sound/hda/intel-sdw-acpi.c

   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");