ASoC/soundwire: implement generic api for scanning amd soundwire controller

Implement generic function for scanning SoundWire controller.
Same function will be used for legacy and sof stack for AMD platforms.
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://msgid.link/r/20240129055147.1493853-2-Vijendar.Mukunda@amd.comSigned-off-by: Mark Brown <broonie@kernel.org>

include/linux/soundwire/sdw_amd.h

@@ -6,6 +6,7 @@
 #ifndef __SDW_AMD_H
 #define __SDW_AMD_H
 
+#include <linux/acpi.h>
 #include <linux/soundwire/sdw.h>
 
 /* AMD pm_runtime quirk definitions */
@@ -106,4 +107,18 @@ struct amd_sdw_manager {
 
 	struct sdw_amd_dai_runtime **dai_runtime_array;
 };
+
+/**
+ * struct sdw_amd_acpi_info - Soundwire AMD information found in ACPI tables
+ * @handle: ACPI controller handle
+ * @count: maximum no of soundwire manager links supported on AMD platform.
+ * @link_mask: bit-wise mask listing links enabled by BIOS menu
+ */
+struct sdw_amd_acpi_info {
+	acpi_handle handle;
+	int count;
+	u32 link_mask;
+};
+
+int amd_sdw_scan_controller(struct sdw_amd_acpi_info *info);
 #endif

sound/soc/amd/acp/Kconfig

@@ -101,6 +101,13 @@ config SND_SOC_AMD_MACH_COMMON
 	help
 	  This option enables common Machine driver module for ACP.
 
+config SND_AMD_SOUNDWIRE_ACPI
+	tristate "AMD SoundWire ACPI Support"
+	depends on ACPI
+	help
+	  This options enables ACPI helper functions for SoundWire
+	  interface for AMD platforms.
+
 config SND_SOC_AMD_LEGACY_MACH
 	tristate "AMD Legacy Machine Driver Support"
 	depends on X86 && PCI && I2C

sound/soc/amd/acp/Makefile

@@ -10,6 +10,7 @@ snd-acp-i2s-objs     := acp-i2s.o
 snd-acp-pdm-objs     := acp-pdm.o
 snd-acp-legacy-common-objs   := acp-legacy-common.o
 snd-acp-pci-objs     := acp-pci.o
+snd-amd-sdw-acpi-objs := amd-sdw-acpi.o
 
 #platform specific driver
 snd-acp-renoir-objs     := acp-renoir.o
@@ -33,6 +34,7 @@ obj-$(CONFIG_SND_AMD_ASOC_REMBRANDT) += snd-acp-rembrandt.o
 obj-$(CONFIG_SND_AMD_ASOC_ACP63) += snd-acp63.o
 obj-$(CONFIG_SND_AMD_ASOC_ACP70) += snd-acp70.o
 
+obj-$(CONFIG_SND_AMD_SOUNDWIRE_ACPI) += snd-amd-sdw-acpi.o
 obj-$(CONFIG_SND_SOC_AMD_MACH_COMMON) += snd-acp-mach.o
 obj-$(CONFIG_SND_SOC_AMD_LEGACY_MACH) += snd-acp-legacy-mach.o
 obj-$(CONFIG_SND_SOC_AMD_SOF_MACH) += snd-acp-sof-mach.o

sound/soc/amd/acp/amd-sdw-acpi.c

+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license. When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2023 Advanced Micro Devices, Inc. All rights reserved.
+//
+// Authors: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
+
+/*
+ * SDW AMD ACPI scan helper function
+ */
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fwnode.h>
+#include <linux/module.h>
+#include <linux/soundwire/sdw_amd.h>
+#include <linux/string.h>
+
+int amd_sdw_scan_controller(struct sdw_amd_acpi_info *info)
+{
+	struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);
+	u32 sdw_bitmap = 0;
+	u8 count = 0;
+	int ret;
+
+	if (!adev)
+		return -EINVAL;
+
+	/* Found controller, find links supported */
+	ret = fwnode_property_read_u32_array(acpi_fwnode_handle(adev),
+					     "mipi-sdw-manager-list", &sdw_bitmap, 1);
+	if (ret) {
+		dev_err(&adev->dev,
+			"Failed to read mipi-sdw-manager-list: %d\n", ret);
+		return -EINVAL;
+	}
+	count = hweight32(sdw_bitmap);
+	/* Check count is within bounds */
+	if (count > info->count) {
+		dev_err(&adev->dev, "Manager count %d exceeds max %d\n",
+			count, info->count);
+		return -EINVAL;
+	}
+
+	if (!count) {
+		dev_dbg(&adev->dev, "No SoundWire Managers detected\n");
+		return -EINVAL;
+	}
+	dev_dbg(&adev->dev, "ACPI reports %d SoundWire Manager devices\n", count);
+	info->link_mask = sdw_bitmap;
+	return 0;
+}
+EXPORT_SYMBOL_NS(amd_sdw_scan_controller, SND_AMD_SOUNDWIRE_ACPI);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("AMD SoundWire ACPI helpers");