Documentation: Add documentation for Processor MMIO Stale Data

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

// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
// Copyright(c) 2015-17 Intel Corporation.

#include <linux/acpi.h>
#include <linux/delay.h>
#include <linux/mod_devicetable.h>
#include <linux/pm_runtime.h>
#include <linux/soundwire/sdw_registers.h>
#include <linux/soundwire/sdw.h>
#include "bus.h"
#include "sysfs_local.h"

static DEFINE_IDA(sdw_ida);

static int sdw_get_id(struct sdw_bus *bus)
{
        int rc = ida_alloc(&sdw_ida, GFP_KERNEL);

        if (rc < 0)
                return rc;

        bus->id = rc;
        return 0;
}

/**
 * sdw_bus_master_add() - add a bus Master instance
 * @bus: bus instance
 * @parent: parent device
 * @fwnode: firmware node handle
 *
 * Initializes the bus instance, read properties and create child
 * devices.
 */
int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,
                       struct fwnode_handle *fwnode)
{
        struct sdw_master_prop *prop = NULL;
        int ret;

        if (!parent) {
                pr_err("SoundWire parent device is not set\n");
                return -ENODEV;
        }

        ret = sdw_get_id(bus);
        if (ret < 0) {
                dev_err(parent, "Failed to get bus id\n");
                return ret;
        }

        ret = sdw_master_device_add(bus, parent, fwnode);
        if (ret < 0) {
                dev_err(parent, "Failed to add master device at link %d\n",
                        bus->link_id);
                return ret;
        }

        if (!bus->ops) {
                dev_err(bus->dev, "SoundWire Bus ops are not set\n");
                return -EINVAL;
        }

        if (!bus->compute_params) {
                dev_err(bus->dev,
                        "Bandwidth allocation not configured, compute_params no set\n");
                return -EINVAL;
        }

        mutex_init(&bus->msg_lock);
        mutex_init(&bus->bus_lock);
        INIT_LIST_HEAD(&bus->slaves);
        INIT_LIST_HEAD(&bus->m_rt_list);

        /*
         * Initialize multi_link flag
         * TODO: populate this flag by reading property from FW node
         */
        bus->multi_link = false;
        if (bus->ops->read_prop) {
                ret = bus->ops->read_prop(bus);
                if (ret < 0) {
                        dev_err(bus->dev,
                                "Bus read properties failed:%d\n", ret);
                        return ret;
                }
        }

        sdw_bus_debugfs_init(bus);

        /*
         * Device numbers in SoundWire are 0 through 15. Enumeration device
         * number (0), Broadcast device number (15), Group numbers (12 and
         * 13) and Master device number (14) are not used for assignment so
         * mask these and other higher bits.
         */

        /* Set higher order bits */
        *bus->assigned = ~GENMASK(SDW_BROADCAST_DEV_NUM, SDW_ENUM_DEV_NUM);

        /* Set enumuration device number and broadcast device number */
        set_bit(SDW_ENUM_DEV_NUM, bus->assigned);
        set_bit(SDW_BROADCAST_DEV_NUM, bus->assigned);

        /* Set group device numbers and master device number */
        set_bit(SDW_GROUP12_DEV_NUM, bus->assigned);
        set_bit(SDW_GROUP13_DEV_NUM, bus->assigned);
        set_bit(SDW_MASTER_DEV_NUM, bus->assigned);

        /*
         * SDW is an enumerable bus, but devices can be powered off. So,
         * they won't be able to report as present.
         *
         * Create Slave devices based on Slaves described in
         * the respective firmware (ACPI/DT)
         */
        if (IS_ENABLED(CONFIG_ACPI) && ACPI_HANDLE(bus->dev))
                ret = sdw_acpi_find_slaves(bus);
        else if (IS_ENABLED(CONFIG_OF) && bus->dev->of_node)
                ret = sdw_of_find_slaves(bus);
        else
                ret = -ENOTSUPP; /* No ACPI/DT so error out */

        if (ret < 0) {
                dev_err(bus->dev, "Finding slaves failed:%d\n", ret);
                return ret;
        }

        /*
         * Initialize clock values based on Master properties. The max
         * frequency is read from max_clk_freq property. Current assumption
         * is that the bus will start at highest clock frequency when
         * powered on.
         *
         * Default active bank will be 0 as out of reset the Slaves have
         * to start with bank 0 (Table 40 of Spec)
         */
        prop = &bus->prop;
        bus->params.max_dr_freq = prop->max_clk_freq * SDW_DOUBLE_RATE_FACTOR;
        bus->params.curr_dr_freq = bus->params.max_dr_freq;
        bus->params.curr_bank = SDW_BANK0;
        bus->params.next_bank = SDW_BANK1;

        return 0;
}
EXPORT_SYMBOL(sdw_bus_master_add);

static int sdw_delete_slave(struct device *dev, void *data)
{
        struct sdw_slave *slave = dev_to_sdw_dev(dev);
        struct sdw_bus *bus = slave->bus;

        pm_runtime_disable(dev);

        sdw_slave_debugfs_exit(slave);

        mutex_lock(&bus->bus_lock);

        if (slave->dev_num) /* clear dev_num if assigned */
                clear_bit(slave->dev_num, bus->assigned);

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

        device_unregister(dev);
        return 0;
}

/**
 * sdw_bus_master_delete() - delete the bus master instance
 * @bus: bus to be deleted
 *
 * Remove the instance, delete the child devices.
 */
void sdw_bus_master_delete(struct sdw_bus *bus)
{
        device_for_each_child(bus->dev, NULL, sdw_delete_slave);
        sdw_master_device_del(bus);

        sdw_bus_debugfs_exit(bus);
        ida_free(&sdw_ida, bus->id);
}
EXPORT_SYMBOL(sdw_bus_master_delete);

/*
 * SDW IO Calls
 */

static inline int find_response_code(enum sdw_command_response resp)
{
        switch (resp) {
        case SDW_CMD_OK:
                return 0;

        case SDW_CMD_IGNORED:
                return -ENODATA;

        case SDW_CMD_TIMEOUT:
                return -ETIMEDOUT;

        default:
                return -EIO;
        }
}

static inline int do_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
        int retry = bus->prop.err_threshold;
        enum sdw_command_response resp;
        int ret = 0, i;

        for (i = 0; i <= retry; i++) {
                resp = bus->ops->xfer_msg(bus, msg);
                ret = find_response_code(resp);

