Switch to PortAudio

Switch to PortAudio for cross-platform and cross backend compatibility.

Linux v6.7 propose a solution to resolve sound stutter effect.
Therefore, upgrade the kernel version as well.

Author: Cuda-Chen

.clang-format

@@ -24,3 +24,5 @@ ForEachMacros:
   - hlist_for_each_entry
   - rb_list_foreach
   - rb_list_foreach_safe
+StatementAttributeLikeMacros:
+  - IIF

.gitmodules

@@ -1,12 +1,12 @@
-[submodule "cnfa"]
-    path = cnfa
-    url = https://github.com/cntools/cnfa
-    shallow = true
 [submodule "mini-gdbstub"]
     path = mini-gdbstub
     url = https://github.com/RinHizakura/mini-gdbstub
     shallow = true
 [submodule "minislirp"]
 	path = minislirp
 	url = https://github.com/edubart/minislirp
-    shallow = true
+    shallow = true
+[submodule "portaudio"]
+    path = portaudio
+    url = https://github.com/PortAudio/portaudio
+    shallow = true

Makefile

@@ -14,7 +14,7 @@ OBJS_EXTRA :=
 # command line option
 OPTS :=
 
-LDFLAGS := -lm
+LDFLAGS :=
 
 # virtio-blk
 ENABLE_VIRTIOBLK ?= 1
@@ -56,37 +56,61 @@ endif
 
 # virtio-snd
 ENABLE_VIRTIOSND ?= 1
-ifneq ($(UNAME_S),$(filter $(UNAME_S),Linux))
+ifneq ($(UNAME_S),$(filter $(UNAME_S),Linux Darwin))
     ENABLE_VIRTIOSND := 0
 endif
 
-# Check ALSA installation
 ifeq ($(UNAME_S),Linux)
+    # Check ALSA installation
     ifeq (0, $(call check-alsa))
         $(warning No libasound installed. Check libasound in advance.)
         ENABLE_VIRTIOSND := 0
     endif
 endif
+ifeq ($(UNAME_S),Darwin)
+    ifeq (0, $(call check-coreaudio))
+        $(warning No CoreAudio installed Check AudioToolbox in advance.)
+        ENABLE_VIRTIOSND := 0
+    endif
+endif
 $(call set-feature, VIRTIOSND)
 ifeq ($(call has, VIRTIOSND), 1)
     OBJS_EXTRA += virtio-snd.o
 
-    LDFLAGS += -lasound -lpthread
-    CFLAGS += -Icnfa
+    PORTAUDIOLIB := portaudio/lib/.libs/libportaudio.a
+    LDFLAGS += $(PORTAUDIOLIB)
 
-cnfa/Makefile:
-	git submodule update --init cnfa
-cnfa/os_generic: cnfa/Makefile
-	$(MAKE) -C $(dir $<) os_generic.h
-CNFA_LIB := cnfa/CNFA_sf.h
-$(CNFA_LIB): cnfa/Makefile cnfa/os_generic
-	$(MAKE) -C $(dir $<) CNFA_sf.h
-main.o: $(CNFA_LIB)
+    ifeq ($(UNAME_S),Linux)
+        LDFLAGS += -lasound -lrt
+        # Check PulseAudio installation
+        ifeq (0, $(call check-pa))
+            LDFLAGS += -lpulse
+        endif
+    endif
+    ifeq ($(UNAME_S),Darwin)
+        LDFLAGS += -framework CoreServices -framework CoreFoundation -framework AudioUnit -framework AudioToolbox -framework CoreAudio
+    endif
 
-# suppress warning when compiling CNFA
-virtio-snd.o: CFLAGS += -Wno-unused-parameter -Wno-sign-compare
+    CFLAGS += -Iportaudio/include
+    # PortAudio requires libm, yet we set -lm in the end of LDFLAGS
+    # so that the other libraries will be benefited for no need to set
+    # -lm separately.
+    LDFLAGS += -lpthread
+
+portaudio/Makefile:
+	git submodule update --init portaudio
+$(PORTAUDIOLIB): portaudio/Makefile
+	cd $(dir $<) && ./configure
+	$(MAKE) -C $(dir $<)
+main.o: $(PORTAUDIOLIB)
+
+# suppress warning when compiling PortAudio
+virtio-snd.o: CFLAGS += -Wno-unused-parameter
 endif
 
