[ARM] 4332/2: KS8695: Serial driver

A driver for the KS8695 internal UART.

Based on the 2.6.9 driver from Micrel.

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

3 files changed, 675 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index a6f5bfbb777b..315ea9916456 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -359,6 +359,23 @@ config SERIAL_ATMEL_TTYAT
 
           Say Y if you have an external 8250/16C550 UART.  If unsure, say N.
 
+config SERIAL_KS8695
+        bool "Micrel KS8695 (Centaur) serial port support"
+        depends on ARCH_KS8695
+        select SERIAL_CORE
+        help
+          This selects the Micrel Centaur KS8695 UART.  Say Y here.
+
+config SERIAL_KS8695_CONSOLE
+        bool "Support for console on KS8695 (Centaur) serial port"
+        depends on SERIAL_KS8695=y
+        select SERIAL_CORE_CONSOLE
+        help
+          Say Y here if you wish to use a KS8695 (Centaur) UART as the
+          system console (the system console is the device which
+          receives all kernel messages and warnings and which allows
+          logins in single user mode).
+
 config SERIAL_CLPS711X
         tristate "CLPS711X serial port support"
         depends on ARM && ARCH_CLPS711X
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 4959bcb8d1ef..08ad0d978183 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -61,3 +61,4 @@ obj-$(CONFIG_SERIAL_ATMEL) += atmel_serial.o
 obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o
 obj-$(CONFIG_SERIAL_NETX) += netx-serial.o
 obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o
+obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o
diff --git a/drivers/serial/serial_ks8695.c b/drivers/serial/serial_ks8695.c
new file mode 100644
index 000000000000..c5346d677315
--- /dev/null
+++ b/drivers/serial/serial_ks8695.c
@@ -0,0 +1,657 @@
+/*
+ *  drivers/serial/serial_ks8695.c
+ *
+ *  Driver for KS8695 serial ports
+ *
+ *  Based on drivers/serial/serial_amba.c, by Kam Lee.
+ *
+ *  Copyright 2002-2005 Micrel Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/serial.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/device.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/mach/irq.h>
+
+#include <asm/arch/regs-uart.h>
+#include <asm/arch/regs-irq.h>
+
+#if defined(CONFIG_SERIAL_KS8695_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
+#define SUPPORT_SYSRQ
+#endif
+
+#include <linux/serial_core.h>
+
+
+#define SERIAL_KS8695_MAJOR     204
+#define SERIAL_KS8695_MINOR     16
+#define SERIAL_KS8695_DEVNAME   "ttyAM"
+
+#define SERIAL_KS8695_NR        1
+
+/*
+ * Access macros for the KS8695 UART
+ */
+#define UART_GET_CHAR(p)        (__raw_readl((p)->membase + KS8695_URRB) & 0xFF)
+#define UART_PUT_CHAR(p, c)     __raw_writel((c), (p)->membase + KS8695_URTH)
+#define UART_GET_FCR(p)         __raw_readl((p)->membase + KS8695_URFC)
+#define UART_PUT_FCR(p, c)      __raw_writel((c), (p)->membase + KS8695_URFC)
+#define UART_GET_MSR(p)         __raw_readl((p)->membase + KS8695_URMS)
+#define UART_GET_LSR(p)         __raw_readl((p)->membase + KS8695_URLS)
+#define UART_GET_LCR(p)         __raw_readl((p)->membase + KS8695_URLC)
+#define UART_PUT_LCR(p, c)      __raw_writel((c), (p)->membase + KS8695_URLC)
+#define UART_GET_MCR(p)         __raw_readl((p)->membase + KS8695_URMC)
+#define UART_PUT_MCR(p, c)      __raw_writel((c), (p)->membase + KS8695_URMC)
+#define UART_GET_BRDR(p)        __raw_readl((p)->membase + KS8695_URBD)
+#define UART_PUT_BRDR(p, c)     __raw_writel((c), (p)->membase + KS8695_URBD)
+
