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/delay.h> 11 #include <linux/serial_core.h> 12 #include <linux/serial_reg.h> 13 #include <linux/of_address.h> 14 #include <linux/of_irq.h> 15 #include <linux/of_platform.h> 16 #include <linux/pm_runtime.h> 17 #include <linux/clk.h> 18 #include <linux/reset.h> 19 20 #include "8250.h" 21 22 struct of_serial_info { 23 struct clk *clk; 24 struct reset_control *rst; 25 int type; 26 int line; 27 }; 28 29 #ifdef CONFIG_ARCH_TEGRA 30 static void tegra_serial_handle_break(struct uart_port *p) 31 { 32 unsigned int status, tmout = 10000; 33 34 do { 35 status = p->serial_in(p, UART_LSR); 36 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) 37 status = p->serial_in(p, UART_RX); 38 else 39 break; 40 if (--tmout == 0) 41 break; 42 udelay(1); 43 } while (1); 44 } 45 #else 46 static inline void tegra_serial_handle_break(struct uart_port *port) 47 { 48 } 49 #endif 50 51 /* 52 * Fill a struct uart_port for a given device node 53 */ 54 static int of_platform_serial_setup(struct platform_device *ofdev, 55 int type, struct uart_port *port, 56 struct of_serial_info *info) 57 { 58 struct resource resource; 59 struct device_node *np = ofdev->dev.of_node; 60 u32 clk, spd, prop; 61 int ret, irq; 62 63 memset(port, 0, sizeof *port); 64 65 pm_runtime_enable(&ofdev->dev); 66 pm_runtime_get_sync(&ofdev->dev); 67 68 if (of_property_read_u32(np, "clock-frequency", &clk)) { 69 70 /* Get clk rate through clk driver if present */ 71 info->clk = devm_clk_get(&ofdev->dev, NULL); 72 if (IS_ERR(info->clk)) { 73 ret = PTR_ERR(info->clk); 74 if (ret != -EPROBE_DEFER) 75 dev_warn(&ofdev->dev, 76 "failed to get clock: %d\n", ret); 77 goto err_pmruntime; 78 } 79 80 ret = clk_prepare_enable(info->clk); 81 if (ret < 0) 82 goto err_pmruntime; 83 84 clk = clk_get_rate(info->clk); 85 } 86 /* If current-speed was set, then try not to change it. */ 87 if (of_property_read_u32(np, "current-speed", &spd) == 0) 88 port->custom_divisor = clk / (16 * spd); 89 90 ret = of_address_to_resource(np, 0, &resource); 91 if (ret) { 92 dev_warn(&ofdev->dev, "invalid address\n"); 93 goto err_unprepare; 94 } 95 96 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_FIXED_PORT | 97 UPF_FIXED_TYPE; 98 spin_lock_init(&port->lock); 99 100 if (resource_type(&resource) == IORESOURCE_IO) { 101 port->iotype = UPIO_PORT; 102 port->iobase = resource.start; 103 } else { 104 port->mapbase = resource.start; 105 port->mapsize = resource_size(&resource); 106 107 /* Check for shifted address mapping */ 108 if (of_property_read_u32(np, "reg-offset", &prop) == 0) 109 port->mapbase += prop; 110 111 port->iotype = UPIO_MEM; 112 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) { 113 switch (prop) { 114 case 1: 115 port->iotype = UPIO_MEM; 116 break; 117 case 2: 118 port->iotype = UPIO_MEM16; 119 break; 120 case 4: 121 port->iotype = of_device_is_big_endian(np) ? 122 UPIO_MEM32BE : UPIO_MEM32; 123 break; 124 default: 125 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n", 126 prop); 127 ret = -EINVAL; 128 goto err_unprepare; 129 } 130 } 131 port->flags |= UPF_IOREMAP; 132 } 133 134 /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */ 135 if (of_device_is_compatible(np, "mrvl,mmp-uart")) 136 port->regshift = 2; 137 138 /* Check for registers offset within the devices address range */ 139 if (of_property_read_u32(np, "reg-shift", &prop) == 0) 140 port->regshift = prop; 141 142 /* Check for fifo size */ 143 if (of_property_read_u32(np, "fifo-size", &prop) == 0) 144 port->fifosize = prop; 145 146 /* Check for a fixed line number */ 147 ret = of_alias_get_id(np, "serial"); 148 if (ret >= 0) 149 port->line = ret; 150 151 irq = of_irq_get(np, 0); 152 if (irq < 0) { 153 if (irq == -EPROBE_DEFER) { 154 ret = -EPROBE_DEFER; 155 goto err_unprepare; 156 } 157 /* IRQ support not mandatory */ 158 irq = 0; 159 } 160 161 port->irq = irq; 162 163 info->rst = devm_reset_control_get_optional_shared(&ofdev->dev, NULL); 164 if (IS_ERR(info->rst)) { 165 ret = PTR_ERR(info->rst); 166 goto err_unprepare; 167 } 168 169 ret = reset_control_deassert(info->rst); 170 if (ret) 171 goto err_unprepare; 172 173 port->type = type; 174 port->uartclk = clk; 175 port->irqflags |= IRQF_SHARED; 176 177 if (of_property_read_bool(np, "no-loopback-test")) 178 port->flags |= UPF_SKIP_TEST; 179 180 port->dev = &ofdev->dev; 181 182 switch (type) { 183 case PORT_TEGRA: 184 port->handle_break = tegra_serial_handle_break; 185 break; 186 187 case PORT_RT2880: 188 port->iotype = UPIO_AU; 189 break; 190 } 191 192 if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) && 193 (of_device_is_compatible(np, "fsl,ns16550") || 194 of_device_is_compatible(np, "fsl,16550-FIFO64"))) 195 port->handle_irq = fsl8250_handle_irq; 196 197 return 0; 198 err_unprepare: 199 clk_disable_unprepare(info->clk); 200 err_pmruntime: 201 pm_runtime_put_sync(&ofdev->dev); 202 pm_runtime_disable(&ofdev->dev); 203 return ret; 204 } 205 206 /* 207 * Try to register a