greybus: audio: Add direct audio streaming control for APBridgeA

The latest audio architecture does not stream audio data over the
USB link between the AP and APBridgeA.  Instead, audio data is
streamed directly over the I2S link between the two.

To support the Greybus audio driver in setting up the I2S port and
controling packeting/depacketizing of audio data to/from Greybus
audio messages, define a set of commands and their parameters.
These commands and parameters will be placed into a request and sent
over the USB control channel to APBridgeA.  A corresponding driver
on APBridgeA will receive and process the requests.
Signed-off-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/staging/greybus/Makefile

@@ -31,6 +31,7 @@ gb-es2-y := es2.o
 gb-arche-y := arche-platform.o arche-apb-ctrl.o
 gb-audio-codec-y := audio_codec.o
 gb-audio-gb-y := audio_gb.o
+gb-audio-apbridgea-y := audio_apbridgea.o
 gb-camera-y := camera.o
 
 obj-m += greybus.o
@@ -46,6 +47,7 @@ obj-m += gb-arche.o
 obj-m += gb-audio-codec.o
 obj-m += gb-camera.o
 obj-m += gb-audio-gb.o
+obj-m += gb-audio-apbridgea.o
 
 KERNELVER		?= $(shell uname -r)
 KERNELDIR 		?= /lib/modules/$(KERNELVER)/build

drivers/staging/greybus/audio.h

@@ -121,6 +121,29 @@ extern int gb_audio_gb_activate_rx(struct gb_connection *connection,
 				   uint16_t data_cport);
 extern int gb_audio_gb_deactivate_rx(struct gb_connection *connection,
 				     uint16_t data_cport);
+extern int gb_audio_apbridgea_set_config(struct gb_connection *connection,
+					 __u16 i2s_port, __u32 format,
+					 __u32 rate, __u32 mclk_freq);
+extern int gb_audio_apbridgea_register_cport(struct gb_connection *connection,
+					     __u16 i2s_port, __u16 cportid);
+extern int gb_audio_apbridgea_unregister_cport(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 cportid);
+extern int gb_audio_apbridgea_set_tx_data_size(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 size);
+extern int gb_audio_apbridgea_get_tx_delay(struct gb_connection *connection,
+					   __u16 i2s_port, __u32 *delay);
+extern int gb_audio_apbridgea_start_tx(struct gb_connection *connection,
+				       __u16 i2s_port, __u64 timestamp);
+extern int gb_audio_apbridgea_stop_tx(struct gb_connection *connection,
+				      __u16 i2s_port);
+extern int gb_audio_apbridgea_set_rx_data_size(struct gb_connection *connection,
+					       __u16 i2s_port, __u16 size);
+extern int gb_audio_apbridgea_get_rx_delay(struct gb_connection *connection,
+					   __u16 i2s_port, __u32 *delay);
+extern int gb_audio_apbridgea_start_rx(struct gb_connection *connection,
+				       __u16 i2s_port);
+extern int gb_audio_apbridgea_stop_rx(struct gb_connection *connection,
+				      __u16 i2s_port);
 