                /* if cmd is ok or ignored return */
                if (ret == 0 || ret == -ENODATA)
                        return ret;
        }

        return ret;
}

static inline int do_transfer_defer(struct sdw_bus *bus,
                                    struct sdw_msg *msg,
                                    struct sdw_defer *defer)
{
        int retry = bus->prop.err_threshold;
        enum sdw_command_response resp;
        int ret = 0, i;

        defer->msg = msg;
        defer->length = msg->len;
        init_completion(&defer->complete);

        for (i = 0; i <= retry; i++) {
                resp = bus->ops->xfer_msg_defer(bus, msg, defer);
                ret = find_response_code(resp);
                /* if cmd is ok or ignored return */
                if (ret == 0 || ret == -ENODATA)
                        return ret;
        }

        return ret;
}

static int sdw_reset_page(struct sdw_bus *bus, u16 dev_num)
{
        int retry = bus->prop.err_threshold;
        enum sdw_command_response resp;
        int ret = 0, i;

        for (i = 0; i <= retry; i++) {
                resp = bus->ops->reset_page_addr(bus, dev_num);
                ret = find_response_code(resp);
                /* if cmd is ok or ignored return */
                if (ret == 0 || ret == -ENODATA)
                        return ret;
        }

        return ret;
}

static int sdw_transfer_unlocked(struct sdw_bus *bus, struct sdw_msg *msg)
{
        int ret;

        ret = do_transfer(bus, msg);
        if (ret != 0 && ret != -ENODATA)
                dev_err(bus->dev, "trf on Slave %d failed:%d %s addr %x count %d\n",
                        msg->dev_num, ret,
                        (msg->flags & SDW_MSG_FLAG_WRITE) ? "write" : "read",
                        msg->addr, msg->len);

        if (msg->page)
                sdw_reset_page(bus, msg->dev_num);

        return ret;
}

/**
 * sdw_transfer() - Synchronous transfer message to a SDW Slave device
 * @bus: SDW bus
 * @msg: SDW message to be xfered
 */
int sdw_transfer(struct sdw_bus *bus, struct sdw_msg *msg)
{
        int ret;

        mutex_lock(&bus->msg_lock);

        ret = sdw_transfer_unlocked(bus, msg);

        mutex_unlock(&bus->msg_lock);

        return ret;
}

/**
 * sdw_transfer_defer() - Asynchronously transfer message to a SDW Slave device
 * @bus: SDW bus
 * @msg: SDW message to be xfered
 * @defer: Defer block for signal completion
 *
 * Caller needs to hold the msg_lock lock while calling this
 */
int sdw_transfer_defer(struct sdw_bus *bus, struct sdw_msg *msg,
                       struct sdw_defer *defer)
{
        int ret;

        if (!bus->ops->xfer_msg_defer)
                return -ENOTSUPP;

        ret = do_transfer_defer(bus, msg, defer);
        if (ret != 0 && ret != -ENODATA)
                dev_err(bus->dev, "Defer trf on Slave %d failed:%d\n",
                        msg->dev_num, ret);

        if (msg->page)
                sdw_reset_page(bus, msg->dev_num);

        return ret;
}

int sdw_fill_msg(struct sdw_msg *msg, struct sdw_slave *slave,
                 u32 addr, size_t count, u16 dev_num, u8 flags, u8 *buf)
{
        memset(msg, 0, sizeof(*msg));
        msg->addr = addr; /* addr is 16 bit and truncated here */
        msg->len = count;
        msg->dev_num = dev_num;
        msg->flags = flags;
        msg->buf = buf;

        if (addr < SDW_REG_NO_PAGE) /* no paging area */
                return 0;

        if (addr >= SDW_REG_MAX) { /* illegal addr */
                pr_err("SDW: Invalid address %x passed\n", addr);
                return -EINVAL;
        }

        if (addr < SDW_REG_OPTIONAL_PAGE) { /* 32k but no page */
                if (slave && !slave->prop.paging_support)
                        return 0;
                /* no need for else as that will fall-through to paging */
        }

        /* paging mandatory */
        if (dev_num == SDW_ENUM_DEV_NUM || dev_num == SDW_BROADCAST_DEV_NUM) {
                pr_err("SDW: Invalid device for paging :%d\n", dev_num);
                return -EINVAL;
        }

        if (!slave) {
                pr_err("SDW: No slave for paging addr\n");
                return -EINVAL;
        }

        if (!slave->prop.paging_support) {
                dev_err(&slave->dev,
                        "address %x needs paging but no support\n", addr);
                return -EINVAL;
        }

        msg->addr_page1 = FIELD_GET(SDW_SCP_ADDRPAGE1_MASK, addr);
        msg->addr_page2 = FIELD_GET(SDW_SCP_ADDRPAGE2_MASK, addr);
        msg->addr |= BIT(15);
        msg->page = true;

        return 0;
}

/*
 * Read/Write IO functions.
 * no_pm versions can only be called by the bus, e.g. while enumerating or
 * handling suspend-resume sequences.
 * all clients need to use the pm versions
 */

static int
sdw_nread_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
        struct sdw_msg msg;
        int ret;

        ret = sdw_fill_msg(&msg, slave, addr, count,
                           slave->dev_num, SDW_MSG_FLAG_READ, val);
        if (ret < 0)
                return ret;

        ret = sdw_transfer(slave->bus, &msg);
        if (slave->is_mockup_device)
                ret = 0;
        return ret;
}

static int
sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, const u8 *val)
{
        struct sdw_msg msg;
        int ret;

        ret = sdw_fill_msg(&msg, slave, addr, count,
                           slave->dev_num, SDW_MSG_FLAG_WRITE, (u8 *)val);
        if (ret < 0)
                return ret;

        ret = sdw_transfer(slave->bus, &msg);
        if (slave->is_mockup_device)
                ret = 0;
        return ret;
}

int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
{
        return sdw_nwrite_no_pm(slave, addr, 1, &value);
}
EXPORT_SYMBOL(sdw_write_no_pm);

static int
sdw_bread_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr)
{
        struct sdw_msg msg;
        u8 buf;
        int ret;

        ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
                           SDW_MSG_FLAG_READ, &buf);
        if (ret < 0)
                return ret;

        ret = sdw_transfer(bus, &msg);
        if (ret < 0)
                return ret;

        return buf;
}

static int
sdw_bwrite_no_pm(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value)
{
        struct sdw_msg msg;
        int ret;

        ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
                           SDW_MSG_FLAG_WRITE, &value);
        if (ret < 0)
                return ret;

        return sdw_transfer(bus, &msg);
}

int sdw_bread_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr)
{
        struct sdw_msg msg;
        u8 buf;
        int ret;

        ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
                           SDW_MSG_FLAG_READ, &buf);
        if (ret < 0)
                return ret;

        ret = sdw_transfer_unlocked(bus, &msg);
        if (ret < 0)
                return ret;

        return buf;
}
EXPORT_SYMBOL(sdw_bread_no_pm_unlocked);

int sdw_bwrite_no_pm_unlocked(struct sdw_bus *bus, u16 dev_num, u32 addr, u8 value)
{
        struct sdw_msg msg;
        int ret;

        ret = sdw_fill_msg(&msg, NULL, addr, 1, dev_num,
                           SDW_MSG_FLAG_WRITE, &value);
        if (ret < 0)
                return ret;

        return sdw_transfer_unlocked(bus, &msg);
}
EXPORT_SYMBOL(sdw_bwrite_no_pm_unlocked);

int sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
{
        u8 buf;
        int ret;

        ret = sdw_nread_no_pm(slave, addr, 1, &buf);
        if (ret < 0)
                return ret;
        else
                return buf;
}
EXPORT_SYMBOL(sdw_read_no_pm);

int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
{
        int tmp;

        tmp = sdw_read_no_pm(slave, addr);
        if (tmp < 0)
                return tmp;

        tmp = (tmp & ~mask) | val;
        return sdw_write_no_pm(slave, addr, tmp);
}
EXPORT_SYMBOL(sdw_update_no_pm);

