[PATCH v7 27/33] ASoC: qcom: qdsp6: Add support to track available USB PCM devices

[Wesley Cheng <quic_wcheng@quicinc.com>]

The USB backend should know about which sound resources are being shared
between the ASoC and USB SND paths.  This can be utilized to properly
select and maintain the offloading devices.

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
---
 sound/soc/qcom/qdsp6/q6usb.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c
index 329a7d4a3c01..d697cbe7f184 100644
--- a/sound/soc/qcom/qdsp6/q6usb.c
+++ b/sound/soc/qcom/qdsp6/q6usb.c
@@ -25,10 +25,18 @@
 
 #define SID_MASK	0xF
 
+struct q6usb_status {
+	unsigned int num_pcm;
+	unsigned int chip_index;
+	unsigned int pcm_index;
+};
+
 struct q6usb_port_data {
 	struct q6afe_usb_cfg usb_cfg;
 	struct snd_soc_usb *usb;
 	struct q6usb_offload priv;
+	unsigned long available_card_slot;
+	struct q6usb_status status[SNDRV_CARDS];
 	int active_idx;
 };
 
@@ -110,6 +118,14 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb,
 	if (connected) {
 		/* We only track the latest USB headset plugged in */
 		data->active_idx = sdev->card_idx;
+
+		set_bit(sdev->card_idx, &data->available_card_slot);
+		data->status[sdev->card_idx].num_pcm = sdev->num_playback;
+		data->status[sdev->card_idx].chip_index = sdev->chip_idx;
+	} else {
+		clear_bit(sdev->card_idx, &data->available_card_slot);
+		data->status[sdev->card_idx].num_pcm = 0;
+		data->status[sdev->card_idx].chip_index = 0;
 	}
 
 	return 0;