Serial: EG20T: add PCH_UART driver

UART driver of Intel EG20T(Topcliff) PCH

Intel EG20T PCH is the platform controller hub that is going to be used in
Intel's general embedded platform. All IO peripherals in
Intel EG20T PCH are actually devices sitting on AMBA bus.
Intel EG20T PCH has UART I/F. Using this I/F, it is able to access system
devices connected to UART.

Signed-off-by: Tomoya MORINAGA <tomoya-linux@dsn.okisemi.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 1459 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 9f6daae5edf2..fa02904c1910 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -1648,4 +1648,12 @@ config SERIAL_IFX6X60
 	help
 	  Support for the IFX6x60 modem devices on Intel MID platforms.
 
+config SERIAL_PCH_UART
+	tristate "Intel EG20T PCH UART"
+	select SERIAL_CORE
+	depends on PCI
+	help
+	  This driver is for PCH(Platform controller Hub) UART of Intel EG20T
+	  which is an IOH(Input/Output Hub) for x86 embedded processor.
+	  Enabling PCH_DMA, this PCH UART works as DMA mode.
 endmenu
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index a5e2264b2a80..f9b26dfb175d 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -91,3 +91,4 @@ obj-$(CONFIG_SERIAL_MRST_MAX3110)	+= mrst_max3110.o
 obj-$(CONFIG_SERIAL_MFD_HSU)	+= mfd.o
 obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o
 obj-$(CONFIG_SERIAL_IFX6X60)  	+= ifx6x60.o
+obj-$(CONFIG_SERIAL_PCH_UART)	+= pch_uart.o
diff --git a/drivers/serial/pch_uart.c b/drivers/serial/pch_uart.c
new file mode 100644
index 000000000000..b94d1fa76973
--- /dev/null
+++ b/drivers/serial/pch_uart.c
@@ -0,0 +1,1450 @@
+/*
+ *Copyright (C) 2010 OKI SEMICONDUCTOR CO., 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; version 2 of the License.
+ *
+ *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/serial_reg.h>
+#include <linux/pci.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/serial_core.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+
+#include <linux/dmaengine.h>
+#include <linux/pch_dma.h>
+
+enum {
+	PCH_UART_HANDLED_RX_INT_SHIFT,
+	PCH_UART_HANDLED_TX_INT_SHIFT,
+	PCH_UART_HANDLED_RX_ERR_INT_SHIFT,
+	PCH_UART_HANDLED_RX_TRG_INT_SHIFT,
+	PCH_UART_HANDLED_MS_INT_SHIFT,
+};
+
+enum {
+	PCH_UART_8LINE,
+	PCH_UART_2LINE,
+};
+
+#define PCH_UART_DRIVER_DEVICE "ttyPCH"
+
+#define PCH_UART_NR_GE_256FIFO		1
+#define PCH_UART_NR_GE_64FIFO		3
+#define PCH_UART_NR_GE	(PCH_UART_NR_GE_256FIFO+PCH_UART_NR_GE_64FIFO)
+#define PCH_UART_NR	PCH_UART_NR_GE
+
+#define PCH_UART_HANDLED_RX_INT	(1<<((PCH_UART_HANDLED_RX_INT_SHIFT)<<1))
+#define PCH_UART_HANDLED_TX_INT	(1<<((PCH_UART_HANDLED_TX_INT_SHIFT)<<1))
+#define PCH_UART_HANDLED_RX_ERR_INT	(1<<((\
+					PCH_UART_HANDLED_RX_ERR_INT_SHIFT)<<1))
+#define PCH_UART_HANDLED_RX_TRG_INT	(1<<((\
+					PCH_UART_HANDLED_RX_TRG_INT_SHIFT)<<1))
+#define PCH_UART_HANDLED_MS_INT	(1<<((PCH_UART_HANDLED_MS_INT_SHIFT)<<1))
+
+#define PCH_UART_RBR		0x00
+#define PCH_UART_THR		0x00
+
+#define PCH_UART_IER_MASK	(PCH_UART_IER_ERBFI|PCH_UART_IER_ETBEI|\
+				PCH_UART_IER_ELSI|PCH_UART_IER_EDSSI)
+#define PCH_UART_IER_ERBFI	0x00000001
+#define PCH_UART_IER_ETBEI	0x00000002
+#define PCH_UART_IER_ELSI	0x00000004
+#define PCH_UART_IER_EDSSI	0x00000008
+
+#define PCH_UART_IIR_IP			0x00000001
+#define PCH_UART_IIR_IID		0x00000006
+#define PCH_UART_IIR_MSI		0x00000000
+#define PCH_UART_IIR_TRI		0x00000002
+#define PCH_UART_IIR_RRI		0x00000004
+#define PCH_UART_IIR_REI		0x00000006
+#define PCH_UART_IIR_TOI		0x00000008
+#define PCH_UART_IIR_FIFO256		0x00000020
+#define PCH_UART_IIR_FIFO64		PCH_UART_IIR_FIFO256
+#define PCH_UART_IIR_FE			0x000000C0
+
+#define PCH_UART_FCR_FIFOE		0x00000001
+#define PCH_UART_FCR_RFR		0x00000002
+#define PCH_UART_FCR_TFR		0x00000004
+#define PCH_UART_FCR_DMS		0x00000008
+#define PCH_UART_FCR_FIFO256		0x00000020
+#define PCH_UART_FCR_RFTL		0x000000C0
+
+#define PCH_UART_FCR_RFTL1		0x00000000
+#define PCH_UART_FCR_RFTL64		0x00000040
+#define PCH_UART_FCR_RFTL128		0x00000080
+#define PCH_UART_FCR_RFTL224		0x000000C0
+#define PCH_UART_FCR_RFTL16		PCH_UART_FCR_RFTL64
+#define PCH_UART_FCR_RFTL32		PCH_UART_FCR_RFTL128
+#define PCH_UART_FCR_RFTL56		PCH_UART_FCR_RFTL224
+#define PCH_UART_FCR_RFTL4		PCH_UART_FCR_RFTL64
+#define PCH_UART_FCR_RFTL8		PCH_UART_FCR_RFTL128
+#define PCH_UART_FCR_RFTL14		PCH_UART_FCR_RFTL224
+#define PCH_UART_FCR_RFTL_SHIFT		6
+
+#define PCH_UART_LCR_WLS	0x00000003
+#define PCH_UART_LCR_STB	0x00000004
+#define PCH_UART_LCR_PEN	0x00000008
+#define PCH_UART_LCR_EPS	0x00000010
+#define PCH_UART_LCR_SP		0x00000020
+#define PCH_UART_LCR_SB		0x00000040
+#define PCH_UART_LCR_DLAB	0x00000080
+#define PCH_UART_LCR_NP		0x00000000
+#define PCH_UART_LCR_OP		PCH_UART_LCR_PEN
+#define PCH_UART_LCR_EP		(PCH_UART_LCR_PEN | PCH_UART_LCR_EPS)
+#define PCH_UART_LCR_1P		(PCH_UART_LCR_PEN | PCH_UART_LCR_SP)
+#define PCH_UART_LCR_0P		(PCH_UART_LCR_PEN | PCH_UART_LCR_EPS |\
+				PCH_UART_LCR_SP)
+
