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
   8 #include <linux/bits.h>
   9 #include <linux/console.h>
  10 #include <linux/math.h>
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/serial_core.h>
  14 #include <linux/serial_reg.h>
  15 #include <linux/of_address.h>
  16 #include <linux/of_irq.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/pm_runtime.h>
  19 #include <linux/clk.h>
  20 #include <linux/reset.h>
  21
  22 #include "8250.h"
  23
  24 struct of_serial_info {
  25         struct clk *clk;
  26         struct reset_control *rst;
  27         int type;
  28         int line;
  29 };
  30
  31 /* Nuvoton NPCM timeout register */
  32 #define UART_NPCM_TOR          7
  33 #define UART_NPCM_TOIE         BIT(7)  /* Timeout Interrupt Enable */
  34
  35 static int npcm_startup(struct uart_port *port)
  36 {
  37         /*
  38          * Nuvoton calls the scratch register 'UART_TOR' (timeout
  39          * register). Enable it, and set TIOC (timeout interrupt
  40          * comparator) to be 0x20 for correct operation.
  41          */
  42         serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
  43
  44         return serial8250_do_startup(port);
  45 }
  46
  47 /* Nuvoton NPCM UARTs have a custom divisor calculation */
  48 static unsigned int npcm_get_divisor(struct uart_port *port, unsigned int baud,
  49                                      unsigned int *frac)
  50 {
  51         return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
  52 }
  53
  54 static int npcm_setup(struct uart_port *port)
  55 {
  56         port->get_divisor = npcm_get_divisor;
  57         port->startup = npcm_startup;
  58         return 0;
  59 }
  60
  61 /*
  62  * Fill a struct uart_port for a given device node
  63  */
  64 static int of_platform_serial_setup(struct platform_device *ofdev,
  65                         int type, struct uart_8250_port *up,
  66                         struct of_serial_info *info)
  67 {
  68         struct resource resource;
  69         struct device *dev = &ofdev->dev;
  70         struct device_node *np = dev->of_node;
  71         struct uart_port *port = &up->port;
  72         u32 clk, spd, prop;
  73         int ret, irq;
  74
  75         memset(port, 0, sizeof *port);
  76
  77         pm_runtime_enable(&ofdev->dev);
  78         pm_runtime_get_sync(&ofdev->dev);
  79
  80         if (of_property_read_u32(np, "clock-frequency", &clk)) {
  81
  82                 /* Get clk rate through clk driver if present */
  83                 info->clk = devm_clk_get_enabled(dev, NULL);
  84                 if (IS_ERR(info->clk)) {
  85                         ret = dev_err_probe(dev, PTR_ERR(info->clk), "failed to get clock\n");
  86                         goto err_pmruntime;
  87                 }
  88
  89                 clk = clk_get_rate(info->clk);
  90         }
  91         /* If current-speed was set, then try not to change it. */
  92         if (of_property_read_u32(np, "current-speed", &spd) == 0)
  93                 port->custom_divisor = clk / (16 * spd);
  94
  95         ret = of_address_to_resource(np, 0, &resource);
  96         if (ret) {
  97                 dev_err_probe(dev, ret, "invalid address\n");
  98                 goto err_pmruntime;
  99         }
 100
 101         port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT |
 102                                   UPF_FIXED_TYPE;
 103         spin_lock_init(&port->lock);
 104
 105         if (resource_type(&resource) == IORESOURCE_IO) {
 106                 port->iotype = UPIO_PORT;
 107                 port->iobase = resource.start;
 108         } else {
 109                 port->mapbase = resource.start;
 110                 port->mapsize = resource_size(&resource);
 111
 112                 /* Check for shifted address mapping */
 113                 if (of_property_read_u32(np, "reg-offset", &prop) == 0) {
 114                         if (prop >= port->mapsize) {
 115                                 ret = dev_err_probe(dev, -EINVAL, "reg-offset %u exceeds region size %pa\n",
 116                                                     prop, &port->mapsize);
 117                                 goto err_pmruntime;
 118                         }
 119
 120                         port->mapbase += prop;
 121                         port->mapsize -= prop;
 122                 }
 123
 124                 port->iotype = UPIO_MEM;
 125                 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 126                         switch (prop) {
 127                         case 1:
 128                                 port->iotype = UPIO_MEM;
 129                                 break;
 130                         case 2:
 131                                 port->iotype = UPIO_MEM16;
 132                                 break;
 133                         case 4:
 134                                 port->iotype = of_device_is_big_endian(np) ?
