summaryrefslogtreecommitdiffstats
path: root/kernel/drivers/tty/serial/8250/8250_dw.c
blob: a5d319e4aae65dad90f64bafd33c2ad02bed7034 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
/*
 * Synopsys DesignWare 8250 driver.
 *
 * Copyright 2011 Picochip, Jamie Iles.
 * Copyright 2013 Intel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
 * LCR is written whilst busy.  If it is, then a busy detect interrupt is
 * raised, the LCR needs to be rewritten and the uart status register read.
 */
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/pm_runtime.h>

#include <asm/byteorder.h>

#include "8250.h"

/* Offsets for the DesignWare specific registers */
#define DW_UART_USR	0x1f /* UART Status Register */
#define DW_UART_CPR	0xf4 /* Component Parameter Register */
#define DW_UART_UCV	0xf8 /* UART Component Version */

/* Component Parameter Register bits */
#define DW_UART_CPR_ABP_DATA_WIDTH	(3 << 0)
#define DW_UART_CPR_AFCE_MODE		(1 << 4)
#define DW_UART_CPR_THRE_MODE		(1 << 5)
#define DW_UART_CPR_SIR_MODE		(1 << 6)
#define DW_UART_CPR_SIR_LP_MODE		(1 << 7)
#define DW_UART_CPR_ADDITIONAL_FEATURES	(1 << 8)
#define DW_UART_CPR_FIFO_ACCESS		(1 << 9)
#define DW_UART_CPR_FIFO_STAT		(1 << 10)
#define DW_UART_CPR_SHADOW		(1 << 11)
#define DW_UART_CPR_ENCODED_PARMS	(1 << 12)
#define DW_UART_CPR_DMA_EXTRA		(1 << 13)
#define DW_UART_CPR_FIFO_MODE		(0xff << 16)
/* Helper for fifo size calculation */
#define DW_UART_CPR_FIFO_SIZE(a)	(((a >> 16) & 0xff) * 16)


struct dw8250_data {
	u8			usr_reg;
	int			line;
	int			msr_mask_on;
	int			msr_mask_off;
	struct clk		*clk;
	struct clk		*pclk;
	struct reset_control	*rst;
	struct uart_8250_dma	dma;

	unsigned int		skip_autocfg:1;
	unsigned int		uart_16550_compatible:1;
};

#define BYT_PRV_CLK			0x800
#define BYT_PRV_CLK_EN			(1 << 0)
#define BYT_PRV_CLK_M_VAL_SHIFT		1
#define BYT_PRV_CLK_N_VAL_SHIFT		16
#define BYT_PRV_CLK_UPDATE		(1 << 31)

static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
{
	struct dw8250_data *d = p->private_data;

	/* Override any modem control signals if needed */
	if (offset == UART_MSR) {
		value |= d->msr_mask_on;
		value &= ~d->msr_mask_off;
	}

	return value;
}

static void dw8250_force_idle(struct uart_port *p)
{
	struct uart_8250_port *up = up_to_u8250p(p);

	serial8250_clear_and_reinit_fifos(up);
	(void)p->serial_in(p, UART_RX);
}

static void dw8250_serial_out(struct uart_port *p, int offset, int value)
{
	writeb(value, p->membase + (offset << p->regshift));

	/* Make sure LCR write wasn't ignored */
	if (offset == UART_LCR) {
		int tries = 1000;
		while (tries--) {
			unsigned int lcr = p->serial_in(p, UART_LCR);
			if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
				return;
			dw8250_force_idle(p);
			writeb(value, p->membase + (UART_LCR << p->regshift));
		}
		/*
		 * FIXME: this deadlocks if port->lock is already held
		 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
		 */
	}
}

static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
{
	unsigned int value = readb(p->membase + (offset << p->regshift));

	return dw8250_modify_msr(p, offset, value);
}

#ifdef CONFIG_64BIT
static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
{
	unsigned int value;

	value = (u8)__raw_readq(p->membase + (offset << p->regshift));

	return dw8250_modify_msr(p, offset, value);
}

static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
{
	value &= 0xff;
	__raw_writeq(value, p->membase + (offset << p->regshift));
	/* Read back to ensure register write ordering. */
	__raw_readq(p->membase + (UART_LCR << p->regshift));

	/* Make sure LCR write wasn't ignored */
	if (offset == UART_LCR) {
		int tries = 1000;
		while (tries--) {
			unsigned int lcr = p->serial_in(p, UART_LCR);
			if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
				return;
			dw8250_force_idle(p);
			__raw_writeq(value & 0xff,
				     p->membase + (UART_LCR << p->regshift));
		}
		/*
		 * FIXME: this deadlocks if port->lock is already held
		 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
		 */
	}
}
#endif /* CONFIG_64BIT */

static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
{
	writel(value, p->membase + (offset << p->regshift));

