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/init.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/serial_core.h>
16 #include <linux/serial_8250.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
22 struct of_serial_info {
23 int type;
24 int line;
25 };
26
27 /*
28 * Fill a struct uart_port for a given device node
29 */
of_platform_serial_setup(struct platform_device * ofdev,int type,struct uart_port * port)30 static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
31 int type, struct uart_port *port)
32 {
33 struct resource resource;
34 struct device_node *np = ofdev->dev.of_node;
35 u32 clk, spd, prop;
36 int ret;
37
38 memset(port, 0, sizeof *port);
39 if (of_property_read_u32(np, "clock-frequency", &clk)) {
40 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
41 return -ENODEV;
42 }
43 /* If current-speed was set, then try not to change it. */
44 if (of_property_read_u32(np, "current-speed", &spd) == 0)
45 port->custom_divisor = clk / (16 * spd);
46
47 ret = of_address_to_resource(np, 0, &resource);
48 if (ret) {
49 dev_warn(&ofdev->dev, "invalid address\n");
50 return ret;
51 }
52
53 spin_lock_init(&port->lock);
54 port->mapbase = resource.start;
55
56 /* Check for shifted address mapping */
57 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
58 port->mapbase += prop;
59
60 /* Check for registers offset within the devices address range */
61 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
62 port->regshift = prop;
63
64 port->irq = irq_of_parse_and_map(np, 0);
65 port->iotype = UPIO_MEM;
66 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
67 switch (prop) {
68 case 1:
69 port->iotype = UPIO_MEM;
70 break;
71 case 4:
72 port->iotype = UPIO_MEM32;
73 break;
74 default:
75 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
76 prop);
77 return -EINVAL;
78 }
79 }
80
81 port->type = type;
82 port->uartclk = clk;
83 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
84 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
85 port->dev = &ofdev->dev;
86
87 return 0;
88 }
89
90 /*
91 * Try to register a serial port
92 */
93 static struct of_device_id of_platform_serial_table[];
of_platform_serial_probe(struct platform_device * ofdev)94 static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
95 {
96 const struct of_device_id *match;
97 struct of_serial_info *info;
98 struct uart_port port;
99 int port_type;
100 int ret;
101
102 match = of_match_device(of_platform_serial_table, &ofdev->dev);
103 if (!match)
104 return -EINVAL;
105
106 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
107 return -EBUSY;
108
109 info = kmalloc(sizeof(*info), GFP_KERNEL);
110 if (info == NULL)
111 return -ENOMEM;
112
113 port_type = (unsigned long)match->data;
114 ret = of_platform_serial_setup(ofdev, port_type, &port);
115 if (ret)
116 goto out;
117
118 switch (port_type) {
119 #ifdef CONFIG_SERIAL_8250
120 case PORT_8250 ... PORT_MAX_8250:
121 ret = serial8250_register_port(&port);
122 break;
123 #endif
124 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
125 case PORT_NWPSERIAL:
126 ret = nwpserial_register_port(&port);
127 break;
128 #endif
129 default:
130 /* need to add code for these */
131 case PORT_UNKNOWN:
132 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
133 ret = -ENODEV;
134 break;
135 }
136 if (ret < 0)
137 goto out;
138
139 info->type = port_type;
140 info->line = ret;
141 dev_set_drvdata(&ofdev->dev, info);
142 return 0;
143 out:
144 kfree(info);
145 irq_dispose_mapping(port.irq);
146 return ret;
147 }
148
149 /*
150 * Release a line
151 */
of_platform_serial_remove(struct platform_device * ofdev)152 static int of_platform_serial_remove(struct platform_device *ofdev)
153 {
154 struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
155 switch (info->type) {
156 #ifdef CONFIG_SERIAL_8250
157 case PORT_8250 ... PORT_MAX_8250:
158 serial8250_unregister_port(info->line);
159 break;
160 #endif
161 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
162 case PORT_NWPSERIAL:
163 nwpserial_unregister_port(info->line);
164 break;
165 #endif
166 default:
167 /* need to add code for these */
168 break;
169 }
170 kfree(info);
171 return 0;
172 }
173
174 /*
175 * A few common types, add more as needed.
176 */
177 static struct of_device_id __devinitdata of_platform_serial_table[] = {
178 { .compatible = "ns8250", .data = (void *)PORT_8250, },
179 { .compatible = "ns16450", .data = (void *)PORT_16450, },
180 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
181 { .compatible = "ns16550", .data = (void *)PORT_16550, },
182 { .compatible = "ns16750", .data = (void *)PORT_16750, },
183 { .compatible = "ns16850", .data = (void *)PORT_16850, },
184 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
185 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
186 { .compatible = "ibm,qpace-nwp-serial",
187 .data = (void *)PORT_NWPSERIAL, },
188 #endif
189 { .type = "serial", .data = (void *)PORT_UNKNOWN, },
190 { /* end of list */ },
191 };
192
193 static struct platform_driver of_platform_serial_driver = {
194 .driver = {
195 .name = "of_serial",
196 .owner = THIS_MODULE,
197 .of_match_table = of_platform_serial_table,
198 },
199 .probe = of_platform_serial_probe,
200 .remove = of_platform_serial_remove,
201 };
202
203 module_platform_driver(of_platform_serial_driver);
204
205 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
206 MODULE_LICENSE("GPL");
207 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
208