| /* MN10300 On-chip serial driver for gdbstub I/O | 
 |  * | 
 |  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | 
 |  * Written by David Howells (dhowells@redhat.com) | 
 |  * | 
 |  * This program is free software; you can redistribute it and/or | 
 |  * modify it under the terms of the GNU General Public Licence | 
 |  * as published by the Free Software Foundation; either version | 
 |  * 2 of the Licence, or (at your option) any later version. | 
 |  */ | 
 | #include <linux/string.h> | 
 | #include <linux/kernel.h> | 
 | #include <linux/signal.h> | 
 | #include <linux/sched.h> | 
 | #include <linux/mm.h> | 
 | #include <linux/console.h> | 
 | #include <linux/init.h> | 
 | #include <linux/tty.h> | 
 | #include <asm/pgtable.h> | 
 | #include <asm/system.h> | 
 | #include <asm/gdb-stub.h> | 
 | #include <asm/exceptions.h> | 
 | #include <unit/clock.h> | 
 | #include "mn10300-serial.h" | 
 |  | 
 | #if defined(CONFIG_GDBSTUB_ON_TTYSM0) | 
 | struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif0; | 
 | #elif defined(CONFIG_GDBSTUB_ON_TTYSM1) | 
 | struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif1; | 
 | #else | 
 | struct mn10300_serial_port *const gdbstub_port = &mn10300_serial_port_sif2; | 
 | #endif | 
 |  | 
 |  | 
 | /* | 
 |  * initialise the GDB stub I/O routines | 
 |  */ | 
 | void __init gdbstub_io_init(void) | 
 | { | 
 | 	uint16_t scxctr; | 
 | 	int tmp; | 
 |  | 
 | 	switch (gdbstub_port->clock_src) { | 
 | 	case MNSCx_CLOCK_SRC_IOCLK: | 
 | 		gdbstub_port->ioclk = MN10300_IOCLK; | 
 | 		break; | 
 |  | 
 | #ifdef MN10300_IOBCLK | 
 | 	case MNSCx_CLOCK_SRC_IOBCLK: | 
 | 		gdbstub_port->ioclk = MN10300_IOBCLK; | 
 | 		break; | 
 | #endif | 
 | 	default: | 
 | 		BUG(); | 
 | 	} | 
 |  | 
 | 	/* set up the serial port */ | 
 | 	gdbstub_io_set_baud(115200); | 
 |  | 
 | 	/* we want to get serial receive interrupts */ | 
 | 	set_intr_level(gdbstub_port->rx_irq, GxICR_LEVEL_0); | 
 | 	set_intr_level(gdbstub_port->tx_irq, GxICR_LEVEL_0); | 
 | 	set_intr_stub(EXCEP_IRQ_LEVEL0, gdbstub_io_rx_handler); | 
 |  | 
 | 	*gdbstub_port->rx_icr |= GxICR_ENABLE; | 
 | 	tmp = *gdbstub_port->rx_icr; | 
 |  | 
 | 	/* enable the device */ | 
 | 	scxctr = SC01CTR_CLN_8BIT;	/* 1N8 */ | 
 | 	switch (gdbstub_port->div_timer) { | 
 | 	case MNSCx_DIV_TIMER_16BIT: | 
 | 		scxctr |= SC0CTR_CK_TM8UFLOW_8; /* == SC1CTR_CK_TM9UFLOW_8 | 
 | 						   == SC2CTR_CK_TM10UFLOW_8 */ | 
 | 		break; | 
 |  | 
 | 	case MNSCx_DIV_TIMER_8BIT: | 
 | 		scxctr |= SC0CTR_CK_TM2UFLOW_8; | 
 | 		break; | 
 | 	} | 
 |  | 
 | 	scxctr |= SC01CTR_TXE | SC01CTR_RXE; | 
 |  | 
 | 	*gdbstub_port->_control = scxctr; | 
 | 	tmp = *gdbstub_port->_control; | 
 |  | 
 | 	/* permit level 0 IRQs only */ | 
 | 	asm volatile( | 
 | 		"	and %0,epsw	\n" | 
 | 		"	or %1,epsw	\n" | 
 | 		: | 
 | 		: "i"(~EPSW_IM), "i"(EPSW_IE|EPSW_IM_1) | 
 | 		); | 
 | } | 
 |  | 
 | /* | 
