From 50f11f6645072e2cf321641dbae42c356c1a4422 Mon Sep 17 00:00:00 2001
From: Mark Qvist <markq@qvistconsult.com>
Date: Fri, 4 Apr 2014 08:45:27 +0200
Subject: [PATCH] Reworked KFile read

---
 Modem/afsk.c | 26 +++++++++++++-------------
 Modem/afsk.h | 27 +++++++++++++++++++++------
 buildrev.h   |  2 +-
 3 files changed, 35 insertions(+), 20 deletions(-)

diff --git a/Modem/afsk.c b/Modem/afsk.c
index 8656c86..f8a71bc 100644
--- a/Modem/afsk.c
+++ b/Modem/afsk.c
@@ -313,18 +313,19 @@ uint8_t afsk_dac_isr(Afsk *afsk) {
 }
 
 
-
 //////////////////////////////////////////////////////
 // File operation overwrites for read/write         //
+// These functions make the "class" act like a file //
+// pointer, which can be read from or written to.   //
+// Handy for sending and receiving data :)          //
 //////////////////////////////////////////////////////
 
-static size_t afsk_read(KFile *fd, void *_buf, size_t size)
-{
-	Afsk *af = AFSK_CAST(fd);
-	uint8_t *buf = (uint8_t *)_buf;
+static size_t afsk_read(KFile *fd, void *_buf, size_t size) {
+	Afsk *afsk = AFSK_CAST(fd);
+	uint8_t *buffer = (uint8_t *)_buf;
 
 	#if CONFIG_AFSK_RXTIMEOUT == 0
-	while (size-- && !fifo_isempty_locked(&af->rxFifo))
+	while (size-- && !fifo_isempty_locked(&afsk->rxFifo))
 	#else
 	while (size--)
 	#endif
@@ -333,19 +334,18 @@ static size_t afsk_read(KFile *fd, void *_buf, size_t size)
 		ticks_t start = timer_clock();
 		#endif
 
-		while (fifo_isempty_locked(&af->rxFifo))
-		{
+		while (fifo_isempty_locked(&afsk->rxFifo)) {
 			cpu_relax();
 			#if CONFIG_AFSK_RXTIMEOUT != -1
-			if (timer_clock() - start > ms_to_ticks(CONFIG_AFSK_RXTIMEOUT))
-				return buf - (uint8_t *)_buf;
+			if (timer_clock() - start > ms_to_ticks(CONFIG_AFSK_RXTIMEOUT)) {
+				return buffer - (uint8_t *)_buf;
+			}
 			#endif
 		}
-
-		*buf++ = fifo_pop_locked(&af->rxFifo);
+		*buffer++ = fifo_pop_locked(&afsk->rxFifo);
 	}
 
-	return buf - (uint8_t *)_buf;
+	return buffer - (uint8_t *)_buf;
 }
 
 static size_t afsk_write(KFile *fd, const void *_buf, size_t size)
diff --git a/Modem/afsk.h b/Modem/afsk.h
index 2f8acd0..9801d51 100644
--- a/Modem/afsk.h
+++ b/Modem/afsk.h
@@ -71,21 +71,36 @@ typedef struct Afsk
 
 } Afsk;
 
+// Explanation nessecary for this. BertOS uses an
+// object-oriented approach for handling "file-like"
+// transactions (yes, we are using C :P). What we are
+// doing here is defining a specific "file type" for
+// the standard KFile to identify the modem as a "file"
+// that can be read from and written to.
 #define KFT_AFSK MAKE_ID('F', 'S', 'K', 'M')
 
-INLINE Afsk *AFSK_CAST(KFile *fd)
-{
+// We then make a macro that can "typecast" a generic
+// KFile file-pointer to an Afsk "object". This lets
+// other pieces of code read from and write to the AFSK
+// "objects" buffers with the standard KFile operations.
+// If this seems weird and confusing, check out the
+// BertOS KFile explanation at:
+// http://www.bertos.org/use/tutorial-front-page/drivers-kfile-interface
+INLINE Afsk *AFSK_CAST(KFile *fd) {
+  // We need to assert that the what we are trying
+  // to read/write is actually an AFSK "object",
+  // identified by the KFT_AFSK constant
   ASSERT(fd->_type == KFT_AFSK);
   return (Afsk *)fd;
 }
 
-
+// Declare ISRs and initialization functions
 void afsk_adc_isr(Afsk *af, int8_t sample);
 uint8_t afsk_dac_isr(Afsk *af);
 void afsk_init(Afsk *af, int adc_ch, int dac_ch);
 
-int afsk_testSetup(void);
-int afsk_testRun(void);
-int afsk_testTearDown(void);
+//int afsk_testSetup(void);
+//int afsk_testRun(void);
+//int afsk_testTearDown(void);
 
 #endif
diff --git a/buildrev.h b/buildrev.h
index 9cce0fd..3a49074 100644
--- a/buildrev.h
+++ b/buildrev.h
@@ -1,2 +1,2 @@
-#define VERS_BUILD 113
+#define VERS_BUILD 117
 #define VERS_HOST  "vixen"