1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2 // Copyright(c) 2015-2021 Intel Corporation.
5 * SDW Intel ACPI scan helpers
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/fwnode.h>
15 #include <linux/module.h>
16 #include <linux/soundwire/sdw_intel.h>
17 #include <linux/string.h>
19 #define SDW_LINK_TYPE 4 /* from Intel ACPI documentation */
20 #define SDW_MAX_LINKS 4
22 static int ctrl_link_mask;
23 module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
24 MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");
26 static ulong ctrl_addr = 0x40000000;
27 module_param_named(sdw_ctrl_addr, ctrl_addr, ulong, 0444);
28 MODULE_PARM_DESC(sdw_ctrl_addr, "Intel SoundWire Controller _ADR");
30 static bool is_link_enabled(struct fwnode_handle *fw_node, u8 idx)
32 struct fwnode_handle *link;
36 /* Find master handle */
37 snprintf(name, sizeof(name),
38 "mipi-sdw-link-%hhu-subproperties", idx);
40 link = fwnode_get_named_child_node(fw_node, name);
44 fwnode_property_read_u32(link,
48 if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
55 sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
57 struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);
64 /* Found controller, find links supported */
66 ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
67 "mipi-sdw-master-count", &count, 1);
70 * In theory we could check the number of links supported in
71 * hardware, but in that step we cannot assume SoundWire IP is
74 * In addition, if the BIOS doesn't even provide this
75 * 'master-count' property then all the inits based on link
76 * masks will fail as well.
78 * We will check the hardware capabilities in the startup() step
83 "Failed to read mipi-sdw-master-count: %d\n", ret);
87 /* Check count is within bounds */
88 if (count > SDW_MAX_LINKS) {
89 dev_err(&adev->dev, "Link count %d exceeds max %d\n",
90 count, SDW_MAX_LINKS);
95 dev_warn(&adev->dev, "No SoundWire links detected\n");
98 dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
103 for (i = 0; i < count; i++) {
104 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
106 "Link %d masked, will not be enabled\n", i);
110 if (!is_link_enabled(acpi_fwnode_handle(adev), i)) {
112 "Link %d not selected in firmware\n", i);
116 info->link_mask |= BIT(i);
122 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
123 void *cdata, void **return_value)
125 struct sdw_intel_acpi_info *info = cdata;
129 status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
130 if (ACPI_FAILURE(status))
131 return AE_OK; /* keep going */
133 if (!acpi_fetch_acpi_dev(handle)) {
134 pr_err("%s: Couldn't find ACPI handle\n", __func__);
139 * On some Intel platforms, multiple children of the HDAS
140 * device can be found, but only one of them is the SoundWire
141 * controller. The SNDW device is always exposed with
142 * Name(_ADR, 0x40000000), with bits 31..28 representing the
143 * SoundWire link so filter accordingly
145 if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
146 return AE_OK; /* keep going */
148 if (adr != ctrl_addr)
149 return AE_OK; /* keep going */
151 /* found the correct SoundWire controller */
152 info->handle = handle;
154 /* device found, stop namespace walk */
155 return AE_CTRL_TERMINATE;
159 * sdw_intel_acpi_scan() - SoundWire Intel init routine
160 * @parent_handle: ACPI parent handle
161 * @info: description of what firmware/DSDT tables expose
163 * This scans the namespace and queries firmware to figure out which
164 * links to enable. A follow-up use of sdw_intel_probe() and
165 * sdw_intel_startup() is required for creation of devices and bus
168 int sdw_intel_acpi_scan(acpi_handle *parent_handle,
169 struct sdw_intel_acpi_info *info)
175 * In the HDAS ACPI scope, 'SNDW' may be either the child of
176 * 'HDAS' or the grandchild of 'HDAS'. So let's go through
177 * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW'
180 status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
184 if (ACPI_FAILURE(status) || info->handle == NULL)
187 return sdw_intel_scan_controller(info);
189 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI);
191 MODULE_LICENSE("Dual BSD/GPL");
192 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");