 |  * set up the GDB stub serial port baud rate timers | 
 |  */ | 
 | void gdbstub_io_set_baud(unsigned baud) | 
 | { | 
 | 	const unsigned bits = 10; /* 1 [start] + 8 [data] + 0 [parity] + | 
 | 				   * 1 [stop] */ | 
 | 	unsigned long ioclk = gdbstub_port->ioclk; | 
 | 	unsigned xdiv, tmp; | 
 | 	uint16_t tmxbr; | 
 | 	uint8_t tmxmd; | 
 |  | 
 | 	if (!baud) { | 
 | 		baud = 9600; | 
 | 	} else if (baud == 134) { | 
 | 		baud = 269;	/* 134 is really 134.5 */ | 
 | 		xdiv = 2; | 
 | 	} | 
 |  | 
 | try_alternative: | 
 | 	xdiv = 1; | 
 |  | 
 | 	switch (gdbstub_port->div_timer) { | 
 | 	case MNSCx_DIV_TIMER_16BIT: | 
 | 		tmxmd = TM8MD_SRC_IOCLK; | 
 | 		tmxbr = tmp = (ioclk / (baud * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 65535) | 
 | 			goto timer_okay; | 
 |  | 
 | 		tmxmd = TM8MD_SRC_IOCLK_8; | 
 | 		tmxbr = tmp = (ioclk / (baud * 8 * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 65535) | 
 | 			goto timer_okay; | 
 |  | 
 | 		tmxmd = TM8MD_SRC_IOCLK_32; | 
 | 		tmxbr = tmp = (ioclk / (baud * 32 * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 65535) | 
 | 			goto timer_okay; | 
 |  | 
 | 		break; | 
 |  | 
 | 	case MNSCx_DIV_TIMER_8BIT: | 
 | 		tmxmd = TM2MD_SRC_IOCLK; | 
 | 		tmxbr = tmp = (ioclk / (baud * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 255) | 
 | 			goto timer_okay; | 
 |  | 
 | 		tmxmd = TM2MD_SRC_IOCLK_8; | 
 | 		tmxbr = tmp = (ioclk / (baud * 8 * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 255) | 
 | 			goto timer_okay; | 
 |  | 
 | 		tmxmd = TM2MD_SRC_IOCLK_32; | 
 | 		tmxbr = tmp = (ioclk / (baud * 32 * xdiv) + 4) / 8 - 1; | 
 | 		if (tmp > 0 && tmp <= 255) | 
 | 			goto timer_okay; | 
 | 		break; | 
 | 	} | 
 |  | 
 | 	/* as a last resort, if the quotient is zero, default to 9600 bps */ | 
 | 	baud = 9600; | 
 | 	goto try_alternative; | 
 |  | 
 | timer_okay: | 
 | 	gdbstub_port->uart.timeout = (2 * bits * HZ) / baud; | 
 | 	gdbstub_port->uart.timeout += HZ / 50; | 
 |  | 
 | 	/* set the timer to produce the required baud rate */ | 
 | 	switch (gdbstub_port->div_timer) { | 
 | 	case MNSCx_DIV_TIMER_16BIT: | 
 | 		*gdbstub_port->_tmxmd = 0; | 
 | 		*gdbstub_port->_tmxbr = tmxbr; | 
 | 		*gdbstub_port->_tmxmd = TM8MD_INIT_COUNTER; | 
 | 		*gdbstub_port->_tmxmd = tmxmd | TM8MD_COUNT_ENABLE; | 
 | 		break; | 
 |  | 
 | 	case MNSCx_DIV_TIMER_8BIT: | 
 | 		*gdbstub_port->_tmxmd = 0; | 
 | 		*(volatile u8 *) gdbstub_port->_tmxbr = (u8)tmxbr; | 
 | 		*gdbstub_port->_tmxmd = TM2MD_INIT_COUNTER; | 
 | 		*gdbstub_port->_tmxmd = tmxmd | TM2MD_COUNT_ENABLE; | 
 | 		break; | 
 | 	} | 
 | } | 
 |  | 
 | /* | 
 |  * wait for a character to come from the debugger | 
 |  */ | 
 | int gdbstub_io_rx_char(unsigned char *_ch, int nonblock) | 
 | { | 
 | 	unsigned ix; | 
 | 	u8 ch, st; | 
 |  | 
 | 	*_ch = 0xff; | 
 |  | 
 | 	if (gdbstub_rx_unget) { | 
 | 		*_ch = gdbstub_rx_unget; | 
 | 		gdbstub_rx_unget = 0; | 
