[PATCH v5 26/32] sound: Pass USB SND card and PCM information to SOC USB

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

Currently, only the index to the USB SND card array is passed to the USB
backend.  Pass through more information, specifically the USB SND card
number and the number of PCM devices available.  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@xxxxxxxxxxx>
---
 sound/soc/qcom/qdsp6/q6usb.c      | 19 ++++++++++++++++++-
 sound/usb/qcom/qc_audio_offload.c | 21 ++++++++++++++++++---
 2 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/sound/soc/qcom/qdsp6/q6usb.c b/sound/soc/qcom/qdsp6/q6usb.c
index e7b9c34fd5bd..1b2c72397570 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;
 };
 
@@ -106,10 +114,19 @@ static int q6usb_alsa_connection_cb(struct snd_soc_usb *usb,
 
 	data = dev_get_drvdata(usb->component->dev);
 
-	if (connected)
+	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;
 }
 
diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index 7076f2bd1089..7d98ede94c0d 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -175,6 +175,21 @@ enum usb_qmi_audio_format {
 	USB_QMI_PCM_FORMAT_U32_BE,
 };
 
+static int usb_qmi_get_pcm_num(struct snd_usb_audio *chip, int direction)
+{
+	struct snd_usb_substream *subs = NULL;
+	struct snd_usb_stream *as;
+	int count = 0;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		subs = &as->substream[direction];
+		if (subs->ep_num)
+			count++;
+	}
+
+	return count;
+}
+
 static enum usb_qmi_audio_device_speed_enum_v01
 get_speed_info(enum usb_device_speed udev_speed)
 {
@@ -1574,6 +1589,8 @@ static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip)
 
 	sdev->card_idx = chip->card->number;
 	sdev->chip_idx = chip->index;
+	sdev->num_playback = usb_qmi_get_pcm_num(chip, 0);
+	sdev->num_capture = usb_qmi_get_pcm_num(chip, 1);
 	uadev[chip->card->number].sdev = sdev;
 
 	uaudio_qdev->last_card_num = chip->card->number;
@@ -1674,10 +1691,8 @@ static void qc_usb_audio_offload_disconnect(struct snd_usb_audio *chip)
 	mutex_unlock(&chip->mutex);
 
 	atomic_dec(&uaudio_qdev->qdev_in_use);
-	if (!atomic_read(&uaudio_qdev->qdev_in_use)) {
-		snd_soc_usb_disconnect(usb_get_usb_backend(udev));
+	if (!atomic_read(&uaudio_qdev->qdev_in_use))
 		qc_usb_audio_cleanup_qmi_dev();
-	}
 	mutex_unlock(&qdev_mutex);
 
 	xhci_sideband_unregister(dev->sb);