Program DPN_BlockCtrl2 register*/
        if (t_params->blk_grp_ctrl_valid) {
                ret = sdw_write(s_rt->slave, addr5, t_params->blk_grp_ctrl);
                if (ret < 0) {
                        dev_err(&s_rt->slave->dev,
                                "DPN_BlockCtrl2 reg write failed for port %d\n",
                                t_params->port_num);
                        return ret;
                }
        }

        /* program DPN_LaneCtrl register */
        if (slave_prop->lane_control_support) {
                ret = sdw_write(s_rt->slave, addr6, t_params->lane_ctrl);
                if (ret < 0) {
                        dev_err(&s_rt->slave->dev,
                                "DPN_LaneCtrl register write failed for port %d\n",
                                t_params->port_num);
                        return ret;
                }
        }

        if (dpn_prop->type != SDW_DPN_SIMPLE) {
                ret = _sdw_program_slave_port_params(bus, s_rt->slave,
                                                     t_params, dpn_prop->type);
                if (ret < 0)
                        dev_err(&s_rt->slave->dev,
                                "Transport reg write failed for port: %d\n",
                                t_params->port_num);
        }

        return ret;
}

static int sdw_program_master_port_params(struct sdw_bus *bus,
                                          struct sdw_port_runtime *p_rt)
{
        int ret;

        /*
         * we need to set transport and port parameters for the port.
         * Transport parameters refers to the sample interval, offsets and
         * hstart/stop etc of the data. Port parameters refers to word
         * length, flow mode etc of the port
         */
        ret = bus->port_ops->dpn_set_port_transport_params(bus,
                                        &p_rt->transport_params,
                                        bus->params.next_bank);
        if (ret < 0)
                return ret;

        return bus->port_ops->dpn_set_port_params(bus,
                                                  &p_rt->port_params,
                                                  bus->params.next_bank);
}

/**
 * sdw_program_port_params() - Programs transport parameters of Master(s)
 * and Slave(s)
 *
 * @m_rt: Master stream runtime
 */
static int sdw_program_port_params(struct sdw_master_runtime *m_rt)
{
        struct sdw_slave_runtime *s_rt;
        struct sdw_bus *bus = m_rt->bus;
        struct sdw_port_runtime *p_rt;
        int ret = 0;

        /* Program transport & port parameters for Slave(s) */
        list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                list_for_each_entry(p_rt, &s_rt->port_list, port_node) {
                        ret = sdw_program_slave_port_params(bus, s_rt, p_rt);
                        if (ret < 0)
                                return ret;
                }
        }

        /* Program transport & port parameters for Master(s) */
        list_for_each_entry(p_rt, &m_rt->port_list, port_node) {
                ret = sdw_program_master_port_params(bus, p_rt);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

/**
 * sdw_enable_disable_slave_ports: Enable/disable slave data port
 *
 * @bus: bus instance
 * @s_rt: slave runtime
 * @p_rt: port runtime
 * @en: enable or disable operation
 *
 * This function only sets the enable/disable bits in the relevant bank, the
 * actual enable/disable is done with a bank switch
 */
static int sdw_enable_disable_slave_ports(struct sdw_bus *bus,
                                          struct sdw_slave_runtime *s_rt,
                                          struct sdw_port_runtime *p_rt,
                                          bool en)
{
        struct sdw_transport_params *t_params = &p_rt->transport_params;
        u32 addr;
        int ret;

        if (bus->params.next_bank)
                addr = SDW_DPN_CHANNELEN_B1(p_rt->num);
        else
                addr = SDW_DPN_CHANNELEN_B0(p_rt->num);

        /*
         * Since bus doesn't support sharing a port across two streams,
         * it is safe to reset this register
         */
        if (en)
                ret = sdw_write(s_rt->slave, addr, p_rt->ch_mask);
        else
                ret = sdw_write(s_rt->slave, addr, 0x0);

        if (ret < 0)
                dev_err(&s_rt->slave->dev,
                        "Slave chn_en reg write failed:%d port:%d\n",
                        ret, t_params->port_num);

        return ret;
}

static int sdw_enable_disable_master_ports(struct sdw_master_runtime *m_rt,
                                           struct sdw_port_runtime *p_rt,
                                           bool en)
{
        struct sdw_transport_params *t_params = &p_rt->transport_params;
        struct sdw_bus *bus = m_rt->bus;
        struct sdw_enable_ch enable_ch;
        int ret;

        enable_ch.port_num = p_rt->num;
        enable_ch.ch_mask = p_rt->ch_mask;
        enable_ch.enable = en;

        /* Perform Master port channel(s) enable/disable */
        if (bus->port_ops->dpn_port_enable_ch) {
                ret = bus->port_ops->dpn_port_enable_ch(bus,
                                                        &enable_ch,
                                                        bus->params.next_bank);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "Master chn_en write failed:%d port:%d\n",
                                ret, t_params->port_num);
                        return ret;
                }
        } else {
                dev_err(bus->dev,
                        "dpn_port_enable_ch not supported, %s failed\n",
                        en ? "enable" : "disable");
                return -EINVAL;
        }

        return 0;
}

/**
 * sdw_enable_disable_ports() - Enable/disable port(s) for Master and
 * Slave(s)
 *
 * @m_rt: Master stream runtime
 * @en: mode (enable/disable)
 */
static int sdw_enable_disable_ports(struct sdw_master_runtime *m_rt, bool en)
{
        struct sdw_port_runtime *s_port, *m_port;
        struct sdw_slave_runtime *s_rt;
        int ret = 0;

        /* Enable/Disable Slave port(s) */
        list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                list_for_each_entry(s_port, &s_rt->port_list, port_node) {
                        ret = sdw_enable_disable_slave_ports(m_rt->bus, s_rt,
                                                             s_port, en);
                        if (ret < 0)
                                return ret;
                }
        }

