soundwire: Add Master registration

A Master adds a SoundWire bus instance which scans the firmware
provided for device description.

In this patch we scan ACPI namespaces and create SoundWire
Slave devices based on ACPI description

Signed-off-by: Sanyog Kale <sanyog.r.kale@intel.com>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Acked-By: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 124 insertions, 0 deletions

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
new file mode 100644
index 000000000000..bc72c3d58bbf
--- /dev/null
+++ b/drivers/soundwire/bus.c
@@ -0,0 +1,124 @@
+// 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/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)
+{
+	int ret;
+
+	if (!bus->dev) {
+		pr_err("SoundWire bus has no device");
+		return -ENODEV;
+	}
+
+	mutex_init(&bus->bus_lock);
+	INIT_LIST_HEAD(&bus->slaves);
+
+	/*
+	 * 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;
+	}
+
+	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);
+
+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);
+
+}