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/console.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_reg.h>
  18 #include <linux/of_address.h>
  19 #include <linux/of_irq.h>
  20 #include <linux/of_platform.h>
  21 #include <linux/nwpserial.h>
  22 #include <linux/clk.h>
  23
  24 #include "8250/8250.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 #else
  49 static inline void tegra_serial_handle_break(struct uart_port *port)
  50 {
  51 }
  52 #endif
  53
  54 /*
  55  * Fill a struct uart_port for a given device node
  56  */
  57 static int of_platform_serial_setup(struct platform_device *ofdev,
  58                         int type, struct uart_port *port,
  59                         struct of_serial_info *info)
  60 {
  61         struct resource resource;
  62         struct device_node *np = ofdev->dev.of_node;
  63         u32 clk, spd, prop;
  64         int ret;
  65
  66         memset(port, 0, sizeof *port);
  67         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  68
  69                 /* Get clk rate through clk driver if present */
  70                 info->clk = clk_get(&ofdev->dev, NULL);
  71                 if (IS_ERR(info->clk)) {
  72                         dev_warn(&ofdev->dev,
  73                                 "clk or clock-frequency not defined\n");
  74                         return PTR_ERR(info->clk);
  75                 }
  76
  77                 clk_prepare_enable(info->clk);
  78                 clk = clk_get_rate(info->clk);
  79         }
  80         /* If current-speed was set, then try not to change it. */
  81         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  82                 port->custom_divisor = clk / (16 * spd);
  83
  84         ret = of_address_to_resource(np, 0, &resource);
  85         if (ret) {
  86                 dev_warn(&ofdev->dev, "invalid address\n");
  87                 goto out;
  88         }
  89
  90         spin_lock_init(&port->lock);
  91         port->mapbase = resource.start;
  92
  93         /* Check for shifted address mapping */
  94         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  95                 port->mapbase += prop;
  96
  97         /* Check for registers offset within the devices address range */
  98         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
  99                 port->regshift = prop;
 100
 101         /* Check for fifo size */
 102         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 103                 port->fifosize = prop;
 104
 105         /* Check for a fixed line number */
 106         ret = of_alias_get_id(np, "serial");
 107         if (ret >= 0)
 108                 port->line = ret;
 109
 110         port->irq = irq_of_parse_and_map(np, 0);
 111         port->iotype = UPIO_MEM;
 112         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 113                 switch (prop) {
 114                 case 1:
 115                         port->iotype = UPIO_MEM;
 116                         break;
 117                 case 4:
 118                         port->iotype = UPIO_MEM32;
 119                         break;
 120                 default:
 121                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 122                                  prop);
 123                         ret = -EINVAL;
 124                         goto out;
 125                 }
 126         }
 127
 128         port->type = type;
 129         port->uartclk = clk;
 130         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 131                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 132
 133         if (of_find_property(np, "no-loopback-test", NULL))
 134                 port->flags |= UPF_SKIP_TEST;
 135
 136         port->dev = &ofdev->dev;
 137
 138         switch (type) {
 139         case PORT_TEGRA:
 140                 port->handle_break = tegra_serial_handle_break;
 141                 break;
 142
 143         case PORT_RT2880:
 144                 port->iotype = UPIO_AU;
 145                 break;
 146         }
 147
 148         return 0;
 149 out:
 150         if (info->clk)
 151                 clk_disable_unprepare(info->clk);
 152         return ret;
 153 }
 154
 155 /*
 156  * Try to register a serial port
 157  */
 158 static struct of_device_id of_platform_serial_table[];
 159 static int of_platform_serial_probe(struct platform_device *ofdev)
 160 {
 161         const struct of_device_id *match;
 162         struct of_serial_info *info;
 163         struct uart_port port;
 164         int port_type;
 165         int ret;
 166
 167         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 168         if (!match)
 169                 return -EINVAL;
 170
 171         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 172                 return -EBUSY;
 173
 174         info = kzalloc(sizeof(*info), GFP_KERNEL);
 175         if (info == NULL)
 176                 return -ENOMEM;
 177
 178         port_type = (unsigned long)match->data;
 179         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 180         if (ret)
 181                 goto out;
 182
 183         switch (port_type) {
 184 #ifdef CONFIG_SERIAL_8250
 185         case PORT_8250 ... PORT_MAX_8250:
 186         {
 187                 struct uart_8250_port port8250;
 188                 memset(&port8250, 0, sizeof(port8250));
 189                 port.type = port_type;
 190                 port8250.port = port;
 191
 192                 if (port.fifosize)
 193                         port8250.capabilities = UART_CAP_FIFO;
 194
 195                 if (of_property_read_bool(ofdev->dev.of_node,
 196                                           "auto-flow-control"))
