Message-Id: <200710190142.l9J1gfxk003771@goober>
Date:	Fri, 19 Oct 2007 11:42:41 +1000
From:	Greg Ungerer <gerg@...pgear.com>
To:	torvalds@...ux-foundation.org
Cc:	gerg@...inux.org, linux-kernel@...r.kernel.org
Subject: [M68KNOMMU]: new style ColdFire UART driver

A new style serial driver for the Freescale ColdFire UART to replace
the old style one currently in the tree (drivers/serial/mcfserial.c).

Currently this UART is only found in the ColdFire CPU family of parts
(thus I prefixed this patch [M68KNOMMU]).

This has been around for a long while now, tested on all available
platforms.

Signed-off-by: Greg Ungerer <gerg@...inux.org>
---


diff -Naurp linux-2.6.23/drivers/serial/mcf.c linux-2.6.23-uc0/drivers/serial/mcf.c
--- linux-2.6.23/drivers/serial/mcf.c	1970-01-01 10:00:00.000000000 +1000
+++ linux-2.6.23-uc0/drivers/serial/mcf.c	2007-10-19 11:23:15.000000000 +1000
@@ -0,0 +1,653 @@
+/****************************************************************************/
+
+/*
+ *	mcf.c -- Freescale ColdFire UART driver
+ *
+ *	(C) Copyright 2003-2007, Greg Ungerer <gerg@...pgear.com>
+ *
+ * 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.
+ */
+
+/****************************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/console.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <linux/io.h>
+#include <asm/coldfire.h>
+#include <asm/mcfsim.h>
+#include <asm/mcfuart.h>
+#include <asm/nettel.h>
+
+/****************************************************************************/
+
+/*
+ *	Some boards implement the DTR/DCD lines using GPIO lines, most
+ *	don't. Dummy out the access macros for those that don't. Those
+ *	that do should define these macros somewhere in there board
+ *	specific inlude files.
+ */
+#if !defined(mcf_getppdcd)
+#define	mcf_getppdcd(p)		(1)
+#endif
+#if !defined(mcf_getppdtr)
+#define	mcf_getppdtr(p)		(1)
+#endif
+#if !defined(mcf_setppdtr)
+#define	mcf_setppdtr(p, v)	do { } while (0)
+#endif
+
+/****************************************************************************/
+
+/*
+ *	Local per-uart structure.
+ */
+struct mcf_uart {
+	struct uart_port	port;
+	unsigned int		sigs;		/* Local copy of line sigs */
+	unsigned char		imr;		/* Local IMR mirror */
+};
+
+/****************************************************************************/
+
+static unsigned int mcf_tx_empty(struct uart_port *port)
+{
+	return (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXEMPTY) ?
+		TIOCSER_TEMT : 0;
+}
+
+/****************************************************************************/
+
+static unsigned int mcf_get_mctrl(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+	unsigned int sigs;
+
+	spin_lock_irqsave(&port->lock, flags);
+	sigs = (readb(port->membase + MCFUART_UIPR) & MCFUART_UIPR_CTS) ?
