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-rw-r--r--sound/hda/intel-sdw-acpi.c185
1 files changed, 185 insertions, 0 deletions
diff --git a/sound/hda/intel-sdw-acpi.c b/sound/hda/intel-sdw-acpi.c
new file mode 100644
index 000000000..b57d72ea4
--- /dev/null
+++ b/sound/hda/intel-sdw-acpi.c
@@ -0,0 +1,185 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+// Copyright(c) 2015-2021 Intel Corporation.
+
+/*
+ * SDW Intel ACPI scan helpers
+ */
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fwnode.h>
+#include <linux/module.h>
+#include <linux/soundwire/sdw_intel.h>
+#include <linux/string.h>
+
+#define SDW_LINK_TYPE 4 /* from Intel ACPI documentation */
+#define SDW_MAX_LINKS 4
+
+static int ctrl_link_mask;
+module_param_named(sdw_link_mask, ctrl_link_mask, int, 0444);
+MODULE_PARM_DESC(sdw_link_mask, "Intel link mask (one bit per link)");
+
+static bool is_link_enabled(struct fwnode_handle *fw_node, u8 idx)
+{
+ struct fwnode_handle *link;
+ char name[32];
+ u32 quirk_mask = 0;
+
+ /* Find master handle */
+ snprintf(name, sizeof(name),
+ "mipi-sdw-link-%hhu-subproperties", idx);
+
+ link = fwnode_get_named_child_node(fw_node, name);
+ if (!link)
+ return false;
+
+ fwnode_property_read_u32(link,
+ "intel-quirk-mask",
+ &quirk_mask);
+
+ if (quirk_mask & SDW_INTEL_QUIRK_MASK_BUS_DISABLE)
+ return false;
+
+ return true;
+}
+
+static int
+sdw_intel_scan_controller(struct sdw_intel_acpi_info *info)
+{
+ struct acpi_device *adev = acpi_fetch_acpi_dev(info->handle);
+ u8 count, i;
+ int ret;
+
+ if (!adev)
+ return -EINVAL;
+
+ /* Found controller, find links supported */
+ count = 0;
+ ret = fwnode_property_read_u8_array(acpi_fwnode_handle(adev),
+ "mipi-sdw-master-count", &count, 1);
+
+ /*
+ * In theory we could check the number of links supported in
+ * hardware, but in that step we cannot assume SoundWire IP is
+ * powered.
+ *
+ * In addition, if the BIOS doesn't even provide this
+ * 'master-count' property then all the inits based on link
+ * masks will fail as well.
+ *
+ * We will check the hardware capabilities in the startup() step
+ */
+
+ if (ret) {
+ dev_err(&adev->dev,
+ "Failed to read mipi-sdw-master-count: %d\n", ret);
+ return -EINVAL;
+ }
+
+ /* Check count is within bounds */
+ if (count > SDW_MAX_LINKS) {
+ dev_err(&adev->dev, "Link count %d exceeds max %d\n",
+ count, SDW_MAX_LINKS);
+ return -EINVAL;
+ }
+
+ if (!count) {
+ dev_warn(&adev->dev, "No SoundWire links detected\n");
+ return -EINVAL;
+ }
+ dev_dbg(&adev->dev, "ACPI reports %d SDW Link devices\n", count);
+
+ info->count = count;
+ info->link_mask = 0;
+
+ for (i = 0; i < count; i++) {
+ if (ctrl_link_mask && !(ctrl_link_mask & BIT(i))) {
+ dev_dbg(&adev->dev,
+ "Link %d masked, will not be enabled\n", i);
+ continue;
+ }
+
+ if (!is_link_enabled(acpi_fwnode_handle(adev), i)) {
+ dev_dbg(&adev->dev,
+ "Link %d not selected in firmware\n", i);
+ continue;
+ }
+
+ info->link_mask |= BIT(i);
+ }
+
+ return 0;
+}
+
+static acpi_status sdw_intel_acpi_cb(acpi_handle handle, u32 level,
+ void *cdata, void **return_value)
+{
+ struct sdw_intel_acpi_info *info = cdata;
+ acpi_status status;
+ u64 adr;
+
+ status = acpi_evaluate_integer(handle, METHOD_NAME__ADR, NULL, &adr);
+ if (ACPI_FAILURE(status))
+ return AE_OK; /* keep going */
+
+ if (!acpi_fetch_acpi_dev(handle)) {
+ pr_err("%s: Couldn't find ACPI handle\n", __func__);
+ return AE_NOT_FOUND;
+ }
+
+ /*
+ * On some Intel platforms, multiple children of the HDAS
+ * device can be found, but only one of them is the SoundWire
+ * controller. The SNDW device is always exposed with
+ * Name(_ADR, 0x40000000), with bits 31..28 representing the
+ * SoundWire link so filter accordingly
+ */
+ if (FIELD_GET(GENMASK(31, 28), adr) != SDW_LINK_TYPE)
+ return AE_OK; /* keep going */
+
+ /* found the correct SoundWire controller */
+ info->handle = handle;
+
+ /* device found, stop namespace walk */
+ return AE_CTRL_TERMINATE;
+}
+
+/**
+ * sdw_intel_acpi_scan() - SoundWire Intel init routine
+ * @parent_handle: ACPI parent handle
+ * @info: description of what firmware/DSDT tables expose
+ *
+ * This scans the namespace and queries firmware to figure out which
+ * links to enable. A follow-up use of sdw_intel_probe() and
+ * sdw_intel_startup() is required for creation of devices and bus
+ * startup
+ */
+int sdw_intel_acpi_scan(acpi_handle *parent_handle,
+ struct sdw_intel_acpi_info *info)
+{
+ acpi_status status;
+
+ info->handle = NULL;
+ /*
+ * In the HDAS ACPI scope, 'SNDW' may be either the child of
+ * 'HDAS' or the grandchild of 'HDAS'. So let's go through
+ * the ACPI from 'HDAS' at max depth of 2 to find the 'SNDW'
+ * device.
+ */
+ status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
+ parent_handle, 2,
+ sdw_intel_acpi_cb,
+ NULL, info, NULL);
+ if (ACPI_FAILURE(status) || info->handle == NULL)
+ return -ENODEV;
+
+ return sdw_intel_scan_controller(info);
+}
+EXPORT_SYMBOL_NS(sdw_intel_acpi_scan, SND_INTEL_SOUNDWIRE_ACPI);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("Intel Soundwire ACPI helpers");