1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SGI IOC3 8250 UART driver
4 *
5 * Copyright (C) 2019 Thomas Bogendoerfer <tbogendoerfer@suse.de>
6 *
7 * based on code Copyright (C) 2005 Stanislaw Skowronek <skylark@unaligned.org>
8 *               Copyright (C) 2014 Joshua Kinard <kumba@gentoo.org>
9 */
10
11#include <linux/module.h>
12#include <linux/errno.h>
13#include <linux/io.h>
14#include <linux/platform_device.h>
15
16#include "8250.h"
17
18#define IOC3_UARTCLK (22000000 / 3)
19
20struct ioc3_8250_data {
21	int line;
22};
23
24static unsigned int ioc3_serial_in(struct uart_port *p, int offset)
25{
26	return readb(p->membase + (offset ^ 3));
27}
28
29static void ioc3_serial_out(struct uart_port *p, int offset, int value)
30{
31	writeb(value, p->membase + (offset ^ 3));
32}
33
34static int serial8250_ioc3_probe(struct platform_device *pdev)
35{
36	struct ioc3_8250_data *data;
37	struct uart_8250_port up;
38	struct resource *r;
39	void __iomem *membase;
40	int irq, line;
41
42	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
43	if (!r)
44		return -ENODEV;
45
46	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
47	if (!data)
48		return -ENOMEM;
49
50	membase = devm_ioremap(&pdev->dev, r->start, resource_size(r));
51	if (!membase)
52		return -ENOMEM;
53
54	irq = platform_get_irq(pdev, 0);
55	if (irq < 0)
56		irq = 0; /* no interrupt -> use polling */
57
58	/* Register serial ports with 8250.c */
59	memset(&up, 0, sizeof(struct uart_8250_port));
60	up.port.iotype = UPIO_MEM;
61	up.port.uartclk = IOC3_UARTCLK;
62	up.port.type = PORT_16550A;
63	up.port.irq = irq;
64	up.port.flags = (UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ);
65	up.port.dev = &pdev->dev;
66	up.port.membase = membase;
67	up.port.mapbase = r->start;
68	up.port.serial_in = ioc3_serial_in;
69	up.port.serial_out = ioc3_serial_out;
70	line = serial8250_register_8250_port(&up);
71	if (line < 0)
72		return line;
73
74	platform_set_drvdata(pdev, data);
75	return 0;
76}
77
78static void serial8250_ioc3_remove(struct platform_device *pdev)
79{
80	struct ioc3_8250_data *data = platform_get_drvdata(pdev);
81
82	serial8250_unregister_port(data->line);
83}
84
85static struct platform_driver serial8250_ioc3_driver = {
86	.probe  = serial8250_ioc3_probe,
87	.remove_new = serial8250_ioc3_remove,
88	.driver = {
89		.name = "ioc3-serial8250",
90	}
91};
92
93module_platform_driver(serial8250_ioc3_driver);
94
95MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
96MODULE_DESCRIPTION("SGI IOC3 8250 UART driver");
97MODULE_LICENSE("GPL");
98