war.h
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上传日期:2013-04-10
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- /*
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 2002 by Ralf Baechle
- */
- #ifndef _ASM_WAR_H
- #define _ASM_WAR_H
- #include <linux/config.h>
- /*
- * Pleassures of the R4600 V1.x. Cite from the IDT R4600 V1.7 errata:
- *
- * 18. The CACHE instructions Hit_Writeback_Invalidate_D, Hit_Writeback_D,
- * Hit_Invalidate_D and Create_Dirty_Excl_D should only be
- * executed if there is no other dcache activity. If the dcache is
- * accessed for another instruction immeidately preceding when these
- * cache instructions are executing, it is possible that the dcache
- * tag match outputs used by these cache instructions will be
- * incorrect. These cache instructions should be preceded by at least
- * four instructions that are not any kind of load or store
- * instruction.
- *
- * This is not allowed: lw
- * nop
- * nop
- * nop
- * cache Hit_Writeback_Invalidate_D
- *
- * This is allowed: lw
- * nop
- * nop
- * nop
- * nop
- * cache Hit_Writeback_Invalidate_D
- */
- #define R4600_V1_HIT_DCACHE_WAR
- /*
- * Writeback and invalidate the primary cache dcache before DMA.
- *
- * R4600 v2.0 bug: "The CACHE instructions Hit_Writeback_Inv_D,
- * Hit_Writeback_D, Hit_Invalidate_D and Create_Dirty_Exclusive_D will only
- * operate correctly if the internal data cache refill buffer is empty. These
- * CACHE instructions should be separated from any potential data cache miss
- * by a load instruction to an uncached address to empty the response buffer."
- * (Revision 2.0 device errata from IDT available on http://www.idt.com/
- * in .pdf format.)
- */
- #define R4600_V2_HIT_CACHEOP_WAR
- #ifdef CONFIG_CPU_R5432
- /*
- * When an interrupt happens on a CP0 register read instruction, CPU may
- * lock up or read corrupted values of CP0 registers after it enters
- * the exception handler.
- *
- * This workaround makes sure that we read a "safe" CP0 register as the
- * first thing in the exception handler, which breaks one of the
- * pre-conditions for this problem.
- */
- #define R5432_CP0_INTERRUPT_WAR
- #endif
- #endif /* _ASM_WAR_H */