tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
22struct of_serial_info {
23 int type;
24 int line;
25};
26
27/*
28 * Fill a struct uart_port for a given device node
29 */
30static 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 const __be32 *clk, *spd;
36 const __be32 *prop;
37 int ret, prop_size;
38
39 memset(port, 0, sizeof *port);
40 spd = of_get_property(np, "current-speed", NULL);
41 clk = of_get_property(np, "clock-frequency", NULL);
42 if (!clk) {
43 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
44 return -ENODEV;
45 }
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 prop = of_get_property(np, "reg-offset", &prop_size);
58 if (prop && (prop_size == sizeof(u32)))
59 port->mapbase += be32_to_cpup(prop);
60
61 /* Check for registers offset within the devices address range */
62 prop = of_get_property(np, "reg-shift", &prop_size);
63 if (prop && (prop_size == sizeof(u32)))
64 port->regshift = be32_to_cpup(prop);
65
66 port->irq = irq_of_parse_and_map(np, 0);
67 port->iotype = UPIO_MEM;
68 port->type = type;
69 port->uartclk = be32_to_cpup(clk);
70 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
71 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
72 port->dev = &ofdev->dev;
73 /* If current-speed was set, then try not to change it. */
74 if (spd)
75 port->custom_divisor = be32_to_cpup(clk) / (16 * (be32_to_cpup(spd)));
76
77 return 0;
78}
79
80/*
81 * Try to register a serial port
82 */
83static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
84{
85 struct of_serial_info *info;
86 struct uart_port port;
87 int port_type;
88 int ret;
89
90 if (!ofdev->dev.of_match)
91 return -EINVAL;
92
93 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
94 return -EBUSY;
95
96 info = kmalloc(sizeof(*info), GFP_KERNEL);
97 if (info == NULL)
98 return -ENOMEM;
99
100 port_type = (unsigned long)ofdev->dev.of_match->data;
101 ret = of_platform_serial_setup(ofdev, port_type, &port);
102 if (ret)
103 goto out;
104
105 switch (port_type) {
106#ifdef CONFIG_SERIAL_8250
107 case PORT_8250 ... PORT_MAX_8250:
108 ret = serial8250_register_port(&port);
109 break;
110#endif
111#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
112 case PORT_NWPSERIAL:
113 ret = nwpserial_register_port(&port);
114 break;
115#endif
116 default:
117 /* need to add code for these */
118 case PORT_UNKNOWN:
119 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
120 ret = -ENODEV;
121 break;
122 }
123 if (ret < 0)
124 goto out;
125
126 info->type = port_type;
127 info->line = ret;
128 dev_set_drvdata(&ofdev->dev, info);
129 return 0;
130out:
131 kfree(info);
132 irq_dispose_mapping(port.irq);
133 return ret;
134}
135
136/*
137 * Release a line
138 */
139static int of_platform_serial_remove(struct platform_device *ofdev)
140{
141 struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
142 switch (info->type) {
143#ifdef CONFIG_SERIAL_8250
144 case PORT_8250 ... PORT_MAX_8250:
145 serial8250_unregister_port(info->line);
146 break;
147#endif
148#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
149 case PORT_NWPSERIAL:
150 nwpserial_unregister_port(info->line);
151 break;
152#endif
153 default:
154 /* need to add code for these */
155 break;
156 }
157 kfree(info);
158 return 0;
159}
160
161/*
162 * A few common types, add more as needed.
163 */
164static struct of_device_id __devinitdata of_platform_serial_table[] = {
165 { .compatible = "ns8250", .data = (void *)PORT_8250, },
166 { .compatible = "ns16450", .data = (void *)PORT_16450, },
167 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
168 { .compatible = "ns16550", .data = (void *)PORT_16550, },
169 { .compatible = "ns16750", .data = (void *)PORT_16750, },
170 { .compatible = "ns16850", .data = (void *)PORT_16850, },
171#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
172 { .compatible = "ibm,qpace-nwp-serial",
173 .data = (void *)PORT_NWPSERIAL, },
174#endif
175 { .type = "serial", .data = (void *)PORT_UNKNOWN, },
176 { /* end of list */ },
177};
178
179static struct platform_driver of_platform_serial_driver = {
180 .driver = {
181 .name = "of_serial",
182 .owner = THIS_MODULE,
183 .of_match_table = of_platform_serial_table,
184 },
185 .probe = of_platform_serial_probe,
186 .remove = of_platform_serial_remove,
187};
188
189static int __init of_platform_serial_init(void)
190{
191 return platform_driver_register(&of_platform_serial_driver);
192}
193module_init(of_platform_serial_init);
194
195static void __exit of_platform_serial_exit(void)
196{
197 return platform_driver_unregister(&of_platform_serial_driver);
198};
199module_exit(of_platform_serial_exit);
200
201MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
202MODULE_LICENSE("GPL");
203MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");