serial port 208 */ 209 static int of_platform_serial_probe(struct platform_device *ofdev) 210 { 211 struct of_serial_info *info; 212 struct uart_8250_port port8250; 213 unsigned int port_type; 214 u32 tx_threshold; 215 int ret; 216 217 port_type = (unsigned long)of_device_get_match_data(&ofdev->dev); 218 if (port_type == PORT_UNKNOWN) 219 return -EINVAL; 220 221 if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas")) 222 return -EBUSY; 223 224 info = kzalloc(sizeof(*info), GFP_KERNEL); 225 if (info == NULL) 226 return -ENOMEM; 227 228 memset(&port8250, 0, sizeof(port8250)); 229 ret = of_platform_serial_setup(ofdev, port_type, &port8250.port, info); 230 if (ret) 231 goto err_free; 232 233 if (port8250.port.fifosize) 234 port8250.capabilities = UART_CAP_FIFO; 235 236 /* Check for TX FIFO threshold & set tx_loadsz */ 237 if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold", 238 &tx_threshold) == 0) && 239 (tx_threshold < port8250.port.fifosize)) 240 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold; 241 242 if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control")) 243 port8250.capabilities |= UART_CAP_AFE; 244 245 if (of_property_read_u32(ofdev->dev.of_node, 246 "overrun-throttle-ms", 247 &port8250.overrun_backoff_time_ms) != 0) 248 port8250.overrun_backoff_time_ms = 0; 249 250 ret = serial8250_register_8250_port(&port8250); 251 if (ret < 0) 252 goto err_dispose; 253 254 info->type = port_type; 255 info->line = ret; 256 platform_set_drvdata(ofdev, info); 257 return 0; 258 err_dispose: 259 irq_dispose_mapping(port8250.port.irq); 260 pm_runtime_put_sync(&ofdev->dev); 261 pm_runtime_disable(&ofdev->dev); 262 clk_disable_unprepare(info->clk); 263 err_free: 264 kfree(info); 265 return ret; 266 } 267 268 /* 269 * Release a line 270 */ 271 static int of_platform_serial_remove(struct platform_device *ofdev) 272 { 273 struct of_serial_info *info = platform_get_drvdata(ofdev); 274 275 serial8250_unregister_port(info->line); 276 277 reset_control_assert(info->rst); 278 pm_runtime_put_sync(&ofdev->dev); 279 pm_runtime_disable(&ofdev->dev); 280 clk_disable_unprepare(info->clk); 281 kfree(info); 282 return 0; 283 } 284 285 #ifdef CONFIG_PM_SLEEP 286 static int of_serial_suspend(struct device *dev) 287 { 288 struct of_serial_info *info = dev_get_drvdata(dev); 289 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 290 struct uart_port *port = &port8250->port; 291 292 serial8250_suspend_port(info->line); 293 294 if (!uart_console(port) || console_suspend_enabled) { 295 pm_runtime_put_sync(dev); 296 clk_disable_unprepare(info->clk); 297 } 298 return 0; 299 } 300 301 static int of_serial_resume(struct device *dev) 302 { 303 struct of_serial_info *info = dev_get_drvdata(dev); 304 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 305 struct uart_port *port = &port8250->port; 306 307 if (!uart_console(port) || console_suspend_enabled) { 308 pm_runtime_get_sync(dev); 309 clk_prepare_enable(info->clk); 310 } 311 312 serial8250_resume_port(info->line); 313 314 return 0; 315 } 316 #endif 317 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); 318 319 /* 320 * A few common types, add more as needed. 321 */ 322 static const struct of_device_id of_platform_serial_table[] = { 323 { .compatible = "ns8250", .data = (void *)PORT_8250, }, 324 { .compatible = "ns16450", .data = (void *)PORT_16450, }, 325 { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, 326 { .compatible = "ns16550", .data = (void *)PORT_16550, }, 327 { .compatible = "ns16750", .data = (void *)PORT_16750, }, 328 { .compatible = "ns16850", .data = (void *)PORT_16850, }, 329 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, }, 330 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, }, 331 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, }, 332 { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, }, 333 { .compatible = "altr,16550-FIFO32", 334 .data = (void *)PORT_ALTR_16550_F32, }, 335 { .compatible = "altr,16550-FIFO64", 336 .data = (void *)PORT_ALTR_16550_F64, }, 337 { .compatible = "altr,16550-FIFO128", 338 .data = (void *)PORT_ALTR_16550_F128, }, 339 { .compatible = "mediatek,mtk-btif", 340 .data = (void *)PORT_MTK_BTIF, }, 341 { .compatible = "mrvl,mmp-uart", 342 .data = (void *)PORT_XSCALE, }, 343 { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, }, 344 { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, }, 345 { /* end of list */ }, 346 }; 347 MODULE_DEVICE_TABLE(of, of_platform_serial_table); 348 349 static struct platform_driver of_platform_serial_driver = { 350 .driver = { 351 .name = "of_serial", 352 .of_match_table = of_platform_serial_table, 353 .pm = &of_serial_pm_ops, 354 }, 355 .probe = of_platform_serial_probe, 356 .remove = of_platform_serial_remove, 357 }; 358 359 module_platform_driver(of_platform_serial_driver); 360 361 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 362 MODULE_LICENSE("GPL"); 363 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); 364