/* *  linux/drivers/char/serial_amba.c * *  Driver for AMBA serial ports * *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. * *  Copyright 1999 ARM Limited *  Copyright (C) 2000 Deep Blue Solutions Ltd. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA * *  $Id: amba.c,v 1.9.2.2 2002/10/24 09:53:25 rmk Exp $ * * This is a generic driver for ARM AMBA-type serial ports.  They * have a lot of 16550-like features, but are not register compatable. * Note that although they do have CTS, DCD and DSR inputs, they do * not have an RI input, nor do they have DTR or RTS outputs.  If * required, these have to be supplied via some other means (eg, GPIO) * and hooked into this driver. */#include <linux/config.h>#include <linux/module.h>#include <linux/errno.h>#include <linux/signal.h>#include <linux/sched.h>#include <linux/interrupt.h>#include <linux/tty.h>#include <linux/tty_flip.h>#include <linux/major.h>#include <linux/string.h>#include <linux/fcntl.h>#include <linux/ptrace.h>#include <linux/ioport.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/init.h>#include <linux/circ_buf.h>#include <linux/serial.h>#include <linux/console.h>#include <linux/sysrq.h>#include <asm/system.h>#include <asm/io.h>#include <asm/irq.h>#include <asm/uaccess.h>#include <asm/bitops.h>#if defined(CONFIG_SERIAL_AMBA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)#define SUPPORT_SYSRQ#endif#include <linux/serial_core.h>#include <asm/hardware/serial_amba.h>#define UART_NR		2#define SERIAL_AMBA_MAJOR	204#define SERIAL_AMBA_MINOR	16#define SERIAL_AMBA_NR		UART_NR#define CALLOUT_AMBA_NAME	"cuaam"#define CALLOUT_AMBA_MAJOR	205#define CALLOUT_AMBA_MINOR	16#define CALLOUT_AMBA_NR		UART_NRstatic struct tty_driver normal, callout;static struct tty_struct *amba_table[UART_NR];static struct termios *amba_termios[UART_NR], *amba_termios_locked[UART_NR];#ifdef SUPPORT_SYSRQstatic struct console amba_console;#endif#define AMBA_ISR_PASS_LIMIT	256/* * Access macros for the AMBA UARTs */#define UART_GET_INT_STATUS(p)	readb((p)->membase + AMBA_UARTIIR)#define UART_PUT_ICR(p, c)	writel((c), (p)->membase + AMBA_UARTICR)#define UART_GET_FR(p)		readb((p)->membase + AMBA_UARTFR)#define UART_GET_CHAR(p)	readb((p)->membase + AMBA_UARTDR)#define UART_PUT_CHAR(p, c)	writel((c), (p)->membase + AMBA_UARTDR)#define UART_GET_RSR(p)		readb((p)->membase + AMBA_UARTRSR)#define UART_GET_CR(p)		readb((p)->membase + AMBA_UARTCR)#define UART_PUT_CR(p,c)	writel((c), (p)->membase + AMBA_UARTCR)#define UART_GET_LCRL(p)	readb((p)->membase + AMBA_UARTLCR_L)#define UART_PUT_LCRL(p,c)	writel((c), (p)->membase + AMBA_UARTLCR_L)#define UART_GET_LCRM(p)	readb((p)->membase + AMBA_UARTLCR_M)#define UART_PUT_LCRM(p,c)	writel((c), (p)->membase + AMBA_UARTLCR_M)#define UART_GET_LCRH(p)	readb((p)->membase + AMBA_UARTLCR_H)#define UART_PUT_LCRH(p,c)	writel((c), (p)->membase + AMBA_UARTLCR_H)#define UART_RX_DATA(s)		(((s) & AMBA_UARTFR_RXFE) == 0)#define UART_TX_READY(s)	(((s) & AMBA_UARTFR_TXFF) == 0)#define UART_TX_EMPTY(p)	((UART_GET_FR(p) & AMBA_UARTFR_TMSK) == 0)#define UART_DUMMY_RSR_RX	