Add support for aspeed hardware

1 files changed, 1511 insertions, 0 deletions

diff --git a/drivers/serial/ast1070_dma_uart.c b/drivers/serial/ast1070_dma_uart.c
new file mode 100644
index 000000000000..16eb3c5f2a29
--- /dev/null
+++ b/drivers/serial/ast1070_dma_uart.c
@@ -0,0 +1,1511 @@
+/********************************************************************************
+* File Name     : ast1070_dma_uart.c
+* 
+* Copyright (C) 2012-2020  ASPEED Technology 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. 
+* 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 
+********************************************************************************/
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_reg.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/serial_8250.h>
+#include <linux/nmi.h>
+#include <linux/mutex.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include "8250.h"
+#include <linux/dma-mapping.h>
+#include <linux/miscdevice.h>
+#include <plat/regs-uart-dma.h>
+#include <mach/ast-uart-dma.h>
+
+//#define CONFIG_UART_DMA_DEBUG
+
+#ifdef CONFIG_UART_DMA_DEBUG
+	#define DBG(fmt, args...) printk("%s() " fmt, __FUNCTION__, ## args)
+#else
+	#define DBG(fmt, args...)
+#endif
+
+/*
+ * Configuration:
+ *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
+ *                is unsafe when used on edge-triggered interrupts.
+ */
+static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
+
+static unsigned int nr_uarts = CONFIG_AST_RUNTIME_DMA_UARTS;
+
+/*
+ * Debugging.
+ */
+#if 0
+#define DEBUG_AUTOCONF(fmt...)	printk(fmt)
+#else
+#define DEBUG_AUTOCONF(fmt...)	do { } while (0)
+#endif
+
+#if 0
+#define DEBUG_INTR(fmt...)	printk(fmt)
+#else
+#define DEBUG_INTR(fmt...)	do { } while (0)
+#endif
+
+#define PASS_LIMIT	256
+
+#include <asm/serial.h>
+
+
+#define UART_DMA_NR		CONFIG_AST_NR_DMA_UARTS
+
+struct ast_uart_port {
+	struct uart_port	port;
+	unsigned short		capabilities;	/* port capabilities */
+	unsigned short		bugs;		/* port bugs */
+	unsigned int		tx_loadsz;	/* transmit fifo load size */
+	unsigned char		acr;
+	unsigned char		ier;
+	unsigned char		lcr;
+	unsigned char		mcr;
+	unsigned char		mcr_mask;	/* mask of user bits */
+	unsigned char		mcr_force;	/* mask of forced bits */
+	struct circ_buf		rx_dma_buf;
+	struct circ_buf		tx_dma_buf;
+	dma_addr_t			dma_rx_addr;	/* Mapped ADMA descr. table */
+	dma_addr_t			dma_tx_addr;	/* Mapped ADMA descr. table */
+	unsigned int 	dma_buf_size;	//total allocation dma size ..
+	struct tasklet_struct	rx_tasklet;
+	int rx_tasklet_done;
+	struct tasklet_struct	tx_tasklet;
+	spinlock_t lock;
+	int tx_done;
+	int tx_count;
+	/*
+	 * Some bits in registers are cleared on a read, so they must
+	 * be saved whenever the register is read but the bits will not
+	 * be immediately processed.
+	 */
+#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
+	unsigned char		lsr_saved_flags;
+#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
+	unsigned char		msr_saved_flags;
+
+	/*
+	 * We provide a per-port pm hook.
+	 */
+	void			(*pm)(struct uart_port *port,
+				      unsigned int state, unsigned int old);
+};
+
+static struct ast_uart_port ast_uart_ports[UART_DMA_NR];
+
+static inline struct ast_uart_port *
+to_ast_dma_uart_port(struct uart_port *uart)
+{
+	return container_of(uart, struct ast_uart_port, port);
+}
+
+struct irq_info {
+	spinlock_t		lock;
+	struct ast_uart_port *up;
+};
+
+static struct irq_info ast_uart_irq[1];
+static DEFINE_MUTEX(ast_uart_mutex);
+
+/*
+ * Here we define the default xmit fifo size used for each type of UART.
+ */
+static const struct serial8250_config uart_config[] = {
+	[PORT_UNKNOWN] = {
+		.name		= "unknown",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_8250] = {
+		.name		= "8250",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16450] = {
+		.name		= "16450",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16550] = {
+		.name		= "16550",
+		.fifo_size	= 1,
+		.tx_loadsz	= 1,
+	},
+	[PORT_16550A] = {
+		.name		= "16550A",
+		.fifo_size	= 16,
+		.tx_loadsz	= 16,
+		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 | UART_FCR_DMA_SELECT,
+		.flags		= UART_CAP_FIFO,
+	},
+};
+
+/* sane hardware needs no mapping */
+#define map_8250_in_reg(up, offset) (offset)
+#define map_8250_out_reg(up, offset) (offset)
+
+void ast_uart_unregister_port(int line);
+int ast_uart_register_port(struct uart_port *port);
+
+static unsigned int serial_in(struct ast_uart_port *up, int offset)
+{
+	offset = map_8250_in_reg(up, offset) << up->port.regshift;
+
+		return readb(up->port.membase + offset);
+}
+
+static void
+serial_out(struct ast_uart_port *up, int offset, int value)
+{
+	/* Save the offset before it's remapped */
+	offset = map_8250_out_reg(up, offset) << up->port.regshift;
+
+		writeb(value, up->port.membase + offset);
+}
+
+
+/*
+ * We used to support using pause I/O for certain machines.  We
+ * haven't supported this for a while, but just in case it's badly
+ * needed for certain old 386 machines, I've left these #define's
+ * in....
