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 if (IS_ENABLED(CONFIG_SERIAL_8250_BCM7271) && 205 of_device_is_compatible(ofdev->dev.of_node, "brcm,bcm7271-uart")) 206 return -ENODEV; 207 208 port_type = (unsigned long)of_device_get_match_data(&ofdev->dev); 209 if (port_type == PORT_UNKNOWN) 210 return -EINVAL; 211 212 if (of_property_read_bool(ofdev->dev.of_node, "used-by-rtas")) 213 return -EBUSY; 214 215 info = kzalloc(sizeof(*info), GFP_KERNEL); 216 if (info == NULL) 217 return -ENOMEM; 218 219 memset(&port8250, 0, sizeof(port8250)); 220 ret = of_platform_serial_setup(ofdev, port_type, &port8250, info); 221 if (ret) 222 goto err_free; 223 224 if (port8250.port.fifosize) 225 port8250.capabilities = UART_CAP_FIFO; 226 227 /* Check for TX FIFO threshold & set tx_loadsz */ 228 if ((of_property_read_u32(ofdev->dev.of_node, "tx-threshold", 229 &tx_threshold) == 0) && 230 (tx_threshold < port8250.port.fifosize)) 231 port8250.tx_loadsz = port8250.port.fifosize - tx_threshold; 232 233 if (of_property_read_bool(ofdev->dev.of_node, "auto-flow-control")) 234 port8250.capabilities |= UART_CAP_AFE; 235 236 if (of_property_read_u32(ofdev->dev.of_node, 237 "overrun-throttle-ms", 238 &port8250.overrun_backoff_time_ms) != 0) 239 port8250.overrun_backoff_time_ms = 0; 240 241 ret = serial8250_register_8250_port(&port8250); 242 if (ret < 0) 243 goto err_dispose; 244 245 info->type = port_type; 246 info->line = ret; 247 platform_set_drvdata(ofdev, info); 248 return 0; 249 err_dispose: 250 irq_dispose_mapping(port8250.port.irq); 251 pm_runtime_put_sync(&ofdev->dev); 252 pm_runtime_disable(&ofdev->dev); 253 clk_disable_unprepare(info->clk); 254 err_free: 255 kfree(info); 256 return ret; 257 } 258 259 /* 260 * Release a line 261 */ 262 static int of_platform_serial_remove(struct platform_device *ofdev) 263 { 264 struct of_serial_info *info = platform_get_drvdata(ofdev); 265 266 serial8250_unregister_port(info->line); 267 268 reset_control_assert(info->rst); 269 pm_runtime_put_sync(&ofdev->dev); 270 pm_runtime_disable(&ofdev->dev); 271 clk_disable_unprepare(info->clk); 272 kfree(info); 273 return 0; 274 } 275 276 #ifdef CONFIG_PM_SLEEP 277 static int of_serial_suspend(struct device *dev) 278 { 279 struct of_serial_info *info = dev_get_drvdata(dev); 280 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 281 struct uart_port *port = &port8250->port; 282 283 serial8250_suspend_port(info->line); 284 285 if (!uart_console(port) || console_suspend_enabled) { 286 pm_runtime_put_sync(dev); 287 clk_disable_unprepare(info->clk); 288 } 289 return 0; 290 } 291 292 static int of_serial_resume(struct device *dev) 293 { 294 struct of_serial_info *info = dev_get_drvdata(dev); 295 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 296 struct uart_port *port = &port8250->port; 297 298 if (!uart_console(port) || console_suspend_enabled) { 299 pm_runtime_get_sync(dev); 300 clk_prepare_enable(info->clk); 301 } 302 303 serial8250_resume_port(info->line); 304 305 return 0; 306 } 307 #endif 308 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); 309 310 /* 311 * A few common types, add more as needed. 312 */ 313 static const struct of_device_id of_platform_serial_table[] = { 314 { .compatible = "ns8250", .data = (void *)PORT_8250, }, 315 { .compatible = "ns16450", .data = (void *)PORT_16450, }, 316 { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, 317 { .compatible = "ns16550", .data = (void *)PORT_16550, }, 318 { .compatible = "ns16750", .data = (void *)PORT_16750, }, 319 { .compatible = "ns16850", .data = (void *)PORT_16850, }, 320 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, }, 321 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, }, 322 { .compatible = "intel,xscale-uart", .data = (void *)PORT_XSCALE, }, 323 { .compatible = "altr,16550-FIFO32", 324 .data = (void *)PORT_ALTR_16550_F32, }, 325 { .compatible = "altr,16550-FIFO64", 326 .data = (void *)PORT_ALTR_16550_F64, }, 327 { .compatible = "altr,16550-FIFO128", 328 .data = (void *)PORT_ALTR_16550_F128, }, 329 { .compatible = "mediatek,mtk-btif", 330 .data = (void *)PORT_MTK_BTIF, }, 331 { .compatible = "mrvl,mmp-uart", 332 .data = (void *)PORT_XSCALE, }, 333 { .compatible = "ti,da830-uart", .data = (void *)PORT_DA830, }, 334 { .compatible = "nuvoton,wpcm450-uart", .data = (void *)PORT_NPCM, }, 335 { .compatible = "nuvoton,npcm750-uart", .data = (void *)PORT_NPCM, }, 336 { /* end of list */ }, 337 }; 338 MODULE_DEVICE_TABLE(of, of_platform_serial_table); 339 340 static struct platform_driver of_platform_serial_driver = { 341 .driver = { 342 .name = "of_serial", 343 .of_match_table = of_platform_serial_table, 344 .pm = &of_serial_pm_ops, 345 }, 346 .probe = of_platform_serial_probe, 347 .remove = of_platform_serial_remove, 348 }; 349 350 module_platform_driver(of_platform_serial_driver); 351 352 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 353 MODULE_LICENSE("GPL"); 354 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); 355