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_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         port->irq = irq_of_parse_and_map(np, 0);
 106         port->iotype = UPIO_MEM;
 107         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 108                 switch (prop) {
 109                 case 1:
 110                         port->iotype = UPIO_MEM;
 111                         break;
 112                 case 4:
 113                         port->iotype = UPIO_MEM32;
 114                         break;
 115                 default:
 116                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 117                                  prop);
 118                         ret = -EINVAL;
 119                         goto out;
 120                 }
 121         }
 122
 123         port->type = type;
 124         port->uartclk = clk;
 125         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 126                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 127
 128         if (of_find_property(np, "no-loopback-test", NULL))
 129                 port->flags |= UPF_SKIP_TEST;
 130
 131         port->dev = &ofdev->dev;
 132
 133         if (type == PORT_TEGRA)
 134                 port->handle_break = tegra_serial_handle_break;
 135
 136         return 0;
 137 out:
 138         if (info->clk)
 139                 clk_disable_unprepare(info->clk);
 140         return ret;
 141 }
 142
 143 /*
 144  * Try to register a serial port
 145  */
 146 static struct of_device_id of_platform_serial_table[];
 147 static int of_platform_serial_probe(struct platform_device *ofdev)
 148 {
 149         const struct of_device_id *match;
 150         struct of_serial_info *info;
 151         struct uart_port port;
 152         int port_type;
 153         int ret;
 154
 155         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 156         if (!match)
 157                 return -EINVAL;
 158
 159         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 160                 return -EBUSY;
 161
 162         info = kmalloc(sizeof(*info), GFP_KERNEL);
 163         if (info == NULL)
 164                 return -ENOMEM;
 165
 166         port_type = (unsigned long)match->data;
 167         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 168         if (ret)
 169                 goto out;
 170
 171         switch (port_type) {
 172 #ifdef CONFIG_SERIAL_8250
 173         case PORT_8250 ... PORT_MAX_8250:
 174         {
 175                 struct uart_8250_port port8250;
 176                 memset(&port8250, 0, sizeof(port8250));
 177                 port8250.port = port;
 178
 179                 if (port.fifosize)
 180                         port8250.capabilities = UART_CAP_FIFO;
 181
 182                 if (of_property_read_bool(ofdev->dev.of_node,
 183                                           "auto-flow-control"))
 184                         port8250.capabilities |= UART_CAP_AFE;
 185
 186                 ret = serial8250_register_8250_port(&port8250);
 187                 break;
 188         }
 189 #endif
 190 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 191         case PORT_NWPSERIAL:
 192                 ret = nwpserial_register_port(&port);
 193                 break;
 194 #endif
 195         default:
 196                 /* need to add code for these */
 197         case PORT_UNKNOWN:
 198                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 199                 ret = -ENODEV;
 200                 break;
 201         }
 202         if (ret < 0)
 203                 goto out;
 204
 205         info->type = port_type;
 206         info->line = ret;
 207         platform_set_drvdata(ofdev, info);
 208         return 0;
 209 out:
 210         kfree(info);
 211         irq_dispose_mapping(port.irq);
 212         return ret;
 213 }
 214
 215 /*
 216  * Release a line
 217  */
 218 static int of_platform_serial_remove(struct platform_device *ofdev)
 219 {
 220         struct of_serial_info *info = platform_get_drvdata(ofdev);
 221         switch (info->type) {
 222 #ifdef CONFIG_SERIAL_8250
 223         case PORT_8250 ... PORT_MAX_8250:
 224                 serial8250_unregister_port(info->line);
 225                 break;
 226 #endif
 227 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 228         case PORT_NWPSERIAL:
 229                 nwpserial_unregister_port(info->line);
 230                 break;
 231 #endif
 232         default:
 233                 /* need to add code for these */
 234                 break;
 235         }
 236
 237         if (info->clk)
 238                 clk_disable_unprepare(info->clk);
 239         kfree(info);
 240         return 0;
 241 }
 242
 243 /*
 244  * A few common types, add more as needed.
 245  */
 246 static struct of_device_id of_platform_serial_table[] = {
 247         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 248         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 249         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 250         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 251         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 252         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 253         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 254         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 255         { .compatible = "altr,16550-FIFO32",
 256                 .data = (void *)PORT_ALTR_16550_F32, },
 257         { .compatible = "altr,16550-FIFO64",
 258                 .data = (void *)PORT_ALTR_16550_F64, },
 259         { .compatible = "altr,16550-FIFO128",
 260                 .data = (void *)PORT_ALTR_16550_F128, },
 261 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 262         { .compatible = "ibm,qpace-nwp-serial",
 263                 .data = (void *)PORT_NWPSERIAL, },
 264 #endif
 265         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 266         { /* end of list */ },
 267 };
 268
 269 static struct platform_driver of_platform_serial_driver = {
 270         .driver = {
 271                 .name = "of_serial",
 272                 .owner = THIS_MODULE,
 273                 .of_match_table = of_platform_serial_table,
 274         },
 275         .probe = of_platform_serial_probe,
 276         .remove = of_platform_serial_remove,
 277 };
 278
 279 module_platform_driver(of_platform_serial_driver);
 280
 281 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 282 MODULE_LICENSE("GPL");
 283 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");