1###############################################################################
2#
3# MN10300 On-chip serial Rx interrupt handler for GDB stub I/O
4#
5# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
6# Written by David Howells (dhowells@redhat.com)
7#
8# This program is free software; you can redistribute it and/or
9# modify it under the terms of the GNU General Public Licence
10# as published by the Free Software Foundation; either version
11# 2 of the Licence, or (at your option) any later version.
12#
13###############################################################################
14#include <linux/sys.h>
15#include <linux/linkage.h>
16#include <asm/smp.h>
17#include <asm/thread_info.h>
18#include <asm/cpu-regs.h>
19#include <asm/frame.inc>
20#include <asm/intctl-regs.h>
21#include <unit/serial.h>
22#include "mn10300-serial.h"
23
24	.text
25
26###############################################################################
27#
28# GDB stub serial receive interrupt entry point
29# - intended to run at interrupt priority 0
30#
31###############################################################################
32	.globl	gdbstub_io_rx_handler
33	.type	gdbstub_io_rx_handler,@function
34gdbstub_io_rx_handler:
35	movm	[d2,d3,a2,a3],(sp)
36
37	mov	(gdbstub_rx_inp),a3
38gdbstub_io_rx_more:
39	mov	a3,a2
40	add	2,a3
41	and	PAGE_SIZE_asm-1,a3
42	mov	(gdbstub_rx_outp),d3
43	cmp	a3,d3
44	beq	gdbstub_io_rx_overflow
45
46	movbu	(SCgSTR),d3
47	btst	SC01STR_RBF,d3
48	beq	gdbstub_io_rx_done
49	movbu	(SCgRXB),d2
50	movbu	d3,(gdbstub_rx_buffer+1,a2)
51	movbu	d2,(gdbstub_rx_buffer,a2)
52	mov	a3,(gdbstub_rx_inp)
53	bra	gdbstub_io_rx_more
54
55gdbstub_io_rx_done:
56	mov	GxICR_DETECT,d2
57	movbu	d2,(GxICR(SCgRXIRQ))	# ACK the interrupt
58	movhu	(GxICR(SCgRXIRQ)),d2	# flush
59
60	movm	(sp),[d2,d3,a2,a3]
61	bset	0x01,(gdbstub_busy)
62	beq	gdbstub_io_rx_enter
63	rti
64
65gdbstub_io_rx_overflow:
66	bset	0x01,(gdbstub_rx_overflow)
67	bra	gdbstub_io_rx_done
68
69###############################################################################
70#
71# debugging interrupt - enter the GDB stub proper
72#
73###############################################################################
74gdbstub_io_rx_enter:
75	or	EPSW_IE|EPSW_IM_1,epsw
76	add	-4,sp
77	SAVE_ALL
78
79	mov	0xffffffff,d0
80	mov	d0,(REG_ORIG_D0,fp)
81	mov	0x280,d1
82
83	mov	fp,d0
84	call	gdbstub_rx_irq[],0	# gdbstub_io_rx_irq(regs,excep)
85
86	and	~EPSW_IE,epsw
87	bclr	0x01,(gdbstub_busy)
88
89	.globl gdbstub_return
90gdbstub_return:
91	RESTORE_ALL
92
93	.size	gdbstub_io_rx_handler,.-gdbstub_io_rx_handler
94