drivers/tty/serial/8250/8250_of.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Serial Port driver for Open Firmware platform devices
   4  *
   5  *    Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp.
   6  */
   7 #include <linux/console.h>
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/serial_core.h>
  11 #include <linux/serial_reg.h>
  12 #include <linux/of_address.h>
  13 #include <linux/of_irq.h>
  14 #include <linux/of_platform.h>
  15 #include <linux/pm_runtime.h>
  16 #include <linux/clk.h>
  17 #include <linux/reset.h>
  18
  19 #include "8250.h"
  20
  21 struct of_serial_info {
  22         struct clk *clk;
  23         struct reset_control *rst;
  24         int type;
  25         int line;
  26 };
  27
  28 /*
  29  * Fill a struct uart_port for a given device node
  30  */
  31 static int of_platform_serial_setup(struct platform_device *ofdev,
  32                         int type, struct uart_8250_port *up,
  33                         struct of_serial_info *info)
  34 {
  35         struct resource resource;
  36         struct device_node *np = ofdev->dev.of_node;
  37         struct uart_port *port = &up->port;
  38         u32 clk, spd, prop;
  39         int ret, irq;
  40
  41         memset(port, 0, sizeof *port);
  42
  43         pm_runtime_enable(&ofdev->dev);
  44         pm_runtime_get_sync(&ofdev->dev);
  45
  46         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  47
  48                 /* Get clk rate through clk driver if present */
  49                 info->clk = devm_clk_get(&ofdev->dev, NULL);
  50                 if (IS_ERR(info->clk)) {
  51                         ret = PTR_ERR(info->clk);
  52                         if (ret != -EPROBE_DEFER)
  53                                 dev_warn(&ofdev->dev,
  54                                          "failed to get clock: %d\n", ret);
  55                         goto err_pmruntime;
  56                 }
  57
  58                 ret = clk_prepare_enable(info->clk);
  59                 if (ret < 0)
  60                         goto err_pmruntime;
  61
  62                 clk = clk_get_rate(info->clk);
  63         }
  64         /* If current-speed was set, then try not to change it. */
  65         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  66                 port->custom_divisor = clk / (16 * spd);
  67
  68         ret = of_address_to_resource(np, 0, &resource);
  69         if (ret) {
  70                 dev_warn(&ofdev->dev, "invalid address\n");
  71                 goto err_unprepare;
  72         }
  73
  74         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
  75                                   UPF_FIXED_TYPE;
  76         spin_lock_init(&port->lock);
  77
  78         if (resource_type(&resource) == IORESOURCE_IO) {
  79                 port->iotype = UPIO_PORT;
  80                 port->iobase = resource.start;
  81         } else {
  82                 port->mapbase = resource.start;
  83                 port->mapsize = resource_size(&resource);
  84
  85                 /* Check for shifted address mapping */
  86                 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
  87                         port->mapbase += prop;
  88
  89                 port->iotype = UPIO_MEM;
  90                 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
  91                         switch (prop) {
  92                         case 1:
  93                                 port->iotype = UPIO_MEM;
  94                                 break;
  95                         case 2:
  96                                 port->iotype = UPIO_MEM16;
  97                                 break;
  98                         case 4:
  99                                 port->iotype = of_device_is_big_endian(np) ?
 100                                                UPIO_MEM32BE : UPIO_MEM32;
 101                                 break;
 102                         default:
 103                                 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 104                                          prop);
 105                                 ret = -EINVAL;
 106                                 goto err_unprepare;
 107                         }
 108                 }
 109                 port->flags |= UPF_IOREMAP;
 110         }
 111
 112         /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
 113         if (of_device_is_compatible(np, "mrvl,mmp-uart"))
 114                 port->regshift = 2;
 115
 116         /* Check for registers offset within the devices address range */
 117         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 118                 port->regshift = prop;
 119
 120         /* Check for fifo size */
 121         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 122                 port->fifosize = prop;
 123
 124         /* Check for a fixed line number */
 125         ret = of_alias_get_id(np, "serial");
 126         if (ret >= 0)
 127                 port->line = ret;
 128
 129         irq = of_irq_get(np, 0);
 130         if (irq < 0) {
 131                 if (irq == -EPROBE_DEFER) {
 132                         ret = -EPROBE_DEFER;
 133                         goto err_unprepare;
 134                 }
 135                 /* IRQ support not mandatory */
 136                 irq = 0;
 137         }
 138
 139         port->irq = irq;
 140
 141         info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 142         if (IS_ERR(info->rst)) {
 143                 ret = PTR_ERR(info->rst);
 144                 goto err_unprepare;
 145         }
 146
 147         ret = reset_control_deassert(info->rst);
 148         if (ret)
 149                 goto err_unprepare;
 150
 151         port->type = type;
 152         port->uartclk = clk;
 153
 154         if (of_property_read_bool(np, "no-loopback-test"))
 155                 port->flags |= UPF_SKIP_TEST;
 156
 157         port->dev = &ofdev->dev;
 158         port->rs485_config = serial8250_em485_config;
 159         up->rs485_start_tx = serial8250_em485_start_tx;
 160         up->rs485_stop_tx = serial8250_em485_stop_tx;
 161
 162         switch (type) {
 163         case PORT_RT2880:
 164                 port->iotype = UPIO_AU;
 165                 break;
 166         }
 167
 168         if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
 169             (of_device_is_compatible(np, "fsl,ns16550") ||
