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 21 static int ctrl_link_mask; 22 module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444); 23 MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)"); 24 25 static ulong ctrl_addr = 0x40000000; 26 module_param_named(sdw_ctrl_addr, ctrl_addr, ulong, 0444); 27 MODULE_PARM_DESC(sdw_ctrl_addr, "Intel SoundWire Controller _ADR"); 28 29 static 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 55 static int 56 sdw_intel_scan_controller(struct sdw_intel_acpi_info *info) 57 { 58 struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle); 59 u8 count, i; 60 int ret; 61 62 if (!adev) 63 return -EINVAL; 64 65 /* Found controller, find links supported */ 66 count = 0; 67 ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev), 68 "mipi-sdw-master-count", &count, 1); 69 70 /* 71 * In theory we could check the number of links supported in 72 * hardware, but in that step we cannot assume SoundWire IP is 73 * powered. 74 * 75 * In addition, if the BIOS doesn't even provide this 76 * 'master-count' property then all the inits based on link 77 * masks will fail as well. 78 * 79 * We will check the hardware capabilities in the startup() step 80 */ 81 82 if (ret) { 83 dev_err(&adev->dev, 84 "Failed to read mipi-sdw-master-count: %d\n", ret); 85 return -EINVAL; 86 } 87 88 /* Check count is within bounds */ 89 if (count > SDW_INTEL_MAX_LINKS) { 90 dev_err(&adev->dev, "Link count %d exceeds max %d\n", 91 count, SDW_INTEL_MAX_LINKS); 92 return -EINVAL; 93 } 94 95 if (!count) { 96 dev_warn(&adev->dev, "No SoundWire links detected\n"); 97 return -EINVAL; 98 } 99 dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count); 100 101 info->count = count; 102 info->link_mask = 0; 103 104 for (i = 0; i < count; i++) { 105 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) { 106 dev_dbg(&adev->dev, 107 "Link %d masked, will not be enabled\n", i); 108 continue; 109 } 110 111 if (!is_link_enabled(acpi_fwnode_handle(adev), i)) { 112 dev_dbg(&adev->dev, 113 "Link %d not selected in firmware\n", i); 114 continue; 115 } 116 117 info->link_mask |= BIT(i); 118 } 119 120 return 0; 121 } 122 123 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level, 124 void *cdata, void **return_value) 125 { 126 struct sdw_intel_acpi_info *info = cdata; 127 u64 adr; 128 int ret; 129 130 ret = acpi_get_local_u64_address(handle, &adr); 131 if (ret < 0) 132 return AE_OK; /* keep going */ 133 134 if (!acpi_fetch_acpi_dev(handle)) { 135 pr_err("%s: Couldn't find ACPI handle\n", __func__); 136 return AE_NOT_FOUND; 137 } 138 139 /* 140 * On some Intel platforms, multiple children of the HDAS 141 * device can be found, but only one of them is the SoundWire 142 * controller. The SNDW device is always exposed with 143 * Name(_ADR, 0x40000000), with bits 31..28 representing the 144 * SoundWire link so filter accordingly 145 */ 146 if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE) 147 return AE_OK; /* keep going */ 148 149 if (adr != ctrl_addr) 150 return AE_OK; /* keep going */ 151 152 /* found the correct SoundWire controller */ 153 info->handle = handle; 154 155 /* device found, stop namespace walk */ 156 return AE_CTRL_TERMINATE; 157 } 158 159 /** 160 * sdw_intel_acpi_scan() - SoundWire Intel init routine 161 * @parent_handle: ACPI parent handle 162 * @info: description of what firmware/DSDT tables expose 163 * 164 * This scans the namespace and queries firmware to figure out which 165 * links to enable. A follow-up use of sdw_intel_probe() and 166 * sdw_intel_startup() is required for creation of devices and bus 167 * startup 168 */ 169 int sdw_intel_acpi_scan(acpi_handle *parent_handle, 170 struct sdw_intel_acpi_info *info) 171 { 172 acpi_status status; 173 174 info->handle = NULL; 175 /* 176 * In the HDAS ACPI scope, 'SNDW' may be either the child of 177 * 'HDAS' or the grandchild of 'HDAS'. So let's go through 178 * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW' 179 * device. 180 */ 181 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, 182 parent_handle, 2, 183 sdw_intel_acpi_cb, 184 NULL, info, NULL); 185 if (ACPI_FAILURE(status) || info->handle == NULL) 186 return -ENODEV; 187 188 return sdw_intel_scan_controller(info); 189 } 190 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI); 191 192 MODULE_LICENSE("Dual BSD/GPL"); 193 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers"); 194