+ */
+#define serial_inp(up, offset)		serial_in(up, offset)
+#define serial_outp(up, offset, value)	serial_out(up, offset, value)
+
+/* Uart divisor latch read */
+static inline int _serial_dl_read(struct ast_uart_port *up)
+{
+	return serial_inp(up, UART_DLL) | serial_inp(up, UART_DLM) << 8;
+}
+
+/* Uart divisor latch write */
+static inline void _serial_dl_write(struct ast_uart_port *up, int value)
+{
+	serial_outp(up, UART_DLL, value & 0xff);
+	serial_outp(up, UART_DLM, value >> 8 & 0xff);
+}
+
+#define serial_dl_read(up) _serial_dl_read(up)
+#define serial_dl_write(up, value) _serial_dl_write(up, value)
+
+static void ast_uart_tx_tasklet_func(unsigned long data)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port((struct uart_port *)data);
+	struct circ_buf *xmit = &up->port.info->xmit;
+	struct ast_uart_dma_data *uart_dma_data = up->port.private_data;
+	
+	up->tx_done = 0;
+	DBG("line [%d], xmit->head =%d, xmit->tail = %d\n",up->port.line,xmit->head, xmit->tail);
+
+	if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
+		up->tx_count = 0;
+		up->tx_done = 1;
+		return;
+	}
+
+	if (up->port.x_char) {
+		serial_outp(up, UART_TX, up->port.x_char);
+		up->port.icount.tx++;
+		up->port.x_char = 0;
+		return;
+	}
+
+	up->tx_count = CIRC_CNT(xmit->head, xmit->tail, UART_XMIT_SIZE);
+
+	if (up->tx_count > (UART_XMIT_SIZE - xmit->tail)) {
+		up->tx_count = UART_XMIT_SIZE - xmit->tail;
+	}
+
+	if (up->tx_count > 4095) {
+		printk("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! TODO ....\n");
+		up->tx_count = 4095;
+	}
+
+	ast_uart_tx_dma_ctrl(uart_dma_data->chip_no, 
+					uart_dma_data->dma_ch, AST_UART_DMAOP_STOP);
+
+	ast_uart_tx_dma_enqueue(uart_dma_data->chip_no, 
+					uart_dma_data->dma_ch, up->dma_tx_addr, up->tx_count);
+
+	dma_sync_single_for_device(up->port.dev,
+				   up->dma_tx_addr,
+				   up->tx_count,
+				   DMA_TO_DEVICE);
+
+	ast_uart_tx_dma_ctrl(uart_dma_data->chip_no, 
+					uart_dma_data->dma_ch, AST_UART_DMAOP_TRIGGER);
+
+
+}
+
+static void ast_uart_tx_buffdone(struct ast1070_dma_ch *dma_ch, void *dev_id, u16 len)
+{
+	struct ast_uart_port *up = (struct ast_uart_port *) dev_id;
+	struct circ_buf *xmit = &up->port.info->xmit;
+
+	DBG("line [%d] : tx len = %d \n", up->port.line, len);	
+	
+	spin_lock(&up->port.lock);
+//TODO .....................................len ----> 
+	xmit->tail = (xmit->tail + up->tx_count) & (UART_XMIT_SIZE - 1);
+	up->port.icount.tx += up->tx_count;
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+			uart_write_wakeup(&up->port);
+
+	tasklet_schedule(&up->tx_tasklet);
+
+	spin_unlock(&up->port.lock);
+}
+
+static void ast_uart_rx_tasklet_func(unsigned long data)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port((struct uart_port *)data);
+	struct circ_buf *rx_ring = &up->rx_dma_buf;
+	struct tty_struct *tty = up->port.info->port.tty;
+	char flag;	
+	DBG("line [%d]\n",up->port.line);
+	DBG("rx_ring->head = %d, rx_ring->tail = %d , buff addr = %x \n",rx_ring->head, rx_ring->tail, rx_ring->buf);
+
+	spin_lock_irq(&up->lock);
+#if 1 	
+	DBG("\n rx data :  -- >");
+
+	while (rx_ring->head != rx_ring->tail) {
+		DBG("  %x ",rx_ring->buf[rx_ring->tail]);
+		flag = TTY_NORMAL;
+		uart_insert_char(&up->port, 0, UART_LSR_OE, \
+			rx_ring->buf[rx_ring->tail], flag);
+
+//		tty_insert_flip_string
+
+		rx_ring->tail++;
+		if (rx_ring->tail == up->dma_buf_size)
+			rx_ring->tail = 0;
+	}
+	DBG("\n");
+#else
+	
+	tty_insert_flip_string(tty, rx_ring->buf + rx_ring->tail, (rx_ring->head - rx_ring->tail));
+	rx_ring->tail = rx_ring->head;
+#endif
+	spin_unlock_irq(&up->lock);
+
+	spin_unlock(&up->port.lock);
+	tty_flip_buffer_push(tty);
+	spin_lock(&up->port.lock);
+
+
+}
+
+static void ast_uart_rx_buffdone(struct ast1070_dma_ch *dma_ch,
+				void *dev_id, u16 len)
+{
+	struct ast_uart_port *up = (struct ast_uart_port *)dev_id;
+//	struct tty_struct *tty = up->port.info->port.tty;
+	struct circ_buf *rx_ring = &up->rx_dma_buf;
+	struct ast_uart_dma_data *uart_dma_data = up->port.private_data;
+	u16 remain_size;
+
+	DBG("line [%d]\n",up->port.line);
+#if 0
+	int i;
+	printk("Buff virt addr = %x \n",rx_ring->buf);
+	for(i=0;i<len;i++)
+		printk("Buff [%x] \n", rx_ring->buf[up->rx_dma_buf.head + i]);
+#endif
+	DBG("head = %d, len : %d\n",up->rx_dma_buf.head, len);
+
+
+	//FOR NEXT ......
+	rx_ring->head += len;
+	
+	if (rx_ring->head == up->dma_buf_size) {
+		rx_ring->head = 0;
+	}
+
+	remain_size = up->dma_buf_size - rx_ring->head;
+
+	//Trigger Next RX dma
+	DBG("trigger next size = %d \n",remain_size);	
+	
+	ast_uart_rx_dma_ctrl(uart_dma_data->chip_no, 
+						uart_dma_data->dma_ch, AST_UART_DMAOP_STOP);
+
+	if(remain_size > DMA_BUFF_SIZE)
+		printk("Please check ---> \n");
+	
+	if(remain_size != 0)  {
+		ast_uart_rx_dma_enqueue(uart_dma_data->chip_no, 
+							uart_dma_data->dma_ch, up->dma_rx_addr + up->rx_dma_buf.head, remain_size);
+	} 
+	ast_uart_rx_dma_ctrl(uart_dma_data->chip_no, 
+						uart_dma_data->dma_ch, AST_UART_DMAOP_TRIGGER);
+
+	tasklet_schedule(&up->rx_tasklet);
+
+}
+
+/*
+ * FIFO support.
