[ARM] 4332/2: KS8695: Serial driver

A driver for the KS8695 internal UART.

Based on the 2.6.9 driver from Micrel.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 675 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index a6f5bfb..315ea99 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -359,6 +359,23 @@ config SERIAL_ATMEL_TTYAT
 
 	  Say Y if you have an external 8250/16C550 UART.  If unsure, say N.
 
+config SERIAL_KS8695
+	bool "Micrel KS8695 (Centaur) serial port support"
+	depends on ARCH_KS8695
+	select SERIAL_CORE
+	help
+	  This selects the Micrel Centaur KS8695 UART.  Say Y here.
+
+config SERIAL_KS8695_CONSOLE
+	bool "Support for console on KS8695 (Centaur) serial port"
+	depends on SERIAL_KS8695=y
+	select SERIAL_CORE_CONSOLE
+	help
+	  Say Y here if you wish to use a KS8695 (Centaur) UART as the
+	  system console (the system console is the device which
+	  receives all kernel messages and warnings and which allows
+	  logins in single user mode).
+
 config SERIAL_CLPS711X
 	tristate "CLPS711X serial port support"
 	depends on ARM && ARCH_CLPS711X
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 4959bcb..08ad0d9 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -61,3 +61,4 @@ obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
 obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
+obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
diff --git a/drivers/serial/serial_ks8695.c b/drivers/serial/serial_ks8695.c
new file mode 100644
index 0000000..c5346d6
--- /dev/null
+++ b/drivers/serial/serial_ks8695.c
@@ -0,0 +1,657 @@
+/*
+ *  drivers/serial/serial_ks8695.c
+ *
+ *  Driver for KS8695 serial ports
+ *
+ *  Based on drivers/serial/serial_amba.c, by Kam Lee.
+ *
+ *  Copyright 2002-2005 Micrel Inc.
+ *
+ * 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/module.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/device.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+
+#include <asm/arch/regs-uart.h>
+#include <asm/arch/regs-irq.h>
+
+#if defined(CONFIG_SERIAL_KS8695_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial_core.h>
+
+
+#define SERIAL_KS8695_MAJOR	204
+#define SERIAL_KS8695_MINOR	16
+#define SERIAL_KS8695_DEVNAME	"ttyAM"
+
+#define SERIAL_KS8695_NR	1
+
+/*
+ * Access macros for the KS8695 UART
+ */
+#define UART_GET_CHAR(p)	(__raw_readl((p)->membase + KS8695_URRB) & 0xFF)
+#define UART_PUT_CHAR(p, c)	__raw_writel((c), (p)->membase + KS8695_URTH)
+#define UART_GET_FCR(p)		__raw_readl((p)->membase + KS8695_URFC)
+#define UART_PUT_FCR(p, c)	__raw_writel((c), (p)->membase + KS8695_URFC)
+#define UART_GET_MSR(p)		__raw_readl((p)->membase + KS8695_URMS)
+#define UART_GET_LSR(p)		__raw_readl((p)->membase + KS8695_URLS)
+#define UART_GET_LCR(p)		__raw_readl((p)->membase + KS8695_URLC)
+#define UART_PUT_LCR(p, c)	__raw_writel((c), (p)->membase + KS8695_URLC)
+#define UART_GET_MCR(p)		__raw_readl((p)->membase + KS8695_URMC)
+#define UART_PUT_MCR(p, c)	__raw_writel((c), (p)->membase + KS8695_URMC)
+#define UART_GET_BRDR(p)	__raw_readl((p)->membase + KS8695_URBD)
+#define UART_PUT_BRDR(p, c)	__raw_writel((c), (p)->membase + KS8695_URBD)
+
