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
early_in(struct uart_port * port,int offset)44 static uint8_t early_in(struct uart_port *port, int offset)
45 {
46 return readl(port->membase + (offset << 2));
47 }
48
early_out(struct uart_port * port,int offset,uint8_t value)49 static void early_out(struct uart_port *port, int offset, uint8_t value)
50 {
51 writel(value, port->membase + (offset << 2));
52 }
53
ingenic_early_console_putc(struct uart_port * port,unsigned char c)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
ingenic_early_console_write(struct console * console,const char * s,unsigned int count)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
ingenic_early_console_setup_clock(struct earlycon_device * dev)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
ingenic_earlycon_setup_tail(struct earlycon_device * dev,const char * opt)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
ingenic_early_console_setup(struct earlycon_device * dev,const char * opt)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
jz4750_early_console_setup(struct earlycon_device * dev,const char * opt)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
ingenic_uart_serial_out(struct uart_port * p,int offset,int value)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
ingenic_uart_serial_in(struct uart_port * p,int offset)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
ingenic_uart_probe(struct platform_device * pdev)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 err;
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 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
246 if (!regs) {
247 dev_err(&pdev->dev, "no registers defined\n");
248 return -EINVAL;
249 }
250
251 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
252 if (!data)
253 return -ENOMEM;
254
255 spin_lock_init(&uart.port.lock);
256 uart.port.type = PORT_16550A;
257 uart.port.flags = UPF_SKIP_TEST | UPF_IOREMAP | UPF_FIXED_TYPE;
258 uart.port.mapbase = regs->start;
259 uart.port.serial_out = ingenic_uart_serial_out;
260 uart.port.serial_in = ingenic_uart_serial_in;
261 uart.port.dev = &pdev->dev;
262 uart.tx_loadsz = cdata->tx_loadsz;
263 uart.capabilities = UART_CAP_FIFO | UART_CAP_RTOIE;
264
265 err = uart_read_port_properties(&uart.port);
266 if (err)
267 return err;
268
269 uart.port.regshift = 2;
270 uart.port.fifosize = cdata->fifosize;
271
272 uart.port.membase = devm_ioremap(&pdev->dev, regs->start,
273 resource_size(regs));
274 if (!uart.port.membase)
275 return -ENOMEM;
276
277 data->clk_module = devm_clk_get(&pdev->dev, "module");
278 if (IS_ERR(data->clk_module))
279 return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_module),
280 "unable to get module clock\n");
281
282 data->clk_baud = devm_clk_get(&pdev->dev, "baud");
283 if (IS_ERR(data->clk_baud))
284 return dev_err_probe(&pdev->dev, PTR_ERR(data->clk_baud),
285 "unable to get baud clock\n");
286
287 err = clk_prepare_enable(data->clk_module);
288 if (err) {
289 dev_err(&pdev->dev, "could not enable module clock: %d\n", err);
290 goto out;
291 }
292
293 err = clk_prepare_enable(data->clk_baud);
294 if (err) {
295 dev_err(&pdev->dev, "could not enable baud clock: %d\n", err);
296 goto out_disable_moduleclk;
297 }
298 uart.port.uartclk = clk_get_rate(data->clk_baud);
299
300 data->line = serial8250_register_8250_port(&uart);
301 if (data->line < 0) {
302 err = data->line;
303 goto out_disable_baudclk;
304 }
305
306 platform_set_drvdata(pdev, data);
307 return 0;
308
309 out_disable_baudclk:
310 clk_disable_unprepare(data->clk_baud);
311 out_disable_moduleclk:
312 clk_disable_unprepare(data->clk_module);
313 out:
314 return err;
315 }
316
ingenic_uart_remove(struct platform_device * pdev)317 static void ingenic_uart_remove(struct platform_device *pdev)
318 {
319 struct ingenic_uart_data *data = platform_get_drvdata(pdev);
320
321 serial8250_unregister_port(data->line);
322 clk_disable_unprepare(data->clk_module);
323 clk_disable_unprepare(data->clk_baud);
324 }
325
326 static const struct ingenic_uart_config jz4740_uart_config = {
327 .tx_loadsz = 8,
328 .fifosize = 16,
329 };
330
331 static const struct ingenic_uart_config jz4760_uart_config = {
332 .tx_loadsz = 16,
333 .fifosize = 32,
334 };
335
336 static const struct ingenic_uart_config jz4780_uart_config = {
337 .tx_loadsz = 32,
338 .fifosize = 64,
339 };
340
341 static const struct ingenic_uart_config x1000_uart_config = {
342 .tx_loadsz = 32,
343 .fifosize = 64,
344 };
345
346 static const struct of_device_id of_match[] = {
347 { .compatible = "ingenic,jz4740-uart", .data = &jz4740_uart_config },
348 { .compatible = "ingenic,jz4750-uart", .data = &jz4760_uart_config },
349 { .compatible = "ingenic,jz4760-uart", .data = &jz4760_uart_config },
350 { .compatible = "ingenic,jz4770-uart", .data = &jz4760_uart_config },
351 { .compatible = "ingenic,jz4775-uart", .data = &jz4760_uart_config },
352 { .compatible = "ingenic,jz4780-uart", .data = &jz4780_uart_config },
353 { .compatible = "ingenic,x1000-uart", .data = &x1000_uart_config },
354 { /* sentinel */ }
355 };
356 MODULE_DEVICE_TABLE(of, of_match);
357
358 static struct platform_driver ingenic_uart_platform_driver = {
359 .driver = {
360 .name = "ingenic-uart",
361 .of_match_table = of_match,
362 },
363 .probe = ingenic_uart_probe,
364 .remove_new = ingenic_uart_remove,
365 };
366
367 module_platform_driver(ingenic_uart_platform_driver);
368
369 MODULE_AUTHOR("Paul Burton");
370 MODULE_LICENSE("GPL");
371 MODULE_DESCRIPTION("Ingenic SoC UART driver");
372