+ */
+static inline void serial8250_clear_fifos(struct ast_uart_port *p)
+{
+	serial_outp(p, UART_FCR, UART_FCR_ENABLE_FIFO);
+	serial_outp(p, UART_FCR, UART_FCR_ENABLE_FIFO |
+		       UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
+	serial_outp(p, UART_FCR, 0);
+}
+
+
+/*
+ * This routine is called by rs_init() to initialize a specific serial
+ * port.
+ */
+static void autoconfig(struct ast_uart_port *up, unsigned int probeflags)
+{
+	unsigned long flags;
+
+	if (!up->port.iobase && !up->port.mapbase && !up->port.membase)
+		return;
+
+	DEBUG_AUTOCONF("ttyDMA%d: autoconf (0x%04x, 0x%p): ",
+			up->port.line, up->port.iobase, up->port.membase);
+
+	spin_lock_irqsave(&up->port.lock, flags);
+
+	up->capabilities = 0;
+	up->bugs = 0;
+
+	up->port.type = PORT_16550A;
+	up->capabilities |= UART_CAP_FIFO;
+
+	up->port.fifosize = uart_config[up->port.type].fifo_size;
+	up->capabilities = uart_config[up->port.type].flags;
+	up->tx_loadsz = uart_config[up->port.type].tx_loadsz;
+
+	if (up->port.type == PORT_UNKNOWN)
+		goto out;
+
+	/*
+	 * Reset the UART.
+	 */
+	serial8250_clear_fifos(up);
+	serial_in(up, UART_RX);
+	serial_outp(up, UART_IER, 0);
+
+ out:
+	spin_unlock_irqrestore(&up->port.lock, flags);
+	DEBUG_AUTOCONF("type=%s\n", uart_config[up->port.type].name);
+}
+
+
+static inline void __stop_tx(struct ast_uart_port *p)
+{
+	if (p->ier & UART_IER_THRI) {
+		p->ier &= ~UART_IER_THRI;
+		serial_out(p, UART_IER, p->ier);
+	}
+}
+
+static void serial8250_stop_tx(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+
+	__stop_tx(up);
+
+}
+
+static void transmit_chars(struct ast_uart_port *up);
+
+static void serial8250_start_tx(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+
+	DBG("line [%d] -->  \n", port->line);
+	if (up->tx_done)
+		tasklet_schedule(&up->tx_tasklet);
+}
+
+static void serial8250_stop_rx(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+
+	DBG("line [%d] -->	\n", port->line);
+	up->ier &= ~UART_IER_RLSI;
+	up->port.read_status_mask &= ~UART_LSR_DR;
+	serial_out(up, UART_IER, up->ier);
+}
+
+static void serial8250_enable_ms(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+
+	up->ier |= UART_IER_MSI;
+	serial_out(up, UART_IER, up->ier);
+}
+
+static void transmit_chars(struct ast_uart_port *up)
+{
+	struct circ_buf *xmit = &up->port.info->xmit;
+	int count;
+
+	if (up->port.x_char) {
+		serial_outp(up, UART_TX, up->port.x_char);
+		up->port.icount.tx++;
+		up->port.x_char = 0;
+		return;
+	}
+	if (uart_tx_stopped(&up->port)) {
+		serial8250_stop_tx(&up->port);
+		return;
+	}
+	if (uart_circ_empty(xmit)) {
+		__stop_tx(up);
+		return;
+	}
+
+//	printk("uart_circ_chars_pending=%d\n",uart_circ_chars_pending(xmit));
+
+	count = up->tx_loadsz;
+	do {
+//printk("TX : buf = 0x%x\n", xmit->buf[xmit->tail]);
+		serial_out(up, UART_TX, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		up->port.icount.tx++;
+		if (uart_circ_empty(xmit))
+			break;
+	} while (--count > 0);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(&up->port);
+
+	DEBUG_INTR("THRE...");
+
+	if (uart_circ_empty(xmit))
+		__stop_tx(up);
+}
+
+static unsigned int check_modem_status(struct ast_uart_port *up)
+{
+	unsigned int status = serial_in(up, UART_MSR);
+
+	status |= up->msr_saved_flags;
+	up->msr_saved_flags = 0;
+	if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
+	    up->port.info != NULL) {
+		if (status & UART_MSR_TERI)
+			up->port.icount.rng++;
+		if (status & UART_MSR_DDSR)
+			up->port.icount.dsr++;
+		if (status & UART_MSR_DDCD)
+			uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
+		if (status & UART_MSR_DCTS)
+			uart_handle_cts_change(&up->port, status & UART_MSR_CTS);
+
+		wake_up_interruptible(&up->port.info->delta_msr_wait);
+	}
+
+	return status;
+}
+
+/*
+ * This handles the interrupt from one port.
+ */
+static inline void
+serial8250_handle_port(struct ast_uart_port *up)
+{
+	unsigned int status;
+	unsigned long flags;
+
+	spin_lock_irqsave(&up->port.lock, flags);
+	DEBUG_INTR("serial8250_handle_port \n");
+
+	status = serial_inp(up, UART_LSR);
+
+	DEBUG_INTR("status = %x...", status);
+
+	check_modem_status(up);
+	if (status & UART_LSR_THRE)
+		transmit_chars(up);
+
+	spin_unlock_irqrestore(&up->port.lock, flags);
+}
+
+/*
+ * This is the serial driver's interrupt routine.