	/* Make sure LCR write wasn't ignored */
	if (offset == UART_LCR) {
		int tries = 1000;
		while (tries--) {
			unsigned int lcr = p->serial_in(p, UART_LCR);
			if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
				return;
			dw8250_force_idle(p);
			writel(value, p->membase + (UART_LCR << p->regshift));
		}
		/*
		 * FIXME: this deadlocks if port->lock is already held
		 * dev_err(p->dev, "Couldn't set LCR to %d\n", value);
		 */
	}
}

static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
{
	unsigned int value = readl(p->membase + (offset << p->regshift));

	return dw8250_modify_msr(p, offset, value);
}

static int dw8250_handle_irq(struct uart_port *p)
{
	struct dw8250_data *d = p->private_data;
	unsigned int iir = p->serial_in(p, UART_IIR);

	if (serial8250_handle_irq(p, iir)) {
		return 1;
	} else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
		/* Clear the USR */
		(void)p->serial_in(p, d->usr_reg);

		return 1;
	}

	return 0;
}

static void
dw8250_do_pm(struct uart_port *port, unsigned int state, unsigned int old)
{
	if (!state)
		pm_runtime_get_sync(port->dev);

	serial8250_do_pm(port, state, old);

	if (state)
		pm_runtime_put_sync_suspend(port->dev);
}

static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios,
			       struct ktermios *old)
{
	unsigned int baud = tty_termios_baud_rate(termios);
	struct dw8250_data *d = p->private_data;
	unsigned int rate;
	int ret;

	if (IS_ERR(d->clk) || !old)
		goto out;

	clk_disable_unprepare(d->clk);
	rate = clk_round_rate(d->clk, baud * 16);
	ret = clk_set_rate(d->clk, rate);
	clk_prepare_enable(d->clk);

	if (!ret)
		p->uartclk = rate;

	p->status &= ~UPSTAT_AUTOCTS;
	if (termios->c_cflag & CRTSCTS)
		p->status |= UPSTAT_AUTOCTS;

out:
	serial8250_do_set_termios(p, termios, old);
}

/*
 * dw8250_fallback_dma_filter will prevent the UART from getting just any free
 * channel on platforms that have DMA engines, but don't have any channels
 * assigned to the UART.
 *
 * REVISIT: This is a work around for limitation in the DMA Engine API. Once the
 * core problem is fixed, this function is no longer needed.
 */
static bool dw8250_fallback_dma_filter(struct dma_chan *chan, void *param)
{
	return false;
}

static bool dw8250_idma_filter(struct dma_chan *chan, void *param)
{
	return param == chan->device->dev->parent;
}

static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
{
	if (p->dev->of_node) {
		struct device_node *np = p->dev->of_node;
		int id;

		/* get index of serial line, if found in DT aliases */
		id = of_alias_get_id(np, "serial");
		if (id >= 0)
			p->line = id;
#ifdef CONFIG_64BIT
		if (of_device_is_compatible(np, "cavium,octeon-3860-uart")) {
			p->serial_in = dw8250_serial_inq;
			p->serial_out = dw8250_serial_outq;
			p->flags = UPF_SKIP_TEST | UPF_SHARE_IRQ | UPF_FIXED_TYPE;
			p->type = PORT_OCTEON;
			data->usr_reg = 0x27;
			data->skip_autocfg = true;
		}
#endif
	} else if (has_acpi_companion(p->dev)) {
		p->iotype = UPIO_MEM32;
		p->regshift = 2;
		p->serial_in = dw8250_serial_in32;
		p->set_termios = dw8250_set_termios;
		/* So far none of there implement the Busy Functionality */
		data->uart_16550_compatible = true;
	}

	/* Platforms with iDMA */
	if (platform_get_resource_byname(to_platform_device(p->dev),
					 IORESOURCE_MEM, "lpss_priv")) {
		p->set_termios = dw8250_set_termios;
		data->dma.rx_param = p->dev->parent;
		data->dma.tx_param = p->dev->parent;
		data->dma.fn = dw8250_idma_filter;
	}
}

static void dw8250_setup_port(struct uart_port *p)
{
	struct uart_8250_port *up = up_to_u8250p(p);
	u32 reg;

	/*
	 * If the Component Version Register returns zero, we know that
	 * ADDITIONAL_FEATURES are not enabled. No need to go any further.
	 */
	reg = readl(p->membase + DW_UART_UCV);
	if (!reg)
		return;

	dev_dbg(p->dev, "Designware UART version %c.%c%c\n",
		(reg >> 24) & 0xff, (reg >> 16) & 0xff, (reg >> 8) & 0xff);

	reg = readl(p->membase + DW_UART_CPR);
	if (!reg)
		return;