        /* Enable/Disable Master port(s) */
        list_for_each_entry(m_port, &m_rt->port_list, port_node) {
                ret = sdw_enable_disable_master_ports(m_rt, m_port, en);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int sdw_do_port_prep(struct sdw_slave_runtime *s_rt,
                            struct sdw_prepare_ch prep_ch,
                            enum sdw_port_prep_ops cmd)
{
        const struct sdw_slave_ops *ops = s_rt->slave->ops;
        int ret;

        if (ops->port_prep) {
                ret = ops->port_prep(s_rt->slave, &prep_ch, cmd);
                if (ret < 0) {
                        dev_err(&s_rt->slave->dev,
                                "Slave Port Prep cmd %d failed: %d\n",
                                cmd, ret);
                        return ret;
                }
        }

        return 0;
}

static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,
                                       struct sdw_slave_runtime *s_rt,
                                       struct sdw_port_runtime *p_rt,
                                       bool prep)
{
        struct completion *port_ready;
        struct sdw_dpn_prop *dpn_prop;
        struct sdw_prepare_ch prep_ch;
        bool intr = false;
        int ret = 0, val;
        u32 addr;

        prep_ch.num = p_rt->num;
        prep_ch.ch_mask = p_rt->ch_mask;

        dpn_prop = sdw_get_slave_dpn_prop(s_rt->slave,
                                          s_rt->direction,
                                          prep_ch.num);
        if (!dpn_prop) {
                dev_err(bus->dev,
                        "Slave Port:%d properties not found\n", prep_ch.num);
                return -EINVAL;
        }

        prep_ch.prepare = prep;

        prep_ch.bank = bus->params.next_bank;

        if (dpn_prop->imp_def_interrupts || !dpn_prop->simple_ch_prep_sm ||
            bus->params.s_data_mode != SDW_PORT_DATA_MODE_NORMAL)
                intr = true;

        /*
         * Enable interrupt before Port prepare.
         * For Port de-prepare, it is assumed that port
         * was prepared earlier
         */
        if (prep && intr) {
                ret = sdw_configure_dpn_intr(s_rt->slave, p_rt->num, prep,
                                             dpn_prop->imp_def_interrupts);
                if (ret < 0)
                        return ret;
        }

        /* Inform slave about the impending port prepare */
        sdw_do_port_prep(s_rt, prep_ch, SDW_OPS_PORT_PRE_PREP);

        /* Prepare Slave port implementing CP_SM */
        if (!dpn_prop->simple_ch_prep_sm) {
                addr = SDW_DPN_PREPARECTRL(p_rt->num);

                if (prep)
                        ret = sdw_write(s_rt->slave, addr, p_rt->ch_mask);
                else
                        ret = sdw_write(s_rt->slave, addr, 0x0);

                if (ret < 0) {
                        dev_err(&s_rt->slave->dev,
                                "Slave prep_ctrl reg write failed\n");
                        return ret;
                }

                /* Wait for completion on port ready */
                port_ready = &s_rt->slave->port_ready[prep_ch.num];
                wait_for_completion_timeout(port_ready,
                        msecs_to_jiffies(dpn_prop->ch_prep_timeout));

                val = sdw_read(s_rt->slave, SDW_DPN_PREPARESTATUS(p_rt->num));
                if ((val < 0) || (val & p_rt->ch_mask)) {
                        ret = (val < 0) ? val : -ETIMEDOUT;
                        dev_err(&s_rt->slave->dev,
                                "Chn prep failed for port %d: %d\n", prep_ch.num, ret);
                        return ret;
                }
        }

        /* Inform slaves about ports prepared */
        sdw_do_port_prep(s_rt, prep_ch, SDW_OPS_PORT_POST_PREP);

        /* Disable interrupt after Port de-prepare */
        if (!prep && intr)
                ret = sdw_configure_dpn_intr(s_rt->slave, p_rt->num, prep,
                                             dpn_prop->imp_def_interrupts);

        return ret;
}

static int sdw_prep_deprep_master_ports(struct sdw_master_runtime *m_rt,
                                        struct sdw_port_runtime *p_rt,
                                        bool prep)
{
        struct sdw_transport_params *t_params = &p_rt->transport_params;
        struct sdw_bus *bus = m_rt->bus;
        const struct sdw_master_port_ops *ops = bus->port_ops;
        struct sdw_prepare_ch prep_ch;
        int ret = 0;

        prep_ch.num = p_rt->num;
        prep_ch.ch_mask = p_rt->ch_mask;
        prep_ch.prepare = prep; /* Prepare/De-prepare */
        prep_ch.bank = bus->params.next_bank;

        /* Pre-prepare/Pre-deprepare port(s) */
        if (ops->dpn_port_prep) {
                ret = ops->dpn_port_prep(bus, &prep_ch);
                if (ret < 0) {
                        dev_err(bus->dev, "Port prepare failed for port:%d\n",
                                t_params->port_num);
                        return ret;
                }
        }

        return ret;
}

/**
 * sdw_prep_deprep_ports() - Prepare/De-prepare port(s) for Master(s) and
 * Slave(s)
 *
 * @m_rt: Master runtime handle
 * @prep: Prepare or De-prepare
 */
static int sdw_prep_deprep_ports(struct sdw_master_runtime *m_rt, bool prep)
{
        struct sdw_slave_runtime *s_rt;
        struct sdw_port_runtime *p_rt;
        int ret = 0;

        /* Prepare/De-prepare Slave port(s) */
        list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                list_for_each_entry(p_rt, &s_rt->port_list, port_node) {
                        ret = sdw_prep_deprep_slave_ports(m_rt->bus, s_rt,
                                                          p_rt, prep);
                        if (ret < 0)
                                return ret;
                }
        }

