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/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/delay.h>
  15 #include <linux/serial_core.h>
  16 #include <linux/serial_reg.h>
  17 #include <linux/of_address.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/nwpserial.h>
  21 #include <linux/clk.h>
  22
  23 #include "8250/8250.h"
  24
  25 struct of_serial_info {
  26         struct clk *clk;
  27         int type;
  28         int line;
  29 };
  30
  31 #ifdef CONFIG_ARCH_TEGRA
  32 void tegra_serial_handle_break(struct uart_port *p)
  33 {
  34         unsigned int status, tmout = 10000;
  35
  36         do {
  37                 status = p->serial_in(p, UART_LSR);
  38                 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
  39                         status = p->serial_in(p, UART_RX);
  40                 else
  41                         break;
  42                 if (--tmout == 0)
  43                         break;
  44                 udelay(1);
  45         } while (1);
  46 }
  47 #else
  48 static inline void tegra_serial_handle_break(struct uart_port *port)
  49 {
  50 }
  51 #endif
  52
  53 /*
  54  * Fill a struct uart_port for a given device node
  55  */
  56 static int of_platform_serial_setup(struct platform_device *ofdev,
  57                         int type, struct uart_port *port,
  58                         struct of_serial_info *info)
  59 {
  60         struct resource resource;
  61         struct device_node *np = ofdev->dev.of_node;
  62         u32 clk, spd, prop;
  63         int ret;
  64
  65         memset(port, 0, sizeof *port);
  66         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  67
  68                 /* Get clk rate through clk driver if present */
  69                 info->clk = clk_get(&ofdev->dev, NULL);
  70                 if (IS_ERR(info->clk)) {
  71                         dev_warn(&ofdev->dev,
  72                                 "clk or clock-frequency not defined\n");
  73                         return PTR_ERR(info->clk);
  74                 }
  75
  76                 clk_prepare_enable(info->clk);
  77                 clk = clk_get_rate(info->clk);
  78         }
  79         /* If current-speed was set, then try not to change it. */
  80         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  81                 port->custom_divisor = clk / (16 * spd);
  82
  83         ret = of_address_to_resource(np, 0, &resource);
  84         if (ret) {
  85                 dev_warn(&ofdev->dev, "invalid address\n");
  86                 goto out;
  87         }
  88
  89         spin_lock_init(&port->lock);
  90         port->mapbase = resource.start;
  91
  92         /* Check for shifted address mapping */
  93         if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  94                 port->mapbase += prop;
  95
  96         /* Check for registers offset within the devices address range */
  97         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
  98                 port->regshift = prop;
  99
 100         /* Check for fifo size */
 101         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 102                 port->fifosize = prop;
 103
 104         port->irq = irq_of_parse_and_map(np, 0);
 105         port->iotype = UPIO_MEM;
 106         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 107                 switch (prop) {
 108                 case 1:
 109                         port->iotype = UPIO_MEM;
 110                         break;
 111                 case 4:
 112                         port->iotype = UPIO_MEM32;
 113                         break;
 114                 default:
 115                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 116                                  prop);
 117                         ret = -EINVAL;
 118                         goto out;
 119                 }
 120         }
 121
 122         port->type = type;
 123         port->uartclk = clk;
 124         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 125                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 126
 127         if (of_find_property(np, "no-loopback-test", NULL))
 128                 port->flags |= UPF_SKIP_TEST;
 129
 130         port->dev = &ofdev->dev;
 131
 132         if (type == PORT_TEGRA)
 133                 port->handle_break = tegra_serial_handle_break;
 134
 135         return 0;
 136 out:
 137         if (info->clk)
 138                 clk_disable_unprepare(info->clk);
 139         return ret;
 140 }
 141
 142 /*
 143  * Try to register a serial port
 144  */
 145 static struct of_device_id of_platform_serial_table[];
 146 static int of_platform_serial_probe(struct platform_device *ofdev)
 147 {
 148         const struct of_device_id *match;
 149         struct of_serial_info *info;
