drivers/serial/of_serial.c

   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
  21 struct of_serial_info {
  22         int type;
  23         int line;
  24 };
  25
  26 /*
  27  * Fill a struct uart_port for a given device node
  28  */
  29 static 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;
  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  */
  82 static 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         ofdev->dev.driver_data = info;
 126         return 0;
 127 out:
 128         kfree(info);
 129         irq_dispose_mapping(port.irq);
 130         return ret;
 131 }
 132
 133 /*
 134  * Release a line
 135  */
 136 static int of_platform_serial_remove(struct of_device *ofdev)
 137 {
 138         struct of_serial_info *info = ofdev->dev.driver_data;
 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  */
 161 static 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 = "ns16550",  .data = (void *)PORT_16550, },
 165         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
 166         { .type = "serial", .compatible = "ns16850",  .data = (void *)PORT_16850, },
 167 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 168         { .type = "serial", .compatible = "ibm,qpace-nwp-serial",
 169                                         .data = (void *)PORT_NWPSERIAL, },
 170 #endif
 171         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
 172         { /* end of list */ },
 173 };
 174
 175 static struct of_platform_driver of_platform_serial_driver = {
 176         .owner = THIS_MODULE,
 177         .name = "of_serial",
 178         .probe = of_platform_serial_probe,
 179         .remove = of_platform_serial_remove,
 180         .match_table = of_platform_serial_table,
 181 };
 182
 183 static int __init of_platform_serial_init(void)
 184 {
 185         return of_register_platform_driver(&of_platform_serial_driver);
 186 }
 187 module_init(of_platform_serial_init);
 188
 189 static void __exit of_platform_serial_exit(void)
 190 {
 191         return of_unregister_platform_driver(&of_platform_serial_driver);
 192 };
 193 module_exit(of_platform_serial_exit);
 194
 195 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 196 MODULE_LICENSE("GPL");
 197 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");