+#define PCH_UART_LCR_5BIT	0x00000000
+#define PCH_UART_LCR_6BIT	0x00000001
+#define PCH_UART_LCR_7BIT	0x00000002
+#define PCH_UART_LCR_8BIT	0x00000003
+
+#define PCH_UART_MCR_DTR	0x00000001
+#define PCH_UART_MCR_RTS	0x00000002
+#define PCH_UART_MCR_OUT	0x0000000C
+#define PCH_UART_MCR_LOOP	0x00000010
+#define PCH_UART_MCR_AFE	0x00000020
+
+#define PCH_UART_LSR_DR		0x00000001
+#define PCH_UART_LSR_ERR	(1<<7)
+
+#define PCH_UART_MSR_DCTS	0x00000001
+#define PCH_UART_MSR_DDSR	0x00000002
+#define PCH_UART_MSR_TERI	0x00000004
+#define PCH_UART_MSR_DDCD	0x00000008
+#define PCH_UART_MSR_CTS	0x00000010
+#define PCH_UART_MSR_DSR	0x00000020
+#define PCH_UART_MSR_RI		0x00000040
+#define PCH_UART_MSR_DCD	0x00000080
+#define PCH_UART_MSR_DELTA	(PCH_UART_MSR_DCTS | PCH_UART_MSR_DDSR |\
+				PCH_UART_MSR_TERI | PCH_UART_MSR_DDCD)
+
+#define PCH_UART_DLL		0x00
+#define PCH_UART_DLM		0x01
+
+#define DIV_ROUND(a, b)	(((a) + ((b)/2)) / (b))
+
+#define PCH_UART_IID_RLS	(PCH_UART_IIR_REI)
+#define PCH_UART_IID_RDR	(PCH_UART_IIR_RRI)
+#define PCH_UART_IID_RDR_TO	(PCH_UART_IIR_RRI | PCH_UART_IIR_TOI)
+#define PCH_UART_IID_THRE	(PCH_UART_IIR_TRI)
+#define PCH_UART_IID_MS		(PCH_UART_IIR_MSI)
+
+#define PCH_UART_HAL_PARITY_NONE	(PCH_UART_LCR_NP)
+#define PCH_UART_HAL_PARITY_ODD		(PCH_UART_LCR_OP)
+#define PCH_UART_HAL_PARITY_EVEN	(PCH_UART_LCR_EP)
+#define PCH_UART_HAL_PARITY_FIX1	(PCH_UART_LCR_1P)
+#define PCH_UART_HAL_PARITY_FIX0	(PCH_UART_LCR_0P)
+#define PCH_UART_HAL_5BIT		(PCH_UART_LCR_5BIT)
+#define PCH_UART_HAL_6BIT		(PCH_UART_LCR_6BIT)
+#define PCH_UART_HAL_7BIT		(PCH_UART_LCR_7BIT)
+#define PCH_UART_HAL_8BIT		(PCH_UART_LCR_8BIT)
+#define PCH_UART_HAL_STB1		0
+#define PCH_UART_HAL_STB2		(PCH_UART_LCR_STB)
+
+#define PCH_UART_HAL_CLR_TX_FIFO	(PCH_UART_FCR_TFR)
+#define PCH_UART_HAL_CLR_RX_FIFO	(PCH_UART_FCR_RFR)
+#define PCH_UART_HAL_CLR_ALL_FIFO	(PCH_UART_HAL_CLR_TX_FIFO | \
+					PCH_UART_HAL_CLR_RX_FIFO)
+
+#define PCH_UART_HAL_DMA_MODE0		0
+#define PCH_UART_HAL_FIFO_DIS		0
+#define PCH_UART_HAL_FIFO16		(PCH_UART_FCR_FIFOE)
+#define PCH_UART_HAL_FIFO256		(PCH_UART_FCR_FIFOE | \
+					PCH_UART_FCR_FIFO256)
+#define PCH_UART_HAL_FIFO64		(PCH_UART_HAL_FIFO256)
+#define PCH_UART_HAL_TRIGGER1		(PCH_UART_FCR_RFTL1)
+#define PCH_UART_HAL_TRIGGER64		(PCH_UART_FCR_RFTL64)
+#define PCH_UART_HAL_TRIGGER128		(PCH_UART_FCR_RFTL128)
+#define PCH_UART_HAL_TRIGGER224		(PCH_UART_FCR_RFTL224)
+#define PCH_UART_HAL_TRIGGER16		(PCH_UART_FCR_RFTL16)
+#define PCH_UART_HAL_TRIGGER32		(PCH_UART_FCR_RFTL32)
+#define PCH_UART_HAL_TRIGGER56		(PCH_UART_FCR_RFTL56)
+#define PCH_UART_HAL_TRIGGER4		(PCH_UART_FCR_RFTL4)
+#define PCH_UART_HAL_TRIGGER8		(PCH_UART_FCR_RFTL8)
+#define PCH_UART_HAL_TRIGGER14		(PCH_UART_FCR_RFTL14)
+#define PCH_UART_HAL_TRIGGER_L		(PCH_UART_FCR_RFTL64)
+#define PCH_UART_HAL_TRIGGER_M		(PCH_UART_FCR_RFTL128)
+#define PCH_UART_HAL_TRIGGER_H		(PCH_UART_FCR_RFTL224)
+
+#define PCH_UART_HAL_RX_INT		(PCH_UART_IER_ERBFI)
+#define PCH_UART_HAL_TX_INT		(PCH_UART_IER_ETBEI)
+#define PCH_UART_HAL_RX_ERR_INT		(PCH_UART_IER_ELSI)
+#define PCH_UART_HAL_MS_INT		(PCH_UART_IER_EDSSI)
+#define PCH_UART_HAL_ALL_INT		(PCH_UART_IER_MASK)
+
+#define PCH_UART_HAL_DTR		(PCH_UART_MCR_DTR)
+#define PCH_UART_HAL_RTS		(PCH_UART_MCR_RTS)
+#define PCH_UART_HAL_OUT		(PCH_UART_MCR_OUT)
+#define PCH_UART_HAL_LOOP		(PCH_UART_MCR_LOOP)
+#define PCH_UART_HAL_AFE		(PCH_UART_MCR_AFE)
+
+struct pch_uart_buffer {
+	unsigned char *buf;
+	int size;
+};
+
+struct eg20t_port {
+	struct uart_port port;
+	int port_type;
+	void __iomem *membase;
+	resource_size_t mapbase;
+	unsigned int iobase;
+	struct pci_dev *pdev;
+	int fifo_size;
+	int base_baud;
+	int start_tx;
+	int start_rx;
+	int tx_empty;
+	int int_dis_flag;
+	int trigger;
+	int trigger_level;
+	struct pch_uart_buffer rxbuf;
+	unsigned int dmsr;
+	unsigned int fcr;
+	unsigned int use_dma;
+	unsigned int use_dma_flag;
+	struct dma_async_tx_descriptor	*desc_tx;
+	struct dma_async_tx_descriptor	*desc_rx;
+	struct pch_dma_slave		param_tx;
+	struct pch_dma_slave		param_rx;
+	struct dma_chan			*chan_tx;
+	struct dma_chan			*chan_rx;
+	struct scatterlist		sg_tx;
+	struct scatterlist		sg_rx;
+	int				tx_dma_use;
+	void				*rx_buf_virt;
+	dma_addr_t			rx_buf_dma;
+};
+
+static unsigned int default_baud = 9600;
+static const int trigger_level_256[4] = { 1, 64, 128, 224 };
+static const int trigger_level_64[4] = { 1, 16, 32, 56 };
+static const int trigger_level_16[4] = { 1, 4, 8, 14 };
+static const int trigger_level_1[4] = { 1, 1, 1, 1 };
+
+static void pch_uart_hal_request(struct pci_dev *pdev, int fifosize,
+				 int base_baud)
+{
+	struct eg20t_port *priv = pci_get_drvdata(pdev);
+
+	priv->trigger_level = 1;
+	priv->fcr = 0;
+}
+
+static unsigned int get_msr(struct eg20t_port *priv, void __iomem *base)
+{
+	unsigned int msr = ioread8(base + UART_MSR);
+	priv->dmsr |= msr & PCH_UART_MSR_DELTA;
+
+	return msr;
+}
+
