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/platform_device.h>
17 #include <linux/serial_8250.h>
18 #include <linux/serial_core.h>
19 #include <linux/serial_reg.h>
20 
21 #include "8250.h"
22 
23 /** ingenic_uart_config: SOC specific config data. */
24 struct ingenic_uart_config {
25 	int tx_loadsz;
26 	int fifosize;
27 };
28 
29 struct ingenic_uart_data {
30 	struct clk	*clk_module;
31 	struct clk	*clk_baud;
32 	int		line;
33 };
34 
35 static const struct of_device_id of_match[];
36 
37 #define UART_FCR_UME	BIT(4)
38 
39 #define UART_MCR_MDCE	BIT(7)
40 #define UART_MCR_FCM	BIT(6)
41 
42 static struct earlycon_device *early_device;
43 
44 static uint8_t early_in(struct uart_port *port, int offset)
45 {
46 	return readl(port->membase + (offset << 2));
47 }
48 
49 static void early_out(struct uart_port *port, int offset, uint8_t value)
50 {
51 	writel(value, port->membase + (offset << 2));
52 }
53 
54 static void ingenic_early_console_putc(struct uart_port *port, unsigned char c)
55 {
56 	u16 lsr;
57 
58 	do {
59 		lsr = early_in(port, UART_LSR);
60 	} while ((lsr & UART_LSR_TEMT) == 0);
61 
62 	early_out(port, UART_TX, c);
63 }
64 
65 static void ingenic_early_console_write(struct console *console,
66 					      const char *s, unsigned int count)
67 {
68 	uart_console_write(&early_device->port, s, count,
69 			   ingenic_early_console_putc);
70 }
71 
72 static void __init ingenic_early_console_setup_clock(struct earlycon_device *dev)
73 {
74 	void *fdt = initial_boot_params;
75 	const __be32 *prop;
76 	int offset;
77 
78 	offset = fdt_path_offset(fdt, "/ext");
79 	if (offset < 0)
80 		return;
81 
82 	prop = fdt_getprop(fdt, offset, "clock-frequency", NULL);
83 	if (!prop)
84 		return;
85 
86 	dev->port.uartclk = be32_to_cpup(prop);
87 }
88 
89 static int __init ingenic_earlycon_setup_tail(struct earlycon_device *dev,
90 					      const char *opt)
91 {
92 	struct uart_port *port = &dev->port;
93 	unsigned int divisor;
94 	int baud = 115200;
95 
96 	if (!dev->port.membase)
97 		return -ENODEV;
98 
99 	if (opt) {
100 		unsigned int parity, bits, flow; /* unused for now */
101 
102 		uart_parse_options(opt, &baud, &parity, &bits, &flow);
103 	}
104 
105 	if (dev->baud)
106 		baud = dev->baud;
107 	divisor = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
108 
109 	early_out(port, UART_IER, 0);
110 	early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
111 	early_out(port, UART_DLL, 0);
112 	early_out(port, UART_DLM, 0);
113 	early_out(port, UART_LCR, UART_LCR_WLEN8);
114 	early_out(port, UART_FCR, UART_FCR_UME | UART_FCR_CLEAR_XMIT |
115 			UART_FCR_CLEAR_RCVR | UART_FCR_ENABLE_FIFO);
116 	early_out(port, UART_MCR, UART_MCR_RTS | UART_MCR_DTR);
117 
118 	early_out(port, UART_LCR, UART_LCR_DLAB | UART_LCR_WLEN8);
119 	early_out(port, UART_DLL, divisor & 0xff);
120 	early_out(port, UART_DLM, (divisor >> 8) & 0xff);
121 	early_out(port, UART_LCR, UART_LCR_WLEN8);
122 
123 	early_device = dev;
124 	dev->con->write = ingenic_early_console_write;
125 
126 	return 0;
127 }
128 
129 static int __init ingenic_early_console_setup(struct earlycon_device *dev,
130 					      const char *opt)
131 {
132 	ingenic_early_console_setup_clock(dev);
133 
134 	return ingenic_earlycon_setup_tail(dev, opt);
135 }
136 
137 static int __init jz4750_early_console_setup(struct earlycon_device *dev,
138 					     const char *opt)
139 {
140 	/*
141 	 * JZ4750/55/60 have an optional /2 divider between the EXT
142 	 * oscillator and some peripherals including UART, which will
143 	 * be enabled if using a 24 MHz oscillator, and disabled when
144 	 * using a 12 MHz oscillator.
