Re: [PATCH V2] tty/serial: add support for Xilinx PS UART

Michal Simek
2011-04-22T09:11:15Z

John Linn wrote:
> The Xilinx PS Uart is used on the new ARM based SoC. This
> UART is not compatible with others such that a seperate
> driver is required.
>
> Signed-off-by: John Linn <john.linn@xilinx.com>
> ---
>
> V2 Changes
>
> Updated based on Alan Cox and Greg KH comments. Thanks for their input.
> I hope I corrected everything as expected.
>
> 1. Now using dynamic device nodes so Doc*/devices.txt removed from patch.
> 2. Other minor updates based on Alan's input.
>
> drivers/tty/serial/Kconfig | 13 +
> drivers/tty/serial/Makefile | 1 +
> drivers/tty/serial/xilinx_uartps.c | 1121 ++++++++++++++++++++++++++++++++++++
> include/linux/serial_core.h | 3 +
> 4 files changed, 1138 insertions(+), 0 deletions(-)
> create mode 100644 drivers/tty/serial/xilinx_uartps.c
>
> diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
> index 80484af..84876ec 100644
> --- a/drivers/tty/serial/Kconfig
> +++ b/drivers/tty/serial/Kconfig
> @@ -1612,4 +1612,17 @@ config SERIAL_MXS_AUART_CONSOLE
> help
> Enable a MXS AUART port to be the system console.
>
> +config SERIAL_XILINX_PS_UART
> + tristate "Xilinx PS UART support"
> + select SERIAL_CORE
> + help
> + This driver supports the Xilinx PS UART port.
> +
> +config SERIAL_XILINX_PS_UART_CONSOLE
> + bool "Xilinx PS UART console support"
> + depends on SERIAL_XILINX_PS_UART=y
> + select SERIAL_CORE_CONSOLE
> + help
> + Enable a Xilinx PS UART port to be the system console.
> +
> endmenu
> diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
> index fee0690..aafddf1 100644
> --- a/drivers/tty/serial/Makefile
> +++ b/drivers/tty/serial/Makefile
> @@ -94,3 +94,4 @@ obj-$(CONFIG_SERIAL_IFX6X60) += ifx6x60.o
> obj-$(CONFIG_SERIAL_PCH_UART) += pch_uart.o
> obj-$(CONFIG_SERIAL_MSM_SMD) += msm_smd_tty.o
> obj-$(CONFIG_SERIAL_MXS_AUART) += mxs-auart.o
> +obj-$(CONFIG_SERIAL_XILINX_PS_UART) += xilinx_uartps.o
> diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
> new file mode 100644
> index 0000000..814fb5b
> --- /dev/null
> +++ b/drivers/tty/serial/xilinx_uartps.c
> @@ -0,0 +1,1121 @@
> +/*
> + * Xilinx PS UART driver
> + *
> + * 2011 (c) Xilinx 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/platform_device.h>
> +#include <linux/serial_core.h>
> +#include <linux/console.h>
> +#include <linux/serial.h>
> +#include <linux/irq.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +
> +#define XUARTPS_TTY_NAME "ttyPS"
> +#define XUARTPS_NAME "xuartps"
> +#define XUARTPS_MAJOR 0 /* use dynamic node allocation */
> +#define XUARTPS_MINOR 0 /* works best with devtmpfs */
> +#define XUARTPS_NR_PORTS 2
> +#define XUARTPS_FIFO_SIZE 16 /* FIFO size */
> +#define XUARTPS_REGISTER_SPACE 0xFFF
> +
> +#define xuartps_readl(offset) ioread32(port->membase + offset)
> +#define xuartps_writel(val, offset) iowrite32(val, port->membase + offset)
> +
> +/********************************Register Map********************************/
> +/** UART
> + *
> + * Register offsets for the UART.
> + *
> + */
> +#define XUARTPS_CR_OFFSET 0x00 /* Control Register [8:0] */
> +#define XUARTPS_MR_OFFSET 0x04 /* Mode Register [10:0] */
> +#define XUARTPS_IER_OFFSET 0x08 /* Interrupt Enable [10:0] */
> +#define XUARTPS_IDR_OFFSET 0x0C /* Interrupt Disable [10:0] */
> +#define XUARTPS_IMR_OFFSET 0x10 /* Interrupt Mask [10:0] */
> +#define XUARTPS_ISR_OFFSET 0x14 /* Interrupt Status [10:0]*/
> +#define XUARTPS_BAUDGEN_OFFSET 0x18 /* Baud Rate Generator [15:0] */
> +#define XUARTPS_RXTOUT_OFFSET 0x1C /* RX Timeout [7:0] */
> +#define XUARTPS_RXWM_OFFSET 0x20 /* RX FIFO Trigger Level [5:0] */
> +#define XUARTPS_MODEMCR_OFFSET 0x24 /* Modem Control [5:0] */
> +#define XUARTPS_MODEMSR_OFFSET 0x28 /* Modem Status [8:0] */
> +#define XUARTPS_SR_OFFSET 0x2C /* Channel Status [11:0] */
> +#define XUARTPS_FIFO_OFFSET 0x30 /* FIFO [15:0] or [7:0] */
> +#define XUARTPS_BAUDDIV_OFFSET 0x34 /* Baud Rate Divider [7:0] */
> +#define XUARTPS_FLOWDEL_OFFSET 0x38 /* Flow Delay [15:0] */