/* Read-Modify-Write Slave register */
int sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
{
        int tmp;

        tmp = sdw_read(slave, addr);
        if (tmp < 0)
                return tmp;

        tmp = (tmp & ~mask) | val;
        return sdw_write(slave, addr, tmp);
}
EXPORT_SYMBOL(sdw_update);

/**
 * sdw_nread() - Read "n" contiguous SDW Slave registers
 * @slave: SDW Slave
 * @addr: Register address
 * @count: length
 * @val: Buffer for values to be read
 */
int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
{
        int ret;

        ret = pm_runtime_get_sync(&slave->dev);
        if (ret < 0 && ret != -EACCES) {
                pm_runtime_put_noidle(&slave->dev);
                return ret;
        }

        ret = sdw_nread_no_pm(slave, addr, count, val);

        pm_runtime_mark_last_busy(&slave->dev);
        pm_runtime_put(&slave->dev);

        return ret;
}
EXPORT_SYMBOL(sdw_nread);

/**
 * sdw_nwrite() - Write "n" contiguous SDW Slave registers
 * @slave: SDW Slave
 * @addr: Register address
 * @count: length
 * @val: Buffer for values to be written
 */
int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, const u8 *val)
{
        int ret;

        ret = pm_runtime_get_sync(&slave->dev);
        if (ret < 0 && ret != -EACCES) {
                pm_runtime_put_noidle(&slave->dev);
                return ret;
        }

        ret = sdw_nwrite_no_pm(slave, addr, count, val);

        pm_runtime_mark_last_busy(&slave->dev);
        pm_runtime_put(&slave->dev);

        return ret;
}
EXPORT_SYMBOL(sdw_nwrite);

/**
 * sdw_read() - Read a SDW Slave register
 * @slave: SDW Slave
 * @addr: Register address
 */
int sdw_read(struct sdw_slave *slave, u32 addr)
{
        u8 buf;
        int ret;

        ret = sdw_nread(slave, addr, 1, &buf);
        if (ret < 0)
                return ret;

        return buf;
}
EXPORT_SYMBOL(sdw_read);

/**
 * sdw_write() - Write a SDW Slave register
 * @slave: SDW Slave
 * @addr: Register address
 * @value: Register value
 */
int sdw_write(struct sdw_slave *slave, u32 addr, u8 value)
{
        return sdw_nwrite(slave, addr, 1, &value);
}
EXPORT_SYMBOL(sdw_write);

/*
 * SDW alert handling
 */

/* called with bus_lock held */
static struct sdw_slave *sdw_get_slave(struct sdw_bus *bus, int i)
{
        struct sdw_slave *slave;

        list_for_each_entry(slave, &bus->slaves, node) {
                if (slave->dev_num == i)
                        return slave;
        }

        return NULL;
}

int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id)
{
        if (slave->id.mfg_id != id.mfg_id ||
            slave->id.part_id != id.part_id ||
            slave->id.class_id != id.class_id ||
            (slave->id.unique_id != SDW_IGNORED_UNIQUE_ID &&
             slave->id.unique_id != id.unique_id))
                return -ENODEV;

        return 0;
}
EXPORT_SYMBOL(sdw_compare_devid);

/* called with bus_lock held */
static int sdw_get_device_num(struct sdw_slave *slave)
{
        int bit;

        bit = find_first_zero_bit(slave->bus->assigned, SDW_MAX_DEVICES);
        if (bit == SDW_MAX_DEVICES) {
                bit = -ENODEV;
                goto err;
        }

        /*
         * Do not update dev_num in Slave data structure here,
         * Update once program dev_num is successful
         */
        set_bit(bit, slave->bus->assigned);

err:
        return bit;
}

static int sdw_assign_device_num(struct sdw_slave *slave)
{
        struct sdw_bus *bus = slave->bus;
        int ret, dev_num;
        bool new_device = false;

        /* check first if device number is assigned, if so reuse that */
        if (!slave->dev_num) {
                if (!slave->dev_num_sticky) {
                        mutex_lock(&slave->bus->bus_lock);
                        dev_num = sdw_get_device_num(slave);
                        mutex_unlock(&slave->bus->bus_lock);
                        if (dev_num < 0) {
                                dev_err(bus->dev, "Get dev_num failed: %d\n",
                                        dev_num);
                                return dev_num;
                        }
                        slave->dev_num = dev_num;
                        slave->dev_num_sticky = dev_num;
                        new_device = true;
                } else {
                        slave->dev_num = slave->dev_num_sticky;
                }
        }

        if (!new_device)
                dev_dbg(bus->dev,
                        "Slave already registered, reusing dev_num:%d\n",
                        slave->dev_num);

        /* Clear the slave->dev_num to transfer message on device 0 */
        dev_num = slave->dev_num;
        slave->dev_num = 0;

        ret = sdw_write_no_pm(slave, SDW_SCP_DEVNUMBER, dev_num);
        if (ret < 0) {
                dev_err(bus->dev, "Program device_num %d failed: %d\n",
                        dev_num, ret);
                return ret;
        }

        /* After xfer of msg, restore dev_num */
        slave->dev_num = slave->dev_num_sticky;

        return 0;
}

void sdw_extract_slave_id(struct sdw_bus *bus,
                          u64 addr, struct sdw_slave_id *id)
{
        dev_dbg(bus->dev, "SDW Slave Addr: %llx\n", addr);

        id->sdw_version = SDW_VERSION(addr);
        id->unique_id = SDW_UNIQUE_ID(addr);
        id->mfg_id = SDW_MFG_ID(addr);
        id->part_id = SDW_PART_ID(addr);
        id->class_id = SDW_CLASS_ID(addr);

        dev_dbg(bus->dev,
                "SDW Slave class_id 0x%02x, mfg_id 0x%04x, part_id 0x%04x, unique_id 0x%x, version 0x%x\n",
                id->class_id, id->mfg_id, id->part_id, id->unique_id, id->sdw_version);
}
EXPORT_SYMBOL(sdw_extract_slave_id);

static int sdw_program_device_num(struct sdw_bus *bus)
{
        u8 buf[SDW_NUM_DEV_ID_REGISTERS] = {0};
        struct sdw_slave *slave, *_s;
        struct sdw_slave_id id;
        struct sdw_msg msg;
        bool found;
        int count = 0, ret;
        u64 addr;

        /* No Slave, so use raw xfer api */
        ret = sdw_fill_msg(&msg, NULL, SDW_SCP_DEVID_0,
                           SDW_NUM_DEV_ID_REGISTERS, 0, SDW_MSG_FLAG_READ, buf);
        if (ret < 0)
                return ret;

        do {
                ret = sdw_transfer(bus, &msg);
                if (ret == -ENODATA) { /* end of device id reads */
                        dev_dbg(bus->dev, "No more devices to enumerate\n");
                        ret = 0;
                        break;
                }
                if (ret < 0) {
                        dev_err(bus->dev, "DEVID read fail:%d\n", ret);
                        break;
                }