+ */
+static irqreturn_t ast_uart_interrupt(int irq, void *dev_id)
+{
+	struct irq_info *i = dev_id;
+	int pass_counter = 0, handled = 0, end = 0;
+
+	DEBUG_INTR("ast_uart_interrupt(%d)...", irq);
+	spin_lock(&i->lock);
+
+	do {
+		struct ast_uart_port *up;
+		unsigned int iir;
+
+		up = (struct ast_uart_port *)(i->up);
+
+		iir = serial_in(up, UART_IIR);
+		DEBUG_INTR("iir %x \n", iir);
+		if (!(iir & UART_IIR_NO_INT)) {
+			printk("handle port \n");
+			serial8250_handle_port(up);
+			handled = 1;
+
+		}
+		else
+			end = 1;
+
+		if (pass_counter++ > PASS_LIMIT) {
+			/* If we hit this, we're dead. */
+			printk(KERN_ERR "ast-uart-dma: too much work for "
+				"irq%d\n", irq);
+			break;
+		}
+	} while (end);
+
+	spin_unlock(&i->lock);
+
+	DEBUG_INTR("end.\n");
+
+	return IRQ_RETVAL(handled);
+}
+
+static unsigned int serial8250_tx_empty(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	unsigned long flags;
+	unsigned int lsr;
+
+	spin_lock_irqsave(&up->port.lock, flags);
+	lsr = serial_in(up, UART_LSR);
+	up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+	spin_unlock_irqrestore(&up->port.lock, flags);
+
+	return lsr & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int serial8250_get_mctrl(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	unsigned int status;
+	unsigned int ret;
+
+	status = check_modem_status(up);
+
+	ret = 0;
+	if (status & UART_MSR_DCD)
+		ret |= TIOCM_CAR;
+	if (status & UART_MSR_RI)
+		ret |= TIOCM_RNG;
+	if (status & UART_MSR_DSR)
+		ret |= TIOCM_DSR;
+	if (status & UART_MSR_CTS)
+		ret |= TIOCM_CTS;
+	return ret;
+}
+
+static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	unsigned char mcr = 0;
+
+	if (mctrl & TIOCM_RTS)
+		mcr |= UART_MCR_RTS;
+	if (mctrl & TIOCM_DTR)
+		mcr |= UART_MCR_DTR;
+	if (mctrl & TIOCM_OUT1)
+		mcr |= UART_MCR_OUT1;
+	if (mctrl & TIOCM_OUT2)
+		mcr |= UART_MCR_OUT2;
+	if (mctrl & TIOCM_LOOP)
+		mcr |= UART_MCR_LOOP;
+
+	mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
+
+	serial_out(up, UART_MCR, mcr);
+}
+
+static void serial8250_break_ctl(struct uart_port *port, int break_state)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	unsigned long flags;
+
+	spin_lock_irqsave(&up->port.lock, flags);
+	if (break_state == -1)
+		up->lcr |= UART_LCR_SBC;
+	else
+		up->lcr &= ~UART_LCR_SBC;
+	serial_out(up, UART_LCR, up->lcr);
+	spin_unlock_irqrestore(&up->port.lock, flags);
+}
+
+static int serial8250_startup(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	//TX DMA 
+	struct circ_buf *xmit = &port->info->xmit;
+	struct ast_uart_dma_data *uart_dma_data = up->port.private_data;
+	unsigned long flags;
+	unsigned char lsr, iir;
+	int retval;
+	int irq_flags = up->port.flags & UPF_SHARE_IRQ ? IRQF_SHARED : 0;
+
+	DBG("line [%d] \n",port->line);
+	
+	up->capabilities = uart_config[up->port.type].flags;
+	up->mcr = 0;
+	
+	/*
+	 * Clear the FIFO buffers and disable them.
+	 * (they will be reenabled in set_termios())
+	 */
+	serial8250_clear_fifos(up);
+
+	/*
+	 * Clear the interrupt registers.
+	 */
+	(void) serial_inp(up, UART_LSR);
+	(void) serial_inp(up, UART_RX);
+	(void) serial_inp(up, UART_IIR);
+	(void) serial_inp(up, UART_MSR);
+
+	ast_uart_irq[0].up = up;
+	retval = request_irq(up->port.irq, ast_uart_interrupt,
+				 irq_flags, "ast-uart-dma", ast_uart_irq);
+	if (retval)
+		return retval;
+
+	/*
+	 * Now, initialize the UART
+	 */
+	serial_outp(up, UART_LCR, UART_LCR_WLEN8);
+
+	spin_lock_irqsave(&up->port.lock, flags);
+	up->port.mctrl |= TIOCM_OUT2;
+
+	serial8250_set_mctrl(&up->port, up->port.mctrl);
+
+	/*
+	 * Do a quick test to see if we receive an
+	 * interrupt when we enable the TX irq.
+	 */
+	serial_outp(up, UART_IER, UART_IER_THRI);
+	lsr = serial_in(up, UART_LSR);
+	iir = serial_in(up, UART_IIR);
+	serial_outp(up, UART_IER, 0);
+
+	if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
+		if (!(up->bugs & UART_BUG_TXEN)) {
+			up->bugs |= UART_BUG_TXEN;
+			printk("ttyDMA%d - enabling bad tx status \n",
+				 port->line);
+		}
+	} else {
+		up->bugs &= ~UART_BUG_TXEN;
+	}
+
+	spin_unlock_irqrestore(&up->port.lock, flags);
+
+	/*
+	 * Clear the interrupt registers again for luck, and clear the
+	 * saved flags to avoid getting false values from polling
+	 * routines or the previous session.