        /* Prepare/De-prepare Master port(s) */
        list_for_each_entry(p_rt, &m_rt->port_list, port_node) {
                ret = sdw_prep_deprep_master_ports(m_rt, p_rt, prep);
                if (ret < 0)
                        return ret;
        }

        return ret;
}

/**
 * sdw_notify_config() - Notify bus configuration
 *
 * @m_rt: Master runtime handle
 *
 * This function notifies the Master(s) and Slave(s) of the
 * new bus configuration.
 */
static int sdw_notify_config(struct sdw_master_runtime *m_rt)
{
        struct sdw_slave_runtime *s_rt;
        struct sdw_bus *bus = m_rt->bus;
        struct sdw_slave *slave;
        int ret = 0;

        if (bus->ops->set_bus_conf) {
                ret = bus->ops->set_bus_conf(bus, &bus->params);
                if (ret < 0)
                        return ret;
        }

        list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                slave = s_rt->slave;

                if (slave->ops->bus_config) {
                        ret = slave->ops->bus_config(slave, &bus->params);
                        if (ret < 0) {
                                dev_err(bus->dev, "Notify Slave: %d failed\n",
                                        slave->dev_num);
                                return ret;
                        }
                }
        }

        return ret;
}

/**
 * sdw_program_params() - Program transport and port parameters for Master(s)
 * and Slave(s)
 *
 * @bus: SDW bus instance
 * @prepare: true if sdw_program_params() is called by _prepare.
 */
static int sdw_program_params(struct sdw_bus *bus, bool prepare)
{
        struct sdw_master_runtime *m_rt;
        int ret = 0;

        list_for_each_entry(m_rt, &bus->m_rt_list, bus_node) {

                /*
                 * this loop walks through all master runtimes for a
                 * bus, but the ports can only be configured while
                 * explicitly preparing a stream or handling an
                 * already-prepared stream otherwise.
                 */
                if (!prepare &&
                    m_rt->stream->state == SDW_STREAM_CONFIGURED)
                        continue;

                ret = sdw_program_port_params(m_rt);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "Program transport params failed: %d\n", ret);
                        return ret;
                }

                ret = sdw_notify_config(m_rt);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "Notify bus config failed: %d\n", ret);
                        return ret;
                }

                /* Enable port(s) on alternate bank for all active streams */
                if (m_rt->stream->state != SDW_STREAM_ENABLED)
                        continue;

                ret = sdw_enable_disable_ports(m_rt, true);
                if (ret < 0) {
                        dev_err(bus->dev, "Enable channel failed: %d\n", ret);
                        return ret;
                }
        }

        return ret;
}

static int sdw_bank_switch(struct sdw_bus *bus, int m_rt_count)
{
        int col_index, row_index;
        bool multi_link;
        struct sdw_msg *wr_msg;
        u8 *wbuf;
        int ret;
        u16 addr;

        wr_msg = kzalloc(sizeof(*wr_msg), GFP_KERNEL);
        if (!wr_msg)
                return -ENOMEM;

        bus->defer_msg.msg = wr_msg;

        wbuf = kzalloc(sizeof(*wbuf), GFP_KERNEL);
        if (!wbuf) {
                ret = -ENOMEM;
                goto error_1;
        }

        /* Get row and column index to program register */
        col_index = sdw_find_col_index(bus->params.col);
        row_index = sdw_find_row_index(bus->params.row);
        wbuf[0] = col_index | (row_index << 3);

        if (bus->params.next_bank)
                addr = SDW_SCP_FRAMECTRL_B1;
        else
                addr = SDW_SCP_FRAMECTRL_B0;

        sdw_fill_msg(wr_msg, NULL, addr, 1, SDW_BROADCAST_DEV_NUM,
                     SDW_MSG_FLAG_WRITE, wbuf);
        wr_msg->ssp_sync = true;

        /*
         * Set the multi_link flag only when both the hardware supports
         * and hardware-based sync is required
         */
        multi_link = bus->multi_link && (m_rt_count >= bus->hw_sync_min_links);

        if (multi_link)
                ret = sdw_transfer_defer(bus, wr_msg, &bus->defer_msg);
        else
                ret = sdw_transfer(bus, wr_msg);

        if (ret < 0 && ret != -ENODATA) {
                dev_err(bus->dev, "Slave frame_ctrl reg write failed\n");
                goto error;
        }

        if (!multi_link) {
                kfree(wr_msg);
                kfree(wbuf);
                bus->defer_msg.msg = NULL;
                bus->params.curr_bank = !bus->params.curr_bank;
                bus->params.next_bank = !bus->params.next_bank;
        }

        return 0;

error:
        kfree(wbuf);
error_1:
        kfree(wr_msg);
        bus->defer_msg.msg = NULL;
        return ret;
}

/**
 * sdw_ml_sync_bank_switch: Multilink register bank switch
 *
 * @bus: SDW bus instance
 *
 * Caller function should free the buffers on error
 */
static int sdw_ml_sync_bank_switch(struct sdw_bus *bus)
{
        unsigned long time_left;

        if (!bus->multi_link)
                return 0;

        /* Wait for completion of transfer */
        time_left = wait_for_completion_timeout(&bus->defer_msg.complete,
                                                bus->bank_switch_timeout);

        if (!time_left) {
                dev_err(bus->dev, "Controller Timed out on bank switch\n");
                return -ETIMEDOUT;
        }

        bus->params.curr_bank = !bus->params.curr_bank;
        bus->params.next_bank = !bus->params.next_bank;

        if (bus->defer_msg.msg) {
                kfree(bus->defer_msg.msg->buf);
                kfree(bus->defer_msg.msg);
        }

        return 0;
}

static int do_bank_switch(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        const struct sdw_master_ops *ops;
        struct sdw_bus *bus;
        bool multi_link = false;
        int m_rt_count;
        int ret = 0;

        m_rt_count = stream->m_rt_count;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                ops = bus->ops;

                if (bus->multi_link && m_rt_count >= bus->hw_sync_min_links) {
                        multi_link = true;
                        mutex_lock(&bus->msg_lock);
                }

                /* Pre-bank switch */
                if (ops->pre_bank_switch) {
                        ret = ops->pre_bank_switch(bus);
                        if (ret < 0) {
                                dev_err(bus->dev,
                                        "Pre bank switch op failed: %d\n", ret);
                                goto msg_unlock;
                        }
                }

                /*
                 * Perform Bank switch operation.
                 * For multi link cases, the actual bank switch is
                 * synchronized across all Masters and happens later as a
                 * part of post_bank_switch ops.
                 */
                ret = sdw_bank_switch(bus, m_rt_count);
                if (ret < 0) {
                        dev_err(bus->dev, "Bank switch failed: %d\n", ret);
                        goto error;
                }
        }

        /*
         * For multi link cases, it is expected that the bank switch is
         * triggered by the post_bank_switch for the first Master in the list
         * and for the other Masters the post_bank_switch() should return doing
         * nothing.
         */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                ops = bus->ops;