145 	 */
146 	ingenic_early_console_setup_clock(dev);
147 	if (dev->port.uartclk >= 16000000)
148 		dev->port.uartclk /= 2;
149 
150 	return ingenic_earlycon_setup_tail(dev, opt);
151 }
152 
153 OF_EARLYCON_DECLARE(jz4740_uart, "ingenic,jz4740-uart",
154 		    ingenic_early_console_setup);
155 
156 OF_EARLYCON_DECLARE(jz4750_uart, "ingenic,jz4750-uart",
157 		    jz4750_early_console_setup);
158 
159 OF_EARLYCON_DECLARE(jz4770_uart, "ingenic,jz4770-uart",
160 		    ingenic_early_console_setup);
161 
162 OF_EARLYCON_DECLARE(jz4775_uart, "ingenic,jz4775-uart",
163 		    ingenic_early_console_setup);
164 
165 OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart",
166 		    ingenic_early_console_setup);
167 
168 OF_EARLYCON_DECLARE(x1000_uart, "ingenic,x1000-uart",
169 		    ingenic_early_console_setup);
170 
171 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
172 {
173 	int ier;
174 
175 	switch (offset) {
176 	case UART_FCR:
177 		/* UART module enable */
178 		value |= UART_FCR_UME;
179 		break;
180 
181 	case UART_IER:
182 		/*
183 		 * Enable receive timeout interrupt with the receive line
184 		 * status interrupt.
185 		 */
186 		value |= (value & 0x4) << 2;
187 		break;
188 
189 	case UART_MCR:
190 		/*
191 		 * If we have enabled modem status IRQs we should enable
192 		 * modem mode.
193 		 */
194 		ier = p->serial_in(p, UART_IER);
195 
196 		if (ier & UART_IER_MSI)
197 			value |= UART_MCR_MDCE | UART_MCR_FCM;
198 		else
199 			value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
200 		break;
201 
202 	default:
203 		break;
204 	}
205 
206 	writeb(value, p->membase + (offset << p->regshift));
207 }
208 
209 static unsigned int ingenic_uart_serial_in(struct uart_port *p, int offset)
210 {
211 	unsigned int value;
212 
213 	value = readb(p->membase + (offset << p->regshift));
214 
215 	/* Hide non-16550 compliant bits from higher levels */
216 	switch (offset) {
217 	case UART_FCR:
218 		value &= ~UART_FCR_UME;
219 		break;
220 
221 	case UART_MCR:
222 		value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
223 		break;
224 
225 	default:
226 		break;
227 	}
228 	return value;
229 }
230 
231 static int ingenic_uart_probe(struct platform_device *pdev)
232 {
233 	struct uart_8250_port uart = {};
234 	struct ingenic_uart_data *data;
235 	const struct ingenic_uart_config *cdata;
236 	struct resource *regs;
237 	int irq, err, line;
238 
239 	cdata = of_device_get_match_data(&pdev->dev);
240 	if (!cdata) {
241 		dev_err(&pdev->dev, "Error: No device match found\n");
242 		return -ENODEV;
243 	}
244 
245 	irq = platform_get_irq(pdev, 0);
246 	if (irq < 0)
247 		return irq;
248 
249 	regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
250 	if (!regs) {
251 		dev_err(&pdev->dev, "no registers defined\n");
252 		return -EINVAL;
253 	}
254 
255 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
256 	if (!data)
257 		return -ENOMEM;
258 
259 	spin_lock_init(&uart.port.lock);
260 	uart.port.type = PORT_16550A;
261 	uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
262 	uart.port.iotype = UPIO_MEM;
263 	uart.port.mapbase = regs->start;
264 	uart.port.regshift = 2;
265 	uart.port.serial_out = ingenic_uart_serial_out;
266 	uart.port.serial_in = ingenic_uart_serial_in;
267 	uart.port.irq = irq;
268 	uart.port.dev = &pdev->dev;
269 	uart.port.fifosize = cdata->fifosize;
270 	uart.tx_loadsz = cdata->tx_loadsz;
