1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2010 Lars-Peter Clausen <lars@metafoo.de>
4  * Copyright (C) 2015 Imagination Technologies
5  *
6  * Ingenic SoC UART support
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/console.h>
11 #include <linux/io.h>
12 #include <linux/libfdt.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/of_fdt.h>
16 #include <linux/of_device.h>
17 #include <linux/platform_device.h>
18 #include <linux/serial_8250.h>
19 #include <linux/serial_core.h>
20 #include <linux/serial_reg.h>
21 
22 #include "8250.h"
23 
24 /** ingenic_uart_config: SOC specific config data. */
25 struct ingenic_uart_config {
26 	int tx_loadsz;
27 	int fifosize;
28 };
29 
30 struct ingenic_uart_data {
31 	struct clk	*clk_module;
32 	struct clk	*clk_baud;
33 	int		line;
34 };
35 
36 static const struct of_device_id of_match[];
37 
38 #define UART_FCR_UME	BIT(4)
39 
40 #define UART_MCR_MDCE	BIT(7)
41 #define UART_MCR_FCM	BIT(6)
42 
43 static struct earlycon_device *early_device;
44 
45 static uint8_t early_in(struct uart_port *port, int offset)
46 {
47 	return readl(port->membase + (offset << 2));
48 }
49 
50 static void early_out(struct uart_port *port, int offset, uint8_t value)
51 {
52 	writel(value, port->membase + (offset << 2));
53 }
54 
55 static void ingenic_early_console_putc(struct uart_port *port, int c)
56 {
57 	uint8_t lsr;
58 
59 	do {
60 		lsr = early_in(port, UART_LSR);
61 	} while ((lsr & UART_LSR_TEMT) == 0);
62 
63 	early_out(port, UART_TX, c);
64 }
65 
66 static void ingenic_early_console_write(struct console *console,
67 					      const char *s, unsigned int count)
68 {
69 	uart_console_write(&early_device->port, s, count,
70 			   ingenic_early_console_putc);
71 }
72 
73 static void __init ingenic_early_console_setup_clock(struct earlycon_device *dev)
74 {
75 	void *fdt = initial_boot_params;
76 	const __be32 *prop;
77 	int offset;
78 
79 	offset = fdt_path_offset(fdt, "/ext");
80 	if (offset < 0)
81 		return;
82 
83 	prop = fdt_getprop(fdt, offset, "clock-frequency", NULL);
84 	if (!prop)
85 		return;
86 
87 	dev->port.uartclk = be32_to_cpup(prop);
88 }
89 
90 static int __init ingenic_early_console_setup(struct earlycon_device *dev,
91 					      const char *opt)
92 {
93 	struct uart_port *port = &dev->port;
94 	unsigned int divisor;
95 	int baud = 115200;
96 
97 	if (!dev->port.membase)
98 		return -ENODEV;
99 
100 	if (opt) {
101 		unsigned int parity, bits, flow; /* unused for now */
102 
103 		uart_parse_options(opt, &baud, &parity, &bits, &flow);
104 	}
105 
106 	ingenic_early_console_setup_clock(dev);
107 
108 	if (dev->baud)
109 		baud = dev->baud;
110 	divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
111 
112 	early_out(port, UART_IER, 0);
113 	early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
114 	early_out(port, UART_DLL, 0);
115 	early_out(port, UART_DLM, 0);
116 	early_out(port, UART_LCR, UART_LCR_WLEN8);
117 	early_out(port, UART_FCR, UART_FCR_UME | UART_FCR_CLEAR_XMIT |
118 			UART_FCR_CLEAR_RCVR | UART_FCR_ENABLE_FIFO);
119 	early_out(port, UART_MCR, UART_MCR_RTS | UART_MCR_DTR);
120 
121 	early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
122 	early_out(port, UART_DLL, divisor & 0xff);
123 	early_out(port, UART_DLM, (divisor >> 8) & 0xff);
124 	early_out(port, UART_LCR, UART_LCR_WLEN8);