> +#define XUARTPS_IRRX_PWIDTH_OFFSET 0x3C /* IR Minimum Received Pulse
> + Width [15:0] */
> +#define XUARTPS_IRTX_PWIDTH_OFFSET 0x40 /* IR Transmitted pulse
> + Width [7:0] */
> +#define XUARTPS_TXWM_OFFSET 0x44 /* TX FIFO Trigger Level [5:0] */
> +
> +/** Control Register
> + *
> + * The Control register (CR) controls the major functions of the device.
> + *
> + * Control Register Bit Definitions
> + */
> +#define XUARTPS_CR_STOPBRK 0x00000100 /* Stop TX break */
> +#define XUARTPS_CR_STARTBRK 0x00000080 /* Set TX break */
> +#define XUARTPS_CR_TX_DIS 0x00000020 /* TX disabled. */
> +#define XUARTPS_CR_TX_EN 0x00000010 /* TX enabled */
> +#define XUARTPS_CR_RX_DIS 0x00000008 /* RX disabled. */
> +#define XUARTPS_CR_RX_EN 0x00000004 /* RX enabled */
> +#define XUARTPS_CR_TXRST 0x00000002 /* TX logic reset */
> +#define XUARTPS_CR_RXRST 0x00000001 /* RX logic reset */
> +#define XUARTPS_CR_RST_TO 0x00000040 /* Restart Timeout Counter */
> +
> +/** Mode Register
> + *
> + * The mode register (MR) defines the mode of transfer as well as the data
> + * format. If this register is modified during transmission or reception,
> + * data validity cannot be guaranteed.
> + *
> + * Mode Register Bit Definitions
> + *
> + */
> +#define XUARTPS_MR_CLKSEL 0x00000001 /* Pre-scalar selection */
> +#define XUARTPS_MR_CHMODE_L_LOOP 0x00000200 /* Local loop back mode */
> +#define XUARTPS_MR_CHMODE_NORM 0x00000000 /* Normal mode */
> +
> +#define XUARTPS_MR_STOPMODE_2_BIT 0x00000080 /* 2 stop bits */
> +#define XUARTPS_MR_STOPMODE_1_BIT 0x00000000 /* 1 stop bit */
> +
> +#define XUARTPS_MR_PARITY_NONE 0x00000020 /* No parity mode */
> +#define XUARTPS_MR_PARITY_MARK 0x00000018 /* Mark parity mode */
> +#define XUARTPS_MR_PARITY_SPACE 0x00000010 /* Space parity mode */
> +#define XUARTPS_MR_PARITY_ODD 0x00000008 /* Odd parity mode */
> +#define XUARTPS_MR_PARITY_EVEN 0x00000000 /* Even parity mode */
> +
> +#define XUARTPS_MR_CHARLEN_6_BIT 0x00000006 /* 6 bits data */
> +#define XUARTPS_MR_CHARLEN_7_BIT 0x00000004 /* 7 bits data */
> +#define XUARTPS_MR_CHARLEN_8_BIT 0x00000000 /* 8 bits data */
> +
> +/** Interrupt Registers
> + *
> + * Interrupt control logic uses the interrupt enable register (IER) and the
> + * interrupt disable register (IDR) to set the value of the bits in the
> + * interrupt mask register (IMR). The IMR determines whether to pass an
> + * interrupt to the interrupt status register (ISR).
> + * Writing a 1 to IER Enables an interrupt, writing a 1 to IDR disables an
> + * interrupt. IMR and ISR are read only, and IER and IDR are write only.
> + * Reading either IER or IDR returns 0x00.
> + *
> + * All four registers have the same bit definitions.
> + */
> +#define XUARTPS_IXR_TOUT 0x00000100 /* RX Timeout error interrupt */
> +#define XUARTPS_IXR_PARITY 0x00000080 /* Parity error interrupt */
> +#define XUARTPS_IXR_FRAMING 0x00000040 /* Framing error interrupt */
> +#define XUARTPS_IXR_OVERRUN 0x00000020 /* Overrun error interrupt */
> +#define XUARTPS_IXR_TXFULL 0x00000010 /* TX FIFO Full interrupt */
> +#define XUARTPS_IXR_TXEMPTY 0x00000008 /* TX FIFO empty interrupt */
> +#define XUARTPS_ISR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt */
> +#define XUARTPS_IXR_RXTRIG 0x00000001 /* RX FIFO trigger interrupt */
> +#define XUARTPS_IXR_RXFULL 0x00000004 /* RX FIFO full interrupt. */
> +#define XUARTPS_IXR_RXEMPTY 0x00000002 /* RX FIFO empty interrupt. */
> +#define XUARTPS_IXR_MASK 0x00001FFF /* Valid bit mask */
> +
> +
> +/** Channel Status Register
> + *
> + * The channel status register (CSR) is provided to enable the control logic
> + * to monitor the status of bits in the channel interrupt status register,
> + * even if these are masked out by the interrupt mask register.
> + */
> +#define XUARTPS_SR_RXEMPTY 0x00000002 /* RX FIFO empty */
> +#define XUARTPS_SR_TXEMPTY 0x00000008 /* TX FIFO empty */
> +#define XUARTPS_SR_TXFULL 0x00000010 /* TX FIFO full */
> +#define XUARTPS_SR_RXTRIG 0x00000001 /* Rx Trigger */
> +
> +

