Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1042 insertions, 0 deletions

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
new file mode 100644
index 000000000..0089b606b
--- /dev/null
+++ b/drivers/soundwire/bus.c
@@ -0,0 +1,1042 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2015-17 Intel Corporation.
+
+#include <linux/acpi.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"
+
+/**
+ * sdw_add_bus_master() - add a bus Master instance
+ * @bus: bus instance
+ *
+ * Initializes the bus instance, read properties and create child
+ * devices.
+ */
+int sdw_add_bus_master(struct sdw_bus *bus)
+{
+	struct sdw_master_prop *prop = NULL;
+	int ret;
+
+	if (!bus->dev) {
+		pr_err("SoundWire bus has no device");
+		return -ENODEV;
+	}
+
+	if (!bus->ops) {
+		dev_err(bus->dev, "SoundWire Bus ops are not set");
+		return -EINVAL;
+	}
+
+	mutex_init(&bus->msg_lock);
+	mutex_init(&bus->bus_lock);
+	INIT_LIST_HEAD(&bus->slaves);
+	INIT_LIST_HEAD(&bus->m_rt_list);
+
+	if (bus->ops->read_prop) {
+		ret = bus->ops->read_prop(bus);
+		if (ret < 0) {
+			dev_err(bus->dev, "Bus read properties failed:%d", ret);
+			return ret;
+		}
+	}
+
+	/*
+	 * Device numbers in SoundWire are 0 thru 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
+		ret = -ENOTSUPP; /* No ACPI/DT so error out */
+
+	if (ret) {
+		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_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_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_add_bus_master);
+
+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;
+
+	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_delete_bus_master() - delete the bus master instance
+ * @bus: bus to be deleted
+ *
+ * Remove the instance, delete the child devices.
+ */
+void sdw_delete_bus_master(struct sdw_bus *bus)
+{
+	device_for_each_child(bus->dev, NULL, sdw_delete_slave);
+}
+EXPORT_SYMBOL(sdw_delete_bus_master);
+
+/*
+ * 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;
+}
+
+/**
+ * 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 = do_transfer(bus, msg);
+	if (ret != 0 && ret != -ENODATA)
+		dev_err(bus->dev, "trf on Slave %d failed:%d\n",
+				msg->dev_num, ret);
+
+	if (msg->page)
+		sdw_reset_page(bus, msg->dev_num);
+
+	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;
+	msg->ssp_sync = false;
+	msg->page = false;
+
+	if (addr < SDW_REG_NO_PAGE) { /* no paging area */
+		return 0;
+	} else 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 thru 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;
+	} else if (!slave->prop.paging_support) {
+		dev_err(&slave->dev,
+			"address %x needs paging but no support", addr);
+		return -EINVAL;
+	}
+
+	msg->addr_page1 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE1_MASK));
+	msg->addr_page2 = (addr >> SDW_REG_SHIFT(SDW_SCP_ADDRPAGE2_MASK));
+	msg->addr |= BIT(15);
+	msg->page = true;
+
+	return 0;
+}
+
+/**
+ * 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)
+{
+	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 = pm_runtime_get_sync(slave->bus->dev);
+	if (ret < 0)
+		return ret;
+
+	ret = sdw_transfer(slave->bus, &msg);
+	pm_runtime_put(slave->bus->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 read
+ */
+int sdw_nwrite(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_WRITE, val);
+	if (ret < 0)
+		return ret;
+
+	ret = pm_runtime_get_sync(slave->bus->dev);
+	if (ret < 0)
+		return ret;
+
+	ret = sdw_transfer(slave->bus, &msg);
+	pm_runtime_put(slave->bus->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;
+	else
+		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 = NULL;
+
+	list_for_each_entry(slave, &bus->slaves, node) {
+		if (slave->dev_num == i)
+			return slave;
+	}
+
+	return NULL;
+}
+
+static int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id)
+{
+
+	if ((slave->id.unique_id != id.unique_id) ||
+	    (slave->id.mfg_id != id.mfg_id) ||
+	    (slave->id.part_id != id.part_id) ||
+	    (slave->id.class_id != id.class_id))
+		return -ENODEV;
+
+	return 0;
+}
+
+/* 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)
+{
+	int ret, dev_num;
+
+	/* check first if device number is assigned, if so reuse that */
+	if (!slave->dev_num) {
