1 /*
2  * Atmel SAMA5D2-Compatible Shutdown Controller (SHDWC) driver.
3  * Found on some SoCs as the sama5d2 (obviously).
4  *
5  * Copyright (C) 2015 Atmel Corporation,
6  *                    Nicolas Ferre <nicolas.ferre@atmel.com>
7  *
8  * Evolved from driver at91-poweroff.c.
9  *
10  * This file is licensed under the terms of the GNU General Public
11  * License version 2.  This program is licensed "as is" without any
12  * warranty of any kind, whether express or implied.
13  *
14  * TODO:
15  * - addition to status of other wake-up inputs [1 - 15]
16  * - Analog Comparator wake-up alarm
17  * - Serial RX wake-up alarm
18  * - low power debouncer
19  */
20 
21 #include <linux/clk.h>
22 #include <linux/clk/at91_pmc.h>
23 #include <linux/io.h>
24 #include <linux/module.h>
25 #include <linux/of.h>
26 #include <linux/of_address.h>
27 #include <linux/platform_device.h>
28 #include <linux/printk.h>
29 
30 #include <soc/at91/at91sam9_ddrsdr.h>
31 
32 #define SLOW_CLOCK_FREQ	32768
33 
34 #define AT91_SHDW_CR	0x00		/* Shut Down Control Register */
35 #define AT91_SHDW_SHDW		BIT(0)			/* Shut Down command */
36 #define AT91_SHDW_KEY		(0xa5UL << 24)		/* KEY Password */
37 
38 #define AT91_SHDW_MR	0x04		/* Shut Down Mode Register */
39 #define AT91_SHDW_WKUPDBC_SHIFT	24
40 #define AT91_SHDW_WKUPDBC_MASK	GENMASK(26, 24)
41 #define AT91_SHDW_WKUPDBC(x)	(((x) << AT91_SHDW_WKUPDBC_SHIFT) \
42 						& AT91_SHDW_WKUPDBC_MASK)
43 
44 #define AT91_SHDW_SR	0x08		/* Shut Down Status Register */
45 #define AT91_SHDW_WKUPIS_SHIFT	16
46 #define AT91_SHDW_WKUPIS_MASK	GENMASK(31, 16)
47 #define AT91_SHDW_WKUPIS(x)	((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
48 						& AT91_SHDW_WKUPIS_MASK)
49 
50 #define AT91_SHDW_WUIR	0x0c		/* Shutdown Wake-up Inputs Register */
51 #define AT91_SHDW_WKUPEN_MASK	GENMASK(15, 0)
52 #define AT91_SHDW_WKUPEN(x)	((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
53 #define AT91_SHDW_WKUPT_SHIFT	16
54 #define AT91_SHDW_WKUPT_MASK	GENMASK(31, 16)
55 #define AT91_SHDW_WKUPT(x)	((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
56 						& AT91_SHDW_WKUPT_MASK)
57 
58 #define SHDW_WK_PIN(reg, cfg)	((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
59 #define SHDW_RTCWK(reg, cfg)	(((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
60 #define SHDW_RTTWK(reg, cfg)	(((reg) >> ((cfg)->sr_rttwk_shift)) & 0x1)
61 #define SHDW_RTCWKEN(cfg)	(1 << ((cfg)->mr_rtcwk_shift))
62 #define SHDW_RTTWKEN(cfg)	(1 << ((cfg)->mr_rttwk_shift))
63 
64 #define DBC_PERIOD_US(x)	DIV_ROUND_UP_ULL((1000000 * (x)), \
65 							SLOW_CLOCK_FREQ)
66 
67 #define SHDW_CFG_NOT_USED	(32)
68 
69 struct shdwc_reg_config {
70 	u8 wkup_pin_input;
71 	u8 mr_rtcwk_shift;
72 	u8 mr_rttwk_shift;
73 	u8 sr_rtcwk_shift;
74 	u8 sr_rttwk_shift;
75 };
76 
77 struct pmc_reg_config {
78 	u8 mckr;
79 };
80 
81 struct ddrc_reg_config {
82 	u32 type_offset;
83 	u32 type_mask;
84 };
85 
86 struct reg_config {
87 	struct shdwc_reg_config shdwc;
88 	struct pmc_reg_config pmc;
89 	struct ddrc_reg_config ddrc;
90 };
91 
92 struct shdwc {
93 	const struct reg_config *rcfg;
94 	struct clk *sclk;
95 	void __iomem *shdwc_base;
96 	void __iomem *mpddrc_base;
97 	void __iomem *pmc_base;
98 };
99 
100 /*
101  * Hold configuration here, cannot be more than one instance of the driver
102  * since pm_power_off itself is global.