 150         struct uart_port port;
 151         int port_type;
 152         int ret;
 153
 154         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 155         if (!match)
 156                 return -EINVAL;
 157
 158         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 159                 return -EBUSY;
 160
 161         info = kmalloc(sizeof(*info), GFP_KERNEL);
 162         if (info == NULL)
 163                 return -ENOMEM;
 164
 165         port_type = (unsigned long)match->data;
 166         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 167         if (ret)
 168                 goto out;
 169
 170         switch (port_type) {
 171 #ifdef CONFIG_SERIAL_8250
 172         case PORT_8250 ... PORT_MAX_8250:
 173         {
 174                 struct uart_8250_port port8250;
 175                 memset(&port8250, 0, sizeof(port8250));
 176                 port8250.port = port;
 177
 178                 if (port.fifosize)
 179                         port8250.capabilities = UART_CAP_FIFO;
 180
 181                 if (of_property_read_bool(ofdev->dev.of_node,
 182                                           "auto-flow-control"))
 183                         port8250.capabilities |= UART_CAP_AFE;
 184
 185                 ret = serial8250_register_8250_port(&port8250);
 186                 break;
 187         }
 188 #endif
 189 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 190         case PORT_NWPSERIAL:
 191                 ret = nwpserial_register_port(&port);
 192                 break;
 193 #endif
 194         default:
 195                 /* need to add code for these */
 196         case PORT_UNKNOWN:
 197                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 198                 ret = -ENODEV;
 199                 break;
 200         }
 201         if (ret < 0)
 202                 goto out;
 203
 204         info->type = port_type;
 205         info->line = ret;
 206         platform_set_drvdata(ofdev, info);
 207         return 0;
 208 out:
 209         kfree(info);
 210         irq_dispose_mapping(port.irq);
 211         return ret;
 212 }
 213
 214 /*
 215  * Release a line
 216  */
 217 static int of_platform_serial_remove(struct platform_device *ofdev)
 218 {
 219         struct of_serial_info *info = platform_get_drvdata(ofdev);
 220         switch (info->type) {
 221 #ifdef CONFIG_SERIAL_8250
 222         case PORT_8250 ... PORT_MAX_8250:
 223                 serial8250_unregister_port(info->line);
 224                 break;
 225 #endif
 226 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 227         case PORT_NWPSERIAL:
 228                 nwpserial_unregister_port(info->line);
 229                 break;
 230 #endif
 231         default:
 232                 /* need to add code for these */
 233                 break;
 234         }
 235
 236         if (info->clk)
 237                 clk_disable_unprepare(info->clk);
 238         kfree(info);
 239         return 0;
 240 }
 241
 242 /*
 243  * A few common types, add more as needed.
 244  */
 245 static struct of_device_id of_platform_serial_table[] = {
 246         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 247         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 248         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 249         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 250         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 251         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 252         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 253         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 254         { .compatible = "altr,16550-FIFO32",
 255                 .data = (void *)PORT_ALTR_16550_F32, },
 256         { .compatible = "altr,16550-FIFO64",
 257                 .data = (void *)PORT_ALTR_16550_F64, },
 258         { .compatible = "altr,16550-FIFO128",
 259                 .data = (void *)PORT_ALTR_16550_F128, },
 260 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 261         { .compatible = "ibm,qpace-nwp-serial",
 262                 .data = (void *)PORT_NWPSERIAL, },
 263 #endif
 264         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 265         { /* end of list */ },
 266 };
 267
 268 static struct platform_driver of_platform_serial_driver = {
 269         .driver = {
 270                 .name = "of_serial",
 271                 .owner = THIS_MODULE,
 272                 .of_match_table = of_platform_serial_table,
 273         },
 274         .probe = of_platform_serial_probe,
 275         .remove = of_platform_serial_remove,
 276 };
 277
 278 module_platform_driver(of_platform_serial_driver);
 279
 280 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 281 MODULE_LICENSE("GPL");
 282 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");