empty line

> +/**
> + * xuartps_isr - Interrupt handler
> + * @irq: Irq number
> + * @dev_id: Id of the port
> + *
> + * Returns IRQHANDLED
> + **/
> +static irqreturn_t xuartps_isr(int irq, void *dev_id)
> +{
> + struct uart_port *port = (struct uart_port *)dev_id;
> + struct tty_struct *tty;
> + unsigned long flags;
> + unsigned int isrstatus, numbytes;
> + unsigned int data;
> + char status = TTY_NORMAL;
> +
> + /* Get the tty which could be NULL so don't assume it's valid */
> + tty = tty_port_tty_get(&port->state->port);
> +
> + spin_lock_irqsave(&port->lock, flags);
> +
> + /* Read the interrupt status register to determine which
> + * interrupt(s) is/are active.
> + */
> + isrstatus = xuartps_readl(XUARTPS_ISR_OFFSET);
> +
> + /* drop byte with parity error if IGNPAR specified */
> + if (isrstatus & port->ignore_status_mask & XUARTPS_IXR_PARITY)
> + isrstatus &= ~(XUARTPS_IXR_RXTRIG | XUARTPS_IXR_TOUT);
> +
> + isrstatus &= port->read_status_mask;
> + isrstatus &= ~port->ignore_status_mask;
> +
> + if ((isrstatus & XUARTPS_IXR_TOUT) ||
> + (isrstatus & XUARTPS_IXR_RXTRIG)) {
> + /* Receive Timeout Interrupt */
> + while ((xuartps_readl(XUARTPS_SR_OFFSET) &
> + XUARTPS_SR_RXEMPTY) != XUARTPS_SR_RXEMPTY) {
> + data = xuartps_readl(XUARTPS_FIFO_OFFSET);
> + port->icount.rx++;
> +
> + if (isrstatus & XUARTPS_IXR_PARITY) {
> + port->icount.parity++;
> + status = TTY_PARITY;
> + } else if (isrstatus & XUARTPS_IXR_FRAMING) {
> + port->icount.frame++;
> + status = TTY_FRAME;
> + } else if (isrstatus & XUARTPS_IXR_OVERRUN)
> + port->icount.overrun++;
> +
> + if (tty)
> + uart_insert_char(port, isrstatus,
> + XUARTPS_IXR_OVERRUN, data,
> + status);
> + }
> + spin_unlock(&port->lock);
> + if (tty)
> + tty_flip_buffer_push(tty);
> + spin_lock(&port->lock);
> + }
> +
> + /* Dispatch an appropriate handler */
> + if ((isrstatus & XUARTPS_IXR_TXEMPTY) == XUARTPS_IXR_TXEMPTY) {
> + if (uart_circ_empty(&port->state->xmit)) {
> + xuartps_writel(XUARTPS_IXR_TXEMPTY,
> + XUARTPS_IDR_OFFSET);
> + } else {
> + numbytes = port->fifosize;
> + /* Break if no more data available in the UART buffer */
> + while (numbytes--) {
> + if (uart_circ_empty(&port->state->xmit))
> + break;
> + /* Get the data from the UART circular buffer
> + * and write it to the xuartps's TX_FIFO
> + * register.
> + */
> + xuartps_writel(
> + port->state->xmit.buf[port->state->xmit.
> + tail], XUARTPS_FIFO_OFFSET);
> +
> + port->icount.tx++;
> +
> + /* Adjust the tail of the UART buffer and wrap
> + * the buffer if it reaches limit.
> + */
> + port->state->xmit.tail =
> + (port->state->xmit.tail + 1) & \
> + (UART_XMIT_SIZE - 1);
> + }
> +
> + if (uart_circ_chars_pending(
> + &port->state->xmit) < WAKEUP_CHARS)
> + uart_write_wakeup(port);
> + }
> + }
> +
> + xuartps_writel(isrstatus, XUARTPS_ISR_OFFSET);
> +
> + /* be sure to release the lock and tty before leaving */
> + spin_unlock_irqrestore(&port->lock, flags);
> + tty_kref_put(tty);
> +
> + return IRQ_HANDLED;
> +}
> +
> +/**
> + * xuartps_set_baud_rate - Calculate and set the baud rate
> + * @port: Handle to the uart port structure
> + * @baud: Baud rate to set
> + *
> + **/
> +static void xuartps_set_baud_rate(struct uart_port *port, unsigned int baud)
> +{
> + unsigned int sel_clk;
> + unsigned int calc_baud;
> + unsigned int brgr_val, brdiv_val;
> + unsigned int bauderror, percent_err = 100;
> +
> + /* Formula to obtain baud rate is
> + * baud_tx/rx rate = sel_clk/CD * (BDIV + 1)
> + * input_clk = (Uart User Defined Clock or Apb Clock)
> + * depends on UCLKEN in MR Reg
> + * sel_clk = input_clk or input_clk/8;
> + * depends on CLKS in MR reg
> + * CD and BDIV depends on values in
> + * baud rate generate register
> + * baud rate clock divisor register
> + */
> + sel_clk = port->uartclk;
> + if (xuartps_readl(XUARTPS_MR_OFFSET) & XUARTPS_MR_CLKSEL)
> + sel_clk = sel_clk / 8;
> +
> + /* Check for the values of baud clk divisor value ranging from 4 to 255
> + * where the percent_err for the given baud rate is acceptable.
> + */
> + for (brdiv_val = 4; brdiv_val < 255; brdiv_val++) {
> +
> + brgr_val = sel_clk / (baud * (brdiv_val + 1));
> + if (brgr_val < 2 || brgr_val > 65535)
> + continue;
> +
> + calc_baud = sel_clk / (brgr_val * (brdiv_val + 1));
> +
> + if (baud > calc_baud)
> + bauderror = baud - calc_baud;
> + else
> + bauderror = calc_baud - baud;
> +
> + percent_err = (bauderror * 100) / baud;
> + if (percent_err < 3)
> + break;
> + }
> +
> + if (percent_err >= 3)
> + dev_err(port->dev, "Error too large, baud rate not set\n");
> + else {
> + /* Set the values for the new baud rate */
> + xuartps_writel(brgr_val, XUARTPS_BAUDGEN_OFFSET);
> + xuartps_writel(brdiv_val, XUARTPS_BAUDDIV_OFFSET);
> +

remove this empty line.

