1 /* 16550 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/nmi.h> 19 20 #include <asm/pgtable.h> 21 #include <asm/gdb-stub.h> 22 #include <asm/exceptions.h> 23 #include <asm/serial-regs.h> 24 #include <unit/serial.h> 25 #include <asm/smp.h> 26 27 /* 28 * initialise the GDB stub 29 */ gdbstub_io_init(void)30void gdbstub_io_init(void) 31 { 32 u16 tmp; 33 34 /* set up the serial port */ 35 GDBPORT_SERIAL_LCR = UART_LCR_WLEN8; /* 1N8 */ 36 GDBPORT_SERIAL_FCR = (UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | 37 UART_FCR_CLEAR_XMIT); 38 39 FLOWCTL_CLEAR(DTR); 40 FLOWCTL_SET(RTS); 41 42 gdbstub_io_set_baud(115200); 43 44 /* we want to get serial receive interrupts */ 45 XIRQxICR(GDBPORT_SERIAL_IRQ) = 0; 46 tmp = XIRQxICR(GDBPORT_SERIAL_IRQ); 47 48 #if CONFIG_GDBSTUB_IRQ_LEVEL == 0 49 IVAR0 = EXCEP_IRQ_LEVEL0; 50 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 1 51 IVAR1 = EXCEP_IRQ_LEVEL1; 52 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 2 53 IVAR2 = EXCEP_IRQ_LEVEL2; 54 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 3 55 IVAR3 = EXCEP_IRQ_LEVEL3; 56 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 4 57 IVAR4 = EXCEP_IRQ_LEVEL4; 58 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 5 59 IVAR5 = EXCEP_IRQ_LEVEL5; 60 #else 61 #error "Unknown irq level for gdbstub." 62 #endif 63 64 set_intr_stub(NUM2EXCEP_IRQ_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL), 65 gdbstub_io_rx_handler); 66 67 XIRQxICR(GDBPORT_SERIAL_IRQ) &= ~GxICR_REQUEST; 68 XIRQxICR(GDBPORT_SERIAL_IRQ) = 69 GxICR_ENABLE | NUM2GxICR_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL); 70 tmp = XIRQxICR(GDBPORT_SERIAL_IRQ); 71 72 GDBPORT_SERIAL_IER = UART_IER_RDI | UART_IER_RLSI; 73 74 /* permit level 0 IRQs to take place */ 75 arch_local_change_intr_mask_level( 76 NUM2EPSW_IM(CONFIG_GDBSTUB_IRQ_LEVEL + 1)); 77 } 78 79 /* 80 * set up the GDB stub serial port baud rate timers 81 */ gdbstub_io_set_baud(unsigned baud)82void gdbstub_io_set_baud(unsigned baud) 83 { 84 unsigned value; 85 u8 lcr; 86 87 value = 18432000 / 16 / baud; 88 89 lcr = GDBPORT_SERIAL_LCR; 90 GDBPORT_SERIAL_LCR |= UART_LCR_DLAB; 91 GDBPORT_SERIAL_DLL = value & 0xff; 92 GDBPORT_SERIAL_DLM = (value >> 8) & 0xff; 93 GDBPORT_SERIAL_LCR = lcr; 94 } 95 96 /* 97 * wait for a character to come from the debugger 98 */ gdbstub_io_rx_char(unsigned char * _ch,int nonblock)99int gdbstub_io_rx_char(unsigned char *_ch, int nonblock) 100 { 101 unsigned ix; 102 u8 ch, st; 103 #if defined(CONFIG_MN10300_WD_TIMER) 104 int cpu; 105 #endif 106 107 *_ch = 0xff; 108 109 if (gdbstub_rx_unget) { 110 *_ch = gdbstub_rx_unget; 111 gdbstub_rx_unget = 0; 112 return 0; 113 } 114 115 try_again: 116 /* pull chars out of the buffer */ 117 ix = gdbstub_rx_outp; 118 barrier(); 119 if (ix == gdbstub_rx_inp) { 120 if (nonblock) 121 return -EAGAIN; 122 #ifdef CONFIG_MN10300_WD_TIMER 123 for (cpu = 0; cpu < NR_CPUS; cpu++) 124 watchdog_alert_counter[cpu] = 0; 125 #endif 126 goto try_again; 127 } 128 129 ch = gdbstub_rx_buffer[ix++]; 130 st = gdbstub_rx_buffer[ix++]; 131 barrier(); 132 gdbstub_rx_outp = ix & 0x00000fff; 133 134 if (st & UART_LSR_BI) { 135 gdbstub_proto("### GDB Rx Break Detected ###\n"); 136 return -EINTR; 137 } else if (st & (UART_LSR_FE | UART_LSR_OE | UART_LSR_PE)) { 138 gdbstub_proto("### GDB Rx Error (st=%02x) ###\n", st); 139 return -EIO; 140 } else { 141 gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n", ch, st); 142 *_ch = ch & 0x7f; 143 return 0; 144 } 145 } 146 147 /* 148 * send a character to the debugger 149 */ gdbstub_io_tx_char(unsigned char ch)150void gdbstub_io_tx_char(unsigned char ch) 151 { 152 FLOWCTL_SET(DTR); 153 LSR_WAIT_FOR(THRE); 154 /* FLOWCTL_WAIT_FOR(CTS); */ 155 156 if (ch == 0x0a) { 157 GDBPORT_SERIAL_TX = 0x0d; 158 LSR_WAIT_FOR(THRE); 159 /* FLOWCTL_WAIT_FOR(CTS); */ 160 } 161 GDBPORT_SERIAL_TX = ch; 162 163 FLOWCTL_CLEAR(DTR); 164 } 165 166 /* 167 * send a character to the debugger 168 */ gdbstub_io_tx_flush(void)169void gdbstub_io_tx_flush(void) 170 { 171 LSR_WAIT_FOR(TEMT); 172 LSR_WAIT_FOR(THRE); 173 FLOWCTL_CLEAR(DTR); 174 } 175