drivers/tty/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/slab.h>
  15 #include <linux/serial_core.h>
  16 #include <linux/serial_8250.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/nwpserial.h>
  21
  22 struct of_serial_info {
  23         int type;
  24         int line;
  25 };
  26
  27 /*
  28  * Fill a struct uart_port for a given device node
  29  */
  30 static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
  31                                         int type, struct uart_port *port)
  32 {
  33         struct resource resource;
  34         struct device_node *np = ofdev->dev.of_node;
  35         u32 clk, spd, prop;
  36         int ret;
  37
  38         memset(port, 0, sizeof *port);
  39         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  40                 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  41                 return -ENODEV;
  42         }
  43         /* If current-speed was set, then try not to change it. */
  44         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  45                 port->custom_divisor = clk / (16 * spd);
  46
  47         ret = of_address_to_resource(np, 0, &resource);
  48         if (ret) {
  49                 dev_warn(&ofdev->dev, "invalid address\n");
  50                 return ret;
  51         }
  52
  53         spin_lock_init(&port->lock);
  54         port->mapbase = resource.start;
  55
  56         /* Check for shifted address mapping */
  57         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  58                 port->mapbase += prop;
  59
  60         /* Check for registers offset within the devices address range */
  61         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
  62                 port->regshift = prop;
  63
  64         port->irq = irq_of_parse_and_map(np, 0);
  65         port->iotype = UPIO_MEM;
  66         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
  67                 switch (prop) {
  68                 case 1:
  69                         port->iotype = UPIO_MEM;
  70                         break;
  71                 case 4:
  72                         port->iotype = UPIO_MEM32;
  73                         break;
  74                 default:
  75                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
  76                                  prop);
  77                         return -EINVAL;
  78                 }
  79         }
  80
  81         if (of_device_is_compatible(np, "ns8250dw")) {
  82                 ret = serial8250_use_designware_io(port);
  83                 if (ret)
  84                         dev_warn(&ofdev->dev, "unable to register DesignWare 8250 helpers, continuing as a normal 8250\n");
  85         }
  86
  87         port->type = type;
  88         port->uartclk = clk;
  89         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  90                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
  91         port->dev = &ofdev->dev;
  92
  93         return 0;
  94 }
  95
  96 /*
  97  * Try to register a serial port
  98  */
  99 static struct of_device_id of_platform_serial_table[];
 100 static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 101 {
 102         const struct of_device_id *match;
 103         struct of_serial_info *info;
 104         struct uart_port port;
 105         int port_type;
 106         int ret;
 107
 108         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 109         if (!match)
 110                 return -EINVAL;
 111
 112         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 113                 return -EBUSY;
 114
 115         info = kmalloc(sizeof(*info), GFP_KERNEL);
 116         if (info == NULL)
 117                 return -ENOMEM;
 118
 119         port_type = (unsigned long)match->data;
 120         ret = of_platform_serial_setup(ofdev, port_type, &port);
 121         if (ret)
 122                 goto out;
 123
 124         switch (port_type) {
 125 #ifdef CONFIG_SERIAL_8250
 126         case PORT_8250 ... PORT_MAX_8250:
 127                 ret = serial8250_register_port(&port);
 128                 break;
 129 #endif
 130 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 131         case PORT_NWPSERIAL:
 132                 ret = nwpserial_register_port(&port);
 133                 break;
 134 #endif
 135         default:
 136                 /* need to add code for these */
 137         case PORT_UNKNOWN:
 138                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 139                 ret = -ENODEV;
 140                 break;
 141         }
 142         if (ret < 0)
 143                 goto out;
 144
 145         info->type = port_type;
 146         info->line = ret;
 147         dev_set_drvdata(&ofdev->dev, info);
 148         return 0;
 149 out:
 150         kfree(info);
 151         irq_dispose_mapping(port.irq);
 152         return ret;
 153 }
 154
 155 /*
 156  * Release a line
 157  */
 158 static int of_platform_serial_remove(struct platform_device *ofdev)
 159 {
 160         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 161         switch (info->type) {
 162 #ifdef CONFIG_SERIAL_8250
 163         case PORT_8250 ... PORT_MAX_8250:
 164                 serial8250_unregister_port(info->line);
 165                 break;
 166 #endif
 167 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 168         case PORT_NWPSERIAL:
 169                 nwpserial_unregister_port(info->line);
 170                 break;
 171 #endif
 172         default:
 173                 /* need to add code for these */
 174                 break;
 175         }
 176         kfree(info);
 177         return 0;
 178 }
 179
 180 /*
 181  * A few common types, add more as needed.
 182  */
 183 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 184         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 185         { .compatible = "ns8250dw", .data = (void *)PORT_8250, },
 186         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 187         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 188         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 189         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 190         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 191         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 192 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 193         { .compatible = "ibm,qpace-nwp-serial",
 194                 .data = (void *)PORT_NWPSERIAL, },
 195 #endif
 196         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 197         { /* end of list */ },
 198 };
 199
 200 static struct platform_driver of_platform_serial_driver = {
 201         .driver = {
 202                 .name = "of_serial",
 203                 .owner = THIS_MODULE,
 204                 .of_match_table = of_platform_serial_table,
 205         },
 206         .probe = of_platform_serial_probe,
 207         .remove = of_platform_serial_remove,
 208 };
 209
 210 static int __init of_platform_serial_init(void)
 211 {
 212         return platform_driver_register(&of_platform_serial_driver);
 213 }
 214 module_init(of_platform_serial_init);
 215
 216 static void __exit of_platform_serial_exit(void)
 217 {
 218         return platform_driver_unregister(&of_platform_serial_driver);
 219 };
 220 module_exit(of_platform_serial_exit);
 221
 222 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 223 MODULE_LICENSE("GPL");
 224 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");