> + }
> +}
> +
> +
> +/*----------------------Uart Operations---------------------------*/
> +
> +/**
> + * xuartps_start_tx - Start transmitting bytes
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_start_tx(struct uart_port *port)
> +{
> + unsigned int status, numbytes = port->fifosize;
> +
> + if (uart_circ_empty(&port->state->xmit) || uart_tx_stopped(port))
> + return;
> +
> + status = xuartps_readl(XUARTPS_CR_OFFSET);
> + /* Set the TX enable bit and clear the TX disable bit to enable the
> + * transmitter.
> + */
> + xuartps_writel((status & ~XUARTPS_CR_TX_DIS) | XUARTPS_CR_TX_EN,
> + XUARTPS_CR_OFFSET);
> +
> + while (numbytes-- && ((xuartps_readl(XUARTPS_SR_OFFSET)
> + & XUARTPS_SR_TXFULL)) != XUARTPS_SR_TXFULL) {
> +
> + /* Break if no more data available in the UART buffer */
> + if (uart_circ_empty(&port->state->xmit))
> + break;
> +
> + /* Get the data from the UART circular buffer and
> + * write it to the xuartps's TX_FIFO register.
> + */
> + xuartps_writel(
> + port->state->xmit.buf[port->state->xmit.tail],
> + XUARTPS_FIFO_OFFSET);
> + port->icount.tx++;
> +
> + /* Adjust the tail of the UART buffer and wrap
> + * the buffer if it reaches limit.
> + */
> + port->state->xmit.tail = (port->state->xmit.tail + 1) &
> + (UART_XMIT_SIZE - 1);
> + }
> +
> + /* Enable the TX Empty interrupt */
> + xuartps_writel(XUARTPS_IXR_TXEMPTY, XUARTPS_IER_OFFSET);
> +
> + if (uart_circ_chars_pending(&port->state->xmit) < WAKEUP_CHARS)
> + uart_write_wakeup(port);
> +

remove this empty line

> +}
> +
> +/**
> + * xuartps_stop_tx - Stop TX
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_stop_tx(struct uart_port *port)
> +{
> + unsigned int regval;
> +
> + regval = xuartps_readl(XUARTPS_CR_OFFSET);
> + regval |= XUARTPS_CR_TX_DIS;
> + /* Disable the transmitter */
> + xuartps_writel(regval, XUARTPS_CR_OFFSET);
> +}
> +
> +/**
> + * xuartps_stop_rx - Stop RX
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_stop_rx(struct uart_port *port)
> +{
> + unsigned int regval;
> +
> + regval = xuartps_readl(XUARTPS_CR_OFFSET);
> + regval |= XUARTPS_CR_RX_DIS;
> + /* Disable the receiver */
> + xuartps_writel(regval, XUARTPS_CR_OFFSET);
> +}
> +
> +/**
> + * xuartps_tx_empty - Check whether TX is empty
> + * @port: Handle to the uart port structure
> + *
> + * Returns TIOCSER_TEMT on success, 0 otherwise
> + **/
> +static unsigned int xuartps_tx_empty(struct uart_port *port)
> +{
> + unsigned int status;
> +
> + status = xuartps_readl(XUARTPS_ISR_OFFSET) & XUARTPS_IXR_TXEMPTY;
> + return status ? TIOCSER_TEMT : 0;
> +

remove this empty line.