                /* Post-bank switch */
                if (ops->post_bank_switch) {
                        ret = ops->post_bank_switch(bus);
                        if (ret < 0) {
                                dev_err(bus->dev,
                                        "Post bank switch op failed: %d\n",
                                        ret);
                                goto error;
                        }
                } else if (multi_link) {
                        dev_err(bus->dev,
                                "Post bank switch ops not implemented\n");
                        goto error;
                }

                /* Set the bank switch timeout to default, if not set */
                if (!bus->bank_switch_timeout)
                        bus->bank_switch_timeout = DEFAULT_BANK_SWITCH_TIMEOUT;

                /* Check if bank switch was successful */
                ret = sdw_ml_sync_bank_switch(bus);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "multi link bank switch failed: %d\n", ret);
                        goto error;
                }

                if (multi_link)
                        mutex_unlock(&bus->msg_lock);
        }

        return ret;

error:
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                if (bus->defer_msg.msg) {
                        kfree(bus->defer_msg.msg->buf);
                        kfree(bus->defer_msg.msg);
                }
        }

msg_unlock:

        if (multi_link) {
                list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                        bus = m_rt->bus;
                        if (mutex_is_locked(&bus->msg_lock))
                                mutex_unlock(&bus->msg_lock);
                }
        }

        return ret;
}

/**
 * sdw_release_stream() - Free the assigned stream runtime
 *
 * @stream: SoundWire stream runtime
 *
 * sdw_release_stream should be called only once per stream
 */
void sdw_release_stream(struct sdw_stream_runtime *stream)
{
        kfree(stream);
}
EXPORT_SYMBOL(sdw_release_stream);

/**
 * sdw_alloc_stream() - Allocate and return stream runtime
 *
 * @stream_name: SoundWire stream name
 *
 * Allocates a SoundWire stream runtime instance.
 * sdw_alloc_stream should be called only once per stream. Typically
 * invoked from ALSA/ASoC machine/platform driver.
 */
struct sdw_stream_runtime *sdw_alloc_stream(const char *stream_name)
{
        struct sdw_stream_runtime *stream;

        stream = kzalloc(sizeof(*stream), GFP_KERNEL);
        if (!stream)
                return NULL;

        stream->name = stream_name;
        INIT_LIST_HEAD(&stream->master_list);
        stream->state = SDW_STREAM_ALLOCATED;
        stream->m_rt_count = 0;

        return stream;
}
EXPORT_SYMBOL(sdw_alloc_stream);

static struct sdw_master_runtime
*sdw_find_master_rt(struct sdw_bus *bus,
                    struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;

        /* Retrieve Bus handle if already available */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                if (m_rt->bus == bus)
                        return m_rt;
        }

        return NULL;
}

/**
 * sdw_alloc_master_rt() - Allocates and initialize Master runtime handle
 *
 * @bus: SDW bus instance
 * @stream_config: Stream configuration
 * @stream: Stream runtime handle.
 *
 * This function is to be called with bus_lock held.
 */
static struct sdw_master_runtime
*sdw_alloc_master_rt(struct sdw_bus *bus,
                     struct sdw_stream_config *stream_config,
                     struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;

        /*
         * check if Master is already allocated (as a result of Slave adding
         * it first), if so skip allocation and go to configure
         */
        m_rt = sdw_find_master_rt(bus, stream);
        if (m_rt)
                goto stream_config;

        m_rt = kzalloc(sizeof(*m_rt), GFP_KERNEL);
        if (!m_rt)
                return NULL;

        /* Initialization of Master runtime handle */
        INIT_LIST_HEAD(&m_rt->port_list);
        INIT_LIST_HEAD(&m_rt->slave_rt_list);
        list_add_tail(&m_rt->stream_node, &stream->master_list);

        list_add_tail(&m_rt->bus_node, &bus->m_rt_list);

stream_config:
        m_rt->ch_count = stream_config->ch_count;
        m_rt->bus = bus;
        m_rt->stream = stream;
        m_rt->direction = stream_config->direction;

        return m_rt;
}

/**
 * sdw_alloc_slave_rt() - Allocate and initialize Slave runtime handle.
 *
 * @slave: Slave handle
 * @stream_config: Stream configuration
 * @stream: Stream runtime handle
 *
 * This function is to be called with bus_lock held.
 */
static struct sdw_slave_runtime
*sdw_alloc_slave_rt(struct sdw_slave *slave,
                    struct sdw_stream_config *stream_config,
                    struct sdw_stream_runtime *stream)
{
        struct sdw_slave_runtime *s_rt;

        s_rt = kzalloc(sizeof(*s_rt), GFP_KERNEL);
        if (!s_rt)
                return NULL;

        INIT_LIST_HEAD(&s_rt->port_list);
        s_rt->ch_count = stream_config->ch_count;
        s_rt->direction = stream_config->direction;
        s_rt->slave = slave;

        return s_rt;
}

static void sdw_master_port_release(struct sdw_bus *bus,
                                    struct sdw_master_runtime *m_rt)
{
        struct sdw_port_runtime *p_rt, *_p_rt;

        list_for_each_entry_safe(p_rt, _p_rt, &m_rt->port_list, port_node) {
                list_del(&p_rt->port_node);
                kfree(p_rt);
        }
}

static void sdw_slave_port_release(struct sdw_bus *bus,
                                   struct sdw_slave *slave,
                                   struct sdw_stream_runtime *stream)
{
        struct sdw_port_runtime *p_rt, *_p_rt;
        struct sdw_master_runtime *m_rt;
        struct sdw_slave_runtime *s_rt;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                list_for_each_entry(s_rt, &m_rt->slave_rt_list, m_rt_node) {
                        if (s_rt->slave != slave)
                                continue;

                        list_for_each_entry_safe(p_rt, _p_rt,
                                                 &s_rt->port_list, port_node) {
                                list_del(&p_rt->port_node);
                                kfree(p_rt);
                        }
                }
        }
}