+# Set libm as the last dependency so that no need to set -lm seperately.
+LDFLAGS += -lm
+
 # .DEFAULT_GOAL should be set to all since the very first target is not all
 # after git submodule.
 .DEFAULT_GOAL := all

README.md

@@ -12,8 +12,8 @@ A minimalist RISC-V system emulator capable of running Linux the kernel and corr
 - Three types of I/O support using VirtIO standard:
     - virtio-blk acquires disk image from the host.
     - virtio-net is mapped as TAP interface.
-    - virtio-snd uses ALSA for sound operation with the following limitations:
-        - The emulator will hang if PulseAudio is enabled on host.
+    - virtio-snd uses PortAudio for sound operation with the following limitations:
+        - The emulator will crash after playing sound twice.
         - The playback may plays with repeating artifact.
 
 ## Prerequisites

cnfa

@@ -34,3 +34,19 @@ static inline int ilog2(int x)
 #else /* unsupported compilers */
 #define PACKED(name)
 #endif
+
+/* Pattern Matching for C macros.
+ * https://github.com/pfultz2/Cloak/wiki/C-Preprocessor-tricks,-tips,-and-idioms
+ */
+
+/* In Visual Studio, __VA_ARGS__ is treated as a separate parameter. */
+#define FIX_VC_BUG(x) x
+
+/* catenate */
+#define PRIMITIVE_CAT(a, ...) FIX_VC_BUG(a##__VA_ARGS__)
+
+#define IIF(c) PRIMITIVE_CAT(IIF_, c)
+/* run the 2nd parameter */
+#define IIF_0(t, ...) __VA_ARGS__
+/* run the 1st parameter */
+#define IIF_1(t, ...) t

common.h

@@ -941,6 +941,7 @@ CONFIG_DUMMY_CONSOLE_ROWS=25
 CONFIG_SOUND=y
 CONFIG_SND=y
 CONFIG_SND_VIRTIO=y
+CONFIG_SND_HRTIMER=y
 
 #
 # HID support

configs/linux.config

@@ -10,8 +10,41 @@ int main(){\n\
 }\n'
 endef
 
+# Create a mininal PulseAudio program
+define create-pa-prog
+echo '\
+#include <pulse/mainloop.h>\n\
+int main(){\n\
+    pa_mainloop *m;\n\
+    return 0;\n\
+}\n'
+endef
+
+# Create a mininal CoreAudio program
+define create-ca-prog
+echo '\
+#include <CoreAudio/CoreAudio.h>\n\
+#include <AudioToolbox/AudioQueue.h>
+int main(){\n\
+    AudioQueueRef queue;\n\
+    AudioQueueDispose(queue, TRUE);\n\
+    return 0;\n\
+}\n'
+endef
+
 # Check ALSA installation
 define check-alsa
 $(shell $(call create-alsa-prog) | $(CC) -x c -lasound -o /dev/null > /dev/null 2> /dev/null - 
 	&& echo $$?)
 endef
+
+# Check PulseAudio installation
+define check-pa
+$(shell $(call create-pa-prog) | $(CC) -x c -lpulse -o /dev/null - && echo 0 || echo 1)
+endef
+
+# Check CoreAudio installation
+define check-coreaudio
+$(shell $(call create-ca-prog) | $(CC) -x c -framework AudioToolbox -o /dev/null > /dev/null 2> /dev/null - 
+	&& echo $$?)
+endef

mk/check-libs.mk

@@ -37,7 +37,7 @@ function do_buildroot
 
 function do_linux
 {
-    ASSERT git clone https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git -b linux-6.1.y --depth=1
+    ASSERT git clone https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git -b linux-6.7.y --depth=1
     cp -f configs/linux.config linux/.config
     export PATH="$PWD/buildroot/output/host/bin:$PATH"
     export CROSS_COMPILE=riscv32-buildroot-linux-gnu-