/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Paul Burton <paul.burton@mips.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <asm/addrspace.h>
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#include <asm/asm.h>
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#include <asm/asm-offsets.h>
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#include <asm/mipsregs.h>
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#include <asm/regdef.h>
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#include <linux/serial_reg.h>
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#define UART_TX_OFS (UART_TX << CONFIG_MIPS_CPS_NS16550_SHIFT)
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#define UART_LSR_OFS (UART_LSR << CONFIG_MIPS_CPS_NS16550_SHIFT)
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/**
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* _mips_cps_putc() - write a character to the UART
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* @a0: ASCII character to write
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* @t9: UART base address
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*/
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LEAF(_mips_cps_putc)
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1: lw t0, UART_LSR_OFS(t9)
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andi t0, t0, UART_LSR_TEMT
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beqz t0, 1b
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sb a0, UART_TX_OFS(t9)
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jr ra
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END(_mips_cps_putc)
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/**
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* _mips_cps_puts() - write a string to the UART
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* @a0: pointer to NULL-terminated ASCII string
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* @t9: UART base address
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*
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* Write a null-terminated ASCII string to the UART.
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*/
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NESTED(_mips_cps_puts, 0, ra)
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move s7, ra
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move s6, a0
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1: lb a0, 0(s6)
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beqz a0, 2f
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jal _mips_cps_putc
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PTR_ADDIU s6, s6, 1
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b 1b
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2: jr s7
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END(_mips_cps_puts)
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/**
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* _mips_cps_putx4 - write a 4b hex value to the UART
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* @a0: the 4b value to write to the UART
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* @t9: UART base address
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*
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* Write a single hexadecimal character to the UART.
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*/
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NESTED(_mips_cps_putx4, 0, ra)
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andi a0, a0, 0xf
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li t0, '0'
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blt a0, 10, 1f
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li t0, 'a'
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addiu a0, a0, -10
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1: addu a0, a0, t0
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b _mips_cps_putc
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END(_mips_cps_putx4)
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/**
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* _mips_cps_putx8 - write an 8b hex value to the UART
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* @a0: the 8b value to write to the UART
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* @t9: UART base address
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*
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* Write an 8 bit value (ie. 2 hexadecimal characters) to the UART.
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*/
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NESTED(_mips_cps_putx8, 0, ra)
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move s3, ra
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move s2, a0
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srl a0, a0, 4
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jal _mips_cps_putx4
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move a0, s2
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move ra, s3
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b _mips_cps_putx4
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END(_mips_cps_putx8)
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/**
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* _mips_cps_putx16 - write a 16b hex value to the UART
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* @a0: the 16b value to write to the UART
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* @t9: UART base address
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*
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* Write a 16 bit value (ie. 4 hexadecimal characters) to the UART.
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*/
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NESTED(_mips_cps_putx16, 0, ra)
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move s5, ra
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move s4, a0
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srl a0, a0, 8
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jal _mips_cps_putx8
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move a0, s4
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move ra, s5
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b _mips_cps_putx8
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END(_mips_cps_putx16)
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/**
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* _mips_cps_putx32 - write a 32b hex value to the UART
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* @a0: the 32b value to write to the UART
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* @t9: UART base address
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*
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* Write a 32 bit value (ie. 8 hexadecimal characters) to the UART.
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*/
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NESTED(_mips_cps_putx32, 0, ra)
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move s7, ra
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move s6, a0
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srl a0, a0, 16
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jal _mips_cps_putx16
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move a0, s6
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move ra, s7
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b _mips_cps_putx16
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END(_mips_cps_putx32)
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#ifdef CONFIG_64BIT
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/**
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* _mips_cps_putx64 - write a 64b hex value to the UART
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* @a0: the 64b value to write to the UART
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* @t9: UART base address
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*
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* Write a 64 bit value (ie. 16 hexadecimal characters) to the UART.
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*/
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NESTED(_mips_cps_putx64, 0, ra)
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move sp, ra
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move s8, a0
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dsrl32 a0, a0, 0
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jal _mips_cps_putx32
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move a0, s8
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move ra, sp
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b _mips_cps_putx32
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END(_mips_cps_putx64)
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#define _mips_cps_putxlong _mips_cps_putx64
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#else /* !CONFIG_64BIT */
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#define _mips_cps_putxlong _mips_cps_putx32
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#endif /* !CONFIG_64BIT */
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/**
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* mips_cps_bev_dump() - dump relevant exception state to UART
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* @a0: pointer to NULL-terminated ASCII string naming the exception
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*
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* Write information that may be useful in debugging an exception to the
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* UART configured by CONFIG_MIPS_CPS_NS16550_*. As this BEV exception
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* will only be run if something goes horribly wrong very early during
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* the bringup of a core and it is very likely to be unsafe to perform
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* memory accesses at that point (cache state indeterminate, EVA may not
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* be configured, coherence may be disabled) let alone have a stack,
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* this is all written in assembly using only registers & unmapped
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* uncached access to the UART registers.
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*/
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LEAF(mips_cps_bev_dump)
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move s0, ra
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move s1, a0
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li t9, CKSEG1ADDR(CONFIG_MIPS_CPS_NS16550_BASE)
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PTR_LA a0, str_newline
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jal _mips_cps_puts
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PTR_LA a0, str_bev
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jal _mips_cps_puts
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move a0, s1
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jal _mips_cps_puts
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PTR_LA a0, str_newline
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jal _mips_cps_puts
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PTR_LA a0, str_newline
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jal _mips_cps_puts
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#define DUMP_COP0_REG(reg, name, sz, _mfc0) \
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PTR_LA a0, 8f; \
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jal _mips_cps_puts; \
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_mfc0 a0, reg; \
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jal _mips_cps_putx##sz; \
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PTR_LA a0, str_newline; \
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jal _mips_cps_puts; \
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TEXT(name)
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DUMP_COP0_REG(CP0_CAUSE, "Cause: 0x", 32, mfc0)
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DUMP_COP0_REG(CP0_STATUS, "Status: 0x", 32, mfc0)
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DUMP_COP0_REG(CP0_EBASE, "EBase: 0x", long, MFC0)
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DUMP_COP0_REG(CP0_BADVADDR, "BadVAddr: 0x", long, MFC0)
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DUMP_COP0_REG(CP0_BADINSTR, "BadInstr: 0x", 32, mfc0)
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PTR_LA a0, str_newline
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jal _mips_cps_puts
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jr s0
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END(mips_cps_bev_dump)
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.pushsection .data
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str_bev: .asciiz "BEV Exception: "
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str_newline: .asciiz "\r\n"
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.popsection
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