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         const __be32 *clk, *spd;
  36         const __be32 *prop;
  37         int ret, prop_size;
  38
  39         memset(port, 0, sizeof *port);
  40         spd = of_get_property(np, "current-speed", NULL);
  41         clk = of_get_property(np, "clock-frequency", NULL);
  42         if (!clk) {
  43                 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  44                 return -ENODEV;
  45         }
  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         prop = of_get_property(np, "reg-offset", &prop_size);
  58         if (prop && (prop_size == sizeof(u32)))
  59                 port->mapbase += be32_to_cpup(prop);
  60
  61         /* Check for registers offset within the devices address range */
  62         prop = of_get_property(np, "reg-shift", &prop_size);
  63         if (prop && (prop_size == sizeof(u32)))
  64                 port->regshift = be32_to_cpup(prop);
  65
  66         port->irq = irq_of_parse_and_map(np, 0);
  67         port->iotype = UPIO_MEM;
  68         prop = of_get_property(np, "reg-io-width", &prop_size);
  69         if (prop && (prop_size == sizeof(u32))) {
  70                 switch (be32_to_cpup(prop)) {
  71                 case 1:
  72                         port->iotype = UPIO_MEM;
  73                         break;
  74                 case 4:
  75                         port->iotype = UPIO_MEM32;
  76                         break;
  77                 default:
  78                         dev_warn(&ofdev->dev,
  79                                  "unsupported io width (%d bytes)\n",
  80                                  be32_to_cpup(prop));
  81                         return -EINVAL;
  82                 }
  83         }
  84
  85         port->type = type;
  86         port->uartclk = be32_to_cpup(clk);
  87         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  88                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
  89         port->dev = &ofdev->dev;
  90         /* If current-speed was set, then try not to change it. */
  91         if (spd)
  92                 port->custom_divisor = be32_to_cpup(clk) / (16 * (be32_to_cpup(spd)));
  93
  94         return 0;
  95 }
  96
  97 /*
  98  * Try to register a serial port
  99  */
 100 static struct of_device_id of_platform_serial_table[];
 101 static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 102 {
 103         const struct of_device_id *match;
 104         struct of_serial_info *info;
 105         struct uart_port port;
 106         int port_type;
 107         int ret;
 108
 109         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 110         if (!match)
 111                 return -EINVAL;
 112
 113         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 114                 return -EBUSY;
 115
 116         info = kmalloc(sizeof(*info), GFP_KERNEL);
 117         if (info == NULL)
 118                 return -ENOMEM;
 119
 120         port_type = (unsigned long)match->data;
 121         ret = of_platform_serial_setup(ofdev, port_type, &port);
 122         if (ret)
 123                 goto out;
 124
 125         switch (port_type) {
 126 #ifdef CONFIG_SERIAL_8250
 127         case PORT_8250 ... PORT_MAX_8250:
 128                 ret = serial8250_register_port(&port);
 129                 break;
 130 #endif
 131 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 132         case PORT_NWPSERIAL:
 133                 ret = nwpserial_register_port(&port);
 134                 break;
 135 #endif
 136         default:
 137                 /* need to add code for these */
 138         case PORT_UNKNOWN:
 139                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 140                 ret = -ENODEV;
 141                 break;
 142         }
 143         if (ret < 0)
 144                 goto out;
 145
 146         info->type = port_type;
 147         info->line = ret;
 148         dev_set_drvdata(&ofdev->dev, info);
 149         return 0;
 150 out:
 151         kfree(info);
 152         irq_dispose_mapping(port.irq);
 153         return ret;
 154 }
 155
 156 /*
 157  * Release a line
 158  */
 159 static int of_platform_serial_remove(struct platform_device *ofdev)
 160 {
 161         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 162         switch (info->type) {
 163 #ifdef CONFIG_SERIAL_8250
 164         case PORT_8250 ... PORT_MAX_8250:
 165                 serial8250_unregister_port(info->line);
 166                 break;
 167 #endif
 168 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 169         case PORT_NWPSERIAL:
 170                 nwpserial_unregister_port(info->line);
 171                 break;
 172 #endif
 173         default:
 174                 /* need to add code for these */
 175                 break;
 176         }
 177         kfree(info);
 178         return 0;
 179 }
 180
 181 /*
 182  * A few common types, add more as needed.
 183  */
 184 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 185         { .compatible = "ns8250",   .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 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 192         { .compatible = "ibm,qpace-nwp-serial",
 193                 .data = (void *)PORT_NWPSERIAL, },
 194 #endif
 195         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 196         { /* end of list */ },
 197 };
 198
 199 static struct platform_driver of_platform_serial_driver = {
 200         .driver = {
 201                 .name = "of_serial",
 202                 .owner = THIS_MODULE,
 203                 .of_match_table = of_platform_serial_table,
 204         },
 205         .probe = of_platform_serial_probe,
 206         .remove = of_platform_serial_remove,
 207 };
 208
 209 static int __init of_platform_serial_init(void)
 210 {
 211         return platform_driver_register(&of_platform_serial_driver);
 212 }
 213 module_init(of_platform_serial_init);
 214
 215 static void __exit of_platform_serial_exit(void)
 216 {
 217         return platform_driver_unregister(&of_platform_serial_driver);
 218 };
 219 module_exit(of_platform_serial_exit);
 220
 221 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 222 MODULE_LICENSE("GPL");
 223 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");