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         port->type = type;
  69         port->uartclk = be32_to_cpup(clk);
  70         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  71                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
  72         port->dev = &ofdev->dev;
  73         /* If current-speed was set, then try not to change it. */
  74         if (spd)
  75                 port->custom_divisor = be32_to_cpup(clk) / (16 * (be32_to_cpup(spd)));
  76
  77         return 0;
  78 }
  79
  80 /*
  81  * Try to register a serial port
  82  */
  83 static int __devinit of_platform_serial_probe(struct platform_device *ofdev,
  84                                                 const struct of_device_id *id)
  85 {
  86         struct of_serial_info *info;
  87         struct uart_port port;
  88         int port_type;
  89         int ret;
  90
  91         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
  92                 return -EBUSY;
  93
  94         info = kmalloc(sizeof(*info), GFP_KERNEL);
  95         if (info == NULL)
  96                 return -ENOMEM;
  97
  98         port_type = (unsigned long)id->data;
  99         ret = of_platform_serial_setup(ofdev, port_type, &port);
 100         if (ret)
 101                 goto out;
 102
 103         switch (port_type) {
 104 #ifdef CONFIG_SERIAL_8250
 105         case PORT_8250 ... PORT_MAX_8250:
 106                 ret = serial8250_register_port(&port);
 107                 break;
 108 #endif
 109 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 110         case PORT_NWPSERIAL:
 111                 ret = nwpserial_register_port(&port);
 112                 break;
 113 #endif
 114         default:
 115                 /* need to add code for these */
 116         case PORT_UNKNOWN:
 117                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 118                 ret = -ENODEV;
 119                 break;
 120         }
 121         if (ret < 0)
 122                 goto out;
 123
 124         info->type = port_type;
 125         info->line = ret;
 126         dev_set_drvdata(&ofdev->dev, info);
 127         return 0;
 128 out:
 129         kfree(info);
 130         irq_dispose_mapping(port.irq);
 131         return ret;
 132 }
 133
 134 /*
 135  * Release a line
 136  */
 137 static int of_platform_serial_remove(struct platform_device *ofdev)
 138 {
 139         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 140         switch (info->type) {
 141 #ifdef CONFIG_SERIAL_8250
 142         case PORT_8250 ... PORT_MAX_8250:
 143                 serial8250_unregister_port(info->line);
 144                 break;
 145 #endif
 146 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 147         case PORT_NWPSERIAL:
 148                 nwpserial_unregister_port(info->line);
 149                 break;
 150 #endif
 151         default:
 152                 /* need to add code for these */
 153                 break;
 154         }
 155         kfree(info);
 156         return 0;
 157 }
 158
 159 /*
 160  * A few common types, add more as needed.
 161  */
 162 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 163         { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
 164         { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
 165         { .type = "serial", .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 166         { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
 167         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
 168         { .type = "serial", .compatible = "ns16850",  .data = (void *)PORT_16850, },
 169 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 170         { .type = "serial", .compatible = "ibm,qpace-nwp-serial",
 171                                         .data = (void *)PORT_NWPSERIAL, },
 172 #endif
 173         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
 174         { /* end of list */ },
 175 };
 176
 177 static struct of_platform_driver of_platform_serial_driver = {
 178         .driver = {
 179                 .name = "of_serial",
 180                 .owner = THIS_MODULE,
 181                 .of_match_table = of_platform_serial_table,
 182         },
 183         .probe = of_platform_serial_probe,
 184         .remove = of_platform_serial_remove,
 185 };
 186
 187 static int __init of_platform_serial_init(void)
 188 {
 189         return of_register_platform_driver(&of_platform_serial_driver);
 190 }
 191 module_init(of_platform_serial_init);
 192
 193 static void __exit of_platform_serial_exit(void)
 194 {
 195         return of_unregister_platform_driver(&of_platform_serial_driver);
 196 };
 197 module_exit(of_platform_serial_exit);
 198
 199 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 200 MODULE_LICENSE("GPL");
 201 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");