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_io("### GDB Rx Error (st=%02x) ###\n",st);
175		return -EIO;
176	}
177	else {
178		gdbstub_io("### 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() */