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 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 } 133 134 static 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 */ 180 int 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 } 201 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI); 202 203 MODULE_LICENSE("Dual BSD/GPL"); 204 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers"); 205