+#define KS8695_CLR_TX_INT()     __raw_writel(1 << KS8695_IRQ_UART_TX, KS8695_IRQ_VA + KS8695_INTST)
+
+#define UART_DUMMY_LSR_RX       0x100
+#define UART_PORT_SIZE          (KS8695_USR - KS8695_URRB + 4)
+
+#define tx_enabled(port) ((port)->unused[0])
+#define rx_enabled(port) ((port)->unused[1])
+
+
+#ifdef SUPPORT_SYSRQ
+static struct console ks8695_console;
+#endif
+
+static void ks8695uart_stop_tx(struct uart_port *port)
+{
+        if (tx_enabled(port)) {
+                disable_irq(KS8695_IRQ_UART_TX);
+                tx_enabled(port) = 0;
+        }
+}
+
+static void ks8695uart_start_tx(struct uart_port *port)
+{
+        if (!tx_enabled(port)) {
+                enable_irq(KS8695_IRQ_UART_TX);
+                tx_enabled(port) = 1;
+        }
+}
+
+static void ks8695uart_stop_rx(struct uart_port *port)
+{
+        if (rx_enabled(port)) {
+                disable_irq(KS8695_IRQ_UART_RX);
+                rx_enabled(port) = 0;
+        }
+}
+
+static void ks8695uart_enable_ms(struct uart_port *port)
+{
+        enable_irq(KS8695_IRQ_UART_MODEM_STATUS);
+}
+
+static void ks8695uart_disable_ms(struct uart_port *port)
+{
+        disable_irq(KS8695_IRQ_UART_MODEM_STATUS);
+}
+
+static irqreturn_t ks8695uart_rx_chars(int irq, void *dev_id)
+{
+        struct uart_port *port = dev_id;
+        struct tty_struct *tty = port->info->tty;
+        unsigned int status, ch, lsr, flg, max_count = 256;
+
+        status = UART_GET_LSR(port);            /* clears pending LSR interrupts */
+        while ((status & URLS_URDR) && max_count--) {
+                ch = UART_GET_CHAR(port);
+                flg = TTY_NORMAL;
+
+                port->icount.rx++;
+
+                /*
+                 * Note that the error handling code is
+                 * out of the main execution path
+                 */
+                lsr = UART_GET_LSR(port) | UART_DUMMY_LSR_RX;
+                if (unlikely(lsr & (URLS_URBI | URLS_URPE | URLS_URFE | URLS_URROE))) {
+                        if (lsr & URLS_URBI) {
+                                lsr &= ~(URLS_URFE | URLS_URPE);
+                                port->icount.brk++;
+                                if (uart_handle_break(port))
+                                        goto ignore_char;
+                        }
+                        if (lsr & URLS_URPE)
+                                port->icount.parity++;
+                        if (lsr & URLS_URFE)
+                                port->icount.frame++;
+                        if (lsr & URLS_URROE)
+                                port->icount.overrun++;
+
+                        lsr &= port->read_status_mask;
+
+                        if (lsr & URLS_URBI)
+                                flg = TTY_BREAK;
+                        else if (lsr & URLS_URPE)
+                                flg = TTY_PARITY;
+                        else if (lsr & URLS_URFE)
+                                flg = TTY_FRAME;
+                }
+
+                if (uart_handle_sysrq_char(port, ch))
+                        goto ignore_char;
+
+                uart_insert_char(port, lsr, URLS_URROE, ch, flg);
+
+ignore_char:
+                status = UART_GET_LSR(port);
+        }
+        tty_flip_buffer_push(tty);
+
+        return IRQ_HANDLED;
+}
+
+
+static irqreturn_t ks8695uart_tx_chars(int irq, void *dev_id)
+{
+        struct uart_port *port = dev_id;
+        struct circ_buf *xmit = &port->info->xmit;
+        unsigned int count;
+
+        if (port->x_char) {
+                KS8695_CLR_TX_INT();
+                UART_PUT_CHAR(port, port->x_char);