 135                                                UPIO_MEM32BE : UPIO_MEM32;
 136                                 break;
 137                         default:
 138                                 ret = dev_err_probe(dev, -EINVAL, "unsupported reg-io-width (%u)\n",
 139                                                     prop);
 140                                 goto err_pmruntime;
 141                         }
 142                 }
 143                 port->flags |= UPF_IOREMAP;
 144         }
 145
 146         /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
 147         if (of_device_is_compatible(np, "mrvl,mmp-uart"))
 148                 port->regshift = 2;
 149
 150         /* Check for registers offset within the devices address range */
 151         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 152                 port->regshift = prop;
 153
 154         /* Check for fifo size */
 155         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 156                 port->fifosize = prop;
 157
 158         /* Check for a fixed line number */
 159         ret = of_alias_get_id(np, "serial");
 160         if (ret >= 0)
 161                 port->line = ret;
 162
 163         irq = of_irq_get(np, 0);
 164         if (irq < 0) {
 165                 if (irq == -EPROBE_DEFER) {
 166                         ret = -EPROBE_DEFER;
 167                         goto err_pmruntime;
 168                 }
 169                 /* IRQ support not mandatory */
 170                 irq = 0;
 171         }
 172
 173         port->irq = irq;
 174
 175         info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 176         if (IS_ERR(info->rst)) {
 177                 ret = PTR_ERR(info->rst);
 178                 goto err_pmruntime;
 179         }
 180
 181         ret = reset_control_deassert(info->rst);
 182         if (ret)
 183                 goto err_pmruntime;
 184
 185         port->type = type;
 186         port->uartclk = clk;
 187
 188         if (of_property_read_bool(np, "no-loopback-test"))
 189                 port->flags |= UPF_SKIP_TEST;
 190
 191         port->dev = &ofdev->dev;
 192         port->rs485_config = serial8250_em485_config;
 193         port->rs485_supported = serial8250_em485_supported;
 194         up->rs485_start_tx = serial8250_em485_start_tx;
 195         up->rs485_stop_tx = serial8250_em485_stop_tx;
 196
 197         switch (type) {
 198         case PORT_RT2880:
 199                 ret = rt288x_setup(port);
 200                 break;
 201         case PORT_NPCM:
 202                 ret = npcm_setup(port);
 203                 break;
 204         default:
 205                 /* Nothing to do */
 206                 ret = 0;
 207                 break;
 208         }
 209         if (ret)
 210                 goto err_pmruntime;
 211
 212         if (IS_REACHABLE(CONFIG_SERIAL_8250_FSL) &&
 213             (of_device_is_compatible(np, "fsl,ns16550") ||
 214              of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
 215                 port->handle_irq = fsl8250_handle_irq;
 216                 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
 217         }
 218
 219         return 0;
 220 err_pmruntime:
 221         pm_runtime_put_sync(&ofdev->dev);
 222         pm_runtime_disable(&ofdev->dev);
 223         return ret;
 224 }
 225
 226 /*
 227  * Try to register a serial port
 228  */
 229 static int of_platform_serial_probe(struct platform_device *ofdev)
 230 {
 231         struct of_serial_info *info;
 232         struct uart_8250_port port8250;
 233         unsigned int port_type;
 234         u32 tx_threshold;
 235         int ret;
 236
 237         if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) &&
 238             of_device_is_compatible(ofdev->dev.of_node, "brcm,bcm7271-uart"))
 239                 return -ENODEV;
 240
 241         port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
 242         if (port_type == PORT_UNKNOWN)
 243                 return -EINVAL;
 244
 245         if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
 246                 return -EBUSY;
 247
 248         info = kzalloc(sizeof(*info), GFP_KERNEL);
 249         if (info == NULL)
 250                 return -ENOMEM;
 251
 252         memset(&port8250, 0, sizeof(port8250));
 253         ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
 254         if (ret)
 255                 goto err_free;
 256
 257         if (port8250.port.fifosize)
 258                 port8250.capabilities = UART_CAP_FIFO;
 259
 260         /* Check for TX FIFO threshold & set tx_loadsz */
 261         if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
 262                                   &tx_threshold) == 0) &&
 263             (tx_threshold < port8250.port.fifosize))
