summaryrefslogtreecommitdiff
path: root/arch/arm/mach-pxa/ssp.c
blob: 9ebe658590fa5583ac817aa4dce552f709ebbbab (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
/*
 *  linux/arch/arm/mach-pxa/ssp.c
 *
 *  based on linux/arch/arm/mach-sa1100/ssp.c by Russell King
 *
 *  Copyright (C) 2003 Russell King.
 *  Copyright (C) 2003 Wolfson Microelectronics PLC
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 *  PXA2xx SSP driver.  This provides the generic core for simple
 *  IO-based SSP applications and allows easy port setup for DMA access.
 *
 *  Author: Liam Girdwood <liam.girdwood@wolfsonmicro.com>
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <mach/hardware.h>
#include <mach/ssp.h>
#include <mach/regs-ssp.h>

#define TIMEOUT 100000

static irqreturn_t ssp_interrupt(int irq, void *dev_id)
{
	struct ssp_dev *dev = dev_id;
	struct ssp_device *ssp = dev->ssp;
	unsigned int status;

	status = __raw_readl(ssp->mmio_base + SSSR);
	__raw_writel(status, ssp->mmio_base + SSSR);

	if (status & SSSR_ROR)
		printk(KERN_WARNING "SSP(%d): receiver overrun\n", dev->port);

	if (status & SSSR_TUR)
		printk(KERN_WARNING "SSP(%d): transmitter underrun\n", dev->port);

	if (status & SSSR_BCE)
		printk(KERN_WARNING "SSP(%d): bit count error\n", dev->port);

	return IRQ_HANDLED;
}

/**
 * ssp_write_word - write a word to the SSP port
 * @data: 32-bit, MSB justified data to write.
 *
 * Wait for a free entry in the SSP transmit FIFO, and write a data
 * word to the SSP port.
 *
 * The caller is expected to perform the necessary locking.
 *
 * Returns:
 *   %-ETIMEDOUT	timeout occurred
 *   0			success
 */
int ssp_write_word(struct ssp_dev *dev, u32 data)
{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT;

	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_TNF)) {
	        if (!--timeout)
	        	return -ETIMEDOUT;
		cpu_relax();
	}

	__raw_writel(data, ssp->mmio_base + SSDR);

	return 0;
}

/**
 * ssp_read_word - read a word from the SSP port
 *
 * Wait for a data word in the SSP receive FIFO, and return the
 * received data.  Data is LSB justified.
 *
 * Note: Currently, if data is not expected to be received, this
 * function will wait for ever.
 *
 * The caller is expected to perform the necessary locking.
 *
 * Returns:
 *   %-ETIMEDOUT	timeout occurred
 *   32-bit data	success
 */
int ssp_read_word(struct ssp_dev *dev, u32 *data)
{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT;

	while (!(__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE)) {
	        if (!--timeout)
	        	return -ETIMEDOUT;
		cpu_relax();
	}

	*data = __raw_readl(ssp->mmio_base + SSDR);
	return 0;
}

/**
 * ssp_flush - flush the transmit and receive FIFOs
 *
 * Wait for the SSP to idle, and ensure that the receive FIFO
 * is empty.
 *
 * The caller is expected to perform the necessary locking.
 */
int ssp_flush(struct ssp_dev *dev)
{
	struct ssp_device *ssp = dev->ssp;
	int timeout = TIMEOUT * 2;

	/* ensure TX FIFO is empty instead of not full */
	if (cpu_is_pxa3xx()) {
		while (__raw_readl(ssp->mmio_base + SSSR) & 0xf00) {
			if (!--timeout)
				return -ETIMEDOUT;
			cpu_relax();
		}
		timeout = TIMEOUT * 2;
	}

	do {
		while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_RNE) {
		        if (!--timeout)
		        	return -ETIMEDOUT;
			(void)__raw_readl(ssp->mmio_base + SSDR);
		}
	        if (!--timeout)
	        	return -ETIMEDOUT;
	} while (__raw_readl(ssp->mmio_base + SSSR) & SSSR_BSY);

	return 0;
}

/**
 * ssp_enable - enable the SSP port
 *
 * Turn on the SSP port.
 */
void ssp_enable(struct ssp_dev *dev)
{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sscr0;

	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
	sscr0 |= SSCR0_SSE;
	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
}

/**
 * ssp_disable - shut down the SSP port
 *
 * Turn off the SSP port, optionally powering it down.
 */
void ssp_disable(struct ssp_dev *dev)
{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sscr0;

	sscr0 = __raw_readl(ssp->mmio_base + SSCR0);
	sscr0 &= ~SSCR0_SSE;
	__raw_writel(sscr0, ssp->mmio_base + SSCR0);
}

