ASoC/SoundWire: add SDCA helper library

drivers/soundwire/Kconfig

@@ -6,6 +6,7 @@
 menuconfig SOUNDWIRE
 	tristate "SoundWire support"
 	depends on ACPI || OF
+	depends on SND_SOC_SDCA_OPTIONAL
 	help
 	  SoundWire is a 2-Pin interface with data and clock line ratified
 	  by the MIPI Alliance. SoundWire is used for transporting data

drivers/soundwire/amd_init.c

@@ -177,7 +177,7 @@ EXPORT_SYMBOL_NS(sdw_amd_probe, SOUNDWIRE_AMD_INIT);
 void sdw_amd_exit(struct sdw_amd_ctx *ctx)
 {
 	sdw_amd_cleanup(ctx);
-	kfree(ctx->ids);
+	kfree(ctx->peripherals);
 	kfree(ctx);
 }
 EXPORT_SYMBOL_NS(sdw_amd_exit, SOUNDWIRE_AMD_INIT);
@@ -204,19 +204,19 @@ int sdw_amd_get_slave_info(struct sdw_amd_ctx *ctx)
 			num_slaves++;
 	}
 
-	ctx->ids = kcalloc(num_slaves, sizeof(*ctx->ids), GFP_KERNEL);
-	if (!ctx->ids)
+	ctx->peripherals = kmalloc(struct_size(ctx->peripherals, array, num_slaves),
+				   GFP_KERNEL);
+	if (!ctx->peripherals)
 		return -ENOMEM;
-	ctx->num_slaves = num_slaves;
+	ctx->peripherals->num_peripherals = num_slaves;
 	for (index = 0; index < ctx->count; index++) {
 		if (!(ctx->link_mask & BIT(index)))
 			continue;
 		amd_manager = dev_get_drvdata(&ctx->pdev[index]->dev);
 		if (amd_manager) {
 			bus = &amd_manager->bus;
 			list_for_each_entry(slave, &bus->slaves, node) {
-				ctx->ids[i].id = slave->id;
-				ctx->ids[i].link_id = bus->link_id;
+				ctx->peripherals->array[i] = slave;
 				i++;
 			}
 		}

drivers/soundwire/intel_init.c

@@ -252,17 +252,16 @@ static struct sdw_intel_ctx
 			num_slaves++;
 	}
 
-	ctx->ids = kcalloc(num_slaves, sizeof(*ctx->ids), GFP_KERNEL);
-	if (!ctx->ids)
+	ctx->peripherals = kmalloc(struct_size(ctx->peripherals, array, num_slaves),
+				   GFP_KERNEL);
+	if (!ctx->peripherals)
 		goto err;
-
-	ctx->num_slaves = num_slaves;
+	ctx->peripherals->num_peripherals = num_slaves;
 	i = 0;
 	list_for_each_entry(link, &ctx->link_list, list) {
 		bus = &link->cdns->bus;
 		list_for_each_entry(slave, &bus->slaves, node) {
-			ctx->ids[i].id = slave->id;
-			ctx->ids[i].link_id = bus->link_id;
+			ctx->peripherals->array[i] = slave;
 			i++;
 		}
 	}
@@ -371,7 +370,7 @@ void sdw_intel_exit(struct sdw_intel_ctx *ctx)
 	}
 
 	sdw_intel_cleanup(ctx);
-	kfree(ctx->ids);
+	kfree(ctx->peripherals);
 	kfree(ctx->ldev);
 	kfree(ctx);
 }

drivers/soundwire/slave.c

@@ -5,6 +5,7 @@
 #include <linux/of.h>
 #include <linux/soundwire/sdw.h>
 #include <linux/soundwire/sdw_type.h>
+#include <sound/sdca.h>
 #include "bus.h"
 #include "sysfs_local.h"
 
@@ -70,6 +71,17 @@ int sdw_slave_add(struct sdw_bus *bus,
 	list_add_tail(&slave->node, &bus->slaves);
 	mutex_unlock(&bus->bus_lock);
 
+	/*
+	 * The Soundwire driver probe may optionally register SDCA
+	 * sub-devices, one per Function. This means the information
+	 * on the SDCA revision and the number/type of Functions need
+	 * to be extracted from platform firmware before the SoundWire
+	 * driver probe, and as a consequence before the SoundWire
+	 * device_register() below.
+	 */
+	sdca_lookup_interface_revision(slave);
+	sdca_lookup_functions(slave);
+
 	ret = device_register(&slave->dev);
 	if (ret) {
 		dev_err(bus->dev, "Failed to add slave: ret %d\n", ret);
@@ -259,3 +271,5 @@ int sdw_of_find_slaves(struct sdw_bus *bus)
 
 	return 0;
 }
+
+MODULE_IMPORT_NS(SND_SOC_SDCA);

include/linux/soundwire/sdw.h

@@ -10,6 +10,7 @@
 #include <linux/irqdomain.h>
 #include <linux/mod_devicetable.h>
 #include <linux/bitfield.h>
+#include <sound/sdca.h>
 
 struct sdw_bus;
 struct sdw_slave;
@@ -488,9 +489,9 @@ struct sdw_slave_id {
 	__u8 sdw_version:4;
 };
 
