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
  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");