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 #ifdef CONFIG_SERIAL_8250_MODULE
  25 #define CONFIG_SERIAL_8250 CONFIG_SERIAL_8250_MODULE
  26 #endif
  27
  28 #include "8250/8250.h"
  29
  30 struct of_serial_info {
  31         struct clk *clk;
  32         int type;
  33         int line;
  34 };
  35
  36 #ifdef CONFIG_ARCH_TEGRA
  37 void tegra_serial_handle_break(struct uart_port *p)
  38 {
  39         unsigned int status, tmout = 10000;
  40
  41         do {
  42                 status = p->serial_in(p, UART_LSR);
  43                 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
  44                         status = p->serial_in(p, UART_RX);
  45                 else
  46                         break;
  47                 if (--tmout == 0)
  48                         break;
  49                 udelay(1);
  50         } while (1);
  51 }
  52 #else
  53 static inline void tegra_serial_handle_break(struct uart_port *port)
  54 {
  55 }
  56 #endif
  57
  58 /*
  59  * Fill a struct uart_port for a given device node
  60  */
  61 static int of_platform_serial_setup(struct platform_device *ofdev,
  62                         int type, struct uart_port *port,
  63                         struct of_serial_info *info)
  64 {
  65         struct resource resource;
  66         struct device_node *np = ofdev->dev.of_node;
  67         u32 clk, spd, prop;
  68         int ret;
  69
  70         memset(port, 0, sizeof *port);
  71         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  72
  73                 /* Get clk rate through clk driver if present */
  74                 info->clk = devm_clk_get(&ofdev->dev, NULL);
  75                 if (IS_ERR(info->clk)) {
  76                         dev_warn(&ofdev->dev,
  77                                 "clk or clock-frequency not defined\n");
  78                         return PTR_ERR(info->clk);
  79                 }
  80
  81                 ret = clk_prepare_enable(info->clk);
  82                 if (ret < 0)
  83                         return ret;
  84
  85                 clk = clk_get_rate(info->clk);
  86         }
  87         /* If current-speed was set, then try not to change it. */
  88         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  89                 port->custom_divisor = clk / (16 * spd);
  90
  91         ret = of_address_to_resource(np, 0, &resource);
  92         if (ret) {
  93                 dev_warn(&ofdev->dev, "invalid address\n");
  94                 goto out;
  95         }
  96
  97         spin_lock_init(&port->lock);
  98         port->mapbase = resource.start;
  99         port->mapsize = resource_size(&resource);
 100
 101         /* Check for shifted address mapping */
 102         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
 103                 port->mapbase += prop;
 104
 105         /* Check for registers offset within the devices address range */
 106         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 107                 port->regshift = prop;
 108
 109         /* Check for fifo size */
 110         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 111                 port->fifosize = prop;
 112
 113         /* Check for a fixed line number */
 114         ret = of_alias_get_id(np, "serial");
 115         if (ret >= 0)
 116                 port->line = ret;
 117
 118         port->irq = irq_of_parse_and_map(np, 0);
 119         port->iotype = UPIO_MEM;
 120         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 121                 switch (prop) {
 122                 case 1:
 123                         port->iotype = UPIO_MEM;
 124                         break;
 125                 case 2:
 126                         port->iotype = UPIO_MEM16;
 127                         break;
 128                 case 4:
 129                         port->iotype = of_device_is_big_endian(np) ?
 130                                        UPIO_MEM32BE : UPIO_MEM32;
 131                         break;
 132                 default:
 133                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 134                                  prop);
 135                         ret = -EINVAL;
 136                         goto out;
 137                 }
 138         }
 139
 140         port->type = type;
 141         port->uartclk = clk;
 142         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 143                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 144
 145         if (of_find_property(np, "no-loopback-test", NULL))
 146                 port->flags |= UPF_SKIP_TEST;
 147
 148         port->dev = &ofdev->dev;
 149
 150         switch (type) {
 151         case PORT_TEGRA:
 152                 port->handle_break = tegra_serial_handle_break;
 153                 break;
 154
 155         case PORT_RT2880:
 156                 port->iotype = UPIO_AU;
 157                 break;
 158         }
 159
 160         if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
 161             (of_device_is_compatible(np, "fsl,ns16550") ||
 162              of_device_is_compatible(np, "fsl,16550-FIFO64")))
 163                 port->handle_irq = fsl8250_handle_irq;
 164
 165         return 0;
 166 out:
 167         if (info->clk)
 168                 clk_disable_unprepare(info->clk);
 169         return ret;
 170 }
 171
 172 /*
 173  * Try to register a serial port
 174  */
 175 static const struct of_device_id of_platform_serial_table[];
 176 static int of_platform_serial_probe(struct platform_device *ofdev)
 177 {
 178         const struct of_device_id *match;
 179         struct of_serial_info *info;
 180         struct uart_port port;
 181         int port_type;
 182         int ret;
 183
 184         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 185         if (!match)
 186                 return -EINVAL;
 187
 188         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 189                 return -EBUSY;
 190
 191         info = kzalloc(sizeof(*info), GFP_KERNEL);
