amd-sdw-acpi.c

 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(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(acpi_fwnode_handle(adev),
37					     "mipi-sdw-manager-list", &sdw_bitmap, 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");