linux/drivers/serial/of_serial.c
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   1/*
   2 *  Serial Port driver for Open Firmware platform devices
   3 *
   4 *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
   5 *
   6 *  This program is free software; you can redistribute it and/or
   7 *  modify it under the terms of the GNU General Public License
   8 *  as published by the Free Software Foundation; either version
   9 *  2 of the License, or (at your option) any later version.
  10 *
  11 */
  12#include <linux/init.h>
  13#include <linux/module.h>
  14#include <linux/serial_core.h>
  15#include <linux/serial_8250.h>
  16#include <linux/of_platform.h>
  17#include <linux/nwpserial.h>
  18
  19#include <asm/prom.h>
  20
  21struct of_serial_info {
  22        int type;
  23        int line;
  24};
  25
  26/*
  27 * Fill a struct uart_port for a given device node
  28 */
  29static int __devinit of_platform_serial_setup(struct of_device *ofdev,
  30                                        int type, struct uart_port *port)
  31{
  32        struct resource resource;
  33        struct device_node *np = ofdev->node;
  34        const unsigned int *clk, *spd;
  35        const u32 *prop;
  36        int ret, prop_size;
  37
  38        memset(port, 0, sizeof *port);
  39        spd = of_get_property(np, "current-speed", NULL);
  40        clk = of_get_property(np, "clock-frequency", NULL);
  41        if (!clk) {
  42                dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  43                return -ENODEV;
  44        }
  45
  46        ret = of_address_to_resource(np, 0, &resource);
  47        if (ret) {
  48                dev_warn(&ofdev->dev, "invalid address\n");
  49                return ret;
  50        }
  51
  52        spin_lock_init(&port->lock);
  53        port->mapbase = resource.start;
  54
  55        /* Check for shifted address mapping */
  56        prop = of_get_property(np, "reg-offset", &prop_size);
  57        if (prop && (prop_size == sizeof(u32)))
  58                port->mapbase += *prop;
  59
  60        /* Check for registers offset within the devices address range */
  61        prop = of_get_property(np, "reg-shift", &prop_size);
  62        if (prop && (prop_size == sizeof(u32)))
  63                port->regshift = *prop;
  64
  65        port->irq = irq_of_parse_and_map(np, 0);
  66        port->iotype = UPIO_MEM;
  67        port->type = type;
  68        port->uartclk = *clk;
  69        port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  70                | UPF_FIXED_PORT | UPF_FIXED_TYPE;
  71        port->dev = &ofdev->dev;
  72        /* If current-speed was set, then try not to change it. */
  73        if (spd)
  74                port->custom_divisor = *clk / (16 * (*spd));
  75
  76        return 0;
  77}
  78
  79/*
  80 * Try to register a serial port
  81 */
  82static int __devinit of_platform_serial_probe(struct of_device *ofdev,
  83                                                const struct of_device_id *id)
  84{
  85        struct of_serial_info *info;
  86        struct uart_port port;
  87        int port_type;
  88        int ret;
  89
  90        if (of_find_property(ofdev->node, "used-by-rtas", NULL))
  91                return -EBUSY;
  92
  93        info = kmalloc(sizeof(*info), GFP_KERNEL);
  94        if (info == NULL)
  95                return -ENOMEM;
  96
  97        port_type = (unsigned long)id->data;
  98        ret = of_platform_serial_setup(ofdev, port_type, &port);
  99        if (ret)
 100                goto out;
 101
 102        switch (port_type) {
 103#ifdef CONFIG_SERIAL_8250
 104        case PORT_8250 ... PORT_MAX_8250:
 105                ret = serial8250_register_port(&port);
 106                break;
 107#endif
 108#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 109        case PORT_NWPSERIAL:
 110                ret = nwpserial_register_port(&port);
 111                break;
 112#endif
 113        default:
 114                /* need to add code for these */
 115        case PORT_UNKNOWN:
 116                dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 117                ret = -ENODEV;
 118                break;
 119        }
 120        if (ret < 0)
 121                goto out;
 122
 123        info->type = port_type;
 124        info->line = ret;
 125        dev_set_drvdata(&ofdev->dev, info);
 126        return 0;
 127out:
 128        kfree(info);
 129        irq_dispose_mapping(port.irq);
 130        return ret;
 131}
 132
 133/*
 134 * Release a line
 135 */
 136static int of_platform_serial_remove(struct of_device *ofdev)
 137{
 138        struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 139        switch (info->type) {
 140#ifdef CONFIG_SERIAL_8250
 141        case PORT_8250 ... PORT_MAX_8250:
 142                serial8250_unregister_port(info->line);
 143                break;
 144#endif
 145#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 146        case PORT_NWPSERIAL:
 147                nwpserial_unregister_port(info->line);
 148                break;
 149#endif
 150        default:
 151                /* need to add code for these */
 152                break;
 153        }
 154        kfree(info);
 155        return 0;
 156}
 157
 158/*
 159 * A few common types, add more as needed.
 160 */
 161static struct of_device_id __devinitdata of_platform_serial_table[] = {
 162        { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
 163        { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
 164        { .type = "serial", .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 165        { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
 166        { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
 167        { .type = "serial", .compatible = "ns16850",  .data = (void *)PORT_16850, },
 168#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 169        { .type = "serial", .compatible = "ibm,qpace-nwp-serial",
 170                                        .data = (void *)PORT_NWPSERIAL, },
 171#endif
 172        { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
 173        { /* end of list */ },
 174};
 175
 176static struct of_platform_driver of_platform_serial_driver = {
 177        .owner = THIS_MODULE,
 178        .name = "of_serial",
 179        .probe = of_platform_serial_probe,
 180        .remove = of_platform_serial_remove,
 181        .match_table = of_platform_serial_table,
 182};
 183
 184static int __init of_platform_serial_init(void)
 185{
 186        return of_register_platform_driver(&of_platform_serial_driver);
 187}
 188module_init(of_platform_serial_init);
 189
 190static void __exit of_platform_serial_exit(void)
 191{
 192        return of_unregister_platform_driver(&of_platform_serial_driver);
 193};
 194module_exit(of_platform_serial_exit);
 195
 196MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 197MODULE_LICENSE("GPL");
 198MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
 199