/**
 * sdw_release_slave_stream() - Free Slave(s) runtime handle
 *
 * @slave: Slave handle.
 * @stream: Stream runtime handle.
 *
 * This function is to be called with bus_lock held.
 */
static void sdw_release_slave_stream(struct sdw_slave *slave,
                                     struct sdw_stream_runtime *stream)
{
        struct sdw_slave_runtime *s_rt, *_s_rt;
        struct sdw_master_runtime *m_rt;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                /* Retrieve Slave runtime handle */
                list_for_each_entry_safe(s_rt, _s_rt,
                                         &m_rt->slave_rt_list, m_rt_node) {
                        if (s_rt->slave == slave) {
                                list_del(&s_rt->m_rt_node);
                                kfree(s_rt);
                                return;
                        }
                }
        }
}

/**
 * sdw_release_master_stream() - Free Master runtime handle
 *
 * @m_rt: Master runtime node
 * @stream: Stream runtime handle.
 *
 * This function is to be called with bus_lock held
 * It frees the Master runtime handle and associated Slave(s) runtime
 * handle. If this is called first then sdw_release_slave_stream() will have
 * no effect as Slave(s) runtime handle would already be freed up.
 */
static void sdw_release_master_stream(struct sdw_master_runtime *m_rt,
                                      struct sdw_stream_runtime *stream)
{
        struct sdw_slave_runtime *s_rt, *_s_rt;

        list_for_each_entry_safe(s_rt, _s_rt, &m_rt->slave_rt_list, m_rt_node) {
                sdw_slave_port_release(s_rt->slave->bus, s_rt->slave, stream);
                sdw_release_slave_stream(s_rt->slave, stream);
        }

        list_del(&m_rt->stream_node);
        list_del(&m_rt->bus_node);
        kfree(m_rt);
}

/**
 * sdw_stream_remove_master() - Remove master from sdw_stream
 *
 * @bus: SDW Bus instance
 * @stream: SoundWire stream
 *
 * This removes and frees port_rt and master_rt from a stream
 */
int sdw_stream_remove_master(struct sdw_bus *bus,
                             struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt, *_m_rt;

        mutex_lock(&bus->bus_lock);

        list_for_each_entry_safe(m_rt, _m_rt,
                                 &stream->master_list, stream_node) {
                if (m_rt->bus != bus)
                        continue;

                sdw_master_port_release(bus, m_rt);
                sdw_release_master_stream(m_rt, stream);
                stream->m_rt_count--;
        }

        if (list_empty(&stream->master_list))
                stream->state = SDW_STREAM_RELEASED;

        mutex_unlock(&bus->bus_lock);

        return 0;
}
EXPORT_SYMBOL(sdw_stream_remove_master);

/**
 * sdw_stream_remove_slave() - Remove slave from sdw_stream
 *
 * @slave: SDW Slave instance
 * @stream: SoundWire stream
 *
 * This removes and frees port_rt and slave_rt from a stream
 */
int sdw_stream_remove_slave(struct sdw_slave *slave,
                            struct sdw_stream_runtime *stream)
{
        mutex_lock(&slave->bus->bus_lock);

        sdw_slave_port_release(slave->bus, slave, stream);
        sdw_release_slave_stream(slave, stream);

        mutex_unlock(&slave->bus->bus_lock);

        return 0;
}
EXPORT_SYMBOL(sdw_stream_remove_slave);

/**
 * sdw_config_stream() - Configure the allocated stream
 *
 * @dev: SDW device
 * @stream: SoundWire stream
 * @stream_config: Stream configuration for audio stream
 * @is_slave: is API called from Slave or Master
 *
 * This function is to be called with bus_lock held.
 */
static int sdw_config_stream(struct device *dev,
                             struct sdw_stream_runtime *stream,
                             struct sdw_stream_config *stream_config,
                             bool is_slave)
{
        /*
         * Update the stream rate, channel and bps based on data
         * source. For more than one data source (multilink),
         * match the rate, bps, stream type and increment number of channels.
         *
         * If rate/bps is zero, it means the values are not set, so skip
         * comparison and allow the value to be set and stored in stream
         */
        if (stream->params.rate &&
            stream->params.rate != stream_config->frame_rate) {
                dev_err(dev, "rate not matching, stream:%s\n", stream->name);
                return -EINVAL;
        }

        if (stream->params.bps &&
            stream->params.bps != stream_config->bps) {
                dev_err(dev, "bps not matching, stream:%s\n", stream->name);
                return -EINVAL;
        }

        stream->type = stream_config->type;
        stream->params.rate = stream_config->frame_rate;
        stream->params.bps = stream_config->bps;

        /* TODO: Update this check during Device-device support */
        if (is_slave)
                stream->params.ch_count += stream_config->ch_count;

        return 0;
}

static int sdw_is_valid_port_range(struct device *dev,
                                   struct sdw_port_runtime *p_rt)
{
        if (!SDW_VALID_PORT_RANGE(p_rt->num)) {
                dev_err(dev,
                        "SoundWire: Invalid port number :%d\n", p_rt->num);
                return -EINVAL;
        }

        return 0;
}

static struct sdw_port_runtime
*sdw_port_alloc(struct device *dev,
                struct sdw_port_config *port_config,
                int port_index)
{
        struct sdw_port_runtime *p_rt;

        p_rt = kzalloc(sizeof(*p_rt), GFP_KERNEL);
        if (!p_rt)
                return NULL;

        p_rt->ch_mask = port_config[port_index].ch_mask;
        p_rt->num = port_config[port_index].num;

        return p_rt;
}

static int sdw_master_port_config(struct sdw_bus *bus,
                                  struct sdw_master_runtime *m_rt,
                                  struct sdw_port_config *port_config,
                                  unsigned int num_ports)
{
        struct sdw_port_runtime *p_rt;
        int i;

        /* Iterate for number of ports to perform initialization */
        for (i = 0; i < num_ports; i++) {
                p_rt = sdw_port_alloc(bus->dev, port_config, i);
                if (!p_rt)
                        return -ENOMEM;

                /*
                 * TODO: Check port capabilities for requested
                 * configuration (audio mode support)
                 */

                list_add_tail(&p_rt->port_node, &m_rt->port_list);
        }

        return 0;
}

static int sdw_slave_port_config(struct sdw_slave *slave,
                                 struct sdw_slave_runtime *s_rt,
                                 struct sdw_port_config *port_config,
                                 unsigned int num_config)
{
        struct sdw_port_runtime *p_rt;
        int i, ret;

