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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 helpers6 */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/fwnode.h>15#include <linux/module.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 int56sdw_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 supported73 *74 * In theory we could check the number of links supported in75 * hardware, but in that step we cannot assume SoundWire IP is76 * powered.77 *78 * In addition, if the BIOS doesn't even provide this79 * 'master-count' property then all the inits based on link80 * masks will fail as well.81 *82 * We will check the hardware capabilities in the startup() step83 */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 HDAS152 * device can be found, but only one of them is the SoundWire153 * controller. The SNDW device is always exposed with154 * Name(_ADR, 0x40000000), with bits 31..28 representing the155 * SoundWire link so filter accordingly156 */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 routine172 * @parent_handle: ACPI parent handle173 * @info: description of what firmware/DSDT tables expose174 *175 * This scans the namespace and queries firmware to figure out which176 * links to enable. A follow-up use of sdw_intel_probe() and177 * sdw_intel_startup() is required for creation of devices and bus178 * startup179 */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 of188 * 'HDAS' or the grandchild of 'HDAS'. So let's go through189 * 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");205