+static void pch_uart_hal_enable_interrupt(struct eg20t_port *priv,
+					  unsigned int flag)
+{
+	u8 ier = ioread8(priv->membase + UART_IER);
+	ier |= flag & PCH_UART_IER_MASK;
+	iowrite8(ier, priv->membase + UART_IER);
+}
+
+static void pch_uart_hal_disable_interrupt(struct eg20t_port *priv,
+					   unsigned int flag)
+{
+	u8 ier = ioread8(priv->membase + UART_IER);
+	ier &= ~(flag & PCH_UART_IER_MASK);
+	iowrite8(ier, priv->membase + UART_IER);
+}
+
+static int pch_uart_hal_set_line(struct eg20t_port *priv, int baud,
+				 unsigned int parity, unsigned int bits,
+				 unsigned int stb)
+{
+	unsigned int dll, dlm, lcr;
+	int div;
+
+	div = DIV_ROUND(priv->base_baud / 16, baud);
+	if (div < 0 || USHRT_MAX <= div) {
+		pr_err("Invalid Baud(div=0x%x)\n", div);
+		return -EINVAL;
+	}
+
+	dll = (unsigned int)div & 0x00FFU;
+	dlm = ((unsigned int)div >> 8) & 0x00FFU;
+
+	if (parity & ~(PCH_UART_LCR_PEN | PCH_UART_LCR_EPS | PCH_UART_LCR_SP)) {
+		pr_err("Invalid parity(0x%x)\n", parity);
+		return -EINVAL;
+	}
+
+	if (bits & ~PCH_UART_LCR_WLS) {
+		pr_err("Invalid bits(0x%x)\n", bits);
+		return -EINVAL;
+	}
+
+	if (stb & ~PCH_UART_LCR_STB) {
+		pr_err("Invalid STB(0x%x)\n", stb);
+		return -EINVAL;
+	}
+
+	lcr = parity;
+	lcr |= bits;
+	lcr |= stb;
+
+	pr_debug("%s:baud = %d, div = %04x, lcr = %02x (%lu)\n",
+		 __func__, baud, div, lcr, jiffies);
+	iowrite8(PCH_UART_LCR_DLAB, priv->membase + UART_LCR);
+	iowrite8(dll, priv->membase + PCH_UART_DLL);
+	iowrite8(dlm, priv->membase + PCH_UART_DLM);
+	iowrite8(lcr, priv->membase + UART_LCR);
+
+	return 0;
+}
+
+static int pch_uart_hal_fifo_reset(struct eg20t_port *priv,
+				    unsigned int flag)
+{
+	if (flag & ~(PCH_UART_FCR_TFR | PCH_UART_FCR_RFR)) {
+		pr_err("%s:Invalid flag(0x%x)\n", __func__, flag);
+		return -EINVAL;
+	}
+
+	iowrite8(PCH_UART_FCR_FIFOE | priv->fcr, priv->membase + UART_FCR);
+	iowrite8(PCH_UART_FCR_FIFOE | priv->fcr | flag,
+		 priv->membase + UART_FCR);
+	iowrite8(priv->fcr, priv->membase + UART_FCR);
+
+	return 0;
+}
+
+static int pch_uart_hal_set_fifo(struct eg20t_port *priv,
+				 unsigned int dmamode,
+				 unsigned int fifo_size, unsigned int trigger)
+{
+	u8 fcr;
+
+	if (dmamode & ~PCH_UART_FCR_DMS) {
+		pr_err("%s:Invalid DMA Mode(0x%x)\n", __func__, dmamode);
+		return -EINVAL;
+	}
+
+	if (fifo_size & ~(PCH_UART_FCR_FIFOE | PCH_UART_FCR_FIFO256)) {
+		pr_err("%s:Invalid FIFO SIZE(0x%x)\n", __func__, fifo_size);
+		return -EINVAL;
+	}
+
+	if (trigger & ~PCH_UART_FCR_RFTL) {
+		pr_err("%s:Invalid TRIGGER(0x%x)\n", __func__, trigger);
+		return -EINVAL;
+	}
+
+	switch (priv->fifo_size) {
+	case 256:
+		priv->trigger_level =
+		    trigger_level_256[trigger >> PCH_UART_FCR_RFTL_SHIFT];
+		break;
+	case 64:
+		priv->trigger_level =
+		    trigger_level_64[trigger >> PCH_UART_FCR_RFTL_SHIFT];
+		break;
+	case 16:
+		priv->trigger_level =
+		    trigger_level_16[trigger >> PCH_UART_FCR_RFTL_SHIFT];
+		break;
+	default:
+		priv->trigger_level =
+		    trigger_level_1[trigger >> PCH_UART_FCR_RFTL_SHIFT];
+		break;
+	}
+	fcr =
+	    dmamode | fifo_size | trigger | PCH_UART_FCR_RFR | PCH_UART_FCR_TFR;
+	iowrite8(PCH_UART_FCR_FIFOE, priv->membase + UART_FCR);
+	iowrite8(PCH_UART_FCR_FIFOE | PCH_UART_FCR_RFR | PCH_UART_FCR_TFR,
+		 priv->membase + UART_FCR);
+	iowrite8(fcr, priv->membase + UART_FCR);
+	priv->fcr = fcr;
+
+	return 0;
+}
+
+static u8 pch_uart_hal_get_modem(struct eg20t_port *priv)
+{
+	priv->dmsr = 0;
+	return get_msr(priv, priv->membase);
+}
+
+static int pch_uart_hal_write(struct eg20t_port *priv,
+			      const unsigned char *buf, int tx_size)
+{
+	int i;
+	unsigned int thr;
+
+	for (i = 0; i < tx_size;) {
+		thr = buf[i++];
+		iowrite8(thr, priv->membase + PCH_UART_THR);
+	}
+	return i;
+}
+
+static int pch_uart_hal_read(struct eg20t_port *priv, unsigned char *buf,
+			     int rx_size)
+{
+	int i;
+	u8 rbr, lsr;
+
+	lsr = ioread8(priv->membase + UART_LSR);
+	for (i = 0, lsr = ioread8(priv->membase + UART_LSR);
+	     i < rx_size && lsr & UART_LSR_DR;
+	     lsr = ioread8(priv->membase + UART_LSR)) {
+		rbr = ioread8(priv->membase + PCH_UART_RBR);
+		buf[i++] = rbr;
+	}
+	return i;
+}
+
+static unsigned int pch_uart_hal_get_iid(struct eg20t_port *priv)
+{
+	unsigned int iir;
+	int ret;
+
+	iir = ioread8(priv->membase + UART_IIR);
+	ret = (iir & (PCH_UART_IIR_IID | PCH_UART_IIR_TOI | PCH_UART_IIR_IP));
+	return ret;
+}
+
+static u8 pch_uart_hal_get_line_status(struct eg20t_port *priv)
+{
+	return ioread8(priv->membase + UART_LSR);
+}
+
+static void pch_uart_hal_set_break(struct eg20t_port *priv, int on)
+{
+	unsigned int lcr;
+
+	lcr = ioread8(priv->membase + UART_LCR);
+	if (on)
+		lcr |= PCH_UART_LCR_SB;
+	else
+		lcr &= ~PCH_UART_LCR_SB;
+
+	iowrite8(lcr, priv->membase + UART_LCR);
+}
+
+static int push_rx(struct eg20t_port *priv, const unsigned char *buf,
+		   int size)
+{
+	struct uart_port *port;
+	struct tty_struct *tty;
+
+	port = &priv->port;