-struct sdw_extended_slave_id {
-	int link_id;
-	struct sdw_slave_id id;
+struct sdw_peripherals {
+	int num_peripherals;
+	struct sdw_slave *array[];
 };
 
 /*
@@ -663,6 +664,7 @@ struct sdw_slave_ops {
  * @is_mockup_device: status flag used to squelch errors in the command/control
  * protocol for SoundWire mockup devices
  * @sdw_dev_lock: mutex used to protect callbacks/remove races
+ * @sdca_data: structure containing all device data for SDCA helpers
  */
 struct sdw_slave {
 	struct sdw_slave_id id;
@@ -686,6 +688,7 @@ struct sdw_slave {
 	bool first_interrupt_done;
 	bool is_mockup_device;
 	struct mutex sdw_dev_lock; /* protect callbacks/remove races */
+	struct sdca_device_data sdca_data;
 };
 
 #define dev_to_sdw_dev(_dev) container_of(_dev, struct sdw_slave, dev)

include/linux/soundwire/sdw_amd.h

@@ -115,19 +115,16 @@ struct sdw_amd_acpi_info {
  * struct sdw_amd_ctx - context allocated by the controller driver probe
  *
  * @count: link count
- * @num_slaves: total number of devices exposed across all enabled links
  * @link_mask: bit-wise mask listing SoundWire links reported by the
  * Controller
- * @ids: array of slave_id, representing Slaves exposed across all enabled
- * links
  * @pdev: platform device structure
+ * @peripherals: array representing Peripherals exposed across all enabled links
  */
 struct sdw_amd_ctx {
 	int count;
-	int num_slaves;
 	u32 link_mask;
-	struct sdw_extended_slave_id *ids;
 	struct platform_device *pdev[AMD_SDW_MAX_MANAGER_COUNT];
+	struct sdw_peripherals *peripherals;
 };
 
 /**

include/linux/soundwire/sdw_intel.h

@@ -286,31 +286,28 @@ struct hdac_bus;
  * hardware capabilities after all power dependencies are settled.
  * @link_mask: bit-wise mask listing SoundWire links reported by the
  * Controller
- * @num_slaves: total number of devices exposed across all enabled links
  * @handle: ACPI parent handle
  * @ldev: information for each link (controller-specific and kept
  * opaque here)
- * @ids: array of slave_id, representing Slaves exposed across all enabled
- * links
  * @link_list: list to handle interrupts across all links
  * @shim_lock: mutex to handle concurrent rmw access to shared SHIM registers.
  * @shim_mask: flags to track initialization of SHIM shared registers
  * @shim_base: sdw shim base.
  * @alh_base: sdw alh base.
+ * @peripherals: array representing Peripherals exposed across all enabled links
  */
 struct sdw_intel_ctx {
 	int count;
 	void __iomem *mmio_base;
 	u32 link_mask;
-	int num_slaves;
 	acpi_handle handle;
 	struct sdw_intel_link_dev **ldev;
-	struct sdw_extended_slave_id *ids;
 	struct list_head link_list;
 	struct mutex shim_lock; /* lock for access to shared SHIM registers */
 	u32 shim_mask;
 	u32 shim_base;
 	u32 alh_base;
+	struct sdw_peripherals *peripherals;
 };
 