+#define KS8695_CLR_TX_INT()	__raw_writel(1 << KS8695_IRQ_UART_TX, KS8695_IRQ_VA + KS8695_INTST)
+
+#define UART_DUMMY_LSR_RX	0x100
+#define UART_PORT_SIZE		(KS8695_USR - KS8695_URRB + 4)
+
+#define tx_enabled(port) ((port)->unused[0])
+#define rx_enabled(port) ((port)->unused[1])
+
+
+#ifdef SUPPORT_SYSRQ
+static struct console ks8695_console;
+#endif
+
+static void ks8695uart_stop_tx(struct uart_port *port)
+{
+	if (tx_enabled(port)) {
+		disable_irq(KS8695_IRQ_UART_TX);
+		tx_enabled(port) = 0;
+	}
+}
+
+static void ks8695uart_start_tx(struct uart_port *port)
+{
+	if (!tx_enabled(port)) {
+		enable_irq(KS8695_IRQ_UART_TX);
+		tx_enabled(port) = 1;
+	}
+}
+
+static void ks8695uart_stop_rx(struct uart_port *port)
+{
+	if (rx_enabled(port)) {
+		disable_irq(KS8695_IRQ_UART_RX);
+		rx_enabled(port) = 0;
+	}
+}
+
+static void ks8695uart_enable_ms(struct uart_port *port)
+{
+	enable_irq(KS8695_IRQ_UART_MODEM_STATUS);
+}
+
+static void ks8695uart_disable_ms(struct uart_port *port)
+{
+	disable_irq(KS8695_IRQ_UART_MODEM_STATUS);
+}
+
+static irqreturn_t ks8695uart_rx_chars(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct tty_struct *tty = port->info->tty;
+	unsigned int status, ch, lsr, flg, max_count = 256;
+
+	status = UART_GET_LSR(port);		/* clears pending LSR interrupts */
+	while ((status & URLS_URDR) && max_count--) {
+		ch = UART_GET_CHAR(port);
+		flg = TTY_NORMAL;
+
+		port->icount.rx++;
+
+		/*
+		 * Note that the error handling code is
+		 * out of the main execution path
+		 */
+		lsr = UART_GET_LSR(port) | UART_DUMMY_LSR_RX;
+		if (unlikely(lsr & (URLS_URBI | URLS_URPE | URLS_URFE | URLS_URROE))) {
+			if (lsr & URLS_URBI) {
+				lsr &= ~(URLS_URFE | URLS_URPE);
+				port->icount.brk++;
+				if (uart_handle_break(port))
+					goto ignore_char;
+			}
+			if (lsr & URLS_URPE)
+				port->icount.parity++;
+			if (lsr & URLS_URFE)
+				port->icount.frame++;
+			if (lsr & URLS_URROE)
+				port->icount.overrun++;
+
+			lsr &= port->read_status_mask;
+
+			if (lsr & URLS_URBI)
+				flg = TTY_BREAK;
+			else if (lsr & URLS_URPE)
+				flg = TTY_PARITY;
+			else if (lsr & URLS_URFE)
+				flg = TTY_FRAME;
+		}
+
+		if (uart_handle_sysrq_char(port, ch))
+			goto ignore_char;
+
+		uart_insert_char(port, lsr, URLS_URROE, ch, flg);
+
+ignore_char:
+		status = UART_GET_LSR(port);
+	}
+	tty_flip_buffer_push(tty);
+
+	return IRQ_HANDLED;
+}
+
+
+static irqreturn_t ks8695uart_tx_chars(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	struct circ_buf *xmit = &port->info->xmit;
+	unsigned int count;
+
+	if (port->x_char) {
+		KS8695_CLR_TX_INT();
+		UART_PUT_CHAR(port, port->x_char);
+		port->icount.tx++;
+		port->x_char = 0;
+		return IRQ_HANDLED;
+	}
+
+	if (uart_tx_stopped(port) || uart_circ_empty(xmit)) {
+		ks8695uart_stop_tx(port);
+		return IRQ_HANDLED;
+	}
+
+	count = 16;	/* fifo size */
+	while (!uart_circ_empty(xmit) && (count-- > 0)) {
+		KS8695_CLR_TX_INT();
+		UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
+
+		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 (uart_circ_empty(xmit))
+		ks8695uart_stop_tx(port);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t ks8695uart_modem_status(int irq, void *dev_id)
+{
+	struct uart_port *port = dev_id;
