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                         if (prop >= port->mapsize) {
  88                                 dev_warn(&ofdev->dev, "reg-offset %u exceeds region size %pa\n",
  89                                          prop, &port->mapsize);
  90                                 ret = -EINVAL;
  91                                 goto err_unprepare;
  92                         }
  93
  94                         port->mapbase += prop;
  95                         port->mapsize -= prop;
  96                 }
  97
  98                 port->iotype = UPIO_MEM;
  99                 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
 100                         switch (prop) {
 101                         case 1:
 102                                 port->iotype = UPIO_MEM;
 103                                 break;
 104                         case 2:
 105                                 port->iotype = UPIO_MEM16;
 106                                 break;
 107                         case 4:
 108                                 port->iotype = of_device_is_big_endian(np) ?
 109                                                UPIO_MEM32BE : UPIO_MEM32;
 110                                 break;
 111                         default:
 112                                 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
 113                                          prop);
 114                                 ret = -EINVAL;
 115                                 goto err_unprepare;
 116                         }
 117                 }
 118                 port->flags |= UPF_IOREMAP;
 119         }
 120
 121         /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
 122         if (of_device_is_compatible(np, "mrvl,mmp-uart"))
 123                 port->regshift = 2;
 124
 125         /* Check for registers offset within the devices address range */
 126         if (of_property_read_u32(np, "reg-shift", &prop) == 0)
 127                 port->regshift = prop;
 128
 129         /* Check for fifo size */
 130         if (of_property_read_u32(np, "fifo-size", &prop) == 0)
 131                 port->fifosize = prop;
 132
 133         /* Check for a fixed line number */
 134         ret = of_alias_get_id(np, "serial");
 135         if (ret >= 0)
 136                 port->line = ret;
 137
 138         irq = of_irq_get(np, 0);
 139         if (irq < 0) {
 140                 if (irq == -EPROBE_DEFER) {
 141                         ret = -EPROBE_DEFER;
 142                         goto err_unprepare;
 143                 }
 144                 /* IRQ support not mandatory */
 145                 irq = 0;
 146         }
 147
 148         port->irq = irq;
 149
 150         info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL);
 151         if (IS_ERR(info->rst)) {
 152                 ret = PTR_ERR(info->rst);
 153                 goto err_unprepare;
 154         }
 155
 156         ret = reset_control_deassert(info->rst);
 157         if (ret)
 158                 goto err_unprepare;
 159
 160         port->type = type;
 161         port->uartclk = clk;
 162
 163         if (of_property_read_bool(np, "no-loopback-test"))
 164                 port->flags |= UPF_SKIP_TEST;
 165
 166         port->dev = &ofdev->dev;
 167         port->rs485_config = serial8250_em485_config;
 168         up->rs485_start_tx = serial8250_em485_start_tx;
 169         up->rs485_stop_tx = serial8250_em485_stop_tx;
 170
 171         switch (type) {
 172         case PORT_RT2880:
 173                 port->iotype = UPIO_AU;
 174                 break;
 175         }
 176
 177         if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
 178             (of_device_is_compatible(np, "fsl,ns16550") ||
 179              of_device_is_compatible(np, "fsl,16550-FIFO64"))) {
 180                 port->handle_irq = fsl8250_handle_irq;
 181                 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
 182         }
 183
 184         return 0;
 185 err_unprepare:
 186         clk_disable_unprepare(info->clk);
 187 err_pmruntime:
 188         pm_runtime_put_sync(&ofdev->dev);
 189         pm_runtime_disable(&ofdev->dev);
 190         return ret;
 191 }
 192
 193 /*
 194  * Try to register a serial port
 195  */
 196 static int of_platform_serial_probe(struct platform_device *ofdev)
 197 {
 198         struct of_serial_info *info;
 199         struct uart_8250_port port8250;
 200         unsigned int port_type;
 201         u32 tx_threshold;
 202         int ret;
 203
 204         port_type = (unsigned long)of_device_get_match_data(&ofdev->dev);
 205         if (port_type == PORT_UNKNOWN)
 206                 return -EINVAL;
 207
 208         if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas"))
 209                 return -EBUSY;
 210
 211         info = kzalloc(sizeof(*info), GFP_KERNEL);
 212         if (info == NULL)
 213                 return -ENOMEM;
 214
 215         memset(&port8250, 0, sizeof(port8250));
 216         ret = of_platform_serial_setup(ofdev, port_type, &port8250, info);
 217         if (ret)
 218                 goto err_free;
 219
