aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/mmc/host/sdhci-s3c.c
blob: ad3a78edeb8a9ad4907efe50e2c0d641c0f0903b (plain) (blame)
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
/* linux/drivers/mmc/host/sdhci-s3c.c
 *
 * Copyright 2008 Openmoko Inc.
 * Copyright 2008 Simtec Electronics
 *      Ben Dooks <ben@simtec.co.uk>
 *      http://armlinux.simtec.co.uk/
 *
 * SDHCI (HSMMC) support for Samsung SoC
 *
 * 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.
 */

#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/io.h>

#include <linux/mmc/host.h>

#include <plat/sdhci.h>
#include <plat/regs-sdhci.h>

#include "sdhci.h"

#define MAX_BUS_CLK	(4)

/**
 * struct sdhci_s3c - S3C SDHCI instance
 * @host: The SDHCI host created
 * @pdev: The platform device we where created from.
 * @ioarea: The resource created when we claimed the IO area.
 * @pdata: The platform data for this controller.
 * @cur_clk: The index of the current bus clock.
 * @clk_io: The clock for the internal bus interface.
 * @clk_bus: The clocks that are available for the SD/MMC bus clock.
 */
struct sdhci_s3c {
	struct sdhci_host	*host;
	struct platform_device	*pdev;
	struct resource		*ioarea;
	struct s3c_sdhci_platdata *pdata;
	unsigned int		cur_clk;

	struct clk		*clk_io;
	struct clk		*clk_bus[MAX_BUS_CLK];
};

static inline struct sdhci_s3c *to_s3c(struct sdhci_host *host)
{
	return sdhci_priv(host);
}

/**
 * get_curclk - convert ctrl2 register to clock source number
 * @ctrl2: Control2 register value.
 */
static u32 get_curclk(u32 ctrl2)
{
	ctrl2 &= S3C_SDHCI_CTRL2_SELBASECLK_MASK;
	ctrl2 >>= S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;

	return ctrl2;
}

static void sdhci_s3c_check_sclk(struct sdhci_host *host)
{
	struct sdhci_s3c *ourhost = to_s3c(host);
	u32 tmp = readl(host->ioaddr + S3C_SDHCI_CONTROL2);

	if (get_curclk(tmp) != ourhost->cur_clk) {
		dev_dbg(&ourhost->pdev->dev, "restored ctrl2 clock setting\n");

		tmp &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
		tmp |= ourhost->cur_clk << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
		writel(tmp, host->ioaddr + 0x80);
	}
}

/**
 * sdhci_s3c_get_max_clk - callback to get maximum clock frequency.
 * @host: The SDHCI host instance.
 *
 * Callback to return the maximum clock rate acheivable by the controller.
*/
static unsigned int sdhci_s3c_get_max_clk(struct sdhci_host *host)
{
	struct sdhci_s3c *ourhost = to_s3c(host);
	struct clk *busclk;
	unsigned int rate, max;
	int clk;

	/* note, a reset will reset the clock source */

	sdhci_s3c_check_sclk(host);

	for (max = 0, clk = 0; clk < MAX_BUS_CLK; clk++) {
		busclk = ourhost->clk_bus[clk];
		if (!busclk)
			continue;

		rate = clk_get_rate(busclk);
		if (rate > max)
			max = rate;
	}

	return max;
}

static unsigned int sdhci_s3c_get_timeout_clk(struct sdhci_host *host)
{
	return sdhci_s3c_get_max_clk(host) / 1000000;
}

/**
 * sdhci_s3c_consider_clock - consider one the bus clocks for current setting
 * @ourhost: Our SDHCI instance.
 * @src: The source clock index.
 * @wanted: The clock frequency wanted.
 */
static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
					     unsigned int src,
					     unsigned int wanted)
{
	unsigned long rate;
	struct clk *clksrc = ourhost->clk_bus[src];
	int div;

	if (!clksrc)
		return UINT_MAX;

	rate = clk_get_rate(clksrc);

	for (div = 1; div < 256; div *= 2) {
		if ((rate / div) <= wanted)
			break;
	}

	dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
		src, rate, wanted, rate / div);

	return (wanted - (rate / div));
}

/**
 * sdhci_s3c_set_clock - callback on clock change
 * @host: The SDHCI host being changed
 * @clock: The clock rate being requested.
 *
 * When the card's clock is going to be changed, look at the new frequency
 * and find the best clock source to go with it.
*/
static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock)
{
	struct sdhci_s3c *ourhost = to_s3c(host);
	unsigned int best = UINT_MAX;
	unsigned int delta;
	int best_src = 0;
	int src;
	u32 ctrl;

	/* don't bother if the clock is going off. */
	if (clock == 0)
		return;

	for (src = 0; src < MAX_BUS_CLK; src++) {
		delta = sdhci_s3c_consider_clock(ourhost, src, clock);
		if (delta < best) {
			best = delta;
			best_src = src;
		}
	}

	dev_dbg(&ourhost->pdev->dev,
		"selected source %d, clock %d, delta %d\n",
		 best_src, clock, best);

	/* select the new clock source */

	if (ourhost->cur_clk != best_src) {
		struct clk *clk = ourhost->clk_bus[best_src];

		/* turn clock off to card before changing clock source */
		writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);

		ourhost->cur_clk = best_src;
		host->max_clk = clk_get_rate(clk);
		host->timeout_clk = sdhci_s3c_get_timeout_clk(host);

		ctrl = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
		ctrl &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
		ctrl |= best_src << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
		writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL2);
	}