+	unsigned int status;
+
+	/*
+	 * clear modem interrupt by reading MSR
+	 */
+	status = UART_GET_MSR(port);
+
+	if (status & URMS_URDDCD)
+		uart_handle_dcd_change(port, status & URMS_URDDCD);
+
+	if (status & URMS_URDDST)
+		port->icount.dsr++;
+
+	if (status & URMS_URDCTS)
+		uart_handle_cts_change(port, status & URMS_URDCTS);
+
+	if (status & URMS_URTERI)
+		port->icount.rng++;
+
+	wake_up_interruptible(&port->info->delta_msr_wait);
+
+	return IRQ_HANDLED;
+}
+
+static unsigned int ks8695uart_tx_empty(struct uart_port *port)
+{
+	return (UART_GET_LSR(port) & URLS_URTE) ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int ks8695uart_get_mctrl(struct uart_port *port)
+{
+	unsigned int result = 0;
+	unsigned int status;
+
+	status = UART_GET_MSR(port);
+	if (status & URMS_URDCD)
+		result |= TIOCM_CAR;
+	if (status & URMS_URDSR)
+		result |= TIOCM_DSR;
+	if (status & URMS_URCTS)
+		result |= TIOCM_CTS;
+	if (status & URMS_URRI)
+		result |= TIOCM_RI;
+
+	return result;
+}
+
+static void ks8695uart_set_mctrl(struct uart_port *port, u_int mctrl)
+{
+	unsigned int mcr;
+
+	mcr = UART_GET_MCR(port);
+	if (mctrl & TIOCM_RTS)
+		mcr |= URMC_URRTS;
+	else
+		mcr &= ~URMC_URRTS;
+
+	if (mctrl & TIOCM_DTR)
+		mcr |= URMC_URDTR;
+	else
+		mcr &= ~URMC_URDTR;
+
+	UART_PUT_MCR(port, mcr);
+}
+
+static void ks8695uart_break_ctl(struct uart_port *port, int break_state)
+{
+	unsigned int lcr;
+
+	lcr = UART_GET_LCR(port);
+
+	if (break_state == -1)
+		lcr |= URLC_URSBC;
+	else
+		lcr &= ~URLC_URSBC;
+
+	UART_PUT_LCR(port, lcr);
+}
+
+static int ks8695uart_startup(struct uart_port *port)
+{
+	int retval;
+
+	set_irq_flags(KS8695_IRQ_UART_TX, IRQF_VALID | IRQF_NOAUTOEN);
+	tx_enabled(port) = 0;
+	rx_enabled(port) = 1;
+
+	/*
+	 * Allocate the IRQ
+	 */
+	retval = request_irq(KS8695_IRQ_UART_TX, ks8695uart_tx_chars, IRQF_DISABLED, "UART TX", port);
+	if (retval)
+		goto err_tx;
+
+	retval = request_irq(KS8695_IRQ_UART_RX, ks8695uart_rx_chars, IRQF_DISABLED, "UART RX", port);
+	if (retval)
+		goto err_rx;
+
+	retval = request_irq(KS8695_IRQ_UART_LINE_STATUS, ks8695uart_rx_chars, IRQF_DISABLED, "UART LineStatus", port);
+	if (retval)
+		return err_ls;
+
+	retval = request_irq(KS8695_IRQ_UART_MODEM_STATUS, ks8695uart_modem_status, IRQF_DISABLED, "UART ModemStatus", port);
+	if (retval)
+		return err_ms;
+
+	return 0;
+
+err_ms:
+	free_irq(KS8695_IRQ_UART_LINE_STATUS, port);
+err_ls:
+	free_irq(KS8695_IRQ_UART_RX, port);
+err_rx:
+	free_irq(KS8695_IRQ_UART_TX, port);
+err_tx:
+	return retval;
+}
+
+static void ks8695uart_shutdown(struct uart_port *port)
+{
+	/*
+	 * Free the interrupt
+	 */
+	free_irq(KS8695_IRQ_UART_RX, port);
+	free_irq(KS8695_IRQ_UART_TX, port);
+	free_irq(KS8695_IRQ_UART_MODEM_STATUS, port);
+	free_irq(KS8695_IRQ_UART_LINE_STATUS, port);
+
+	/* disable break condition and fifos */
+	UART_PUT_LCR(port, UART_GET_LCR(port) & ~URLC_URSBC);
+	UART_PUT_FCR(port, UART_GET_FCR(port) & ~URFC_URFE);
+}
+
+static void ks8695uart_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old)
+{
+	unsigned int lcr, fcr = 0;
+	unsigned long flags;
+	unsigned int baud, quot;
+
+	/*
+	 * Ask the core to calculate the divisor for us.