125 
126 	early_device = dev;
127 	dev->con->write = ingenic_early_console_write;
128 
129 	return 0;
130 }
131 
132 OF_EARLYCON_DECLARE(jz4740_uart, "ingenic,jz4740-uart",
133 		    ingenic_early_console_setup);
134 
135 OF_EARLYCON_DECLARE(jz4770_uart, "ingenic,jz4770-uart",
136 		    ingenic_early_console_setup);
137 
138 OF_EARLYCON_DECLARE(jz4775_uart, "ingenic,jz4775-uart",
139 		    ingenic_early_console_setup);
140 
141 OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart",
142 		    ingenic_early_console_setup);
143 
144 OF_EARLYCON_DECLARE(x1000_uart, "ingenic,x1000-uart",
145 		    ingenic_early_console_setup);
146 
147 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
148 {
149 	int ier;
150 
151 	switch (offset) {
152 	case UART_FCR:
153 		/* UART module enable */
154 		value |= UART_FCR_UME;
155 		break;
156 
157 	case UART_IER:
158 		/*
159 		 * Enable receive timeout interrupt with the receive line
160 		 * status interrupt.
161 		 */
162 		value |= (value & 0x4) << 2;
163 		break;
164 
165 	case UART_MCR:
166 		/*
167 		 * If we have enabled modem status IRQs we should enable
168 		 * modem mode.
169 		 */
170 		ier = p->serial_in(p, UART_IER);
171 
172 		if (ier & UART_IER_MSI)
173 			value |= UART_MCR_MDCE | UART_MCR_FCM;
174 		else
175 			value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
176 		break;
177 
178 	default:
179 		break;
180 	}
181 
182 	writeb(value, p->membase + (offset << p->regshift));
183 }
184 
185 static unsigned int ingenic_uart_serial_in(struct uart_port *p, int offset)
186 {
187 	unsigned int value;
188 
189 	value = readb(p->membase + (offset << p->regshift));
190 
191 	/* Hide non-16550 compliant bits from higher levels */
192 	switch (offset) {
193 	case UART_FCR:
194 		value &= ~UART_FCR_UME;
195 		break;
196 
197 	case UART_MCR:
198 		value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
199 		break;
200 
201 	default:
202 		break;
203 	}
204 	return value;
205 }
206 
207 static int ingenic_uart_probe(struct platform_device *pdev)
208 {
209 	struct uart_8250_port uart = {};
210 	struct ingenic_uart_data *data;
211 	const struct ingenic_uart_config *cdata;
212 	const struct of_device_id *match;
213 	struct resource *regs;
214 	int irq, err, line;
215 
216 	match = of_match_device(of_match, &pdev->dev);
217 	if (!match) {
218 		dev_err(&pdev->dev, "Error: No device match found\n");
219 		return -ENODEV;
220 	}
221 	cdata = match->data;
222 
223 	irq = platform_get_irq(pdev, 0);
224 	if (irq < 0)
225 		return irq;
226 
227 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
228 	if (!regs) {
229 		dev_err(&pdev->dev, "no registers defined\n");
230 		return -EINVAL;
231 	}
232 
233 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
234 	if (!data)
235 		return -ENOMEM;
236 
237 	spin_lock_init(&uart.port.lock);
238 	uart.port.type = PORT_16550A;
239 	uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
240 	uart.port.iotype = UPIO_MEM;
241 	uart.port.mapbase = regs->start;
242 	uart.port.regshift = 2;
243 	uart.port.serial_out = ingenic_uart_serial_out;
244 	uart.port.serial_in = ingenic_uart_serial_in;
245 	uart.port.irq = irq;
246 	uart.port.dev = &pdev->dev;
247 	uart.port.fifosize = cdata->fifosize;
248 	uart.tx_loadsz = cdata->tx_loadsz;