        /* Iterate for number of ports to perform initialization */
        for (i = 0; i < num_config; i++) {
                p_rt = sdw_port_alloc(&slave->dev, port_config, i);
                if (!p_rt)
                        return -ENOMEM;

                /*
                 * TODO: Check valid port range as defined by DisCo/
                 * slave
                 */
                ret = sdw_is_valid_port_range(&slave->dev, p_rt);
                if (ret < 0) {
                        kfree(p_rt);
                        return ret;
                }

                /*
                 * TODO: Check port capabilities for requested
                 * configuration (audio mode support)
                 */

                list_add_tail(&p_rt->port_node, &s_rt->port_list);
        }

        return 0;
}

/**
 * sdw_stream_add_master() - Allocate and add master runtime to a stream
 *
 * @bus: SDW Bus instance
 * @stream_config: Stream configuration for audio stream
 * @port_config: Port configuration for audio stream
 * @num_ports: Number of ports
 * @stream: SoundWire stream
 */
int sdw_stream_add_master(struct sdw_bus *bus,
                          struct sdw_stream_config *stream_config,
                          struct sdw_port_config *port_config,
                          unsigned int num_ports,
                          struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        int ret;

        mutex_lock(&bus->bus_lock);

        /*
         * For multi link streams, add the second master only if
         * the bus supports it.
         * Check if bus->multi_link is set
         */
        if (!bus->multi_link && stream->m_rt_count > 0) {
                dev_err(bus->dev,
                        "Multilink not supported, link %d\n", bus->link_id);
                ret = -EINVAL;
                goto unlock;
        }

        m_rt = sdw_alloc_master_rt(bus, stream_config, stream);
        if (!m_rt) {
                dev_err(bus->dev,
                        "Master runtime config failed for stream:%s\n",
                        stream->name);
                ret = -ENOMEM;
                goto unlock;
        }

        ret = sdw_config_stream(bus->dev, stream, stream_config, false);
        if (ret)
                goto stream_error;

        ret = sdw_master_port_config(bus, m_rt, port_config, num_ports);
        if (ret)
                goto stream_error;

        stream->m_rt_count++;

        goto unlock;

stream_error:
        sdw_release_master_stream(m_rt, stream);
unlock:
        mutex_unlock(&bus->bus_lock);
        return ret;
}
EXPORT_SYMBOL(sdw_stream_add_master);

/**
 * sdw_stream_add_slave() - Allocate and add master/slave runtime to a stream
 *
 * @slave: SDW Slave instance
 * @stream_config: Stream configuration for audio stream
 * @stream: SoundWire stream
 * @port_config: Port configuration for audio stream
 * @num_ports: Number of ports
 *
 * It is expected that Slave is added before adding Master
 * to the Stream.
 *
 */
int sdw_stream_add_slave(struct sdw_slave *slave,
                         struct sdw_stream_config *stream_config,
                         struct sdw_port_config *port_config,
                         unsigned int num_ports,
                         struct sdw_stream_runtime *stream)
{
        struct sdw_slave_runtime *s_rt;
        struct sdw_master_runtime *m_rt;
        int ret;

        mutex_lock(&slave->bus->bus_lock);

        /*
         * If this API is invoked by Slave first then m_rt is not valid.
         * So, allocate m_rt and add Slave to it.
         */
        m_rt = sdw_alloc_master_rt(slave->bus, stream_config, stream);
        if (!m_rt) {
                dev_err(&slave->dev,
                        "alloc master runtime failed for stream:%s\n",
                        stream->name);
                ret = -ENOMEM;
                goto error;
        }

        s_rt = sdw_alloc_slave_rt(slave, stream_config, stream);
        if (!s_rt) {
                dev_err(&slave->dev,
                        "Slave runtime config failed for stream:%s\n",
                        stream->name);
                ret = -ENOMEM;
                goto stream_error;
        }

        ret = sdw_config_stream(&slave->dev, stream, stream_config, true);
        if (ret) {
                /*
                 * sdw_release_master_stream will release s_rt in slave_rt_list in
                 * stream_error case, but s_rt is only added to slave_rt_list
                 * when sdw_config_stream is successful, so free s_rt explicitly
                 * when sdw_config_stream is failed.
                 */
                kfree(s_rt);
                goto stream_error;
        }

        list_add_tail(&s_rt->m_rt_node, &m_rt->slave_rt_list);

        ret = sdw_slave_port_config(slave, s_rt, port_config, num_ports);
        if (ret)
                goto stream_error;

        /*
         * Change stream state to CONFIGURED on first Slave add.
         * Bus is not aware of number of Slave(s) in a stream at this
         * point so cannot depend on all Slave(s) to be added in order to
         * change stream state to CONFIGURED.
         */
        stream->state = SDW_STREAM_CONFIGURED;
        goto error;

stream_error:
        /*
         * we hit error so cleanup the stream, release all Slave(s) and
         * Master runtime
         */
        sdw_release_master_stream(m_rt, stream);
error:
        mutex_unlock(&slave->bus->bus_lock);
        return ret;
}
EXPORT_SYMBOL(sdw_stream_add_slave);

/**
 * sdw_get_slave_dpn_prop() - Get Slave port capabilities
 *
 * @slave: Slave handle
 * @direction: Data direction.
 * @port_num: Port number
 */
struct sdw_dpn_prop *sdw_get_slave_dpn_prop(struct sdw_slave *slave,
                                            enum sdw_data_direction direction,
                                            unsigned int port_num)
{
        struct sdw_dpn_prop *dpn_prop;
        u8 num_ports;
        int i;

        if (direction == SDW_DATA_DIR_TX) {
                num_ports = hweight32(slave->prop.source_ports);
                dpn_prop = slave->prop.src_dpn_prop;
        } else {
                num_ports = hweight32(slave->prop.sink_ports);
                dpn_prop = slave->prop.sink_dpn_prop;
        }

        for (i = 0; i < num_ports; i++) {
                if (dpn_prop[i].num == port_num)
                        return &dpn_prop[i];
        }

        return NULL;
}

/**
 * sdw_acquire_bus_lock: Acquire bus lock for all Master runtime(s)
 *
 * @stream: SoundWire stream
 *
 * Acquire bus_lock for each of the master runtime(m_rt) part of this
 * stream to reconfigure the bus.
 * NOTE: This function is called from SoundWire stream ops and is
 * expected that a global lock is held before acquiring bus_lock.
 */
static void sdw_acquire_bus_lock(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        struct sdw_bus *bus;