+	 */
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+	quot = uart_get_divisor(port, baud);
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		lcr = URCL_5;
+		break;
+	case CS6:
+		lcr = URCL_6;
+		break;
+	case CS7:
+		lcr = URCL_7;
+		break;
+	default:
+		lcr = URCL_8;
+		break;
+	}
+
+	/* stop bits */
+	if (termios->c_cflag & CSTOPB)
+		lcr |= URLC_URSB;
+
+	/* parity */
+	if (termios->c_cflag & PARENB) {
+		if (termios->c_cflag & CMSPAR) {	/* Mark or Space parity */
+			if (termios->c_cflag & PARODD)
+				lcr |= URPE_MARK;
+			else
+				lcr |= URPE_SPACE;
+		}
+		else if (termios->c_cflag & PARODD)
+			lcr |= URPE_ODD;
+		else
+			lcr |= URPE_EVEN;
+	}
+
+	if (port->fifosize > 1)
+		fcr = URFC_URFRT_8 | URFC_URTFR | URFC_URRFR | URFC_URFE;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	/*
+	 * Update the per-port timeout.
+	 */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	port->read_status_mask = URLS_URROE;
+	if (termios->c_iflag & INPCK)
+		port->read_status_mask |= (URLS_URFE | URLS_URPE);
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		port->read_status_mask |= URLS_URBI;
+
+	/*
+	 * Characters to ignore
+	 */
+	port->ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		port->ignore_status_mask |= (URLS_URFE | URLS_URPE);
+	if (termios->c_iflag & IGNBRK) {
+		port->ignore_status_mask |= URLS_URBI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			port->ignore_status_mask |= URLS_URROE;
+	}
+
+	/*
+	 * Ignore all characters if CREAD is not set.
+	 */
+	if ((termios->c_cflag & CREAD) == 0)
+		port->ignore_status_mask |= UART_DUMMY_LSR_RX;
+
+	/* first, disable everything */
+	if (UART_ENABLE_MS(port, termios->c_cflag))
+		ks8695uart_enable_ms(port);
+	else
+		ks8695uart_disable_ms(port);
+
+	/* Set baud rate */
+	UART_PUT_BRDR(port, quot);
+
+	UART_PUT_LCR(port, lcr);
+	UART_PUT_FCR(port, fcr);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *ks8695uart_type(struct uart_port *port)
+{
+	return port->type == PORT_KS8695 ? "KS8695" : NULL;
+}
+
+/*
+ * Release the memory region(s) being used by 'port'
+ */
+static void ks8695uart_release_port(struct uart_port *port)
+{
+	release_mem_region(port->mapbase, UART_PORT_SIZE);
+}
+
+/*
+ * Request the memory region(s) being used by 'port'
+ */
+static int ks8695uart_request_port(struct uart_port *port)
+{
+	return request_mem_region(port->mapbase, UART_PORT_SIZE,
+			"serial_ks8695") != NULL ? 0 : -EBUSY;
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void ks8695uart_config_port(struct uart_port *port, int flags)
+{
+	if (flags & UART_CONFIG_TYPE) {
+		port->type = PORT_KS8695;
+		ks8695uart_request_port(port);
+	}
+}
+
+/*
+ * verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int ks8695uart_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	int ret = 0;
+
+	if (ser->type != PORT_UNKNOWN && ser->type != PORT_KS8695)
+		ret = -EINVAL;
+	if (ser->irq != port->irq)
+		ret = -EINVAL;
+	if (ser->baud_base < 9600)
+		ret = -EINVAL;
+	return ret;
+}
+
+static struct uart_ops ks8695uart_pops = {
+	.tx_empty	= ks8695uart_tx_empty,
+	.set_mctrl	= ks8695uart_set_mctrl,
+	.get_mctrl	= ks8695uart_get_mctrl,
+	.stop_tx	= ks8695uart_stop_tx,
+	.start_tx	= ks8695uart_start_tx,
+	.stop_rx	= ks8695uart_stop_rx,
+	.enable_ms	= ks8695uart_enable_ms,
+	.break_ctl	= ks8695uart_break_ctl,
+	.startup	= ks8695uart_startup,
+	.shutdown	= ks8695uart_shutdown,
+	.set_termios	= ks8695uart_set_termios,
+	.type		= ks8695uart_type,
+	.release_port	= ks8695uart_release_port,
+	.request_port	= ks8695uart_request_port,