 170              of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
 171                 port->handle_irq = fsl8250_handle_irq;
 172                 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
 173         }
 174
 175         return 0;
 176 err_unprepare:
 177         clk_disable_unprepare(info->clk);
 178 err_pmruntime:
 179         pm_runtime_put_sync(&ofdev->dev);
 180         pm_runtime_disable(&ofdev->dev);
 181         return ret;
 182 }
 183
 184 /*
 185  * Try to register a serial port
 186  */
 187 static int of_platform_serial_probe(struct platform_device *ofdev)
 188 {
 189         struct of_serial_info *info;
 190         struct uart_8250_port port8250;
 191         unsigned int port_type;
 192         u32 tx_threshold;
 193         int ret;
 194
 195         port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
 196         if (port_type == PORT_UNKNOWN)
 197                 return -EINVAL;
 198
 199         if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
 200                 return -EBUSY;
 201
 202         info = kzalloc(sizeof(*info), GFP_KERNEL);
 203         if (info == NULL)
 204                 return -ENOMEM;
 205
 206         memset(&port8250, 0, sizeof(port8250));
 207         ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
 208         if (ret)
 209                 goto err_free;
 210
 211         if (port8250.port.fifosize)
 212                 port8250.capabilities = UART_CAP_FIFO;
 213
 214         /* Check for TX FIFO threshold & set tx_loadsz */
 215         if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
 216                                   &tx_threshold) == 0) &&
 217             (tx_threshold < port8250.port.fifosize))
 218                 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
 219
 220         if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
 221                 port8250.capabilities |= UART_CAP_AFE;
 222
 223         if (of_property_read_u32(ofdev->dev.of_node,
 224                         "overrun-throttle-ms",
 225                         &port8250.overrun_backoff_time_ms) != 0)
 226                 port8250.overrun_backoff_time_ms = 0;
 227
 228         ret = serial8250_register_8250_port(&port8250);
 229         if (ret < 0)
 230                 goto err_dispose;
 231
 232         info->type = port_type;
 233         info->line = ret;
 234         platform_set_drvdata(ofdev, info);
 235         return 0;
 236 err_dispose:
 237         irq_dispose_mapping(port8250.port.irq);
 238         pm_runtime_put_sync(&ofdev->dev);
 239         pm_runtime_disable(&ofdev->dev);
 240         clk_disable_unprepare(info->clk);
 241 err_free:
 242         kfree(info);
 243         return ret;
 244 }
 245
 246 /*
 247  * Release a line
 248  */
 249 static int of_platform_serial_remove(struct platform_device *ofdev)
 250 {
 251         struct of_serial_info *info = platform_get_drvdata(ofdev);
 252
 253         serial8250_unregister_port(info->line);
 254
 255         reset_control_assert(info->rst);
 256         pm_runtime_put_sync(&ofdev->dev);
 257         pm_runtime_disable(&ofdev->dev);
 258         clk_disable_unprepare(info->clk);
 259         kfree(info);
 260         return 0;
 261 }
 262
 263 #ifdef CONFIG_PM_SLEEP
 264 static int of_serial_suspend(struct device *dev)
 265 {
 266         struct of_serial_info *info = dev_get_drvdata(dev);
 267         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 268         struct uart_port *port = &port8250->port;
 269
 270         serial8250_suspend_port(info->line);
 271
 272         if (!uart_console(port) || console_suspend_enabled) {
 273                 pm_runtime_put_sync(dev);
 274                 clk_disable_unprepare(info->clk);
 275         }
 276         return 0;
 277 }
 278
 279 static int of_serial_resume(struct device *dev)
 280 {
 281         struct of_serial_info *info = dev_get_drvdata(dev);
 282         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 283         struct uart_port *port = &port8250->port;
 284
 285         if (!uart_console(port) || console_suspend_enabled) {
 286                 pm_runtime_get_sync(dev);
 287                 clk_prepare_enable(info->clk);
 288         }
 289
 290         serial8250_resume_port(info->line);
 291
 292         return 0;
 293 }
 294 #endif
 295 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 296
 297 /*
 298  * A few common types, add more as needed.
 299  */
 300 static const struct of_device_id of_platform_serial_table[] = {
 301         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 302         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 303         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 304         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 305         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 306         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 307         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 308         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 309         { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
 310         { .compatible = "altr,16550-FIFO32",
 311                 .data = (void *)PORT_ALTR_16550_F32, },
 312         { .compatible = "altr,16550-FIFO64",
 313                 .data = (void *)PORT_ALTR_16550_F64, },
 314         { .compatible = "altr,16550-FIFO128",
 315                 .data = (void *)PORT_ALTR_16550_F128, },
 316         { .compatible = "mediatek,mtk-btif",
 317                 .data = (void *)PORT_MTK_BTIF, },
 318         { .compatible = "mrvl,mmp-uart",
 319                 .data = (void *)PORT_XSCALE, },
 320         { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
 321         { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
 322         { /* end of list */ },
 323 };
 324 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
 325
 326 static struct platform_driver of_platform_serial_driver = {
 327         .driver = {
 328                 .name = "of_serial",
 329                 .of_match_table = of_platform_serial_table,
 330                 .pm = &of_serial_pm_ops,
 331         },
 332         .probe = of_platform_serial_probe,
 333         .remove = of_platform_serial_remove,
 334 };
 335
 336 module_platform_driver(of_platform_serial_driver);
 337
 338 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 339 MODULE_LICENSE("GPL");
 340 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");