avr32: cache: define ARCH_DMA_MINALIGN for DMA buffer alignment

Signed-off-by: Anton Staaf <robotboy@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Reinhard Meyer <u-boot@emk-elektronik.de>

arch/avr32/include/asm/cache.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2011 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#ifndef __AVR32_CACHE_H__
+#define __AVR32_CACHE_H__
+
+/*
+ * Since the AVR32 architecture has a queryable cacheline size with a maximum
+ * value of 256 we set the DMA buffer alignemnt requirement to this maximum
+ * value.  The board config can override this if it knows that the cacheline
+ * size is a smaller value.  AVR32 boards use the CONFIG_SYS_DCACHE_LINESZ
+ * macro to specify cache line size, so if it is set we use it instead.
+ */
+#ifdef CONFIG_SYS_CACHELINE_SIZE
+#define ARCH_DMA_MINALIGN	CONFIG_SYS_CACHELINE_SIZE
+#elif defined(CONFIG_SYS_DCACHE_LINESZ)
+#define ARCH_DMA_MINALIGN	CONFIG_SYS_DCACHE_LINESZ
+#else
+#define ARCH_DMA_MINALIGN	256
+#endif
+
+#endif /* __AVR32_CACHE_H__ */