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https://github.com/brain-hackers/u-boot-brain
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dc7100f408
We were not disabling external caches before jumping to kernel. We were flushing all caches including external caches and disabling caches globally in CP15 System Control register. Apparently this is not enough. The bootstrap loader in Linux kernel that does decompression enables data-caches again, flush them after use and disable them before jumping to kernel proper. However, it's not aware of the external caches. Since we have left external cache enabled, external cache will get used once caches are enabled globally, but it's not flushed because decompressor is not aware of external caches. When it jumps to kernel with caches disabled globally, we have stale data in the external cache and a coherency problem. This was breaking the boot for OMAP4 with latest mainline kernel. The solution is to disable external caches in cleanup_before_linux(). With this fix kernel is booting again. Cc: Albert Aribaud <albert.u.boot@aribaud.net> Signed-off-by: Aneesh V <aneesh@ti.com>
84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
/*
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* (C) Copyright 2008 Texas Insturments
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*
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* (C) Copyright 2002
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* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
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* Marius Groeger <mgroeger@sysgo.de>
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*
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* (C) Copyright 2002
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* Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* CPU specific code
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*/
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#include <common.h>
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#include <command.h>
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#include <asm/system.h>
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#include <asm/cache.h>
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#include <asm/armv7.h>
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void save_boot_params_default(u32 r0, u32 r1, u32 r2, u32 r3)
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{
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}
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void save_boot_params(u32 r0, u32 r1, u32 r2, u32 r3)
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__attribute__((weak, alias("save_boot_params_default")));
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int cleanup_before_linux(void)
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{
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/*
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* this function is called just before we call linux
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* it prepares the processor for linux
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*
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* we turn off caches etc ...
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*/
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disable_interrupts();
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/*
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* Turn off I-cache and invalidate it
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*/
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icache_disable();
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invalidate_icache_all();
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/*
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* turn off D-cache
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* dcache_disable() in turn flushes the d-cache and disables MMU
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*/
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dcache_disable();
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v7_outer_cache_disable();
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/*
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* After D-cache is flushed and before it is disabled there may
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* be some new valid entries brought into the cache. We are sure
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* that these lines are not dirty and will not affect our execution.
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* (because unwinding the call-stack and setting a bit in CP15 SCTRL
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* is all we did during this. We have not pushed anything on to the
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* stack. Neither have we affected any static data)
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* So just invalidate the entire d-cache again to avoid coherency
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* problems for kernel
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*/
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invalidate_dcache_all();
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return 0;
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}
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