This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / powerpc / boot / simple_alloc.c

diff --git a/arch/powerpc/boot/simple_alloc.c b/arch/powerpc/boot/simple_alloc.c
new file mode 100644 (file)
index 0000000..cfe3a75
--- /dev/null
+++ b/arch/powerpc/boot/simple_alloc.c
@@ -0,0 +1,149 @@
+/*
+ * 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 {
+       u32     flags;
+       u32     base;
+       u32     size;
+} *alloc_tbl;
+
+static u32 tbl_entries;
+static u32 alloc_min;
+static u32 next_base;
+static u32 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(u32 size)
+{
+       u32 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)
+{
+       u32 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 == (u32)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, u32 heap_size, u32 granularity,
+               u32 max_allocs)
+{
+       u32 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((u32)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);
+}