/**
 * ssp_save_state - save the SSP configuration
 * @ssp: pointer to structure to save SSP configuration
 *
 * Save the configured SSP state for suspend.
 */
void ssp_save_state(struct ssp_dev *dev, struct ssp_state *state)
{
	struct ssp_device *ssp = dev->ssp;

	state->cr0 = __raw_readl(ssp->mmio_base + SSCR0);
	state->cr1 = __raw_readl(ssp->mmio_base + SSCR1);
	state->to  = __raw_readl(ssp->mmio_base + SSTO);
	state->psp = __raw_readl(ssp->mmio_base + SSPSP);

	ssp_disable(dev);
}

/**
 * ssp_restore_state - restore a previously saved SSP configuration
 * @ssp: pointer to configuration saved by ssp_save_state
 *
 * Restore the SSP configuration saved previously by ssp_save_state.
 */
void ssp_restore_state(struct ssp_dev *dev, struct ssp_state *state)
{
	struct ssp_device *ssp = dev->ssp;
	uint32_t sssr = SSSR_ROR | SSSR_TUR | SSSR_BCE;

	__raw_writel(sssr, ssp->mmio_base + SSSR);

	__raw_writel(state->cr0 & ~SSCR0_SSE, ssp->mmio_base + SSCR0);
	__raw_writel(state->cr1, ssp->mmio_base + SSCR1);
	__raw_writel(state->to,  ssp->mmio_base + SSTO);
	__raw_writel(state->psp, ssp->mmio_base + SSPSP);
	__raw_writel(state->cr0, ssp->mmio_base + SSCR0);
}

/**
 * ssp_config - configure SSP port settings
 * @mode: port operating mode
 * @flags: port config flags
 * @psp_flags: port PSP config flags
 * @speed: port speed
 *
 * Port MUST be disabled by ssp_disable before making any config changes.
 */
int ssp_config(struct ssp_dev *dev, u32 mode, u32 flags, u32 psp_flags, u32 speed)
{
	struct ssp_device *ssp = dev->ssp;

	dev->mode = mode;
	dev->flags = flags;
	dev->psp_flags = psp_flags;
	dev->speed = speed;

	/* set up port type, speed, port settings */
	__raw_writel((dev->speed | dev->mode), ssp->mmio_base + SSCR0);
	__raw_writel(dev->flags, ssp->mmio_base + SSCR1);
	__raw_writel(dev->psp_flags, ssp->mmio_base + SSPSP);

	return 0;
}

/**
 * ssp_init - setup the SSP port
 *
 * initialise and claim resources for the SSP port.
 *
 * Returns:
 *   %-ENODEV	if the SSP port is unavailable
 *   %-EBUSY	if the resources are already in use
 *   %0		on success
 */
int ssp_init(struct ssp_dev *dev, u32 port, u32 init_flags)
{
	struct ssp_device *ssp;
	int ret;

	ssp = ssp_request(port, "SSP");
	if (ssp == NULL)
		return -ENODEV;

	dev->ssp = ssp;
	dev->port = port;

	/* do we need to get irq */
	if (!(init_flags & SSP_NO_IRQ)) {
		ret = request_irq(ssp->irq, ssp_interrupt,
				0, "SSP", dev);
	    	if (ret)
			goto out_region;
		dev->irq = ssp->irq;
	} else
		dev->irq = NO_IRQ;

	/* turn on SSP port clock */
	clk_enable(ssp->clk);
	return 0;

out_region:
	ssp_free(ssp);
	return ret;
}

/**
 * ssp_exit - undo the effects of ssp_init
 *
 * release and free resources for the SSP port.
 */
void ssp_exit(struct ssp_dev *dev)
{
	struct ssp_device *ssp = dev->ssp;

	ssp_disable(dev);
	if (dev->irq != NO_IRQ)
		free_irq(dev->irq, dev);
	clk_disable(ssp->clk);
	ssp_free(ssp);
}

static DEFINE_MUTEX(ssp_lock);
static LIST_HEAD(ssp_list);

struct ssp_device *ssp_request(int port, const char *label)
{
	struct ssp_device *ssp = NULL;

	mutex_lock(&ssp_lock);

	list_for_each_entry(ssp, &ssp_list, node) {
		if (ssp->port_id == port && ssp->use_count == 0) {
			ssp->use_count++;
			ssp->label = label;
			break;
		}
	}

	mutex_unlock(&ssp_lock);

	if (&ssp->node == &ssp_list)
		return NULL;

	return ssp;
}
EXPORT_SYMBOL(ssp_request);

void ssp_free(struct ssp_device *ssp)
{
	mutex_lock(&ssp_lock);
	if (ssp->use_count) {
		ssp->use_count--;
		ssp->label = NULL;
	} else
		dev_err(&ssp->pdev->dev, "device already free\n");
	mutex_unlock(&ssp_lock);
}
EXPORT_SYMBOL(ssp_free);

