340ffd267c
Add a workaround for PowerPC 440EPx/GRx incorrect write to DDR SDRAM errata. Data can be written to wrong address in SDRAM when write pipelining enabled on plb0. We disable it in the cpu_setup for these processors at early init. Signed-off-by: Valentine Barshak <vbarshak@ru.mvista.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
57 lines
1.3 KiB
ArmAsm
57 lines
1.3 KiB
ArmAsm
/*
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* This file contains low level CPU setup functions.
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* Valentine Barshak <vbarshak@ru.mvista.com>
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* MontaVista Software, Inc (c) 2007
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*
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* Based on cpu_setup_6xx code by
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* Benjamin Herrenschmidt <benh@kernel.crashing.org>
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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
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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*/
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#include <asm/processor.h>
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#include <asm/cputable.h>
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#include <asm/ppc_asm.h>
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_GLOBAL(__setup_cpu_440ep)
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b __init_fpu_44x
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_GLOBAL(__setup_cpu_440epx)
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mflr r4
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bl __init_fpu_44x
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bl __plb_disable_wrp
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mtlr r4
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blr
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_GLOBAL(__setup_cpu_440grx)
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b __plb_disable_wrp
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/* enable APU between CPU and FPU */
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_GLOBAL(__init_fpu_44x)
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mfspr r3,SPRN_CCR0
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/* Clear DAPUIB flag in CCR0 */
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rlwinm r3,r3,0,12,10
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mtspr SPRN_CCR0,r3
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isync
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blr
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/*
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* Workaround for the incorrect write to DDR SDRAM errata.
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* The write address can be corrupted during writes to
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* DDR SDRAM when write pipelining is enabled on PLB0.
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* Disable write pipelining here.
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*/
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#define DCRN_PLB4A0_ACR 0x81
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_GLOBAL(__plb_disable_wrp)
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mfdcr r3,DCRN_PLB4A0_ACR
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/* clear WRP bit in PLB4A0_ACR */
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rlwinm r3,r3,0,8,6
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mtdcr DCRN_PLB4A0_ACR,r3
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isync
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blr
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