+		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(slave->bus->dev, "Get dev_num failed: %d",
+								dev_num);
+			return dev_num;
+		}
+	} else {
+		dev_info(slave->bus->dev,
+				"Slave already registered dev_num:%d",
+				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(slave, SDW_SCP_DEVNUMBER, dev_num);
+	if (ret < 0) {
+		dev_err(&slave->dev, "Program device_num failed: %d", ret);
+		return ret;
+	}
+
+	/* After xfer of msg, restore dev_num */
+	slave->dev_num = dev_num;
+
+	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", addr);
+
+	/*
+	 * Spec definition
+	 *   Register		Bit	Contents
+	 *   DevId_0 [7:4]	47:44	sdw_version
+	 *   DevId_0 [3:0]	43:40	unique_id
+	 *   DevId_1		39:32	mfg_id [15:8]
+	 *   DevId_2		31:24	mfg_id [7:0]
+	 *   DevId_3		23:16	part_id [15:8]
+	 *   DevId_4		15:08	part_id [7:0]
+	 *   DevId_5		07:00	class_id
+	 */
+	id->sdw_version = (addr >> 44) & GENMASK(3, 0);
+	id->unique_id = (addr >> 40) & GENMASK(3, 0);
+	id->mfg_id = (addr >> 24) & GENMASK(15, 0);
+	id->part_id = (addr >> 8) & GENMASK(15, 0);
+	id->class_id = addr & GENMASK(7, 0);
+
+	dev_dbg(bus->dev,
+		"SDW Slave class_id %x, part_id %x, mfg_id %x, unique_id %x, version %x",
+				id->class_id, id->part_id, id->mfg_id,
+				id->unique_id, id->sdw_version);
+
+}
+
+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 */
+			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) {
+					dev_err(slave->bus->dev,
+						"Assign dev_num failed:%d",
+						ret);
+					return ret;
+				}
+
+				break;
+			}
+		}
+
+		if (found == false) {
+			/* TODO: Park this device in Group 13 */
+			dev_err(bus->dev, "Slave Entry not found");
+		}
+
+		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)
+{
+	mutex_lock(&slave->bus->bus_lock);
+	slave->status = status;
+	mutex_unlock(&slave->bus->bus_lock);
+}
+
+int sdw_configure_dpn_intr(struct sdw_slave *slave,
+			int port, bool enable, int mask)
+{
+	u32 addr;
+	int ret;
+	u8 val = 0;
+
+	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->bus->dev,
+				"SDW_DPN_INTMASK write failed:%d", val);
+
+	return ret;
+}
+
+static int sdw_initialize_slave(struct sdw_slave *slave)
+{
+	struct sdw_slave_prop *prop = &slave->prop;
+	int ret;
+	u8 val;
+
+	/*
+	 * Set bus clash, parity and SCP implementation
+	 * defined interrupt mask
+	 * TODO: Read implementation defined interrupt mask
+	 * from Slave property
+	 */
+	val = SDW_SCP_INT1_IMPL_DEF | SDW_SCP_INT1_BUS_CLASH |
+					SDW_SCP_INT1_PARITY;
+
+	/* Enable SCP interrupts */
+	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
+	if (ret < 0) {
+		dev_err(slave->bus->dev,
+				"SDW_SCP_INTMASK1 write failed:%d", 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->device_interrupts;
+	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
+
+	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
+	if (ret < 0) {
+		dev_err(slave->bus->dev,
+				"SDW_DP0_INTMASK read failed:%d", ret);
+		return val;
+	}
+
+	return 0;
+}
+
+static int sdw_handle_dp0_interrupt(struct sdw_slave *slave, u8 *slave_status)
+{
+	u8 clear = 0, impl_int_mask;
+	int status, status2, ret, count = 0;
+
+	status = sdw_read(slave, SDW_DP0_INT);
+	if (status < 0) {
+		dev_err(slave->bus->dev,
+				"SDW_DP0_INT read failed:%d", status);
+		return status;
+	}
+
+	do {
+
+		if (status & SDW_DP0_INT_TEST_FAIL) {
+			dev_err(&slave->dev, "Test fail for port 0");
+			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");
+			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 interrupt */
+		ret = sdw_write(slave, SDW_DP0_INT, clear);
+		if (ret < 0) {
+			dev_err(slave->bus->dev,
+				"SDW_DP0_INT write failed:%d", ret);
+			return ret;
+		}
+
+		/* Read DP0 interrupt again */
+		status2 = sdw_read(slave, SDW_DP0_INT);
+		if (status2 < 0) {
+			dev_err(slave->bus->dev,
+				"SDW_DP0_INT read failed:%d", status2);
+			return status2;
+		}
+		status &= status2;
+
+		count++;
+
+		/* we can get alerts while processing so keep retrying */
+	} while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY);
+
+	if (count == SDW_READ_INTR_CLEAR_RETRY)
+		dev_warn(slave->bus->dev, "Reached MAX_RETRY on DP0 read");
+
+	return ret;
+}
+
+static int sdw_handle_port_interrupt(struct sdw_slave *slave,