+	tty = tty_port_tty_get(&port->state->port);
+	if (!tty) {
+		pr_debug("%s:tty is busy now", __func__);
+		return -EBUSY;
+	}
+
+	tty_insert_flip_string(tty, buf, size);
+	tty_flip_buffer_push(tty);
+	tty_kref_put(tty);
+
+	return 0;
+}
+
+static int pop_tx_x(struct eg20t_port *priv, unsigned char *buf)
+{
+	int ret;
+	struct uart_port *port = &priv->port;
+
+	if (port->x_char) {
+		pr_debug("%s:X character send %02x (%lu)\n", __func__,
+			port->x_char, jiffies);
+		buf[0] = port->x_char;
+		port->x_char = 0;
+		ret = 1;
+	} else {
+		ret = 0;
+	}
+
+	return ret;
+}
+
+static int dma_push_rx(struct eg20t_port *priv, int size)
+{
+	struct tty_struct *tty;
+	int room;
+	struct uart_port *port = &priv->port;
+
+	port = &priv->port;
+	tty = tty_port_tty_get(&port->state->port);
+	if (!tty) {
+		pr_debug("%s:tty is busy now", __func__);
+		return 0;
+	}
+
+	room = tty_buffer_request_room(tty, size);
+
+	if (room < size)
+		dev_warn(port->dev, "Rx overrun: dropping %u bytes\n",
+			 size - room);
+	if (!room)
+		return room;
+
+	tty_insert_flip_string(tty, sg_virt(&priv->sg_rx), size);
+
+	port->icount.rx += room;
+	tty_kref_put(tty);
+
+	return room;
+}
+
+static void pch_free_dma(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	priv = container_of(port, struct eg20t_port, port);
+
+	if (priv->chan_tx) {
+		dma_release_channel(priv->chan_tx);
+		priv->chan_tx = NULL;
+	}
+	if (priv->chan_rx) {
+		dma_release_channel(priv->chan_rx);
+		priv->chan_rx = NULL;
+	}
+	if (sg_dma_address(&priv->sg_rx))
+		dma_free_coherent(port->dev, port->fifosize,
+				  sg_virt(&priv->sg_rx),
+				  sg_dma_address(&priv->sg_rx));
+
+	return;
+}
+
+static bool filter(struct dma_chan *chan, void *slave)
+{
+	struct pch_dma_slave *param = slave;
+
+	if ((chan->chan_id == param->chan_id) && (param->dma_dev ==
+						  chan->device->dev)) {
+		chan->private = param;
+		return true;
+	} else {
+		return false;
+	}
+}
+
+static void pch_request_dma(struct uart_port *port)
+{
+	dma_cap_mask_t mask;
+	struct dma_chan *chan;
+	struct pci_dev *dma_dev;
+	struct pch_dma_slave *param;
+	struct eg20t_port *priv =
+				container_of(port, struct eg20t_port, port);
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	dma_dev = pci_get_bus_and_slot(2, PCI_DEVFN(0xa, 0)); /* Get DMA's dev
+								information */
+	/* Set Tx DMA */
+	param = &priv->param_tx;
+	param->dma_dev = &dma_dev->dev;
+	param->chan_id = priv->port.line;
+	param->tx_reg = port->mapbase + UART_TX;
+	chan = dma_request_channel(mask, filter, param);
+	if (!chan) {
+		pr_err("%s:dma_request_channel FAILS(Tx)\n", __func__);
+		return;
+	}
+	priv->chan_tx = chan;
+
+	/* Set Rx DMA */
+	param = &priv->param_rx;
+	param->dma_dev = &dma_dev->dev;
+	param->chan_id = priv->port.line + 1; /* Rx = Tx + 1 */
+	param->rx_reg = port->mapbase + UART_RX;
+	chan = dma_request_channel(mask, filter, param);
+	if (!chan) {
+		pr_err("%s:dma_request_channel FAILS(Rx)\n", __func__);
+		dma_release_channel(priv->chan_tx);
+		return;
+	}
+
+	/* Get Consistent memory for DMA */
+	priv->rx_buf_virt = dma_alloc_coherent(port->dev, port->fifosize,
+				    &priv->rx_buf_dma, GFP_KERNEL);
+	priv->chan_rx = chan;
+}
+
+static void pch_dma_rx_complete(void *arg)
+{
+	struct eg20t_port *priv = arg;
+	struct uart_port *port = &priv->port;
+	struct tty_struct *tty = tty_port_tty_get(&port->state->port);
+
+	if (!tty) {
+		pr_debug("%s:tty is busy now", __func__);
+		return;
+	}
+
+	if (dma_push_rx(priv, priv->trigger_level))
+		tty_flip_buffer_push(tty);
+
+	tty_kref_put(tty);
+}
+
+static void pch_dma_tx_complete(void *arg)
+{
+	struct eg20t_port *priv = arg;
+	struct uart_port *port = &priv->port;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	xmit->tail += sg_dma_len(&priv->sg_tx);
+	xmit->tail &= UART_XMIT_SIZE - 1;
+	port->icount.tx += sg_dma_len(&priv->sg_tx);
+
+	async_tx_ack(priv->desc_tx);
+	priv->tx_dma_use = 0;
+}
+
+static int pop_tx(struct eg20t_port *priv, unsigned char *buf, int size)
+{
+	int count = 0;
+	struct uart_port *port = &priv->port;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	if (uart_tx_stopped(port) || uart_circ_empty(xmit) || count >= size)
+		goto pop_tx_end;
+
+	do {
+		int cnt_to_end =
+		    CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+		int sz = min(size - count, cnt_to_end);
+		memcpy(&buf[count], &xmit->buf[xmit->tail], sz);
+		xmit->tail = (xmit->tail + sz) & (UART_XMIT_SIZE - 1);
+		count += sz;
+	} while (!uart_circ_empty(xmit) && count < size);
+
+pop_tx_end:
+	pr_debug("%d characters. Remained %d characters. (%lu)\n",
+		 count, size - count, jiffies);
+
+	return count;
+}
+
+static int handle_rx_to(struct eg20t_port *priv)
+{
+	struct pch_uart_buffer *buf;
+	int rx_size;
+	int ret;
+	if (!priv->start_rx) {
+		pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT);
+		return 0;
+	}
+	buf = &priv->rxbuf;
+	do {
+		rx_size = pch_uart_hal_read(priv, buf->buf, buf->size);
