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