+		0 : TIOCM_CTS;
+	sigs |= (pp->sigs & TIOCM_RTS);
+	sigs |= (mcf_getppdcd(port->line) ? TIOCM_CD : 0);
+	sigs |= (mcf_getppdtr(port->line) ? TIOCM_DTR : 0);
+	spin_unlock_irqrestore(&port->lock, flags);
+	return sigs;
+}
+
+/****************************************************************************/
+
+static void mcf_set_mctrl(struct uart_port *port, unsigned int sigs)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	pp->sigs = sigs;
+	mcf_setppdtr(port->line, (sigs & TIOCM_DTR));
+	if (sigs & TIOCM_RTS)
+		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP1);
+	else
+		writeb(MCFUART_UOP_RTS, port->membase + MCFUART_UOP0);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_start_tx(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	pp->imr |= MCFUART_UIR_TXREADY;
+	writeb(pp->imr, port->membase + MCFUART_UIMR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_stop_tx(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	pp->imr &= ~MCFUART_UIR_TXREADY;
+	writeb(pp->imr, port->membase + MCFUART_UIMR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_stop_rx(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	pp->imr &= ~MCFUART_UIR_RXREADY;
+	writeb(pp->imr, port->membase + MCFUART_UIMR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_break_ctl(struct uart_port *port, int break_state)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+	if (break_state == -1)
+		writeb(MCFUART_UCR_CMDBREAKSTART, port->membase + MCFUART_UCR);
+	else
+		writeb(MCFUART_UCR_CMDBREAKSTOP, port->membase + MCFUART_UCR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_enable_ms(struct uart_port *port)
+{
+}
+
+/****************************************************************************/
+
+static int mcf_startup(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* Reset UART, get it into known state... */
+	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
+	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
+
+	/* Enable the UART transmitter and receiver */
+	writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
+		port->membase + MCFUART_UCR);
+
+	/* Enable RX interrupts now */
+	pp->imr = MCFUART_UIR_RXREADY;
+	writeb(pp->imr, port->membase + MCFUART_UIMR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return 0;
+}
+
+/****************************************************************************/
+
+static void mcf_shutdown(struct uart_port *port)
+{
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/* Disable all interrupts now */
+	pp->imr = 0;
+	writeb(pp->imr, port->membase + MCFUART_UIMR);
+
+	/* Disable UART transmitter and receiver */
+	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
+	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_set_termios(struct uart_port *port, struct ktermios *termios,
+	struct ktermios *old)
+{
+	unsigned long flags;
+	unsigned int baud, baudclk;
+	unsigned char mr1, mr2;
+
+	baud = uart_get_baud_rate(port, termios, old, 0, 230400);
+	baudclk = ((MCF_BUSCLK / baud) + 16) / 32;
+
+	mr1 = MCFUART_MR1_RXIRQRDY | MCFUART_MR1_RXERRCHAR;
+	mr2 = 0;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5: mr1 |= MCFUART_MR1_CS5; break;
+	case CS6: mr1 |= MCFUART_MR1_CS6; break;
+	case CS7: mr1 |= MCFUART_MR1_CS7; break;
+	case CS8:
+	default:  mr1 |= MCFUART_MR1_CS8; break;
+	}
+
+	if (termios->c_cflag & PARENB) {
+		if (termios->c_cflag & CMSPAR) {
+			if (termios->c_cflag & PARODD)
+				mr1 |= MCFUART_MR1_PARITYMARK;
+			else
+				mr1 |= MCFUART_MR1_PARITYSPACE;
+		} else {
+			if (termios->c_cflag & PARODD)
+				mr1 |= MCFUART_MR1_PARITYODD;
+			else
+				mr1 |= MCFUART_MR1_PARITYEVEN;
+		}
+	} else {
+		mr1 |= MCFUART_MR1_PARITYNONE;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		mr2 |= MCFUART_MR2_STOP2;
+	else
+		mr2 |= MCFUART_MR2_STOP1;
+
+	if (termios->c_cflag & CRTSCTS) {
+		mr1 |= MCFUART_MR1_RXRTS;
+		mr2 |= MCFUART_MR2_TXCTS;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+	writeb(MCFUART_UCR_CMDRESETRX, port->membase + MCFUART_UCR);
+	writeb(MCFUART_UCR_CMDRESETTX, port->membase + MCFUART_UCR);
+	writeb(MCFUART_UCR_CMDRESETMRPTR, port->membase + MCFUART_UCR);
+	writeb(mr1, port->membase + MCFUART_UMR);
+	writeb(mr2, port->membase + MCFUART_UMR);
