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_8250.h>
  18 #include <linux/serial_reg.h>
  19 #include <linux/of_address.h>
  20 #include <linux/of_irq.h>
  21 #include <linux/of_platform.h>
  22 #include <linux/nwpserial.h>
  23 #include <linux/clk.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         port->irq = irq_of_parse_and_map(np, 0);
 101         port->iotype = UPIO_MEM;
 102         if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 103                 switch (prop) {
 104                 case 1:
 105                         port->iotype = UPIO_MEM;
 106                         break;
 107                 case 4:
 108                         port->iotype = UPIO_MEM32;
 109                         break;
 110                 default:
 111                         dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 112                                  prop);
 113                         ret = -EINVAL;
 114                         goto out;
 115                 }
 116         }
 117
 118         port->type = type;
 119         port->uartclk = clk;
 120         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
 121                 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 122
 123         if (of_find_property(np, "no-loopback-test", NULL))
 124                 port->flags |= UPF_SKIP_TEST;
 125
 126         port->dev = &ofdev->dev;
 127
 128         if (type == PORT_TEGRA)
 129                 port->handle_break = tegra_serial_handle_break;
 130
 131         return 0;
 132 out:
 133         if (info->clk)
 134                 clk_disable_unprepare(info->clk);
 135         return ret;
 136 }
 137
 138 /*
 139  * Try to register a serial port
 140  */
 141 static struct of_device_id of_platform_serial_table[];
 142 static int of_platform_serial_probe(struct platform_device *ofdev)
 143 {
 144         const struct of_device_id *match;
 145         struct of_serial_info *info;
 146         struct uart_port port;
 147         int port_type;
 148         int ret;
 149
 150         match = of_match_device(of_platform_serial_table, &ofdev->dev);
 151         if (!match)
 152                 return -EINVAL;
 153
 154         if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
 155                 return -EBUSY;
 156
 157         info = kmalloc(sizeof(*info), GFP_KERNEL);
 158         if (info == NULL)
 159                 return -ENOMEM;
 160
 161         port_type = (unsigned long)match->data;
 162         ret = of_platform_serial_setup(ofdev, port_type, &port, info);
 163         if (ret)
 164                 goto out;
 165
 166         switch (port_type) {
 167 #ifdef CONFIG_SERIAL_8250
 168         case PORT_8250 ... PORT_MAX_8250:
 169         {
 170                 /* For now the of bindings don't support the extra
 171                    8250 specific bits */
 172                 struct uart_8250_port port8250;
 173                 memset(&port8250, 0, sizeof(port8250));
 174                 port8250.port = port;
 175                 ret = serial8250_register_8250_port(&port8250);
 176                 break;
 177         }
 178 #endif
 179 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 180         case PORT_NWPSERIAL:
 181                 ret = nwpserial_register_port(&port);
 182                 break;
 183 #endif
 184         default:
 185                 /* need to add code for these */
 186         case PORT_UNKNOWN:
 187                 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
 188                 ret = -ENODEV;
 189                 break;
 190         }
 191         if (ret < 0)
 192                 goto out;
 193
 194         info->type = port_type;
 195         info->line = ret;
 196         dev_set_drvdata(&ofdev->dev, info);
 197         return 0;
 198 out:
 199         kfree(info);
 200         irq_dispose_mapping(port.irq);
 201         return ret;
 202 }
 203
 204 /*
 205  * Release a line
 206  */
 207 static int of_platform_serial_remove(struct platform_device *ofdev)
 208 {
 209         struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
 210         switch (info->type) {
 211 #ifdef CONFIG_SERIAL_8250
 212         case PORT_8250 ... PORT_MAX_8250:
 213                 serial8250_unregister_port(info->line);
 214                 break;
 215 #endif
 216 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 217         case PORT_NWPSERIAL:
 218                 nwpserial_unregister_port(info->line);
 219                 break;
 220 #endif
 221         default:
 222                 /* need to add code for these */
 223                 break;
 224         }
 225
 226         if (info->clk)
 227                 clk_disable_unprepare(info->clk);
 228         kfree(info);
 229         return 0;
 230 }
 231
 232 /*
 233  * A few common types, add more as needed.
 234  */
 235 static struct of_device_id of_platform_serial_table[] = {
 236         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 237         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 238         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 239         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 240         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 241         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 242         { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
 243         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 244 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
 245         { .compatible = "ibm,qpace-nwp-serial",
 246                 .data = (void *)PORT_NWPSERIAL, },
 247 #endif
 248         { .type = "serial",         .data = (void *)PORT_UNKNOWN, },
 249         { /* end of list */ },
 250 };
 251
 252 static struct platform_driver of_platform_serial_driver = {
 253         .driver = {
 254                 .name = "of_serial",
 255                 .owner = THIS_MODULE,
 256                 .of_match_table = of_platform_serial_table,
 257         },
 258         .probe = of_platform_serial_probe,
 259         .remove = of_platform_serial_remove,
 260 };
 261
 262 module_platform_driver(of_platform_serial_driver);
 263
 264 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 265 MODULE_LICENSE("GPL");
 266 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");