                /*
                 * Construct the addr and extract. Cast the higher shift
                 * bits to avoid truncation due to size limit.
                 */
                addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) |
                        ((u64)buf[2] << 24) | ((u64)buf[1] << 32) |
                        ((u64)buf[0] << 40);

                sdw_extract_slave_id(bus, addr, &id);

                found = false;
                /* Now compare with entries */
                list_for_each_entry_safe(slave, _s, &bus->slaves, node) {
                        if (sdw_compare_devid(slave, id) == 0) {
                                found = true;

                                /*
                                 * Assign a new dev_num to this Slave and
                                 * not mark it present. It will be marked
                                 * present after it reports ATTACHED on new
                                 * dev_num
                                 */
                                ret = sdw_assign_device_num(slave);
                                if (ret < 0) {
                                        dev_err(bus->dev,
                                                "Assign dev_num failed:%d\n",
                                                ret);
                                        return ret;
                                }

                                break;
                        }
                }

                if (!found) {
                        /* TODO: Park this device in Group 13 */

                        /*
                         * add Slave device even if there is no platform
                         * firmware description. There will be no driver probe
                         * but the user/integration will be able to see the
                         * device, enumeration status and device number in sysfs
                         */
                        sdw_slave_add(bus, &id, NULL);

                        dev_err(bus->dev, "Slave Entry not found\n");
                }

                count++;

                /*
                 * Check till error out or retry (count) exhausts.
                 * Device can drop off and rejoin during enumeration
                 * so count till twice the bound.
                 */

        } while (ret == 0 && count < (SDW_MAX_DEVICES * 2));

        return ret;
}

static void sdw_modify_slave_status(struct sdw_slave *slave,
                                    enum sdw_slave_status status)
{
        struct sdw_bus *bus = slave->bus;

        mutex_lock(&bus->bus_lock);

        dev_vdbg(bus->dev,
                 "%s: changing status slave %d status %d new status %d\n",
                 __func__, slave->dev_num, slave->status, status);

        if (status == SDW_SLAVE_UNATTACHED) {
                dev_dbg(&slave->dev,
                        "%s: initializing enumeration and init completion for Slave %d\n",
                        __func__, slave->dev_num);

                init_completion(&slave->enumeration_complete);
                init_completion(&slave->initialization_complete);

        } else if ((status == SDW_SLAVE_ATTACHED) &&
                   (slave->status == SDW_SLAVE_UNATTACHED)) {
                dev_dbg(&slave->dev,
                        "%s: signaling enumeration completion for Slave %d\n",
                        __func__, slave->dev_num);

                complete(&slave->enumeration_complete);
        }
        slave->status = status;
        mutex_unlock(&bus->bus_lock);
}

static int sdw_slave_clk_stop_callback(struct sdw_slave *slave,
                                       enum sdw_clk_stop_mode mode,
                                       enum sdw_clk_stop_type type)
{
        int ret;

        if (slave->ops && slave->ops->clk_stop) {
                ret = slave->ops->clk_stop(slave, mode, type);
                if (ret < 0)
                        return ret;
        }

        return 0;
}

static int sdw_slave_clk_stop_prepare(struct sdw_slave *slave,
                                      enum sdw_clk_stop_mode mode,
                                      bool prepare)
{
        bool wake_en;
        u32 val = 0;
        int ret;

        wake_en = slave->prop.wake_capable;

        if (prepare) {
                val = SDW_SCP_SYSTEMCTRL_CLK_STP_PREP;

                if (mode == SDW_CLK_STOP_MODE1)
                        val |= SDW_SCP_SYSTEMCTRL_CLK_STP_MODE1;

                if (wake_en)
                        val |= SDW_SCP_SYSTEMCTRL_WAKE_UP_EN;
        } else {
                ret = sdw_read_no_pm(slave, SDW_SCP_SYSTEMCTRL);
                if (ret < 0) {
                        if (ret != -ENODATA)
                                dev_err(&slave->dev, "SDW_SCP_SYSTEMCTRL read failed:%d\n", ret);
                        return ret;
                }
                val = ret;
                val &= ~(SDW_SCP_SYSTEMCTRL_CLK_STP_PREP);
        }

        ret = sdw_write_no_pm(slave, SDW_SCP_SYSTEMCTRL, val);

        if (ret < 0 && ret != -ENODATA)
                dev_err(&slave->dev, "SDW_SCP_SYSTEMCTRL write failed:%d\n", ret);

        return ret;
}

static int sdw_bus_wait_for_clk_prep_deprep(struct sdw_bus *bus, u16 dev_num)
{
        int retry = bus->clk_stop_timeout;
        int val;

        do {
                val = sdw_bread_no_pm(bus, dev_num, SDW_SCP_STAT);
                if (val < 0) {
                        if (val != -ENODATA)
                                dev_err(bus->dev, "SDW_SCP_STAT bread failed:%d\n", val);
                        return val;
                }
                val &= SDW_SCP_STAT_CLK_STP_NF;
                if (!val) {
                        dev_dbg(bus->dev, "clock stop prep/de-prep done slave:%d\n",
                                dev_num);
                        return 0;
                }

                usleep_range(1000, 1500);
                retry--;
        } while (retry);

        dev_err(bus->dev, "clock stop prep/de-prep failed slave:%d\n",
                dev_num);

        return -ETIMEDOUT;
}

/**
 * sdw_bus_prep_clk_stop: prepare Slave(s) for clock stop
 *
 * @bus: SDW bus instance
 *
 * Query Slave for clock stop mode and prepare for that mode.
 */
int sdw_bus_prep_clk_stop(struct sdw_bus *bus)
{
        bool simple_clk_stop = true;
        struct sdw_slave *slave;
        bool is_slave = false;
        int ret = 0;

        /*
         * In order to save on transition time, prepare
         * each Slave and then wait for all Slave(s) to be
         * prepared for clock stop.
         * If one of the Slave devices has lost sync and
         * replies with Command Ignored/-ENODATA, we continue
         * the loop
         */
        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
                        continue;

                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;

                /* Identify if Slave(s) are available on Bus */
                is_slave = true;

                ret = sdw_slave_clk_stop_callback(slave,
                                                  SDW_CLK_STOP_MODE0,
                                                  SDW_CLK_PRE_PREPARE);
                if (ret < 0 && ret != -ENODATA) {
                        dev_err(&slave->dev, "clock stop pre-prepare cb failed:%d\n", ret);
                        return ret;
                }

                /* Only prepare a Slave device if needed */
                if (!slave->prop.simple_clk_stop_capable) {
                        simple_clk_stop = false;

                        ret = sdw_slave_clk_stop_prepare(slave,
                                                         SDW_CLK_STOP_MODE0,
                                                         true);
                        if (ret < 0 && ret != -ENODATA) {
                                dev_err(&slave->dev, "clock stop prepare failed:%d\n", ret);
                                return ret;
                        }
                }
        }

        /* Skip remaining clock stop preparation if no Slave is attached */
        if (!is_slave)
                return 0;

        /*
         * Don't wait for all Slaves to be ready if they follow the simple
         * state machine
         */
        if (!simple_clk_stop) {
                ret = sdw_bus_wait_for_clk_prep_deprep(bus,
                                                       SDW_BROADCAST_DEV_NUM);
                /*
                 * if there are no Slave devices present and the reply is
                 * Command_Ignored/-ENODATA, we don't need to continue with the
                 * flow and can just return here. The error code is not modified
                 * and its handling left as an exercise for the caller.
                 */
                if (ret < 0)
                        return ret;
        }