+                port->icount.tx++;
+                port->x_char = 0;
+                return IRQ_HANDLED;
+        }
+
+        if (uart_tx_stopped(port) || uart_circ_empty(xmit)) {
+                ks8695uart_stop_tx(port);
+                return IRQ_HANDLED;
+        }
+
+        count = 16;     /* fifo size */
+        while (!uart_circ_empty(xmit) && (count-- > 0)) {
+                KS8695_CLR_TX_INT();
+                UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
+
+                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+                port->icount.tx++;
+        }
+
+        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+                uart_write_wakeup(port);
+
+        if (uart_circ_empty(xmit))
+                ks8695uart_stop_tx(port);
+
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t ks8695uart_modem_status(int irq, void *dev_id)
+{
+        struct uart_port *port = dev_id;
+        unsigned int status;
+
+        /*
+         * clear modem interrupt by reading MSR
+         */
+        status = UART_GET_MSR(port);
+
+        if (status & URMS_URDDCD)
+                uart_handle_dcd_change(port, status & URMS_URDDCD);
+
+        if (status & URMS_URDDST)
+                port->icount.dsr++;
+
+        if (status & URMS_URDCTS)
+                uart_handle_cts_change(port, status & URMS_URDCTS);
+
+        if (status & URMS_URTERI)
+                port->icount.rng++;
+
+        wake_up_interruptible(&port->info->delta_msr_wait);
+
+        return IRQ_HANDLED;
+}
+
+static unsigned int ks8695uart_tx_empty(struct uart_port *port)
+{
+        return (UART_GET_LSR(port) & URLS_URTE) ? TIOCSER_TEMT : 0;
+}
+
+static unsigned int ks8695uart_get_mctrl(struct uart_port *port)
+{
+        unsigned int result = 0;
+        unsigned int status;
+
+        status = UART_GET_MSR(port);
+        if (status & URMS_URDCD)
+                result |= TIOCM_CAR;
+        if (status & URMS_URDSR)
+                result |= TIOCM_DSR;
+        if (status & URMS_URCTS)
+                result |= TIOCM_CTS;
+        if (status & URMS_URRI)
+                result |= TIOCM_RI;
+
+        return result;
+}
+
+static void ks8695uart_set_mctrl(struct uart_port *port, u_int mctrl)
+{
+        unsigned int mcr;
+
+        mcr = UART_GET_MCR(port);
+        if (mctrl & TIOCM_RTS)
+                mcr |= URMC_URRTS;
+        else
+                mcr &= ~URMC_URRTS;
+
+        if (mctrl & TIOCM_DTR)
+                mcr |= URMC_URDTR;
+        else
+                mcr &= ~URMC_URDTR;
+
+        UART_PUT_MCR(port, mcr);
+}
+
+static void ks8695uart_break_ctl(struct uart_port *port, int break_state)
+{
+        unsigned int lcr;
+
+        lcr = UART_GET_LCR(port);
+
+        if (break_state == -1)
+                lcr |= URLC_URSBC;
+        else
+                lcr &= ~URLC_URSBC;
+
+        UART_PUT_LCR(port, lcr);
+}
+
+static int ks8695uart_startup(struct uart_port *port)
+{
+        int retval;
+
+        set_irq_flags(KS8695_IRQ_UART_TX, IRQF_VALID | IRQF_NOAUTOEN);
+        tx_enabled(port) = 0;
+        rx_enabled(port) = 1;
+
+        /*
+         * Allocate the IRQ
+         */
+        retval = request_irq(KS8695_IRQ_UART_TX, ks8695uart_tx_chars, IRQF_DISABLED, "UART TX", port);
+        if (retval)
+                goto err_tx;
+
+        retval = request_irq(KS8695_IRQ_UART_RX, ks8695uart_rx_chars, IRQF_DISABLED, "UART RX", port);
+        if (retval)
+                goto err_rx;
+
+        retval = request_irq(KS8695_IRQ_UART_LINE_STATUS, ks8695uart_rx_chars, IRQF_DISABLED, "UART LineStatus", port);