 220         if (port8250.port.fifosize)
 221                 port8250.capabilities = UART_CAP_FIFO;
 222
 223         /* Check for TX FIFO threshold & set tx_loadsz */
 224         if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold",
 225                                   &tx_threshold) == 0) &&
 226             (tx_threshold < port8250.port.fifosize))
 227                 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold;
 228
 229         if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control"))
 230                 port8250.capabilities |= UART_CAP_AFE;
 231
 232         if (of_property_read_u32(ofdev->dev.of_node,
 233                         "overrun-throttle-ms",
 234                         &port8250.overrun_backoff_time_ms) != 0)
 235                 port8250.overrun_backoff_time_ms = 0;
 236
 237         ret = serial8250_register_8250_port(&port8250);
 238         if (ret < 0)
 239                 goto err_dispose;
 240
 241         info->type = port_type;
 242         info->line = ret;
 243         platform_set_drvdata(ofdev, info);
 244         return 0;
 245 err_dispose:
 246         irq_dispose_mapping(port8250.port.irq);
 247         pm_runtime_put_sync(&ofdev->dev);
 248         pm_runtime_disable(&ofdev->dev);
 249         clk_disable_unprepare(info->clk);
 250 err_free:
 251         kfree(info);
 252         return ret;
 253 }
 254
 255 /*
 256  * Release a line
 257  */
 258 static int of_platform_serial_remove(struct platform_device *ofdev)
 259 {
 260         struct of_serial_info *info = platform_get_drvdata(ofdev);
 261
 262         serial8250_unregister_port(info->line);
 263
 264         reset_control_assert(info->rst);
 265         pm_runtime_put_sync(&ofdev->dev);
 266         pm_runtime_disable(&ofdev->dev);
 267         clk_disable_unprepare(info->clk);
 268         kfree(info);
 269         return 0;
 270 }
 271
 272 #ifdef CONFIG_PM_SLEEP
 273 static int of_serial_suspend(struct device *dev)
 274 {
 275         struct of_serial_info *info = dev_get_drvdata(dev);
 276         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 277         struct uart_port *port = &port8250->port;
 278
 279         serial8250_suspend_port(info->line);
 280
 281         if (!uart_console(port) || console_suspend_enabled) {
 282                 pm_runtime_put_sync(dev);
 283                 clk_disable_unprepare(info->clk);
 284         }
 285         return 0;
 286 }
 287
 288 static int of_serial_resume(struct device *dev)
 289 {
 290         struct of_serial_info *info = dev_get_drvdata(dev);
 291         struct uart_8250_port *port8250 = serial8250_get_port(info->line);
 292         struct uart_port *port = &port8250->port;
 293
 294         if (!uart_console(port) || console_suspend_enabled) {
 295                 pm_runtime_get_sync(dev);
 296                 clk_prepare_enable(info->clk);
 297         }
 298
 299         serial8250_resume_port(info->line);
 300
 301         return 0;
 302 }
 303 #endif
 304 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
 305
 306 /*
 307  * A few common types, add more as needed.
 308  */
 309 static const struct of_device_id of_platform_serial_table[] = {
 310         { .compatible = "ns8250",   .data = (void *)PORT_8250, },
 311         { .compatible = "ns16450",  .data = (void *)PORT_16450, },
 312         { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
 313         { .compatible = "ns16550",  .data = (void *)PORT_16550, },
 314         { .compatible = "ns16750",  .data = (void *)PORT_16750, },
 315         { .compatible = "ns16850",  .data = (void *)PORT_16850, },
 316         { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
 317         { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
 318         { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, },
 319         { .compatible = "altr,16550-FIFO32",
 320                 .data = (void *)PORT_ALTR_16550_F32, },
 321         { .compatible = "altr,16550-FIFO64",
 322                 .data = (void *)PORT_ALTR_16550_F64, },
 323         { .compatible = "altr,16550-FIFO128",
 324                 .data = (void *)PORT_ALTR_16550_F128, },
 325         { .compatible = "mediatek,mtk-btif",
 326                 .data = (void *)PORT_MTK_BTIF, },
 327         { .compatible = "mrvl,mmp-uart",
 328                 .data = (void *)PORT_XSCALE, },
 329         { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, },
 330         { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, },
 331         { /* end of list */ },
 332 };
 333 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
 334
 335 static struct platform_driver of_platform_serial_driver = {
 336         .driver = {
 337                 .name = "of_serial",
 338                 .of_match_table = of_platform_serial_table,
 339                 .pm = &of_serial_pm_ops,
 340         },
 341         .probe = of_platform_serial_probe,
 342         .remove = of_platform_serial_remove,
 343 };
 344
 345 module_platform_driver(of_platform_serial_driver);
 346
 347 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 348 MODULE_LICENSE("GPL");
 349 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");