linux-kernel - [PATCH 24/43] MN10300: Make the boot wrapper able to use writeback caching

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Date:	Tue, 26 Oct 2010 03:55:09 +0100
From:	David Howells <dhowells@...hat.com>
To:	linux-am33-list@...hat.com
Cc:	linux-kernel@...r.kernel.org,
	Akira Takeuchi <takeuchi.akr@...panasonic.com>,
	Kiyoshi Owada <owada.kiyoshi@...panasonic.com>
Subject: [PATCH 24/43] MN10300: Make the boot wrapper able to use writeback
 caching

From: Akira Takeuchi <takeuchi.akr@...panasonic.com>

Make the boot wrapper able to use writeback caching, including flushing the
cache before jumping to the main kernel.

Signed-off-by: Akira Takeuchi <takeuchi.akr@...panasonic.com>
Signed-off-by: Kiyoshi Owada <owada.kiyoshi@...panasonic.com>
Signed-off-by: David Howells <dhowells@...hat.com>
---

 arch/mn10300/boot/compressed/head.S |   49 ++++++++++++++++++++++++++++++++++-
 1 files changed, 48 insertions(+), 1 deletions(-)


diff --git a/arch/mn10300/boot/compressed/head.S b/arch/mn10300/boot/compressed/head.S
index 502e1eb..4ef608a 100644
--- a/arch/mn10300/boot/compressed/head.S
+++ b/arch/mn10300/boot/compressed/head.S
@@ -14,6 +14,7 @@
 
 #include <linux/linkage.h>
 #include <asm/cpu-regs.h>
+#include <asm/cache.h>
 
 	.globl startup_32
 startup_32:
@@ -37,8 +38,15 @@ startup_32:
 	mov	(a0),d0
 	btst	CHCTR_ICBUSY|CHCTR_DCBUSY,d0		# wait till not busy
 	lne
-	mov	CHCTR_ICEN|CHCTR_DCEN|CHCTR_DCWTMD,d0	# writethru dcache
+
+#ifdef CONFIG_MN10300_CACHE_ENABLED
+#ifdef CONFIG_MN10300_CACHE_WBACK
+	mov	CHCTR_ICEN|CHCTR_DCEN|CHCTR_DCWTMD_WRBACK,d0
+#else
+	mov	CHCTR_ICEN|CHCTR_DCEN|CHCTR_DCWTMD_WRTHROUGH,d0
+#endif /* WBACK */
 	movhu	d0,(a0)					# enable
+#endif /* !ENABLED */
 
 	# clear the BSS area
 	mov	__bss_start,a0
@@ -54,6 +62,9 @@ bssclear_end:
 
 	# decompress the kernel
 	call	decompress_kernel[],0
+#ifdef CONFIG_MN10300_CACHE_WBACK
+	call	mn10300_dcache_flush_inv[],0
+#endif
 
 	# disable caches again
 	mov	CHCTR,a0
@@ -69,10 +80,46 @@ bssclear_end:
 	mov	(4,a0),d1
 	mov	(8,a0),d2
 
+	# jump to the kernel proper entry point
 	mov	a3,sp
 	mov	CONFIG_KERNEL_TEXT_ADDRESS,a0
 	jmp	(a0)
 
+
+###############################################################################
+#
+# Cache flush routines
+#
+###############################################################################
+#ifdef CONFIG_MN10300_CACHE_WBACK
+mn10300_dcache_flush_inv:
+	movhu	(CHCTR),d0
+	btst	CHCTR_DCEN,d0
+	beq	mn10300_dcache_flush_inv_end
+
+	mov	L1_CACHE_NENTRIES,d1
+	clr	a1
+
+mn10300_dcache_flush_inv_loop:
+	mov	(DCACHE_PURGE_WAY0(0),a1),d0	# unconditional purge
+	mov	(DCACHE_PURGE_WAY1(0),a1),d0	# unconditional purge
+	mov	(DCACHE_PURGE_WAY2(0),a1),d0	# unconditional purge
+	mov	(DCACHE_PURGE_WAY3(0),a1),d0	# unconditional purge
+
+	add	L1_CACHE_BYTES,a1
+	add	-1,d1
+	bne	mn10300_dcache_flush_inv_loop
+
+mn10300_dcache_flush_inv_end:
+	ret	[],0
+#endif /* CONFIG_MN10300_CACHE_WBACK */
+
+
+###############################################################################
+#
+# Data areas
+#
+###############################################################################
 	.data
 	.align		4
 param_save_area:

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