ASoC: SOF: add SOF_DBG_CHECK_SDW_PERIPHERAL debug flag

If the flag is set, the driver waits for and verifies the presence of
SoundWire peripherals listed in the ACPI table. This prevents the system
from probing non-existent (ghost) SoundWire devices.

Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>

Author: bardliao

sound/soc/sof/intel/hda.c

@@ -1306,6 +1306,8 @@ static struct snd_soc_acpi_adr_device *find_acpi_adr_device(struct device *dev,
 	return adr_dev;
 }
 
+#define SDW_ENUM_TIMEOUT_MS 3000
+
 static struct snd_soc_acpi_mach *hda_sdw_machine_select(struct snd_sof_dev *sdev)
 {
 	struct snd_sof_pdata *pdata = sdev->pdata;
@@ -1315,7 +1317,9 @@ static struct snd_soc_acpi_mach *hda_sdw_machine_select(struct snd_sof_dev *sdev
 	struct sdw_peripherals *peripherals;
 	struct snd_soc_acpi_mach *mach;
 	struct sof_intel_hda_dev *hdev;
+	struct sdw_slave *slave;
 	int link_index, link_num;
+	unsigned long time;
 	int amp_index = 1;
 	u32 link_mask = 0;
 	int i;
@@ -1416,14 +1420,32 @@ static struct snd_soc_acpi_mach *hda_sdw_machine_select(struct snd_sof_dev *sdev
 	if (!links)
 		return NULL;
 
+	/*
+	 * Recalculate the link_mask as a link will be empty if all peripherals on the link are 
+	 * not enumerated
+	 */
+	link_mask = 0;
 	/* Generate snd_soc_acpi_link_adr struct for each peripheral reported by the ACPI table */
 	for (i = 0; i < peripherals->num_peripherals; i++) {
+		slave = peripherals->array[i];
+
+		/* Check if the SoundWire peripheral is present */
+		if (sof_debug_check_flag(SOF_DBG_CHECK_SDW_PERIPHERAL) && !slave->dev_num_sticky) {
+			/* Wait for the peripheral to enumerate */
+			time = wait_for_completion_timeout(&slave->enumeration_complete,
+							   msecs_to_jiffies(SDW_ENUM_TIMEOUT_MS));
+			if (!time) {
+				dev_warn(&slave->dev, "SoundWire peripheral is not present\n");
+				continue;
+			}
+		}
 		/* link_index = the number of used links below the current link */
-		link_index = hweight32(link_mask & (BIT(peripherals->array[i]->bus->link_id) - 1));
-		links[link_index].adr_d = find_acpi_adr_device(sdev->dev, peripherals->array[i],
+		link_index = hweight32(link_mask & (BIT(slave->bus->link_id) - 1));
+		links[link_index].adr_d = find_acpi_adr_device(sdev->dev, slave,
 							       &links[link_index], &amp_index);
 		if (!links[link_index].adr_d)
 			return NULL;
+		link_mask |= BIT(slave->bus->link_id);
 	}
 
 	mach->drv_name = "sof_sdw";

sound/soc/sof/sof-priv.h

@@ -56,6 +56,9 @@ struct snd_sof_pcm_stream;
 							 * DSPLESS_MODE is not set.
 							 * No audio functionality when enabled.
 							 */
+#define SOF_DBG_CHECK_SDW_PERIPHERAL		BIT(17) /* Check if SoundWire peripherals are
+							 * present while selecting machine driver
+							 */
 
 /* Flag definitions used for controlling the DSP dump behavior */
 #define SOF_DBG_DUMP_REGS		BIT(0)