256#define UART_PORT_SIZE		64/* * On the Integrator platform, the port RTS and DTR are provided by * bits in the following SC_CTRLS register bits: *        RTS  DTR *  UART0  7    6 *  UART1  5    4 * * We encode this bit information into port->driver_priv using the * following macros. *///#define PORT_CTRLS(dtrbit,rtsbit)	((1 << dtrbit) | (1 << (16 + rtsbit)))#define PORT_CTRLS_DTR(port)		(1 << (port)->unused[1])#define PORT_CTRLS_RTS(port)		(1 << (port)->unused[0])#define SC_CTRLC	(IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLC_OFFSET)#define SC_CTRLS	(IO_ADDRESS(INTEGRATOR_SC_BASE) + INTEGRATOR_SC_CTRLS_OFFSET)/* * Our private driver data mappings. */#define drv_old_status	driver_privstatic void ambauart_stop_tx(struct uart_port *port, u_int from_tty){	unsigned int cr;	cr = UART_GET_CR(port);	cr &= ~AMBA_UARTCR_TIE;	UART_PUT_CR(port, cr);}static void ambauart_start_tx(struct uart_port *port, u_int nonempty, u_int from_tty){	if (nonempty) {		unsigned int cr;		cr = UART_GET_CR(port);		cr |= AMBA_UARTCR_TIE;		UART_PUT_CR(port, cr);	}}static void ambauart_stop_rx(struct uart_port *port){	unsigned int cr;	cr = UART_GET_CR(port);	cr &= ~(AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE);	UART_PUT_CR(port, cr);}static void ambauart_enable_ms(struct uart_port *port){	unsigned int cr;	cr = UART_GET_CR(port);	cr |= AMBA_UARTCR_MSIE;	UART_PUT_CR(port, cr);}static void#ifdef SUPPORT_SYSRQambauart_rx_chars(struct uart_info *info, struct pt_regs *regs)#elseambauart_rx_chars(struct uart_info *info)#endif{	struct tty_struct *tty = info->tty;	unsigned int status, ch, rsr, max_count = 256;	struct uart_port *port = info->port;	status = UART_GET_FR(port);	while (UART_RX_DATA(status) && max_count--) {		if (tty->flip.count >= TTY_FLIPBUF_SIZE) {			tty->flip.tqueue.routine((void *)tty);			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {				printk(KERN_WARNING "TTY_DONT_FLIP set\n");				return;			}		}		ch = UART_GET_CHAR(port);		*tty->flip.char_buf_ptr = ch;		*tty->flip.flag_buf_ptr = TTY_NORMAL;		port->icount.rx++;		/*		 * Note that the error handling code is		 * out of the main execution path		 */		rsr = UART_GET_RSR(port) | UART_DUMMY_RSR_RX;		if (rsr & AMBA_UARTRSR_ANY) {			if (rsr & AMBA_UARTRSR_BE) {				rsr &= ~(AMBA_UARTRSR_FE | AMBA_UARTRSR_PE);				port->icount.brk++;				if (uart_handle_break(info, &amba_console))					goto ignore_char;			} else if (rsr & AMBA_UARTRSR_PE)				port->icount.parity++;			else if (rsr & AMBA_UARTRSR_FE)				port->icount.frame++;			if (rsr & AMBA_UARTRSR_OE)				port->icount.overrun++;			rsr &= port->read_status_mask;			if (rsr & AMBA_UARTRSR_BE)				*tty->flip.flag_buf_ptr = TTY_BREAK;			else if (rsr & AMBA_UARTRSR_PE)				*tty->flip.flag_buf_ptr = TTY_PARITY;			else if (rsr & AMBA_UARTRSR_FE)				*tty->flip.flag_buf_ptr = TTY_FRAME;		}		if (uart_handle_sysrq_char(info, ch, regs))			goto ignore_char;		if ((rsr & port->ignore_status_mask) == 0) {			tty->flip.flag_buf_ptr++;			tty->flip.char_buf_ptr++;			tty->flip.count++;		}		if ((rsr & AMBA_UARTRSR_OE) &&		    tty->flip.count < TTY_FLIPBUF_SIZE) {			/*			 * Overrun is special, since it's reported			 * immediately, and doesn't affect the current			 * character			 */			*tty->flip.char_buf_ptr++ = 0;			*tty->flip.flag_buf_ptr++ = TTY_OVERRUN;			tty->flip.count++;		}	ignore_char:		status = UART_GET_FR(port);	}	tty_flip_buffer_push(tty);	return;}static void ambauart_tx_chars(struct uart_info *info){	struct uart_port *port = info->port;	int count;	if (port->x_char) {		UART_PUT_CHAR(port, port->x_char);		port->icount.tx++;		port->x_char = 0;		return;	}	if (info->xmit.head == info->xmit.tail	    || info->tty->stopped	    || info->tty->hw_stopped) {		ambauart_stop_tx(port, 0);		return;	}	count = port->fifosize >> 1;	do {		UART_PUT_CHAR(port, info->xmit.buf[info->xmit.tail]);		info->xmit.tail = (info->xmit.tail + 1) & (UART_XMIT_SIZE - 1);		port->icount.tx++;		if (info->xmit.head == info->xmit.tail)			break;	} while (--count > 0);	if (CIRC_CNT(info->xmit.head, info->xmit.tail, UART_XMIT_SIZE) <			WAKEUP_CHARS)		uart_event(info, EVT_WRITE_WAKEUP);	if (info->xmit.head == info->xmit.tail)		ambauart_stop_tx(info->port, 0);}static void ambauart_modem_status(struct uart_info *info){	struct uart_port *port = info->port;	unsigned int status, delta;	UART_PUT_ICR(port, 0);	status = UART_GET_FR(port) & AMBA_UARTFR_MODEM_ANY;	delta = status ^ info->drv_old_status;	info->drv_old_status = status;	if (!delta)		return;	if (delta & AMBA_UARTFR_DCD)		uart_handle_dcd_change(info, status & AMBA_UARTFR_DCD);	if (delta & AMBA_UARTFR_DSR)		port->icount.dsr++;	if (delta & AMBA_UARTFR_CTS)		uart_handle_cts_change(info, status & AMBA_UARTFR_CTS);	wake_up_interruptible(&info->delta_msr_wait);}static void ambauart_int(int irq, void *dev_id, struct pt_regs *regs){	struct uart_info *info = dev_id;	unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;	status = UART_GET_INT_STATUS(info->port);	do {		if (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS))#ifdef SUPPORT_SYSRQ			ambauart_rx_chars(info, regs);#else			ambauart_rx_chars(info);#endif		if (status & AMBA_UARTIIR_TIS)			ambauart_tx_chars(info);		if (status & AMBA_UARTIIR_MIS)			ambauart_modem_status(info);		if (pass_counter-- == 0)			break;		status = UART_GET_INT_STATUS(info->port);	} while (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS |			   AMBA_UARTIIR_TIS));}static u_int ambauart_tx_empty(struct uart_port *port){	return UART_GET_FR(port) & AMBA_UARTFR_BUSY ? 0 : TIOCSER_TEMT;}static u_int ambauart_get_mctrl(struct uart_port *port){	unsigned int result = 0;	unsigned int status;	status = UART_GET_FR(port);	if (status & AMBA_UARTFR_DCD)		result |= TIOCM_CAR;	if (status & AMBA_UARTFR_DSR)		result |= TIOCM_DSR;	if (status & AMBA_UARTFR_CTS)		result |= TIOCM_CTS;	return result;}static void ambauart_set_mctrl(struct uart_port *port, u_int mctrl){	u_int ctrls = 0, ctrlc = 0;	if (mctrl & TIOCM_RTS)		ctrlc |= PORT_CTRLS_RTS(port);	else		ctrls |= PORT_CTRLS_RTS(port);	if (mctrl & TIOCM_DTR)		ctrlc |= PORT_CTRLS_DTR(port);	else		ctrls |= PORT_CTRLS_DTR(port);	__raw_writel(ctrls, SC_CTRLS);	__raw_writel(ctrlc, SC_CTRLC);}