> +}
> +
> +

and this

> +/**
> + * xuartps_break_ctl - Based on the input ctl we have to start or stop
> + * transmitting char breaks
> + * @port: Handle to the uart port structure
> + * @ctl: Value based on which start or stop decision is taken
> + *
> + **/
> +static void xuartps_break_ctl(struct uart_port *port, int ctl)
> +{
> + unsigned int status;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&port->lock, flags);
> +
> + status = xuartps_readl(XUARTPS_CR_OFFSET);
> +
> + if (ctl == -1)
> + xuartps_writel(XUARTPS_CR_STARTBRK | status,
> + XUARTPS_CR_OFFSET);
> + else {
> + if ((status & XUARTPS_CR_STOPBRK) == 0)
> + xuartps_writel(XUARTPS_CR_STOPBRK | status,
> + XUARTPS_CR_OFFSET);
> + }
> + spin_unlock_irqrestore(&port->lock, flags);
> +}
> +
> +/**
> + * xuartps_set_termios - termios operations, handling data length, parity,
> + * stop bits, flow control, baud rate
> + * @port: Handle to the uart port structure
> + * @termios: Handle to the input termios structure
> + * @old: Values of the previously saved termios structure
> + *
> + **/
> +static void xuartps_set_termios(struct uart_port *port,
> + struct ktermios *termios, struct ktermios *old)
> +{
> + unsigned int cval = 0;
> + unsigned int baud;
> + unsigned long flags;
> + unsigned int ctrl_reg, mode_reg;
> +
> + spin_lock_irqsave(&port->lock, flags);
> +
> + /* Empty the receive FIFO 1st before making changes */
> + while ((xuartps_readl(XUARTPS_SR_OFFSET) &
> + XUARTPS_SR_RXEMPTY) != XUARTPS_SR_RXEMPTY) {
> + xuartps_readl(XUARTPS_FIFO_OFFSET);
> + }
> +
> + /* Disable the TX and RX to set baud rate */
> + xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
> + (XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS),
> + XUARTPS_CR_OFFSET);
> +
> + /* Min baud rate = 6bps and Max Baud Rate is 10Mbps for 100Mhz clk */
> + baud = uart_get_baud_rate(port, termios, old, 0, 10000000);
> + xuartps_set_baud_rate(port, baud);
> + if (tty_termios_baud_rate(termios))
> + tty_termios_encode_baud_rate(termios, baud, baud);
> +
> + /*
> + * Update the per-port timeout.
> + */
> + uart_update_timeout(port, termios->c_cflag, baud);
> +
> + /* Set TX/RX Reset */
> + xuartps_writel(xuartps_readl(XUARTPS_CR_OFFSET) |
> + (XUARTPS_CR_TXRST | XUARTPS_CR_RXRST),
> + XUARTPS_CR_OFFSET);
> +
> + ctrl_reg = xuartps_readl(XUARTPS_CR_OFFSET);
> +
> + /* Clear the RX disable and TX disable bits and then set the TX enable
> + * bit and RX enable bit to enable the transmitter and receiver.
> + */
> + xuartps_writel(
> + (ctrl_reg & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS))
> + | (XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN),
> + XUARTPS_CR_OFFSET);
> +
> + xuartps_writel(10, XUARTPS_RXTOUT_OFFSET);
> +
> + port->read_status_mask = XUARTPS_IXR_TXEMPTY | XUARTPS_IXR_RXTRIG |
> + XUARTPS_IXR_OVERRUN | XUARTPS_IXR_TOUT;
> + port->ignore_status_mask = 0;
> +
> + if (termios->c_iflag & INPCK)
> + port->read_status_mask |= XUARTPS_IXR_PARITY |
> + XUARTPS_IXR_FRAMING;
> +
> + if (termios->c_iflag & IGNPAR)
> + port->ignore_status_mask |= XUARTPS_IXR_PARITY |
> + XUARTPS_IXR_FRAMING | XUARTPS_IXR_OVERRUN;
> +
> + /* ignore all characters if CREAD is not set */
> + if ((termios->c_cflag & CREAD) == 0)
> + port->ignore_status_mask |= XUARTPS_IXR_RXTRIG |
> + XUARTPS_IXR_TOUT | XUARTPS_IXR_PARITY |
> + XUARTPS_IXR_FRAMING | XUARTPS_IXR_OVERRUN;
> +
> + mode_reg = xuartps_readl(XUARTPS_MR_OFFSET);
> +
> + /* Handling Data Size */
> + switch (termios->c_cflag & CSIZE) {
> + case CS6:
> + cval |= XUARTPS_MR_CHARLEN_6_BIT;
> + break;
> + case CS7:
> + cval |= XUARTPS_MR_CHARLEN_7_BIT;
> + break;
> + default:
> + case CS8:
> + cval |= XUARTPS_MR_CHARLEN_8_BIT;
> + termios->c_cflag &= ~CSIZE;
> + termios->c_cflag |= CS8;
> + break;
> + }
> +
> + /* Handling Parity and Stop Bits length */
> + if (termios->c_cflag & CSTOPB)
> + cval |= XUARTPS_MR_STOPMODE_2_BIT; /* 2 STOP bits */
> + else
> + cval |= XUARTPS_MR_STOPMODE_1_BIT; /* 1 STOP bit */
> +
> + if (termios->c_cflag & PARENB) {
> + /* Mark or Space parity */
> + if (termios->c_cflag & CMSPAR) {
> + if (termios->c_cflag & PARODD)
> + cval |= XUARTPS_MR_PARITY_MARK;
> + else
> + cval |= XUARTPS_MR_PARITY_SPACE;
> + } else if (termios->c_cflag & PARODD)
> + cval |= XUARTPS_MR_PARITY_ODD;
> + else
> + cval |= XUARTPS_MR_PARITY_EVEN;
> + } else
> + cval |= XUARTPS_MR_PARITY_NONE;
> + xuartps_writel(cval , XUARTPS_MR_OFFSET);
> +
> + spin_unlock_irqrestore(&port->lock, flags);
> +}
> +
> +/**
> + * xuartps_startup - Called when an application opens a xuartps port
> + * @port: Handle to the uart port structure
> + *
> + * Returns 0 on success, negative error otherwise
> + **/
> +static int xuartps_startup(struct uart_port *port)
> +{
> + unsigned int retval = 0, status = 0;
> +
> + retval = request_irq(port->irq, xuartps_isr, 0, XUARTPS_NAME,
> + (void *)port);
> + if (retval)
> + return retval;
> +
> + /* Disable the TX and RX */
> + xuartps_writel(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS,
> + XUARTPS_CR_OFFSET);
> +
> + /* Set the Control Register with TX/RX Enable, TX/RX Reset,
> + * no break chars.
> + */
> + xuartps_writel(XUARTPS_CR_TXRST | XUARTPS_CR_RXRST,
> + XUARTPS_CR_OFFSET);
> +
> + status = xuartps_readl(XUARTPS_CR_OFFSET);
> +
> + /* Clear the RX disable and TX disable bits and then set the TX enable
> + * bit and RX enable bit to enable the transmitter and receiver.
> + */
> + xuartps_writel((status & ~(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS))
> + | (XUARTPS_CR_TX_EN | XUARTPS_CR_RX_EN |
> + XUARTPS_CR_STOPBRK), XUARTPS_CR_OFFSET);
> +
> + /* Set the Mode Register with normal mode,8 data bits,1 stop bit,
> + * no parity.
> + */
> + xuartps_writel(XUARTPS_MR_CHMODE_NORM | XUARTPS_MR_STOPMODE_1_BIT
> + | XUARTPS_MR_PARITY_NONE | XUARTPS_MR_CHARLEN_8_BIT,
> + XUARTPS_MR_OFFSET);
> +
> + /* Set the RX FIFO Trigger level to 14 assuming FIFO size as 16 */
> + xuartps_writel(14, XUARTPS_RXWM_OFFSET);
> +
> + /* Receive Timeout register is enabled with value of 10 */
> + xuartps_writel(10, XUARTPS_RXTOUT_OFFSET);
> +
> +
> + /* Set the Interrupt Registers with desired interrupts */
> + xuartps_writel(XUARTPS_IXR_TXEMPTY | XUARTPS_IXR_PARITY |
> + XUARTPS_IXR_FRAMING | XUARTPS_IXR_OVERRUN |
> + XUARTPS_IXR_RXTRIG | XUARTPS_IXR_TOUT, XUARTPS_IER_OFFSET);
> + xuartps_writel(~(XUARTPS_IXR_TXEMPTY | XUARTPS_IXR_PARITY |
> + XUARTPS_IXR_FRAMING | XUARTPS_IXR_OVERRUN |
> + XUARTPS_IXR_RXTRIG | XUARTPS_IXR_TOUT), XUARTPS_IDR_OFFSET);
> +
> + return retval;
> +}
> +
> +/**
> + * xuartps_shutdown - Called when an application closes a xuartps port
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_shutdown(struct uart_port *port)
> +{
> + int status;
> +
> + /* Disable interrupts */
> + status = xuartps_readl(XUARTPS_IMR_OFFSET);
> + xuartps_writel(status, XUARTPS_IDR_OFFSET);
> +
> + /* Disable the TX and RX */
> + xuartps_writel(XUARTPS_CR_TX_DIS | XUARTPS_CR_RX_DIS,
> + XUARTPS_CR_OFFSET);
> + free_irq(port->irq, port);
> +}
> +
> +/**
> + * xuartps_type - Set UART type to xuartps port
> + * @port: Handle to the uart port structure
> + *
> + * Returns string on success, NULL otherwise
> + **/
> +static const char *xuartps_type(struct uart_port *port)
> +{
> + return port->type == PORT_XUARTPS ? XUARTPS_NAME : NULL;
> +}
> +
> +/**
> + * xuartps_verify_port - Verify the port params
> + * @port: Handle to the uart port structure
> + * @ser: Handle to the structure whose members are compared
> + *
> + * Returns 0 if success otherwise -EINVAL
> + **/
> +static int xuartps_verify_port(struct uart_port *port,
> + struct serial_struct *ser)
> +{
> + if (ser->type != PORT_UNKNOWN && ser->type != PORT_XUARTPS)
> + return -EINVAL;
> + if (port->irq != ser->irq)
> + return -EINVAL;
> + if (ser->io_type != UPIO_MEM)
> + return -EINVAL;
> + if (port->iobase != ser->port)
> + return -EINVAL;
> + if (ser->hub6 != 0)
> + return -EINVAL;
> + return 0;
> +}
> +
> +/**
> + * xuartps_request_port - Claim the memory region attached to xuartps port,
> + * called when the driver adds a xuartps port via
> + * uart_add_one_port()
> + * @port: Handle to the uart port structure
> + *
> + * Returns 0, -ENOMEM if request fails
> + **/
> +static int xuartps_request_port(struct uart_port *port)
> +{
> + if (!request_mem_region(port->mapbase, XUARTPS_REGISTER_SPACE,
> + XUARTPS_NAME)) {
> + return -ENOMEM;
> + }
> +
> + port->membase = ioremap(port->mapbase, XUARTPS_REGISTER_SPACE);
> + if (!port->membase) {
> + dev_err(port->dev, "Unable to map registers\n");
> + release_mem_region(port->mapbase, XUARTPS_REGISTER_SPACE);
> + return -ENOMEM;
> + }
> + return 0;
> +}
> +
> +/**
> + * xuartps_release_port - Release the memory region attached to a xuartps
> + * port, called when the driver removes a xuartps
> + * port via uart_remove_one_port().
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_release_port(struct uart_port *port)
> +{
> + release_mem_region(port->mapbase, XUARTPS_REGISTER_SPACE);
> + iounmap(port->membase);
> + port->membase = NULL;
> +}
> +
> +/**
> + * xuartps_config_port - Configure xuartps, called when the driver adds a
> + * xuartps port
> + * @port: Handle to the uart port structure
> + * @flags: If any
> + *
> + **/
> +static void xuartps_config_port(struct uart_port *port, int flags)
> +{
> + if (flags & UART_CONFIG_TYPE && xuartps_request_port(port) == 0)
> + port->type = PORT_XUARTPS;
> +

