[U-Boot] [PATCH v4] dcache: D cache line size read method

[Lukasz Majewski]

The get_dcache_line_size() function is supposed to work in conjunction
with memalign call to provide D cache aligned DMA buffers.

This commit adds support for reading the D cache line size for armv7
architecture. Moreover a default implementation of get_dcache_line_size()
is provided.

Signed-off-by: Lukasz Majewski <l.majewski at samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
CC: Aneesh V <aneesh at ti.com>
CC: Albert ARIBAUD <albert.u.boot at aribaud.net>
---
Changes for v2:
- Weak function get_dcache_line_size added to arch/arm/lib/cache.c
Changes for v3:
- __BIGGEST_ALIGNMENT__ GCC constant added
Changes for v4:
- Weak function get_dcache_line_size added to arch/arm/lib/cache.c for non armv7
architectures
---
 arch/arm/cpu/armv7/cache_v7.c |   14 ++++++++++++++
 include/common.h              |    1 +
 lib/Makefile                  |    1 +
 lib/cache.c                   |   34 ++++++++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 0 deletions(-)
 create mode 100644 lib/cache.c

diff --git a/arch/arm/cpu/armv7/cache_v7.c b/arch/arm/cpu/armv7/cache_v7.c
index 3e1e1bf..ea5a3e4 100644
--- a/arch/arm/cpu/armv7/cache_v7.c
+++ b/arch/arm/cpu/armv7/cache_v7.c
@@ -246,6 +246,20 @@ static void v7_inval_tlb(void)
 	CP15ISB;
 }
 
+/* Read the cache line size (in bytes) */
+int get_dcache_line_size(void)
+{
+	u32 ccsidr, log2_line_len;
+
+	ccsidr = get_ccsidr();
+	log2_line_len = ((ccsidr & CCSIDR_LINE_SIZE_MASK) >>
+				CCSIDR_LINE_SIZE_OFFSET) + 2;
+	/* Converting from words to bytes */
+	log2_line_len += 2;
+
+	return 1 << log2_line_len;
+}
+
 void invalidate_dcache_all(void)
 {
 	v7_maint_dcache_all(ARMV7_DCACHE_INVAL_ALL);
diff --git a/include/common.h b/include/common.h
index 12a1074..b535300 100644
--- a/include/common.h
+++ b/include/common.h
@@ -622,6 +622,7 @@ void	flush_dcache_range(unsigned long start, unsigned long stop);
 void	invalidate_dcache_range(unsigned long start, unsigned long stop);
 void	invalidate_dcache_all(void);
 void	invalidate_icache_all(void);
+int     get_dcache_line_size(void);
 
 /* arch/$(ARCH)/lib/ticks.S */
 unsigned long long get_ticks(void);
diff --git a/lib/Makefile b/lib/Makefile
index 884f64c..c0070c2 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -49,6 +49,7 @@ COBJS-$(CONFIG_SHA1) += sha1.o
 COBJS-$(CONFIG_SHA256) += sha256.o
 COBJS-y	+= strmhz.o
 COBJS-$(CONFIG_RBTREE)	+= rbtree.o
+COBJS-y	+= cache.o
 endif
 
 COBJS-y += ctype.o
diff --git a/lib/cache.c b/lib/cache.c
new file mode 100644
index 0000000..b8f49ce
--- /dev/null
+++ b/lib/cache.c
@@ -0,0 +1,34 @@
+/*
+ * (C) Copyright 2011 SAMSUNG Electronics
+ * Łukasz Majewski <l.majewski at samsung.com>
+ *
+ * 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
+ */
+
+#include <common.h>
+
+/* Read the default Data CACHE LINE size */
+int __attribute__((weak)) get_dcache_line_size(void)
+{
+#if defined(CONFIG_SYS_CACHE_LINE_SIZE) && !defined(CONFIG_SYS_DCACHE_OFF)
+	return CONFIG_SYS_CACHE_LINE_SIZE;
+#else
+	return __BIGGEST_ALIGNMENT__;  /* Constant defined by GCC compiler */
+#endif
+}
-- 
1.7.2.3