+	.config_port	= ks8695uart_config_port,
+	.verify_port	= ks8695uart_verify_port,
+};
+
+static struct uart_port ks8695uart_ports[SERIAL_KS8695_NR] = {
+	{
+		.membase	= (void *) KS8695_UART_VA,
+		.mapbase	= KS8695_UART_VA,
+		.iotype		= SERIAL_IO_MEM,
+		.irq		= KS8695_IRQ_UART_TX,
+		.uartclk	= CLOCK_TICK_RATE * 16,
+		.fifosize	= 16,
+		.ops		= &ks8695uart_pops,
+		.flags		= ASYNC_BOOT_AUTOCONF,
+		.line		= 0,
+	}
+};
+
+#ifdef CONFIG_SERIAL_KS8695_CONSOLE
+static void ks8695_console_putchar(struct uart_port *port, int ch)
+{
+	while (!(UART_GET_LSR(port) & URLS_URTHRE))
+		barrier();
+
+	UART_PUT_CHAR(port, ch);
+}
+
+static void ks8695_console_write(struct console *co, const char *s, u_int count)
+{
+	struct uart_port *port = ks8695uart_ports + co->index;
+
+	uart_console_write(port, s, count, ks8695_console_putchar);
+}
+
+static void __init ks8695_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits)
+{
+	unsigned int lcr;
+
+	lcr = UART_GET_LCR(port);
+
+	switch (lcr & URLC_PARITY) {
+		case URPE_ODD:
+			*parity = 'o';
+			break;
+		case URPE_EVEN:
+			*parity = 'e';
+			break;
+		default:
+			*parity = 'n';
+	}
+
+	switch (lcr & URLC_URCL) {
+		case URCL_5:
+			*bits = 5;
+			break;
+		case URCL_6:
+			*bits = 6;
+			break;
+		case URCL_7:
+			*bits = 7;
+			break;
+		default:
+			*bits = 8;
+	}
+
+	*baud = port->uartclk / (UART_GET_BRDR(port) & 0x0FFF);
+	*baud /= 16;
+	*baud &= 0xFFFFFFF0;
+}
+
+static int __init ks8695_console_setup(struct console *co, char *options)
+{
+	struct uart_port *port;
+	int baud = 115200;
+	int bits = 8;
+	int parity = 'n';
+	int flow = 'n';
+
+	/*
+	 * Check whether an invalid uart number has been specified, and
+	 * if so, search for the first available port that does have
+	 * console support.
+	 */
+	port = uart_get_console(ks8695uart_ports, SERIAL_KS8695_NR, co);
+
+	if (options)
+		uart_parse_options(options, &baud, &parity, &bits, &flow);
+	else
+		ks8695_console_get_options(port, &baud, &parity, &bits);
+
+	return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+extern struct uart_driver ks8695_reg;
+
+static struct console ks8695_console = {
+	.name		= SERIAL_KS8695_DEVNAME,
+	.write		= ks8695_console_write,
+	.device		= uart_console_device,
+	.setup		= ks8695_console_setup,
+	.flags		= CON_PRINTBUFFER,
+	.index		= -1,
+	.data		= &ks8695_reg,
+};
+
+static int __init ks8695_console_init(void)
+{
+	register_console(&ks8695_console);
+	return 0;
+}
+
+console_initcall(ks8695_console_init);
+
+#define KS8695_CONSOLE	&ks8695_console
+#else
+#define KS8695_CONSOLE	NULL
+#endif
+
+static struct uart_driver ks8695_reg = {
+	.owner			= THIS_MODULE,
+	.driver_name		= "serial_ks8695",
+	.dev_name		= SERIAL_KS8695_DEVNAME,
+	.major			= SERIAL_KS8695_MAJOR,
+	.minor			= SERIAL_KS8695_MINOR,
+	.nr			= SERIAL_KS8695_NR,
+	.cons			= KS8695_CONSOLE,
+};
+
+static int __init ks8695uart_init(void)
+{
+	int i, ret;
+
+	printk(KERN_INFO "Serial: Micrel KS8695 UART driver\n");
+
+	ret = uart_register_driver(&ks8695_reg);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < SERIAL_KS8695_NR; i++)
+		uart_add_one_port(&ks8695_reg, &ks8695uart_ports[0]);
+
+	return 0;
+}
+
+static void __exit ks8695uart_exit(void)
+{
+	int i;
+
+	for (i = 0; i < SERIAL_KS8695_NR; i++)
+		uart_remove_one_port(&ks8695_reg, &ks8695uart_ports[0]);
+	uart_unregister_driver(&ks8695_reg);
+}
+
+module_init(ks8695uart_init);
+module_exit(ks8695uart_exit);
+
+MODULE_DESCRIPTION("KS8695 serial port driver");
+MODULE_AUTHOR("Micrel Inc.");
+MODULE_LICENSE("GPL");