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         port->type = type;
  82         port->uartclk = clk;
  83         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  84                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
  85         port->dev = &ofdev->dev;
  86
  87         return 0;
  88 }
  89
  90 /*
  91  * Try to register a serial port
  92  */
  93 static struct of_device_id of_platform_serial_table[];
  94 static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
  95 {
  96         const struct of_device_id *match;
  97         struct of_serial_info *info;
  98         struct uart_port port;
  99         int port_type;
 100         int ret;
 101
 102         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 103         if (!match)
 104                 return -EINVAL;
 105
 106         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 107                 return -EBUSY;
 108
 109         info = kmalloc(sizeof(*info), GFP_KERNEL);
 110         if (info == NULL)
 111                 return -ENOMEM;
 112
 113         port_type = (unsigned long)match->data;
 114         ret = of_platform_serial_setup(ofdev, port_type, &port);
 115         if (ret)
 116                 goto out;
 117
 118         switch (port_type) {
 119 #ifdef CONFIG_SERIAL_8250
 120         case PORT_8250 ... PORT_MAX_8250:
 121                 ret = serial8250_register_port(&port);
 122                 break;
 123 #endif
 124 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 125         case PORT_NWPSERIAL:
 126                 ret = nwpserial_register_port(&port);
 127                 break;
 128 #endif
 129         default:
 130                 /* need to add code for these */
 131         case PORT_UNKNOWN:
 132                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 133                 ret = -ENODEV;
 134                 break;
 135         }
 136         if (ret < 0)
 137                 goto out;
 138
 139         info->type = port_type;
 140         info->line = ret;
 141         dev_set_drvdata(&ofdev->dev, info);
 142         return 0;
 143 out:
 144         kfree(info);
 145         irq_dispose_mapping(port.irq);
 146         return ret;
 147 }
 148
 149 /*
 150  * Release a line
 151  */
 152 static int of_platform_serial_remove(struct platform_device *ofdev)
 153 {
 154         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 155         switch (info->type) {
 156 #ifdef CONFIG_SERIAL_8250
 157         case PORT_8250 ... PORT_MAX_8250:
 158                 serial8250_unregister_port(info->line);
 159                 break;
 160 #endif
 161 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 162         case PORT_NWPSERIAL:
 163                 nwpserial_unregister_port(info->line);
 164                 break;
 165 #endif
 166         default:
 167                 /* need to add code for these */
 168                 break;
 169         }
 170         kfree(info);
 171         return 0;
 172 }
 173
 174 /*
 175  * A few common types, add more as needed.
 176  */
 177 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 178         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 179         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 180         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 181         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 182         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 183         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 184         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 185 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 186         { .compatible = "ibm,qpace-nwp-serial",
 187                 .data = (void *)PORT_NWPSERIAL, },
 188 #endif
 189         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 190         { /* end of list */ },
 191 };
 192
 193 static struct platform_driver of_platform_serial_driver = {
 194         .driver = {
 195                 .name = "of_serial",
 196                 .owner = THIS_MODULE,
 197                 .of_match_table = of_platform_serial_table,
 198         },
 199         .probe = of_platform_serial_probe,
 200         .remove = of_platform_serial_remove,
 201 };
 202
 203 static int __init of_platform_serial_init(void)
 204 {
 205         return platform_driver_register(&of_platform_serial_driver);
 206 }
 207 module_init(of_platform_serial_init);
 208
 209 static void __exit of_platform_serial_exit(void)
 210 {
 211         return platform_driver_unregister(&of_platform_serial_driver);
 212 };
 213 module_exit(of_platform_serial_exit);
 214
 215 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 216 MODULE_LICENSE("GPL");
 217 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");