+	 */
+	serial_inp(up, UART_LSR);
+	serial_inp(up, UART_RX);
+	serial_inp(up, UART_IIR);
+	serial_inp(up, UART_MSR);
+	up->lsr_saved_flags = 0;
+	up->msr_saved_flags = 0;
+
+	//RX DMA
+	up->rx_dma_buf.head = 0;
+	up->rx_dma_buf.tail = 0;
+	up->dma_buf_size = 2048;//DMA_BUFF_SIZE -1;	//4096  is dma size  please check
+#if 0	
+	up->dma_rx_addr = dma_map_single(port->dev,
+					   up->rx_dma_buf.buf,
+					   up->dma_buf_size,
+					   DMA_FROM_DEVICE);
+#else	
+	up->rx_dma_buf.buf = (unsigned char *)dma_alloc_coherent(NULL, 
+								up->dma_buf_size, &up->dma_rx_addr, GFP_KERNEL);
+#endif
+	DBG("RX buff vir = %x, phy = %x \n", up->rx_dma_buf.buf, up->dma_rx_addr);
+
+	ast_uart_rx_dma_ctrl(uart_dma_data->chip_no, uart_dma_data->dma_ch, AST_UART_DMAOP_STOP);
+
+	ast_uart_rx_dma_enqueue(uart_dma_data->chip_no, uart_dma_data->dma_ch, up->dma_rx_addr, up->dma_buf_size);
+	
+	up->rx_tasklet_done = 1;
+	ast_uart_rx_dma_ctrl(uart_dma_data->chip_no, uart_dma_data->dma_ch, AST_UART_DMAOP_TRIGGER);
+
+	up->tx_dma_buf.head = 0;
+	up->tx_dma_buf.buf = xmit->buf;
+	up->dma_tx_addr = dma_map_single(port->dev,
+				       up->tx_dma_buf.buf,
+				       UART_XMIT_SIZE,
+				       DMA_TO_DEVICE);
+	up->tx_done = 1;
+	up->tx_count = 0;
+
+	return 0;
+}
+
+static void serial8250_shutdown(struct uart_port *port)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	struct ast_uart_dma_data *uart_dma_data = up->port.private_data;
+	unsigned long flags;
+	//int i;
+	DBG("line [%d]\n",port->line);	
+	/*
+	 * Disable interrupts from this port
+	 */
+#if 0
+	for(i=0; i<100; i++) {
+		printk("tx_count_table[%d] = %d\n", i, tx_count_table[i]);
+	}
+#endif
+	
+	up->ier = 0;
+	serial_outp(up, UART_IER, 0);
+
+	spin_lock_irqsave(&up->port.lock, flags);
+	up->port.mctrl &= ~TIOCM_OUT2;
+
+	serial8250_set_mctrl(&up->port, up->port.mctrl);
+	spin_unlock_irqrestore(&up->port.lock, flags);
+
+	/*
+	 * Disable break condition and FIFOs
+	 */
+	serial_out(up, UART_LCR, serial_inp(up, UART_LCR) & ~UART_LCR_SBC);
+	serial8250_clear_fifos(up);
+
+	(void) serial_in(up, UART_RX);
+	
+	ast_uart_rx_dma_ctrl(uart_dma_data->chip_no, uart_dma_data->dma_ch, AST_UART_DMAOP_STOP);
+
+	ast_uart_tx_dma_ctrl(uart_dma_data->chip_no, uart_dma_data->dma_ch, AST_UART_DMAOP_STOP);
+	//TODO .... Free ---- dma 	
+	DBG("free TX , RX buffer \n");
+#if 1	
+	dma_unmap_single(port->dev, up->dma_rx_addr,
+			 up->dma_buf_size,
+			 DMA_FROM_DEVICE);
+#else
+	dma_free_coherent(port->dev, up->dma_buf_size, 
+			up->rx_dma_buf.buf, up->dma_rx_addr);
+#endif
+
+	dma_unmap_single(port->dev, up->dma_tx_addr,
+			 UART_XMIT_SIZE,
+			 DMA_TO_DEVICE);
+
+
+	free_irq(up->port.irq, ast_uart_irq);
+
+}
+
+static unsigned int serial8250_get_divisor(struct uart_port *port, unsigned int baud)
+{
+	unsigned int quot;
+
+	quot = uart_get_divisor(port, baud);
+
+	return quot;
+}
+
+static void
+serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
+		       struct ktermios *old)
+{
+	struct ast_uart_port *up = to_ast_dma_uart_port(port);
+	unsigned char cval, fcr = 0;
+	unsigned long flags;
+	unsigned int baud, quot;
+
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		cval = UART_LCR_WLEN5;
+		break;
+	case CS6:
+		cval = UART_LCR_WLEN6;
+		break;
+	case CS7:
+		cval = UART_LCR_WLEN7;
+		break;
+	default:
+	case CS8:
+		cval = UART_LCR_WLEN8;
+		break;
+	}
+
+	if (termios->c_cflag & CSTOPB)
+		cval |= UART_LCR_STOP;
+	if (termios->c_cflag & PARENB)
+		cval |= UART_LCR_PARITY;
+	if (!(termios->c_cflag & PARODD))
+		cval |= UART_LCR_EPAR;
+#ifdef CMSPAR
+	if (termios->c_cflag & CMSPAR)
+		cval |= UART_LCR_SPAR;
+#endif
+
+	/*
+	 * Ask the core to calculate the divisor for us.
+	 */
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+	quot = serial8250_get_divisor(port, baud);
+
+	if (up->capabilities & UART_CAP_FIFO && up->port.fifosize > 1) {
+		if (baud < 2400)
+			fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
+		else
+			fcr = uart_config[up->port.type].fcr;
+	}
+
+	/*
+	 * Ok, we're now changing the port state.  Do it with
+	 * interrupts disabled.
+	 */
+	spin_lock_irqsave(&up->port.lock, flags);
+
+	/*
+	 * Update the per-port timeout.
+	 */
+	uart_update_timeout(port, termios->c_cflag, baud);
+
+	up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
+	if (termios->c_iflag & INPCK)
+		up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
+	if (termios->c_iflag & (BRKINT | PARMRK))
+		up->port.read_status_mask |= UART_LSR_BI;
+
+	/*
+	 * Characteres to ignore
+	 */
+	up->port.ignore_status_mask = 0;
+	if (termios->c_iflag & IGNPAR)
+		up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
+	if (termios->c_iflag & IGNBRK) {
+		up->port.ignore_status_mask |= UART_LSR_BI;
+		/*
+		 * If we're ignoring parity and break indicators,
+		 * ignore overruns too (for real raw support).