+	writeb((baudclk & 0xff00) >> 8, port->membase + MCFUART_UBG1);
+	writeb((baudclk & 0xff), port->membase + MCFUART_UBG2);
+	writeb(MCFUART_UCSR_RXCLKTIMER | MCFUART_UCSR_TXCLKTIMER,
+		port->membase + MCFUART_UCSR);
+	writeb(MCFUART_UCR_RXENABLE | MCFUART_UCR_TXENABLE,
+		port->membase + MCFUART_UCR);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/****************************************************************************/
+
+static void mcf_rx_chars(struct mcf_uart *pp)
+{
+	struct uart_port *port = (struct uart_port *) pp;
+	unsigned char status, ch, flag;
+
+	while ((status = readb(port->membase + MCFUART_USR)) & MCFUART_USR_RXREADY) {
+		ch = readb(port->membase + MCFUART_URB);
+		flag = TTY_NORMAL;
+		port->icount.rx++;
+
+		if (status & MCFUART_USR_RXERR) {
+			writeb(MCFUART_UCR_CMDRESETERR,
+				port->membase + MCFUART_UCR);
+
+			if (status & MCFUART_USR_RXBREAK) {
+				port->icount.brk++;
+				if (uart_handle_break(port))
+					continue;
+			} else if (status & MCFUART_USR_RXPARITY) {
+				port->icount.parity++;
+			} else if (status & MCFUART_USR_RXOVERRUN) {
+				port->icount.overrun++;
+			} else if (status & MCFUART_USR_RXFRAMING) {
+				port->icount.frame++;
+			}
+
+			status &= port->read_status_mask;
+
+			if (status & MCFUART_USR_RXBREAK)
+				flag = TTY_BREAK;
+			else if (status & MCFUART_USR_RXPARITY)
+				flag = TTY_PARITY;
+			else if (status & MCFUART_USR_RXFRAMING)
+				flag = TTY_FRAME;
+		}
+
+		if (uart_handle_sysrq_char(port, ch))
+			continue;
+		uart_insert_char(port, status, MCFUART_USR_RXOVERRUN, ch, flag);
+	}
+
+	tty_flip_buffer_push(port->info->tty);
+}
+
+/****************************************************************************/
+
+static void mcf_tx_chars(struct mcf_uart *pp)
+{
+	struct uart_port *port = (struct uart_port *) pp;
+	struct circ_buf *xmit = &port->info->xmit;
+
+	if (port->x_char) {
+		/* Send special char - probably flow control */
+		writeb(port->x_char, port->membase + MCFUART_UTB);
+		port->x_char = 0;
+		port->icount.tx++;
+		return;
+	}
+
+	while (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY) {
+		if (xmit->head == xmit->tail)
+			break;
+		writeb(xmit->buf[xmit->tail], port->membase + MCFUART_UTB);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE -1);
+		port->icount.tx++;
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	if (xmit->head == xmit->tail) {
+		pp->imr &= ~MCFUART_UIR_TXREADY;
+		writeb(pp->imr, port->membase + MCFUART_UIMR);
+	}
+}
+
+/****************************************************************************/
+
+static irqreturn_t mcf_interrupt(int irq, void *data)
+{
+	struct uart_port *port = data;
+	struct mcf_uart *pp = (struct mcf_uart *) port;
+	unsigned int isr;
+
+	isr = readb(port->membase + MCFUART_UISR) & pp->imr;
+	if (isr & MCFUART_UIR_RXREADY)
+		mcf_rx_chars(pp);
+	if (isr & MCFUART_UIR_TXREADY)
+		mcf_tx_chars(pp);
+	return IRQ_HANDLED;
+}
+
+/****************************************************************************/
+
+static void mcf_config_port(struct uart_port *port, int flags)
+{
+	port->type = PORT_MCF;
+
+	/* Clear mask, so no surprise interrupts. */
+	writeb(0, port->membase + MCFUART_UIMR);
+
+	if (request_irq(port->irq, mcf_interrupt, IRQF_DISABLED, "UART", port))
+		printk(KERN_ERR "MCF: unable to attach ColdFire UART %d "
+			"interrupt vector=%d\n", port->line, port->irq);
+}
+
+/****************************************************************************/
+
+static const char *mcf_type(struct uart_port *port)
+{
+	return (port->type == PORT_MCF) ? "ColdFire UART" : NULL;
+}
+
+/****************************************************************************/
+
+static int mcf_request_port(struct uart_port *port)
+{
+	/* UARTs always present */
+	return 0;
+}
+
+/****************************************************************************/
+
+static void mcf_release_port(struct uart_port *port)
+{
+	/* Nothing to release... */
+}
+
+/****************************************************************************/
+
+static int mcf_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_MCF))
+		return -EINVAL;
+	return 0;
+}
+
+/****************************************************************************/
+
+/*
+ *	Define the basic serial functions we support.
