d9b55a0361
This adds support for early serial debugging via the built in port on IBM/AMCC PowerPC 44x CPUs. It uses a bolted TLB entry in address space 1 for the UART's mapping, allowing robust debugging both before and after the initialization of the MMU. Signed-off-by: David Gibson <dwg@au1.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
57 lines
1,005 B
ArmAsm
57 lines
1,005 B
ArmAsm
/*
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* This file contains miscellaneous low-level functions for PPC 44x.
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* Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
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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/reg.h>
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#include <asm/ppc_asm.h>
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.text
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/*
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* Do an IO access in AS1
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*/
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_GLOBAL(as1_readb)
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mfmsr r7
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ori r0,r7,MSR_DS
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sync
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mtmsr r0
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sync
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isync
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lbz r3,0(r3)
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sync
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mtmsr r7
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sync
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isync
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blr
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_GLOBAL(as1_writeb)
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mfmsr r7
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ori r0,r7,MSR_DS
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sync
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mtmsr r0
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sync
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isync
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stb r3,0(r4)
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sync
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mtmsr r7
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sync
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isync
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blr
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/*
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* void ppc44x_reset_system(char *cmd)
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*
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* At present, this routine just applies a system reset.
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*/
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_GLOBAL(ppc44x_reset_system)
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mfspr r13,SPRN_DBCR0
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oris r13,r13,DBCR0_RST_SYSTEM@h
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mtspr SPRN_DBCR0,r13
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b . /* Just in case the reset doesn't work */
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