+        if (retval)
+                return err_ls;
+
+        retval = request_irq(KS8695_IRQ_UART_MODEM_STATUS, ks8695uart_modem_status, IRQF_DISABLED, "UART ModemStatus", port);
+        if (retval)
+                return err_ms;
+
+        return 0;
+
+err_ms:
+        free_irq(KS8695_IRQ_UART_LINE_STATUS, port);
+err_ls:
+        free_irq(KS8695_IRQ_UART_RX, port);
+err_rx:
+        free_irq(KS8695_IRQ_UART_TX, port);
+err_tx:
+        return retval;
+}
+
+static void ks8695uart_shutdown(struct uart_port *port)
+{
+        /*
+         * Free the interrupt
+         */
+        free_irq(KS8695_IRQ_UART_RX, port);
+        free_irq(KS8695_IRQ_UART_TX, port);
+        free_irq(KS8695_IRQ_UART_MODEM_STATUS, port);
+        free_irq(KS8695_IRQ_UART_LINE_STATUS, port);
+
+        /* disable break condition and fifos */
+        UART_PUT_LCR(port, UART_GET_LCR(port) & ~URLC_URSBC);
+        UART_PUT_FCR(port, UART_GET_FCR(port) & ~URFC_URFE);
+}
+
+static void ks8695uart_set_termios(struct uart_port *port, struct ktermios *termios, struct ktermios *old)
+{
+        unsigned int lcr, fcr = 0;
+        unsigned long flags;
+        unsigned int baud, quot;
+
+        /*
+         * Ask the core to calculate the divisor for us.
+         */
+        baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
+        quot = uart_get_divisor(port, baud);
+
+        switch (termios->c_cflag & CSIZE) {
+        case CS5:
+                lcr = URCL_5;
+                break;
+        case CS6:
+                lcr = URCL_6;
+                break;
+        case CS7:
+                lcr = URCL_7;
+                break;
+        default:
+                lcr = URCL_8;
+                break;
+        }
+
+        /* stop bits */
+        if (termios->c_cflag & CSTOPB)
+                lcr |= URLC_URSB;
+
+        /* parity */
+        if (termios->c_cflag & PARENB) {
+                if (termios->c_cflag & CMSPAR) {        /* Mark or Space parity */
+                        if (termios->c_cflag & PARODD)
+                                lcr |= URPE_MARK;
+                        else
+                                lcr |= URPE_SPACE;
+                }
+                else if (termios->c_cflag & PARODD)
+                        lcr |= URPE_ODD;
+                else
+                        lcr |= URPE_EVEN;
+        }
+
+        if (port->fifosize > 1)
+                fcr = URFC_URFRT_8 | URFC_URTFR | URFC_URRFR | URFC_URFE;
+
+        spin_lock_irqsave(&port->lock, flags);
+
+        /*
+         * Update the per-port timeout.
+         */
+        uart_update_timeout(port, termios->c_cflag, baud);
+
+        port->read_status_mask = URLS_URROE;
+        if (termios->c_iflag & INPCK)
+                port->read_status_mask |= (URLS_URFE | URLS_URPE);
+        if (termios->c_iflag & (BRKINT | PARMRK))
+                port->read_status_mask |= URLS_URBI;
+
+        /*
+         * Characters to ignore
+         */
+        port->ignore_status_mask = 0;
+        if (termios->c_iflag & IGNPAR)
+                port->ignore_status_mask |= (URLS_URFE | URLS_URPE);
+        if (termios->c_iflag & IGNBRK) {
+                port->ignore_status_mask |= URLS_URBI;
+                /*
+                 * If we're ignoring parity and break indicators,
+                 * ignore overruns too (for real raw support).
+                 */
+                if (termios->c_iflag & IGNPAR)
+                        port->ignore_status_mask |= URLS_URROE;
+        }
+
+        /*
+         * Ignore all characters if CREAD is not set.
