[PATCH v16 47/50] ALSA: usb-audio: qcom: Use card and PCM index from QMI request

[Wesley Cheng <quic_wcheng@xxxxxxxxxxx>]

Utilize the card and PCM index coming from the USB QMI stream request.
This field follows what is set by the ASoC USB backend, and could
potentially carry information about a specific device selected through the
ASoC USB backend.  The backend also has information about the last USB
sound device plugged in, so it can choose to select the last device plugged
in, accordingly.

Change-Id: I3083ab525f0cf1224814201036fd2ff8f9d44a34
Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
---
 sound/usb/card.c                  | 21 +++++++++++++++++++++
 sound/usb/card.h                  |  1 +
 sound/usb/qcom/qc_audio_offload.c | 10 ++++------
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/sound/usb/card.c b/sound/usb/card.c
index 1ad99a462038..8364c5b8fbbf 100644
--- a/sound/usb/card.c
+++ b/sound/usb/card.c
@@ -186,6 +186,27 @@ struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
 }
 EXPORT_SYMBOL_GPL(snd_usb_find_suppported_substream);
 
+/*
+ * in case the platform driver was not ready at the time of USB SND
+ * device connect, expose an API to discover all connected USB devices
+ * so it can populate any dependent resources/structures.
+ */
+void snd_usb_rediscover_devices(void)
+{
+	int i;
+
+	guard(mutex)(&register_mutex);
+
+	if (!platform_ops || !platform_ops->connect_cb)
+		return;
+
+	for (i = 0; i < SNDRV_CARDS; i++) {
+		if (usb_chip[i])
+			platform_ops->connect_cb(usb_chip[i]);
+	}
+}
+EXPORT_SYMBOL_GPL(snd_usb_rediscover_devices);
+
 /*
  * disconnect streams
  * called from usb_audio_disconnect()
diff --git a/sound/usb/card.h b/sound/usb/card.h
index 2c8c51c8b1ea..68c8c5f12c1a 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -221,4 +221,5 @@ int snd_usb_unregister_platform_ops(void);
 
 struct snd_usb_stream *snd_usb_find_suppported_substream(int card_idx,
 			struct snd_pcm_hw_params *params, int direction);
+void snd_usb_rediscover_devices(void);
 #endif /* __USBAUDIO_CARD_H */
diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index 6a25a390f8ae..5e7da9a033e5 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -107,8 +107,6 @@ struct uaudio_qmi_dev {
 	bool er_mapped;
 	/* reference count to number of possible consumers */
 	atomic_t qdev_in_use;
-	/* idx to last udev card number plugged in */
-	unsigned int last_card_num;
 };
 
 struct uaudio_dev {
@@ -1256,7 +1254,7 @@ static int prepare_qmi_response(struct snd_usb_substream *subs,
 
 	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
 	xfer_buf_len = req_msg->xfer_buff_size;
-	card_num = uaudio_qdev->last_card_num;
+	card_num = (req_msg->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;
 
 	if (!uadev[card_num].ctrl_intf) {
 		dev_err(&subs->dev->dev, "audio ctrl intf info not cached\n");
@@ -1449,8 +1447,7 @@ static void handle_uaudio_stream_req(struct qmi_handle *handle,
 
 	direction = (req_msg->usb_token & QMI_STREAM_REQ_DIRECTION);
 	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
-	pcm_card_num = req_msg->enable ? uaudio_qdev->last_card_num :
-				ffs(uaudio_qdev->card_slot) - 1;
+	pcm_card_num = (req_msg->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;
 	if (pcm_card_num >= SNDRV_CARDS) {
 		ret = -EINVAL;
 		goto response;
@@ -1658,7 +1655,6 @@ static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip)
 	sdev->num_capture = usb_qmi_get_pcm_num(chip, 1);
 	uadev[chip->card->number].sdev = sdev;
 
-	uaudio_qdev->last_card_num = chip->card->number;
 	snd_soc_usb_connect(usb_get_usb_backend(udev), sdev);
 
 	snd_usb_offload_create_ctl(chip);
@@ -1879,6 +1875,8 @@ static int __init qc_usb_audio_offload_init(void)
 	if (ret < 0)
 		goto release_qmi;
 
+	snd_usb_rediscover_devices();
+
 	return 0;
 
 release_qmi: