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         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");