1// SPDX-License-Identifier: GPL-2.0
2#include <linux/device.h>
3#include <linux/kernel.h>
4#include <linux/module.h>
5#include <linux/io.h>
6#include <linux/mcb.h>
7#include <linux/serial.h>
8#include <linux/serial_core.h>
9#include <linux/serial_8250.h>
10#include <uapi/linux/serial_core.h>
11
12#define MEN_UART_ID_Z025 0x19
13#define MEN_UART_ID_Z057 0x39
14#define MEN_UART_ID_Z125 0x7d
15
16#define MEN_UART_MEM_SIZE 0x10
17
18struct serial_8250_men_mcb_data {
19	struct uart_8250_port uart;
20	int line;
21};
22
23/*
24 * The Z125 16550-compatible UART has no fixed base clock assigned
25 * So, depending on the board we're on, we need to adjust the
26 * parameter in order to really set the correct baudrate, and
27 * do so if possible without user interaction
28 */
29static u32 men_lookup_uartclk(struct mcb_device *mdev)
30{
31	/* use default value if board is not available below */
32	u32 clkval = 1041666;
33
34	dev_info(&mdev->dev, "%s on board %s\n",
35		dev_name(&mdev->dev),
36		mdev->bus->name);
37	if  (strncmp(mdev->bus->name, "F075", 4) == 0)
38		clkval = 1041666;
39	else if (strncmp(mdev->bus->name, "F216", 4) == 0)
40		clkval = 1843200;
41	else if (strncmp(mdev->bus->name, "G215", 4) == 0)
42		clkval = 1843200;
43	else if (strncmp(mdev->bus->name, "F210", 4) == 0)
44		clkval = 115200;
45	else
46		dev_info(&mdev->dev,
47			 "board not detected, using default uartclk\n");
48
49	clkval = clkval  << 4;
50
51	return clkval;
52}
53
54static int get_num_ports(struct mcb_device *mdev,
55				  void __iomem *membase)
56{
57	switch (mdev->id) {
58	case MEN_UART_ID_Z125:
59		return 1U;
60	case MEN_UART_ID_Z025:
61		return readb(membase) >> 4;
62	case MEN_UART_ID_Z057:
63		return 4U;
64	default:
65		dev_err(&mdev->dev, "no supported device!\n");
66		return -ENODEV;
67	}
68}
69
70static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
71				     const struct mcb_device_id *id)
72{
73	struct serial_8250_men_mcb_data *data;
74	struct resource *mem;
75	int num_ports;
76	int i;
77	void __iomem *membase;
78
79	mem = mcb_get_resource(mdev, IORESOURCE_MEM);
80	if (mem == NULL)
81		return -ENXIO;
82	membase = devm_ioremap_resource(&mdev->dev, mem);
83	if (IS_ERR(membase))
84		return PTR_ERR_OR_ZERO(membase);
85
86	num_ports = get_num_ports(mdev, membase);
87
88	dev_dbg(&mdev->dev, "found a 16z%03u with %u ports\n",
89		mdev->id, num_ports);
90
91	if (num_ports <= 0 || num_ports > 4) {
92		dev_err(&mdev->dev, "unexpected number of ports: %u\n",
93			num_ports);
94		return -ENODEV;
95	}
96
97	data = devm_kcalloc(&mdev->dev, num_ports,
98			    sizeof(struct serial_8250_men_mcb_data),
99			    GFP_KERNEL);
100	if (!data)
101		return -ENOMEM;
102
103	mcb_set_drvdata(mdev, data);
104
105	for (i = 0; i < num_ports; i++) {
106		data[i].uart.port.dev = mdev->dma_dev;
107		spin_lock_init(&data[i].uart.port.lock);
108
109		data[i].uart.port.type = PORT_16550;
110		data[i].uart.port.flags = UPF_SKIP_TEST | UPF_SHARE_IRQ
111					  | UPF_FIXED_TYPE;
112		data[i].uart.port.iotype = UPIO_MEM;
113		data[i].uart.port.uartclk = men_lookup_uartclk(mdev);
114		data[i].uart.port.regshift = 0;
115		data[i].uart.port.irq = mcb_get_irq(mdev);
116		data[i].uart.port.membase = membase;
117		data[i].uart.port.fifosize = 60;
118		data[i].uart.port.mapbase = (unsigned long) mem->start
119					    + i * MEN_UART_MEM_SIZE;
120		data[i].uart.port.iobase = data[i].uart.port.mapbase;
121
122		/* ok, register the port */
123		data[i].line = serial8250_register_8250_port(&data[i].uart);
124		if (data[i].line < 0) {
125			dev_err(&mdev->dev, "unable to register UART port\n");
126			return data[i].line;
127		}
128		dev_info(&mdev->dev, "found MCB UART: ttyS%d\n", data[i].line);
129	}
130
131	return 0;
132}
133
134static void serial_8250_men_mcb_remove(struct mcb_device *mdev)
135{
136	int num_ports, i;
137	struct serial_8250_men_mcb_data *data = mcb_get_drvdata(mdev);
138
139	if (!data)
140		return;
141
142	num_ports = get_num_ports(mdev, data[0].uart.port.membase);
143	if (num_ports <= 0 || num_ports > 4) {
144		dev_err(&mdev->dev, "error retrieving number of ports!\n");
145		return;
146	}
147
148	for (i = 0; i < num_ports; i++)
149		serial8250_unregister_port(data[i].line);
150}
151
152static const struct mcb_device_id serial_8250_men_mcb_ids[] = {
153	{ .device = MEN_UART_ID_Z025 },
154	{ .device = MEN_UART_ID_Z057 },
155	{ .device = MEN_UART_ID_Z125 },
156	{ }
157};
158MODULE_DEVICE_TABLE(mcb, serial_8250_men_mcb_ids);
159
160static struct mcb_driver mcb_driver = {
161	.driver = {
162		.name = "8250_men_mcb",
163		.owner = THIS_MODULE,
164	},
165	.probe = serial_8250_men_mcb_probe,
166	.remove = serial_8250_men_mcb_remove,
167	.id_table = serial_8250_men_mcb_ids,
168};
169module_mcb_driver(mcb_driver);
170
171MODULE_LICENSE("GPL v2");
172MODULE_DESCRIPTION("MEN 8250 UART driver");
173MODULE_AUTHOR("Michael Moese <michael.moese@men.de");
174MODULE_ALIAS("mcb:16z125");
175MODULE_ALIAS("mcb:16z025");
176MODULE_ALIAS("mcb:16z057");
177MODULE_IMPORT_NS(MCB);
178