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/delay.h>
16#include <linux/serial_core.h>
17#include <linux/serial_8250.h>
18#include <linux/serial_reg.h>
19#include <linux/of_address.h>
20#include <linux/of_irq.h>
21#include <linux/of_serial.h>
22#include <linux/of_platform.h>
23#include <linux/nwpserial.h>
24
25struct of_serial_info {
26 int type;
27 int line;
28};
29
30#ifdef CONFIG_ARCH_TEGRA
31void tegra_serial_handle_break(struct uart_port *p)
32{
33 unsigned int status, tmout = 10000;
34
35 do {
36 status = p->serial_in(p, UART_LSR);
37 if (status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS))
38 status = p->serial_in(p, UART_RX);
39 else
40 break;
41 if (--tmout == 0)
42 break;
43 udelay(1);
44 } while (1);
45}
46/* FIXME remove this export when tegra finishes conversion to open firmware */
47EXPORT_SYMBOL_GPL(tegra_serial_handle_break);
48#endif
49
50/*
51 * Fill a struct uart_port for a given device node
52 */
53static int __devinit of_platform_serial_setup(struct platform_device *ofdev,
54 int type, struct uart_port *port)
55{
56 struct resource resource;
57 struct device_node *np = ofdev->dev.of_node;
58 u32 clk, spd, prop;
59 int ret;
60
61 memset(port, 0, sizeof *port);
62 if (of_property_read_u32(np, "clock-frequency", &clk)) {
63 dev_warn(&ofdev->dev, "no clock-frequency property set\n");
64 return -ENODEV;
65 }
66 /* If current-speed was set, then try not to change it. */
67 if (of_property_read_u32(np, "current-speed", &spd) == 0)
68 port->custom_divisor = clk / (16 * spd);
69
70 ret = of_address_to_resource(np, 0, &resource);
71 if (ret) {
72 dev_warn(&ofdev->dev, "invalid address\n");
73 return ret;
74 }
75
76 spin_lock_init(&port->lock);
77 port->mapbase = resource.start;
78
79 /* Check for shifted address mapping */
80 if (of_property_read_u32(np, "reg-offset", &prop) == 0)
81 port->mapbase += prop;
82
83 /* Check for registers offset within the devices address range */
84 if (of_property_read_u32(np, "reg-shift", &prop) == 0)
85 port->regshift = prop;
86
87 port->irq = irq_of_parse_and_map(np, 0);
88 port->iotype = UPIO_MEM;
89 if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
90 switch (prop) {
91 case 1:
92 port->iotype = UPIO_MEM;
93 break;
94 case 4:
95 port->iotype = UPIO_MEM32;
96 break;
97 default:
98 dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
99 prop);
100 return -EINVAL;
101 }
102 }
103
104 port->type = type;
105 port->uartclk = clk;
106 port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
107 | UPF_FIXED_PORT | UPF_FIXED_TYPE;
108
109 if (of_find_property(np, "no-loopback-test", NULL))
110 port->flags |= UPF_SKIP_TEST;
111
112 port->dev = &ofdev->dev;
113
114 if (type == PORT_TEGRA)
115 port->handle_break = tegra_serial_handle_break;
116
117 return 0;
118}
119
120/*
121 * Try to register a serial port
122 */
123static struct of_device_id of_platform_serial_table[];
124static int __devinit of_platform_serial_probe(struct platform_device *ofdev)
125{
126 const struct of_device_id *match;
127 struct of_serial_info *info;
128 struct uart_port port;
129 int port_type;
130 int ret;
131
132 match = of_match_device(of_platform_serial_table, &ofdev->dev);
133 if (!match)
134 return -EINVAL;
135
136 if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
137 return -EBUSY;
138
139 info = kmalloc(sizeof(*info), GFP_KERNEL);
140 if (info == NULL)
141 return -ENOMEM;
142
143 port_type = (unsigned long)match->data;
144 ret = of_platform_serial_setup(ofdev, port_type, &port);
145 if (ret)
146 goto out;
147
148 switch (port_type) {
149#ifdef CONFIG_SERIAL_8250
150 case PORT_8250 ... PORT_MAX_8250:
151 {
152 /* For now the of bindings don't support the extra
153 8250 specific bits */
154 struct uart_8250_port port8250;
155 memset(&port8250, 0, sizeof(port8250));
156 port8250.port = port;
157 ret = serial8250_register_8250_port(&port8250);
158 break;
159 }
160#endif
161#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
162 case PORT_NWPSERIAL:
163 ret = nwpserial_register_port(&port);
164 break;
165#endif
166 default:
167 /* need to add code for these */
168 case PORT_UNKNOWN:
169 dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
170 ret = -ENODEV;
171 break;
172 }
173 if (ret < 0)
174 goto out;
175
176 info->type = port_type;
177 info->line = ret;
178 dev_set_drvdata(&ofdev->dev, info);
179 return 0;
180out:
181 kfree(info);
182 irq_dispose_mapping(port.irq);
183 return ret;
184}
185
186/*
187 * Release a line
188 */
189static int of_platform_serial_remove(struct platform_device *ofdev)
190{
191 struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
192 switch (info->type) {
193#ifdef CONFIG_SERIAL_8250
194 case PORT_8250 ... PORT_MAX_8250:
195 serial8250_unregister_port(info->line);
196 break;
197#endif
198#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
199 case PORT_NWPSERIAL:
200 nwpserial_unregister_port(info->line);
201 break;
202#endif
203 default:
204 /* need to add code for these */
205 break;
206 }
207 kfree(info);
208 return 0;
209}
210
211/*
212 * A few common types, add more as needed.
213 */
214static struct of_device_id __devinitdata of_platform_serial_table[] = {
215 { .compatible = "ns8250", .data = (void *)PORT_8250, },
216 { .compatible = "ns16450", .data = (void *)PORT_16450, },
217 { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
218 { .compatible = "ns16550", .data = (void *)PORT_16550, },
219 { .compatible = "ns16750", .data = (void *)PORT_16750, },
220 { .compatible = "ns16850", .data = (void *)PORT_16850, },
221 { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
222 { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
223#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
224 { .compatible = "ibm,qpace-nwp-serial",
225 .data = (void *)PORT_NWPSERIAL, },
226#endif
227 { .type = "serial", .data = (void *)PORT_UNKNOWN, },
228 { /* end of list */ },
229};
230
231static struct platform_driver of_platform_serial_driver = {
232 .driver = {
233 .name = "of_serial",
234 .owner = THIS_MODULE,
235 .of_match_table = of_platform_serial_table,
236 },
237 .probe = of_platform_serial_probe,
238 .remove = of_platform_serial_remove,
239};
240
241module_platform_driver(of_platform_serial_driver);
242
243MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
244MODULE_LICENSE("GPL");
245MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");