+ */
+static struct uart_ops mcf_uart_ops = {
+	.tx_empty	= mcf_tx_empty,
+	.get_mctrl	= mcf_get_mctrl,
+	.set_mctrl	= mcf_set_mctrl,
+	.start_tx	= mcf_start_tx,
+	.stop_tx	= mcf_stop_tx,
+	.stop_rx	= mcf_stop_rx,
+	.enable_ms	= mcf_enable_ms,
+	.break_ctl	= mcf_break_ctl,
+	.startup	= mcf_startup,
+	.shutdown	= mcf_shutdown,
+	.set_termios	= mcf_set_termios,
+	.type		= mcf_type,
+	.request_port	= mcf_request_port,
+	.release_port	= mcf_release_port,
+	.config_port	= mcf_config_port,
+	.verify_port	= mcf_verify_port,
+};
+
+static struct mcf_uart mcf_ports[3];
+
+#define	MCF_MAXPORTS	(sizeof(mcf_ports) / sizeof(struct mcf_uart))
+
+/****************************************************************************/
+#if defined(CONFIG_SERIAL_MCF_CONSOLE)
+/****************************************************************************/
+
+int __init early_mcf_setup(struct mcf_platform_uart *platp)
+{
+	struct uart_port *port;
+	int i;
+
+	for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
+		port = &mcf_ports[i].port;
+
+		port->line = i;
+		port->type = PORT_MCF;
+		port->mapbase = platp[i].mapbase;
+		port->membase = (platp[i].membase) ? platp[i].membase :
+			(unsigned char __iomem *) port->mapbase;
+		port->iotype = SERIAL_IO_MEM;
+		port->irq = platp[i].irq;
+		port->uartclk = MCF_BUSCLK;
+		port->flags = ASYNC_BOOT_AUTOCONF;
+		port->ops = &mcf_uart_ops;
+	}
+
+	return 0;
+}
+
+/****************************************************************************/
+
+static void mcf_console_putc(struct console *co, const char c)
+{
+	struct uart_port *port = &(mcf_ports + co->index)->port;
+	int i;
+
+	for (i = 0; (i < 0x10000); i++) {
+		if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
+			break;
+	}
+	writeb(c, port->membase + MCFUART_UTB);
+	for (i = 0; (i < 0x10000); i++) {
+		if (readb(port->membase + MCFUART_USR) & MCFUART_USR_TXREADY)
+			break;
+	}
+}
+
+/****************************************************************************/
+
+static void mcf_console_write(struct console *co, const char *s, unsigned int count)
+{
+	for (; (count); count--, s++) {
+		mcf_console_putc(co, *s);
+		if (*s == '\n')
+			mcf_console_putc(co, '\r');
+	}
+}
+
+/****************************************************************************/
+
+static int __init mcf_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = CONFIG_SERIAL_MCF_BAUDRATE;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	if ((co->index >= 0) && (co->index <= MCF_MAXPORTS))
+		co->index = 0;
+	port = &mcf_ports[co->index].port;
+	if (port->membase == 0)
+		return -ENODEV;
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+/****************************************************************************/
+
+static struct uart_driver mcf_driver;
+
+static struct console mcf_console = {
+	.name		= "ttyS",
+	.write		= mcf_console_write,
+	.device		= uart_console_device,
+	.setup		= mcf_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &mcf_driver,
+};
+
+static int __init mcf_console_init(void)
+{
+	register_console(&mcf_console);
+	return 0;
+}
+
+console_initcall(mcf_console_init);
+
+#define	MCF_CONSOLE	&mcf_console
+
+/****************************************************************************/
+#else
+/****************************************************************************/
+
+#define	MCF_CONSOLE	NULL
+
+/****************************************************************************/
+#endif /* CONFIG_MCF_CONSOLE */
+/****************************************************************************/
+
+/*
+ *	Define the mcf UART driver structure.
