targets: add target for auracast_usb app

Adds build target for auracast_usb application.
diff --git a/targets/auracast_usb/nrf5340-mcu.ld b/targets/auracast_usb/nrf5340-mcu.ld
new file mode 100644
index 0000000..2e2e4f1
--- /dev/null
+++ b/targets/auracast_usb/nrf5340-mcu.ld
@@ -0,0 +1,220 @@
+/* Linker script for Nordic Semiconductor nRF5 devices
+ *
+ * Version: Sourcery G++ 4.5-1
+ * Support: https://support.codesourcery.com/GNUToolchain/
+ *
+ * Copyright (c) 2007, 2008, 2009, 2010 CodeSourcery, Inc.
+ *
+ * The authors hereby grant permission to use, copy, modify, distribute,
+ * and license this software and its documentation for any purpose, provided
+ * that existing copyright notices are retained in all copies and that this
+ * notice is included verbatim in any distributions.  No written agreement,
+ * license, or royalty fee is required for any of the authorized uses.
+ * Modifications to this software may be copyrighted by their authors
+ * and need not follow the licensing terms described here, provided that
+ * the new terms are clearly indicated on the first page of each file where
+ * they apply.
+ */
+OUTPUT_FORMAT ("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
+
+/* Linker script to place sections and symbol values. Should be used together
+ * with other linker script that defines memory regions FLASH and RAM.
+ * It references following symbols, which must be defined in code:
+ *   Reset_Handler : Entry of reset handler
+ *
+ * It defines following symbols, which code can use without definition:
+ *   __exidx_start
+ *   __exidx_end
+ *   __etext
+ *   __data_start__
+ *   __preinit_array_start
+ *   __preinit_array_end
+ *   __init_array_start
+ *   __init_array_end
+ *   __fini_array_start
+ *   __fini_array_end
+ *   __data_end__
+ *   __bss_start__
+ *   __bss_end__
+ *   __HeapBase
+ *   __HeapLimit
+ *   __StackLimit
+ *   __StackTop
+ *   __stack
+ *   __bssnz_start__
+ *   __bssnz_end__
+ */
+ENTRY(Reset_Handler)
+
+SECTIONS
+{
+    .imghdr (NOLOAD):
+    {
+        . = . + _imghdr_size;
+    } > FLASH
+
+    __text = .;
+
+    .text :
+    {
+        __isr_vector_start = .;
+        KEEP(*(.isr_vector))
+        __isr_vector_end = .;
+        EXCLUDE_FILE(*liblc3.a: *libm.a: *libsamplerate.a: *audio_usb.o) *(.text*)
+
+        KEEP(*(.init))
+        KEEP(*(.fini))
+
+        . = ALIGN(4);
+        /* preinit data */
+        PROVIDE_HIDDEN (__preinit_array_start = .);
+        KEEP(*(.preinit_array))
+        PROVIDE_HIDDEN (__preinit_array_end = .);
+
+        . = ALIGN(4);
+        /* init data */
+        PROVIDE_HIDDEN (__init_array_start = .);
+        KEEP(*(SORT(.init_array.*)))
+        KEEP(*(.init_array))
+        PROVIDE_HIDDEN (__init_array_end = .);
+
+        . = ALIGN(4);
+        /* finit data */
+        PROVIDE_HIDDEN (__fini_array_start = .);
+        KEEP(*(SORT(.fini_array.*)))
+        KEEP(*(.fini_array))
+        PROVIDE_HIDDEN (__fini_array_end = .);
+
+        /* .ctors */
+        *crtbegin.o(.ctors)
+        *crtbegin?.o(.ctors)
+        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .ctors)
+        *(SORT(.ctors.*))
+        *(.ctors)
+
+        /* .dtors */
+        *crtbegin.o(.dtors)
+        *crtbegin?.o(.dtors)
+        *(EXCLUDE_FILE(*crtend?.o *crtend.o) .dtors)
+        *(SORT(.dtors.*))
+        *(.dtors)
+
+        EXCLUDE_FILE(*liblc3.a: *libsamplerate.a:) *(.rodata*)
+
+        *(.eh_frame*)
+        PROVIDE(mynewt_main = main);
+        . = ALIGN(4);
+    } > FLASH
+
+
+    .net_core_img :
+    {
+        PROVIDE(net_core_img_start = .);
+        KEEP(*(.net_core_img));
+        PROVIDE(net_core_img_end = .);
+    } > FLASH
+
+    .ARM.extab :
+    {
+        *(.ARM.extab* .gnu.linkonce.armextab.*)
+        . = ALIGN(4);
+    } > FLASH
+
+    __exidx_start = .;
+    .ARM.exidx :
+    {
+        *(.ARM.exidx* .gnu.linkonce.armexidx.*)
+        . = ALIGN(4);
+    } > FLASH
+    __exidx_end = .;
+
+    __etext = .;
+
+    .vector_relocation :
+    {
+        . = ALIGN(4);
+        __vector_tbl_reloc__ = .;
+        . = . + (__isr_vector_end - __isr_vector_start);
+        . = ALIGN(4);
+    } > RAM
+
+    /* Section for app-net cores IPC */
+    .ipc 0x20000400 (NOLOAD):
+    {
+        . = ALIGN(4);
+        *(.ipc)
+        . = ALIGN(4);
+    } > RAM
+
+    /* This section will be zeroed by RTT package init */
+    .rtt (NOLOAD):
+    {
+        . = ALIGN(4);
+        *(.rtt)
+        . = ALIGN(4);
+    } > RAM
+
+    .data :
+    {
+        __data_start__ = .;
+        *(vtable)
+        *(.data*)
+
+        *(.jcr)
+        *liblc3.a:(.text* .rodata*)
+        *libsamplerate.a:(.text* .rodata*)
+        *audio_usb.o(.text*)
+        *libm.a:(.text*)
+        . = ALIGN(4);
+        /* All data end */
+        __data_end__ = .;
+    } > RAM AT > FLASH
+
+    /* Non-zeroed BSS.  This section is similar to BSS, but does not get zeroed at init-time.