+		ret = push_rx(priv, buf->buf, rx_size);
+		if (ret)
+			return 0;
+	} while (rx_size == buf->size);
+
+	return PCH_UART_HANDLED_RX_INT;
+}
+
+static int handle_rx(struct eg20t_port *priv)
+{
+	return handle_rx_to(priv);
+}
+
+static int dma_handle_rx(struct eg20t_port *priv)
+{
+	struct uart_port *port = &priv->port;
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist *sg;
+
+	priv = container_of(port, struct eg20t_port, port);
+	sg = &priv->sg_rx;
+
+	sg_init_table(&priv->sg_rx, 1); /* Initialize SG table */
+
+	sg_dma_len(sg) = priv->fifo_size;
+
+	sg_set_page(&priv->sg_rx, virt_to_page(priv->rx_buf_virt),
+		     sg_dma_len(sg), (int)priv->rx_buf_virt & ~PAGE_MASK);
+
+	sg_dma_address(sg) = priv->rx_buf_dma;
+
+	desc = priv->chan_rx->device->device_prep_slave_sg(priv->chan_rx,
+			sg, 1, DMA_FROM_DEVICE,
+			DMA_PREP_INTERRUPT);
+	if (!desc)
+		return 0;
+
+	priv->desc_rx = desc;
+	desc->callback = pch_dma_rx_complete;
+	desc->callback_param = priv;
+	desc->tx_submit(desc);
+	dma_async_issue_pending(priv->chan_rx);
+
+	return PCH_UART_HANDLED_RX_INT;
+}
+
+static unsigned int handle_tx(struct eg20t_port *priv)
+{
+	struct uart_port *port = &priv->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	int ret;
+	int fifo_size;
+	int tx_size;
+	int size;
+	int tx_empty;
+
+	if (!priv->start_tx) {
+		pr_info("%s:Tx isn't started. (%lu)\n", __func__, jiffies);
+		pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+		priv->tx_empty = 1;
+		return 0;
+	}
+
+	fifo_size = max(priv->fifo_size, 1);
+	tx_empty = 1;
+	if (pop_tx_x(priv, xmit->buf)) {
+		pch_uart_hal_write(priv, xmit->buf, 1);
+		port->icount.tx++;
+		tx_empty = 0;
+		fifo_size--;
+	}
+	size = min(xmit->head - xmit->tail, fifo_size);
+	tx_size = pop_tx(priv, xmit->buf, size);
+	if (tx_size > 0) {
+		ret = pch_uart_hal_write(priv, xmit->buf, tx_size);
+		port->icount.tx += ret;
+		tx_empty = 0;
+	}
+
+	priv->tx_empty = tx_empty;
+
+	if (tx_empty)
+		pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+
+	return PCH_UART_HANDLED_TX_INT;
+}
+
+static unsigned int dma_handle_tx(struct eg20t_port *priv)
+{
+	struct uart_port *port = &priv->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	struct scatterlist *sg = &priv->sg_tx;
+	int nent;
+	int fifo_size;
+	int tx_empty;
+	struct dma_async_tx_descriptor *desc;
+
+	if (!priv->start_tx) {
+		pr_info("%s:Tx isn't started. (%lu)\n", __func__, jiffies);
+		pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+		priv->tx_empty = 1;
+		return 0;
+	}
+
+	fifo_size = max(priv->fifo_size, 1);
+	tx_empty = 1;
+	if (pop_tx_x(priv, xmit->buf)) {
+		pch_uart_hal_write(priv, xmit->buf, 1);
+		port->icount.tx++;
+		tx_empty = 0;
+		fifo_size--;
+	}
+
+	pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_TX_INT);
+
+	priv->tx_dma_use = 1;
+
+	sg_init_table(&priv->sg_tx, 1); /* Initialize SG table */
+
+	sg_set_page(&priv->sg_tx, virt_to_page(xmit->buf),
+		    UART_XMIT_SIZE, (int)xmit->buf & ~PAGE_MASK);
+
+	nent = dma_map_sg(port->dev, &priv->sg_tx, 1, DMA_TO_DEVICE);
+	if (!nent) {
+		pr_err("%s:dma_map_sg Failed\n", __func__);
+		return 0;
+	}
+
+	sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
+	sg_dma_address(sg) = (sg_dma_address(sg) & ~(UART_XMIT_SIZE - 1)) +
+			      sg->offset;
+	sg_dma_len(sg) = min((int)CIRC_CNT(xmit->head, xmit->tail,
+			     UART_XMIT_SIZE), CIRC_CNT_TO_END(xmit->head,
+			     xmit->tail, UART_XMIT_SIZE));
+
+	desc = priv->chan_tx->device->device_prep_slave_sg(priv->chan_tx,
+		sg, nent, DMA_TO_DEVICE, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
+	if (!desc) {
+		pr_err("%s:device_prep_slave_sg Failed\n", __func__);
+		return 0;
+	}
+
+	dma_sync_sg_for_device(port->dev, sg, 1, DMA_TO_DEVICE);
+
+	priv->desc_tx = desc;
+	desc->callback = pch_dma_tx_complete;
+	desc->callback_param = priv;
+
+	desc->tx_submit(desc);
+
+	dma_async_issue_pending(priv->chan_tx);
+
+	return PCH_UART_HANDLED_TX_INT;
+}
+
+static void pch_uart_err_ir(struct eg20t_port *priv, unsigned int lsr)
+{
+	u8 fcr = ioread8(priv->membase + UART_FCR);
+
+	/* Reset FIFO */
+	fcr |= UART_FCR_CLEAR_RCVR;
+	iowrite8(fcr, priv->membase + UART_FCR);
+
+	if (lsr & PCH_UART_LSR_ERR)
+		dev_err(&priv->pdev->dev, "Error data in FIFO\n");
+
+	if (lsr & UART_LSR_FE)
+		dev_err(&priv->pdev->dev, "Framing Error\n");
+
+	if (lsr & UART_LSR_PE)
+		dev_err(&priv->pdev->dev, "Parity Error\n");
+
+	if (lsr & UART_LSR_OE)
+		dev_err(&priv->pdev->dev, "Overrun Error\n");
+}
+
+static irqreturn_t pch_uart_interrupt(int irq, void *dev_id)
+{
+	struct eg20t_port *priv = dev_id;
+	unsigned int handled;
+	u8 lsr;
+	int ret = 0;
+	unsigned int iid;
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->port.lock, flags);
+	handled = 0;
+	while ((iid = pch_uart_hal_get_iid(priv)) > 1) {
+		switch (iid) {
+		case PCH_UART_IID_RLS:	/* Receiver Line Status */
+			lsr = pch_uart_hal_get_line_status(priv);
+			if (lsr & (PCH_UART_LSR_ERR | UART_LSR_FE |
+						UART_LSR_PE | UART_LSR_OE)) {
+				pch_uart_err_ir(priv, lsr);
+				ret = PCH_UART_HANDLED_RX_ERR_INT;
+			}
+			break;
+		case PCH_UART_IID_RDR:	/* Received Data Ready */
+			if (priv->use_dma)
+				ret = dma_handle_rx(priv);
+			else
+				ret = handle_rx(priv);
+			break;
+		case PCH_UART_IID_RDR_TO:	/* Received Data Ready
+						   (FIFO Timeout) */
+			ret = handle_rx_to(priv);
+			break;
+		case PCH_UART_IID_THRE:	/* Transmitter Holding Register
+						   Empty */
+			if (priv->use_dma)
+				ret = dma_handle_tx(priv);
+			else
+				ret = handle_tx(priv);
+			break;
+		case PCH_UART_IID_MS:	/* Modem Status */
+			ret = PCH_UART_HANDLED_MS_INT;
+			break;
+		default:	/* Never junp to this label */
+			pr_err("%s:iid=%d (%lu)\n", __func__, iid, jiffies);
+			ret = -1;
+			break;
+		}
+		handled |= (unsigned int)ret;
+	}
+	if (handled == 0 && iid <= 1) {
+		if (priv->int_dis_flag)
+			priv->int_dis_flag = 0;
+	}
+
+	spin_unlock_irqrestore(&priv->port.lock, flags);
+	return IRQ_RETVAL(handled);
+}
+
+/* This function tests whether the transmitter fifo and shifter for the port
+						described by 'port' is empty. */
+static unsigned int pch_uart_tx_empty(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	int ret;
+	priv = container_of(port, struct eg20t_port, port);
+	if (priv->tx_empty)
+		ret = TIOCSER_TEMT;
+	else
+		ret = 0;
+
+	return ret;
+}
+
+/* Returns the current state of modem control inputs. */
+static unsigned int pch_uart_get_mctrl(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	u8 modem;
+	unsigned int ret = 0;
+
+	priv = container_of(port, struct eg20t_port, port);
+	modem = pch_uart_hal_get_modem(priv);
+
+	if (modem & UART_MSR_DCD)
+		ret |= TIOCM_CAR;
+
+	if (modem & UART_MSR_RI)
+		ret |= TIOCM_RNG;
+
+	if (modem & UART_MSR_DSR)
+		ret |= TIOCM_DSR;
+
+	if (modem & UART_MSR_CTS)
+		ret |= TIOCM_CTS;
+
+	return ret;
+}
+
+static void pch_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+	u32 mcr = 0;
+	unsigned int dat;
+	struct eg20t_port *priv = container_of(port, struct eg20t_port, port);
+
+	if (mctrl & TIOCM_DTR)
+		mcr |= UART_MCR_DTR;
+	if (mctrl & TIOCM_RTS)
+		mcr |= UART_MCR_RTS;
+	if (mctrl & TIOCM_LOOP)
+		mcr |= UART_MCR_LOOP;
+
+	if (mctrl) {
+		dat = pch_uart_get_mctrl(port);
+		dat |= mcr;
+		iowrite8(dat, priv->membase + UART_MCR);
+	}
+}
+
+static void pch_uart_stop_tx(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	priv = container_of(port, struct eg20t_port, port);
+	priv->start_tx = 0;
+	priv->tx_dma_use = 0;
+}
+
+static void pch_uart_start_tx(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+
+	priv = container_of(port, struct eg20t_port, port);
+
+	if (priv->use_dma)
+		if (priv->tx_dma_use)
+			return;
+
+	priv->start_tx = 1;
+	pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_TX_INT);
+}
+
+static void pch_uart_stop_rx(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	priv = container_of(port, struct eg20t_port, port);
+	priv->start_rx = 0;
+	pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_RX_INT);
+	priv->int_dis_flag = 1;
+}
+
+/* Enable the modem status interrupts. */
+static void pch_uart_enable_ms(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	priv = container_of(port, struct eg20t_port, port);
+	pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_MS_INT);
+}
+
+/* Control the transmission of a break signal. */
+static void pch_uart_break_ctl(struct uart_port *port, int ctl)
+{
+	struct eg20t_port *priv;
+	unsigned long flags;
+
+	priv = container_of(port, struct eg20t_port, port);
+	spin_lock_irqsave(&port->lock, flags);
+	pch_uart_hal_set_break(priv, ctl);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* Grab any interrupt resources and initialise any low level driver state. */
+static int pch_uart_startup(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	int ret;
+	int fifo_size;
+	int trigger_level;
+
+	priv = container_of(port, struct eg20t_port, port);
+	priv->tx_empty = 1;
+	port->uartclk = priv->base_baud;
+	pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
+	ret = pch_uart_hal_set_line(priv, default_baud,
+			      PCH_UART_HAL_PARITY_NONE, PCH_UART_HAL_8BIT,
+			      PCH_UART_HAL_STB1);
+	if (ret)
+		return ret;
+
+	switch (priv->fifo_size) {
+	case 256:
+		fifo_size = PCH_UART_HAL_FIFO256;
+		break;
+	case 64:
+		fifo_size = PCH_UART_HAL_FIFO64;
+		break;
+	case 16:
+		fifo_size = PCH_UART_HAL_FIFO16;
+	case 1:
+	default:
+		fifo_size = PCH_UART_HAL_FIFO_DIS;
+		break;
+	}
+
+	switch (priv->trigger) {
+	case PCH_UART_HAL_TRIGGER1:
+		trigger_level = 1;
+		break;
+	case PCH_UART_HAL_TRIGGER_L:
+		trigger_level = priv->fifo_size / 4;
+		break;
+	case PCH_UART_HAL_TRIGGER_M:
+		trigger_level = priv->fifo_size / 2;
+		break;
+	case PCH_UART_HAL_TRIGGER_H:
+	default:
+		trigger_level = priv->fifo_size - (priv->fifo_size / 8);
+		break;
+	}
+
+	priv->trigger_level = trigger_level;
