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 bool is_link_enabled(struct fwnode_handle *fw_node, int i)
  27 {
  28         struct fwnode_handle *link;
  29         char name[32];
  30         u32 quirk_mask = 0;
  31
  32         /* Find master handle */
  33         snprintf(name, sizeof(name),
  34                  "mipi-sdw-link-%d-subproperties", i);
  35
  36         link = fwnode_get_named_child_node(fw_node, name);
  37         if (!link)
  38                 return false;
  39
  40         fwnode_property_read_u32(link,
  41                                  "intel-quirk-mask",
  42                                  &quirk_mask);
  43
  44         if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
  45                 return false;
  46
  47         return true;
  48 }
  49
  50 static int
  51 sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
  52 {
  53         struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);
  54         int ret, i;
  55         u8 count;
  56
  57         if (!adev)
  58                 return -EINVAL;
  59
  60         /* Found controller, find links supported */
  61         count = 0;
  62         ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
  63                                             "mipi-sdw-master-count", &count, 1);
  64
  65         /*
  66          * In theory we could check the number of links supported in
  67          * hardware, but in that step we cannot assume SoundWire IP is
  68          * powered.
  69          *
  70          * In addition, if the BIOS doesn't even provide this
  71          * 'master-count' property then all the inits based on link
  72          * masks will fail as well.
  73          *
  74          * We will check the hardware capabilities in the startup() step
  75          */
  76
  77         if (ret) {
  78                 dev_err(&adev->dev,
  79                         "Failed to read mipi-sdw-master-count: %d\n", ret);
  80                 return -EINVAL;
  81         }
  82
  83         /* Check count is within bounds */
  84         if (count > SDW_MAX_LINKS) {
  85                 dev_err(&adev->dev, "Link count %d exceeds max %d\n",
  86                         count, SDW_MAX_LINKS);
  87                 return -EINVAL;
  88         }
  89
  90         if (!count) {
  91                 dev_warn(&adev->dev, "No SoundWire links detected\n");
  92                 return -EINVAL;
  93         }
  94         dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
  95
  96         info->count = count;
  97         info->link_mask = 0;
  98
  99         for (i = 0; i < count; i++) {
 100                 if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
 101                         dev_dbg(&adev->dev,
 102                                 "Link %d masked, will not be enabled\n", i);
 103                         continue;
 104                 }
 105
 106                 if (!is_link_enabled(acpi_fwnode_handle(adev), i)) {
 107                         dev_dbg(&adev->dev,
 108                                 "Link %d not selected in firmware\n", i);
 109                         continue;
 110                 }
 111
 112                 info->link_mask |= BIT(i);
 113         }
 114
 115         return 0;
 116 }
 117
 118 static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
 119                                      void *cdata, void **return_value)
 120 {
 121         struct sdw_intel_acpi_info *info = cdata;
 122         acpi_status status;
 123         u64 adr;
 124
 125         status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
 126         if (ACPI_FAILURE(status))
 127                 return AE_OK; /* keep going */
 128
 129         if (!acpi_fetch_acpi_dev(handle)) {
 130                 pr_err("%s: Couldn't find ACPI handle\n", __func__);
 131                 return AE_NOT_FOUND;
 132         }
 133
 134         /*
 135          * On some Intel platforms, multiple children of the HDAS
 136          * device can be found, but only one of them is the SoundWire
 137          * controller. The SNDW device is always exposed with
 138          * Name(_ADR, 0x40000000), with bits 31..28 representing the
 139          * SoundWire link so filter accordingly
 140          */
 141         if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
 142                 return AE_OK; /* keep going */
 143
 144         /* found the correct SoundWire controller */
 145         info->handle = handle;
 146
 147         /* device found, stop namespace walk */
 148         return AE_CTRL_TERMINATE;
 149 }
 150
 151 /**
 152  * sdw_intel_acpi_scan() - SoundWire Intel init routine
 153  * @parent_handle: ACPI parent handle
 154  * @info: description of what firmware/DSDT tables expose
 155  *
 156  * This scans the namespace and queries firmware to figure out which
 157  * links to enable. A follow-up use of sdw_intel_probe() and
 158  * sdw_intel_startup() is required for creation of devices and bus
 159  * startup
 160  */
 161 int sdw_intel_acpi_scan(acpi_handle *parent_handle,
 162                         struct sdw_intel_acpi_info *info)
 163 {
 164         acpi_status status;
 165
 166         info->handle = NULL;
 167         /*
 168          * In the HDAS ACPI scope, 'SNDW' may be either the child of
 169          * 'HDAS' or the grandchild of 'HDAS'. So let's go through
 170          * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW'
 171          * device.
 172          */
 173         status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
 174                                      parent_handle, 2,
 175                                      sdw_intel_acpi_cb,
 176                                      NULL, info, NULL);
 177         if (ACPI_FAILURE(status) || info->handle == NULL)
 178                 return -ENODEV;
 179
 180         return sdw_intel_scan_controller(info);
 181 }
 182 EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI);
 183
 184 MODULE_LICENSE("Dual BSD/GPL");
 185 MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");