 /**

include/sound/sdca.h

@@ -0,0 +1,162 @@
+/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) */
+/*
+ * The MIPI SDCA specification is available for public downloads at
+ * https://www.mipi.org/mipi-sdca-v1-0-download
+ *
+ * Copyright(c) 2024 Intel Corporation
+ */
+
+#ifndef __SDCA_H__
+#define __SDCA_H__
+
+struct sdw_slave;
+
+#define SDCA_MAX_INTERRUPTS 31 /* the last bit is reserved for future extensions */
+
+/**
+ * struct sdca_interrupt_source - interface between interrupt source and
+ * SoundWire SDCA interrupt handler
+ *
+ * @index: SDCA interrupt number in [0, SDCA_MAX_INTERRUPTS - 1]
+ * @context: source-specific information, used by @callback
+ * @callback: provided by interrupt source for source-specific handling.
+ */
+struct sdca_interrupt_source {
+	int index;
+	void *context;
+	void (*callback)(void *context);
+};
+
+/**
+ * struct sdca_interrupt_info - Peripheral device-level information
+ * used for interrupt handler
+ *
+ * @sources: array of pointers, addressed with an interrupt index
+ * matching @registered_source_mask bits.
+ * @irqs_lock: mutex protecting concurrent access to @sources,
+ * @registered_source_mask and reventing SDCA interrupts from being disabled
+ * on suspend while being handled.
+ * @enabled_interrupt_mask: mask indicating which interrupts from @registered_source_mask
+ * are currently enabled.
+ * @detected_interrupt_mask: bitfields set in interrupt handler, and accessible
+ * in deferred processing.
+ * @supported_hw_register_mask: Up to 4 registers may be implemented
+ */
+struct sdca_interrupt_info {
+	struct sdca_interrupt_source *sources[SDCA_MAX_INTERRUPTS];
+	struct mutex irqs_lock; /* protects SDCA interrupts */
+	u32 registered_source_mask;
+	u32 enabled_interrupt_mask;
+	u32 detected_interrupt_mask;
+	int supported_hw_register_mask;
+};
+
+#define SDCA_MAX_FUNCTION_COUNT 8
+
+/**
+ * sdca_device_desc - short descriptor for an SDCA Function
+ * @adr: ACPI address (used for SDCA register access)
+ * @type: Function topology type
+ * @name: human-readable string
+ */
+struct sdca_function_desc {
+	u64 adr;
+	u32 type;
+	const char *name;
+};
+
+/**
+ * sdca_device_data - structure containing all SDCA related information
+ * @sdca_interface_revision: value read from _DSD property, mainly to check
+ * for changes between silicon versions
+ * @num_functions: total number of supported SDCA functions. Invalid/unsupported
+ * functions will be skipped.
+ * @sdca_func: array of function descriptors
+ * @interrupt_info: device-level interrupt configuration/handling
+ */
+struct sdca_device_data {
+	u32 interface_revision;
+	int num_functions;
+	struct sdca_function_desc sdca_func[SDCA_MAX_FUNCTION_COUNT];
+	struct sdca_interrupt_info *interrupt_info;
+};
+
+enum sdca_quirk {
+	SDCA_QUIRKS_RT712_VB,
+};
+
+#if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SND_SOC_SDCA)
+
+void sdca_lookup_functions(struct sdw_slave *slave);
+void sdca_lookup_interface_revision(struct sdw_slave *slave);
+bool sdca_device_quirk_match(struct sdw_slave *slave, enum sdca_quirk quirk);
+
+#else
+
+static inline void sdca_lookup_functions(struct sdw_slave *slave) {}
+static inline void sdca_lookup_interface_revision(struct sdw_slave *slave) {}
+static inline bool sdca_device_quirk_match(struct sdw_slave *slave, enum sdca_quirk quirk)
+{
+	return false;
+}
+
+#endif
+
+#if IS_ENABLED(CONFIG_SND_SOC_SDCA_IRQ_HANDLER)
+
+int sdca_interrupt_info_alloc(struct sdw_slave *slave);
+void sdca_interrupt_info_release(struct sdw_slave *slave);
+int sdca_interrupt_info_reset(struct sdw_slave *slave);
+int sdca_interrupt_initialize(struct sdw_slave *slave,
+			      int supported_hw_register_mask);
+int sdca_interrupt_register_source(struct sdw_slave *slave,
+				   struct sdca_interrupt_source *source);
+int sdca_interrupt_enable(struct sdw_slave *slave,
+			  u32 source_mask,
+			  bool enable);
+void sdca_interrupt_clear_history(struct sdw_slave *slave, u32 preserve_mask);
+int sdca_interrupt_handler(struct sdw_slave *slave);
+
+#else
+
+static inline int sdca_interrupt_info_alloc(struct sdw_slave *slave)
+{
+	return 0;
+}
+
+static inline void sdca_interrupt_info_release(struct sdw_slave *slave) {}
+
+static inline int sdca_interrupt_info_reset(struct sdw_slave *slave)
+{
+	return 0;
+}
+
+static inline int sdca_interrupt_initialize(struct sdw_slave *slave,
+					    int supported_hw_register_mask)
+{
+	return 0;
+}
+
+static inline int sdca_interrupt_register_source(struct sdw_slave *slave,
+						 struct sdca_interrupt_source *source)
+{
+	return 0;
+}
+
+static inline int sdca_interrupt_enable(struct sdw_slave *slave,
+					u32 source_mask,
+					bool enable)
+{
+	return 0;
+}
+
+static inline void sdca_interrupt_clear_history(struct sdw_slave *slave, u32 preserve_mask) {}
+
+static inline int sdca_interrupt_handler(struct sdw_slave *slave)
+{
+	return 0;
+}
+
+#endif /* IS_ENABLED(CONFIG_SND_SOC_SDCA_IRQ_HANDLER) */
+
+#endif