of_serial.c

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/*
 *  Serial Port driver for Open Firmware platform devices
 *
 *    Copyright (C) 2006 Arnd Bergmann <[email protected]>, IBM Corp.
 *
 *  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/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/serial_core.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_serial.h>
#include <linux/of_platform.h>
#include <linux/nwpserial.h>

struct of_serial_info {
    int type;
    int line;
};

#ifdef CONFIG_ARCH_TEGRA
void tegra_serial_handle_break(struct uart_port *p)
{
    unsigned int status, tmout = 10000;

    do {
        status = p->serial_in(p, UART_LSR);
        if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
            status = p->serial_in(p, UART_RX);
        else
            break;
        if (--tmout == 0)
            break;
        udelay(1);
    } while (1);
}
/* FIXME remove this export when tegra finishes conversion to open firmware */
EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
#endif

/*
 * Fill a struct uart_port for a given device node
 */
static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
                    int type, struct uart_port *port)
{
    struct resource resource;
    struct device_node *np = ofdev->dev.of_node;
    u32 clk, spd, prop;
    int ret;

    memset(port, 0, sizeof *port);
    if (of_property_read_u32(np, "clock-frequency", &clk)) {
        dev_warn(&ofdev->dev, "no clock-frequency property set\n");
        return -ENODEV;
    }
    /* If current-speed was set, then try not to change it. */
    if (of_property_read_u32(np, "current-speed", &spd) == 0)
        port->custom_divisor = clk / (16 * spd);

    ret = of_address_to_resource(np, 0, &resource);
    if (ret) {
        dev_warn(&ofdev->dev, "invalid address\n");
        return ret;
    }

    spin_lock_init(&port->lock);
    port->mapbase = resource.start;

    /* Check for shifted address mapping */
    if (of_property_read_u32(np, "reg-offset", &prop) == 0)
        port->mapbase += prop;

    /* Check for registers offset within the devices address range */
    if (of_property_read_u32(np, "reg-shift", &prop) == 0)
        port->regshift = prop;

    port->irq = irq_of_parse_and_map(np, 0);
    port->iotype = UPIO_MEM;
    if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
        switch (prop) {
        case 1:
            port->iotype = UPIO_MEM;
            break;
        case 4:
            port->iotype = UPIO_MEM32;
            break;
        default:
            dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
                 prop);
            return -EINVAL;
        }
    }

    port->type = type;
    port->uartclk = clk;
    port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
        | UPF_FIXED_PORT | UPF_FIXED_TYPE;

    if (of_find_property(np, "no-loopback-test", NULL))
        port->flags |= UPF_SKIP_TEST;

    port->dev = &ofdev->dev;

    if (type == PORT_TEGRA)
        port->handle_break = tegra_serial_handle_break;

    return 0;
}

/*
 * Try to register a serial port
 */
static struct of_device_id of_platform_serial_table[];
static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
{
    const struct of_device_id *match;
    struct of_serial_info *info;
    struct uart_port port;
    int port_type;
    int ret;

    match = of_match_device(of_platform_serial_table, &ofdev->dev);
    if (!match)
        return -EINVAL;

    if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
        return -EBUSY;

    info = kmalloc(sizeof(*info), GFP_KERNEL);
    if (info == NULL)
        return -ENOMEM;

    port_type = (unsigned long)match->data;
    ret = of_platform_serial_setup(ofdev, port_type, &port);
    if (ret)
        goto out;

    switch (port_type) {
#ifdef CONFIG_SERIAL_8250
    case PORT_8250 ... PORT_MAX_8250:
    {
        /* For now the of bindings don't support the extra
           8250 specific bits */
        struct uart_8250_port port8250;
        memset(&port8250, 0, sizeof(port8250));
        port8250.port = port;
        ret = serial8250_register_8250_port(&port8250);
        break;
    }
#endif
#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
    case PORT_NWPSERIAL:
        ret = nwpserial_register_port(&port);
        break;
#endif
    default:
        /* need to add code for these */
    case PORT_UNKNOWN:
        dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
        ret = -ENODEV;
        break;
    }
    if (ret < 0)
        goto out;

    info->type = port_type;
    info->line = ret;
    dev_set_drvdata(&ofdev->dev, info);
    return 0;
out:
    kfree(info);
    irq_dispose_mapping(port.irq);
    return ret;
}

/*
 * Release a line
 */
static int of_platform_serial_remove(struct platform_device *ofdev)
{
    struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
    switch (info->type) {
#ifdef CONFIG_SERIAL_8250
    case PORT_8250 ... PORT_MAX_8250:
        serial8250_unregister_port(info->line);
        break;
#endif
#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
    case PORT_NWPSERIAL:
        nwpserial_unregister_port(info->line);
        break;
#endif
    default:
        /* need to add code for these */
        break;
    }
    kfree(info);
    return 0;
}

/*
 * A few common types, add more as needed.
 */
static struct of_device_id __devinitdata of_platform_serial_table[] = {
    { .compatible = "ns8250",   .data = (void *)PORT_8250, },
    { .compatible = "ns16450",  .data = (void *)PORT_16450, },
    { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
    { .compatible = "ns16550",  .data = (void *)PORT_16550, },
    { .compatible = "ns16750",  .data = (void *)PORT_16750, },
    { .compatible = "ns16850",  .data = (void *)PORT_16850, },
    { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
    { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
    { .compatible = "ibm,qpace-nwp-serial",
        .data = (void *)PORT_NWPSERIAL, },
#endif
    { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
    { /* end of list */ },
};

static struct platform_driver of_platform_serial_driver = {
    .driver = {
        .name = "of_serial",
        .owner = THIS_MODULE,
        .of_match_table = of_platform_serial_table,
    },
    .probe = of_platform_serial_probe,
    .remove = of_platform_serial_remove,
};

module_platform_driver(of_platform_serial_driver);

MODULE_AUTHOR("Arnd Bergmann <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");