1 files changed, 477 insertions, 0 deletions

diff --git a/drivers/tty/serial/nwpserial.c b/drivers/tty/serial/nwpserial.c
new file mode 100644
index 000000000000..de173671e3d0
--- /dev/null
+++ b/drivers/tty/serial/nwpserial.c
@@ -0,0 +1,477 @@
+/*
+ *  Serial Port driver for a NWP uart device
+ *
+ *    Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
+ *
+ *  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/init.h>
+#include <linux/console.h>
+#include <linux/serial.h>
+#include <linux/serial_reg.h>
+#include <linux/serial_core.h>
+#include <linux/tty.h>
+#include <linux/irqreturn.h>
+#include <linux/mutex.h>
+#include <linux/of_platform.h>
+#include <linux/of_device.h>
+#include <linux/nwpserial.h>
+#include <asm/prom.h>
+#include <asm/dcr.h>
+
+#define NWPSERIAL_NR               2
+
+#define NWPSERIAL_STATUS_RXVALID 0x1
+#define NWPSERIAL_STATUS_TXFULL  0x2
+
+struct nwpserial_port {
+        struct uart_port port;
+        dcr_host_t dcr_host;
+        unsigned int ier;
+        unsigned int mcr;
+};
+
+static DEFINE_MUTEX(nwpserial_mutex);
+static struct nwpserial_port nwpserial_ports[NWPSERIAL_NR];
+
+static void wait_for_bits(struct nwpserial_port *up, int bits)
+{
+        unsigned int status, tmout = 10000;
+
+        /* Wait up to 10ms for the character(s) to be sent. */
+        do {
+                status = dcr_read(up->dcr_host, UART_LSR);
+
+                if (--tmout == 0)
+                        break;
+                udelay(1);
+        } while ((status & bits) != bits);
+}
+
+#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
+static void nwpserial_console_putchar(struct uart_port *port, int c)
+{
+        struct nwpserial_port *up;
+        up = container_of(port, struct nwpserial_port, port);
+        /* check if tx buffer is full */
+        wait_for_bits(up, UART_LSR_THRE);
+        dcr_write(up->dcr_host, UART_TX, c);
+        up->port.icount.tx++;
+}
+
+static void
+nwpserial_console_write(struct console *co, const char *s, unsigned int count)
+{
+        struct nwpserial_port *up = &nwpserial_ports[co->index];
+        unsigned long flags;
+        int locked = 1;
+
+        if (oops_in_progress)
+                locked = spin_trylock_irqsave(&up->port.lock, flags);
+        else
+                spin_lock_irqsave(&up->port.lock, flags);
+
+        /* save and disable interrupt */
+        up->ier = dcr_read(up->dcr_host, UART_IER);
+        dcr_write(up->dcr_host, UART_IER, up->ier & ~UART_IER_RDI);
+
+        uart_console_write(&up->port, s, count, nwpserial_console_putchar);
+
+        /* wait for transmitter to become empty */
+        while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
+                cpu_relax();
+
+        /* restore interrupt state */
+        dcr_write(up->dcr_host, UART_IER, up->ier);
+
+        if (locked)
+                spin_unlock_irqrestore(&up->port.lock, flags);
+}
+
+static struct uart_driver nwpserial_reg;
+static struct console nwpserial_console = {
+        .name           = "ttySQ",
+        .write          = nwpserial_console_write,
+        .device         = uart_console_device,
+        .flags          = CON_PRINTBUFFER,
+        .index          = -1,
+        .data           = &nwpserial_reg,
+};
+#define NWPSERIAL_CONSOLE       (&nwpserial_console)
+#else
+#define NWPSERIAL_CONSOLE       NULL
+#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */
+
+/**************************************************************************/
+
+static int nwpserial_request_port(struct uart_port *port)
+{
+        return 0;
+}
+
+static void nwpserial_release_port(struct uart_port *port)
+{
+        /* N/A */
+}
+
+static void nwpserial_config_port(struct uart_port *port, int flags)
+{
+        port->type = PORT_NWPSERIAL;
+}
+
+static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
+{
+        struct nwpserial_port *up = dev_id;
+        struct tty_struct *tty = up->port.state->port.tty;
+        irqreturn_t ret;
+        unsigned int iir;
+        unsigned char ch;
+
+        spin_lock(&up->port.lock);
+
+        /* check if the uart was the interrupt source. */
+        iir = dcr_read(up->dcr_host, UART_IIR);
+        if (!iir) {
+                ret = IRQ_NONE;
+                goto out;
+        }
+
+        do {
+                up->port.icount.rx++;
+                ch = dcr_read(up->dcr_host, UART_RX);
+                if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
+                        tty_insert_flip_char(tty, ch, TTY_NORMAL);
+        } while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);
+
+        tty_flip_buffer_push(tty);
+        ret = IRQ_HANDLED;
+
+        /* clear interrupt */
+        dcr_write(up->dcr_host, UART_IIR, 1);
+out:
+        spin_unlock(&up->port.lock);
+        return ret;
+}
+
+static int nwpserial_startup(struct uart_port *port)
