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 #include <linux/clk.h>
  25
  26 struct of_serial_info {
  27         struct clk *clk;
  28         int type;
  29         int line;
  30 };
  31
  32 #ifdef CONFIG_ARCH_TEGRA
  33 void tegra_serial_handle_break(struct uart_port *p)
  34 {
  35         unsigned int status, tmout = 10000;
  36
  37         do {
  38                 status = p->serial_in(p, UART_LSR);
  39                 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
  40                         status = p->serial_in(p, UART_RX);
  41                 else
  42                         break;
  43                 if (--tmout == 0)
  44                         break;
  45                 udelay(1);
  46         } while (1);
  47 }
  48 /* FIXME remove this export when tegra finishes conversion to open firmware */
  49 EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
  50 #endif
  51
  52 /*
  53  * Fill a struct uart_port for a given device node
  54  */
  55 static int of_platform_serial_setup(struct platform_device *ofdev,
  56                         int type, struct uart_port *port,
  57                         struct of_serial_info *info)
  58 {
  59         struct resource resource;
  60         struct device_node *np = ofdev->dev.of_node;
  61         u32 clk, spd, prop;
  62         int ret;
  63
  64         memset(port, 0, sizeof *port);
  65         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  66
  67                 /* Get clk rate through clk driver if present */
  68                 info->clk = clk_get(&ofdev->dev, NULL);
  69                 if (IS_ERR(info->clk)) {
  70                         dev_warn(&ofdev->dev,
  71                                 "clk or clock-frequency not defined\n");
  72                         return PTR_ERR(info->clk);
  73                 }
  74
  75                 clk_prepare_enable(info->clk);
  76                 clk = clk_get_rate(info->clk);
  77         }
  78         /* If current-speed was set, then try not to change it. */
  79         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  80                 port->custom_divisor = clk / (16 * spd);
  81
  82         ret = of_address_to_resource(np, 0, &resource);
  83         if (ret) {
  84                 dev_warn(&ofdev->dev, "invalid address\n");
  85                 goto out;
  86         }
  87
  88         spin_lock_init(&port->lock);
  89         port->mapbase = resource.start;
  90
  91         /* Check for shifted address mapping */
  92         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  93                 port->mapbase += prop;
  94
  95         /* Check for registers offset within the devices address range */
  96         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
  97                 port->regshift = prop;
  98
  99         port->irq = irq_of_parse_and_map(np, 0);
 100         port->iotype = UPIO_MEM;
 101         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 102                 switch (prop) {
 103                 case 1:
 104                         port->iotype = UPIO_MEM;
 105                         break;
 106                 case 4:
 107                         port->iotype = UPIO_MEM32;
 108                         break;
 109                 default:
 110                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 111                                  prop);
 112                         ret = -EINVAL;
 113                         goto out;
 114                 }
 115         }
 116
 117         port->type = type;
 118         port->uartclk = clk;
 119         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 120                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 121
 122         if (of_find_property(np, "no-loopback-test", NULL))
 123                 port->flags |= UPF_SKIP_TEST;
 124
 125         port->dev = &ofdev->dev;
 126
 127         if (type == PORT_TEGRA)
 128                 port->handle_break = tegra_serial_handle_break;
 129
 130         return 0;
 131 out:
 132         if (info->clk)
 133                 clk_disable_unprepare(info->clk);
 134         return ret;
 135 }
 136
 137 /*
 138  * Try to register a serial port
 139  */
 140 static struct of_device_id of_platform_serial_table[];
 141 static int of_platform_serial_probe(struct platform_device *ofdev)
 142 {
 143         const struct of_device_id *match;
 144         struct of_serial_info *info;
 145         struct uart_port port;
 146         int port_type;
 147         int ret;
 148
 149         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 150         if (!match)
 151                 return -EINVAL;
 152
 153         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 154                 return -EBUSY;
 155
 156         info = kmalloc(sizeof(*info), GFP_KERNEL);
 157         if (info == NULL)
 158                 return -ENOMEM;
 159
 160         port_type = (unsigned long)match->data;
 161         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 162         if (ret)
 163                 goto out;
 164
 165         switch (port_type) {
 166 #ifdef CONFIG_SERIAL_8250
 167         case PORT_8250 ... PORT_MAX_8250:
 168         {
 169                 /* For now the of bindings don't support the extra
 170                    8250 specific bits */
 171                 struct uart_8250_port port8250;
 172                 memset(&port8250, 0, sizeof(port8250));
 173                 port8250.port = port;
 174                 ret = serial8250_register_8250_port(&port8250);
 175                 break;
 176         }
 177 #endif
 178 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 179         case PORT_NWPSERIAL:
 180                 ret = nwpserial_register_port(&port);
 181                 break;
 182 #endif
 183         default:
 184                 /* need to add code for these */
 185         case PORT_UNKNOWN:
 186                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 187                 ret = -ENODEV;
 188                 break;
 189         }
 190         if (ret < 0)
 191                 goto out;
 192
 193         info->type = port_type;
 194         info->line = ret;
 195         dev_set_drvdata(&ofdev->dev, info);
 196         return 0;
 197 out:
 198         kfree(info);
 199         irq_dispose_mapping(port.irq);
 200         return ret;
 201 }
 202
 203 /*
 204  * Release a line
 205  */
 206 static int of_platform_serial_remove(struct platform_device *ofdev)
 207 {
 208         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 209         switch (info->type) {
 210 #ifdef CONFIG_SERIAL_8250
 211         case PORT_8250 ... PORT_MAX_8250:
 212                 serial8250_unregister_port(info->line);
 213                 break;
 214 #endif
 215 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 216         case PORT_NWPSERIAL:
 217                 nwpserial_unregister_port(info->line);
 218                 break;
 219 #endif
 220         default:
 221                 /* need to add code for these */
 222                 break;
 223         }
 224
 225         if (info->clk)
 226                 clk_disable_unprepare(info->clk);
 227         kfree(info);
 228         return 0;
 229 }
 230
 231 /*
 232  * A few common types, add more as needed.
 233  */
 234 static struct of_device_id of_platform_serial_table[] = {
 235         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 236         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 237         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 238         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 239         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 240         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 241         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 242         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 243 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 244         { .compatible = "ibm,qpace-nwp-serial",
 245                 .data = (void *)PORT_NWPSERIAL, },
 246 #endif
 247         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 248         { /* end of list */ },
 249 };
 250
 251 static struct platform_driver of_platform_serial_driver = {
 252         .driver = {
 253                 .name = "of_serial",
 254                 .owner = THIS_MODULE,
 255                 .of_match_table = of_platform_serial_table,
 256         },
 257         .probe = of_platform_serial_probe,
 258         .remove = of_platform_serial_remove,
 259 };
 260
 261 module_platform_driver(of_platform_serial_driver);
 262
 263 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 264 MODULE_LICENSE("GPL");
 265 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");