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/delay.h>
  16 #include <linux/serial_core.h>
  17 #include <linux/serial_8250.h>
  18 #include <linux/serial_reg.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_irq.h>
  21 #include <linux/of_serial.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/nwpserial.h>
  24
  25 struct of_serial_info {
  26         int type;
  27         int line;
  28 };
  29
  30 #ifdef CONFIG_ARCH_TEGRA
  31 void tegra_serial_handle_break(struct uart_port *p)
  32 {
  33         unsigned int status, tmout = 10000;
  34
  35         do {
  36                 status = p->serial_in(p, UART_LSR);
  37                 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
  38                         status = p->serial_in(p, UART_RX);
  39                 else
  40                         break;
  41                 if (--tmout == 0)
  42                         break;
  43                 udelay(1);
  44         } while (1);
  45 }
  46 /* FIXME remove this export when tegra finishes conversion to open firmware */
  47 EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
  48 #endif
  49
  50 /*
  51  * Fill a struct uart_port for a given device node
  52  */
  53 static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
  54                                         int type, struct uart_port *port)
  55 {
  56         struct resource resource;
  57         struct device_node *np = ofdev->dev.of_node;
  58         u32 clk, spd, prop;
  59         int ret;
  60
  61         memset(port, 0, sizeof *port);
  62         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  63                 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
  64                 return -ENODEV;
  65         }
  66         /* If current-speed was set, then try not to change it. */
  67         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  68                 port->custom_divisor = clk / (16 * spd);
  69
  70         ret = of_address_to_resource(np, 0, &resource);
  71         if (ret) {
  72                 dev_warn(&ofdev->dev, "invalid address\n");
  73                 return ret;
  74         }
  75
  76         spin_lock_init(&port->lock);
  77         port->mapbase = resource.start;
  78
  79         /* Check for shifted address mapping */
  80         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  81                 port->mapbase += prop;
  82
  83         /* Check for registers offset within the devices address range */
  84         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
  85                 port->regshift = prop;
  86
  87         port->irq = irq_of_parse_and_map(np, 0);
  88         port->iotype = UPIO_MEM;
  89         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
  90                 switch (prop) {
  91                 case 1:
  92                         port->iotype = UPIO_MEM;
  93                         break;
  94                 case 4:
  95                         port->iotype = UPIO_MEM32;
  96                         break;
  97                 default:
  98                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
  99                                  prop);
 100                         return -EINVAL;
 101                 }
 102         }
 103
 104         port->type = type;
 105         port->uartclk = clk;
 106         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 107                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 108         port->dev = &ofdev->dev;
 109
 110         if (type == PORT_TEGRA)
 111                 port->handle_break = tegra_serial_handle_break;
 112
 113         return 0;
 114 }
 115
 116 /*
 117  * Try to register a serial port
 118  */
 119 static struct of_device_id of_platform_serial_table[];
 120 static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
 121 {
 122         const struct of_device_id *match;
 123         struct of_serial_info *info;
 124         struct uart_port port;
 125         int port_type;
 126         int ret;
 127
 128         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 129         if (!match)
 130                 return -EINVAL;
 131
 132         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 133                 return -EBUSY;
 134
 135         info = kmalloc(sizeof(*info), GFP_KERNEL);
 136         if (info == NULL)
 137                 return -ENOMEM;
 138
 139         port_type = (unsigned long)match->data;
 140         ret = of_platform_serial_setup(ofdev, port_type, &port);
 141         if (ret)
 142                 goto out;
 143
 144         switch (port_type) {
 145 #ifdef CONFIG_SERIAL_8250
 146         case PORT_8250 ... PORT_MAX_8250:
 147                 ret = serial8250_register_port(&port);
 148                 break;
 149 #endif
 150 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 151         case PORT_NWPSERIAL:
 152                 ret = nwpserial_register_port(&port);
 153                 break;
 154 #endif
 155         default:
 156                 /* need to add code for these */
 157         case PORT_UNKNOWN:
 158                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 159                 ret = -ENODEV;
 160                 break;
 161         }
 162         if (ret < 0)
 163                 goto out;
 164
 165         info->type = port_type;
 166         info->line = ret;
 167         dev_set_drvdata(&ofdev->dev, info);
 168         return 0;
 169 out:
 170         kfree(info);
 171         irq_dispose_mapping(port.irq);
 172         return ret;
 173 }
 174
 175 /*
 176  * Release a line
 177  */
 178 static int of_platform_serial_remove(struct platform_device *ofdev)
 179 {
 180         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 181         switch (info->type) {
 182 #ifdef CONFIG_SERIAL_8250
 183         case PORT_8250 ... PORT_MAX_8250:
 184                 serial8250_unregister_port(info->line);
 185                 break;
 186 #endif
 187 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 188         case PORT_NWPSERIAL:
 189                 nwpserial_unregister_port(info->line);
 190                 break;
 191 #endif
 192         default:
 193                 /* need to add code for these */
 194                 break;
 195         }
 196         kfree(info);
 197         return 0;
 198 }
 199
 200 /*
 201  * A few common types, add more as needed.
 202  */
 203 static struct of_device_id __devinitdata of_platform_serial_table[] = {
 204         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 205         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 206         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 207         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 208         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 209         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 210         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 211 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 212         { .compatible = "ibm,qpace-nwp-serial",
 213                 .data = (void *)PORT_NWPSERIAL, },
 214 #endif
 215         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 216         { /* end of list */ },
 217 };
 218
 219 static struct platform_driver of_platform_serial_driver = {
 220         .driver = {
 221                 .name = "of_serial",
 222                 .owner = THIS_MODULE,
 223                 .of_match_table = of_platform_serial_table,
 224         },
 225         .probe = of_platform_serial_probe,
 226         .remove = of_platform_serial_remove,
 227 };
 228
 229 module_platform_driver(of_platform_serial_driver);
 230
 231 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 232 MODULE_LICENSE("GPL");
 233 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");