        /* Inform slaves that prep is done */
        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
                        continue;

                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;

                ret = sdw_slave_clk_stop_callback(slave,
                                                  SDW_CLK_STOP_MODE0,
                                                  SDW_CLK_POST_PREPARE);

                if (ret < 0 && ret != -ENODATA) {
                        dev_err(&slave->dev, "clock stop post-prepare cb failed:%d\n", ret);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL(sdw_bus_prep_clk_stop);

/**
 * sdw_bus_clk_stop: stop bus clock
 *
 * @bus: SDW bus instance
 *
 * After preparing the Slaves for clock stop, stop the clock by broadcasting
 * write to SCP_CTRL register.
 */
int sdw_bus_clk_stop(struct sdw_bus *bus)
{
        int ret;

        /*
         * broadcast clock stop now, attached Slaves will ACK this,
         * unattached will ignore
         */
        ret = sdw_bwrite_no_pm(bus, SDW_BROADCAST_DEV_NUM,
                               SDW_SCP_CTRL, SDW_SCP_CTRL_CLK_STP_NOW);
        if (ret < 0) {
                if (ret != -ENODATA)
                        dev_err(bus->dev, "ClockStopNow Broadcast msg failed %d\n", ret);
                return ret;
        }

        return 0;
}
EXPORT_SYMBOL(sdw_bus_clk_stop);

/**
 * sdw_bus_exit_clk_stop: Exit clock stop mode
 *
 * @bus: SDW bus instance
 *
 * This De-prepares the Slaves by exiting Clock Stop Mode 0. For the Slaves
 * exiting Clock Stop Mode 1, they will be de-prepared after they enumerate
 * back.
 */
int sdw_bus_exit_clk_stop(struct sdw_bus *bus)
{
        bool simple_clk_stop = true;
        struct sdw_slave *slave;
        bool is_slave = false;
        int ret;

        /*
         * In order to save on transition time, de-prepare
         * each Slave and then wait for all Slave(s) to be
         * de-prepared after clock resume.
         */
        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
                        continue;

                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;

                /* Identify if Slave(s) are available on Bus */
                is_slave = true;

                ret = sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,
                                                  SDW_CLK_PRE_DEPREPARE);
                if (ret < 0)
                        dev_warn(&slave->dev, "clock stop pre-deprepare cb failed:%d\n", ret);

                /* Only de-prepare a Slave device if needed */
                if (!slave->prop.simple_clk_stop_capable) {
                        simple_clk_stop = false;

                        ret = sdw_slave_clk_stop_prepare(slave, SDW_CLK_STOP_MODE0,
                                                         false);

                        if (ret < 0)
                                dev_warn(&slave->dev, "clock stop deprepare failed:%d\n", ret);
                }
        }

        /* Skip remaining clock stop de-preparation if no Slave is attached */
        if (!is_slave)
                return 0;

        /*
         * Don't wait for all Slaves to be ready if they follow the simple
         * state machine
         */
        if (!simple_clk_stop) {
                ret = sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);
                if (ret < 0)
                        dev_warn(bus->dev, "clock stop deprepare wait failed:%d\n", ret);
        }

        list_for_each_entry(slave, &bus->slaves, node) {
                if (!slave->dev_num)
                        continue;

                if (slave->status != SDW_SLAVE_ATTACHED &&
                    slave->status != SDW_SLAVE_ALERT)
                        continue;

                ret = sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,
                                                  SDW_CLK_POST_DEPREPARE);
                if (ret < 0)
                        dev_warn(&slave->dev, "clock stop post-deprepare cb failed:%d\n", ret);
        }

        return 0;
}
EXPORT_SYMBOL(sdw_bus_exit_clk_stop);

int sdw_configure_dpn_intr(struct sdw_slave *slave,
                           int port, bool enable, int mask)
{
        u32 addr;
        int ret;
        u8 val = 0;

        if (slave->bus->params.s_data_mode != SDW_PORT_DATA_MODE_NORMAL) {
                dev_dbg(&slave->dev, "TEST FAIL interrupt %s\n",
                        enable ? "on" : "off");
                mask |= SDW_DPN_INT_TEST_FAIL;
        }

        addr = SDW_DPN_INTMASK(port);

        /* Set/Clear port ready interrupt mask */
        if (enable) {
                val |= mask;
                val |= SDW_DPN_INT_PORT_READY;
        } else {
                val &= ~(mask);
                val &= ~SDW_DPN_INT_PORT_READY;
        }

        ret = sdw_update(slave, addr, (mask | SDW_DPN_INT_PORT_READY), val);
        if (ret < 0)
                dev_err(&slave->dev,
                        "SDW_DPN_INTMASK write failed:%d\n", val);

        return ret;
}

static int sdw_slave_set_frequency(struct sdw_slave *slave)
{
        u32 mclk_freq = slave->bus->prop.mclk_freq;
        u32 curr_freq = slave->bus->params.curr_dr_freq >> 1;
        unsigned int scale;
        u8 scale_index;
        u8 base;
        int ret;

        /*
         * frequency base and scale registers are required for SDCA
         * devices. They may also be used for 1.2+/non-SDCA devices,
         * but we will need a DisCo property to cover this case
         */
        if (!slave->id.class_id)
                return 0;

        if (!mclk_freq) {
                dev_err(&slave->dev,
                        "no bus MCLK, cannot set SDW_SCP_BUS_CLOCK_BASE\n");
                return -EINVAL;
        }

        /*
         * map base frequency using Table 89 of SoundWire 1.2 spec.
         * The order of the tests just follows the specification, this
         * is not a selection between possible values or a search for
         * the best value but just a mapping.  Only one case per platform
         * is relevant.
         * Some BIOS have inconsistent values for mclk_freq but a
         * correct root so we force the mclk_freq to avoid variations.
         */
        if (!(19200000 % mclk_freq)) {
                mclk_freq = 19200000;
                base = SDW_SCP_BASE_CLOCK_19200000_HZ;
        } else if (!(24000000 % mclk_freq)) {
                mclk_freq = 24000000;
                base = SDW_SCP_BASE_CLOCK_24000000_HZ;
        } else if (!(24576000 % mclk_freq)) {
                mclk_freq = 24576000;
                base = SDW_SCP_BASE_CLOCK_24576000_HZ;
        } else if (!(22579200 % mclk_freq)) {
                mclk_freq = 22579200;
                base = SDW_SCP_BASE_CLOCK_22579200_HZ;
        } else if (!(32000000 % mclk_freq)) {
                mclk_freq = 32000000;
                base = SDW_SCP_BASE_CLOCK_32000000_HZ;
        } else {
                dev_err(&slave->dev,
                        "Unsupported clock base, mclk %d\n",
                        mclk_freq);
                return -EINVAL;
        }

        if (mclk_freq % curr_freq) {
                dev_err(&slave->dev,
                        "mclk %d is not multiple of bus curr_freq %d\n",
                        mclk_freq, curr_freq);
                return -EINVAL;
        }

        scale = mclk_freq / curr_freq;