 264                 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
 265
 266         if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
 267                 port8250.capabilities |= UART_CAP_AFE;
 268
 269         if (of_property_read_u32(ofdev->dev.of_node,
 270                         "overrun-throttle-ms",
 271                         &port8250.overrun_backoff_time_ms) != 0)
 272                 port8250.overrun_backoff_time_ms = 0;
 273
 274         ret = serial8250_register_8250_port(&port8250);
 275         if (ret < 0)
 276                 goto err_dispose;
 277
 278         info->type = port_type;
 279         info->line = ret;
 280         platform_set_drvdata(ofdev, info);
 281         return 0;
 282 err_dispose:
 283         irq_dispose_mapping(port8250.port.irq);
 284         pm_runtime_put_sync(&ofdev->dev);
 285         pm_runtime_disable(&ofdev->dev);
 286 err_free:
 287         kfree(info);
 288         return ret;
 289 }
 290
 291 /*
 292  * Release a line
 293  */
 294 static void of_platform_serial_remove(struct platform_device *ofdev)
 295 {
 296         struct of_serial_info *info = platform_get_drvdata(ofdev);
 297
 298         serial8250_unregister_port(info->line);
 299
 300         reset_control_assert(info->rst);
 301         pm_runtime_put_sync(&ofdev->dev);
 302         pm_runtime_disable(&ofdev->dev);
 303         kfree(info);
 304 }
 305
 306 #ifdef CONFIG_PM_SLEEP
 307 static int of_serial_suspend(struct device *dev)
 308 {
 309         struct of_serial_info *info = dev_get_drvdata(dev);
 310         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 311         struct uart_port *port = &port8250->port;
 312
 313         serial8250_suspend_port(info->line);
 314
 315         if (!uart_console(port) || console_suspend_enabled) {
 316                 pm_runtime_put_sync(dev);
 317                 clk_disable_unprepare(info->clk);
 318         }
 319         return 0;
 320 }
 321
 322 static int of_serial_resume(struct device *dev)
 323 {
 324         struct of_serial_info *info = dev_get_drvdata(dev);
 325         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 326         struct uart_port *port = &port8250->port;
 327
 328         if (!uart_console(port) || console_suspend_enabled) {
 329                 pm_runtime_get_sync(dev);
 330                 clk_prepare_enable(info->clk);
 331         }
 332
 333         serial8250_resume_port(info->line);
 334
 335         return 0;
 336 }
 337 #endif
 338 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 339
 340 /*
 341  * A few common types, add more as needed.
 342  */
 343 static const struct of_device_id of_platform_serial_table[] = {
 344         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 345         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 346         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 347         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 348         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 349         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 350         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 351         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 352         { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
 353         { .compatible = "altr,16550-FIFO32",
 354                 .data = (void *)PORT_ALTR_16550_F32, },
 355         { .compatible = "altr,16550-FIFO64",
 356                 .data = (void *)PORT_ALTR_16550_F64, },
 357         { .compatible = "altr,16550-FIFO128",
 358                 .data = (void *)PORT_ALTR_16550_F128, },
 359         { .compatible = "fsl,16550-FIFO64",
 360                 .data = (void *)PORT_16550A_FSL64, },
 361         { .compatible = "mediatek,mtk-btif",
 362                 .data = (void *)PORT_MTK_BTIF, },
 363         { .compatible = "mrvl,mmp-uart",
 364                 .data = (void *)PORT_XSCALE, },
 365         { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
 366         { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, },
 367         { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
 368         { /* end of list */ },
 369 };
 370 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
 371
 372 static struct platform_driver of_platform_serial_driver = {
 373         .driver = {
 374                 .name = "of_serial",
 375                 .of_match_table = of_platform_serial_table,
 376                 .pm = &of_serial_pm_ops,
 377         },
 378         .probe = of_platform_serial_probe,
 379         .remove_new = of_platform_serial_remove,
 380 };
 381
 382 module_platform_driver(of_platform_serial_driver);
 383
 384 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 385 MODULE_LICENSE("GPL");
 386 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");