+ */
+static struct uart_driver mcf_driver = {
+	.owner		= THIS_MODULE,
+	.driver_name	= "mcf",
+	.dev_name	= "ttyS",
+	.major		= TTY_MAJOR,
+	.minor		= 64,
+	.nr		= MCF_MAXPORTS,
+	.cons		= MCF_CONSOLE,
+};
+
+/****************************************************************************/
+
+static int __devinit mcf_probe(struct platform_device *pdev)
+{
+	struct mcf_platform_uart *platp = pdev->dev.platform_data;
+	struct uart_port *port;
+	int i;
+
+	for (i = 0; ((i < MCF_MAXPORTS) && (platp[i].mapbase)); i++) {
+		port = &mcf_ports[i].port;
+
+		port->line = i;
+		port->type = PORT_MCF;
+		port->mapbase = platp[i].mapbase;
+		port->membase = (platp[i].membase) ? platp[i].membase :
+			(unsigned char __iomem *) platp[i].mapbase;
+		port->iotype = SERIAL_IO_MEM;
+		port->irq = platp[i].irq;
+		port->uartclk = MCF_BUSCLK;
+		port->ops = &mcf_uart_ops;
+		port->flags = ASYNC_BOOT_AUTOCONF;
+
+		uart_add_one_port(&mcf_driver, port);
+	}
+
+	return 0;
+}
+
+/****************************************************************************/
+
+static int mcf_remove(struct platform_device *pdev)
+{
+	struct uart_port *port;
+	int i;
+
+	for (i = 0; (i < MCF_MAXPORTS); i++) {
+		port = &mcf_ports[i].port;
+		if (port)
+			uart_remove_one_port(&mcf_driver, port);
+	}
+
+	return 0;
+}
+
+/****************************************************************************/
+
+static struct platform_driver mcf_platform_driver = {
+	.probe		= mcf_probe,
+	.remove		= __devexit_p(mcf_remove),
+	.driver		= {
+		.name	= "mcfuart",
+		.owner	= THIS_MODULE,
+	},
+};
+
+/****************************************************************************/
+
+static int __init mcf_init(void)
+{
+	int rc;
+
+	printk("ColdFire internal UART serial driver\n");
+
+	rc = uart_register_driver(&mcf_driver);
+	if (rc)
+		return rc;
+	rc = platform_driver_register(&mcf_platform_driver);
+	if (rc)
+		return rc;
+	return 0;
+}
+
+/****************************************************************************/
+
+static void __exit mcf_exit(void)
+{
+	platform_driver_unregister(&mcf_platform_driver);
+	uart_unregister_driver(&mcf_driver);
+}
+
+/****************************************************************************/
+
+module_init(mcf_init);
+module_exit(mcf_exit);
+
+MODULE_AUTHOR("Greg Ungerer <gerg@...pgear.com>");
+MODULE_DESCRIPTION("Freescale ColdFire UART driver");
+MODULE_LICENSE("GPL");
+
+/****************************************************************************/
-
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