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/nwpserial.h>
22 #include <linux/clk.h>
23
24 #ifdef CONFIG_SERIAL_8250_MODULE
25 #define CONFIG_SERIAL_8250 CONFIG_SERIAL_8250_MODULE
26 #endif
27
28 #include "8250/8250.h"
29
30 struct of_serial_info {
31 struct clk *clk;
32 int type;
33 int line;
34 };
35
36 #ifdef CONFIG_ARCH_TEGRA
tegra_serial_handle_break(struct uart_port * p)37 void tegra_serial_handle_break(struct uart_port *p)
38 {
39 unsigned int status, tmout = 10000;
40
41 do {
42 status = p->serial_in(p, UART_LSR);
43 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
44 status = p->serial_in(p, UART_RX);
45 else
46 break;
47 if (--tmout == 0)
48 break;
49 udelay(1);
50 } while (1);
51 }
52 #else
tegra_serial_handle_break(struct uart_port * port)53 static inline void tegra_serial_handle_break(struct uart_port *port)
54 {
55 }
56 #endif
57
58 /*
59 * Fill a struct uart_port for a given device node
60 */
of_platform_serial_setup(struct platform_device * ofdev,int type,struct uart_port * port,struct of_serial_info * info)61 static int of_platform_serial_setup(struct platform_device *ofdev,
62 int type, struct uart_port *port,
63 struct of_serial_info *info)
64 {
65 struct resource resource;
66 struct device_node *np = ofdev->dev.of_node;
67 u32 clk, spd, prop;
68 int ret;
69
70 memset(port, 0, sizeof *port);
71 if (of_property_read_u32(np, "clock-frequency", &clk)) {
72
73 /* Get clk rate through clk driver if present */
74 info->clk = devm_clk_get(&ofdev->dev, NULL);
75 if (IS_ERR(info->clk)) {
76 dev_warn(&ofdev->dev,
77 "clk or clock-frequency not defined\n");
78 return PTR_ERR(info->clk);
79 }
80
81 ret = clk_prepare_enable(info->clk);
82 if (ret < 0)
83 return ret;
84
85 clk = clk_get_rate(info->clk);
86 }
87 /* If current-speed was set, then try not to change it. */
88 if (of_property_read_u32(np, "current-speed", &spd) == 0)
89 port->custom_divisor = clk / (16 * spd);
90
91 ret = of_address_to_resource(np, 0, &resource);
92 if (ret) {
93 dev_warn(&ofdev->dev, "invalid address\n");
94 goto out;
95 }
96
97 spin_lock_init(&port->lock);
98 port->mapbase = resource.start;
99 port->mapsize = resource_size(&resource);
100
101 /* Check for shifted address mapping */
102 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
103 port->mapbase += prop;
104
105 /* Check for registers offset within the devices address range */
106 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
107 port->regshift = prop;
108
109 /* Check for fifo size */
110 if (of_property_read_u32(np, "fifo-size", &prop) == 0)
111 port->fifosize = prop;
112
113 /* Check for a fixed line number */
114 ret = of_alias_get_id(np, "serial");
115 if (ret >= 0)
116 port->line = ret;
117
118 port->irq = irq_of_parse_and_map(np, 0);
119 port->iotype = UPIO_MEM;
120 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
121 switch (prop) {
122 case 1:
123 port->iotype = UPIO_MEM;
124 break;
125 case 4:
126 port->iotype = of_device_is_big_endian(np) ?
127 UPIO_MEM32BE : UPIO_MEM32;
128 break;
129 default:
130 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
131 prop);
132 ret = -EINVAL;
133 goto out;
134 }
135 }
136
137 port->type = type;
138 port->uartclk = clk;
139 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
140 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
141
142 if (of_find_property(np, "no-loopback-test", NULL))
143 port->flags |= UPF_SKIP_TEST;
144
145 port->dev = &ofdev->dev;
146
147 switch (type) {
148 case PORT_TEGRA:
149 port->handle_break = tegra_serial_handle_break;
150 break;
151
152 case PORT_RT2880:
153 port->iotype = UPIO_AU;
154 break;
155 }
156
157 if (IS_ENABLED(CONFIG_SERIAL_8250_FSL) &&
158 (of_device_is_compatible(np, "fsl,ns16550") ||
159 of_device_is_compatible(np, "fsl,16550-FIFO64")))
160 port->handle_irq = fsl8250_handle_irq;
161
162 return 0;
163 out:
164 if (info->clk)
165 clk_disable_unprepare(info->clk);
166 return ret;
167 }
168
169 /*
170 * Try to register a serial port
171 */
172 static const struct of_device_id of_platform_serial_table[];
of_platform_serial_probe(struct platform_device * ofdev)173 static int of_platform_serial_probe(struct platform_device *ofdev)
174 {
175 const struct of_device_id *match;
176 struct of_serial_info *info;
177 struct uart_port port;
178 int port_type;
179 int ret;
180
181 match = of_match_device(of_platform_serial_table, &ofdev->dev);
182 if (!match)
183 return -EINVAL;
184
185 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
186 return -EBUSY;
187
188 info = kzalloc(sizeof(*info), GFP_KERNEL);
189 if (info == NULL)
190 return -ENOMEM;
191
192 port_type = (unsigned long)match->data;
193 ret = of_platform_serial_setup(ofdev, port_type, &port, info);
194 if (ret)
195 goto out;
196
197 switch (port_type) {
198 #ifdef CONFIG_SERIAL_8250
199 case PORT_8250 ... PORT_MAX_8250:
200 {
201 struct uart_8250_port port8250;
202 memset(&port8250, 0, sizeof(port8250));
203 port8250.port = port;
204
205 if (port.fifosize)
206 port8250.capabilities = UART_CAP_FIFO;
207
208 if (of_property_read_bool(ofdev->dev.of_node,
209 "auto-flow-control"))
210 port8250.capabilities |= UART_CAP_AFE;
211
212 ret = serial8250_register_8250_port(&port8250);
213 break;
214 }
215 #endif
216 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
217 case PORT_NWPSERIAL:
218 ret = nwpserial_register_port(&port);
219 break;
220 #endif
221 default:
222 /* need to add code for these */
223 case PORT_UNKNOWN:
224 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
225 ret = -ENODEV;
226 break;
227 }
228 if (ret < 0)
229 goto out;
230
231 info->type = port_type;
232 info->line = ret;
233 platform_set_drvdata(ofdev, info);
234 return 0;
235 out:
236 kfree(info);
237 irq_dispose_mapping(port.irq);
238 return ret;
239 }
240
241 /*
242 * Release a line
243 */
of_platform_serial_remove(struct platform_device * ofdev)244 static int of_platform_serial_remove(struct platform_device *ofdev)
245 {
246 struct of_serial_info *info = platform_get_drvdata(ofdev);
247 switch (info->type) {
248 #ifdef CONFIG_SERIAL_8250
249 case PORT_8250 ... PORT_MAX_8250:
250 serial8250_unregister_port(info->line);
251 break;
252 #endif
253 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
254 case PORT_NWPSERIAL:
255 nwpserial_unregister_port(info->line);
256 break;
257 #endif
258 default:
259 /* need to add code for these */
260 break;
261 }
262
263 if (info->clk)
264 clk_disable_unprepare(info->clk);
265 kfree(info);
266 return 0;
267 }
268
269 #ifdef CONFIG_PM_SLEEP
270 #ifdef CONFIG_SERIAL_8250
of_serial_suspend_8250(struct of_serial_info * info)271 static void of_serial_suspend_8250(struct of_serial_info *info)
272 {
273 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
274 struct uart_port *port = &port8250->port;
275
276 serial8250_suspend_port(info->line);
277 if (info->clk && (!uart_console(port) || console_suspend_enabled))
278 clk_disable_unprepare(info->clk);
279 }
280
of_serial_resume_8250(struct of_serial_info * info)281 static void of_serial_resume_8250(struct of_serial_info *info)
282 {
283 struct uart_8250_port *port8250 = serial8250_get_port(info->line);
284 struct uart_port *port = &port8250->port;
285
286 if (info->clk && (!uart_console(port) || console_suspend_enabled))
287 clk_prepare_enable(info->clk);
288
289 serial8250_resume_port(info->line);
290 }
291 #else
of_serial_suspend_8250(struct of_serial_info * info)292 static inline void of_serial_suspend_8250(struct of_serial_info *info)
293 {
294 }
295
of_serial_resume_8250(struct of_serial_info * info)296 static inline void of_serial_resume_8250(struct of_serial_info *info)
297 {
298 }
299 #endif
300
of_serial_suspend(struct device * dev)301 static int of_serial_suspend(struct device *dev)
302 {
303 struct of_serial_info *info = dev_get_drvdata(dev);
304
305 switch (info->type) {
306 case PORT_8250 ... PORT_MAX_8250:
307 of_serial_suspend_8250(info);
308 break;
309 default:
310 break;
311 }
312
313 return 0;
314 }
315
of_serial_resume(struct device * dev)316 static int of_serial_resume(struct device *dev)
317 {
318 struct of_serial_info *info = dev_get_drvdata(dev);
319
320 switch (info->type) {
321 case PORT_8250 ... PORT_MAX_8250:
322 of_serial_resume_8250(info);
323 break;
324 default:
325 break;
326 }
327
328 return 0;
329 }
330 #endif
331 static SIMPLE_DEV_PM_OPS(of_serial_pm_ops, of_serial_suspend, of_serial_resume);
332
333 /*
334 * A few common types, add more as needed.
335 */
336 static const struct of_device_id of_platform_serial_table[] = {
337 { .compatible = "ns8250", .data = (void *)PORT_8250, },
338 { .compatible = "ns16450", .data = (void *)PORT_16450, },
339 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
340 { .compatible = "ns16550", .data = (void *)PORT_16550, },
341 { .compatible = "ns16750", .data = (void *)PORT_16750, },
342 { .compatible = "ns16850", .data = (void *)PORT_16850, },
343 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
344 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
345 { .compatible = "ralink,rt2880-uart", .data = (void *)PORT_RT2880, },
346 { .compatible = "altr,16550-FIFO32",
347 .data = (void *)PORT_ALTR_16550_F32, },
348 { .compatible = "altr,16550-FIFO64",
349 .data = (void *)PORT_ALTR_16550_F64, },
350 { .compatible = "altr,16550-FIFO128",
351 .data = (void *)PORT_ALTR_16550_F128, },
352 { .compatible = "mrvl,mmp-uart",
353 .data = (void *)PORT_XSCALE, },
354 { .compatible = "mrvl,pxa-uart",
355 .data = (void *)PORT_XSCALE, },
356 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
357 { .compatible = "ibm,qpace-nwp-serial",
358 .data = (void *)PORT_NWPSERIAL, },
359 #endif
360 { /* end of list */ },
361 };
362 MODULE_DEVICE_TABLE(of, of_platform_serial_table);
363
364 static struct platform_driver of_platform_serial_driver = {
365 .driver = {
366 .name = "of_serial",
367 .of_match_table = of_platform_serial_table,
368 },
369 .probe = of_platform_serial_probe,
370 .remove = of_platform_serial_remove,
371 };
372
373 module_platform_driver(of_platform_serial_driver);
374
375 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
376 MODULE_LICENSE("GPL");
377 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
378