1/* gdb-io.c: FR403 GDB stub I/O
2 *
3 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/string.h>
13#include <linux/kernel.h>
14#include <linux/signal.h>
15#include <linux/sched.h>
16#include <linux/mm.h>
17#include <linux/console.h>
18#include <linux/init.h>
19#include <linux/serial_reg.h>
20
21#include <asm/pgtable.h>
22#include <asm/system.h>
23#include <asm/irc-regs.h>
24#include <asm/timer-regs.h>
25#include <asm/gdb-stub.h>
26#include "gdb-io.h"
27
28#ifdef CONFIG_GDBSTUB_UART0
29#define __UART(X) (*(volatile uint8_t *)(UART0_BASE + (UART_##X)))
30#define __UART_IRR_NMI 0xff0f0000
31#else /* CONFIG_GDBSTUB_UART1 */
32#define __UART(X) (*(volatile uint8_t *)(UART1_BASE + (UART_##X)))
33#define __UART_IRR_NMI 0xfff00000
34#endif
35
36#define LSR_WAIT_FOR(STATE)			\
37do {						\
38	gdbstub_do_rx();			\
39} while (!(__UART(LSR) & UART_LSR_##STATE))
40
41#define FLOWCTL_QUERY(LINE)	({ __UART(MSR) & UART_MSR_##LINE; })
42#define FLOWCTL_CLEAR(LINE)	do { __UART(MCR) &= ~UART_MCR_##LINE; mb(); } while (0)
43#define FLOWCTL_SET(LINE)	do { __UART(MCR) |= UART_MCR_##LINE;  mb(); } while (0)
44
45#define FLOWCTL_WAIT_FOR(LINE)			\
46do {						\
47	gdbstub_do_rx();			\
48} while(!FLOWCTL_QUERY(LINE))
49
50/*****************************************************************************/
51/*
52 * initialise the GDB stub
53 * - called with PSR.ET==0, so can't incur external interrupts
54 */
55void gdbstub_io_init(void)
56{
57	/* set up the serial port */
58	__UART(LCR) = UART_LCR_WLEN8; /* 1N8 */
59	__UART(FCR) =
60		UART_FCR_ENABLE_FIFO |
61		UART_FCR_CLEAR_RCVR |
62		UART_FCR_CLEAR_XMIT |
63		UART_FCR_TRIGGER_1;
64
65	FLOWCTL_CLEAR(DTR);
66	FLOWCTL_SET(RTS);
67
68//	gdbstub_set_baud(115200);
69
70	/* we want to get serial receive interrupts */
71	__UART(IER) = UART_IER_RDI | UART_IER_RLSI;
72	mb();
73
74	__set_IRR(6, __UART_IRR_NMI);	/* map ERRs and UARTx to NMI */
75
76} /* end gdbstub_io_init() */
77
78/*****************************************************************************/
79/*
80 * set up the GDB stub serial port baud rate timers
81 */
82void gdbstub_set_baud(unsigned baud)
83{
84	unsigned value, high, low;
85	u8 lcr;
86
87	/* work out the divisor to give us the nearest higher baud rate */
88	value = __serial_clock_speed_HZ / 16 / baud;
89
90	/* determine the baud rate range */
91	high = __serial_clock_speed_HZ / 16 / value;
92	low = __serial_clock_speed_HZ / 16 / (value + 1);
93
94	/* pick the nearest bound */
95	if (low + (high - low) / 2 > baud)
96		value++;
97
98	lcr = __UART(LCR);
99	__UART(LCR) |= UART_LCR_DLAB;
100	mb();
101	__UART(DLL) = value & 0xff;
102	__UART(DLM) = (value >> 8) & 0xff;
103	mb();
104	__UART(LCR) = lcr;
105	mb();
106
107} /* end gdbstub_set_baud() */
108
109/*****************************************************************************/
110/*
111 * receive characters into the receive FIFO
112 */
113void gdbstub_do_rx(void)
114{
115	unsigned ix, nix;
116
117	ix = gdbstub_rx_inp;
118
119	while (__UART(LSR) & UART_LSR_DR) {
120		nix = (ix + 2) & 0xfff;
121		if (nix == gdbstub_rx_outp)
122			break;
123
124		gdbstub_rx_buffer[ix++] = __UART(LSR);
125		gdbstub_rx_buffer[ix++] = __UART(RX);
126		ix = nix;
127	}
128
129	gdbstub_rx_inp = ix;
130
131	__clr_RC(15);
132	__clr_IRL();
133
134} /* end gdbstub_do_rx() */
135
136/*****************************************************************************/
137/*
138 * wait for a character to come from the debugger
139 */
140int gdbstub_rx_char(unsigned char *_ch, int nonblock)
141{
142	unsigned ix;
143	u8 ch, st;
144
145	*_ch = 0xff;
146
147	if (gdbstub_rx_unget) {
148		*_ch = gdbstub_rx_unget;
149		gdbstub_rx_unget = 0;
150		return 0;
151	}
152
153 try_again:
154	gdbstub_do_rx();
155
156	/* pull chars out of the buffer */
157	ix = gdbstub_rx_outp;
158	if (ix == gdbstub_rx_inp) {
159		if (nonblock)
160			return -EAGAIN;
161		//watchdog_alert_counter = 0;
162		goto try_again;
163	}
164
165	st = gdbstub_rx_buffer[ix++];
166	ch = gdbstub_rx_buffer[ix++];
167	gdbstub_rx_outp = ix & 0x00000fff;
168
169	if (st & UART_LSR_BI) {
170		gdbstub_proto("### GDB Rx Break Detected ###\n");
171		return -EINTR;
172	}
173	else if (st & (UART_LSR_FE|UART_LSR_OE|UART_LSR_PE)) {
174		gdbstub_proto("### GDB Rx Error (st=%02x) ###\n",st);
175		return -EIO;
176	}
177	else {
178		gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n",ch,st);
179		*_ch = ch & 0x7f;
180		return 0;
181	}
182
183} /* end gdbstub_rx_char() */
184
185/*****************************************************************************/
186/*
187 * send a character to the debugger
188 */
189void gdbstub_tx_char(unsigned char ch)
190{
191	FLOWCTL_SET(DTR);
192	LSR_WAIT_FOR(THRE);
193//	FLOWCTL_WAIT_FOR(CTS);
194
195	if (ch == 0x0a) {
196		__UART(TX) = 0x0d;
197		mb();
198		LSR_WAIT_FOR(THRE);
199//		FLOWCTL_WAIT_FOR(CTS);
200	}
201	__UART(TX) = ch;
202	mb();
203
204	FLOWCTL_CLEAR(DTR);
205} /* end gdbstub_tx_char() */
206
207/*****************************************************************************/
208/*
209 * send a character to the debugger
210 */
211void gdbstub_tx_flush(void)
212{
213	LSR_WAIT_FOR(TEMT);
214	LSR_WAIT_FOR(THRE);
215	FLOWCTL_CLEAR(DTR);
216} /* end gdbstub_tx_flush() */
217