Patchwork [U-Boot,v2] arm, arm-kirkwood: disable l2c before linux boot

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Submitter Michael Walle
Date Jan. 13, 2012, 10:53 p.m.
Message ID <1326495203-12221-1-git-send-email-michael@walle.cc>
Download mbox | patch
Permalink /patch/136029/
State Superseded
Headers show

Comments

Michael Walle - Jan. 13, 2012, 10:53 p.m.
The decompressor expects the L2 cache to be disabled. This fixes booting
some kernels, which have CONFIG_ARM_PATCH_PHYS_VIRT enabled.

Signed-off-by: Michael Walle <michael@walle.cc>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Cc: Prafulla Wadaskar <prafulla@marvell.com>
---
This is a repost, because the former had no version tag nor a history.

v2:
 - replace magic number with macro

 arch/arm/cpu/arm926ejs/cache.c           |   15 ++++++++++
 arch/arm/cpu/arm926ejs/cpu.c             |    2 +
 arch/arm/cpu/arm926ejs/kirkwood/Makefile |    1 +
 arch/arm/cpu/arm926ejs/kirkwood/cache.c  |   43 ++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 0 deletions(-)
 create mode 100644 arch/arm/cpu/arm926ejs/kirkwood/cache.c
Michael Walle - Jan. 13, 2012, 10:59 p.m.
[Sorry can't answer to the original message, because it was blocked by spam 
filter]

> Also, I'm missing something: you introduce two functions, for enabling 
> and disabling the cache, yet the code uses only the one for disabling. 
> So what enabled it in the first place?
The L2C is enabled in arch_misc_init() in
   arch/arm/cpu/arm926ejs/kirkwood/cpu.c

My enable function is just for completeness atm.
Michael Walle - Jan. 31, 2012, 10:49 p.m.
Am Freitag 13 Januar 2012, 23:59:08 schrieb Michael Walle:
> [Sorry can't answer to the original message, because it was blocked by spam
> filter]
> 
> > Also, I'm missing something: you introduce two functions, for enabling
> > and disabling the cache, yet the code uses only the one for disabling.
> > So what enabled it in the first place?
> 
> The L2C is enabled in arch_misc_init() in
>    arch/arm/cpu/arm926ejs/kirkwood/cpu.c
> 
> My enable function is just for completeness atm.

Ping.

Is there something still uncertain?
Wolfgang Denk - Jan. 31, 2012, 11:04 p.m.
Dear Michael Walle,

In message <201201312349.37621.michael@walle.cc> you wrote:
>
> > My enable function is just for completeness atm.
> 
> Ping.
> 
> Is there something still uncertain?

Nothing is uncertain.

But we do not add dead code.

Best regards,

Wolfgang Denk

Patch

diff --git a/arch/arm/cpu/arm926ejs/cache.c b/arch/arm/cpu/arm926ejs/cache.c
index ee90ab7..ba13154 100644
--- a/arch/arm/cpu/arm926ejs/cache.c
+++ b/arch/arm/cpu/arm926ejs/cache.c
@@ -68,3 +68,18 @@  void  flush_cache(unsigned long start, unsigned long size)
 {
 }
 #endif /* #ifndef CONFIG_SYS_DCACHE_OFF */
+
+/*
+ * Stub implementations for l2 cache operations
+ */
+void __l2_cache_enable(void)
+{
+}
+void l2_cache_enable(void)
+        __attribute__((weak, alias("__l2_cache_enable")));
+
+void __l2_cache_disable(void)
+{
+}
+void l2_cache_disable(void)
+        __attribute__((weak, alias("__l2_cache_disable")));
diff --git a/arch/arm/cpu/arm926ejs/cpu.c b/arch/arm/cpu/arm926ejs/cpu.c
index 5c902df..626384c 100644
--- a/arch/arm/cpu/arm926ejs/cpu.c
+++ b/arch/arm/cpu/arm926ejs/cpu.c
@@ -50,6 +50,8 @@  int cleanup_before_linux (void)
 	/* turn off I/D-cache */
 	icache_disable();
 	dcache_disable();
+	l2_cache_disable();
+
 	/* flush I/D-cache */
 	cache_flush();
 
diff --git a/arch/arm/cpu/arm926ejs/kirkwood/Makefile b/arch/arm/cpu/arm926ejs/kirkwood/Makefile
index 0754297..777006c 100644
--- a/arch/arm/cpu/arm926ejs/kirkwood/Makefile
+++ b/arch/arm/cpu/arm926ejs/kirkwood/Makefile
@@ -30,6 +30,7 @@  COBJS-y	= cpu.o
 COBJS-y	+= dram.o
 COBJS-y	+= mpp.o
 COBJS-y	+= timer.o
+COBJS-y	+= cache.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS-y))
diff --git a/arch/arm/cpu/arm926ejs/kirkwood/cache.c b/arch/arm/cpu/arm926ejs/kirkwood/cache.c
new file mode 100644
index 0000000..df90cb9
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/kirkwood/cache.c
@@ -0,0 +1,43 @@ 
+/*
+ * Copyright (c) 2011 Michael Walle
+ * Michael Walle <michael@walle.cc>
+ *
+ * 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.
+ */
+#include <common.h>
+#include <asm/arch/cpu.h>
+
+#define FEROCEON_EXTRA_FEATURE_L2C_EN (1<<22)
+
+void l2_cache_enable()
+{
+	u32 ctrl;
+
+	ctrl = readfr_extra_feature_reg();
+	ctrl |= FEROCEON_EXTRA_FEATURE_L2C_EN;
+	writefr_extra_feature_reg(ctrl);
+}
+
+void l2_cache_disable()
+{
+	u32 ctrl;
+
+	ctrl = readfr_extra_feature_reg();
+	ctrl &= ~FEROCEON_EXTRA_FEATURE_L2C_EN;
+	writefr_extra_feature_reg(ctrl);
+}