Add refcounting to nvidia stuff

nx/include/switch/nvidia/buffer.h

@@ -249,8 +249,8 @@ typedef enum {
     NvBufferKind_Invalid=0xff,
 } NvBufferKind;
 
-Result nvbufInit();
-Result nvbufExit();
+Result nvbufInit(void);
+void nvbufExit(void);
 
 Result nvbufCreate(NvBuffer* m, size_t size, u32 align, NvBufferKind kind);
 Result nvbufCreateRw(NvBuffer* m, size_t size, u32 align, NvBufferKind kind);

nx/source/nvidia/buffer.c

@@ -1,18 +1,38 @@
 #include <malloc.h>
 #include "types.h"
 #include "result.h"
+#include "arm/atomics.h"
 #include "services/nv.h"
 #include "nvidia/ioctl.h"
 #include "nvidia/buffer.h"
 
-static u32 g_nvmap_fd;
+static u32 g_nvmap_fd = -1;
+static u64 g_refCnt;
 
-Result nvbufInit() {
-    return nvOpen(&g_nvmap_fd, "/dev/nvmap");
+Result nvbufInit(void)
+{
+    Result rc;
+
+    if (atomicIncrement64(&g_refCnt) > 0)
+        return 0;
+
+     rc = nvOpen(&g_nvmap_fd, "/dev/nvmap");
+
+     if (R_FAILED(rc))
+         atomicDecrement64(&g_refCnt);
+
+     return rc;
 }
 
-Result nvbufExit() {
-    return nvClose(g_nvmap_fd);
+void nvbufExit(void)
+{
+    if (atomicDecrement64(&g_refCnt) == 0)
+    {
+        if (g_nvmap_fd != -1)
+            nvClose(g_nvmap_fd);
+
+        g_nvmap_fd = -1;
+    }
 }
 
 static Result _nvbufCreate(NvBuffer* m, size_t size, u32 flags, u32 align, NvBufferKind kind)

nx/source/nvidia/info.c

@@ -1,6 +1,8 @@
 #include <switch.h>
 
 static u32 g_ctrlgpu_fd = -1;
+static u64 g_refCnt;
+
 static nvioctl_gpu_characteristics g_gpu_characteristics;
 static u32 g_zcull_ctx_size;
 
@@ -8,6 +10,9 @@ Result nvinfoInit()
 {
     Result rc;
 
+    if (atomicIncrement64(&g_refCnt) > 0)
+        return 0;
+
     rc = nvOpen(&g_ctrlgpu_fd, "/dev/nvhost-ctrl-gpu");
 
     if (R_FAILED(rc))
@@ -27,10 +32,13 @@ Result nvinfoInit()
 
 void nvinfoExit()
 {
-    if (g_ctrlgpu_fd != -1)
-        nvClose(g_ctrlgpu_fd);
+    if (atomicDecrement64(&g_refCnt) == 0)
+    {
+        if (g_ctrlgpu_fd != -1)
+            nvClose(g_ctrlgpu_fd);
 
-    g_ctrlgpu_fd = -1;
+        g_ctrlgpu_fd = -1;
+    }
 }
 
 u32 nvinfoGetZcullCtxSize() {