249 	uart.capabilities = UART_CAP_FIFO | UART_CAP_RTOIE;
250 
251 	/* Check for a fixed line number */
252 	line = of_alias_get_id(pdev->dev.of_node, "serial");
253 	if (line >= 0)
254 		uart.port.line = line;
255 
256 	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
257 					 resource_size(regs));
258 	if (!uart.port.membase)
259 		return -ENOMEM;
260 
261 	data->clk_module = devm_clk_get(&pdev->dev, "module");
262 	if (IS_ERR(data->clk_module))
263 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_module),
264 				     "unable to get module clock\n");
265 
266 	data->clk_baud = devm_clk_get(&pdev->dev, "baud");
267 	if (IS_ERR(data->clk_baud))
268 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_baud),
269 				     "unable to get baud clock\n");
270 
271 	err = clk_prepare_enable(data->clk_module);
272 	if (err) {
273 		dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
274 		goto out;
275 	}
276 
277 	err = clk_prepare_enable(data->clk_baud);
278 	if (err) {
279 		dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
280 		goto out_disable_moduleclk;
281 	}
282 	uart.port.uartclk = clk_get_rate(data->clk_baud);
283 
284 	data->line = serial8250_register_8250_port(&uart);
285 	if (data->line < 0) {
286 		err = data->line;
287 		goto out_disable_baudclk;
288 	}
289 
290 	platform_set_drvdata(pdev, data);
291 	return 0;
292 
293 out_disable_baudclk:
294 	clk_disable_unprepare(data->clk_baud);
295 out_disable_moduleclk:
296 	clk_disable_unprepare(data->clk_module);
297 out:
298 	return err;
299 }
300 
301 static int ingenic_uart_remove(struct platform_device *pdev)
302 {
303 	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
304 
305 	serial8250_unregister_port(data->line);
306 	clk_disable_unprepare(data->clk_module);
307 	clk_disable_unprepare(data->clk_baud);
308 	return 0;
309 }
310 
311 static const struct ingenic_uart_config jz4740_uart_config = {
312 	.tx_loadsz = 8,
313 	.fifosize = 16,
314 };
315 
316 static const struct ingenic_uart_config jz4760_uart_config = {
317 	.tx_loadsz = 16,
318 	.fifosize = 32,
319 };
320 
321 static const struct ingenic_uart_config jz4780_uart_config = {
322 	.tx_loadsz = 32,
323 	.fifosize = 64,
324 };
325 
326 static const struct ingenic_uart_config x1000_uart_config = {
327 	.tx_loadsz = 32,
328 	.fifosize = 64,
329 };
330 
331 static const struct of_device_id of_match[] = {
332 	{ .compatible = "ingenic,jz4740-uart", .data = &jz4740_uart_config },
333 	{ .compatible = "ingenic,jz4760-uart", .data = &jz4760_uart_config },
334 	{ .compatible = "ingenic,jz4770-uart", .data = &jz4760_uart_config },
335 	{ .compatible = "ingenic,jz4775-uart", .data = &jz4760_uart_config },
336 	{ .compatible = "ingenic,jz4780-uart", .data = &jz4780_uart_config },
337 	{ .compatible = "ingenic,x1000-uart", .data = &x1000_uart_config },
338 	{ /* sentinel */ }
339 };
340 MODULE_DEVICE_TABLE(of, of_match);
341 
342 static struct platform_driver ingenic_uart_platform_driver = {
343 	.driver = {
344 		.name		= "ingenic-uart",
345 		.of_match_table	= of_match,
346 	},
347 	.probe			= ingenic_uart_probe,
348 	.remove			= ingenic_uart_remove,
349 };
350 
351 module_platform_driver(ingenic_uart_platform_driver);
352 
353 MODULE_AUTHOR("Paul Burton");
354 MODULE_LICENSE("GPL");
355 MODULE_DESCRIPTION("Ingenic SoC UART driver");
356