        /*
         * map scale to Table 90 of SoundWire 1.2 spec - and check
         * that the scale is a power of two and maximum 64
         */
        scale_index = ilog2(scale);

        if (BIT(scale_index) != scale || scale_index > 6) {
                dev_err(&slave->dev,
                        "No match found for scale %d, bus mclk %d curr_freq %d\n",
                        scale, mclk_freq, curr_freq);
                return -EINVAL;
        }
        scale_index++;

        ret = sdw_write_no_pm(slave, SDW_SCP_BUS_CLOCK_BASE, base);
        if (ret < 0) {
                dev_err(&slave->dev,
                        "SDW_SCP_BUS_CLOCK_BASE write failed:%d\n", ret);
                return ret;
        }

        /* initialize scale for both banks */
        ret = sdw_write_no_pm(slave, SDW_SCP_BUSCLOCK_SCALE_B0, scale_index);
        if (ret < 0) {
                dev_err(&slave->dev,
                        "SDW_SCP_BUSCLOCK_SCALE_B0 write failed:%d\n", ret);
                return ret;
        }
        ret = sdw_write_no_pm(slave, SDW_SCP_BUSCLOCK_SCALE_B1, scale_index);
        if (ret < 0)
                dev_err(&slave->dev,
                        "SDW_SCP_BUSCLOCK_SCALE_B1 write failed:%d\n", ret);

        dev_dbg(&slave->dev,
                "Configured bus base %d, scale %d, mclk %d, curr_freq %d\n",
                base, scale_index, mclk_freq, curr_freq);

        return ret;
}

static int sdw_initialize_slave(struct sdw_slave *slave)
{
        struct sdw_slave_prop *prop = &slave->prop;
        int status;
        int ret;
        u8 val;

        ret = sdw_slave_set_frequency(slave);
        if (ret < 0)
                return ret;

        if (slave->bus->prop.quirks & SDW_MASTER_QUIRKS_CLEAR_INITIAL_CLASH) {
                /* Clear bus clash interrupt before enabling interrupt mask */
                status = sdw_read_no_pm(slave, SDW_SCP_INT1);
                if (status < 0) {
                        dev_err(&slave->dev,
                                "SDW_SCP_INT1 (BUS_CLASH) read failed:%d\n", status);
                        return status;
                }
                if (status & SDW_SCP_INT1_BUS_CLASH) {
                        dev_warn(&slave->dev, "Bus clash detected before INT mask is enabled\n");
                        ret = sdw_write_no_pm(slave, SDW_SCP_INT1, SDW_SCP_INT1_BUS_CLASH);
                        if (ret < 0) {
                                dev_err(&slave->dev,
                                        "SDW_SCP_INT1 (BUS_CLASH) write failed:%d\n", ret);
                                return ret;
                        }
                }
        }
        if ((slave->bus->prop.quirks & SDW_MASTER_QUIRKS_CLEAR_INITIAL_PARITY) &&
            !(slave->prop.quirks & SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY)) {
                /* Clear parity interrupt before enabling interrupt mask */
                status = sdw_read_no_pm(slave, SDW_SCP_INT1);
                if (status < 0) {
                        dev_err(&slave->dev,
                                "SDW_SCP_INT1 (PARITY) read failed:%d\n", status);
                        return status;
                }
                if (status & SDW_SCP_INT1_PARITY) {
                        dev_warn(&slave->dev, "PARITY error detected before INT mask is enabled\n");
                        ret = sdw_write_no_pm(slave, SDW_SCP_INT1, SDW_SCP_INT1_PARITY);
                        if (ret < 0) {
                                dev_err(&slave->dev,
                                        "SDW_SCP_INT1 (PARITY) write failed:%d\n", ret);
                                return ret;
                        }
                }
        }

        /*
         * Set SCP_INT1_MASK register, typically bus clash and
         * implementation-defined interrupt mask. The Parity detection
         * may not always be correct on startup so its use is
         * device-dependent, it might e.g. only be enabled in
         * steady-state after a couple of frames.
         */
        val = slave->prop.scp_int1_mask;

        /* Enable SCP interrupts */
        ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
        if (ret < 0) {
                dev_err(&slave->dev,
                        "SDW_SCP_INTMASK1 write failed:%d\n", ret);
                return ret;
        }

        /* No need to continue if DP0 is not present */
        if (!slave->prop.dp0_prop)
                return 0;

        /* Enable DP0 interrupts */
        val = prop->dp0_prop->imp_def_interrupts;
        val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;

        ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
        if (ret < 0)
                dev_err(&slave->dev,
                        "SDW_DP0_INTMASK read failed:%d\n", ret);
        return ret;
}

static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
{
        u8 clear, impl_int_mask;
        int status, status2, ret, count = 0;

        status = sdw_read_no_pm(slave, SDW_DP0_INT);
        if (status < 0) {
                dev_err(&slave->dev,
                        "SDW_DP0_INT read failed:%d\n", status);
                return status;
        }

        do {
                clear = status & ~SDW_DP0_INTERRUPTS;

                if (status & SDW_DP0_INT_TEST_FAIL) {
                        dev_err(&slave->dev, "Test fail for port 0\n");
                        clear |= SDW_DP0_INT_TEST_FAIL;
                }

                /*
                 * Assumption: PORT_READY interrupt will be received only for
                 * ports implementing Channel Prepare state machine (CP_SM)
                 */

                if (status & SDW_DP0_INT_PORT_READY) {
                        complete(&slave->port_ready[0]);
                        clear |= SDW_DP0_INT_PORT_READY;
                }

                if (status & SDW_DP0_INT_BRA_FAILURE) {
                        dev_err(&slave->dev, "BRA failed\n");
                        clear |= SDW_DP0_INT_BRA_FAILURE;
                }

                impl_int_mask = SDW_DP0_INT_IMPDEF1 |
                        SDW_DP0_INT_IMPDEF2 | SDW_DP0_INT_IMPDEF3;

                if (status & impl_int_mask) {
                        clear |= impl_int_mask;
                        *slave_status = clear;
                }

                /* clear the interrupts but don't touch reserved and SDCA_CASCADE fields */
                ret = sdw_write_no_pm(slave, SDW_DP0_INT, clear);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_DP0_INT write failed:%d\n", ret);
                        return ret;
                }

                /* Read DP0 interrupt again */
                status2 = sdw_read_no_pm(slave, SDW_DP0_INT);
                if (status2 < 0) {
                        dev_err(&slave->dev,
                                "SDW_DP0_INT read failed:%d\n", status2);
                        return status2;
                }
                /* filter to limit loop to interrupts identified in the first status read */
                status &= status2;

                count++;

