kernel/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         port->mapsize = resource_size(&resource);
  93
  94         /* Check for shifted address mapping */
  95         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  96                 port->mapbase += prop;
  97
  98         /* Check for registers offset within the devices address range */
  99         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 100                 port->regshift = prop;
 101
 102         /* Check for fifo size */
 103         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 104                 port->fifosize = prop;
 105
 106         /* Check for a fixed line number */
 107         ret = of_alias_get_id(np, "serial");
 108         if (ret >= 0)
 109                 port->line = ret;
 110
 111         port->irq = irq_of_parse_and_map(np, 0);
 112         port->iotype = UPIO_MEM;
 113         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 114                 switch (prop) {
 115                 case 1:
 116                         port->iotype = UPIO_MEM;
 117                         break;
 118                 case 4:
 119                         port->iotype = of_device_is_big_endian(np) ?
 120                                        UPIO_MEM32BE : UPIO_MEM32;
 121                         break;
 122                 default:
 123                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 124                                  prop);
 125                         ret = -EINVAL;
 126                         goto out;
 127                 }
 128         }
 129
 130         port->type = type;
 131         port->uartclk = clk;
 132         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 133                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 134
 135         if (of_find_property(np, "no-loopback-test", NULL))
 136                 port->flags |= UPF_SKIP_TEST;
 137
 138         port->dev = &ofdev->dev;
 139
 140         switch (type) {
 141         case PORT_TEGRA:
 142                 port->handle_break = tegra_serial_handle_break;
 143                 break;
 144
 145         case PORT_RT2880:
 146                 port->iotype = UPIO_AU;
 147                 break;
 148         }
 149
 150         return 0;
 151 out:
 152         if (info->clk)
 153                 clk_disable_unprepare(info->clk);
 154         return ret;
 155 }
 156
 157 /*
 158  * Try to register a serial port
 159  */
 160 static const struct of_device_id of_platform_serial_table[];
 161 static int of_platform_serial_probe(struct platform_device *ofdev)
 162 {
 163         const struct of_device_id *match;
 164         struct of_serial_info *info;
 165         struct uart_port port;
 166         int port_type;
 167         int ret;
 168
 169         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 170         if (!match)
 171                 return -EINVAL;
 172
 173         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 174                 return -EBUSY;
 175
 176         info = kzalloc(sizeof(*info), GFP_KERNEL);
 177         if (info == NULL)
 178                 return -ENOMEM;
 179
 180         port_type = (unsigned long)match->data;
 181         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 182         if (ret)
 183                 goto out;
 184
 185         switch (port_type) {
 186 #ifdef CONFIG_SERIAL_8250
 187         case PORT_8250 ... PORT_MAX_8250:
 188         {
 189                 struct uart_8250_port port8250;
 190                 memset(&port8250, 0, sizeof(port8250));
 191                 port.type = port_type;
 192                 port8250.port = port;
 193
 194                 if (port.fifosize)
 195                         port8250.capabilities = UART_CAP_FIFO;
 196
 197                 if (of_property_read_bool(ofdev->dev.of_node,
 198                                           "auto-flow-control"))
 199                         port8250.capabilities |= UART_CAP_AFE;
 200
 201                 ret = serial8250_register_8250_port(&port8250);
 202                 break;
 203         }
 204 #endif
 205 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 206         case PORT_NWPSERIAL:
 207                 ret = nwpserial_register_port(&port);
 208                 break;
 209 #endif
 210         default:
 211                 /* need to add code for these */
 212         case PORT_UNKNOWN:
 213                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 214                 ret = -ENODEV;
 215                 break;
 216         }
 217         if (ret < 0)
 218                 goto out;
 219
 220         info->type = port_type;
 221         info->line = ret;
 222         platform_set_drvdata(ofdev, info);
 223         return 0;
 224 out:
 225         kfree(info);
 226         irq_dispose_mapping(port.irq);
