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) \
37 do { \
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) \
46 do { \
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 */
gdbstub_io_init(void)55 void 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 */
gdbstub_set_baud(unsigned baud)82 void 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 */
gdbstub_do_rx(void)113 void 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 */
gdbstub_rx_char(unsigned char * _ch,int nonblock)140 int 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 */
gdbstub_tx_char(unsigned char ch)189 void 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 */
gdbstub_tx_flush(void)211 void 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