                /* we can get alerts while processing so keep retrying */
        } while ((status & SDW_DP0_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));

        if (count == SDW_READ_INTR_CLEAR_RETRY)
                dev_warn(&slave->dev, "Reached MAX_RETRY on DP0 read\n");

        return ret;
}

static int sdw_handle_port_interrupt(struct sdw_slave *slave,
                                     int port, u8 *slave_status)
{
        u8 clear, impl_int_mask;
        int status, status2, ret, count = 0;
        u32 addr;

        if (port == 0)
                return sdw_handle_dp0_interrupt(slave, slave_status);

        addr = SDW_DPN_INT(port);
        status = sdw_read_no_pm(slave, addr);
        if (status < 0) {
                dev_err(&slave->dev,
                        "SDW_DPN_INT read failed:%d\n", status);

                return status;
        }

        do {
                clear = status & ~SDW_DPN_INTERRUPTS;

                if (status & SDW_DPN_INT_TEST_FAIL) {
                        dev_err(&slave->dev, "Test fail for port:%d\n", port);
                        clear |= SDW_DPN_INT_TEST_FAIL;
                }

                /*
                 * Assumption: PORT_READY interrupt will be received only
                 * for ports implementing CP_SM.
                 */
                if (status & SDW_DPN_INT_PORT_READY) {
                        complete(&slave->port_ready[port]);
                        clear |= SDW_DPN_INT_PORT_READY;
                }

                impl_int_mask = SDW_DPN_INT_IMPDEF1 |
                        SDW_DPN_INT_IMPDEF2 | SDW_DPN_INT_IMPDEF3;

                if (status & impl_int_mask) {
                        clear |= impl_int_mask;
                        *slave_status = clear;
                }

                /* clear the interrupt but don't touch reserved fields */
                ret = sdw_write_no_pm(slave, addr, clear);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_DPN_INT write failed:%d\n", ret);
                        return ret;
                }

                /* Read DPN interrupt again */
                status2 = sdw_read_no_pm(slave, addr);
                if (status2 < 0) {
                        dev_err(&slave->dev,
                                "SDW_DPN_INT read failed:%d\n", status2);
                        return status2;
                }
                /* filter to limit loop to interrupts identified in the first status read */
                status &= status2;

                count++;

                /* we can get alerts while processing so keep retrying */
        } while ((status & SDW_DPN_INTERRUPTS) && (count < SDW_READ_INTR_CLEAR_RETRY));

        if (count == SDW_READ_INTR_CLEAR_RETRY)
                dev_warn(&slave->dev, "Reached MAX_RETRY on port read");

        return ret;
}

static int sdw_handle_slave_alerts(struct sdw_slave *slave)
{
        struct sdw_slave_intr_status slave_intr;
        u8 clear = 0, bit, port_status[15] = {0};
        int port_num, stat, ret, count = 0;
        unsigned long port;
        bool slave_notify;
        u8 sdca_cascade = 0;
        u8 buf, buf2[2], _buf, _buf2[2];
        bool parity_check;
        bool parity_quirk;

        sdw_modify_slave_status(slave, SDW_SLAVE_ALERT);

        ret = pm_runtime_get_sync(&slave->dev);
        if (ret < 0 && ret != -EACCES) {
                dev_err(&slave->dev, "Failed to resume device: %d\n", ret);
                pm_runtime_put_noidle(&slave->dev);
                return ret;
        }

        /* Read Intstat 1, Intstat 2 and Intstat 3 registers */
        ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
        if (ret < 0) {
                dev_err(&slave->dev,
                        "SDW_SCP_INT1 read failed:%d\n", ret);
                goto io_err;
        }
        buf = ret;

        ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, buf2);
        if (ret < 0) {
                dev_err(&slave->dev,
                        "SDW_SCP_INT2/3 read failed:%d\n", ret);
                goto io_err;
        }

        if (slave->prop.is_sdca) {
                ret = sdw_read_no_pm(slave, SDW_DP0_INT);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_DP0_INT read failed:%d\n", ret);
                        goto io_err;
                }
                sdca_cascade = ret & SDW_DP0_SDCA_CASCADE;
        }

        do {
                slave_notify = false;

                /*
                 * Check parity, bus clash and Slave (impl defined)
                 * interrupt
                 */
                if (buf & SDW_SCP_INT1_PARITY) {
                        parity_check = slave->prop.scp_int1_mask & SDW_SCP_INT1_PARITY;
                        parity_quirk = !slave->first_interrupt_done &&
                                (slave->prop.quirks & SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY);

                        if (parity_check && !parity_quirk)
                                dev_err(&slave->dev, "Parity error detected\n");
                        clear |= SDW_SCP_INT1_PARITY;
                }

                if (buf & SDW_SCP_INT1_BUS_CLASH) {
                        if (slave->prop.scp_int1_mask & SDW_SCP_INT1_BUS_CLASH)
                                dev_err(&slave->dev, "Bus clash detected\n");
                        clear |= SDW_SCP_INT1_BUS_CLASH;
                }

                /*
                 * When bus clash or parity errors are detected, such errors
                 * are unlikely to be recoverable errors.
                 * TODO: In such scenario, reset bus. Make this configurable
                 * via sysfs property with bus reset being the default.
                 */

                if (buf & SDW_SCP_INT1_IMPL_DEF) {
                        if (slave->prop.scp_int1_mask & SDW_SCP_INT1_IMPL_DEF) {
                                dev_dbg(&slave->dev, "Slave impl defined interrupt\n");
                                slave_notify = true;
                        }
                        clear |= SDW_SCP_INT1_IMPL_DEF;
                }

                /* the SDCA interrupts are cleared in the codec driver .interrupt_callback() */
                if (sdca_cascade)
                        slave_notify = true;

                /* Check port 0 - 3 interrupts */
                port = buf & SDW_SCP_INT1_PORT0_3;

                /* To get port number corresponding to bits, shift it */
                port = FIELD_GET(SDW_SCP_INT1_PORT0_3, port);
                for_each_set_bit(bit, &port, 8) {
                        sdw_handle_port_interrupt(slave, bit,
                                                  &port_status[bit]);
                }

                /* Check if cascade 2 interrupt is present */
                if (buf & SDW_SCP_INT1_SCP2_CASCADE) {
                        port = buf2[0] & SDW_SCP_INTSTAT2_PORT4_10;
                        for_each_set_bit(bit, &port, 8) {
                                /* scp2 ports start from 4 */
                                port_num = bit + 3;
                                sdw_handle_port_interrupt(slave,
                                                port_num,
                                                &port_status[port_num]);
                        }
                }

                /* now check last cascade */
                if (buf2[0] & SDW_SCP_INTSTAT2_SCP3_CASCADE) {
                        port = buf2[1] & SDW_SCP_INTSTAT3_PORT11_14;
                        for_each_set_bit(bit, &port, 8) {
                                /* scp3 ports start from 11 */
                                port_num = bit + 10;
                                sdw_handle_port_interrupt(slave,
                                                port_num,
                                                &port_status[port_num]);
                        }
                }

                /* Update the Slave driver */
                if (slave_notify && slave->ops &&
                    slave->ops->interrupt_callback) {
                        slave_intr.sdca_cascade = sdca_cascade;
                        slave_intr.control_port = clear;
                        memcpy(slave_intr.port, &port_status,
                               sizeof(slave_intr.port));

                        slave->ops->interrupt_callback(slave, &slave_intr);
                }

                /* Ack interrupt */
                ret = sdw_write_no_pm(slave, SDW_SCP_INT1, clear);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_SCP_INT1 write failed:%d\n", ret);
                        goto io_err;
                }