	/* Select the type based on fifo */
	if (reg & DW_UART_CPR_FIFO_MODE) {
		p->type = PORT_16550A;
		p->flags |= UPF_FIXED_TYPE;
		p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
		up->capabilities = UART_CAP_FIFO;
	}

	if (reg & DW_UART_CPR_AFCE_MODE)
		up->capabilities |= UART_CAP_AFE;
}

static int dw8250_probe(struct platform_device *pdev)
{
	struct uart_8250_port uart = {};
	struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	int irq = platform_get_irq(pdev, 0);
	struct uart_port *p = &uart.port;
	struct dw8250_data *data;
	int err;
	u32 val;

	if (!regs) {
		dev_err(&pdev->dev, "no registers defined\n");
		return -EINVAL;
	}

	if (irq < 0) {
		if (irq != -EPROBE_DEFER)
			dev_err(&pdev->dev, "cannot get irq\n");
		return irq;
	}

	spin_lock_init(&p->lock);
	p->mapbase	= regs->start;
	p->irq		= irq;
	p->handle_irq	= dw8250_handle_irq;
	p->pm		= dw8250_do_pm;
	p->type		= PORT_8250;
	p->flags	= UPF_SHARE_IRQ | UPF_FIXED_PORT;
	p->dev		= &pdev->dev;
	p->iotype	= UPIO_MEM;
	p->serial_in	= dw8250_serial_in;
	p->serial_out	= dw8250_serial_out;

	p->membase = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
	if (!p->membase)
		return -ENOMEM;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->dma.fn = dw8250_fallback_dma_filter;
	data->usr_reg = DW_UART_USR;
	p->private_data = data;

	data->uart_16550_compatible = device_property_read_bool(p->dev,
						"snps,uart-16550-compatible");

	err = device_property_read_u32(p->dev, "reg-shift", &val);
	if (!err)
		p->regshift = val;

	err = device_property_read_u32(p->dev, "reg-io-width", &val);
	if (!err && val == 4) {
		p->iotype = UPIO_MEM32;
		p->serial_in = dw8250_serial_in32;
		p->serial_out = dw8250_serial_out32;
	}

	if (device_property_read_bool(p->dev, "dcd-override")) {
		/* Always report DCD as active */
		data->msr_mask_on |= UART_MSR_DCD;
		data->msr_mask_off |= UART_MSR_DDCD;
	}

	if (device_property_read_bool(p->dev, "dsr-override")) {
		/* Always report DSR as active */
		data->msr_mask_on |= UART_MSR_DSR;
		data->msr_mask_off |= UART_MSR_DDSR;
	}

	if (device_property_read_bool(p->dev, "cts-override")) {
		/* Always report CTS as active */
		data->msr_mask_on |= UART_MSR_CTS;
		data->msr_mask_off |= UART_MSR_DCTS;
	}

	if (device_property_read_bool(p->dev, "ri-override")) {
		/* Always report Ring indicator as inactive */
		data->msr_mask_off |= UART_MSR_RI;
		data->msr_mask_off |= UART_MSR_TERI;
	}

	/* Always ask for fixed clock rate from a property. */
	device_property_read_u32(p->dev, "clock-frequency", &p->uartclk);

	/* If there is separate baudclk, get the rate from it. */
	data->clk = devm_clk_get(&pdev->dev, "baudclk");
	if (IS_ERR(data->clk) && PTR_ERR(data->clk) != -EPROBE_DEFER)
		data->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(data->clk) && PTR_ERR(data->clk) == -EPROBE_DEFER)
		return -EPROBE_DEFER;
	if (!IS_ERR_OR_NULL(data->clk)) {
		err = clk_prepare_enable(data->clk);
		if (err)
			dev_warn(&pdev->dev, "could not enable optional baudclk: %d\n",
				 err);
		else
			p->uartclk = clk_get_rate(data->clk);
	}

	/* If no clock rate is defined, fail. */
	if (!p->uartclk) {
		dev_err(&pdev->dev, "clock rate not defined\n");
		return -EINVAL;
	}

	data->pclk = devm_clk_get(&pdev->dev, "apb_pclk");
	if (IS_ERR(data->clk) && PTR_ERR(data->clk) == -EPROBE_DEFER) {
		err = -EPROBE_DEFER;
		goto err_clk;
	}
	if (!IS_ERR(data->pclk)) {
		err = clk_prepare_enable(data->pclk);
		if (err) {
			dev_err(&pdev->dev, "could not enable apb_pclk\n");
			goto err_clk;
		}
	}

	data->rst = devm_reset_control_get_optional(&pdev->dev, NULL);
	if (IS_ERR(data->rst) && PTR_ERR(data->rst) == -EPROBE_DEFER) {
		err = -EPROBE_DEFER;
		goto err_pclk;
	}
	if (!IS_ERR(data->rst))
		reset_control_deassert(data->rst);

	dw8250_quirks(p, data);