 #endif /* __KERNEL__ */
 #endif /* __LINUX_GBAUDIO_H */

drivers/staging/greybus/audio_apbridgea.c

+/*
+ * Greybus Audio Device Class Protocol helpers
+ *
+ * Copyright 2015-2016 Google Inc.
+ *
+ * Released under the GPLv2 only.
+ */
+
+#include "greybus.h"
+#include "greybus_protocols.h"
+#include "audio_apbridgea.h"
+
+int gb_audio_apbridgea_set_config(struct gb_connection *connection,
+				  __u16 i2s_port, __u32 format, __u32 rate,
+				  __u32 mclk_freq)
+{
+	struct audio_apbridgea_set_config_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_CONFIG;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.format = cpu_to_le32(format);
+	req.rate = cpu_to_le32(rate);
+	req.mclk_freq = cpu_to_le32(mclk_freq);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_config);
+
+int gb_audio_apbridgea_register_cport(struct gb_connection *connection,
+				      __u16 i2s_port, __u16 cportid)
+{
+	struct audio_apbridgea_register_cport_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_REGISTER_CPORT;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.cport = cpu_to_le16(cportid);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_register_cport);
+
+int gb_audio_apbridgea_unregister_cport(struct gb_connection *connection,
+					__u16 i2s_port, __u16 cportid)
+{
+	struct audio_apbridgea_unregister_cport_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_UNREGISTER_CPORT;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.cport = cpu_to_le16(cportid);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_unregister_cport);
+
+int gb_audio_apbridgea_set_tx_data_size(struct gb_connection *connection,
+					__u16 i2s_port, __u16 size)
+{
+	struct audio_apbridgea_set_tx_data_size_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_TX_DATA_SIZE;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.size = cpu_to_le16(size);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_tx_data_size);
+
+int gb_audio_apbridgea_get_tx_delay(struct gb_connection *connection,
+				    __u16 i2s_port, __u32 *delay)
+{
+	/* TODO: implement */
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_get_tx_delay);
+
+int gb_audio_apbridgea_start_tx(struct gb_connection *connection,
+				__u16 i2s_port, __u64 timestamp)
+{
+	struct audio_apbridgea_start_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_START_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.timestamp = cpu_to_le64(timestamp);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_start_tx);
+
+int gb_audio_apbridgea_stop_tx(struct gb_connection *connection, __u16 i2s_port)
+{
+	struct audio_apbridgea_stop_tx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_STOP_TX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_stop_tx);
+
+int gb_audio_apbridgea_set_rx_data_size(struct gb_connection *connection,
+					__u16 i2s_port, __u16 size)
+{
+	struct audio_apbridgea_set_rx_data_size_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_SET_RX_DATA_SIZE;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+	req.size = cpu_to_le16(size);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_set_rx_data_size);
+
+int gb_audio_apbridgea_get_rx_delay(struct gb_connection *connection,
+				    __u16 i2s_port, __u32 *delay)
+{
+	/* TODO: implement */
+	return -ENOSYS;
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_get_rx_delay);
+
+int gb_audio_apbridgea_start_rx(struct gb_connection *connection,
+				__u16 i2s_port)
+{
+	struct audio_apbridgea_start_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_START_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_start_rx);
+
+int gb_audio_apbridgea_stop_rx(struct gb_connection *connection, __u16 i2s_port)
+{
+	struct audio_apbridgea_stop_rx_request req;
+
+	req.hdr.type = AUDIO_APBRIDGEA_TYPE_STOP_RX;
+	req.hdr.i2s_port = cpu_to_le16(i2s_port);
+
+	return gb_hd_output(connection->hd, &req, sizeof(req),
+			    GB_APB_REQUEST_AUDIO_CONTROL, true);
+}
+EXPORT_SYMBOL_GPL(gb_audio_apbridgea_stop_rx);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("greybus:audio-apbridgea");
+MODULE_DESCRIPTION("Greybus Special APBridgeA Audio Protocol library");
+MODULE_AUTHOR("Mark Greer <mgreer@animalcreek.com>");

