text: // 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) {
  			dev_warn(&slave->dev, "Slave %d state check1: UNATTACHED, status was %d\n",
  				 i, slave->status);
  			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;
  
  			dev_warn(&slave->dev, "Slave %d state check2: UNATTACHED, status was %d\n",
  				 i, slave->status);
  
  			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);
  