+		 */
+		if (termios->c_iflag & IGNPAR)
+			up->port.ignore_status_mask |= UART_LSR_OE;
+	}
+
+	/*
+	 * ignore all characters if CREAD is not set
+	 */
+	if ((termios->c_cflag & CREAD) == 0)
+		up->port.ignore_status_mask |= UART_LSR_DR;
+
+	/*
+	 * CTS flow control flag and modem status interrupts
+	 */
+	up->ier &= ~UART_IER_MSI;
+	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
+		up->ier |= UART_IER_MSI;
+
+	serial_out(up, UART_IER, up->ier);
+
+
+	serial_outp(up, UART_LCR, cval | UART_LCR_DLAB);/* set DLAB */
+
+	serial_dl_write(up, quot);
+
+	/*
+	 * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
+	 * is written without DLAB set, this mode will be disabled.
+	 */
+
+	serial_outp(up, UART_LCR, cval);		/* reset DLAB */
+	up->lcr = cval;					/* Save LCR */
+		if (fcr & UART_FCR_ENABLE_FIFO) {
+			/* emulated UARTs (Lucent Venus 167x) need two steps */
+			serial_outp(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+		}
+		serial_outp(up, UART_FCR, fcr);		/* set fcr */
+	serial8250_set_mctrl(&up->port, up->port.mctrl);
+	spin_unlock_irqrestore(&up->port.lock, flags);
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+}
+
+static void
+serial8250_pm(struct uart_port *port, unsigned int state,
+	      unsigned int oldstate)
+{
+	struct ast_uart_port *p = (struct ast_uart_port *)port;
+
+	if (p->pm)
+		p->pm(port, state, oldstate);
+}
+
+/*
+ * Resource handling.
+ */
+static int serial8250_request_std_resource(struct ast_uart_port *up)
+{
+	unsigned int size = 8 << up->port.regshift;
+	int ret = 0;
+
+		if (!up->port.mapbase)
+			return ret;
+
+		if (!request_mem_region(up->port.mapbase, size, "ast-uart-dma")) {
+			ret = -EBUSY;
+			return ret;
+		}
+
+		if (up->port.flags & UPF_IOREMAP) {
+			up->port.membase = ioremap_nocache(up->port.mapbase,
+									size);
+			if (!up->port.membase) {
+				release_mem_region(up->port.mapbase, size);
+				ret = -ENOMEM;
+				return ret;
+			}
+		}
+	return ret;
+}
+
+static void serial8250_release_std_resource(struct ast_uart_port *up)
+{
+	unsigned int size = 8 << up->port.regshift;
+
+		if (!up->port.mapbase)
+			return;
+
+		if (up->port.flags & UPF_IOREMAP) {
+			iounmap(up->port.membase);
+			up->port.membase = NULL;
+		}
+
+		release_mem_region(up->port.mapbase, size);
+}
+
+
+static void serial8250_release_port(struct uart_port *port)
+{
+	struct ast_uart_port *up = (struct ast_uart_port *)port;
+
+	serial8250_release_std_resource(up);
+}
+
+static int serial8250_request_port(struct uart_port *port)
+{
+	struct ast_uart_port *up = (struct ast_uart_port *)port;
+	int ret = 0;
+
+	ret = serial8250_request_std_resource(up);
+	if (ret == 0 )
+			serial8250_release_std_resource(up);
+
+	return ret;
+}
+
+static void serial8250_config_port(struct uart_port *port, int flags)
+{
+	struct ast_uart_port *up = (struct ast_uart_port *)port;
+	int probeflags = PROBE_ANY;
+	int ret;
+
+	/*
+	 * Find the region that we can probe for.  This in turn
+	 * tells us whether we can probe for the type of port.
+	 */
+	ret = serial8250_request_std_resource(up);
+	if (ret < 0)
+		return;
+
+	if (flags & UART_CONFIG_TYPE)
+		autoconfig(up, probeflags);
+
+	if (up->port.type == PORT_UNKNOWN)
+		serial8250_release_std_resource(up);
+}
+
+static int
+serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+	return 0;
+}
+
+static const char *
+serial8250_type(struct uart_port *port)
+{
+	int type = port->type;
+
+	if (type >= ARRAY_SIZE(uart_config))
+		type = 0;
+	return uart_config[type].name;
+}
+
+static struct uart_ops serial8250_pops = {
+	.tx_empty	= serial8250_tx_empty,
+	.set_mctrl	= serial8250_set_mctrl,
+	.get_mctrl	= serial8250_get_mctrl,
+	.stop_tx	= serial8250_stop_tx,
+	.start_tx	= serial8250_start_tx,
+	.stop_rx	= serial8250_stop_rx,
+	.enable_ms	= serial8250_enable_ms,
+	.break_ctl	= serial8250_break_ctl,
+	.startup	= serial8250_startup,
+	.shutdown	= serial8250_shutdown,
+	.set_termios	= serial8250_set_termios,
+	.pm		= serial8250_pm,
+	.type		= serial8250_type,
+	.release_port	= serial8250_release_port,
+	.request_port	= serial8250_request_port,
+	.config_port	= serial8250_config_port,
+	.verify_port	= serial8250_verify_port,
+};
+
+static void __init serial8250_isa_init_ports(void)
+{
+	static int first = 1;
+	int i;
+
+	if (!first)
+		return;
+	first = 0;
+
+	for (i = 0; i < nr_uarts; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+
+		up->port.line = i;
+		spin_lock_init(&up->port.lock);
+
+		/*
+		 * ALPHA_KLUDGE_MCR needs to be killed.