                /* at this point all initial interrupt sources were handled */
                slave->first_interrupt_done = true;

                /*
                 * Read status again to ensure no new interrupts arrived
                 * while servicing interrupts.
                 */
                ret = sdw_read_no_pm(slave, SDW_SCP_INT1);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_SCP_INT1 recheck read failed:%d\n", ret);
                        goto io_err;
                }
                _buf = ret;

                ret = sdw_nread_no_pm(slave, SDW_SCP_INTSTAT2, 2, _buf2);
                if (ret < 0) {
                        dev_err(&slave->dev,
                                "SDW_SCP_INT2/3 recheck read failed:%d\n", ret);
                        goto io_err;
                }

                if (slave->prop.is_sdca) {
                        ret = sdw_read_no_pm(slave, SDW_DP0_INT);
                        if (ret < 0) {
                                dev_err(&slave->dev,
                                        "SDW_DP0_INT recheck read failed:%d\n", ret);
                                goto io_err;
                        }
                        sdca_cascade = ret & SDW_DP0_SDCA_CASCADE;
                }

                /*
                 * Make sure no interrupts are pending, but filter to limit loop
                 * to interrupts identified in the first status read
                 */
                buf &= _buf;
                buf2[0] &= _buf2[0];
                buf2[1] &= _buf2[1];
                stat = buf || buf2[0] || buf2[1] || sdca_cascade;

                /*
                 * Exit loop if Slave is continuously in ALERT state even
                 * after servicing the interrupt multiple times.
                 */
                count++;

                /* we can get alerts while processing so keep retrying */
        } while (stat != 0 && count < SDW_READ_INTR_CLEAR_RETRY);

        if (count == SDW_READ_INTR_CLEAR_RETRY)
                dev_warn(&slave->dev, "Reached MAX_RETRY on alert read\n");

io_err:
        pm_runtime_mark_last_busy(&slave->dev);
        pm_runtime_put_autosuspend(&slave->dev);

        return ret;
}

static int sdw_update_slave_status(struct sdw_slave *slave,
                                   enum sdw_slave_status status)
{
        unsigned long time;

        if (!slave->probed) {
                /*
                 * the slave status update is typically handled in an
                 * interrupt thread, which can race with the driver
                 * probe, e.g. when a module needs to be loaded.
                 *
                 * make sure the probe is complete before updating
                 * status.
                 */
                time = wait_for_completion_timeout(&slave->probe_complete,
                                msecs_to_jiffies(DEFAULT_PROBE_TIMEOUT));
                if (!time) {
                        dev_err(&slave->dev, "Probe not complete, timed out\n");
                        return -ETIMEDOUT;
                }
        }

        if (!slave->ops || !slave->ops->update_status)
                return 0;

        return slave->ops->update_status(slave, status);
}

/**
 * sdw_handle_slave_status() - Handle Slave status
 * @bus: SDW bus instance
 * @status: Status for all Slave(s)
 */
int sdw_handle_slave_status(struct sdw_bus *bus,
                            enum sdw_slave_status status[])
{
        enum sdw_slave_status prev_status;
        struct sdw_slave *slave;
        bool attached_initializing;
        int i, ret = 0;

        /* first check if any Slaves fell off the bus */
        for (i = 1; i <= SDW_MAX_DEVICES; i++) {
                mutex_lock(&bus->bus_lock);
                if (test_bit(i, bus->assigned) == false) {
                        mutex_unlock(&bus->bus_lock);
                        continue;
                }
                mutex_unlock(&bus->bus_lock);

                slave = sdw_get_slave(bus, i);
                if (!slave)
                        continue;

                if (status[i] == SDW_SLAVE_UNATTACHED &&
                    slave->status != SDW_SLAVE_UNATTACHED)
                        sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
        }

        if (status[0] == SDW_SLAVE_ATTACHED) {
                dev_dbg(bus->dev, "Slave attached, programming device number\n");
                ret = sdw_program_device_num(bus);
                if (ret < 0)
                        dev_err(bus->dev, "Slave attach failed: %d\n", ret);
                /*
                 * programming a device number will have side effects,
                 * so we deal with other devices at a later time
                 */
                return ret;
        }

        /* Continue to check other slave statuses */
        for (i = 1; i <= SDW_MAX_DEVICES; i++) {
                mutex_lock(&bus->bus_lock);
                if (test_bit(i, bus->assigned) == false) {
                        mutex_unlock(&bus->bus_lock);
                        continue;
                }
                mutex_unlock(&bus->bus_lock);

                slave = sdw_get_slave(bus, i);
                if (!slave)
                        continue;

                attached_initializing = false;

                switch (status[i]) {
                case SDW_SLAVE_UNATTACHED:
                        if (slave->status == SDW_SLAVE_UNATTACHED)
                                break;

                        sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
                        break;

                case SDW_SLAVE_ALERT:
                        ret = sdw_handle_slave_alerts(slave);
                        if (ret < 0)
                                dev_err(&slave->dev,
                                        "Slave %d alert handling failed: %d\n",
                                        i, ret);
                        break;

                case SDW_SLAVE_ATTACHED:
                        if (slave->status == SDW_SLAVE_ATTACHED)
                                break;

                        prev_status = slave->status;
                        sdw_modify_slave_status(slave, SDW_SLAVE_ATTACHED);

                        if (prev_status == SDW_SLAVE_ALERT)
                                break;

                        attached_initializing = true;

                        ret = sdw_initialize_slave(slave);
                        if (ret < 0)
                                dev_err(&slave->dev,
                                        "Slave %d initialization failed: %d\n",
                                        i, ret);

                        break;

                default:
                        dev_err(&slave->dev, "Invalid slave %d status:%d\n",
                                i, status[i]);
                        break;
                }

                ret = sdw_update_slave_status(slave, status[i]);
                if (ret < 0)
                        dev_err(&slave->dev,
                                "Update Slave status failed:%d\n", ret);
                if (attached_initializing) {
                        dev_dbg(&slave->dev,
                                "%s: signaling initialization completion for Slave %d\n",
                                __func__, slave->dev_num);

                        complete(&slave->initialization_complete);
                }
        }

        return ret;
}
EXPORT_SYMBOL(sdw_handle_slave_status);

void sdw_clear_slave_status(struct sdw_bus *bus, u32 request)
{
        struct sdw_slave *slave;
        int i;

        /* Check all non-zero devices */
        for (i = 1; i <= SDW_MAX_DEVICES; i++) {
                mutex_lock(&bus->bus_lock);
                if (test_bit(i, bus->assigned) == false) {
                        mutex_unlock(&bus->bus_lock);
                        continue;
                }
                mutex_unlock(&bus->bus_lock);

                slave = sdw_get_slave(bus, i);
                if (!slave)
                        continue;

                if (slave->status != SDW_SLAVE_UNATTACHED) {
                        sdw_modify_slave_status(slave, SDW_SLAVE_UNATTACHED);
                        slave->first_interrupt_done = false;
                        sdw_update_slave_status(slave, SDW_SLAVE_UNATTACHED);
                }

                /* keep track of request, used in pm_runtime resume */
                slave->unattach_request = request;
        }
}
EXPORT_SYMBOL(sdw_clear_slave_status);