static int __devinit ssp_probe(struct platform_device *pdev)
{
	const struct platform_device_id *id = platform_get_device_id(pdev);
	struct resource *res;
	struct ssp_device *ssp;
	int ret = 0;

	ssp = kzalloc(sizeof(struct ssp_device), GFP_KERNEL);
	if (ssp == NULL) {
		dev_err(&pdev->dev, "failed to allocate memory");
		return -ENOMEM;
	}
	ssp->pdev = pdev;

	ssp->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(ssp->clk)) {
		ret = PTR_ERR(ssp->clk);
		goto err_free;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (res == NULL) {
		dev_err(&pdev->dev, "no memory resource defined\n");
		ret = -ENODEV;
		goto err_free_clk;
	}

	res = request_mem_region(res->start, res->end - res->start + 1,
			pdev->name);
	if (res == NULL) {
		dev_err(&pdev->dev, "failed to request memory resource\n");
		ret = -EBUSY;
		goto err_free_clk;
	}

	ssp->phys_base = res->start;

	ssp->mmio_base = ioremap(res->start, res->end - res->start + 1);
	if (ssp->mmio_base == NULL) {
		dev_err(&pdev->dev, "failed to ioremap() registers\n");
		ret = -ENODEV;
		goto err_free_mem;
	}

	ssp->irq = platform_get_irq(pdev, 0);
	if (ssp->irq < 0) {
		dev_err(&pdev->dev, "no IRQ resource defined\n");
		ret = -ENODEV;
		goto err_free_io;
	}

	res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (res == NULL) {
		dev_err(&pdev->dev, "no SSP RX DRCMR defined\n");
		ret = -ENODEV;
		goto err_free_io;
	}
	ssp->drcmr_rx = res->start;

	res = platform_get_resource(pdev, IORESOURCE_DMA, 1);
	if (res == NULL) {
		dev_err(&pdev->dev, "no SSP TX DRCMR defined\n");
		ret = -ENODEV;
		goto err_free_io;
	}
	ssp->drcmr_tx = res->start;

	/* PXA2xx/3xx SSP ports starts from 1 and the internal pdev->id
	 * starts from 0, do a translation here
	 */
	ssp->port_id = pdev->id + 1;
	ssp->use_count = 0;
	ssp->type = (int)id->driver_data;

	mutex_lock(&ssp_lock);
	list_add(&ssp->node, &ssp_list);
	mutex_unlock(&ssp_lock);

	platform_set_drvdata(pdev, ssp);
	return 0;

err_free_io:
	iounmap(ssp->mmio_base);
err_free_mem:
	release_mem_region(res->start, res->end - res->start + 1);
err_free_clk:
	clk_put(ssp->clk);
err_free:
	kfree(ssp);
	return ret;
}

static int __devexit ssp_remove(struct platform_device *pdev)
{
	struct resource *res;
	struct ssp_device *ssp;

	ssp = platform_get_drvdata(pdev);
	if (ssp == NULL)
		return -ENODEV;

	iounmap(ssp->mmio_base);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	release_mem_region(res->start, res->end - res->start + 1);

	clk_put(ssp->clk);

	mutex_lock(&ssp_lock);
	list_del(&ssp->node);
	mutex_unlock(&ssp_lock);

	kfree(ssp);
	return 0;
}

static const struct platform_device_id ssp_id_table[] = {
	{ "pxa25x-ssp",		PXA25x_SSP },
	{ "pxa25x-nssp",	PXA25x_NSSP },
	{ "pxa27x-ssp",		PXA27x_SSP },
	{ },
};

static struct platform_driver ssp_driver = {
	.probe		= ssp_probe,
	.remove		= __devexit_p(ssp_remove),
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "pxa2xx-ssp",
	},
	.id_table	= ssp_id_table,
};

static int __init pxa_ssp_init(void)
{
	return platform_driver_register(&ssp_driver);
}

static void __exit pxa_ssp_exit(void)
{
	platform_driver_unregister(&ssp_driver);
}

arch_initcall(pxa_ssp_init);
module_exit(pxa_ssp_exit);

EXPORT_SYMBOL(ssp_write_word);
EXPORT_SYMBOL(ssp_read_word);
EXPORT_SYMBOL(ssp_flush);
EXPORT_SYMBOL(ssp_enable);
EXPORT_SYMBOL(ssp_disable);
EXPORT_SYMBOL(ssp_save_state);
EXPORT_SYMBOL(ssp_restore_state);
EXPORT_SYMBOL(ssp_init);
EXPORT_SYMBOL(ssp_exit);
EXPORT_SYMBOL(ssp_config);

MODULE_DESCRIPTION("PXA SSP driver");
MODULE_AUTHOR("Liam Girdwood");
MODULE_LICENSE("GPL");