empty line

> +}
> +
> +/**
> + * xuartps_get_mctrl - Get the modem control state
> + *
> + * @port: Handle to the uart port structure
> + *
> + * Returns the modem control state
> + *
> + **/
> +static unsigned int xuartps_get_mctrl(struct uart_port *port)
> +{
> + return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
> +}
> +
> +static void xuartps_set_mctrl(struct uart_port *port, unsigned int mctrl)
> +{
> + /* N/A */
> +}
> +
> +static void xuartps_enable_ms(struct uart_port *port)
> +{
> + /* N/A */
> +}
> +
> +/** The UART operations structure
> + */
> +static struct uart_ops xuartps_ops = {
> + .set_mctrl = xuartps_set_mctrl,
> + .get_mctrl = xuartps_get_mctrl,
> + .enable_ms = xuartps_enable_ms,
> +
> + .start_tx = xuartps_start_tx, /* Start transmitting */
> + .stop_tx = xuartps_stop_tx, /* Stop transmission */
> + .stop_rx = xuartps_stop_rx, /* Stop reception */
> + .tx_empty = xuartps_tx_empty, /* Transmitter busy? */
> + .break_ctl = xuartps_break_ctl, /* Start/stop
> + * transmitting break
> + */
> + .set_termios = xuartps_set_termios, /* Set termios */
> + .startup = xuartps_startup, /* App opens xuartps */
> + .shutdown = xuartps_shutdown, /* App closes xuartps */
> + .type = xuartps_type, /* Set UART type */
> + .verify_port = xuartps_verify_port, /* Verification of port
> + * params
> + */
> + .request_port = xuartps_request_port, /* Claim resources
> + * associated with a
> + * xuartps port
> + */
> + .release_port = xuartps_release_port, /* Release resources
> + * associated with a
> + * xuartps port
> + */
> + .config_port = xuartps_config_port, /* Configure when driver
> + * adds a xuartps port
> + */
> +};
> +
> +static struct uart_port xuartps_port[2];
> +
> +/**
> + * xuartps_get_port - Configure the port from the platform device resource
> + * info
> + *
> + * Returns a pointer to a uart_port or NULL for failure
> + **/
> +static struct uart_port *xuartps_get_port(void)
> +{
> + struct uart_port *port;
> + int id;
> +
> + /* Find the next unused port */
> + for (id = 0; id < XUARTPS_NR_PORTS; id++)
> + if (xuartps_port[id].mapbase == 0)
> + break;
> +
> + if (id >= XUARTPS_NR_PORTS)
> + return NULL;
> +
> + port = &xuartps_port[id];
> +
> + /* At this point, we've got an empty uart_port struct, initialize it */
> + spin_lock_init(&port->lock);
> + port->membase = NULL;
> + port->iobase = 1; /* mark port in use */
> + port->irq = NO_IRQ;
> + port->type = PORT_UNKNOWN;
> + port->iotype = UPIO_MEM32;
> + port->flags = UPF_BOOT_AUTOCONF;
> + port->ops = &xuartps_ops;
> + port->fifosize = XUARTPS_FIFO_SIZE;
> + port->line = id;
> + port->dev = NULL;
> + return port;
> +}
> +
> +/*-----------------------Console driver operations--------------------------*/
> +
> +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
> +/**
> + * xuartps_console_wait_tx - Wait for the TX to be full
> + * @port: Handle to the uart port structure
> + *
> + **/
> +static void xuartps_console_wait_tx(struct uart_port *port)
> +{
> + while ((xuartps_readl(XUARTPS_SR_OFFSET) & XUARTPS_SR_TXEMPTY)
> + != XUARTPS_SR_TXEMPTY)
> + barrier();
> +}
> +
> +/**
> + * xuartps_console_putchar - write the character to the FIFO buffer
> + * @port: Handle to the uart port structure
> + * @ch: Character to be written
> + *
> + **/
> +static void xuartps_console_putchar(struct uart_port *port, int ch)
> +{
> + xuartps_console_wait_tx(port);
> + xuartps_writel(ch, XUARTPS_FIFO_OFFSET);
> +}
> +
> +/**
> + * xuartps_console_write - perform write operation
> + * @port: Handle to the uart port structure
> + * @s: Pointer to character array
> + * @count: No of characters
> + **/
> +static void xuartps_console_write(struct console *co, const char *s,
> + unsigned int count)
> +{
> + struct uart_port *port = &xuartps_port[co->index];
> + unsigned long flags;
> + unsigned int imr;
> + int locked = 1;
> +
> + if (oops_in_progress)
> + locked = spin_trylock_irqsave(&port->lock, flags);
> + else
> + spin_lock_irqsave(&port->lock, flags);
> +
> + /* save and disable interrupt */
> + imr = xuartps_readl(XUARTPS_IMR_OFFSET);
> + xuartps_writel(imr, XUARTPS_IDR_OFFSET);
> +
> + uart_console_write(port, s, count, xuartps_console_putchar);
> + xuartps_console_wait_tx(port);
> +
> + /* restore interrupt state, it seems like there may be a h/w bug
> + * in that the interrupt enable register should not need to be
> + * written based on the data sheet
> + */
> + xuartps_writel(~imr, XUARTPS_IDR_OFFSET);
> + xuartps_writel(imr, XUARTPS_IER_OFFSET);
> +
> + if (locked)
> + spin_unlock_irqrestore(&port->lock, flags);
> +}
> +
> +/**
> + * xuartps_console_setup - Initialize the uart to default config
> + * @co: Console handle
> + * @options: Initial settings of uart
> + *
> + * Returns 0, -ENODEV if no device
> + **/
> +static int __init xuartps_console_setup(struct console *co, char *options)
> +{
> + struct uart_port *port = &xuartps_port[co->index];
> + int baud = 9600;
> + int bits = 8;
> + int parity = 'n';
> + int flow = 'n';
> +
> + if (co->index < 0 || co->index >= XUARTPS_NR_PORTS)
> + return -EINVAL;
> +
> + if (!port->mapbase) {
> + pr_debug("console on ttyPS%i not present\n", co->index);
> + return -ENODEV;
> + }
> +
> + if (options)
> + uart_parse_options(options, &baud, &parity, &bits, &flow);
> +
> + return uart_set_options(port, co, baud, parity, bits, flow);
> +}
> +
> +static struct uart_driver xuartps_uart_driver;
> +
> +static struct console xuartps_console = {
> + .name = XUARTPS_TTY_NAME,
> + .write = xuartps_console_write,
> + .device = uart_console_device,
