1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
2//
3// This file is provided under a dual BSD/GPLv2 license. When using or
4// redistributing this file, you may do so under either license.
5//
6// Copyright(c) 2023 Advanced Micro Devices, Inc. All rights reserved.
7//
8// Authors: Vijendar Mukunda <Vijendar.Mukunda@amd.com>
9
10/*
11 * SDW AMD ACPI scan helper function
12 */
13
14#include <linux/acpi.h>
15#include <linux/bits.h>
16#include <linux/bitfield.h>
17#include <linux/device.h>
18#include <linux/errno.h>
19#include <linux/export.h>
20#include <linux/module.h>
21#include <linux/property.h>
22#include <linux/soundwire/sdw_amd.h>
23#include <linux/string.h>
24
25int amd_sdw_scan_controller(struct sdw_amd_acpi_info *info)
26{
27 struct acpi_device *adev = acpi_fetch_acpi_dev(handle: info->handle);
28 u32 sdw_bitmap = 0;
29 u8 count = 0;
30 int ret;
31
32 if (!adev)
33 return -EINVAL;
34
35 /* Found controller, find links supported */
36 ret = fwnode_property_read_u32_array(fwnode: acpi_fwnode_handle(adev),
37 propname: "mipi-sdw-manager-list", val: &sdw_bitmap, nval: 1);
38 if (ret) {
39 dev_err(&adev->dev,
40 "Failed to read mipi-sdw-manager-list: %d\n", ret);
41 return -EINVAL;
42 }
43 count = hweight32(sdw_bitmap);
44 /* Check count is within bounds */
45 if (count > info->count) {
46 dev_err(&adev->dev, "Manager count %d exceeds max %d\n",
47 count, info->count);
48 return -EINVAL;
49 }
50
51 if (!count) {
52 dev_dbg(&adev->dev, "No SoundWire Managers detected\n");
53 return -EINVAL;
54 }
55 dev_dbg(&adev->dev, "ACPI reports %d SoundWire Manager devices\n", count);
56 info->link_mask = sdw_bitmap;
57 return 0;
58}
59EXPORT_SYMBOL_NS(amd_sdw_scan_controller, "SND_AMD_SOUNDWIRE_ACPI");
60
61MODULE_LICENSE("Dual BSD/GPL");
62MODULE_DESCRIPTION("AMD SoundWire ACPI helpers");
63

source code of linux/sound/soc/amd/acp/amd-sdw-acpi.c