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sdhci-s3c: add support for the non standard minimal clock value
[net-next-2.6.git] / drivers / mmc / host / sdhci-s3c.c
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1/* linux/drivers/mmc/host/sdhci-s3c.c
2 *
3 * Copyright 2008 Openmoko Inc.
4 * Copyright 2008 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>
6 * http://armlinux.simtec.co.uk/
7 *
8 * SDHCI (HSMMC) support for Samsung SoC
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15#include <linux/delay.h>
16#include <linux/dma-mapping.h>
17#include <linux/platform_device.h>
5a0e3ad6 18#include <linux/slab.h>
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19#include <linux/clk.h>
20#include <linux/io.h>
21
22#include <linux/mmc/host.h>
23
24#include <plat/sdhci.h>
25#include <plat/regs-sdhci.h>
26
27#include "sdhci.h"
28
29#define MAX_BUS_CLK (4)
30
31/**
32 * struct sdhci_s3c - S3C SDHCI instance
33 * @host: The SDHCI host created
34 * @pdev: The platform device we where created from.
35 * @ioarea: The resource created when we claimed the IO area.
36 * @pdata: The platform data for this controller.
37 * @cur_clk: The index of the current bus clock.
38 * @clk_io: The clock for the internal bus interface.
39 * @clk_bus: The clocks that are available for the SD/MMC bus clock.
40 */
41struct sdhci_s3c {
42 struct sdhci_host *host;
43 struct platform_device *pdev;
44 struct resource *ioarea;
45 struct s3c_sdhci_platdata *pdata;
46 unsigned int cur_clk;
47
48 struct clk *clk_io;
49 struct clk *clk_bus[MAX_BUS_CLK];
50};
51
52static inline struct sdhci_s3c *to_s3c(struct sdhci_host *host)
53{
54 return sdhci_priv(host);
55}
56
57/**
58 * get_curclk - convert ctrl2 register to clock source number
59 * @ctrl2: Control2 register value.
60 */
61static u32 get_curclk(u32 ctrl2)
62{
63 ctrl2 &= S3C_SDHCI_CTRL2_SELBASECLK_MASK;
64 ctrl2 >>= S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
65
66 return ctrl2;
67}
68
69static void sdhci_s3c_check_sclk(struct sdhci_host *host)
70{
71 struct sdhci_s3c *ourhost = to_s3c(host);
72 u32 tmp = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
73
74 if (get_curclk(tmp) != ourhost->cur_clk) {
75 dev_dbg(&ourhost->pdev->dev, "restored ctrl2 clock setting\n");
76
77 tmp &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
78 tmp |= ourhost->cur_clk << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
79 writel(tmp, host->ioaddr + 0x80);
80 }
81}
82
83/**
84 * sdhci_s3c_get_max_clk - callback to get maximum clock frequency.
85 * @host: The SDHCI host instance.
86 *
87 * Callback to return the maximum clock rate acheivable by the controller.
88*/
89static unsigned int sdhci_s3c_get_max_clk(struct sdhci_host *host)
90{
91 struct sdhci_s3c *ourhost = to_s3c(host);
92 struct clk *busclk;
93 unsigned int rate, max;
94 int clk;
95
96 /* note, a reset will reset the clock source */
97
98 sdhci_s3c_check_sclk(host);
99
100 for (max = 0, clk = 0; clk < MAX_BUS_CLK; clk++) {
101 busclk = ourhost->clk_bus[clk];
102 if (!busclk)
103 continue;
104
105 rate = clk_get_rate(busclk);
106 if (rate > max)
107 max = rate;
108 }
109
110 return max;
111}
112
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113/**
114 * sdhci_s3c_consider_clock - consider one the bus clocks for current setting
115 * @ourhost: Our SDHCI instance.
116 * @src: The source clock index.
117 * @wanted: The clock frequency wanted.
118 */
119static unsigned int sdhci_s3c_consider_clock(struct sdhci_s3c *ourhost,
120 unsigned int src,
121 unsigned int wanted)
122{
123 unsigned long rate;
124 struct clk *clksrc = ourhost->clk_bus[src];
125 int div;
126
127 if (!clksrc)
128 return UINT_MAX;
129
130 rate = clk_get_rate(clksrc);
131
132 for (div = 1; div < 256; div *= 2) {
133 if ((rate / div) <= wanted)
134 break;
135 }
136
137 dev_dbg(&ourhost->pdev->dev, "clk %d: rate %ld, want %d, got %ld\n",
138 src, rate, wanted, rate / div);
139
140 return (wanted - (rate / div));
141}
142
143/**
144 * sdhci_s3c_set_clock - callback on clock change
145 * @host: The SDHCI host being changed
146 * @clock: The clock rate being requested.
147 *
148 * When the card's clock is going to be changed, look at the new frequency
149 * and find the best clock source to go with it.
