1 /* MN10300 On-chip serial driver for gdbstub I/O
2 *
3 * Copyright (C) 2007 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 Licence
8 * as published by the Free Software Foundation; either version
9 * 2 of the Licence, or (at your option) any later version.
10 */
11 #include <linux/string.h>
12 #include <linux/kernel.h>
13 #include <linux/signal.h>
14 #include <linux/sched.h>
15 #include <linux/mm.h>
16 #include <linux/console.h>
17 #include <linux/init.h>
18 #include <linux/tty.h>
19 #include <asm/pgtable.h>
20 #include <asm/system.h>
21 #include <asm/gdb-stub.h>
22 #include <asm/exceptions.h>
23 #include <unit/clock.h>
24 #include "mn10300-serial.h"
25
26 #if defined(CONFIG_GDBSTUB_ON_TTYSM0)
27 struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif0;
28 #elif defined(CONFIG_GDBSTUB_ON_TTYSM1)
29 struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif1;
30 #else
31 struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif2;
32 #endif
33
34
35 /*
36 * initialise the GDB stub I/O routines
37 */
gdbstub_io_init(void)38 void __init gdbstub_io_init(void)
39 {
40 uint16_t scxctr;
41 int tmp;
42
43 switch (gdbstub_port->clock_src) {
44 case MNSCx_CLOCK_SRC_IOCLK:
45 gdbstub_port->ioclk = MN10300_IOCLK;
46 break;
47
48 #ifdef MN10300_IOBCLK
49 case MNSCx_CLOCK_SRC_IOBCLK:
50 gdbstub_port->ioclk = MN10300_IOBCLK;
51 break;
52 #endif
53 default:
54 BUG();
55 }
56
57 /* set up the serial port */
58 gdbstub_io_set_baud(115200);
59
60 /* we want to get serial receive interrupts */
61 set_intr_level(gdbstub_port->rx_irq,
62 NUM2GxICR_LEVEL(CONFIG_DEBUGGER_IRQ_LEVEL));
63 set_intr_level(gdbstub_port->tx_irq,
64 NUM2GxICR_LEVEL(CONFIG_DEBUGGER_IRQ_LEVEL));
65 set_intr_stub(NUM2EXCEP_IRQ_LEVEL(CONFIG_DEBUGGER_IRQ_LEVEL),
66 gdbstub_io_rx_handler);
67
68 *gdbstub_port->rx_icr |= GxICR_ENABLE;
69 tmp = *gdbstub_port->rx_icr;
70
71 /* enable the device */
72 scxctr = SC01CTR_CLN_8BIT; /* 1N8 */
73 switch (gdbstub_port->div_timer) {
74 case MNSCx_DIV_TIMER_16BIT:
75 scxctr |= SC0CTR_CK_TM8UFLOW_8; /* == SC1CTR_CK_TM9UFLOW_8
76 == SC2CTR_CK_TM10UFLOW_8 */
77 break;
78
79 case MNSCx_DIV_TIMER_8BIT:
80 scxctr |= SC0CTR_CK_TM2UFLOW_8;
81 break;
82 }
83
84 scxctr |= SC01CTR_TXE | SC01CTR_RXE;
85
86 *gdbstub_port->_control = scxctr;
87 tmp = *gdbstub_port->_control;
88
89 /* permit level 0 IRQs only */
90 arch_local_change_intr_mask_level(
91 NUM2EPSW_IM(CONFIG_DEBUGGER_IRQ_LEVEL + 1));
92 }
93
94 /*
95 * set up the GDB stub serial port baud rate timers
96 */
gdbstub_io_set_baud(unsigned baud)97 void gdbstub_io_set_baud(unsigned baud)
98 {
99 const unsigned bits = 10; /* 1 [start] + 8 [data] + 0 [parity] +
100 * 1 [stop] */
101 unsigned long ioclk = gdbstub_port->ioclk;
102 unsigned xdiv, tmp;
103 uint16_t tmxbr;
104 uint8_t tmxmd;
105
106 if (!baud) {
107 baud = 9600;
108 } else if (baud == 134) {
109 baud = 269; /* 134 is really 134.5 */
110 xdiv = 2;
111 }
112
113 try_alternative:
114 xdiv = 1;
115
116 switch (gdbstub_port->div_timer) {
117 case MNSCx_DIV_TIMER_16BIT:
118 tmxmd = TM8MD_SRC_IOCLK;
119 tmxbr = tmp = (ioclk / (baud * xdiv) + 4) / 8 - 1;
120 if (tmp > 0 && tmp <= 65535)
121 goto timer_okay;
122
123 tmxmd = TM8MD_SRC_IOCLK_8;
124 tmxbr = tmp = (ioclk / (baud * 8 * xdiv) + 4) / 8 - 1;
125 if (tmp > 0 && tmp <= 65535)
126 goto timer_okay;
127
128 tmxmd = TM8MD_SRC_IOCLK_32;
129 tmxbr = tmp = (ioclk / (baud * 32 * xdiv) + 4) / 8 - 1;
130 if (tmp > 0 && tmp <= 65535)
131 goto timer_okay;
132
133 break;
134
135 case MNSCx_DIV_TIMER_8BIT:
136 tmxmd = TM2MD_SRC_IOCLK;
137 tmxbr = tmp = (ioclk / (baud * xdiv) + 4) / 8 - 1;
138 if (tmp > 0 && tmp <= 255)
139 goto timer_okay;
140
141 tmxmd = TM2MD_SRC_IOCLK_8;
142 tmxbr = tmp = (ioclk / (baud * 8 * xdiv) + 4) / 8 - 1;
143 if (tmp > 0 && tmp <= 255)
144 goto timer_okay;
145
146 tmxmd = TM2MD_SRC_IOCLK_32;
147 tmxbr = tmp = (ioclk / (baud * 32 * xdiv) + 4) / 8 - 1;