	/* reconfigure the hardware for new clock rate */

	{
		struct mmc_ios ios;

		ios.clock = clock;

		if (ourhost->pdata->cfg_card)
			(ourhost->pdata->cfg_card)(ourhost->pdev, host->ioaddr,
						   &ios, NULL);
	}
}

static struct sdhci_ops sdhci_s3c_ops = {
	.get_max_clock		= sdhci_s3c_get_max_clk,
	.get_timeout_clock	= sdhci_s3c_get_timeout_clk,
	.set_clock		= sdhci_s3c_set_clock,
};

static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
{
	struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
	struct device *dev = &pdev->dev;
	struct sdhci_host *host;
	struct sdhci_s3c *sc;
	struct resource *res;
	int ret, irq, ptr, clks;

	if (!pdata) {
		dev_err(dev, "no device data specified\n");
		return -ENOENT;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_err(dev, "no irq specified\n");
		return irq;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "no memory specified\n");
		return -ENOENT;
	}

	host = sdhci_alloc_host(dev, sizeof(struct sdhci_s3c));
	if (IS_ERR(host)) {
		dev_err(dev, "sdhci_alloc_host() failed\n");
		return PTR_ERR(host);
	}

	sc = sdhci_priv(host);

	sc->host = host;
	sc->pdev = pdev;
	sc->pdata = pdata;

	platform_set_drvdata(pdev, host);

	sc->clk_io = clk_get(dev, "hsmmc");
	if (IS_ERR(sc->clk_io)) {
		dev_err(dev, "failed to get io clock\n");
		ret = PTR_ERR(sc->clk_io);
		goto err_io_clk;
	}

	/* enable the local io clock and keep it running for the moment. */
	clk_enable(sc->clk_io);

	for (clks = 0, ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
		struct clk *clk;
		char *name = pdata->clocks[ptr];

		if (name == NULL)
			continue;

		clk = clk_get(dev, name);
		if (IS_ERR(clk)) {
			dev_err(dev, "failed to get clock %s\n", name);
			continue;
		}

		clks++;
		sc->clk_bus[ptr] = clk;
		clk_enable(clk);

		dev_info(dev, "clock source %d: %s (%ld Hz)\n",
			 ptr, name, clk_get_rate(clk));
	}

	if (clks == 0) {
		dev_err(dev, "failed to find any bus clocks\n");
		ret = -ENOENT;
		goto err_no_busclks;
	}

	sc->ioarea = request_mem_region(res->start, resource_size(res),
					mmc_hostname(host->mmc));
	if (!sc->ioarea) {
		dev_err(dev, "failed to reserve register area\n");
		ret = -ENXIO;
		goto err_req_regs;
	}

	host->ioaddr = ioremap_nocache(res->start, resource_size(res));
	if (!host->ioaddr) {
		dev_err(dev, "failed to map registers\n");
		ret = -ENXIO;
		goto err_req_regs;
	}

	/* Ensure we have minimal gpio selected CMD/CLK/Detect */
	if (pdata->cfg_gpio)
		pdata->cfg_gpio(pdev, pdata->max_width);

	host->hw_name = "samsung-hsmmc";
	host->ops = &sdhci_s3c_ops;
	host->quirks = 0;
	host->irq = irq;

	/* Setup quirks for the controller */
	host->quirks |= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC;

#ifndef CONFIG_MMC_SDHCI_S3C_DMA

	/* we currently see overruns on errors, so disable the SDMA
	 * support as well. */
	host->quirks |= SDHCI_QUIRK_BROKEN_DMA;

	/* PIO currently has problems with multi-block IO */
	host->quirks |= SDHCI_QUIRK_NO_MULTIBLOCK;

#endif /* CONFIG_MMC_SDHCI_S3C_DMA */

	/* It seems we do not get an DATA transfer complete on non-busy
	 * transfers, not sure if this is a problem with this specific
	 * SDHCI block, or a missing configuration that needs to be set. */
	host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ;

	host->quirks |= (SDHCI_QUIRK_32BIT_DMA_ADDR |
			 SDHCI_QUIRK_32BIT_DMA_SIZE);

	ret = sdhci_add_host(host);
	if (ret) {
		dev_err(dev, "sdhci_add_host() failed\n");
		goto err_add_host;
	}

	return 0;

 err_add_host:
	release_resource(sc->ioarea);
	kfree(sc->ioarea);

 err_req_regs:
	for (ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
		clk_disable(sc->clk_bus[ptr]);
		clk_put(sc->clk_bus[ptr]);
	}

 err_no_busclks:
	clk_disable(sc->clk_io);
	clk_put(sc->clk_io);

 err_io_clk:
	sdhci_free_host(host);

	return ret;
}

static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
{
	return 0;
}

#ifdef CONFIG_PM

static int sdhci_s3c_suspend(struct platform_device *dev, pm_message_t pm)
{
	struct sdhci_host *host = platform_get_drvdata(dev);

	sdhci_suspend_host(host, pm);
	return 0;
}

static int sdhci_s3c_resume(struct platform_device *dev)
{
	struct sdhci_host *host = platform_get_drvdata(dev);

	sdhci_resume_host(host);
	return 0;
}

#else
#define sdhci_s3c_suspend NULL
#define sdhci_s3c_resume NULL
#endif

static struct platform_driver sdhci_s3c_driver = {
	.probe		= sdhci_s3c_probe,
	.remove		= __devexit_p(sdhci_s3c_remove),
	.suspend	= sdhci_s3c_suspend,
	.resume	        = sdhci_s3c_resume,
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "s3c-sdhci",
	},
};

static int __init sdhci_s3c_init(void)
{
	return platform_driver_register(&sdhci_s3c_driver);
}

static void __exit sdhci_s3c_exit(void)
{
	platform_driver_unregister(&sdhci_s3c_driver);
}

module_init(sdhci_s3c_init);
module_exit(sdhci_s3c_exit);

MODULE_DESCRIPTION("Samsung SDHCI (HSMMC) glue");
MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:s3c-sdhci");