+         */
+        if ((termios->c_cflag & CREAD) == 0)
+                port->ignore_status_mask |= UART_DUMMY_LSR_RX;
+
+        /* first, disable everything */
+        if (UART_ENABLE_MS(port, termios->c_cflag))
+                ks8695uart_enable_ms(port);
+        else
+                ks8695uart_disable_ms(port);
+
+        /* Set baud rate */
+        UART_PUT_BRDR(port, quot);
+
+        UART_PUT_LCR(port, lcr);
+        UART_PUT_FCR(port, fcr);
+
+        spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static const char *ks8695uart_type(struct uart_port *port)
+{
+        return port->type == PORT_KS8695 ? "KS8695" : NULL;
+}
+
+/*
+ * Release the memory region(s) being used by 'port'
+ */
+static void ks8695uart_release_port(struct uart_port *port)
+{
+        release_mem_region(port->mapbase, UART_PORT_SIZE);
+}
+
+/*
+ * Request the memory region(s) being used by 'port'
+ */
+static int ks8695uart_request_port(struct uart_port *port)
+{
+        return request_mem_region(port->mapbase, UART_PORT_SIZE,
+                        "serial_ks8695") != NULL ? 0 : -EBUSY;
+}
+
+/*
+ * Configure/autoconfigure the port.
+ */
+static void ks8695uart_config_port(struct uart_port *port, int flags)
+{
+        if (flags & UART_CONFIG_TYPE) {
+                port->type = PORT_KS8695;
+                ks8695uart_request_port(port);
+        }
+}
+
+/*
+ * verify the new serial_struct (for TIOCSSERIAL).
+ */
+static int ks8695uart_verify_port(struct uart_port *port, struct serial_struct *ser)
+{
+        int ret = 0;
+
+        if (ser->type != PORT_UNKNOWN && ser->type != PORT_KS8695)
+                ret = -EINVAL;
+        if (ser->irq != port->irq)
+                ret = -EINVAL;
+        if (ser->baud_base < 9600)
+                ret = -EINVAL;
+        return ret;
+}
+
+static struct uart_ops ks8695uart_pops = {
+        .tx_empty       = ks8695uart_tx_empty,
+        .set_mctrl      = ks8695uart_set_mctrl,
+        .get_mctrl      = ks8695uart_get_mctrl,
+        .stop_tx        = ks8695uart_stop_tx,
+        .start_tx       = ks8695uart_start_tx,
+        .stop_rx        = ks8695uart_stop_rx,
+        .enable_ms      = ks8695uart_enable_ms,
+        .break_ctl      = ks8695uart_break_ctl,
+        .startup        = ks8695uart_startup,
+        .shutdown       = ks8695uart_shutdown,
+        .set_termios    = ks8695uart_set_termios,
+        .type           = ks8695uart_type,
+        .release_port   = ks8695uart_release_port,
+        .request_port   = ks8695uart_request_port,
+        .config_port    = ks8695uart_config_port,
+        .verify_port    = ks8695uart_verify_port,
+};
+
+static struct uart_port ks8695uart_ports[SERIAL_KS8695_NR] = {
+        {
+                .membase        = (void *) KS8695_UART_VA,
+                .mapbase        = KS8695_UART_VA,
+                .iotype         = SERIAL_IO_MEM,
+                .irq            = KS8695_IRQ_UART_TX,
+                .uartclk        = CLOCK_TICK_RATE * 16,
+                .fifosize       = 16,
+                .ops            = &ks8695uart_pops,
+                .flags          = ASYNC_BOOT_AUTOCONF,
+                .line           = 0,
+        }
+};
+
+#ifdef CONFIG_SERIAL_KS8695_CONSOLE
+static void ks8695_console_putchar(struct uart_port *port, int ch)
+{
+        while (!(UART_GET_LSR(port) & URLS_URTHRE))
+                barrier();
+
+        UART_PUT_CHAR(port, ch);
+}
+
+static void ks8695_console_write(struct console *co, const char *s, u_int count)
+{
+        struct uart_port *port = ks8695uart_ports + co->index;
+
+        uart_console_write(port, s, count, ks8695_console_putchar);
