1 /* 2 * Serial Port driver for Open Firmware platform devices 3 * 4 * Copyright (C) 2006 Arnd Bergmann <arnd@arndb.de>, IBM Corp. 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 */ 12 #include <linux/console.h> 13 #include <linux/module.h> 14 #include <linux/slab.h> 15 #include <linux/delay.h> 16 #include <linux/serial_core.h> 17 #include <linux/serial_reg.h> 18 #include <linux/of_address.h> 19 #include <linux/of_irq.h> 20 #include <linux/of_platform.h> 21 #include <linux/clk.h> 22 23 #include "8250.h" 24 25 struct of_serial_info { 26 struct clk *clk; 27 int type; 28 int line; 29 }; 30 31 #ifdef CONFIG_ARCH_TEGRA 32 static void tegra_serial_handle_break(struct uart_port *p) 33 { 34 unsigned int status, tmout = 10000; 35 36 do { 37 status = p->serial_in(p, UART_LSR); 38 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) 39 status = p->serial_in(p, UART_RX); 40 else 41 break; 42 if (--tmout == 0) 43 break; 44 udelay(1); 45 } while (1); 46 } 47 #else 48 static inline void tegra_serial_handle_break(struct uart_port *port) 49 { 50 } 51 #endif 52 53 /* 54 * Fill a struct uart_port for a given device node 55 */ 56 static int of_platform_serial_setup(struct platform_device *ofdev, 57 int type, struct uart_port *port, 58 struct of_serial_info *info) 59 { 60 struct resource resource; 61 struct device_node *np = ofdev->dev.of_node; 62 u32 clk, spd, prop; 63 int ret; 64 65 memset(port, 0, sizeof *port); 66 if (of_property_read_u32(np, "clock-frequency", &clk)) { 67 68 /* Get clk rate through clk driver if present */ 69 info->clk = devm_clk_get(&ofdev->dev, NULL); 70 if (IS_ERR(info->clk)) { 71 dev_warn(&ofdev->dev, 72 "clk or clock-frequency not defined\n"); 73 return PTR_ERR(info->clk); 74 } 75 76 ret = clk_prepare_enable(info->clk); 77 if (ret < 0) 78 return ret; 79 80 clk = clk_get_rate(info->clk); 81 } 82 /* If current-speed was set, then try not to change it. */ 83 if (of_property_read_u32(np, "current-speed", &spd) == 0) 84 port->custom_divisor = clk / (16 * spd); 85 86 ret = of_address_to_resource(np, 0, &resource); 87 if (ret) { 88 dev_warn(&ofdev->dev, "invalid address\n"); 89 goto out; 90 } 91 92 spin_lock_init(&port->lock); 93 port->mapbase = resource.start; 94 port->mapsize = resource_size(&resource); 95 96 /* Check for shifted address mapping */ 97 if (of_property_read_u32(np, "reg-offset", &prop) == 0) 98 port->mapbase += prop; 99 100 /* Check for registers offset within the devices address range */ 101 if (of_property_read_u32(np, "reg-shift", &prop) == 0) 102 port->regshift = prop; 103 104 /* Check for fifo size */ 105 if (of_property_read_u32(np, "fifo-size", &prop) == 0) 106 port->fifosize = prop; 107 108 /* Check for a fixed line number */ 109 ret = of_alias_get_id(np, "serial"); 110 if (ret >= 0) 111 port->line = ret; 112 113 port->irq = irq_of_parse_and_map(np, 0); 114 port->iotype = UPIO_MEM; 115 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) { 116 switch (prop) { 117 case 1: 118 port->iotype = UPIO_MEM; 119 break; 120 case 2: 121 port->iotype = UPIO_MEM16; 122 break; 123 case 4: 124 port->iotype = of_device_is_big_endian(np) ? 125 UPIO_MEM32BE : UPIO_MEM32; 126 break; 127 default: 128 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n", 129 prop); 130 ret = -EINVAL; 131 goto out; 132 } 133 } 134 135 port->type = type; 136 port->uartclk = clk; 137 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP 138 | UPF_FIXED_PORT | UPF_FIXED_TYPE; 139 140 if (of_find_property(np, "no-loopback-test", NULL)) 141 port->flags |= UPF_SKIP_TEST; 142 143 port->dev = &ofdev->dev; 144 145 switch (type) { 146 case PORT_TEGRA: 147 port->handle_break = tegra_serial_handle_break; 148 break; 149 150 case PORT_RT2880: 151 port->iotype = UPIO_AU; 152 break; 153 } 154 155 if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) && 156 (of_device_is_compatible(np, "fsl,ns16550") || 157 of_device_is_compatible(np, "fsl,16550-FIFO64"))) 158 port->handle_irq = fsl8250_handle_irq; 159 160 return 0; 161 out: 162 if (info->clk) 163 clk_disable_unprepare(info->clk); 164 return ret; 165 } 166 167 /* 168 * Try to register a serial port 169 */ 170 static const struct of_device_id of_platform_serial_table[]; 171 static int of_platform_serial_probe(struct platform_device *ofdev) 172 { 173 const struct of_device_id *match; 174 struct of_serial_info *info; 175 struct uart_port port; 176 int port_type; 177 int ret; 178 179 match = of_match_device(of_platform_serial_table, &ofdev->dev); 180 if (!match) 181 return -EINVAL; 182 183 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL)) 184 return -EBUSY; 