+		int port, u8 *slave_status)
+{
+	u8 clear = 0, 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(slave, addr);
+	if (status < 0) {
+		dev_err(slave->bus->dev,
+				"SDW_DPN_INT read failed:%d", status);
+
+		return status;
+	}
+
+	do {
+
+		if (status & SDW_DPN_INT_TEST_FAIL) {
+			dev_err(&slave->dev, "Test fail for port:%d", 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 */
+		ret = sdw_write(slave, addr, clear);
+		if (ret < 0) {
+			dev_err(slave->bus->dev,
+					"SDW_DPN_INT write failed:%d", ret);
+			return ret;
+		}
+
+		/* Read DPN interrupt again */
+		status2 = sdw_read(slave, addr);
+		if (status2 < 0) {
+			dev_err(slave->bus->dev,
+					"SDW_DPN_INT read failed:%d", status2);
+			return status2;
+		}
+		status &= status2;
+
+		count++;
+
+		/* we can get alerts while processing so keep retrying */
+	} while (status != 0 && count < SDW_READ_INTR_CLEAR_RETRY);
+
+	if (count == SDW_READ_INTR_CLEAR_RETRY)
+		dev_warn(slave->bus->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 = false;
+	u8 buf, buf2[2], _buf, _buf2[2];
+
+	sdw_modify_slave_status(slave, SDW_SLAVE_ALERT);
+
+	/* Read Instat 1, Instat 2 and Instat 3 registers */
+	buf = ret = sdw_read(slave, SDW_SCP_INT1);
+	if (ret < 0) {
+		dev_err(slave->bus->dev,
+					"SDW_SCP_INT1 read failed:%d", ret);
+		return ret;
+	}
+
+	ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, buf2);
+	if (ret < 0) {
+		dev_err(slave->bus->dev,
+					"SDW_SCP_INT2/3 read failed:%d", ret);
+		return ret;
+	}
+
+	do {
+		/*
+		 * Check parity, bus clash and Slave (impl defined)
+		 * interrupt
+		 */
+		if (buf & SDW_SCP_INT1_PARITY) {
+			dev_err(&slave->dev, "Parity error detected");
+			clear |= SDW_SCP_INT1_PARITY;
+		}
+
+		if (buf & SDW_SCP_INT1_BUS_CLASH) {
+			dev_err(&slave->dev, "Bus clash error detected");
+			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) {
+			dev_dbg(&slave->dev, "Slave impl defined interrupt\n");
+			clear |= SDW_SCP_INT1_IMPL_DEF;
+			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 = port >> SDW_REG_SHIFT(SDW_SCP_INT1_PORT0_3);
+		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.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(slave, SDW_SCP_INT1, clear);
+		if (ret < 0) {
+			dev_err(slave->bus->dev,
+					"SDW_SCP_INT1 write failed:%d", ret);
+			return ret;
+		}
+
+		/*
+		 * Read status again to ensure no new interrupts arrived
+		 * while servicing interrupts.
+		 */
+		_buf = ret = sdw_read(slave, SDW_SCP_INT1);
+		if (ret < 0) {
+			dev_err(slave->bus->dev,
+					"SDW_SCP_INT1 read failed:%d", ret);
+			return ret;
+		}
+
+		ret = sdw_nread(slave, SDW_SCP_INTSTAT2, 2, _buf2);
+		if (ret < 0) {
+			dev_err(slave->bus->dev,
+					"SDW_SCP_INT2/3 read failed:%d", ret);
+			return ret;
+		}
+
+		/* Make sure no interrupts are pending */
+		buf &= _buf;
+		buf2[0] &= _buf2[0];
+		buf2[1] &= _buf2[1];
+		stat = buf || buf2[0] || buf2[1];
+
+		/*
+		 * 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->bus->dev, "Reached MAX_RETRY on alert read");
+
+	return ret;
+}
+
+static int sdw_update_slave_status(struct sdw_slave *slave,
+				enum sdw_slave_status status)
+{
+	if ((slave->ops) && (slave->ops->update_status))
+		return slave->ops->update_status(slave, status);
+
+	return 0;
+}
+
+/**
+ * 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;
+	int i, ret = 0;
+
+	if (status[0] == SDW_SLAVE_ATTACHED) {
+		ret = sdw_program_device_num(bus);
+		if (ret)
+			dev_err(bus->dev, "Slave attach failed: %d", 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;
+
+		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)
+				dev_err(bus->dev,
+					"Slave %d alert handling failed: %d",
+					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;
+
+			ret = sdw_initialize_slave(slave);
+			if (ret)
+				dev_err(bus->dev,
+					"Slave %d initialization failed: %d",
+					i, ret);
+
+			break;
+
+		default:
+			dev_err(bus->dev, "Invalid slave %d status:%d",
+							i, status[i]);
+			break;
+		}
+
+		ret = sdw_update_slave_status(slave, status[i]);
+		if (ret)
+			dev_err(slave->bus->dev,
+				"Update Slave status failed:%d", ret);
+
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(sdw_handle_slave_status);