intel-sdw-acpi.c

  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(name, sizeof(name),
 37		 "mipi-sdw-link-%hhu-subproperties", idx);
 38
 39	link = fwnode_get_named_child_node(fw_node, name);
 40	if (!link)
 41		return false;
 42
 43	fwnode_property_read_u32(link,
 44				 "intel-quirk-mask",
 45				 &quirk_mask);
 46
 47	fwnode_handle_put(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(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, "mipi-sdw-manager-list", &tmp);
 85	if (ret) {
 86		ret = fwnode_property_read_u32(fwnode, "mipi-sdw-master-count", &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(fwnode, 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, &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				     parent_handle, 2,
194				     sdw_intel_acpi_cb,
195				     NULL, 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");