From 2e14faeef6caf05fd8de603d4fbb45e765b31e6a Mon Sep 17 00:00:00 2001
From: Nicholas Sherlock <n.sherlock@gmail.com>
Date: Wed, 28 Jan 2015 20:48:06 +1300
Subject: [PATCH] Comment updates, allow CLI flash read to read more in one
 operation

---
 src/main/drivers/flash_m25p16.c |  6 +++++-
 src/main/io/flashfs.c           | 11 +++++------
 src/main/io/serial_cli.c        | 20 +++++++++++---------
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/src/main/drivers/flash_m25p16.c b/src/main/drivers/flash_m25p16.c
index 864eacd77..3eac01041 100644
--- a/src/main/drivers/flash_m25p16.c
+++ b/src/main/drivers/flash_m25p16.c
@@ -97,6 +97,7 @@ static uint8_t m25p16_readStatus()
 
 bool m25p16_isReady()
 {
+    // If couldBeBusy is false, don't bother to poll the flash chip for its status
     couldBeBusy = couldBeBusy && ((m25p16_readStatus() & M25P16_STATUS_FLAG_WRITE_IN_PROGRESS) != 0);
 
     return !couldBeBusy;
@@ -126,7 +127,10 @@ static bool m25p16_readIdentification()
 
     delay(50); // short delay required after initialisation of SPI device instance.
 
-    in[1] = 0; // Just in case transfer fails and writes nothing
+    /* Just in case transfer fails and writes nothing, so we don't try to verify the ID against random garbage
+     * from the stack:
+     */
+    in[1] = 0;
 
     ENABLE_M25P16;
 
diff --git a/src/main/io/flashfs.c b/src/main/io/flashfs.c
index 3a6795ff1..015738eb3 100644
--- a/src/main/io/flashfs.c
+++ b/src/main/io/flashfs.c
@@ -114,15 +114,11 @@ static uint32_t flashfsTransmitBufferUsed()
 
 static uint32_t flashfsTransmitBufferRemaining()
 {
-    /*
-     * We subtract one from the actual transmit buffer remaining space to allow us to distinguish
-     * between completely full and completely empty states, that would otherwise both have head = tail
-     */
     return FLASHFS_WRITE_BUFFER_USABLE - flashfsTransmitBufferUsed();
 }
 
 /**
- * Waits for the flash device to be ready to accept writes, then write the given buffers to flash.
+ * Waits for the flash device to be ready to accept writes, then write the given buffers to flash sequentially.
  *
  * Advances the address of the beginning of the supplied buffers and reduces the size of the buffers according to how
  * many bytes get written.
@@ -150,7 +146,10 @@ static void flashfsWriteBuffers(uint8_t const **buffers, uint32_t *bufferSizes,
         uint32_t bytesTotalThisIteration;
         uint32_t bytesRemainThisIteration;
 
-        // If we would cross a page boundary, only write up to the boundary in this iteration:
+        /*
+         * Each page needs to be saved in a separate program operation, so
+         * if we would cross a page boundary, only write up to the boundary in this iteration:
+         */
         if (tailIndexInPage + bytesTotalRemaining > geometry->pageSize) {
             bytesTotalThisIteration = geometry->pageSize - tailIndexInPage;
         } else {
diff --git a/src/main/io/serial_cli.c b/src/main/io/serial_cli.c
index 66aaf3464..c4e010cc5 100644
--- a/src/main/io/serial_cli.c
+++ b/src/main/io/serial_cli.c
@@ -44,7 +44,6 @@
 #include "drivers/gpio.h"
 #include "drivers/timer.h"
 #include "drivers/pwm_rx.h"
-#include "drivers/flash_m25p16.h"
 #include "flight/flight.h"
 #include "flight/mixer.h"
 #include "flight/navigation.h"
@@ -794,18 +793,21 @@ static void cliFlashRead(char *cmdline)
         printf("Missing length argument.\r\n");
     } else {
         length = atoi(nextArg);
-        if (length > 32) {
-            length = 32;
-            printf("Length truncated to 32 bytes.\r\n");
-        }
+
+        printf("Reading %u bytes at %u:\r\n", length, address);
 
         flashfsSeekAbs(address);
-        flashfsRead(buffer, length);
 
-        printf("Read %u bytes at %u:\r\n", length, address);
+        while (length > 0) {
+            int bytesToRead = length < 32 ? length : 32;
 
-        for (i = 0; i < length; i++) {
-            printf("%c", (char) buffer[i]);
+            flashfsRead(buffer, bytesToRead);
+
+            for (i = 0; i < bytesToRead; i++) {
+                printf("%c", (char) buffer[i]);
+            }
+
+            length -= bytesToRead;
         }
         printf("\r\n");
     }