148 if (tmp > 0 && tmp <= 255)
149 goto timer_okay;
150 break;
151 }
152
153 /* as a last resort, if the quotient is zero, default to 9600 bps */
154 baud = 9600;
155 goto try_alternative;
156
157 timer_okay:
158 gdbstub_port->uart.timeout = (2 * bits * HZ) / baud;
159 gdbstub_port->uart.timeout += HZ / 50;
160
161 /* set the timer to produce the required baud rate */
162 switch (gdbstub_port->div_timer) {
163 case MNSCx_DIV_TIMER_16BIT:
164 *gdbstub_port->_tmxmd = 0;
165 *gdbstub_port->_tmxbr = tmxbr;
166 *gdbstub_port->_tmxmd = TM8MD_INIT_COUNTER;
167 *gdbstub_port->_tmxmd = tmxmd | TM8MD_COUNT_ENABLE;
168 break;
169
170 case MNSCx_DIV_TIMER_8BIT:
171 *gdbstub_port->_tmxmd = 0;
172 *(volatile u8 *) gdbstub_port->_tmxbr = (u8)tmxbr;
173 *gdbstub_port->_tmxmd = TM2MD_INIT_COUNTER;
174 *gdbstub_port->_tmxmd = tmxmd | TM2MD_COUNT_ENABLE;
175 break;
176 }
177 }
178
179 /*
180 * wait for a character to come from the debugger
181 */
gdbstub_io_rx_char(unsigned char * _ch,int nonblock)182 int gdbstub_io_rx_char(unsigned char *_ch, int nonblock)
183 {
184 unsigned ix;
185 u8 ch, st;
186 #if defined(CONFIG_MN10300_WD_TIMER)
187 int cpu;
188 #endif
189
190 *_ch = 0xff;
191
192 if (gdbstub_rx_unget) {
193 *_ch = gdbstub_rx_unget;
194 gdbstub_rx_unget = 0;
195 return 0;
196 }
197
198 try_again:
199 /* pull chars out of the buffer */
200 ix = gdbstub_rx_outp;
201 barrier();
202 if (ix == gdbstub_rx_inp) {
203 if (nonblock)
204 return -EAGAIN;
205 #ifdef CONFIG_MN10300_WD_TIMER
206 for (cpu = 0; cpu < NR_CPUS; cpu++)
207 watchdog_alert_counter[cpu] = 0;
208 #endif
209 goto try_again;
210 }
211
212 ch = gdbstub_rx_buffer[ix++];
213 st = gdbstub_rx_buffer[ix++];
214 barrier();
215 gdbstub_rx_outp = ix & (PAGE_SIZE - 1);
216
217 st &= SC01STR_RXF | SC01STR_RBF | SC01STR_FEF | SC01STR_PEF |
218 SC01STR_OEF;
219
220 /* deal with what we've got
221 * - note that the UART doesn't do BREAK-detection for us
222 */
223 if (st & SC01STR_FEF && ch == 0) {
224 switch (gdbstub_port->rx_brk) {
225 case 0: gdbstub_port->rx_brk = 1; goto try_again;
226 case 1: gdbstub_port->rx_brk = 2; goto try_again;
227 case 2:
228 gdbstub_port->rx_brk = 3;
229 gdbstub_proto("### GDB MNSERIAL Rx Break Detected"
230 " ###\n");
231 return -EINTR;
232 default:
233 goto try_again;
234 }
235 } else if (st & SC01STR_FEF) {
236 if (gdbstub_port->rx_brk)
237 goto try_again;
238
239 gdbstub_proto("### GDB MNSERIAL Framing Error ###\n");
240 return -EIO;
241 } else if (st & SC01STR_OEF) {
242 if (gdbstub_port->rx_brk)
243 goto try_again;
244
245 gdbstub_proto("### GDB MNSERIAL Overrun Error ###\n");
246 return -EIO;
247 } else if (st & SC01STR_PEF) {
248 if (gdbstub_port->rx_brk)
249 goto try_again;
250
251 gdbstub_proto("### GDB MNSERIAL Parity Error ###\n");
252 return -EIO;
253 } else {
254 /* look for the tail-end char on a break run */
255 if (gdbstub_port->rx_brk == 3) {
256 switch (ch) {
257 case 0xFF:
258 case 0xFE:
259 case 0xFC:
260 case 0xF8:
261 case 0xF0:
262 case 0xE0:
263 case 0xC0:
264 case 0x80:
265 case 0x00:
266 gdbstub_port->rx_brk = 0;
267 goto try_again;
268 default:
269 break;
270 }
271 }
272
273 gdbstub_port->rx_brk = 0;
274 gdbstub_io("### GDB Rx %02x (st=%02x) ###\n", ch, st);
275 *_ch = ch & 0x7f;
276 return 0;
277 }
278 }
279
280 /*
281 * send a character to the debugger
282 */
gdbstub_io_tx_char(unsigned char ch)283 void gdbstub_io_tx_char(unsigned char ch)
284 {
285 while (*gdbstub_port->_status & SC01STR_TBF)
286 continue;
287
288 if (ch == 0x0a) {
289 *(u8 *) gdbstub_port->_txb = 0x0d;
290 while (*gdbstub_port->_status & SC01STR_TBF)
291 continue;
292 }
293
294 *(u8 *) gdbstub_port->_txb = ch;
295 }
296
297 /*
298 * flush the transmission buffers
299 */
gdbstub_io_tx_flush(void)300 void gdbstub_io_tx_flush(void)
301 {
302 while (*gdbstub_port->_status & (SC01STR_TBF | SC01STR_TXF))
303 continue;
304 }
305