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
20 struct ioc3_8250_data {
21 int line;
22 };
23
ioc3_serial_in(struct uart_port * p,int offset)24 static unsigned int ioc3_serial_in(struct uart_port *p, int offset)
25 {
26 return readb(p->membase + (offset ^ 3));
27 }
28
ioc3_serial_out(struct uart_port * p,int offset,int value)29 static void ioc3_serial_out(struct uart_port *p, int offset, int value)
30 {
31 writeb(value, p->membase + (offset ^ 3));
32 }
33
serial8250_ioc3_probe(struct platform_device * pdev)34 static 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
serial8250_ioc3_remove(struct platform_device * pdev)78 static int 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 return 0;
84 }
85
86 static struct platform_driver serial8250_ioc3_driver = {
87 .probe = serial8250_ioc3_probe,
88 .remove = serial8250_ioc3_remove,
89 .driver = {
90 .name = "ioc3-serial8250",
91 }
92 };
93
94 module_platform_driver(serial8250_ioc3_driver);
95
96 MODULE_AUTHOR("Thomas Bogendoerfer <tbogendoerfer@suse.de>");
97 MODULE_DESCRIPTION("SGI IOC3 8250 UART driver");
98 MODULE_LICENSE("GPL");
99