> + .setup = xuartps_console_setup,
> + .flags = CON_PRINTBUFFER,
> + .index = -1, /* Specified on the cmdline (e.g. console=ttyPS ) */
> + .data = &xuartps_uart_driver,
> +};
> +
> +/**
> + * xuartps_console_init - Initialization call
> + *
> + * Returns 0 on success, negative error otherwise
> + **/
> +static int __init xuartps_console_init(void)
> +{
> + register_console(&xuartps_console);
> + return 0;
> +}
> +
> +console_initcall(xuartps_console_init);
> +
> +#endif /* CONFIG_SERIAL_XILINX_PS_UART_CONSOLE */
> +
> +/** Structure Definitions
> + */
> +static struct uart_driver xuartps_uart_driver = {
> + .owner = THIS_MODULE, /* Owner */
> + .driver_name = XUARTPS_NAME, /* Driver name */
> + .dev_name = XUARTPS_TTY_NAME, /* Node name */
> + .major = XUARTPS_MAJOR, /* Major number */
> + .minor = XUARTPS_MINOR, /* Minor number */
> + .nr = XUARTPS_NR_PORTS, /* Number of UART ports */
> +#ifdef CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
> + .cons = &xuartps_console, /* Console */
> +#endif
> +};
> +
> +/* ---------------------------------------------------------------------
> + * Platform bus binding
> + */
> +/**
> + * xuartps_probe - Platform driver probe
> + * @pdev: Pointer to the platform device structure
> + *
> + * Returns 0 on success, negative error otherwise
> + **/
> +static int __devinit xuartps_probe(struct platform_device *pdev)
> +{
> + int rc;
> + struct uart_port *port;
> + struct resource *res, *res2;
> + int clk = 0;
> +
> +#ifdef CONFIG_OF
> + const unsigned int *prop;
> +
> + prop = of_get_property(pdev->dev.of_node, "clock", NULL);
> + if (prop)
> + clk = be32_to_cpup(prop);
> +#else
> + clk = *((unsigned int *)(pdev->dev.platform_data));
> +#endif
> + if (!clk) {
> + dev_err(&pdev->dev, "no clock specified\n");
> + return -ENODEV;
> + }
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENODEV;
> +
> + res2 = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> + if (!res2)
> + return -ENODEV;
> +
> + /* Initialize the port structure */
> + port = xuartps_get_port();
> +
> + if (!port) {
> + dev_err(&pdev->dev, "Cannot get uart_port structure\n");
> + return -ENODEV;
> + } else {
> + /* Register the port.
> + * This function also registers this device with the tty layer
> + * and triggers invocation of the config_port() entry point.
> + */
> + port->mapbase = res->start;
> + port->irq = res2->start;
> + port->dev = &pdev->dev;
> + port->uartclk = clk;
> + dev_set_drvdata(&pdev->dev, port);
> + rc = uart_add_one_port(&xuartps_uart_driver, port);
> + if (rc) {
> + dev_err(&pdev->dev, "uart_add_one_port() failed; \
> + err=%i\n", rc);
> + dev_set_drvdata(&pdev->dev, NULL);
> + return rc;
> + }
> + return 0;
> + }
> +}
> +
> +/**
> + * xuartps_remove - called when the platform driver is unregistered
> + * @pdev: Pointer to the platform device structure
> + *
> + * Returns 0 on success, negative error otherwise
> + **/
> +static int __devexit xuartps_remove(struct platform_device *pdev)
> +{
> + struct uart_port *port = dev_get_drvdata(&pdev->dev);
> + int rc = 0;
> +
> + /* Remove the xuartps port from the serial core */
> + if (port) {
> + rc = uart_remove_one_port(&xuartps_uart_driver, port);
> + dev_set_drvdata(&pdev->dev, NULL);
> + port->mapbase = 0;
> + }
> + return rc;
> +}
> +
> +/**
> + * xuartps_suspend - suspend event
> + * @pdev: Pointer to the platform device structure
> + * @state: State of the device
> + *
> + * Returns 0
> + **/
> +static int xuartps_suspend(struct platform_device *pdev, pm_message_t state)
> +{
> + /* Call the API provided in serial_core.c file which handles
> + * the suspend.
> + */
> + uart_suspend_port(&xuartps_uart_driver, &xuartps_port[pdev->id]);
> + return 0;
> +}
> +
> +/**
> + * xuartps_resume - Resume after a previous suspend
> + * @pdev: Pointer to the platform device structure
> + *
> + * Returns 0
> + **/
> +static int xuartps_resume(struct platform_device *pdev)
> +{
> + uart_resume_port(&xuartps_uart_driver, &xuartps_port[pdev->id]);
> + return 0;
> +}
> +
> +/* Match table for of_platform binding */
> +
> +#ifdef CONFIG_OF
> +static struct of_device_id xuartps_of_match[] __devinitdata = {
> + { .compatible = "xlnx,xuartps", },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, xuartps_of_match);
> +#endif
> +
> +static struct platform_driver xuartps_platform_driver = {
> + .probe = xuartps_probe, /* Probe method */
> + .remove = __exit_p(xuartps_remove), /* Detach method */
> + .suspend = xuartps_suspend, /* Suspend */
> + .resume = xuartps_resume, /* Resume after a suspend */
> + .driver = {
> + .owner = THIS_MODULE,
> + .name = XUARTPS_NAME, /* Driver name */
> +#ifdef CONFIG_OF
> + .of_match_table = xuartps_of_match,
> +#endif
> + },
> +};

AFAIK. Grant proposed to write it in different style. I think he will agree with me.

#ifdef CONFIG_OF
static struct of_device_id xuartps_of_match[] __devinitdata = {
{ .compatible = "xlnx,xuartps", },
{}
};
MODULE_DEVICE_TABLE(of, xuartps_of_match);
#else
#define xuartps_of_match NULL
#endif

static struct platform_driver xuartps_platform_driver = {
.probe = xuartps_probe, /* Probe method */
.remove = __exit_p(xuartps_remove), /* Detach method */
.suspend = xuartps_suspend, /* Suspend */
.resume = xuartps_resume, /* Resume after a suspend */
.driver = {
.owner = THIS_MODULE,
.name = XUARTPS_NAME, /* Driver name */
.of_match_table = xuartps_of_match,
},
};

Regards,
Michal

--
Michal Simek, Ing. (M.Eng)
PetaLogix - Linux Solutions for a Reconfigurable World
w: www.petalogix.com p: +61-7-30090663,+42-0-721842854 f: +61-7-30090663