	/* If the Busy Functionality is not implemented, don't handle it */
	if (data->uart_16550_compatible) {
		p->serial_out = NULL;
		p->handle_irq = NULL;
	}

	if (!data->skip_autocfg)
		dw8250_setup_port(p);

	/* If we have a valid fifosize, try hooking up DMA */
	if (p->fifosize) {
		data->dma.rxconf.src_maxburst = p->fifosize / 4;
		data->dma.txconf.dst_maxburst = p->fifosize / 4;
		uart.dma = &data->dma;
	}

	data->line = serial8250_register_8250_port(&uart);
	if (data->line < 0) {
		err = data->line;
		goto err_reset;
	}

	platform_set_drvdata(pdev, data);

	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	return 0;

err_reset:
	if (!IS_ERR(data->rst))
		reset_control_assert(data->rst);

err_pclk:
	if (!IS_ERR(data->pclk))
		clk_disable_unprepare(data->pclk);

err_clk:
	if (!IS_ERR(data->clk))
		clk_disable_unprepare(data->clk);

	return err;
}

static int dw8250_remove(struct platform_device *pdev)
{
	struct dw8250_data *data = platform_get_drvdata(pdev);

	pm_runtime_get_sync(&pdev->dev);

	serial8250_unregister_port(data->line);

	if (!IS_ERR(data->rst))
		reset_control_assert(data->rst);

	if (!IS_ERR(data->pclk))
		clk_disable_unprepare(data->pclk);

	if (!IS_ERR(data->clk))
		clk_disable_unprepare(data->clk);

	pm_runtime_disable(&pdev->dev);
	pm_runtime_put_noidle(&pdev->dev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int dw8250_suspend(struct device *dev)
{
	struct dw8250_data *data = dev_get_drvdata(dev);

	serial8250_suspend_port(data->line);

	return 0;
}

static int dw8250_resume(struct device *dev)
{
	struct dw8250_data *data = dev_get_drvdata(dev);

	serial8250_resume_port(data->line);

	return 0;
}
#endif /* CONFIG_PM_SLEEP */

#ifdef CONFIG_PM
static int dw8250_runtime_suspend(struct device *dev)
{
	struct dw8250_data *data = dev_get_drvdata(dev);

	if (!IS_ERR(data->clk))
		clk_disable_unprepare(data->clk);

	if (!IS_ERR(data->pclk))
		clk_disable_unprepare(data->pclk);

	return 0;
}

static int dw8250_runtime_resume(struct device *dev)
{
	struct dw8250_data *data = dev_get_drvdata(dev);

	if (!IS_ERR(data->pclk))
		clk_prepare_enable(data->pclk);

	if (!IS_ERR(data->clk))
		clk_prepare_enable(data->clk);

	return 0;
}
#endif

static const struct dev_pm_ops dw8250_pm_ops = {
	SET_SYSTEM_SLEEP_PM_OPS(dw8250_suspend, dw8250_resume)
	SET_RUNTIME_PM_OPS(dw8250_runtime_suspend, dw8250_runtime_resume, NULL)
};

static const struct of_device_id dw8250_of_match[] = {
	{ .compatible = "snps,dw-apb-uart" },
	{ .compatible = "cavium,octeon-3860-uart" },
	{ /* Sentinel */ }
};
MODULE_DEVICE_TABLE(of, dw8250_of_match);

static const struct acpi_device_id dw8250_acpi_match[] = {
	{ "INT33C4", 0 },
	{ "INT33C5", 0 },
	{ "INT3434", 0 },
	{ "INT3435", 0 },
	{ "80860F0A", 0 },
	{ "8086228A", 0 },
	{ "APMC0D08", 0},
	{ "AMD0020", 0 },
	{ },
};
MODULE_DEVICE_TABLE(acpi, dw8250_acpi_match);

static struct platform_driver dw8250_platform_driver = {
	.driver = {
		.name		= "dw-apb-uart",
		.pm		= &dw8250_pm_ops,
		.of_match_table	= dw8250_of_match,
		.acpi_match_table = ACPI_PTR(dw8250_acpi_match),
	},
	.probe			= dw8250_probe,
	.remove			= dw8250_remove,
};

module_platform_driver(dw8250_platform_driver);

MODULE_AUTHOR("Jamie Iles");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Synopsys DesignWare 8250 serial port driver");
MODULE_ALIAS("platform:dw-apb-uart");