1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2// Copyright(c) 2015-2021 Intel Corporation.
3
4/*
5 * SDW Intel ACPI scan helpers
6 */
7
8#include <linux/acpi.h>
9#include <linux/bits.h>
10#include <linux/bitfield.h>
11#include <linux/device.h>
12#include <linux/errno.h>
13#include <linux/export.h>
14#include <linux/module.h>
15#include <linux/property.h>
16#include <linux/soundwire/sdw_intel.h>
17#include <linux/string.h>
18
19#define SDW_LINK_TYPE 4 /* from Intel ACPI documentation */
20
21static int ctrl_link_mask;
22module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
23MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");
24
25static ulong ctrl_addr = 0x40000000;
26module_param_named(sdw_ctrl_addr, ctrl_addr, ulong, 0444);
27MODULE_PARM_DESC(sdw_ctrl_addr, "Intel SoundWire Controller _ADR");
28
29static bool is_link_enabled(struct fwnode_handle *fw_node, u8 idx)
30{
31 struct fwnode_handle *link;
32 char name[32];
33 u32 quirk_mask = 0;
34
35 /* Find master handle */
36 snprintf(buf: name, size: sizeof(name),
37 fmt: "mipi-sdw-link-%hhu-subproperties", idx);
38
39 link = fwnode_get_named_child_node(fwnode: fw_node, childname: name);
40 if (!link)
41 return false;
42
43 fwnode_property_read_u32(fwnode: link,
44 propname: "intel-quirk-mask",
45 val: &quirk_mask);
46
47 fwnode_handle_put(fwnode: link);
48
49 if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
50 return false;
51
52 return true;
53}
54
55static int
56sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
57{
58 struct acpi_device *adev = acpi_fetch_acpi_dev(handle: info->handle);
59 struct fwnode_handle *fwnode;
60 unsigned long list;
61 unsigned int i;
62 u32 count;
63 u32 tmp;
64 int ret;
65
66 if (!adev)
67 return -EINVAL;
68
69 fwnode = acpi_fwnode_handle(adev);
70
71 /*
72 * Found controller, find links supported
73 *
74 * In theory we could check the number of links supported in
75 * hardware, but in that step we cannot assume SoundWire IP is
76 * powered.
77 *
78 * In addition, if the BIOS doesn't even provide this
79 * 'master-count' property then all the inits based on link
80 * masks will fail as well.
81 *
82 * We will check the hardware capabilities in the startup() step
83 */
84 ret = fwnode_property_read_u32(fwnode, propname: "mipi-sdw-manager-list", val: &tmp);
85 if (ret) {
86 ret = fwnode_property_read_u32(fwnode, propname: "mipi-sdw-master-count", val: &count);
87 if (ret) {
88 dev_err(&adev->dev,
89 "Failed to read mipi-sdw-master-count: %d\n",
90 ret);
91 return ret;
92 }
93 list = GENMASK(count - 1, 0);
94 } else {
95 list = tmp;
96 count = hweight32(list);
97 }
98
99 /* Check count is within bounds */
100 if (count > SDW_INTEL_MAX_LINKS) {
101 dev_err(&adev->dev, "Link count %d exceeds max %d\n",
102 count, SDW_INTEL_MAX_LINKS);
103 return -EINVAL;
104 }
105
106 if (!count) {
107 dev_warn(&adev->dev, "No SoundWire links detected\n");
108 return -EINVAL;
109 }
110 dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
111
112 info->count = count;
113 info->link_mask = 0;
114
115 for_each_set_bit(i, &list, SDW_INTEL_MAX_LINKS) {
116 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
117 dev_dbg(&adev->dev,
118 "Link %d masked, will not be enabled\n", i);
119 continue;
120 }
121
122 if (!is_link_enabled(fw_node: fwnode, idx: i)) {
123 dev_dbg(&adev->dev,
124 "Link %d not selected in firmware\n", i);
125 continue;
126 }
127
128 info->link_mask |= BIT(i);
129 }
130
131 return 0;
132}
133
134static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
135 void *cdata, void **return_value)
136{
137 struct sdw_intel_acpi_info *info = cdata;
138 u64 adr;
139 int ret;
140
141 ret = acpi_get_local_u64_address(handle, addr: &adr);
142 if (ret < 0)
143 return AE_OK; /* keep going */
144
145 if (!acpi_fetch_acpi_dev(handle)) {
146 pr_err("%s: Couldn't find ACPI handle\n", __func__);
147 return AE_NOT_FOUND;
148 }
149
150 /*
151 * On some Intel platforms, multiple children of the HDAS
152 * device can be found, but only one of them is the SoundWire
153 * controller. The SNDW device is always exposed with
154 * Name(_ADR, 0x40000000), with bits 31..28 representing the
155 * SoundWire link so filter accordingly
156 */
157 if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
158 return AE_OK; /* keep going */
159
160 if (adr != ctrl_addr)
161 return AE_OK; /* keep going */
162
163 /* found the correct SoundWire controller */
164 info->handle = handle;
165
166 /* device found, stop namespace walk */
167 return AE_CTRL_TERMINATE;
168}
169
170/**
171 * sdw_intel_acpi_scan() - SoundWire Intel init routine
172 * @parent_handle: ACPI parent handle
173 * @info: description of what firmware/DSDT tables expose
174 *
175 * This scans the namespace and queries firmware to figure out which
176 * links to enable. A follow-up use of sdw_intel_probe() and
177 * sdw_intel_startup() is required for creation of devices and bus
178 * startup
179 */
180int sdw_intel_acpi_scan(acpi_handle parent_handle,
181 struct sdw_intel_acpi_info *info)
182{
183 acpi_status status;
184
185 info->handle = NULL;
186 /*
187 * In the HDAS ACPI scope, 'SNDW' may be either the child of
188 * 'HDAS' or the grandchild of 'HDAS'. So let's go through
189 * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW'
190 * device.
191 */
192 status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
193 start_object: parent_handle, max_depth: 2,
194 descending_callback: sdw_intel_acpi_cb,
195 NULL, context: info, NULL);
196 if (ACPI_FAILURE(status) || info->handle == NULL)
197 return -ENODEV;
198
199 return sdw_intel_scan_controller(info);
200}
201EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, "SND_INTEL_SOUNDWIRE_ACPI");
202
203MODULE_LICENSE("Dual BSD/GPL");
204MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");
205