+		 */
+		up->mcr_mask = ~ALPHA_KLUDGE_MCR;
+		up->mcr_force = ALPHA_KLUDGE_MCR;
+
+		up->port.ops = &serial8250_pops;
+	}
+
+}
+
+static void __init
+serial8250_register_ports(struct uart_driver *drv, struct device *dev)
+{
+	int i;
+	printk("serial8250_register_ports \n");
+
+	serial8250_isa_init_ports();
+
+	for (i = 0; i < nr_uarts; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+		up->port.dev = dev;
+		uart_add_one_port(drv, &up->port);
+	}
+}
+
+#define SERIAL8250_CONSOLE	NULL
+
+static struct uart_driver serial8250_reg = {
+	.owner			= THIS_MODULE,
+	.driver_name		= "ast-uart-dma",
+	.dev_name		= "ttyDMA",
+#if 0
+	.major			= TTY_MAJOR,
+	.minor			= 64,
+#else
+	.major			= 204, // like atmel_serial
+	.minor			= 155,
+#endif
+	.nr			= UART_DMA_NR,
+	.cons			= SERIAL8250_CONSOLE,
+};
+
+
+#if 0
+/**
+ *	serial8250_suspend_port - suspend one serial port
+ *	@line:  serial line number
+ *
+ *	Suspend one serial port.
+ */
+void serial8250_suspend_port(int line)
+{
+	uart_suspend_port(&serial8250_reg, &ast_uart_ports[line].port);
+}
+
+/**
+ *	serial8250_resume_port - resume one serial port
+ *	@line:  serial line number
+ *
+ *	Resume one serial port.
+ */
+void serial8250_resume_port(int line)
+{
+	struct ast_uart_port *up = &ast_uart_ports[line];
+
+	uart_resume_port(&serial8250_reg, &up->port);
+}
+#endif
+
+/*
+ * Register a set of serial devices attached to a platform device.  The
+ * list is terminated with a zero flags entry, which means we expect
+ * all entries to have at least UPF_BOOT_AUTOCONF set.
+ */
+static int __devinit serial8250_probe(struct platform_device *dev)
+{
+	struct plat_serial8250_port *p = dev->dev.platform_data;
+	struct uart_port port;
+	struct ast_uart_dma_data *uart_dma_data;
+	int ret, i;
+
+	if(UART_XMIT_SIZE > DMA_BUFF_SIZE)
+		printk("UART_XMIT_SIZE > DMA_BUFF_SIZE : Please Check \n");
+	
+	memset(&port, 0, sizeof(struct uart_port));
+
+	for (i = 0; p && p->flags != 0; p++, i++) {
+		port.iobase		= p->iobase;
+		port.membase		= p->membase;
+		port.irq		= p->irq;
+		port.uartclk		= p->uartclk;
+		port.regshift		= p->regshift;
+		port.iotype		= p->iotype;
+		port.flags		= p->flags;
+		port.mapbase		= p->mapbase;
+		port.hub6		= p->hub6;
+		port.private_data	= p->private_data;
+		port.dev		= &dev->dev;
+		uart_dma_data = p->private_data;
+		if (share_irqs)
+			port.flags |= UPF_SHARE_IRQ;
+		ret = ast_uart_register_port(&port);
+		if (ret < 0) {
+			dev_err(&dev->dev, "unable to register port at index %d "
+				"(IO%lx MEM%llx IRQ%d): %d\n", i,
+				p->iobase, (unsigned long long)p->mapbase,
+				p->irq, ret);
+		}
+//		printk("TODO ...... line = %d \n",i);
+		ret = ast_uart_rx_dma_request(uart_dma_data->chip_no, uart_dma_data->dma_ch, ast_uart_rx_buffdone, &ast_uart_ports[i]);
+		if (ret < 0) {
+			printk("Error : failed to get rx dma channel[%d]\n", uart_dma_data->dma_ch);
+			goto out_ast_uart_unregister_port;
+		}
+
+		ret = ast_uart_tx_dma_request(uart_dma_data->chip_no, uart_dma_data->dma_ch, ast_uart_tx_buffdone, &ast_uart_ports[i]);
+		if (ret < 0) {
+			printk("Error : failed to get tx dma channel[%d]\n", uart_dma_data->dma_ch);
+			return ret;
+		}
+	}
+
+	return 0;
+	
+out_ast_uart_unregister_port:
+	for (i = 0; i < nr_uarts; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+
+		if (up->port.dev == &dev->dev)
+			ast_uart_unregister_port(i);
+	};
+	return ret;
+
+}
+
+/*
+ * Remove serial ports registered against a platform device.
+ */
+static int __devexit serial8250_remove(struct platform_device *dev)
+{
+	int i;
+
+	for (i = 0; i < nr_uarts; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+
+		if (up->port.dev == &dev->dev)
+			ast_uart_unregister_port(i);
+	}
+	//TODO ..
+//	pl080_dma_free(uart_dma_rx.channel, (void *)uart_dma_rx.client);
+//	pl080_dma_free(uart_dma_tx.channel, (void *)uart_dma_tx.client);
+	
+	return 0;
+}
+
+static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
+{
+	int i;
+
+	for (i = 0; i < UART_DMA_NR; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+
+		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
+			uart_suspend_port(&serial8250_reg, &up->port);
+	}
+
+	return 0;
+}
+
+static int serial8250_resume(struct platform_device *dev)
+{
+	int i;
+
+	for (i = 0; i < UART_DMA_NR; i++) {
+		struct ast_uart_port *up = &ast_uart_ports[i];
+
+		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
+			serial8250_resume_port(i);
+	}
+
+	return 0;
+}
+
+static struct platform_driver serial8250_ast_dma_driver = {
+	.probe		= serial8250_probe,
+	.remove		= __devexit_p(serial8250_remove),
+	.suspend	= serial8250_suspend,
+	.resume		= serial8250_resume,
+	.driver		= {
+		.name	= "ast-uart-dma",
+		.owner	= THIS_MODULE,
+	},
+};
+
+/*
+ * This "device" covers _all_ ISA 8250-compatible serial devices listed
+ * in the table in include/asm/serial.h
+ */
+static struct platform_device *serial8250_isa_devs;
+
+/*
+ * serial8250_register_port and serial8250_unregister_port allows for
+ * 16x50 serial ports to be configured at run-time, to support PCMCIA
+ * modems and PCI multiport cards.
+ */
+
+static struct ast_uart_port *serial8250_find_match_or_unused(struct uart_port *port)
+{
+	int i;
+
+	/*
+	 * First, find a port entry which matches.
