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 EARLYCON_DECLARE(jz4740_uart, ingenic_early_console_setup);
133 OF_EARLYCON_DECLARE(jz4740_uart, "ingenic,jz4740-uart",
134 		    ingenic_early_console_setup);
135 
136 EARLYCON_DECLARE(jz4770_uart, ingenic_early_console_setup);
137 OF_EARLYCON_DECLARE(jz4770_uart, "ingenic,jz4770-uart",
138 		    ingenic_early_console_setup);
139 
140 EARLYCON_DECLARE(jz4775_uart, ingenic_early_console_setup);
141 OF_EARLYCON_DECLARE(jz4775_uart, "ingenic,jz4775-uart",
142 		    ingenic_early_console_setup);
143 
144 EARLYCON_DECLARE(jz4780_uart, ingenic_early_console_setup);
145 OF_EARLYCON_DECLARE(jz4780_uart, "ingenic,jz4780-uart",
146 		    ingenic_early_console_setup);
147 
148 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
149 {
150 	int ier;
151 
152 	switch (offset) {
153 	case UART_FCR:
154 		/* UART module enable */
155 		value |= UART_FCR_UME;
156 		break;
157 
158 	case UART_IER:
159 		/*
160 		 * Enable receive timeout interrupt with the receive line
161 		 * status interrupt.
162 		 */
163 		value |= (value & 0x4) << 2;
164 		break;
165 
166 	case UART_MCR:
167 		/*
168 		 * If we have enabled modem status IRQs we should enable
169 		 * modem mode.
170 		 */
171 		ier = p->serial_in(p, UART_IER);
172 
173 		if (ier & UART_IER_MSI)
174 			value |= UART_MCR_MDCE | UART_MCR_FCM;
175 		else
176 			value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
177 		break;
178 
179 	default:
180 		break;
181 	}
182 
183 	writeb(value, p->membase + (offset << p->regshift));
184 }
185 
186 static unsigned int ingenic_uart_serial_in(struct uart_port *p, int offset)
187 {
188 	unsigned int value;
189 
190 	value = readb(p->membase + (offset << p->regshift));
191 
192 	/* Hide non-16550 compliant bits from higher levels */
193 	switch (offset) {
194 	case UART_FCR:
195 		value &= ~UART_FCR_UME;
196 		break;
197 
198 	case UART_MCR:
199 		value &= ~(UART_MCR_MDCE | UART_MCR_FCM);
200 		break;
201 
202 	default:
203 		break;
204 	}
205 	return value;
206 }
207 
208 static int ingenic_uart_probe(struct platform_device *pdev)
209 {
210 	struct uart_8250_port uart = {};
211 	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
212 	struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
213 	struct ingenic_uart_data *data;
214 	const struct ingenic_uart_config *cdata;
215 	const struct of_device_id *match;
216 	int err, line;
217 
218 	match = of_match_device(of_match, &pdev->dev);
219 	if (!match) {
220 		dev_err(&pdev->dev, "Error: No device match found\n");
221 		return -ENODEV;
222 	}
223 	cdata = match->data;
224 
225 	if (!regs || !irq) {
226 		dev_err(&pdev->dev, "no registers/irq defined\n");
227 		return -EINVAL;
228 	}
229 
230 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
231 	if (!data)
232 		return -ENOMEM;
233 
234 	spin_lock_init(&uart.port.lock);
235 	uart.port.type = PORT_16550A;
236 	uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
237 	uart.port.iotype = UPIO_MEM;
238 	uart.port.mapbase = regs->start;
239 	uart.port.regshift = 2;
240 	uart.port.serial_out = ingenic_uart_serial_out;
241 	uart.port.serial_in = ingenic_uart_serial_in;
242 	uart.port.irq = irq->start;
243 	uart.port.dev = &pdev->dev;
244 	uart.port.fifosize = cdata->fifosize;
245 	uart.tx_loadsz = cdata->tx_loadsz;
246 	uart.capabilities = UART_CAP_FIFO | UART_CAP_RTOIE;
247 
248 	/* Check for a fixed line number */
249 	line = of_alias_get_id(pdev->dev.of_node, "serial");
250 	if (line >= 0)
251 		uart.port.line = line;
252 
253 	uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
254 					 resource_size(regs));
255 	if (!uart.port.membase)
256 		return -ENOMEM;
257 
258 	data->clk_module = devm_clk_get(&pdev->dev, "module");
259 	if (IS_ERR(data->clk_module)) {
260 		err = PTR_ERR(data->clk_module);
261 		if (err != -EPROBE_DEFER)
262 			dev_err(&pdev->dev,
263 				"unable to get module clock: %d\n", err);
264 		return err;
265 	}
266 
267 	data->clk_baud = devm_clk_get(&pdev->dev, "baud");
268 	if (IS_ERR(data->clk_baud)) {
269 		err = PTR_ERR(data->clk_baud);
270 		if (err != -EPROBE_DEFER)
271 			dev_err(&pdev->dev,
272 				"unable to get baud clock: %d\n", err);
273 		return err;
274 	}
275 
276 	err = clk_prepare_enable(data->clk_module);
277 	if (err) {
278 		dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
279 		goto out;
280 	}
281 
282 	err = clk_prepare_enable(data->clk_baud);
283 	if (err) {
284 		dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
285 		goto out_disable_moduleclk;
286 	}
287 	uart.port.uartclk = clk_get_rate(data->clk_baud);
288 
289 	data->line = serial8250_register_8250_port(&uart);
290 	if (data->line < 0) {
291 		err = data->line;
292 		goto out_disable_baudclk;
293 	}
294 
295 	platform_set_drvdata(pdev, data);
296 	return 0;
297 
298 out_disable_baudclk:
299 	clk_disable_unprepare(data->clk_baud);
300 out_disable_moduleclk:
301 	clk_disable_unprepare(data->clk_module);
302 out:
303 	return err;
304 }
305 
306 static int ingenic_uart_remove(struct platform_device *pdev)
307 {
308 	struct ingenic_uart_data *data = platform_get_drvdata(pdev);
309 
310 	serial8250_unregister_port(data->line);
311 	clk_disable_unprepare(data->clk_module);
312 	clk_disable_unprepare(data->clk_baud);
313 	return 0;
314 }
315 
316 static const struct ingenic_uart_config jz4740_uart_config = {
317 	.tx_loadsz = 8,
318 	.fifosize = 16,
319 };
320 
321 static const struct ingenic_uart_config jz4760_uart_config = {
322 	.tx_loadsz = 16,
323 	.fifosize = 32,
324 };
325 
326 static const struct ingenic_uart_config jz4780_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 	{ /* sentinel */ }
338 };
339 MODULE_DEVICE_TABLE(of, of_match);
340 
341 static struct platform_driver ingenic_uart_platform_driver = {
342 	.driver = {
343 		.name		= "ingenic-uart",
344 		.of_match_table	= of_match,
345 	},
346 	.probe			= ingenic_uart_probe,
347 	.remove			= ingenic_uart_remove,
348 };
349 
350 module_platform_driver(ingenic_uart_platform_driver);
351 
352 MODULE_AUTHOR("Paul Burton");
353 MODULE_LICENSE("GPL");
354 MODULE_DESCRIPTION("Ingenic SoC UART driver");
355