150*/
151static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock)
152{
153 struct sdhci_s3c *ourhost = to_s3c(host);
154 unsigned int best = UINT_MAX;
155 unsigned int delta;
156 int best_src = 0;
157 int src;
158 u32 ctrl;
159
160 /* don't bother if the clock is going off. */
161 if (clock == 0)
162 return;
163
164 for (src = 0; src < MAX_BUS_CLK; src++) {
165 delta = sdhci_s3c_consider_clock(ourhost, src, clock);
166 if (delta < best) {
167 best = delta;
168 best_src = src;
169 }
170 }
171
172 dev_dbg(&ourhost->pdev->dev,
173 "selected source %d, clock %d, delta %d\n",
174 best_src, clock, best);
175
176 /* select the new clock source */
177
178 if (ourhost->cur_clk != best_src) {
179 struct clk *clk = ourhost->clk_bus[best_src];
180
181 /* turn clock off to card before changing clock source */
182 writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);
183
184 ourhost->cur_clk = best_src;
185 host->max_clk = clk_get_rate(clk);
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186
187 ctrl = readl(host->ioaddr + S3C_SDHCI_CONTROL2);
188 ctrl &= ~S3C_SDHCI_CTRL2_SELBASECLK_MASK;
189 ctrl |= best_src << S3C_SDHCI_CTRL2_SELBASECLK_SHIFT;
190 writel(ctrl, host->ioaddr + S3C_SDHCI_CONTROL2);
191 }
192
193 /* reconfigure the hardware for new clock rate */
194
195 {
196 struct mmc_ios ios;
197
198 ios.clock = clock;
199
200 if (ourhost->pdata->cfg_card)
201 (ourhost->pdata->cfg_card)(ourhost->pdev, host->ioaddr,
202 &ios, NULL);
203 }
204}
205
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206/**
207 * sdhci_s3c_get_min_clock - callback to get minimal supported clock value
208 * @host: The SDHCI host being queried
209 *
210 * To init mmc host properly a minimal clock value is needed. For high system
211 * bus clock's values the standard formula gives values out of allowed range.
212 * The clock still can be set to lower values, if clock source other then
213 * system bus is selected.
214*/
215static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host)
216{
217 struct sdhci_s3c *ourhost = to_s3c(host);
218 unsigned int delta, min = UINT_MAX;
219 int src;
220
221 for (src = 0; src < MAX_BUS_CLK; src++) {
222 delta = sdhci_s3c_consider_clock(ourhost, src, 0);
223 if (delta == UINT_MAX)
224 continue;
225 /* delta is a negative value in this case */
226 if (-delta < min)
227 min = -delta;
228 }
229 return min;
230}
231
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232static struct sdhci_ops sdhci_s3c_ops = {
233 .get_max_clock = sdhci_s3c_get_max_clk,
0d1bb41a 234 .set_clock = sdhci_s3c_set_clock,
ce5f036b 235 .get_min_clock = sdhci_s3c_get_min_clock,
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236};
237
238static int __devinit sdhci_s3c_probe(struct platform_device *pdev)
239{
240 struct s3c_sdhci_platdata *pdata = pdev->dev.platform_data;
241 struct device *dev = &pdev->dev;
242 struct sdhci_host *host;
243 struct sdhci_s3c *sc;
244 struct resource *res;
245 int ret, irq, ptr, clks;
246
247 if (!pdata) {
248 dev_err(dev, "no device data specified\n");
249 return -ENOENT;
250 }
251
252 irq = platform_get_irq(pdev, 0);
253 if (irq < 0) {
254 dev_err(dev, "no irq specified\n");
255 return irq;
256 }
257
258 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
259 if (!res) {
260 dev_err(dev, "no memory specified\n");
261 return -ENOENT;
262 }
263
264 host = sdhci_alloc_host(dev, sizeof(struct sdhci_s3c));
265 if (IS_ERR(host)) {
266 dev_err(dev, "sdhci_alloc_host() failed\n");
267 return PTR_ERR(host);
268 }
269
270 sc = sdhci_priv(host);
271
272 sc->host = host;
273 sc->pdev = pdev;
274 sc->pdata = pdata;
275
276 platform_set_drvdata(pdev, host);
277
278 sc->clk_io = clk_get(dev, "hsmmc");
279 if (IS_ERR(sc->clk_io)) {
280 dev_err(dev, "failed to get io clock\n");
281 ret = PTR_ERR(sc->clk_io);
282 goto err_io_clk;
283 }
284
285 /* enable the local io clock and keep it running for the moment. */
286 clk_enable(sc->clk_io);
287
288 for (clks = 0, ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
289 struct clk *clk;
290 char *name = pdata->clocks[ptr];
291
292 if (name == NULL)
293 continue;
294
295 clk = clk_get(dev, name);
296 if (IS_ERR(clk)) {
297 dev_err(dev, "failed to get clock %s\n", name);
298 continue;
299 }
300
301 clks++;
302 sc->clk_bus[ptr] = clk;
303 clk_enable(clk);
304