 227         return ret;
 228 }
 229
 230 /*
 231  * Release a line
 232  */
 233 static int of_platform_serial_remove(struct platform_device *ofdev)
 234 {
 235         struct of_serial_info *info = platform_get_drvdata(ofdev);
 236         switch (info->type) {
 237 #ifdef CONFIG_SERIAL_8250
 238         case PORT_8250 ... PORT_MAX_8250:
 239                 serial8250_unregister_port(info->line);
 240                 break;
 241 #endif
 242 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 243         case PORT_NWPSERIAL:
 244                 nwpserial_unregister_port(info->line);
 245                 break;
 246 #endif
 247         default:
 248                 /* need to add code for these */
 249                 break;
 250         }
 251
 252         if (info->clk)
 253                 clk_disable_unprepare(info->clk);
 254         kfree(info);
 255         return 0;
 256 }
 257
 258 #ifdef CONFIG_PM_SLEEP
 259 #ifdef CONFIG_SERIAL_8250
 260 static void of_serial_suspend_8250(struct of_serial_info *info)
 261 {
 262         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 263         struct uart_port *port = &port8250->port;
 264
 265         serial8250_suspend_port(info->line);
 266         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 267                 clk_disable_unprepare(info->clk);
 268 }
 269
 270 static void of_serial_resume_8250(struct of_serial_info *info)
 271 {
 272         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 273         struct uart_port *port = &port8250->port;
 274
 275         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 276                 clk_prepare_enable(info->clk);
 277
 278         serial8250_resume_port(info->line);
 279 }
 280 #else
 281 static inline void of_serial_suspend_8250(struct of_serial_info *info)
 282 {
 283 }
 284
 285 static inline void of_serial_resume_8250(struct of_serial_info *info)
 286 {
 287 }
 288 #endif
 289
 290 static int of_serial_suspend(struct device *dev)
 291 {
 292         struct of_serial_info *info = dev_get_drvdata(dev);
 293
 294         switch (info->type) {
 295         case PORT_8250 ... PORT_MAX_8250:
 296                 of_serial_suspend_8250(info);
 297                 break;
 298         default:
 299                 break;
 300         }
 301
 302         return 0;
 303 }
 304
 305 static int of_serial_resume(struct device *dev)
 306 {
 307         struct of_serial_info *info = dev_get_drvdata(dev);
 308
 309         switch (info->type) {
 310         case PORT_8250 ... PORT_MAX_8250:
 311                 of_serial_resume_8250(info);
 312                 break;
 313         default:
 314                 break;
 315         }
 316
 317         return 0;
 318 }
 319 #endif
 320 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 321
 322 /*
 323  * A few common types, add more as needed.
 324  */
 325 static const struct of_device_id of_platform_serial_table[] = {
 326         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 327         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 328         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 329         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 330         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 331         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 332         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 333         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 334         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 335         { .compatible = "altr,16550-FIFO32",
 336                 .data = (void *)PORT_ALTR_16550_F32, },
 337         { .compatible = "altr,16550-FIFO64",
 338                 .data = (void *)PORT_ALTR_16550_F64, },
 339         { .compatible = "altr,16550-FIFO128",
 340                 .data = (void *)PORT_ALTR_16550_F128, },
 341         { .compatible = "mrvl,mmp-uart",
 342                 .data = (void *)PORT_XSCALE, },
 343         { .compatible = "mrvl,pxa-uart",
 344                 .data = (void *)PORT_XSCALE, },
 345 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 346         { .compatible = "ibm,qpace-nwp-serial",
 347                 .data = (void *)PORT_NWPSERIAL, },
 348 #endif
 349         { /* end of list */ },
 350 };
 351
 352 static struct platform_driver of_platform_serial_driver = {
 353         .driver = {
 354                 .name = "of_serial",
 355                 .of_match_table = of_platform_serial_table,
 356         },
 357         .probe = of_platform_serial_probe,
 358         .remove = of_platform_serial_remove,
 359 };
 360
 361 module_platform_driver(of_platform_serial_driver);
 362
 363 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 364 MODULE_LICENSE("GPL");
 365 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");