drivers/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/serial_core.h>
  15 #include <linux/serial_8250.h>
  16 #include <linux/of_platform.h>
  17
  18 #include <asm/prom.h>
  19
  20 struct of_serial_info {
  21         int type;
  22         int line;
  23 };
  24
  25 /*
  26  * Fill a struct uart_port for a given device node
  27  */
  28 static int __devinit of_platform_serial_setup(struct of_device *ofdev,
  29                                         int type, struct uart_port *port)
  30 {
  31         struct resource resource;
  32         struct device_node *np = ofdev->node;
  33         const unsigned int *clk, *spd;
  34         const u32 *prop;
  35         int ret, prop_size;
  36
  37         memset(port, 0, sizeof *port);
  38         spd = of_get_property(np, "current-speed", NULL);
  39         clk = of_get_property(np, "clock-frequency", NULL);
  40         if (!clk) {
  41                 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  42                 return -ENODEV;
  43         }
  44
  45         ret = of_address_to_resource(np, 0, &resource);
  46         if (ret) {
  47                 dev_warn(&ofdev->dev, "invalid address\n");
  48                 return ret;
  49         }
  50
  51         spin_lock_init(&port->lock);
  52         port->mapbase = resource.start;
  53
  54         /* Check for shifted address mapping */
  55         prop = of_get_property(np, "reg-offset", &prop_size);
  56         if (prop && (prop_size == sizeof(u32)))
  57                 port->mapbase += *prop;
  58
  59         /* Check for registers offset within the devices address range */
  60         prop = of_get_property(np, "reg-shift", &prop_size);
  61         if (prop && (prop_size == sizeof(u32)))
  62                 port->regshift = *prop;
  63
  64         port->irq = irq_of_parse_and_map(np, 0);
  65         port->iotype = UPIO_MEM;
  66         port->type = type;
  67         port->uartclk = *clk;
  68         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
  69                 | UPF_FIXED_PORT;
  70         port->dev = &ofdev->dev;
  71         /* If current-speed was set, then try not to change it. */
  72         if (spd)
  73                 port->custom_divisor = *clk / (16 * (*spd));
  74
  75         return 0;
  76 }
  77
  78 /*
  79  * Try to register a serial port
  80  */
  81 static int __devinit of_platform_serial_probe(struct of_device *ofdev,
  82                                                 const struct of_device_id *id)
  83 {
  84         struct of_serial_info *info;
  85         struct uart_port port;
  86         int port_type;
  87         int ret;
  88
  89         if (of_find_property(ofdev->node, "used-by-rtas", NULL))
  90                 return -EBUSY;
  91
  92         info = kmalloc(sizeof(*info), GFP_KERNEL);
  93         if (info == NULL)
  94                 return -ENOMEM;
  95
  96         port_type = (unsigned long)id->data;
  97         ret = of_platform_serial_setup(ofdev, port_type, &port);
  98         if (ret)
  99                 goto out;
 100
 101         switch (port_type) {
 102         case PORT_8250 ... PORT_MAX_8250:
 103                 ret = serial8250_register_port(&port);
 104                 break;
 105         default:
 106                 /* need to add code for these */
 107         case PORT_UNKNOWN:
 108                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 109                 ret = -ENODEV;
 110                 break;
 111         }
 112         if (ret < 0)
 113                 goto out;
 114
 115         info->type = port_type;
 116         info->line = ret;
 117         ofdev->dev.driver_data = info;
 118         return 0;
 119 out:
 120         kfree(info);
 121         irq_dispose_mapping(port.irq);
 122         return ret;
 123 }
 124
 125 /*
 126  * Release a line
 127  */
 128 static int of_platform_serial_remove(struct of_device *ofdev)
 129 {
 130         struct of_serial_info *info = ofdev->dev.driver_data;
 131         switch (info->type) {
 132         case PORT_8250 ... PORT_MAX_8250:
 133                 serial8250_unregister_port(info->line);
 134                 break;
 135         default:
 136                 /* need to add code for these */
 137                 break;
 138         }
 139         kfree(info);
 140         return 0;
 141 }
 142
 143 /*
 144  * A few common types, add more as needed.
 145  */
 146 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 147         { .type = "serial", .compatible = "ns8250",   .data = (void *)PORT_8250, },
 148         { .type = "serial", .compatible = "ns16450",  .data = (void *)PORT_16450, },
 149         { .type = "serial", .compatible = "ns16550",  .data = (void *)PORT_16550, },
 150         { .type = "serial", .compatible = "ns16750",  .data = (void *)PORT_16750, },
 151         { .type = "serial",                           .data = (void *)PORT_UNKNOWN, },
 152         { /* end of list */ },
 153 };
 154
 155 static struct of_platform_driver of_platform_serial_driver = {
 156         .owner = THIS_MODULE,
 157         .name = "of_serial",
 158         .probe = of_platform_serial_probe,
 159         .remove = of_platform_serial_remove,
 160         .match_table = of_platform_serial_table,
 161 };
 162
 163 static int __init of_platform_serial_init(void)
 164 {
 165         return of_register_platform_driver(&of_platform_serial_driver);
 166 }
 167 module_init(of_platform_serial_init);
 168
 169 static void __exit of_platform_serial_exit(void)
 170 {
 171         return of_unregister_platform_driver(&of_platform_serial_driver);
 172 };
 173 module_exit(of_platform_serial_exit);
 174
 175 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 176 MODULE_LICENSE("GPL");
 177 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");