 | 		return 0; | 
 | 	} | 
 |  | 
 | try_again: | 
 | 	/* pull chars out of the buffer */ | 
 | 	ix = gdbstub_rx_outp; | 
 | 	barrier(); | 
 | 	if (ix == gdbstub_rx_inp) { | 
 | 		if (nonblock) | 
 | 			return -EAGAIN; | 
 | #ifdef CONFIG_MN10300_WD_TIMER | 
 | 		watchdog_alert_counter = 0; | 
 | #endif /* CONFIG_MN10300_WD_TIMER */ | 
 | 		goto try_again; | 
 | 	} | 
 |  | 
 | 	ch = gdbstub_rx_buffer[ix++]; | 
 | 	st = gdbstub_rx_buffer[ix++]; | 
 | 	barrier(); | 
 | 	gdbstub_rx_outp = ix & (PAGE_SIZE - 1); | 
 |  | 
 | 	st &= SC01STR_RXF | SC01STR_RBF | SC01STR_FEF | SC01STR_PEF | | 
 | 		SC01STR_OEF; | 
 |  | 
 | 	/* deal with what we've got | 
 | 	 * - note that the UART doesn't do BREAK-detection for us | 
 | 	 */ | 
 | 	if (st & SC01STR_FEF && ch == 0) { | 
 | 		switch (gdbstub_port->rx_brk) { | 
 | 		case 0:	gdbstub_port->rx_brk = 1;	goto try_again; | 
 | 		case 1:	gdbstub_port->rx_brk = 2;	goto try_again; | 
 | 		case 2: | 
 | 			gdbstub_port->rx_brk = 3; | 
 | 			gdbstub_proto("### GDB MNSERIAL Rx Break Detected" | 
 | 				      " ###\n"); | 
 | 			return -EINTR; | 
 | 		default: | 
 | 			goto try_again; | 
 | 		} | 
 | 	} else if (st & SC01STR_FEF) { | 
 | 		if (gdbstub_port->rx_brk) | 
 | 			goto try_again; | 
 |  | 
 | 		gdbstub_proto("### GDB MNSERIAL Framing Error ###\n"); | 
 | 		return -EIO; | 
 | 	} else if (st & SC01STR_OEF) { | 
 | 		if (gdbstub_port->rx_brk) | 
 | 			goto try_again; | 
 |  | 
 | 		gdbstub_proto("### GDB MNSERIAL Overrun Error ###\n"); | 
 | 		return -EIO; | 
 | 	} else if (st & SC01STR_PEF) { | 
 | 		if (gdbstub_port->rx_brk) | 
 | 			goto try_again; | 
 |  | 
 | 		gdbstub_proto("### GDB MNSERIAL Parity Error ###\n"); | 
 | 		return -EIO; | 
 | 	} else { | 
 | 		/* look for the tail-end char on a break run */ | 
 | 		if (gdbstub_port->rx_brk == 3) { | 
 | 			switch (ch) { | 
 | 			case 0xFF: | 
 | 			case 0xFE: | 
 | 			case 0xFC: | 
 | 			case 0xF8: | 
 | 			case 0xF0: | 
 | 			case 0xE0: | 
 | 			case 0xC0: | 
 | 			case 0x80: | 
 | 			case 0x00: | 
 | 				gdbstub_port->rx_brk = 0; | 
 | 				goto try_again; | 
 | 			default: | 
 | 				break; | 
 | 			} | 
 | 		} | 
 |  | 
 | 		gdbstub_port->rx_brk = 0; | 
 | 		gdbstub_io("### GDB Rx %02x (st=%02x) ###\n", ch, st); | 
 | 		*_ch = ch & 0x7f; | 
 | 		return 0; | 
 | 	} | 
 | } | 
 |  | 
 | /* | 
 |  * send a character to the debugger | 
 |  */ | 
 | void gdbstub_io_tx_char(unsigned char ch) | 
 | { | 
 | 	while (*gdbstub_port->_status & SC01STR_TBF) | 
 | 		continue; | 
 |  | 
 | 	if (ch == 0x0a) { | 
 | 		*(u8 *) gdbstub_port->_txb = 0x0d; | 
 | 		while (*gdbstub_port->_status & SC01STR_TBF) | 
 | 			continue; | 
 | 	} | 
 |  | 
 | 	*(u8 *) gdbstub_port->_txb = ch; | 
 | } | 
 |  | 
 | /* | 
 |  * flush the transmission buffers | 
 |  */ | 
 | void gdbstub_io_tx_flush(void) | 
 | { | 
 | 	while (*gdbstub_port->_status & (SC01STR_TBF | SC01STR_TXF)) | 
 | 		continue; | 
 | } |