basecmd: Avoid calling malloc() from main code

Introduce a new board function alloc_chunk() to allocate dynamic
memory.  This allows the board code to implement memory allocations
without using the standard malloc() interface.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 27 insertions, 10 deletions

diff --git a/src/avr/misc.c b/src/avr/misc.c
index 682ef29d..9740a806 100644
--- a/src/avr/misc.c
+++ b/src/avr/misc.c
@@ -1,15 +1,18 @@
 // AVR miscellaneous platform code
 //
-// Copyright (C) 2016  Kevin O'Connor <kevin@koconnor.net>
+// Copyright (C) 2016,2017  Kevin O'Connor <kevin@koconnor.net>
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
 #include <avr/io.h> // AVR_STACK_POINTER_REG
 #include <stdlib.h> // __malloc_heap_end
+#include <string.h> // memset
 #include <util/crc16.h> // _crc_ccitt_update
 #include "autoconf.h" // CONFIG_AVR_STACK_SIZE
 #include "board/misc.h" // alloc_maxsize
+#include "command.h" // shutdown
 #include "compiler.h" // ALIGN
+#include "sched.h" // sched_shutdown
 
 // Optimized crc16_ccitt for the avr processor
 uint16_t
@@ -21,17 +24,31 @@ crc16_ccitt(char *buf, uint8_t len)
     return crc;
 }
 
-// Return the maximum allocation size that can succeed up to 'reqsize'
-size_t
-alloc_maxsize(size_t reqsize)
+// Allocate an area of memory
+void *
+alloc_chunk(size_t size)
+{
+    void *data = malloc(size);
+    if (!data)
+        shutdown("alloc_chunk failed");
+    memset(data, 0, size);
+    return data;
+}
+
+// Allocate an array of chunks
+void *
+alloc_chunks(size_t size, size_t count, size_t *avail)
 {
     uint16_t memend = ALIGN(AVR_STACK_POINTER_REG, 256);
     __malloc_heap_end = (void*)memend - CONFIG_AVR_STACK_SIZE;
     extern char *__brkval;
-    int16_t maxsize = __malloc_heap_end - __brkval - 2;
-    if (maxsize < 0)
-        return 0;
-    if (reqsize < maxsize)
-        return reqsize;
-    return maxsize;
+    uint16_t maxsize = __malloc_heap_end - __brkval - 2;
+    if ((int16_t)maxsize < 0)
+        maxsize = 0;
+    if (count * size > maxsize)
+        count = maxsize / size;
+    if (!count)
+        shutdown("alloc_chunks failed");
+    *avail = count;
+    return alloc_chunk(count * size);
 }