ALSA: hda: move Intel SoundWire ACPI scan to dedicated module

The ACPI scan capabilities is called from the intel-dspconfig as well
as the SOF/HDaudio drivers. This creates dependencies and randconfig issues
when HDaudio and SOF/SoundWire are not all configured as modules.

To simplify Kconfig dependencies between HDAudio, SoundWire, SOF and
intel-dspconfig, move the ACPI scan helpers to a dedicated
module. This follows the same idea as NHLT helpers which are already
handled as a dedicated module.

The only functional change is that the kernel parameter to filter
links is now handled by a different module, but that was only provided
for developers needing work-arounds for early BIOS releases.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: Bard Liao <bard.liao@intel.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Vinod Koul <vkoul@kernel.org>
Link: https://lore.kernel.org/r/20210302003125.1178419-7-pierre-louis.bossart@linux.intel.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 174 insertions, 0 deletions

diff --git a/sound/hda/intel-sdw-acpi.c b/sound/hda/intel-sdw-acpi.c
new file mode 100644
index 000000000000..6359936a1503
--- /dev/null
+++ b/sound/hda/intel-sdw-acpi.c
@@ -0,0 +1,174 @@
+// 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/export.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, int i)
+{
+	struct fwnode_handle *link;
+	char name[32];
+	u32 quirk_mask = 0;
+
+	/* Find master handle */
+	snprintf(name, sizeof(name),
+		 "mipi-sdw-link-%d-subproperties", i);
+
+	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;
+	int ret, i;
+	u8 count;
+
+	if (acpi_bus_get_device(info->handle, &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;
+	struct acpi_device *adev;
+	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_bus_get_device(handle, &adev)) {
+		pr_err("%s: Couldn't find ACPI handle\n", __func__);
+		return AE_NOT_FOUND;
+	}
+
+	info->handle = handle;
+
+	/*
+	 * 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 */
+
+	/* 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;
+	status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
+				     parent_handle, 1,
+				     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");