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/system.h> 22 #include <asm/gdb-stub.h> 23 #include <asm/exceptions.h> 24 #include <asm/serial-regs.h> 25 #include <unit/serial.h> 26 #include <asm/smp.h> 27 28 /* 29 * initialise the GDB stub 30 */ gdbstub_io_init(void)31void gdbstub_io_init(void) 32 { 33 u16 tmp; 34 35 /* set up the serial port */ 36 GDBPORT_SERIAL_LCR = UART_LCR_WLEN8; /* 1N8 */ 37 GDBPORT_SERIAL_FCR = (UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | 38 UART_FCR_CLEAR_XMIT); 39 40 FLOWCTL_CLEAR(DTR); 41 FLOWCTL_SET(RTS); 42 43 gdbstub_io_set_baud(115200); 44 45 /* we want to get serial receive interrupts */ 46 XIRQxICR(GDBPORT_SERIAL_IRQ) = 0; 47 tmp = XIRQxICR(GDBPORT_SERIAL_IRQ); 48 49 #if CONFIG_GDBSTUB_IRQ_LEVEL == 0 50 IVAR0 = EXCEP_IRQ_LEVEL0; 51 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 1 52 IVAR1 = EXCEP_IRQ_LEVEL1; 53 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 2 54 IVAR2 = EXCEP_IRQ_LEVEL2; 55 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 3 56 IVAR3 = EXCEP_IRQ_LEVEL3; 57 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 4 58 IVAR4 = EXCEP_IRQ_LEVEL4; 59 #elif CONFIG_GDBSTUB_IRQ_LEVEL == 5 60 IVAR5 = EXCEP_IRQ_LEVEL5; 61 #else 62 #error "Unknown irq level for gdbstub." 63 #endif 64 65 set_intr_stub(NUM2EXCEP_IRQ_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL), 66 gdbstub_io_rx_handler); 67 68 XIRQxICR(GDBPORT_SERIAL_IRQ) &= ~GxICR_REQUEST; 69 XIRQxICR(GDBPORT_SERIAL_IRQ) = 70 GxICR_ENABLE | NUM2GxICR_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL); 71 tmp = XIRQxICR(GDBPORT_SERIAL_IRQ); 72 73 GDBPORT_SERIAL_IER = UART_IER_RDI | UART_IER_RLSI; 74 75 /* permit level 0 IRQs to take place */ 76 arch_local_change_intr_mask_level( 77 NUM2EPSW_IM(CONFIG_GDBSTUB_IRQ_LEVEL + 1)); 78 } 79 80 /* 81 * set up the GDB stub serial port baud rate timers 82 */ gdbstub_io_set_baud(unsigned baud)83void gdbstub_io_set_baud(unsigned baud) 84 { 85 unsigned value; 86 u8 lcr; 87 88 value = 18432000 / 16 / baud; 89 90 lcr = GDBPORT_SERIAL_LCR; 91 GDBPORT_SERIAL_LCR |= UART_LCR_DLAB; 92 GDBPORT_SERIAL_DLL = value & 0xff; 93 GDBPORT_SERIAL_DLM = (value >> 8) & 0xff; 94 GDBPORT_SERIAL_LCR = lcr; 95 } 96 97 /* 98 * wait for a character to come from the debugger 99 */ gdbstub_io_rx_char(unsigned char * _ch,int nonblock)100int gdbstub_io_rx_char(unsigned char *_ch, int nonblock) 101 { 102 unsigned ix; 103 u8 ch, st; 104 #if defined(CONFIG_MN10300_WD_TIMER) 105 int cpu; 106 #endif 107 108 *_ch = 0xff; 109 110 if (gdbstub_rx_unget) { 111 *_ch = gdbstub_rx_unget; 112 gdbstub_rx_unget = 0; 113 return 0; 114 } 115 116 try_again: 117 /* pull chars out of the buffer */ 118 ix = gdbstub_rx_outp; 119 barrier(); 120 if (ix == gdbstub_rx_inp) { 121 if (nonblock) 122 return -EAGAIN; 123 #ifdef CONFIG_MN10300_WD_TIMER 124 for (cpu = 0; cpu < NR_CPUS; cpu++) 125 watchdog_alert_counter[cpu] = 0; 126 #endif 127 goto try_again; 128 } 129 130 ch = gdbstub_rx_buffer[ix++]; 131 st = gdbstub_rx_buffer[ix++]; 132 barrier(); 133 gdbstub_rx_outp = ix & 0x00000fff; 134 135 if (st & UART_LSR_BI) { 136 gdbstub_proto("### GDB Rx Break Detected ###\n"); 137 return -EINTR; 138 } else if (st & (UART_LSR_FE | UART_LSR_OE | UART_LSR_PE)) { 139 gdbstub_proto("### GDB Rx Error (st=%02x) ###\n", st); 140 return -EIO; 141 } else { 142 gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n", ch, st); 143 *_ch = ch & 0x7f; 144 return 0; 145 } 146 } 147 148 /* 149 * send a character to the debugger 150 */ gdbstub_io_tx_char(unsigned char ch)151void gdbstub_io_tx_char(unsigned char ch) 152 { 153 FLOWCTL_SET(DTR); 154 LSR_WAIT_FOR(THRE); 155 /* FLOWCTL_WAIT_FOR(CTS); */ 156 157 if (ch == 0x0a) { 158 GDBPORT_SERIAL_TX = 0x0d; 159 LSR_WAIT_FOR(THRE); 160 /* FLOWCTL_WAIT_FOR(CTS); */ 161 } 162 GDBPORT_SERIAL_TX = ch; 163 164 FLOWCTL_CLEAR(DTR); 165 } 166 167 /* 168 * send a character to the debugger 169 */ gdbstub_io_tx_flush(void)170void gdbstub_io_tx_flush(void) 171 { 172 LSR_WAIT_FOR(TEMT); 173 LSR_WAIT_FOR(THRE); 174 FLOWCTL_CLEAR(DTR); 175 } 176