+     */
+    .bssnz :
+    {
+        . = ALIGN(4);
+        __bssnz_start__ = .;
+        *(.bss.core.nz*)
+        . = ALIGN(4);
+        __bssnz_end__ = .;
+    } > RAM
+
+    .bss :
+    {
+        . = ALIGN(4);
+        __bss_start__ = .;
+        *(.bss*)
+        *(COMMON)
+        . = ALIGN(4);
+        __bss_end__ = .;
+    } > RAM
+
+    /* Heap starts after BSS */
+    . = ALIGN(8);
+    __HeapBase = .;
+
+    /* .stack_dummy section doesn't contains any symbols. It is only
+     * used for linker to calculate size of stack sections, and assign
+     * values to stack symbols later */
+    .stack_dummy (COPY):
+    {
+        *(.stack*)
+    } > RAM
+
+    _ram_start = ORIGIN(RAM);
+
+    /* Set stack top to end of RAM, and stack limit move down by
+     * size of stack_dummy section */
+    __StackTop = ORIGIN(RAM) + LENGTH(RAM);
+    __StackLimit = __StackTop - SIZEOF(.stack_dummy);
+    PROVIDE(__stack = __StackTop);
+
+    /* Top of head is the bottom of the stack */
+    __HeapLimit = __StackLimit;
+
+    /* Check if data + heap + stack exceeds RAM limit */
+    ASSERT(__HeapBase <= __HeapLimit, "region RAM overflowed with stack")
+}
+
diff --git a/targets/auracast_usb/nrf5340.ld b/targets/auracast_usb/nrf5340.ld
new file mode 100644
index 0000000..6ee5122
--- /dev/null
+++ b/targets/auracast_usb/nrf5340.ld
@@ -0,0 +1,26 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+MEMORY
+{
+  FLASH (rx) : ORIGIN = 0x0000c000, LENGTH = 0x76000
+  RAM (rwx) : ORIGIN = 0x20000000, LENGTH = 0x80000
+}
+
+/* This linker script is used for images and thus contains an image header */
+_imghdr_size = 0x20;
diff --git a/targets/auracast_usb/pkg.yml b/targets/auracast_usb/pkg.yml
new file mode 100755
index 0000000..379a8ac
--- /dev/null
+++ b/targets/auracast_usb/pkg.yml
@@ -0,0 +1,24 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+pkg.name: targets/auracast_usb
+pkg.type: target
+pkg.description: 
+pkg.author: 
+pkg.homepage:
diff --git a/targets/auracast_usb/syscfg.yml b/targets/auracast_usb/syscfg.yml
new file mode 100755
index 0000000..2e58b5c
--- /dev/null
+++ b/targets/auracast_usb/syscfg.yml
@@ -0,0 +1,25 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+syscfg.vals.BSP_NRF5340:
+    MCU_MPU_ENABLE: 0
+    MCU_CACHE_ENABLED: 1
+    BSP_NRF5340_NET_ENABLE: 1
+    NRF5340_EMBED_NET_CORE: 1
+    NET_CORE_IMAGE_TARGET_NAME: "@apache-mynewt-nimble/targets/nordic_pca10095_net-blehci_broadcaster"
diff --git a/targets/auracast_usb/target.yml b/targets/auracast_usb/target.yml
new file mode 100755
index 0000000..3aa75b5
--- /dev/null
+++ b/targets/auracast_usb/target.yml
@@ -0,0 +1,27 @@
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#  http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+#
+
+target.app: "@apache-mynewt-nimble/apps/auracast_usb"
+target.bsp: "@apache-mynewt-core/hw/bsp/nordic_pca10121"
+target.build_profile: speed
+
+# linkerscrupt that moves audio processing to RAM, for better performance
+bsp.linkerscript:
+    - "@apache-mynewt-nimble/targets/auracast_usb/nrf5340.ld"
+    - "@apache-mynewt-nimble/targets/auracast_usb/nrf5340-mcu.ld"