+	ret = pch_uart_hal_set_fifo(priv, PCH_UART_HAL_DMA_MODE0,
+				    fifo_size, priv->trigger);
+	if (ret < 0)
+		return ret;
+
+	ret = request_irq(priv->port.irq, pch_uart_interrupt, IRQF_SHARED,
+			KBUILD_MODNAME, priv);
+	if (ret < 0)
+		return ret;
+
+	if (priv->use_dma)
+		pch_request_dma(port);
+
+	priv->start_rx = 1;
+	pch_uart_hal_enable_interrupt(priv, PCH_UART_HAL_RX_INT);
+	uart_update_timeout(port, CS8, default_baud);
+
+	return 0;
+}
+
+static void pch_uart_shutdown(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	int ret;
+
+	priv = container_of(port, struct eg20t_port, port);
+	pch_uart_hal_disable_interrupt(priv, PCH_UART_HAL_ALL_INT);
+	pch_uart_hal_fifo_reset(priv, PCH_UART_HAL_CLR_ALL_FIFO);
+	ret = pch_uart_hal_set_fifo(priv, PCH_UART_HAL_DMA_MODE0,
+			      PCH_UART_HAL_FIFO_DIS, PCH_UART_HAL_TRIGGER1);
+	if (ret)
+		pr_err("pch_uart_hal_set_fifo Failed(ret=%d)\n", ret);
+
+	if (priv->use_dma_flag)
+		pch_free_dma(port);
+
+	free_irq(priv->port.irq, priv);
+}
+
+/* Change the port parameters, including word length, parity, stop
+ *bits.  Update read_status_mask and ignore_status_mask to indicate
+ *the types of events we are interested in receiving.  */
+static void pch_uart_set_termios(struct uart_port *port,
+				 struct ktermios *termios, struct ktermios *old)
+{
+	int baud;
+	int rtn;
+	unsigned int parity, bits, stb;
+	struct eg20t_port *priv;
+	unsigned long flags;
+
+	priv = container_of(port, struct eg20t_port, port);
+	switch (termios->c_cflag & CSIZE) {
+	case CS5:
+		bits = PCH_UART_HAL_5BIT;
+		break;
+	case CS6:
+		bits = PCH_UART_HAL_6BIT;
+		break;
+	case CS7:
+		bits = PCH_UART_HAL_7BIT;
+		break;
+	default:		/* CS8 */
+		bits = PCH_UART_HAL_8BIT;
+		break;
+	}
+	if (termios->c_cflag & CSTOPB)
+		stb = PCH_UART_HAL_STB2;
+	else
+		stb = PCH_UART_HAL_STB1;
+
+	if (termios->c_cflag & PARENB) {
+		if (!(termios->c_cflag & PARODD))
+			parity = PCH_UART_HAL_PARITY_ODD;
+		else
+			parity = PCH_UART_HAL_PARITY_EVEN;
+
+	} else {
+		parity = PCH_UART_HAL_PARITY_NONE;
+	}
+	termios->c_cflag &= ~CMSPAR; /* Mark/Space parity is not supported */
+
+	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	uart_update_timeout(port, termios->c_cflag, baud);
+	rtn = pch_uart_hal_set_line(priv, baud, parity, bits, stb);
+	if (rtn)
+		goto out;
+
+	/* Don't rewrite B0 */
+	if (tty_termios_baud_rate(termios))
+		tty_termios_encode_baud_rate(termios, baud, baud);
+
+out:
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *pch_uart_type(struct uart_port *port)
+{
+	return KBUILD_MODNAME;
+}
+
+static void pch_uart_release_port(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+
+	priv = container_of(port, struct eg20t_port, port);
+	pci_iounmap(priv->pdev, priv->membase);
+	pci_release_regions(priv->pdev);
+}
+
+static int pch_uart_request_port(struct uart_port *port)
+{
+	struct eg20t_port *priv;
+	int ret;
+	void __iomem *membase;
+
+	priv = container_of(port, struct eg20t_port, port);
+	ret = pci_request_regions(priv->pdev, KBUILD_MODNAME);
+	if (ret < 0)
+		return -EBUSY;
+
+	membase = pci_iomap(priv->pdev, 1, 0);
+	if (!membase) {
+		pci_release_regions(priv->pdev);
+		return -EBUSY;
+	}
+	priv->membase = port->membase = membase;
+
+	return 0;
+}
+
+static void pch_uart_config_port(struct uart_port *port, int type)
+{
+	struct eg20t_port *priv;
+
+	priv = container_of(port, struct eg20t_port, port);
+	if (type & UART_CONFIG_TYPE) {
+		port->type = priv->port_type;
+		pch_uart_request_port(port);
+	}
+}
+
+static int pch_uart_verify_port(struct uart_port *port,
+				struct serial_struct *serinfo)
+{
+	struct eg20t_port *priv;
+
+	priv = container_of(port, struct eg20t_port, port);
+	if (serinfo->flags & UPF_LOW_LATENCY) {
+		pr_info("PCH UART : Use PIO Mode (without DMA)\n");
+		priv->use_dma = 0;
+		serinfo->flags &= ~UPF_LOW_LATENCY;
+	} else {
+#ifndef CONFIG_PCH_DMA
+		pr_err("%s : PCH DMA is not Loaded.\n", __func__);
+		return -EOPNOTSUPP;
+#endif
+		priv->use_dma = 1;
+		priv->use_dma_flag = 1;
+		pr_info("PCH UART : Use DMA Mode\n");
+	}
+
+	return 0;
+}
+
+static struct uart_ops pch_uart_ops = {
+	.tx_empty = pch_uart_tx_empty,
+	.set_mctrl = pch_uart_set_mctrl,
+	.get_mctrl = pch_uart_get_mctrl,
+	.stop_tx = pch_uart_stop_tx,
+	.start_tx = pch_uart_start_tx,
+	.stop_rx = pch_uart_stop_rx,
+	.enable_ms = pch_uart_enable_ms,
+	.break_ctl = pch_uart_break_ctl,
+	.startup = pch_uart_startup,
+	.shutdown = pch_uart_shutdown,
+	.set_termios = pch_uart_set_termios,
+/*	.pm		= pch_uart_pm,		Not supported yet */
+/*	.set_wake	= pch_uart_set_wake,	Not supported yet */
+	.type = pch_uart_type,
+	.release_port = pch_uart_release_port,
+	.request_port = pch_uart_request_port,
+	.config_port = pch_uart_config_port,
+	.verify_port = pch_uart_verify_port
+};
+
+static struct uart_driver pch_uart_driver = {
+	.owner = THIS_MODULE,
+	.driver_name = KBUILD_MODNAME,
+	.dev_name = PCH_UART_DRIVER_DEVICE,
+	.major = 0,