drivers/staging/greybus/audio_apbridgea.h

+/**
+ * Copyright (c) 2015-2016 Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ * 3. Neither the name of the copyright holder nor the names of its
+ * contributors may be used to endorse or promote products derived from this
+ * software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+/*
+ * This is a special protocol for configuring communication over the
+ * I2S bus between the DSP on the MSM8994 and APBridgeA.  Therefore,
+ * we can predefine several low-level attributes of the communication
+ * because we know that they are supported.  In particular, the following
+ * assumptions are made:
+ *	- there are two channels (i.e., stereo)
+ *	- the low-level protocol is I2S as defined by Philips/NXP
+ *	- the DSP on the MSM8994 is the clock master for MCLK, BCLK, and WCLK
+ *	- WCLK changes on the falling edge of BCLK
+ *	- WCLK low for left channel; high for right channel
+ *	- TX data is sent on the falling edge of BCLK
+ *	- RX data is received/latched on the rising edge of BCLK
+ */
+
+#ifndef __AUDIO_APBRIDGEA_H
+#define __AUDIO_APBRIDGEA_H
+
+#define AUDIO_APBRIDGEA_TYPE_SET_CONFIG			0x01
+#define AUDIO_APBRIDGEA_TYPE_REGISTER_CPORT		0x02
+#define AUDIO_APBRIDGEA_TYPE_UNREGISTER_CPORT		0x03
+#define AUDIO_APBRIDGEA_TYPE_SET_TX_DATA_SIZE		0x04
+#define AUDIO_APBRIDGEA_TYPE_GET_TX_DELAY		0x05
+#define AUDIO_APBRIDGEA_TYPE_START_TX			0x06
+#define AUDIO_APBRIDGEA_TYPE_STOP_TX			0x07
+#define AUDIO_APBRIDGEA_TYPE_SET_RX_DATA_SIZE		0x08
+#define AUDIO_APBRIDGEA_TYPE_GET_RX_DELAY		0x09
+#define AUDIO_APBRIDGEA_TYPE_START_RX			0x0a
+#define AUDIO_APBRIDGEA_TYPE_STOP_RX			0x0b
+
+#define AUDIO_APBRIDGEA_PCM_FMT_8			BIT(0)
+#define AUDIO_APBRIDGEA_PCM_FMT_16			BIT(1)
+#define AUDIO_APBRIDGEA_PCM_FMT_24			BIT(2)
+#define AUDIO_APBRIDGEA_PCM_FMT_32			BIT(3)
+#define AUDIO_APBRIDGEA_PCM_FMT_64			BIT(4)
+
+#define AUDIO_APBRIDGEA_PCM_RATE_5512			BIT(0)
+#define AUDIO_APBRIDGEA_PCM_RATE_8000			BIT(1)
+#define AUDIO_APBRIDGEA_PCM_RATE_11025			BIT(2)
+#define AUDIO_APBRIDGEA_PCM_RATE_16000			BIT(3)
+#define AUDIO_APBRIDGEA_PCM_RATE_22050			BIT(4)
+#define AUDIO_APBRIDGEA_PCM_RATE_32000			BIT(5)
+#define AUDIO_APBRIDGEA_PCM_RATE_44100			BIT(6)
+#define AUDIO_APBRIDGEA_PCM_RATE_48000			BIT(7)
+#define AUDIO_APBRIDGEA_PCM_RATE_64000			BIT(8)
+#define AUDIO_APBRIDGEA_PCM_RATE_88200			BIT(9)
+#define AUDIO_APBRIDGEA_PCM_RATE_96000			BIT(10)
+#define AUDIO_APBRIDGEA_PCM_RATE_176400			BIT(11)
+#define AUDIO_APBRIDGEA_PCM_RATE_192000			BIT(12)
+
+/* The I2S port is passed in the 'index' parameter of the USB request */
+/* The CPort is passed in the 'value' parameter of the USB request */
+
+struct audio_apbridgea_hdr {
+	__u8	type;
+	__le16	i2s_port;
+	__u8	data[0];
+} __packed;
+
+struct audio_apbridgea_set_config_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le32				format;	/* AUDIO_APBRIDGEA_PCM_FMT_* */
+	__le32				rate;	/* AUDIO_APBRIDGEA_PCM_RATE_* */
+	__le32				mclk_freq; /* XXX Remove? */
+} __packed;
+
+struct audio_apbridgea_register_cport_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				cport;
+} __packed;
+
+struct audio_apbridgea_unregister_cport_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				cport;
+} __packed;
+
+struct audio_apbridgea_set_tx_data_size_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				size;
+} __packed;
+
+struct audio_apbridgea_get_tx_delay_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_get_tx_delay_response {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				delay;
+} __packed;
+
+struct audio_apbridgea_start_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le64				timestamp;
+} __packed;
+
+struct audio_apbridgea_stop_tx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_set_rx_data_size_request {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				size;
+} __packed;
+
+struct audio_apbridgea_get_rx_delay_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_get_rx_delay_response {
+	struct audio_apbridgea_hdr	hdr;
+	__le16				delay;
+} __packed;
+
+struct audio_apbridgea_start_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+struct audio_apbridgea_stop_rx_request {
+	struct audio_apbridgea_hdr	hdr;
+} __packed;
+
+#endif /*__AUDIO_APBRIDGEA_H */

drivers/staging/greybus/greybus_protocols.h

@@ -175,6 +175,9 @@ struct gb_control_interface_version_response {
 /* request to control the CSI transmitter */
 #define GB_APB_REQUEST_CSI_TX_CONTROL	0x08
 
+/* request to control the CSI transmitter */
+#define GB_APB_REQUEST_AUDIO_CONTROL	0x09
+
 
 /* Firmware Protocol */