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 fwnode_handle_put(link); 49 50 if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE) 51 return false; 52 53 return true; 54 } 55 56 static int 57 sdw_intel_scan_controller(struct sdw_intel_acpi_info *info) 58 { 59 struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle); 60 u8 count, i; 61 int ret; 62 63 if (!adev) 64 return -EINVAL; 65 66 /* Found controller, find links supported */ 67 count = 0; 68 ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev), 69 "mipi-sdw-master-count", &count, 1); 70 71 /* 72 * In theory we could check the number of links supported in 73 * hardware, but in that step we cannot assume SoundWire IP is 74 * powered. 75 * 76 * In addition, if the BIOS doesn't even provide this 77 * 'master-count' property then all the inits based on link 78 * masks will fail as well. 79 * 80 * We will check the hardware capabilities in the startup() step 81 */ 82 83 if (ret) { 84 dev_err(&adev->dev, 85 "Failed to read mipi-sdw-master-count: %d\n", ret); 86 return -EINVAL; 87 } 88 89 /* Check count is within bounds */ 90 if (count > SDW_MAX_LINKS) { 91 dev_err(&adev->dev, "Link count %d exceeds max %d\n", 92 count, SDW_MAX_LINKS); 93 return -EINVAL; 94 } 95 96 if (!count) { 97 dev_warn(&adev->dev, "No SoundWire links detected\n"); 98 return -EINVAL; 99 } 100 dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count); 101 102 info->count = count; 103 info->link_mask = 0; 104 105 for (i = 0; i < count; i++) { 106 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) { 107 dev_dbg(&adev->dev, 108 "Link %d masked, will not be enabled\n", i); 109 continue; 110 } 111 112 if (!is_link_enabled(acpi_fwnode_handle(adev), i)) { 113 dev_dbg(&adev->dev, 114 "Link %d not selected in firmware\n", i); 115 continue; 116 } 117 118 info->link_mask |= BIT(i); 119 } 120 121 return 0; 122 } 123 124 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level, 125 void *cdata, void **return_value) 126 { 127 struct sdw_intel_acpi_info *info = cdata; 128 acpi_status status; 129 u64 adr; 130 131 status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr); 132 if (ACPI_FAILURE(status)) 133 return AE_OK; /* keep going */ 134 135 if (!acpi_fetch_acpi_dev(handle)) { 136 pr_err("%s: Couldn't find ACPI handle\n", __func__); 137 return AE_NOT_FOUND; 138 } 139 140 /* 141 * On some Intel platforms, multiple children of the HDAS 142 * device can be found, but only one of them is the SoundWire 143 * controller. The SNDW device is always exposed with 144 * Name(_ADR, 0x40000000), with bits 31..28 representing the 145 * SoundWire link so filter accordingly 146 */ 147 if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE) 148 return AE_OK; /* keep going */ 149 150 if (adr != ctrl_addr) 151 return AE_OK; /* keep going */ 152 153 /* found the correct SoundWire controller */ 154 info->handle = handle; 155 156 /* device found, stop namespace walk */ 157 return AE_CTRL_TERMINATE; 158 } 159 160 /** 161 * sdw_intel_acpi_scan() - SoundWire Intel init routine 162 * @parent_handle: ACPI parent handle 163 * @info: description of what firmware/DSDT tables expose 164 * 165 * This scans the namespace and queries firmware to figure out which 166 * links to enable. A follow-up use of sdw_intel_probe() and 167 * sdw_intel_startup() is required for creation of devices and bus 168 * startup 169 */ 170 int sdw_intel_acpi_scan(acpi_handle *parent_handle, 171 struct sdw_intel_acpi_info *info) 172 { 173 acpi_status status; 174 175 info->handle = NULL; 176 /* 177 * In the HDAS ACPI scope, 'SNDW' may be either the child of 178 * 'HDAS' or the grandchild of 'HDAS'. So let's go through 179 * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW' 180 * device. 181 */ 182 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, 183 parent_handle, 2, 184 sdw_intel_acpi_cb, 185 NULL, info, NULL); 186 if (ACPI_FAILURE(status) || info->handle == NULL) 187 return -ENODEV; 188 189 return sdw_intel_scan_controller(info); 190 } 191 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI); 192 193 MODULE_LICENSE("Dual BSD/GPL"); 194 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers"); 195