        /* Iterate for all Master(s) in Master list */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;

                mutex_lock(&bus->bus_lock);
        }
}

/**
 * sdw_release_bus_lock: Release bus lock for all Master runtime(s)
 *
 * @stream: SoundWire stream
 *
 * Release the previously held bus_lock after reconfiguring the bus.
 * NOTE: This function is called from SoundWire stream ops and is
 * expected that a global lock is held before releasing bus_lock.
 */
static void sdw_release_bus_lock(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        struct sdw_bus *bus;

        /* Iterate for all Master(s) in Master list */
        list_for_each_entry_reverse(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                mutex_unlock(&bus->bus_lock);
        }
}

static int _sdw_prepare_stream(struct sdw_stream_runtime *stream,
                               bool update_params)
{
        struct sdw_master_runtime *m_rt;
        struct sdw_bus *bus = NULL;
        struct sdw_master_prop *prop;
        struct sdw_bus_params params;
        int ret;

        /* Prepare  Master(s) and Slave(s) port(s) associated with stream */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                prop = &bus->prop;
                memcpy(&params, &bus->params, sizeof(params));

                /* TODO: Support Asynchronous mode */
                if ((prop->max_clk_freq % stream->params.rate) != 0) {
                        dev_err(bus->dev, "Async mode not supported\n");
                        return -EINVAL;
                }

                if (!update_params)
                        goto program_params;

                /* Increment cumulative bus bandwidth */
                /* TODO: Update this during Device-Device support */
                bus->params.bandwidth += m_rt->stream->params.rate *
                        m_rt->ch_count * m_rt->stream->params.bps;

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

program_params:
                /* Program params */
                ret = sdw_program_params(bus, true);
                if (ret < 0) {
                        dev_err(bus->dev, "Program params failed: %d\n", ret);
                        goto restore_params;
                }
        }

        if (!bus) {
                pr_err("Configuration error in %s\n", __func__);
                return -EINVAL;
        }

        ret = do_bank_switch(stream);
        if (ret < 0) {
                dev_err(bus->dev, "Bank switch failed: %d\n", ret);
                goto restore_params;
        }

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;

                /* Prepare port(s) on the new clock configuration */
                ret = sdw_prep_deprep_ports(m_rt, true);
                if (ret < 0) {
                        dev_err(bus->dev, "Prepare port(s) failed ret = %d\n",
                                ret);
                        return ret;
                }
        }

        stream->state = SDW_STREAM_PREPARED;

        return ret;

restore_params:
        memcpy(&bus->params, &params, sizeof(params));
        return ret;
}

/**
 * sdw_prepare_stream() - Prepare SoundWire stream
 *
 * @stream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
int sdw_prepare_stream(struct sdw_stream_runtime *stream)
{
        bool update_params = true;
        int ret;

        if (!stream) {
                pr_err("SoundWire: Handle not found for stream\n");
                return -EINVAL;
        }

        sdw_acquire_bus_lock(stream);

        if (stream->state == SDW_STREAM_PREPARED) {
                ret = 0;
                goto state_err;
        }

        if (stream->state != SDW_STREAM_CONFIGURED &&
            stream->state != SDW_STREAM_DEPREPARED &&
            stream->state != SDW_STREAM_DISABLED) {
                pr_err("%s: %s: inconsistent state state %d\n",
                       __func__, stream->name, stream->state);
                ret = -EINVAL;
                goto state_err;
        }

        /*
         * when the stream is DISABLED, this means sdw_prepare_stream()
         * is called as a result of an underflow or a resume operation.
         * In this case, the bus parameters shall not be recomputed, but
         * still need to be re-applied
         */
        if (stream->state == SDW_STREAM_DISABLED)
                update_params = false;

        ret = _sdw_prepare_stream(stream, update_params);

state_err:
        sdw_release_bus_lock(stream);
        return ret;
}
EXPORT_SYMBOL(sdw_prepare_stream);

static int _sdw_enable_stream(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        struct sdw_bus *bus = NULL;
        int ret;

        /* Enable Master(s) and Slave(s) port(s) associated with stream */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;

                /* Program params */
                ret = sdw_program_params(bus, false);
                if (ret < 0) {
                        dev_err(bus->dev, "Program params failed: %d\n", ret);
                        return ret;
                }

                /* Enable port(s) */
                ret = sdw_enable_disable_ports(m_rt, true);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "Enable port(s) failed ret: %d\n", ret);
                        return ret;
                }
        }

        if (!bus) {
                pr_err("Configuration error in %s\n", __func__);
                return -EINVAL;
        }

        ret = do_bank_switch(stream);
        if (ret < 0) {
                dev_err(bus->dev, "Bank switch failed: %d\n", ret);
                return ret;
        }

        stream->state = SDW_STREAM_ENABLED;
        return 0;
}

/**
 * sdw_enable_stream() - Enable SoundWire stream
 *
 * @stream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
int sdw_enable_stream(struct sdw_stream_runtime *stream)
{
        int ret;

        if (!stream) {
                pr_err("SoundWire: Handle not found for stream\n");
                return -EINVAL;
        }

        sdw_acquire_bus_lock(stream);

        if (stream->state != SDW_STREAM_PREPARED &&
            stream->state != SDW_STREAM_DISABLED) {
                pr_err("%s: %s: inconsistent state state %d\n",
                       __func__, stream->name, stream->state);
                ret = -EINVAL;
                goto state_err;
        }

        ret = _sdw_enable_stream(stream);

state_err:
        sdw_release_bus_lock(stream);
        return ret;
}
EXPORT_SYMBOL(sdw_enable_stream);

static int _sdw_disable_stream(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        int ret;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                struct sdw_bus *bus = m_rt->bus;