+{
+        struct nwpserial_port *up;
+        int err;
+
+        up = container_of(port, struct nwpserial_port, port);
+
+        /* disable flow control by default */
+        up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
+        dcr_write(up->dcr_host, UART_MCR, up->mcr);
+
+        /* register interrupt handler */
+        err = request_irq(up->port.irq, nwpserial_interrupt,
+                        IRQF_SHARED, "nwpserial", up);
+        if (err)
+                return err;
+
+        /* enable interrupts */
+        up->ier = UART_IER_RDI;
+        dcr_write(up->dcr_host, UART_IER, up->ier);
+
+        /* enable receiving */
+        up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;
+
+        return 0;
+}
+
+static void nwpserial_shutdown(struct uart_port *port)
+{
+        struct nwpserial_port *up;
+        up = container_of(port, struct nwpserial_port, port);
+
+        /* disable receiving */
+        up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
+
+        /* disable interrupts from this port */
+        up->ier = 0;
+        dcr_write(up->dcr_host, UART_IER, up->ier);
+
+        /* free irq */
+        free_irq(up->port.irq, port);
+}
+
+static int nwpserial_verify_port(struct uart_port *port,
+                        struct serial_struct *ser)
+{
+        return -EINVAL;
+}
+
+static const char *nwpserial_type(struct uart_port *port)
+{
+        return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
+}
+
+static void nwpserial_set_termios(struct uart_port *port,
+                        struct ktermios *termios, struct ktermios *old)
+{
+        struct nwpserial_port *up;
+        up = container_of(port, struct nwpserial_port, port);
+
+        up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID
+                                | NWPSERIAL_STATUS_TXFULL;
+
+        up->port.ignore_status_mask = 0;
+        /* ignore all characters if CREAD is not set */
+        if ((termios->c_cflag & CREAD) == 0)
+                up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;
+
+        /* Copy back the old hardware settings */
+        if (old)
+                tty_termios_copy_hw(termios, old);
+}
+
+static void nwpserial_break_ctl(struct uart_port *port, int ctl)
+{
+        /* N/A */
+}
+
+static void nwpserial_enable_ms(struct uart_port *port)
+{
+        /* N/A */
+}
+
+static void nwpserial_stop_rx(struct uart_port *port)
+{
+        struct nwpserial_port *up;
+        up = container_of(port, struct nwpserial_port, port);
+        /* don't forward any more data (like !CREAD) */
+        up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
+}
+
+static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
+{
+        /* check if tx buffer is full */
+        wait_for_bits(up, UART_LSR_THRE);
+        dcr_write(up->dcr_host, UART_TX, c);
+        up->port.icount.tx++;
+}
+
+static void nwpserial_start_tx(struct uart_port *port)
+{
+        struct nwpserial_port *up;
+        struct circ_buf *xmit;
+        up = container_of(port, struct nwpserial_port, port);
+        xmit  = &up->port.state->xmit;
+
+        if (port->x_char) {
+                nwpserial_putchar(up, up->port.x_char);
+                port->x_char = 0;
+        }
+
+        while (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port))) {
+                nwpserial_putchar(up, xmit->buf[xmit->tail]);
+                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
+        }
+}
+
+static unsigned int nwpserial_get_mctrl(struct uart_port *port)
+{
+        return 0;
+}
+
+static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+        /* N/A */
+}
+
+static void nwpserial_stop_tx(struct uart_port *port)
+{
+        /* N/A */
+}
+
+static unsigned int nwpserial_tx_empty(struct uart_port *port)
+{
+        struct nwpserial_port *up;
+        unsigned long flags;
+        int ret;
+        up = container_of(port, struct nwpserial_port, port);
+
+        spin_lock_irqsave(&up->port.lock, flags);
+        ret = dcr_read(up->dcr_host, UART_LSR);
+        spin_unlock_irqrestore(&up->port.lock, flags);
+
+        return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
+}
+
+static struct uart_ops nwpserial_pops = {
+        .tx_empty     = nwpserial_tx_empty,
+        .set_mctrl    = nwpserial_set_mctrl,
+        .get_mctrl    = nwpserial_get_mctrl,
+        .stop_tx      = nwpserial_stop_tx,
+        .start_tx     = nwpserial_start_tx,
+        .stop_rx      = nwpserial_stop_rx,
+        .enable_ms    = nwpserial_enable_ms,
+        .break_ctl    = nwpserial_break_ctl,
+        .startup      = nwpserial_startup,
+        .shutdown     = nwpserial_shutdown,
+        .set_termios  = nwpserial_set_termios,
+        .type         = nwpserial_type,
+        .release_port = nwpserial_release_port,
+        .request_port = nwpserial_request_port,
