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/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 #define SDW_MAX_LINKS 4 21 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)"); 25 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"); 29 30 static bool is_link_enabled(struct fwnode_handle *fw_node, u8 idx) 31 { 32 struct fwnode_handle *link; 33 char name[32]; 34 u32 quirk_mask = 0; 35 36 /* Find master handle */ 37 snprintf(name, sizeof(name), 38 "mipi-sdw-link-%hhu-subproperties", idx); 39 40 link = fwnode_get_named_child_node(fw_node, name); 41 if (!link) 42 return false; 43 44 fwnode_property_read_u32(link, 45 "intel-quirk-mask", 46 &quirk_mask); 47 48 if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE) 49 return false; 50 51 return true; 52 } 53 54 static int 55 sdw_intel_scan_controller(struct sdw_intel_acpi_info *info) 56 { 57 struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle); 58 u8 count, i; 59 int ret; 60 61 if (!adev) 62 return -EINVAL; 63 64 /* Found controller, find links supported */ 65 count = 0; 66 ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev), 67 "mipi-sdw-master-count", &count, 1); 68 69 /* 70 * In theory we could check the number of links supported in 71 * hardware, but in that step we cannot assume SoundWire IP is 72 * powered. 73 * 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. 77 * 78 * We will check the hardware capabilities in the startup() step 79 */ 80 81 if (ret) { 82 dev_err(&adev->dev, 83 "Failed to read mipi-sdw-master-count: %d\n", ret); 84 return -EINVAL; 85 } 86 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); 91 return -EINVAL; 92 } 93 94 if (!count) { 95 dev_warn(&adev->dev, "No SoundWire links detected\n"); 96 return -EINVAL; 97 } 98 dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count); 99 100 info->count = count; 101 info->link_mask = 0; 102 103 for (i = 0; i < count; i++) { 104 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) { 105 dev_dbg(&adev->dev, 106 "Link %d masked, will not be enabled\n", i); 107 continue; 108 } 109 110 if (!is_link_enabled(acpi_fwnode_handle(adev), i)) { 111 dev_dbg(&adev->dev, 112 "Link %d not selected in firmware\n", i); 113 continue; 114 } 115 116 info->link_mask |= BIT(i); 117 } 118 119 return 0; 120 } 121 122 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level, 123 void *cdata, void **return_value) 124 { 125 struct sdw_intel_acpi_info *info = cdata; 126 acpi_status status; 127 u64 adr; 128 129 status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr); 130 if (ACPI_FAILURE(status)) 131 return AE_OK; /* keep going */ 132 133 if (!acpi_fetch_acpi_dev(handle)) { 134 pr_err("%s: Couldn't find ACPI handle\n", __func__); 135 return AE_NOT_FOUND; 136 } 137 138 /* 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 144 */ 145 if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE) 146 return AE_OK; /* keep going */ 147 148 if (adr != ctrl_addr) 149 return AE_OK; /* keep going */ 150 151 /* found the correct SoundWire controller */ 152 info->handle = handle; 153 154 /* device found, stop namespace walk */ 155 return AE_CTRL_TERMINATE; 156 } 157 158 /** 159 * sdw_intel_acpi_scan() - SoundWire Intel init routine 160 * @parent_handle: ACPI parent handle 161 * @info: description of what firmware/DSDT tables expose 162 * 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 166 * startup 167 */ 168 int sdw_intel_acpi_scan(acpi_handle *parent_handle, 169 struct sdw_intel_acpi_info *info) 170 { 171 acpi_status status; 172 173 info->handle = NULL; 174 /* 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' 178 * device. 179 */ 180 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, 181 parent_handle, 2, 182 sdw_intel_acpi_cb, 183 NULL, info, NULL); 184 if (ACPI_FAILURE(status) || info->handle == NULL) 185 return -ENODEV; 186 187 return sdw_intel_scan_controller(info); 188 } 189 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI); 190 191 MODULE_LICENSE("Dual BSD/GPL"); 192 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers"); 193