 197                         port8250.capabilities |= UART_CAP_AFE;
 198
 199                 ret = serial8250_register_8250_port(&port8250);
 200                 break;
 201         }
 202 #endif
 203 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 204         case PORT_NWPSERIAL:
 205                 ret = nwpserial_register_port(&port);
 206                 break;
 207 #endif
 208         default:
 209                 /* need to add code for these */
 210         case PORT_UNKNOWN:
 211                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 212                 ret = -ENODEV;
 213                 break;
 214         }
 215         if (ret < 0)
 216                 goto out;
 217
 218         info->type = port_type;
 219         info->line = ret;
 220         platform_set_drvdata(ofdev, info);
 221         return 0;
 222 out:
 223         kfree(info);
 224         irq_dispose_mapping(port.irq);
 225         return ret;
 226 }
 227
 228 /*
 229  * Release a line
 230  */
 231 static int of_platform_serial_remove(struct platform_device *ofdev)
 232 {
 233         struct of_serial_info *info = platform_get_drvdata(ofdev);
 234         switch (info->type) {
 235 #ifdef CONFIG_SERIAL_8250
 236         case PORT_8250 ... PORT_MAX_8250:
 237                 serial8250_unregister_port(info->line);
 238                 break;
 239 #endif
 240 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 241         case PORT_NWPSERIAL:
 242                 nwpserial_unregister_port(info->line);
 243                 break;
 244 #endif
 245         default:
 246                 /* need to add code for these */
 247                 break;
 248         }
 249
 250         if (info->clk)
 251                 clk_disable_unprepare(info->clk);
 252         kfree(info);
 253         return 0;
 254 }
 255
 256 #ifdef CONFIG_PM_SLEEP
 257 #ifdef CONFIG_SERIAL_8250
 258 static void of_serial_suspend_8250(struct of_serial_info *info)
 259 {
 260         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 261         struct uart_port *port = &port8250->port;
 262
 263         serial8250_suspend_port(info->line);
 264         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 265                 clk_disable_unprepare(info->clk);
 266 }
 267
 268 static void of_serial_resume_8250(struct of_serial_info *info)
 269 {
 270         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 271         struct uart_port *port = &port8250->port;
 272
 273         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 274                 clk_prepare_enable(info->clk);
 275
 276         serial8250_resume_port(info->line);
 277 }
 278 #else
 279 static inline void of_serial_suspend_8250(struct of_serial_info *info)
 280 {
 281 }
 282
 283 static inline void of_serial_resume_8250(struct of_serial_info *info)
 284 {
 285 }
 286 #endif
 287
 288 static int of_serial_suspend(struct device *dev)
 289 {
 290         struct of_serial_info *info = dev_get_drvdata(dev);
 291
 292         switch (info->type) {
 293         case PORT_8250 ... PORT_MAX_8250:
 294                 of_serial_suspend_8250(info);
 295                 break;
 296         default:
 297                 break;
 298         }
 299
 300         return 0;
 301 }
 302
 303 static int of_serial_resume(struct device *dev)
 304 {
 305         struct of_serial_info *info = dev_get_drvdata(dev);
 306
 307         switch (info->type) {
 308         case PORT_8250 ... PORT_MAX_8250:
 309                 of_serial_resume_8250(info);
 310                 break;
 311         default:
 312                 break;
 313         }
 314
 315         return 0;
 316 }
 317 #endif
 318 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 319
 320 /*
 321  * A few common types, add more as needed.
 322  */
 323 static struct of_device_id of_platform_serial_table[] = {
 324         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 325         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 326         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 327         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 328         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 329         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 330         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 331         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 332         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 333         { .compatible = "altr,16550-FIFO32",
 334                 .data = (void *)PORT_ALTR_16550_F32, },
 335         { .compatible = "altr,16550-FIFO64",
 336                 .data = (void *)PORT_ALTR_16550_F64, },
 337         { .compatible = "altr,16550-FIFO128",
 338                 .data = (void *)PORT_ALTR_16550_F128, },
 339         { .compatible = "mrvl,mmp-uart",
 340                 .data = (void *)PORT_XSCALE, },
 341         { .compatible = "mrvl,pxa-uart",
 342                 .data = (void *)PORT_XSCALE, },
 343 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 344         { .compatible = "ibm,qpace-nwp-serial",
 345                 .data = (void *)PORT_NWPSERIAL, },
 346 #endif
 347         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 348         { /* end of list */ },
 349 };
 350
 351 static struct platform_driver of_platform_serial_driver = {
 352         .driver = {
 353                 .name = "of_serial",
 354                 .of_match_table = of_platform_serial_table,
 355         },
 356         .probe = of_platform_serial_probe,
 357         .remove = of_platform_serial_remove,
 358 };
 359
 360 module_platform_driver(of_platform_serial_driver);
 361
 362 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 363 MODULE_LICENSE("GPL");
 364 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");