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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/sound/soc/amd/acp/amd-sdw-acpi.c
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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)

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//

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// This file is provided under a dual BSD/GPLv2 license. When using or

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// redistributing this file, you may do so under either license.

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//

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// Copyright(c) 2023 Advanced Micro Devices, Inc. All rights reserved.

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//

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// Authors: Vijendar Mukunda <[email protected]>

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/*

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 * SDW AMD ACPI scan helper function

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 */

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#include <linux/acpi.h>

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#include <linux/bits.h>

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#include <linux/bitfield.h>

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#include <linux/device.h>

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#include <linux/errno.h>

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#include <linux/export.h>

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#include <linux/fwnode.h>

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#include <linux/module.h>

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#include <linux/soundwire/sdw_amd.h>

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#include <linux/string.h>

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int amd_sdw_scan_controller(struct sdw_amd_acpi_info *info)

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{

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	struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);

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	u32 sdw_bitmap = 0;

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	u8 count = 0;

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	int ret;

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	if (!adev)

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		return -EINVAL;

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	/* Found controller, find links supported */

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	ret = fwnode_property_read_u32_array(acpi_fwnode_handle(adev),

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					     "mipi-sdw-manager-list", &sdw_bitmap, 1);

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	if (ret) {

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		dev_err(&adev->dev,

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			"Failed to read mipi-sdw-manager-list: %d\n", ret);

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		return -EINVAL;

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	}

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	count = hweight32(sdw_bitmap);

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	/* Check count is within bounds */

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	if (count > info->count) {

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		dev_err(&adev->dev, "Manager count %d exceeds max %d\n",

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			count, info->count);

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		return -EINVAL;

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	}

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	if (!count) {

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		dev_dbg(&adev->dev, "No SoundWire Managers detected\n");

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		return -EINVAL;

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	}

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	dev_dbg(&adev->dev, "ACPI reports %d SoundWire Manager devices\n", count);

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	info->link_mask = sdw_bitmap;

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	return 0;

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}

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EXPORT_SYMBOL_NS(amd_sdw_scan_controller, "SND_AMD_SOUNDWIRE_ACPI");

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MODULE_LICENSE("Dual BSD/GPL");

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MODULE_DESCRIPTION("AMD SoundWire ACPI helpers");

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