+        .config_port  = nwpserial_config_port,
+        .verify_port  = nwpserial_verify_port,
+};
+
+static struct uart_driver nwpserial_reg = {
+        .owner       = THIS_MODULE,
+        .driver_name = "nwpserial",
+        .dev_name    = "ttySQ",
+        .major       = TTY_MAJOR,
+        .minor       = 68,
+        .nr          = NWPSERIAL_NR,
+        .cons        = NWPSERIAL_CONSOLE,
+};
+
+int nwpserial_register_port(struct uart_port *port)
+{
+        struct nwpserial_port *up = NULL;
+        int ret = -1;
+        int i;
+        static int first = 1;
+        int dcr_len;
+        int dcr_base;
+        struct device_node *dn;
+
+        mutex_lock(&nwpserial_mutex);
+
+        dn = port->dev->of_node;
+        if (dn == NULL)
+                goto out;
+
+        /* get dcr base. */
+        dcr_base = dcr_resource_start(dn, 0);
+
+        /* find matching entry */
+        for (i = 0; i < NWPSERIAL_NR; i++)
+                if (nwpserial_ports[i].port.iobase == dcr_base) {
+                        up = &nwpserial_ports[i];
+                        break;
+                }
+
+        /* we didn't find a mtching entry, search for a free port */
+        if (up == NULL)
+                for (i = 0; i < NWPSERIAL_NR; i++)
+                        if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
+                                nwpserial_ports[i].port.iobase == 0) {
+                                up = &nwpserial_ports[i];
+                                break;
+                        }
+
+        if (up == NULL) {
+                ret = -EBUSY;
+                goto out;
+        }
+
+        if (first)
+                uart_register_driver(&nwpserial_reg);
+        first = 0;
+
+        up->port.membase      = port->membase;
+        up->port.irq          = port->irq;
+        up->port.uartclk      = port->uartclk;
+        up->port.fifosize     = port->fifosize;
+        up->port.regshift     = port->regshift;
+        up->port.iotype       = port->iotype;
+        up->port.flags        = port->flags;
+        up->port.mapbase      = port->mapbase;
+        up->port.private_data = port->private_data;
+
+        if (port->dev)
+                up->port.dev = port->dev;
+
+        if (up->port.iobase != dcr_base) {
+                up->port.ops          = &nwpserial_pops;
+                up->port.fifosize     = 16;
+
+                spin_lock_init(&up->port.lock);
+
+                up->port.iobase = dcr_base;
+                dcr_len = dcr_resource_len(dn, 0);
+
+                up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
+                if (!DCR_MAP_OK(up->dcr_host)) {
+                        printk(KERN_ERR "Cannot map DCR resources for NWPSERIAL");
+                        goto out;
+                }
+        }
+
+        ret = uart_add_one_port(&nwpserial_reg, &up->port);
+        if (ret == 0)
+                ret = up->port.line;
+
+out:
+        mutex_unlock(&nwpserial_mutex);
+
+        return ret;
+}
+EXPORT_SYMBOL(nwpserial_register_port);
+
+void nwpserial_unregister_port(int line)
+{
+        struct nwpserial_port *up = &nwpserial_ports[line];
+        mutex_lock(&nwpserial_mutex);
+        uart_remove_one_port(&nwpserial_reg, &up->port);
+
+        up->port.type = PORT_UNKNOWN;
+
+        mutex_unlock(&nwpserial_mutex);
+}
+EXPORT_SYMBOL(nwpserial_unregister_port);
+
+#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
+static int __init nwpserial_console_init(void)
+{
+        struct nwpserial_port *up = NULL;
+        struct device_node *dn;
+        const char *name;
+        int dcr_base;
+        int dcr_len;
+        int i;
+
+        /* search for a free port */
+        for (i = 0; i < NWPSERIAL_NR; i++)
+                if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
+                        up = &nwpserial_ports[i];
+                        break;
+                }
+
+        if (up == NULL)
+                return -1;
+
+        name = of_get_property(of_chosen, "linux,stdout-path", NULL);
+        if (name == NULL)
+                return -1;
+
+        dn = of_find_node_by_path(name);
+        if (!dn)
+                return -1;
+
+        spin_lock_init(&up->port.lock);
+        up->port.ops = &nwpserial_pops;
+        up->port.type = PORT_NWPSERIAL;
+        up->port.fifosize = 16;
+
+        dcr_base = dcr_resource_start(dn, 0);
+        dcr_len = dcr_resource_len(dn, 0);
+        up->port.iobase = dcr_base;
+
+        up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
+        if (!DCR_MAP_OK(up->dcr_host)) {
+                printk("Cannot map DCR resources for SERIAL");
+                return -1;
+        }
+        register_console(&nwpserial_console);
+        return 0;
+}
+console_initcall(nwpserial_console_init);
+#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */