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/module.h>
13 #include <linux/slab.h>
14 #include <linux/delay.h>
15 #include <linux/serial_core.h>
16 #include <linux/serial_reg.h>
17 #include <linux/of_address.h>
18 #include <linux/of_irq.h>
19 #include <linux/of_platform.h>
20 #include <linux/nwpserial.h>
21 #include <linux/clk.h>
22
23 #include "8250/8250.h"
24
25 struct of_serial_info {
26 struct clk *clk;
27 int type;
28 int line;
29 };
30
31 #ifdef CONFIG_ARCH_TEGRA
tegra_serial_handle_break(struct uart_port * p)32 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
tegra_serial_handle_break(struct uart_port * port)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 */
of_platform_serial_setup(struct platform_device * ofdev,int type,struct uart_port * port,struct of_serial_info * info)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 = 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 clk_prepare_enable(info->clk);
77 clk = clk_get_rate(info->clk);
78 }
79 /* If current-speed was set, then try not to change it. */
80 if (of_property_read_u32(np, "current-speed", &spd) == 0)
81 port->custom_divisor = clk / (16 * spd);
82
83 ret = of_address_to_resource(np, 0, &resource);
84 if (ret) {
85 dev_warn(&ofdev->dev, "invalid address\n");
86 goto out;
87 }
88
89 spin_lock_init(&port->lock);
90 port->mapbase = resource.start;
91
92 /* Check for shifted address mapping */
93 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
94 port->mapbase += prop;
95
96 /* Check for registers offset within the devices address range */
97 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
98 port->regshift = prop;
99
100 /* Check for fifo size */
101 if (of_property_read_u32(np, "fifo-size", &prop) == 0)
102 port->fifosize = prop;
103
104 port->irq = irq_of_parse_and_map(np, 0);
105 port->iotype = UPIO_MEM;
106 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
107 switch (prop) {
108 case 1:
109 port->iotype = UPIO_MEM;
110 break;
111 case 4:
112 port->iotype = UPIO_MEM32;
113 break;
114 default:
115 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
116 prop);
117 ret = -EINVAL;
118 goto out;
119 }
120 }
121
122 port->type = type;
123 port->uartclk = clk;
124 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
125 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
126
127 if (of_find_property(np, "no-loopback-test", NULL))
128 port->flags |= UPF_SKIP_TEST;
129
130 port->dev = &ofdev->dev;
131
132 if (type == PORT_TEGRA)
133 port->handle_break = tegra_serial_handle_break;
134
135 return 0;
136 out:
137 if (info->clk)
138 clk_disable_unprepare(info->clk);
139 return ret;
140 }
141
142 /*
143 * Try to register a serial port
144 */
145 static struct of_device_id of_platform_serial_table[];
of_platform_serial_probe(struct platform_device * ofdev)146 static int of_platform_serial_probe(struct platform_device *ofdev)
147 {
148 const struct of_device_id *match;
149 struct of_serial_info *info;
150 struct uart_port port;
151 int port_type;
152 int ret;
153
154 match = of_match_device(of_platform_serial_table, &ofdev->dev);
155 if (!match)
156 return -EINVAL;
157
158 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
159 return -EBUSY;
160
161 info = kzalloc(sizeof(*info), GFP_KERNEL);
162 if (info == NULL)
163 return -ENOMEM;
164
165 port_type = (unsigned long)match->data;
166 ret = of_platform_serial_setup(ofdev, port_type, &port, info);
167 if (ret)
168 goto out;
169
170 switch (port_type) {
171 #ifdef CONFIG_SERIAL_8250
172 case PORT_8250 ... PORT_MAX_8250:
173 {
174 struct uart_8250_port port8250;
175 memset(&port8250, 0, sizeof(port8250));
176 port.type = port_type;
177 port8250.port = port;
178
179 if (port.fifosize)
180 port8250.capabilities = UART_CAP_FIFO;
181
182 if (of_property_read_bool(ofdev->dev.of_node,
183 "auto-flow-control"))
184 port8250.capabilities |= UART_CAP_AFE;
185
186 ret = serial8250_register_8250_port(&port8250);
187 break;
188 }
189 #endif
190 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
191 case PORT_NWPSERIAL:
192 ret = nwpserial_register_port(&port);
193 break;
194 #endif
195 default:
196 /* need to add code for these */
197 case PORT_UNKNOWN:
198 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
199 ret = -ENODEV;
200 break;
201 }
202 if (ret < 0)
203 goto out;
204
205 info->type = port_type;
206 info->line = ret;
207 platform_set_drvdata(ofdev, info);
208 return 0;
209 out:
210 kfree(info);
211 irq_dispose_mapping(port.irq);
212 return ret;
213 }
214
215 /*
216 * Release a line
217 */
of_platform_serial_remove(struct platform_device * ofdev)218 static int of_platform_serial_remove(struct platform_device *ofdev)
219 {
220 struct of_serial_info *info = platform_get_drvdata(ofdev);
221 switch (info->type) {
222 #ifdef CONFIG_SERIAL_8250
223 case PORT_8250 ... PORT_MAX_8250:
224 serial8250_unregister_port(info->line);
225 break;
226 #endif
227 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
228 case PORT_NWPSERIAL:
229 nwpserial_unregister_port(info->line);
230 break;
231 #endif
232 default:
233 /* need to add code for these */
234 break;
235 }
236
237 if (info->clk)
238 clk_disable_unprepare(info->clk);
239 kfree(info);
240 return 0;
241 }
242
243 /*
244 * A few common types, add more as needed.
245 */
246 static struct of_device_id of_platform_serial_table[] = {
247 { .compatible = "ns8250", .data = (void *)PORT_8250, },
248 { .compatible = "ns16450", .data = (void *)PORT_16450, },
249 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
250 { .compatible = "ns16550", .data = (void *)PORT_16550, },
251 { .compatible = "ns16750", .data = (void *)PORT_16750, },
252 { .compatible = "ns16850", .data = (void *)PORT_16850, },
253 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
254 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
255 { .compatible = "altr,16550-FIFO32",
256 .data = (void *)PORT_ALTR_16550_F32, },
257 { .compatible = "altr,16550-FIFO64",
258 .data = (void *)PORT_ALTR_16550_F64, },
259 { .compatible = "altr,16550-FIFO128",
260 .data = (void *)PORT_ALTR_16550_F128, },
261 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
262 { .compatible = "ibm,qpace-nwp-serial",
263 .data = (void *)PORT_NWPSERIAL, },
264 #endif
265 { /* end of list */ },
266 };
267
268 static struct platform_driver of_platform_serial_driver = {
269 .driver = {
270 .name = "of_serial",
271 .owner = THIS_MODULE,
272 .of_match_table = of_platform_serial_table,
273 },
274 .probe = of_platform_serial_probe,
275 .remove = of_platform_serial_remove,
276 };
277
278 module_platform_driver(of_platform_serial_driver);
279
280 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
281 MODULE_LICENSE("GPL");
282 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
283