+}
+
+static void __init ks8695_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits)
+{
+        unsigned int lcr;
+
+        lcr = UART_GET_LCR(port);
+
+        switch (lcr & URLC_PARITY) {
+                case URPE_ODD:
+                        *parity = 'o';
+                        break;
+                case URPE_EVEN:
+                        *parity = 'e';
+                        break;
+                default:
+                        *parity = 'n';
+        }
+
+        switch (lcr & URLC_URCL) {
+                case URCL_5:
+                        *bits = 5;
+                        break;
+                case URCL_6:
+                        *bits = 6;
+                        break;
+                case URCL_7:
+                        *bits = 7;
+                        break;
+                default:
+                        *bits = 8;
+        }
+
+        *baud = port->uartclk / (UART_GET_BRDR(port) & 0x0FFF);
+        *baud /= 16;
+        *baud &= 0xFFFFFFF0;
+}
+
+static int __init ks8695_console_setup(struct console *co, char *options)
+{
+        struct uart_port *port;
+        int baud = 115200;
+        int bits = 8;
+        int parity = 'n';
+        int flow = 'n';
+
+        /*
+         * Check whether an invalid uart number has been specified, and
+         * if so, search for the first available port that does have
+         * console support.
+         */
+        port = uart_get_console(ks8695uart_ports, SERIAL_KS8695_NR, co);
+
+        if (options)
+                uart_parse_options(options, &baud, &parity, &bits, &flow);
+        else
+                ks8695_console_get_options(port, &baud, &parity, &bits);
+
+        return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+extern struct uart_driver ks8695_reg;
+
+static struct console ks8695_console = {
+        .name           = SERIAL_KS8695_DEVNAME,
+        .write          = ks8695_console_write,
+        .device         = uart_console_device,
+        .setup          = ks8695_console_setup,
+        .flags          = CON_PRINTBUFFER,
+        .index          = -1,
+        .data           = &ks8695_reg,
+};
+
+static int __init ks8695_console_init(void)
+{
+        register_console(&ks8695_console);
+        return 0;
+}
+
+console_initcall(ks8695_console_init);
+
+#define KS8695_CONSOLE  &ks8695_console
+#else
+#define KS8695_CONSOLE  NULL
+#endif
+
+static struct uart_driver ks8695_reg = {
+        .owner                  = THIS_MODULE,
+        .driver_name            = "serial_ks8695",
+        .dev_name               = SERIAL_KS8695_DEVNAME,
+        .major                  = SERIAL_KS8695_MAJOR,
+        .minor                  = SERIAL_KS8695_MINOR,
+        .nr                     = SERIAL_KS8695_NR,
+        .cons                   = KS8695_CONSOLE,
+};
+
+static int __init ks8695uart_init(void)
+{
+        int i, ret;
+
+        printk(KERN_INFO "Serial: Micrel KS8695 UART driver\n");
+
+        ret = uart_register_driver(&ks8695_reg);
+        if (ret)
+                return ret;
+
+        for (i = 0; i < SERIAL_KS8695_NR; i++)
+                uart_add_one_port(&ks8695_reg, &ks8695uart_ports[0]);
+
+        return 0;
+}
+
+static void __exit ks8695uart_exit(void)
+{
+        int i;
+
+        for (i = 0; i < SERIAL_KS8695_NR; i++)
+                uart_remove_one_port(&ks8695_reg, &ks8695uart_ports[0]);
+        uart_unregister_driver(&ks8695_reg);
+}
+
+module_init(ks8695uart_init);
+module_exit(ks8695uart_exit);
+
+MODULE_DESCRIPTION("KS8695 serial port driver");
+MODULE_AUTHOR("Micrel Inc.");
+MODULE_LICENSE("GPL");