305 dev_info(dev, "clock source %d: %s (%ld Hz)\n",
306 ptr, name, clk_get_rate(clk));
307 }
308
309 if (clks == 0) {
310 dev_err(dev, "failed to find any bus clocks\n");
311 ret = -ENOENT;
312 goto err_no_busclks;
313 }
314
315 sc->ioarea = request_mem_region(res->start, resource_size(res),
316 mmc_hostname(host->mmc));
317 if (!sc->ioarea) {
318 dev_err(dev, "failed to reserve register area\n");
319 ret = -ENXIO;
320 goto err_req_regs;
321 }
322
323 host->ioaddr = ioremap_nocache(res->start, resource_size(res));
324 if (!host->ioaddr) {
325 dev_err(dev, "failed to map registers\n");
326 ret = -ENXIO;
327 goto err_req_regs;
328 }
329
330 /* Ensure we have minimal gpio selected CMD/CLK/Detect */
331 if (pdata->cfg_gpio)
332 pdata->cfg_gpio(pdev, pdata->max_width);
333
334 host->hw_name = "samsung-hsmmc";
335 host->ops = &sdhci_s3c_ops;
336 host->quirks = 0;
337 host->irq = irq;
338
339 /* Setup quirks for the controller */
b2e75eff 340 host->quirks |= SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC;
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341
342#ifndef CONFIG_MMC_SDHCI_S3C_DMA
343
344 /* we currently see overruns on errors, so disable the SDMA
345 * support as well. */
346 host->quirks |= SDHCI_QUIRK_BROKEN_DMA;
347
348#endif /* CONFIG_MMC_SDHCI_S3C_DMA */
349
350 /* It seems we do not get an DATA transfer complete on non-busy
351 * transfers, not sure if this is a problem with this specific
352 * SDHCI block, or a missing configuration that needs to be set. */
353 host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ;
354
355 host->quirks |= (SDHCI_QUIRK_32BIT_DMA_ADDR |
356 SDHCI_QUIRK_32BIT_DMA_SIZE);
357
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358 /* HSMMC on Samsung SoCs uses SDCLK as timeout clock */
359 host->quirks |= SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK;
360
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361 ret = sdhci_add_host(host);
362 if (ret) {
363 dev_err(dev, "sdhci_add_host() failed\n");
364 goto err_add_host;
365 }
366
367 return 0;
368
369 err_add_host:
370 release_resource(sc->ioarea);
371 kfree(sc->ioarea);
372
373 err_req_regs:
374 for (ptr = 0; ptr < MAX_BUS_CLK; ptr++) {
375 clk_disable(sc->clk_bus[ptr]);
376 clk_put(sc->clk_bus[ptr]);
377 }
378
379 err_no_busclks:
380 clk_disable(sc->clk_io);
381 clk_put(sc->clk_io);
382
383 err_io_clk:
384 sdhci_free_host(host);
385
386 return ret;
387}
388
389static int __devexit sdhci_s3c_remove(struct platform_device *pdev)
390{
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391 struct sdhci_host *host = platform_get_drvdata(pdev);
392 struct sdhci_s3c *sc = sdhci_priv(host);
393 int ptr;
394
395 sdhci_remove_host(host, 1);
396
397 for (ptr = 0; ptr < 3; ptr++) {
398 clk_disable(sc->clk_bus[ptr]);
399 clk_put(sc->clk_bus[ptr]);
400 }
401 clk_disable(sc->clk_io);
402 clk_put(sc->clk_io);
403
404 iounmap(host->ioaddr);
405 release_resource(sc->ioarea);
406 kfree(sc->ioarea);
407
408 sdhci_free_host(host);
409 platform_set_drvdata(pdev, NULL);
410
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411 return 0;
412}
413
414#ifdef CONFIG_PM
415
416static int sdhci_s3c_suspend(struct platform_device *dev, pm_message_t pm)
417{
418 struct sdhci_host *host = platform_get_drvdata(dev);
419
420 sdhci_suspend_host(host, pm);
421 return 0;
422}
423
424static int sdhci_s3c_resume(struct platform_device *dev)
425{
426 struct sdhci_host *host = platform_get_drvdata(dev);
427
428 sdhci_resume_host(host);
429 return 0;
430}
431
432#else
433#define sdhci_s3c_suspend NULL
434#define sdhci_s3c_resume NULL
435#endif
436
437static struct platform_driver sdhci_s3c_driver = {
438 .probe = sdhci_s3c_probe,
439 .remove = __devexit_p(sdhci_s3c_remove),
440 .suspend = sdhci_s3c_suspend,
441 .resume = sdhci_s3c_resume,
442 .driver = {
443 .owner = THIS_MODULE,
444 .name = "s3c-sdhci",
445 },
446};
447
448static int __init sdhci_s3c_init(void)
449{
450 return platform_driver_register(&sdhci_s3c_driver);
451}
452
453static void __exit sdhci_s3c_exit(void)
454{
455 platform_driver_unregister(&sdhci_s3c_driver);
456}
457
458module_init(sdhci_s3c_init);
459module_exit(sdhci_s3c_exit);
460
461MODULE_DESCRIPTION("Samsung SDHCI (HSMMC) glue");
462MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
463MODULE_LICENSE("GPL v2");
464MODULE_ALIAS("platform:s3c-sdhci");