From: Haavard Skinnemoen <hskinnemoen@atmel.com>
Date: Mon, 11 Jun 2007 15:17:14 +0000 (+0200)
Subject: [AVR32] Define ARCH_KMALLOC_MINALIGN to L1_CACHE_BYTES
X-Git-Tag: v2.6.22-rc5~31^2
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=093d0faf57e59feee224217273f944e10e4e3562;p=linux-2.6

[AVR32] Define ARCH_KMALLOC_MINALIGN to L1_CACHE_BYTES

This allows SLUB debugging to be used without fear of messing up DMA
transfers. SPI is one example that easily breaks without this patch.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
---

diff --git a/include/asm-avr32/cache.h b/include/asm-avr32/cache.h
index dabb955f3c..d3cf35ab11 100644
--- a/include/asm-avr32/cache.h
+++ b/include/asm-avr32/cache.h
@@ -4,6 +4,15 @@
 #define L1_CACHE_SHIFT 5
 #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
 
+/*
+ * Memory returned by kmalloc() may be used for DMA, so we must make
+ * sure that all such allocations are cache aligned. Otherwise,
+ * unrelated code may cause parts of the buffer to be read into the
+ * cache before the transfer is done, causing old data to be seen by
+ * the CPU.
+ */
+#define ARCH_KMALLOC_MINALIGN	L1_CACHE_BYTES
+
 #ifndef __ASSEMBLER__
 struct cache_info {
 	unsigned int ways;