185 186 info = kzalloc(sizeof(*info), GFP_KERNEL); 187 if (info == NULL) 188 return -ENOMEM; 189 190 port_type = (unsigned long)match->data; 191 ret = of_platform_serial_setup(ofdev, port_type, &port, info); 192 if (ret) 193 goto out; 194 195 switch (port_type) { 196 case PORT_8250 ... PORT_MAX_8250: 197 { 198 struct uart_8250_port port8250; 199 memset(&port8250, 0, sizeof(port8250)); 200 port8250.port = port; 201 202 if (port.fifosize) 203 port8250.capabilities = UART_CAP_FIFO; 204 205 if (of_property_read_bool(ofdev->dev.of_node, 206 "auto-flow-control")) 207 port8250.capabilities |= UART_CAP_AFE; 208 209 ret = serial8250_register_8250_port(&port8250); 210 break; 211 } 212 default: 213 /* need to add code for these */ 214 case PORT_UNKNOWN: 215 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n"); 216 ret = -ENODEV; 217 break; 218 } 219 if (ret < 0) 220 goto out; 221 222 info->type = port_type; 223 info->line = ret; 224 platform_set_drvdata(ofdev, info); 225 return 0; 226 out: 227 kfree(info); 228 irq_dispose_mapping(port.irq); 229 return ret; 230 } 231 232 /* 233 * Release a line 234 */ 235 static int of_platform_serial_remove(struct platform_device *ofdev) 236 { 237 struct of_serial_info *info = platform_get_drvdata(ofdev); 238 switch (info->type) { 239 case PORT_8250 ... PORT_MAX_8250: 240 serial8250_unregister_port(info->line); 241 break; 242 default: 243 /* need to add code for these */ 244 break; 245 } 246 247 if (info->clk) 248 clk_disable_unprepare(info->clk); 249 kfree(info); 250 return 0; 251 } 252 253 #ifdef CONFIG_PM_SLEEP 254 static void of_serial_suspend_8250(struct of_serial_info *info) 255 { 256 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 257 struct uart_port *port = &port8250->port; 258 259 serial8250_suspend_port(info->line); 260 if (info->clk && (!uart_console(port) || console_suspend_enabled)) 261 clk_disable_unprepare(info->clk); 262 } 263 264 static void of_serial_resume_8250(struct of_serial_info *info) 265 { 266 struct uart_8250_port *port8250 = serial8250_get_port(info->line); 267 struct uart_port *port = &port8250->port; 268 269 if (info->clk && (!uart_console(port) || console_suspend_enabled)) 270 clk_prepare_enable(info->clk); 271 272 serial8250_resume_port(info->line); 273 } 274 275 static int of_serial_suspend(struct device *dev) 276 { 277 struct of_serial_info *info = dev_get_drvdata(dev); 278 279 switch (info->type) { 280 case PORT_8250 ... PORT_MAX_8250: 281 of_serial_suspend_8250(info); 282 break; 283 default: 284 break; 285 } 286 287 return 0; 288 } 289 290 static int of_serial_resume(struct device *dev) 291 { 292 struct of_serial_info *info = dev_get_drvdata(dev); 293 294 switch (info->type) { 295 case PORT_8250 ... PORT_MAX_8250: 296 of_serial_resume_8250(info); 297 break; 298 default: 299 break; 300 } 301 302 return 0; 303 } 304 #endif 305 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume); 306 307 /* 308 * A few common types, add more as needed. 309 */ 310 static const struct of_device_id of_platform_serial_table[] = { 311 { .compatible = "ns8250", .data = (void *)PORT_8250, }, 312 { .compatible = "ns16450", .data = (void *)PORT_16450, }, 313 { .compatible = "ns16550a", .data = (void *)PORT_16550A, }, 314 { .compatible = "ns16550", .data = (void *)PORT_16550, }, 315 { .compatible = "ns16750", .data = (void *)PORT_16750, }, 316 { .compatible = "ns16850", .data = (void *)PORT_16850, }, 317 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, }, 318 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, }, 319 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, }, 320 { .compatible = "altr,16550-FIFO32", 321 .data = (void *)PORT_ALTR_16550_F32, }, 322 { .compatible = "altr,16550-FIFO64", 323 .data = (void *)PORT_ALTR_16550_F64, }, 324 { .compatible = "altr,16550-FIFO128", 325 .data = (void *)PORT_ALTR_16550_F128, }, 326 { .compatible = "mrvl,mmp-uart", 327 .data = (void *)PORT_XSCALE, }, 328 { .compatible = "mrvl,pxa-uart", 329 .data = (void *)PORT_XSCALE, }, 330 { /* end of list */ }, 331 }; 332 MODULE_DEVICE_TABLE(of, of_platform_serial_table); 333 334 static struct platform_driver of_platform_serial_driver = { 335 .driver = { 336 .name = "of_serial", 337 .of_match_table = of_platform_serial_table, 338 .pm = &of_serial_pm_ops, 339 }, 340 .probe = of_platform_serial_probe, 341 .remove = of_platform_serial_remove, 342 }; 343 344 module_platform_driver(of_platform_serial_driver); 345 346 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 347 MODULE_LICENSE("GPL"); 348 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices"); 349