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>

src/generic/alloc.c

@@ -1,13 +1,37 @@
 // Dummy implementation for alloc commands
 //
-// 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 "misc.h"
+#include <stdlib.h> // malloc
+#include <string.h> // memset
+#include "command.h" // shutdown
+#include "misc.h" // alloc_chunk
+#include "sched.h" // sched_shutdown
 
 // Return the maximum allocation size that can succeed up to 'reqsize'
-size_t alloc_maxsize(size_t reqsize)
+size_t
+alloc_chunk_maxsize(size_t reqsize)
 {
     return 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)
+{
+    *avail = count;
+    return alloc_chunk(size * count);
+}