271 	uart.capabilities = UART_CAP_FIFO | UART_CAP_RTOIE;
272 
273 	/* Check for a fixed line number */
274 	line = of_alias_get_id(pdev->dev.of_node, "serial");
275 	if (line >= 0)
276 		uart.port.line = line;
277 
278 	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
279 					 resource_size(regs));
280 	if (!uart.port.membase)
281 		return -ENOMEM;
282 
283 	data->clk_module = devm_clk_get(&pdev->dev, "module");
284 	if (IS_ERR(data->clk_module))
285 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_module),
286 				     "unable to get module clock\n");
287 
288 	data->clk_baud = devm_clk_get(&pdev->dev, "baud");
289 	if (IS_ERR(data->clk_baud))
290 		return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_baud),
291 				     "unable to get baud clock\n");
292 
293 	err = clk_prepare_enable(data->clk_module);
294 	if (err) {
295 		dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
296 		goto out;
297 	}
298 
299 	err = clk_prepare_enable(data->clk_baud);
300 	if (err) {
301 		dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
302 		goto out_disable_moduleclk;
303 	}
304 	uart.port.uartclk = clk_get_rate(data->clk_baud);
305 
306 	data->line = serial8250_register_8250_port(&uart);
307 	if (data->line < 0) {
308 		err = data->line;
309 		goto out_disable_baudclk;
310 	}
311 
312 	platform_set_drvdata(pdev, data);
313 	return 0;
314 
315 out_disable_baudclk:
316 	clk_disable_unprepare(data->clk_baud);
317 out_disable_moduleclk:
318 	clk_disable_unprepare(data->clk_module);
319 out:
320 	return err;
321 }
322 
323 static int ingenic_uart_remove(struct platform_device *pdev)
324 {
325 	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
326 
327 	serial8250_unregister_port(data->line);
328 	clk_disable_unprepare(data->clk_module);
329 	clk_disable_unprepare(data->clk_baud);
330 	return 0;
331 }
332 
333 static const struct ingenic_uart_config jz4740_uart_config = {
334 	.tx_loadsz = 8,
335 	.fifosize = 16,
336 };
337 
338 static const struct ingenic_uart_config jz4760_uart_config = {
339 	.tx_loadsz = 16,
340 	.fifosize = 32,
341 };
342 
343 static const struct ingenic_uart_config jz4780_uart_config = {
344 	.tx_loadsz = 32,
345 	.fifosize = 64,
346 };
347 
348 static const struct ingenic_uart_config x1000_uart_config = {
349 	.tx_loadsz = 32,
350 	.fifosize = 64,
351 };
352 
353 static const struct of_device_id of_match[] = {
354 	{ .compatible = "ingenic,jz4740-uart", .data = &jz4740_uart_config },
355 	{ .compatible = "ingenic,jz4750-uart", .data = &jz4760_uart_config },
356 	{ .compatible = "ingenic,jz4760-uart", .data = &jz4760_uart_config },
357 	{ .compatible = "ingenic,jz4770-uart", .data = &jz4760_uart_config },
358 	{ .compatible = "ingenic,jz4775-uart", .data = &jz4760_uart_config },
359 	{ .compatible = "ingenic,jz4780-uart", .data = &jz4780_uart_config },
360 	{ .compatible = "ingenic,x1000-uart", .data = &x1000_uart_config },
361 	{ /* sentinel */ }
362 };
363 MODULE_DEVICE_TABLE(of, of_match);
364 
365 static struct platform_driver ingenic_uart_platform_driver = {
366 	.driver = {
367 		.name		= "ingenic-uart",
368 		.of_match_table	= of_match,
369 	},
370 	.probe			= ingenic_uart_probe,
371 	.remove			= ingenic_uart_remove,
372 };
373 
374 module_platform_driver(ingenic_uart_platform_driver);
375 
376 MODULE_AUTHOR("Paul Burton");
377 MODULE_LICENSE("GPL");
378 MODULE_DESCRIPTION("Ingenic SoC UART driver");
379