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/serial_core.h>
15 #include <linux/serial_8250.h>
16 #include <linux/of_platform.h>
17 #include <linux/nwpserial.h>
18
19 #include <asm/prom.h>
20
21 struct of_serial_info {
22 int type;
23 int line;
24 };
25
26 /*
27 * Fill a struct uart_port for a given device node
28 */
of_platform_serial_setup(struct of_device * ofdev,int type,struct uart_port * port)29 static int __devinit of_platform_serial_setup(struct of_device *ofdev,
30 int type, struct uart_port *port)
31 {
32 struct resource resource;
33 struct device_node *np = ofdev->node;
34 const unsigned int *clk, *spd;
35 const u32 *prop;
36 int ret, prop_size;
37
38 memset(port, 0, sizeof *port);
39 spd = of_get_property(np, "current-speed", NULL);
40 clk = of_get_property(np, "clock-frequency", NULL);
41 if (!clk) {
42 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
43 return -ENODEV;
44 }
45
46 ret = of_address_to_resource(np, 0, &resource);
47 if (ret) {
48 dev_warn(&ofdev->dev, "invalid address\n");
49 return ret;
50 }
51
52 spin_lock_init(&port->lock);
53 port->mapbase = resource.start;
54
55 /* Check for shifted address mapping */
56 prop = of_get_property(np, "reg-offset", &prop_size);
57 if (prop && (prop_size == sizeof(u32)))
58 port->mapbase += *prop;
59
60 /* Check for registers offset within the devices address range */
61 prop = of_get_property(np, "reg-shift", &prop_size);
62 if (prop && (prop_size == sizeof(u32)))
63 port->regshift = *prop;
64
65 port->irq = irq_of_parse_and_map(np, 0);
66 port->iotype = UPIO_MEM;
67 port->type = type;
68 port->uartclk = *clk;
69 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
70 | UPF_FIXED_PORT;
71 port->dev = &ofdev->dev;
72 /* If current-speed was set, then try not to change it. */
73 if (spd)
74 port->custom_divisor = *clk / (16 * (*spd));
75
76 return 0;
77 }
78
79 /*
80 * Try to register a serial port
81 */
of_platform_serial_probe(struct of_device * ofdev,const struct of_device_id * id)82 static int __devinit of_platform_serial_probe(struct of_device *ofdev,
83 const struct of_device_id *id)
84 {
85 struct of_serial_info *info;
86 struct uart_port port;
87 int port_type;
88 int ret;
89
90 if (of_find_property(ofdev->node, "used-by-rtas", NULL))
91 return -EBUSY;
92
93 info = kmalloc(sizeof(*info), GFP_KERNEL);
94 if (info == NULL)
95 return -ENOMEM;
96
97 port_type = (unsigned long)id->data;
98 ret = of_platform_serial_setup(ofdev, port_type, &port);
99 if (ret)
100 goto out;
101
102 switch (port_type) {
103 #ifdef CONFIG_SERIAL_8250
104 case PORT_8250 ... PORT_MAX_8250:
105 ret = serial8250_register_port(&port);
106 break;
107 #endif
108 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
109 case PORT_NWPSERIAL:
110 ret = nwpserial_register_port(&port);
111 break;
112 #endif
113 default:
114 /* need to add code for these */
115 case PORT_UNKNOWN:
116 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
117 ret = -ENODEV;
118 break;
119 }
120 if (ret < 0)
121 goto out;
122
123 info->type = port_type;
124 info->line = ret;
125 ofdev->dev.driver_data = info;
126 return 0;
127 out:
128 kfree(info);
129 irq_dispose_mapping(port.irq);
130 return ret;
131 }
132
133 /*
134 * Release a line
135 */
of_platform_serial_remove(struct of_device * ofdev)136 static int of_platform_serial_remove(struct of_device *ofdev)
137 {
138 struct of_serial_info *info = ofdev->dev.driver_data;
139 switch (info->type) {
140 #ifdef CONFIG_SERIAL_8250
141 case PORT_8250 ... PORT_MAX_8250:
142 serial8250_unregister_port(info->line);
143 break;
144 #endif
145 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
146 case PORT_NWPSERIAL:
147 nwpserial_unregister_port(info->line);
148 break;
149 #endif
150 default:
151 /* need to add code for these */
152 break;
153 }
154 kfree(info);
155 return 0;
156 }
157
158 /*
159 * A few common types, add more as needed.
160 */
161 static struct of_device_id __devinitdata of_platform_serial_table[] = {
162 { .type = "serial", .compatible = "ns8250", .data = (void *)PORT_8250, },
163 { .type = "serial", .compatible = "ns16450", .data = (void *)PORT_16450, },
164 { .type = "serial", .compatible = "ns16550", .data = (void *)PORT_16550, },
165 { .type = "serial", .compatible = "ns16750", .data = (void *)PORT_16750, },
166 { .type = "serial", .compatible = "ns16850", .data = (void *)PORT_16850, },
167 #ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
168 { .type = "serial", .compatible = "ibm,qpace-nwp-serial",
169 .data = (void *)PORT_NWPSERIAL, },
170 #endif
171 { .type = "serial", .data = (void *)PORT_UNKNOWN, },
172 { /* end of list */ },
173 };
174
175 static struct of_platform_driver of_platform_serial_driver = {
176 .owner = THIS_MODULE,
177 .name = "of_serial",
178 .probe = of_platform_serial_probe,
179 .remove = of_platform_serial_remove,
180 .match_table = of_platform_serial_table,
181 };
182
of_platform_serial_init(void)183 static int __init of_platform_serial_init(void)
184 {
185 return of_register_platform_driver(&of_platform_serial_driver);
186 }
187 module_init(of_platform_serial_init);
188
of_platform_serial_exit(void)189 static void __exit of_platform_serial_exit(void)
190 {
191 return of_unregister_platform_driver(&of_platform_serial_driver);
192 };
193 module_exit(of_platform_serial_exit);
194
195 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
196 MODULE_LICENSE("GPL");
197 MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
198