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