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