Root/drivers/tty/serial/of_serial.c

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_platform.h>
22#include <linux/nwpserial.h>
23#include <linux/clk.h>
24
25struct of_serial_info {
26    struct clk *clk;
27    int type;
28    int line;
29};
30
31#ifdef CONFIG_ARCH_TEGRA
32void 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
48static 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 */
56static 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    port->irq = irq_of_parse_and_map(np, 0);
101    port->iotype = UPIO_MEM;
102    if (of_property_read_u32(np, "reg-io-width", &prop) == 0) {
103        switch (prop) {
104        case 1:
105            port->iotype = UPIO_MEM;
106            break;
107        case 4:
108            port->iotype = UPIO_MEM32;
109            break;
110        default:
111            dev_warn(&ofdev->dev, "unsupported reg-io-width (%d)\n",
112                 prop);
113            ret = -EINVAL;
114            goto out;
115        }
116    }
117
118    port->type = type;
119    port->uartclk = clk;
120    port->flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF | UPF_IOREMAP
121        | UPF_FIXED_PORT | UPF_FIXED_TYPE;
122
123    if (of_find_property(np, "no-loopback-test", NULL))
124        port->flags |= UPF_SKIP_TEST;
125
126    port->dev = &ofdev->dev;
127
128    if (type == PORT_TEGRA)
129        port->handle_break = tegra_serial_handle_break;
130
131    return 0;
132out:
133    if (info->clk)
134        clk_disable_unprepare(info->clk);
135    return ret;
136}
137
138/*
139 * Try to register a serial port
140 */
141static struct of_device_id of_platform_serial_table[];
142static int of_platform_serial_probe(struct platform_device *ofdev)
143{
144    const struct of_device_id *match;
145    struct of_serial_info *info;
146    struct uart_port port;
147    int port_type;
148    int ret;
149
150    match = of_match_device(of_platform_serial_table, &ofdev->dev);
151    if (!match)
152        return -EINVAL;
153
154    if (of_find_property(ofdev->dev.of_node, "used-by-rtas", NULL))
155        return -EBUSY;
156
157    info = kmalloc(sizeof(*info), GFP_KERNEL);
158    if (info == NULL)
159        return -ENOMEM;
160
161    port_type = (unsigned long)match->data;
162    ret = of_platform_serial_setup(ofdev, port_type, &port, info);
163    if (ret)
164        goto out;
165
166    switch (port_type) {
167#ifdef CONFIG_SERIAL_8250
168    case PORT_8250 ... PORT_MAX_8250:
169    {
170        /* For now the of bindings don't support the extra
171           8250 specific bits */
172        struct uart_8250_port port8250;
173        memset(&port8250, 0, sizeof(port8250));
174        port8250.port = port;
175        ret = serial8250_register_8250_port(&port8250);
176        break;
177    }
178#endif
179#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
180    case PORT_NWPSERIAL:
181        ret = nwpserial_register_port(&port);
182        break;
183#endif
184    default:
185        /* need to add code for these */
186    case PORT_UNKNOWN:
187        dev_info(&ofdev->dev, "Unknown serial port found, ignored\n");
188        ret = -ENODEV;
189        break;
190    }
191    if (ret < 0)
192        goto out;
193
194    info->type = port_type;
195    info->line = ret;
196    dev_set_drvdata(&ofdev->dev, info);
197    return 0;
198out:
199    kfree(info);
200    irq_dispose_mapping(port.irq);
201    return ret;
202}
203
204/*
205 * Release a line
206 */
207static int of_platform_serial_remove(struct platform_device *ofdev)
208{
209    struct of_serial_info *info = dev_get_drvdata(&ofdev->dev);
210    switch (info->type) {
211#ifdef CONFIG_SERIAL_8250
212    case PORT_8250 ... PORT_MAX_8250:
213        serial8250_unregister_port(info->line);
214        break;
215#endif
216#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
217    case PORT_NWPSERIAL:
218        nwpserial_unregister_port(info->line);
219        break;
220#endif
221    default:
222        /* need to add code for these */
223        break;
224    }
225
226    if (info->clk)
227        clk_disable_unprepare(info->clk);
228    kfree(info);
229    return 0;
230}
231
232/*
233 * A few common types, add more as needed.
234 */
235static struct of_device_id of_platform_serial_table[] = {
236    { .compatible = "ns8250", .data = (void *)PORT_8250, },
237    { .compatible = "ns16450", .data = (void *)PORT_16450, },
238    { .compatible = "ns16550a", .data = (void *)PORT_16550A, },
239    { .compatible = "ns16550", .data = (void *)PORT_16550, },
240    { .compatible = "ns16750", .data = (void *)PORT_16750, },
241    { .compatible = "ns16850", .data = (void *)PORT_16850, },
242    { .compatible = "nvidia,tegra20-uart", .data = (void *)PORT_TEGRA, },
243    { .compatible = "nxp,lpc3220-uart", .data = (void *)PORT_LPC3220, },
244    { .compatible = "altr,16550-FIFO32",
245        .data = (void *)PORT_ALTR_16550_F32, },
246    { .compatible = "altr,16550-FIFO64",
247        .data = (void *)PORT_ALTR_16550_F64, },
248    { .compatible = "altr,16550-FIFO128",
249        .data = (void *)PORT_ALTR_16550_F128, },
250#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL
251    { .compatible = "ibm,qpace-nwp-serial",
252        .data = (void *)PORT_NWPSERIAL, },
253#endif
254    { .type = "serial", .data = (void *)PORT_UNKNOWN, },
255    { /* end of list */ },
256};
257
258static struct platform_driver of_platform_serial_driver = {
259    .driver = {
260        .name = "of_serial",
261        .owner = THIS_MODULE,
262        .of_match_table = of_platform_serial_table,
263    },
264    .probe = of_platform_serial_probe,
265    .remove = of_platform_serial_remove,
266};
267
268module_platform_driver(of_platform_serial_driver);
269
270MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
271MODULE_LICENSE("GPL");
272MODULE_DESCRIPTION("Serial Port driver for Open Firmware platform devices");
273

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