stereo call recording support

Patch that allows for call recording in
stereo (left channel: TX; right channel:
RX). Tested on Nexus 5 (MSM8974). Likely
works on other recent MSM chipsets as
well.

Change-Id: I934c252283d1346f9c1f6cf786ce2f661f20a049

Signed-off-by: flar2 <asegaert@gmail.com>

sound/soc/msm/qdsp6v2/msm-pcm-voice-v2.c

@@ -582,6 +582,8 @@ static struct snd_kcontrol_new msm_voice_controls[] = {
 				msm_voice_tty_mode_put),
 	SOC_SINGLE_MULTI_EXT("Slowtalk Enable", SND_SOC_NOPM, 0, VSID_MAX, 0, 2,
 				NULL, msm_voice_slowtalk_put),
+	/* Dummy control to expose stereo recording support in kernel to user-space */
+	SOC_SINGLE_EXT("Stereo Recording", SND_SOC_NOPM, 1, VSID_MAX, 0, NULL, NULL),
 #ifdef CONFIG_SEC_SOLUTION
 	SOC_SINGLE_MULTI_EXT("Sec Set DHA data", SND_SOC_NOPM, 0, 65535, 0, 14,
 				msm_sec_dha_get, msm_sec_dha_put),

sound/soc/msm/qdsp6v2/q6voice.c

@@ -4023,8 +4023,13 @@ static int voice_cvs_start_record(struct voice_data *v, uint32_t rec_mode)
 		cvs_start_record.hdr.token = 0;
 		cvs_start_record.hdr.opcode = VSS_IRECORD_CMD_START;
 
+		/* In order to enable stereo recording,
+		 * i.e. TX on the left and RX on the right
+		 * the respective ports need to be explicitly specified:
+		 * INCALL_RECORD_TX => 0x8003
+		 * INCALL_RECORD_RX => 0x8004 */
 		cvs_start_record.rec_mode.port_id =
-					VSS_IRECORD_PORT_ID_DEFAULT;
+					VSS_IRECORD_PORT_ID_TX_RX;
 		if (rec_mode == VOC_REC_UPLINK) {
 			cvs_start_record.rec_mode.rx_tap_point =
 					VSS_IRECORD_TAP_POINT_NONE;
@@ -4048,6 +4053,9 @@ static int voice_cvs_start_record(struct voice_data *v, uint32_t rec_mode)
 			goto fail;
 		}
 
+		/* Request stereo recording */
+		cvs_start_record.rec_mode.mode = VSS_IRECORD_MODE_TX_RX_STEREO;
+
 		v->cvs_state = CMD_STATUS_FAIL;
 
 		ret = apr_send_pkt(apr_cvs, (uint32_t *) &cvs_start_record);

sound/soc/msm/qdsp6v2/q6voice.h

@@ -518,6 +518,9 @@ struct vss_imemory_cmd_unmap_t {
 #define VSS_IRECORD_PORT_ID_DEFAULT			0x0000FFFF
 /* Default AFE port ID. */
 
+/* Port explicitly identifying TX and RX streams */
+#define VSS_IRECORD_PORT_ID_TX_RX			0x00008003
+
 #define VSS_IRECORD_TAP_POINT_NONE			0x00010F78
 /* Indicates no tapping for specified path. */