                /* Disable port(s) */
                ret = sdw_enable_disable_ports(m_rt, false);
                if (ret < 0) {
                        dev_err(bus->dev, "Disable port(s) failed: %d\n", ret);
                        return ret;
                }
        }
        stream->state = SDW_STREAM_DISABLED;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                struct sdw_bus *bus = m_rt->bus;

                /* Program params */
                ret = sdw_program_params(bus, false);
                if (ret < 0) {
                        dev_err(bus->dev, "Program params failed: %d\n", ret);
                        return ret;
                }
        }

        ret = do_bank_switch(stream);
        if (ret < 0) {
                pr_err("Bank switch failed: %d\n", ret);
                return ret;
        }

        /* make sure alternate bank (previous current) is also disabled */
        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                struct sdw_bus *bus = m_rt->bus;

                /* Disable port(s) */
                ret = sdw_enable_disable_ports(m_rt, false);
                if (ret < 0) {
                        dev_err(bus->dev, "Disable port(s) failed: %d\n", ret);
                        return ret;
                }
        }

        return 0;
}

/**
 * sdw_disable_stream() - Disable SoundWire stream
 *
 * @stream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
int sdw_disable_stream(struct sdw_stream_runtime *stream)
{
        int ret;

        if (!stream) {
                pr_err("SoundWire: Handle not found for stream\n");
                return -EINVAL;
        }

        sdw_acquire_bus_lock(stream);

        if (stream->state != SDW_STREAM_ENABLED) {
                pr_err("%s: %s: inconsistent state state %d\n",
                       __func__, stream->name, stream->state);
                ret = -EINVAL;
                goto state_err;
        }

        ret = _sdw_disable_stream(stream);

state_err:
        sdw_release_bus_lock(stream);
        return ret;
}
EXPORT_SYMBOL(sdw_disable_stream);

static int _sdw_deprepare_stream(struct sdw_stream_runtime *stream)
{
        struct sdw_master_runtime *m_rt;
        struct sdw_bus *bus;
        int ret = 0;

        list_for_each_entry(m_rt, &stream->master_list, stream_node) {
                bus = m_rt->bus;
                /* De-prepare port(s) */
                ret = sdw_prep_deprep_ports(m_rt, false);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "De-prepare port(s) failed: %d\n", ret);
                        return ret;
                }

                /* TODO: Update this during Device-Device support */
                bus->params.bandwidth -= m_rt->stream->params.rate *
                        m_rt->ch_count * m_rt->stream->params.bps;

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

                /* Program params */
                ret = sdw_program_params(bus, false);
                if (ret < 0) {
                        dev_err(bus->dev, "Program params failed: %d\n", ret);
                        return ret;
                }
        }

        stream->state = SDW_STREAM_DEPREPARED;
        return do_bank_switch(stream);
}

/**
 * sdw_deprepare_stream() - Deprepare SoundWire stream
 *
 * @stream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
int sdw_deprepare_stream(struct sdw_stream_runtime *stream)
{
        int ret;

        if (!stream) {
                pr_err("SoundWire: Handle not found for stream\n");
                return -EINVAL;
        }

        sdw_acquire_bus_lock(stream);

        if (stream->state != SDW_STREAM_PREPARED &&
            stream->state != SDW_STREAM_DISABLED) {
                pr_err("%s: %s: inconsistent state state %d\n",
                       __func__, stream->name, stream->state);
                ret = -EINVAL;
                goto state_err;
        }

        ret = _sdw_deprepare_stream(stream);

state_err:
        sdw_release_bus_lock(stream);
        return ret;
}
EXPORT_SYMBOL(sdw_deprepare_stream);

static int set_stream(struct snd_pcm_substream *substream,
                      struct sdw_stream_runtime *sdw_stream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct snd_soc_dai *dai;
        int ret = 0;
        int i;

        /* Set stream pointer on all DAIs */
        for_each_rtd_dais(rtd, i, dai) {
                ret = snd_soc_dai_set_sdw_stream(dai, sdw_stream, substream->stream);
                if (ret < 0) {
                        dev_err(rtd->dev, "failed to set stream pointer on dai %s\n", dai->name);
                        break;
                }
        }

        return ret;
}

/**
 * sdw_startup_stream() - Startup SoundWire stream
 *
 * @sdw_substream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
int sdw_startup_stream(void *sdw_substream)
{
        struct snd_pcm_substream *substream = sdw_substream;
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct sdw_stream_runtime *sdw_stream;
        char *name;
        int ret;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                name = kasprintf(GFP_KERNEL, "%s-Playback", substream->name);
        else
                name = kasprintf(GFP_KERNEL, "%s-Capture", substream->name);

        if (!name)
                return -ENOMEM;

        sdw_stream = sdw_alloc_stream(name);
        if (!sdw_stream) {
                dev_err(rtd->dev, "alloc stream failed for substream DAI %s\n", substream->name);
                ret = -ENOMEM;
                goto error;
        }

        ret = set_stream(substream, sdw_stream);
        if (ret < 0)
                goto release_stream;
        return 0;

release_stream:
        sdw_release_stream(sdw_stream);
        set_stream(substream, NULL);
error:
        kfree(name);
        return ret;
}
EXPORT_SYMBOL(sdw_startup_stream);

/**
 * sdw_shutdown_stream() - Shutdown SoundWire stream
 *
 * @sdw_substream: Soundwire stream
 *
 * Documentation/driver-api/soundwire/stream.rst explains this API in detail
 */
void sdw_shutdown_stream(void *sdw_substream)
{
        struct snd_pcm_substream *substream = sdw_substream;
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct sdw_stream_runtime *sdw_stream;
        struct snd_soc_dai *dai;

        /* Find stream from first CPU DAI */
        dai = asoc_rtd_to_cpu(rtd, 0);

        sdw_stream = snd_soc_dai_get_sdw_stream(dai, substream->stream);

        if (IS_ERR(sdw_stream)) {
                dev_err(rtd->dev, "no stream found for DAI %s\n", dai->name);
                return;
        }

        /* release memory */
        kfree(sdw_stream->name);
        sdw_release_stream(sdw_stream);

        /* clear DAI data */
        set_stream(substream, NULL);
}
EXPORT_SYMBOL(sdw_shutdown_stream);