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