summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/boot/simple_alloc.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/boot/simple_alloc.c')
-rw-r--r--arch/powerpc/boot/simple_alloc.c150
1 files changed, 150 insertions, 0 deletions
diff --git a/arch/powerpc/boot/simple_alloc.c b/arch/powerpc/boot/simple_alloc.c
new file mode 100644
index 000000000..65ec135d0
--- /dev/null
+++ b/arch/powerpc/boot/simple_alloc.c
@@ -0,0 +1,150 @@
+/*
+ * Implement primitive realloc(3) functionality.
+ *
+ * Author: Mark A. Greer <mgreer@mvista.com>
+ *
+ * 2006 (c) MontaVista, Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+
+#include <stddef.h>
+#include "types.h"
+#include "page.h"
+#include "string.h"
+#include "ops.h"
+
+#define ENTRY_BEEN_USED 0x01
+#define ENTRY_IN_USE 0x02
+
+static struct alloc_info {
+ unsigned long flags;
+ unsigned long base;
+ unsigned long size;
+} *alloc_tbl;
+
+static unsigned long tbl_entries;
+static unsigned long alloc_min;
+static unsigned long next_base;
+static unsigned long space_left;
+
+/*
+ * First time an entry is used, its base and size are set.
+ * An entry can be freed and re-malloc'd but its base & size don't change.
+ * Should be smart enough for needs of bootwrapper.
+ */
+static void *simple_malloc(unsigned long size)
+{
+ unsigned long i;
+ struct alloc_info *p = alloc_tbl;
+
+ if (size == 0)
+ goto err_out;
+
+ size = _ALIGN_UP(size, alloc_min);
+
+ for (i=0; i<tbl_entries; i++, p++)
+ if (!(p->flags & ENTRY_BEEN_USED)) { /* never been used */
+ if (size <= space_left) {
+ p->base = next_base;
+ p->size = size;
+ p->flags = ENTRY_BEEN_USED | ENTRY_IN_USE;
+ next_base += size;
+ space_left -= size;
+ return (void *)p->base;
+ }
+ goto err_out; /* not enough space left */
+ }
+ /* reuse an entry keeping same base & size */
+ else if (!(p->flags & ENTRY_IN_USE) && (size <= p->size)) {
+ p->flags |= ENTRY_IN_USE;
+ return (void *)p->base;
+ }
+err_out:
+ return NULL;
+}
+
+static struct alloc_info *simple_find_entry(void *ptr)
+{
+ unsigned long i;
+ struct alloc_info *p = alloc_tbl;
+
+ for (i=0; i<tbl_entries; i++,p++) {
+ if (!(p->flags & ENTRY_BEEN_USED))
+ break;
+ if ((p->flags & ENTRY_IN_USE) &&
+ (p->base == (unsigned long)ptr))
+ return p;
+ }
+ return NULL;
+}
+
+static void simple_free(void *ptr)
+{
+ struct alloc_info *p = simple_find_entry(ptr);
+
+ if (p != NULL)
+ p->flags &= ~ENTRY_IN_USE;
+}
+
+/*
+ * Change size of area pointed to by 'ptr' to 'size'.
+ * If 'ptr' is NULL, then its a malloc(). If 'size' is 0, then its a free().
+ * 'ptr' must be NULL or a pointer to a non-freed area previously returned by
+ * simple_realloc() or simple_malloc().
+ */
+static void *simple_realloc(void *ptr, unsigned long size)
+{
+ struct alloc_info *p;
+ void *new;
+
+ if (size == 0) {
+ simple_free(ptr);
+ return NULL;
+ }
+
+ if (ptr == NULL)
+ return simple_malloc(size);
+
+ p = simple_find_entry(ptr);
+ if (p == NULL) /* ptr not from simple_malloc/simple_realloc */
+ return NULL;
+ if (size <= p->size) /* fits in current block */
+ return ptr;
+
+ new = simple_malloc(size);
+ memcpy(new, ptr, p->size);
+ simple_free(ptr);
+ return new;
+}
+
+/*
+ * Returns addr of first byte after heap so caller can see if it took
+ * too much space. If so, change args & try again.
+ */
+void *simple_alloc_init(char *base, unsigned long heap_size,
+ unsigned long granularity, unsigned long max_allocs)
+{
+ unsigned long heap_base, tbl_size;
+
+ heap_size = _ALIGN_UP(heap_size, granularity);
+ alloc_min = granularity;
+ tbl_entries = max_allocs;
+
+ tbl_size = tbl_entries * sizeof(struct alloc_info);
+
+ alloc_tbl = (struct alloc_info *)_ALIGN_UP((unsigned long)base, 8);
+ memset(alloc_tbl, 0, tbl_size);
+
+ heap_base = _ALIGN_UP((unsigned long)alloc_tbl + tbl_size, alloc_min);
+
+ next_base = heap_base;
+ space_left = heap_size;
+
+ platform_ops.malloc = simple_malloc;
+ platform_ops.free = simple_free;
+ platform_ops.realloc = simple_realloc;
+
+ return (void *)(heap_base + heap_size);
+}