1###############################################################################
2#
3# 16550 serial Rx interrupt handler for gdbstub 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/cpu-regs.h>
18#include <asm/thread_info.h>
19#include <asm/frame.inc>
20#include <asm/intctl-regs.h>
21#include <asm/irqflags.h>
22#include <unit/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#if 1
38	movbu	(GDBPORT_SERIAL_IIR),d2
39#endif
40
41	mov	(gdbstub_rx_inp),a3
42gdbstub_io_rx_more:
43	mov	a3,a2
44	add	2,a3
45	and	0x00000fff,a3
46	mov	(gdbstub_rx_outp),d3
47	cmp	a3,d3
48	beq	gdbstub_io_rx_overflow
49
50	movbu	(GDBPORT_SERIAL_LSR),d3
51	btst	UART_LSR_DR,d3
52	beq	gdbstub_io_rx_done
53	movbu	(GDBPORT_SERIAL_RX),d2
54	movbu	d3,(gdbstub_rx_buffer+1,a2)
55	movbu	d2,(gdbstub_rx_buffer,a2)
56	mov	a3,(gdbstub_rx_inp)
57	bra	gdbstub_io_rx_more
58
59gdbstub_io_rx_done:
60	mov	GxICR_DETECT,d2
61	movbu	d2,(XIRQxICR(GDBPORT_SERIAL_IRQ))	# ACK the interrupt
62	movhu	(XIRQxICR(GDBPORT_SERIAL_IRQ)),d2	# flush
63	movm	(sp),[d2,d3,a2,a3]
64	bset	0x01,(gdbstub_busy)
65	beq	gdbstub_io_rx_enter
66	rti
67
68gdbstub_io_rx_overflow:
69	bset	0x01,(gdbstub_rx_overflow)
70	bra	gdbstub_io_rx_done
71
72gdbstub_io_rx_enter:
73	LOCAL_CHANGE_INTR_MASK_LEVEL(NUM2EPSW_IM(CONFIG_GDBSTUB_IRQ_LEVEL+1))
74	add	-4,sp
75	SAVE_ALL
76
77	mov	0xffffffff,d0
78	mov	d0,(REG_ORIG_D0,fp)
79	mov	0x280,d1
80
81	mov	fp,d0
82	call	gdbstub_rx_irq[],0	# gdbstub_rx_irq(regs,excep)
83
84	LOCAL_CLI
85	bclr	0x01,(gdbstub_busy)
86
87	.globl gdbstub_return
88gdbstub_return:
89	RESTORE_ALL
90
91	.size	gdbstub_io_rx_handler,.-gdbstub_io_rx_handler
92