o start usb uploadr avr

poc/avr_usbload/fifo.c

@@ -0,0 +1,28 @@
+#include "fifo.h"
+
+void fifo_init(fifo_t * f, uint8_t * buffer, const uint8_t size)
+{
+    f->count = 0;
+    f->pread = f->pwrite = buffer;
+    f->read2end = f->write2end = f->size = size;
+}
+
+uint8_t fifo_put(fifo_t * f, const uint8_t data)
+{
+    return _inline_fifo_put(f, data);
+}
+
+uint8_t fifo_get_wait(fifo_t * f)
+{
+    while (!f->count);
+
+    return _inline_fifo_get(f);
+}
+
+int fifo_get_nowait(fifo_t * f)
+{
+    if (!f->count)
+        return -1;
+
+    return (int) _inline_fifo_get(f);
+}