 192         if (info == NULL)
 193                 return -ENOMEM;
 194
 195         port_type = (unsigned long)match->data;
 196         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 197         if (ret)
 198                 goto out;
 199
 200         switch (port_type) {
 201 #ifdef CONFIG_SERIAL_8250
 202         case PORT_8250 ... PORT_MAX_8250:
 203         {
 204                 struct uart_8250_port port8250;
 205                 memset(&port8250, 0, sizeof(port8250));
 206                 port8250.port = port;
 207
 208                 if (port.fifosize)
 209                         port8250.capabilities = UART_CAP_FIFO;
 210
 211                 if (of_property_read_bool(ofdev->dev.of_node,
 212                                           "auto-flow-control"))
 213                         port8250.capabilities |= UART_CAP_AFE;
 214
 215                 ret = serial8250_register_8250_port(&port8250);
 216                 break;
 217         }
 218 #endif
 219         default:
 220                 /* need to add code for these */
 221         case PORT_UNKNOWN:
 222                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 223                 ret = -ENODEV;
 224                 break;
 225         }
 226         if (ret < 0)
 227                 goto out;
 228
 229         info->type = port_type;
 230         info->line = ret;
 231         platform_set_drvdata(ofdev, info);
 232         return 0;
 233 out:
 234         kfree(info);
 235         irq_dispose_mapping(port.irq);
 236         return ret;
 237 }
 238
 239 /*
 240  * Release a line
 241  */
 242 static int of_platform_serial_remove(struct platform_device *ofdev)
 243 {
 244         struct of_serial_info *info = platform_get_drvdata(ofdev);
 245         switch (info->type) {
 246 #ifdef CONFIG_SERIAL_8250
 247         case PORT_8250 ... PORT_MAX_8250:
 248                 serial8250_unregister_port(info->line);
 249                 break;
 250 #endif
 251         default:
 252                 /* need to add code for these */
 253                 break;
 254         }
 255
 256         if (info->clk)
 257                 clk_disable_unprepare(info->clk);
 258         kfree(info);
 259         return 0;
 260 }
 261
 262 #ifdef CONFIG_PM_SLEEP
 263 #ifdef CONFIG_SERIAL_8250
 264 static void of_serial_suspend_8250(struct of_serial_info *info)
 265 {
 266         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 267         struct uart_port *port = &port8250->port;
 268
 269         serial8250_suspend_port(info->line);
 270         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 271                 clk_disable_unprepare(info->clk);
 272 }
 273
 274 static void of_serial_resume_8250(struct of_serial_info *info)
 275 {
 276         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 277         struct uart_port *port = &port8250->port;
 278
 279         if (info->clk && (!uart_console(port) || console_suspend_enabled))
 280                 clk_prepare_enable(info->clk);
 281
 282         serial8250_resume_port(info->line);
 283 }
 284 #else
 285 static inline void of_serial_suspend_8250(struct of_serial_info *info)
 286 {
 287 }
 288
 289 static inline void of_serial_resume_8250(struct of_serial_info *info)
 290 {
 291 }
 292 #endif
 293
 294 static int of_serial_suspend(struct device *dev)
 295 {
 296         struct of_serial_info *info = dev_get_drvdata(dev);
 297
 298         switch (info->type) {
 299         case PORT_8250 ... PORT_MAX_8250:
 300                 of_serial_suspend_8250(info);
 301                 break;
 302         default:
 303                 break;
 304         }
 305
 306         return 0;
 307 }
 308
 309 static int of_serial_resume(struct device *dev)
 310 {
 311         struct of_serial_info *info = dev_get_drvdata(dev);
 312
 313         switch (info->type) {
 314         case PORT_8250 ... PORT_MAX_8250:
 315                 of_serial_resume_8250(info);
 316                 break;
 317         default:
 318                 break;
 319         }
 320
 321         return 0;
 322 }
 323 #endif
 324 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 325
 326 /*
 327  * A few common types, add more as needed.
 328  */
 329 static const struct of_device_id of_platform_serial_table[] = {
 330         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 331         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 332         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 333         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 334         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 335         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 336         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 337         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 338         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 339         { .compatible = "altr,16550-FIFO32",
 340                 .data = (void *)PORT_ALTR_16550_F32, },
 341         { .compatible = "altr,16550-FIFO64",
 342                 .data = (void *)PORT_ALTR_16550_F64, },
 343         { .compatible = "altr,16550-FIFO128",
 344                 .data = (void *)PORT_ALTR_16550_F128, },
 345         { .compatible = "mrvl,mmp-uart",
 346                 .data = (void *)PORT_XSCALE, },
 347         { .compatible = "mrvl,pxa-uart",
 348                 .data = (void *)PORT_XSCALE, },
 349         { /* end of list */ },
 350 };
 351 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
 352
 353 static struct platform_driver of_platform_serial_driver = {
 354         .driver = {
 355                 .name = "of_serial",
 356                 .of_match_table = of_platform_serial_table,
 357         },
 358         .probe = of_platform_serial_probe,
 359         .remove = of_platform_serial_remove,
 360 };
 361
 362 module_platform_driver(of_platform_serial_driver);
 363
 364 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 365 MODULE_LICENSE("GPL");
 366 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");