+	.minor = 0,
+	.nr = PCH_UART_NR,
+};
+
+static struct eg20t_port *pch_uart_init_port(struct pci_dev *pdev,
+						int port_type)
+{
+	struct eg20t_port *priv;
+	int ret;
+	unsigned int iobase;
+	unsigned int mapbase;
+	unsigned int rxbuf;
+	int fifosize, base_baud;
+	static int num;
+
+	priv = kzalloc(sizeof(struct eg20t_port), GFP_KERNEL);
+	if (priv == NULL)
+		goto init_port_alloc_err;
+
+	rxbuf = __get_free_page(GFP_KERNEL);
+	if (!rxbuf)
+		goto init_port_free_txbuf;
+
+	switch (port_type) {
+	case PORT_UNKNOWN:
+		fifosize = 256; /* UART0 */
+		base_baud = 1843200; /* 1.8432MHz */
+		break;
+	case PORT_8250:
+		fifosize = 64; /* UART1~3 */
+		base_baud = 1843200; /* 1.8432MHz */
+		break;
+	default:
+		dev_err(&pdev->dev, "Invalid Port Type(=%d)\n", port_type);
+		goto init_port_hal_free;
+	}
+
+	iobase = pci_resource_start(pdev, 0);
+	mapbase = pci_resource_start(pdev, 1);
+	priv->mapbase = mapbase;
+	priv->iobase = iobase;
+	priv->pdev = pdev;
+	priv->tx_empty = 1;
+	priv->rxbuf.buf = (unsigned char *)rxbuf;
+	priv->rxbuf.size = PAGE_SIZE;
+
+	priv->fifo_size = fifosize;
+	priv->base_baud = base_baud;
+	priv->port_type = PORT_MAX_8250 + port_type + 1;
+	priv->port.dev = &pdev->dev;
+	priv->port.iobase = iobase;
+	priv->port.membase = NULL;
+	priv->port.mapbase = mapbase;
+	priv->port.irq = pdev->irq;
+	priv->port.iotype = UPIO_PORT;
+	priv->port.ops = &pch_uart_ops;
+	priv->port.flags = UPF_BOOT_AUTOCONF;
+	priv->port.fifosize = fifosize;
+	priv->port.line = num++;
+	priv->trigger = PCH_UART_HAL_TRIGGER_M;
+
+	pci_set_drvdata(pdev, priv);
+	pch_uart_hal_request(pdev, fifosize, base_baud);
+	ret = uart_add_one_port(&pch_uart_driver, &priv->port);
+	if (ret < 0)
+		goto init_port_hal_free;
+
+	return priv;
+
+init_port_hal_free:
+	free_page(rxbuf);
+init_port_free_txbuf:
+	kfree(priv);
+init_port_alloc_err:
+
+	return NULL;
+}
+
+static void pch_uart_exit_port(struct eg20t_port *priv)
+{
+	uart_remove_one_port(&pch_uart_driver, &priv->port);
+	pci_set_drvdata(priv->pdev, NULL);
+	free_page((unsigned int)priv->rxbuf.buf);
+}
+
+static void pch_uart_pci_remove(struct pci_dev *pdev)
+{
+	struct eg20t_port *priv;
+
+	priv = (struct eg20t_port *)pci_get_drvdata(pdev);
+	pch_uart_exit_port(priv);
+	pci_disable_device(pdev);
+	kfree(priv);
+	return;
+}
+#ifdef CONFIG_PM
+static int pch_uart_pci_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	struct eg20t_port *priv = pci_get_drvdata(pdev);
+
+	uart_suspend_port(&pch_uart_driver, &priv->port);
+
+	pci_save_state(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+	return 0;
+}
+
+static int pch_uart_pci_resume(struct pci_dev *pdev)
+{
+	struct eg20t_port *priv = pci_get_drvdata(pdev);
+	int ret;
+
+	pci_set_power_state(pdev, PCI_D0);
+	pci_restore_state(pdev);
+
+	ret = pci_enable_device(pdev);
+	if (ret) {
+		dev_err(&pdev->dev,
+		"%s-pci_enable_device failed(ret=%d) ", __func__, ret);
+		return ret;
+	}
+
+	uart_resume_port(&pch_uart_driver, &priv->port);
+
+	return 0;
+}
+#else
+#define pch_uart_pci_suspend NULL
+#define pch_uart_pci_resume NULL
+#endif
+
+static DEFINE_PCI_DEVICE_TABLE(pch_uart_pci_id) = {
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8811),
+	 .driver_data = PCH_UART_8LINE},
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8812),
+	 .driver_data = PCH_UART_2LINE},
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8813),
+	 .driver_data = PCH_UART_2LINE},
+	{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x8814),
+	 .driver_data = PCH_UART_2LINE},
+	{0,},
+};
+
+static int __devinit pch_uart_pci_probe(struct pci_dev *pdev,
+					const struct pci_device_id *id)
+{
+	int ret;
+	struct eg20t_port *priv;
+
+	ret = pci_enable_device(pdev);
+	if (ret < 0)
+		goto probe_error;
+
+	priv = pch_uart_init_port(pdev, id->driver_data);
+	if (!priv) {
+		ret = -EBUSY;
+		goto probe_disable_device;
+	}
+	pci_set_drvdata(pdev, priv);
+
+	return ret;
+
+probe_disable_device:
+	pci_disable_device(pdev);
+probe_error:
+	return ret;
+}
+
+static struct pci_driver pch_uart_pci_driver = {
+	.name = "pch_uart",
+	.id_table = pch_uart_pci_id,
+	.probe = pch_uart_pci_probe,
+	.remove = __devexit_p(pch_uart_pci_remove),
+	.suspend = pch_uart_pci_suspend,
+	.resume = pch_uart_pci_resume,
+};
+
+static int __init pch_uart_module_init(void)
+{
+	int ret;
+
+	/* register as UART driver */
+	ret = uart_register_driver(&pch_uart_driver);
+	if (ret < 0)
+		return ret;
+
+	/* register as PCI driver */
+	ret = pci_register_driver(&pch_uart_pci_driver);
+	if (ret < 0)
+		uart_unregister_driver(&pch_uart_driver);
+
+	return ret;
+}
+module_init(pch_uart_module_init);
+
+static void __exit pch_uart_module_exit(void)
+{
+	pci_unregister_driver(&pch_uart_pci_driver);
+	uart_unregister_driver(&pch_uart_driver);
+}
+module_exit(pch_uart_module_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel EG20T PCH UART PCI Driver");
+module_param(default_baud, uint, S_IRUGO);