+	 */
+	for (i = 0; i < nr_uarts; i++)
+		if (uart_match_port(&ast_uart_ports[i].port, port))
+			return &ast_uart_ports[i];
+
+	/*
+	 * We didn't find a matching entry, so look for the first
+	 * free entry.  We look for one which hasn't been previously
+	 * used (indicated by zero iobase).
+	 */
+	for (i = 0; i < nr_uarts; i++)
+		if (ast_uart_ports[i].port.type == PORT_UNKNOWN &&
+		    ast_uart_ports[i].port.iobase == 0)
+			return &ast_uart_ports[i];
+
+	/*
+	 * That also failed.  Last resort is to find any entry which
+	 * doesn't have a real port associated with it.
+	 */
+	for (i = 0; i < nr_uarts; i++)
+		if (ast_uart_ports[i].port.type == PORT_UNKNOWN)
+			return &ast_uart_ports[i];
+
+	return NULL;
+}
+
+/**
+ *	serial8250_register_port - register a serial port
+ *	@port: serial port template
+ *
+ *	Configure the serial port specified by the request. If the
+ *	port exists and is in use, it is hung up and unregistered
+ *	first.
+ *
+ *	The port is then probed and if necessary the IRQ is autodetected
+ *	If this fails an error is returned.
+ *
+ *	On success the port is ready to use and the line number is returned.
+ */
+int ast_uart_register_port(struct uart_port *port)
+{
+	struct ast_uart_port *uart;
+	int ret = -ENOSPC;
+
+	if (port->uartclk == 0)
+		return -EINVAL;
+printk("register port line %d\n",port->line);
+	mutex_lock(&ast_uart_mutex);
+
+	uart = serial8250_find_match_or_unused(port);
+	if (uart) {
+		uart_remove_one_port(&serial8250_reg, &uart->port);
+
+		uart->port.iobase       = port->iobase;
+		uart->port.membase      = port->membase;
+		uart->port.irq          = port->irq;
+		uart->port.uartclk      = port->uartclk;
+		uart->port.fifosize     = port->fifosize;
+		uart->port.regshift     = port->regshift;
+		uart->port.iotype       = port->iotype;
+		uart->port.flags        = port->flags | UPF_BOOT_AUTOCONF;
+		uart->port.mapbase      = port->mapbase;
+		uart->port.private_data = port->private_data;
+		if (port->dev)
+			uart->port.dev = port->dev;
+
+		ret = uart_add_one_port(&serial8250_reg, &uart->port);
+		if (ret == 0)
+			ret = uart->port.line;
+
+		spin_lock_init(&uart->lock);
+
+		tasklet_init(&uart->rx_tasklet, ast_uart_rx_tasklet_func,
+				(unsigned long)uart);
+	
+		tasklet_init(&uart->tx_tasklet, ast_uart_tx_tasklet_func,
+				(unsigned long)uart);
+
+	}
+
+	mutex_unlock(&ast_uart_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(ast_uart_register_port);
+
+/**
+ *	serial8250_unregister_port - remove a 16x50 serial port at runtime
+ *	@line: serial line number
+ *
+ *	Remove one serial port.  This may not be called from interrupt
+ *	context.  We hand the port back to the our control.
+ */
+void ast_uart_unregister_port(int line)
+{
+	struct ast_uart_port *uart = &ast_uart_ports[line];
+
+	mutex_lock(&ast_uart_mutex);
+	uart_remove_one_port(&serial8250_reg, &uart->port);
+	if (serial8250_isa_devs) {
+		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
+		uart->port.type = PORT_UNKNOWN;
+		uart->port.dev = &serial8250_isa_devs->dev;
+		uart_add_one_port(&serial8250_reg, &uart->port);
+	} else {
+		uart->port.dev = NULL;
+	}
+	mutex_unlock(&ast_uart_mutex);
+}
+EXPORT_SYMBOL(ast_uart_unregister_port);
+
+static int __init ast_uart_init(void)
+{
+	int ret;
+
+	if (nr_uarts > UART_DMA_NR)
+		nr_uarts = UART_DMA_NR;
+
+	printk(KERN_INFO "ast-uart-dma: UART driver with DMA "
+		"%d ports, IRQ sharing %sabled\n", nr_uarts,
+		share_irqs ? "en" : "dis");
+
+		spin_lock_init(&ast_uart_irq[0].lock);
+
+	ret = uart_register_driver(&serial8250_reg);
+	if (ret)
+		goto out;
+
+	serial8250_isa_devs = platform_device_alloc("ast-uart-dma",
+						    PLAT8250_DEV_LEGACY);
+	if (!serial8250_isa_devs) {
+		ret = -ENOMEM;
+		goto unreg_uart_drv;
+	}
+
+	ret = platform_device_add(serial8250_isa_devs);
+	if (ret)
+		goto put_dev;
+
+	serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
+
+	ret = platform_driver_register(&serial8250_ast_dma_driver);
+	if (ret == 0)
+		goto out;
+
+	platform_device_del(serial8250_isa_devs);
+ put_dev:
+	platform_device_put(serial8250_isa_devs);
+ unreg_uart_drv:
+	uart_unregister_driver(&serial8250_reg);
+ out:
+	return ret;
+}
+
+static void __exit ast_uart_exit(void)
+{
+	struct platform_device *isa_dev = serial8250_isa_devs;
+
+	/*
+	 * This tells serial8250_unregister_port() not to re-register
+	 * the ports (thereby making serial8250_ast_dma_driver permanently
+	 * in use.)
+	 */
+	serial8250_isa_devs = NULL;
+
+	platform_driver_unregister(&serial8250_ast_dma_driver);
+	platform_device_unregister(isa_dev);
+
+	uart_unregister_driver(&serial8250_reg);
+}
+
+late_initcall(ast_uart_init);
+module_exit(ast_uart_exit);
+
+#if 0
+EXPORT_SYMBOL(serial8250_suspend_port);
+EXPORT_SYMBOL(serial8250_resume_port);
+#endif
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("AST DMA serial driver");
+MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);