103  */
104 static struct shdwc *at91_shdwc;
105 
106 static const unsigned long long sdwc_dbc_period[] = {
107 	0, 3, 32, 512, 4096, 32768,
108 };
109 
110 static void __init at91_wakeup_status(struct platform_device *pdev)
111 {
112 	struct shdwc *shdw = platform_get_drvdata(pdev);
113 	const struct reg_config *rcfg = shdw->rcfg;
114 	u32 reg;
115 	char *reason = "unknown";
116 
117 	reg = readl(shdw->shdwc_base + AT91_SHDW_SR);
118 
119 	dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);
120 
121 	/* Simple power-on, just bail out */
122 	if (!reg)
123 		return;
124 
125 	if (SHDW_WK_PIN(reg, &rcfg->shdwc))
126 		reason = "WKUP pin";
127 	else if (SHDW_RTCWK(reg, &rcfg->shdwc))
128 		reason = "RTC";
129 	else if (SHDW_RTTWK(reg, &rcfg->shdwc))
130 		reason = "RTT";
131 
132 	pr_info("AT91: Wake-Up source: %s\n", reason);
133 }
134 
135 static void at91_poweroff(void)
136 {
137 	asm volatile(
138 		/* Align to cache lines */
139 		".balign 32\n\t"
140 
141 		/* Ensure AT91_SHDW_CR is in the TLB by reading it */
142 		"	ldr	r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
143 
144 		/* Power down SDRAM0 */
145 		"	tst	%0, #0\n\t"
146 		"	beq	1f\n\t"
147 		"	str	%1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
148 
149 		/* Switch the master clock source to slow clock. */
150 		"1:	ldr	r6, [%4, %5]\n\t"
151 		"	bic	r6, r6,  #" __stringify(AT91_PMC_CSS) "\n\t"
152 		"	str	r6, [%4, %5]\n\t"
153 		/* Wait for clock switch. */
154 		"2:	ldr	r6, [%4, #" __stringify(AT91_PMC_SR) "]\n\t"
155 		"	tst	r6, #"	    __stringify(AT91_PMC_MCKRDY) "\n\t"
156 		"	beq	2b\n\t"
157 
158 		/* Shutdown CPU */
159 		"	str	%3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
160 
161 		"	b	.\n\t"
162 		:
163 		: "r" (at91_shdwc->mpddrc_base),
164 		  "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
165 		  "r" (at91_shdwc->shdwc_base),
166 		  "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW),
167 		  "r" (at91_shdwc->pmc_base),
168 		  "r" (at91_shdwc->rcfg->pmc.mckr)
169 		: "r6");
170 }
171 
172 static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
173 				      u32 in_period_us)
174 {
175 	int i;
176 	int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
177 	unsigned long long period_us;
178 	unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);
179 
180 	if (in_period_us > max_period_us) {
181 		dev_warn(&pdev->dev,
182 			 "debouncer period %u too big, reduced to %llu us\n",
183 			 in_period_us, max_period_us);
184 		return max_idx;
185 	}
186 
187 	for (i = max_idx - 1; i > 0; i--) {
188 		period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
189 		dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
190 						__func__, i, period_us);
191 		if (in_period_us > period_us)
192 			break;
193 	}
194 
195 	return i + 1;
196 }
197 
198 static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
199 				       struct device_node *np)
200 {
201 	struct device_node *cnp;
202 	u32 wk_input_mask;
203 	u32 wuir = 0;
204 	u32 wk_input;
205 
206 	for_each_child_of_node(np, cnp) {
207 		if (of_property_read_u32(cnp, "reg", &wk_input)) {
208 			dev_warn(&pdev->dev, "reg property is missing for %pOF\n",
209 				 cnp);
210 			continue;
211 		}
212 
213 		wk_input_mask = 1 << wk_input;
214 		if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
215 			dev_warn(&pdev->dev,
216 				 "wake-up input %d out of bounds ignore\n",
217 				 wk_input);
218 			continue;
219 		}
220 		wuir |= wk_input_mask;
221 
222 		if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
223 			wuir |= AT91_SHDW_WKUPT(wk_input);
224 
225 		dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
226 						__func__, wk_input, wuir);
227 	}
228 
229 	return wuir;
230 }
231 
232 static void at91_shdwc_dt_configure(struct platform_device *pdev)
233 {
234 	struct shdwc *shdw = platform_get_drvdata(pdev);
235 	const struct reg_config *rcfg = shdw->rcfg;
236 	struct device_node *np = pdev->dev.of_node;
237 	u32 mode = 0, tmp, input;
238 
239 	if (!np) {
240 		dev_err(&pdev->dev, "device node not found\n");
241 		return;
242 	}
243 
244 	if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
245 		mode |= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));
246 
247 	if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
248 		mode |= SHDW_RTCWKEN(&rcfg->shdwc);
249 
250 	if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
251 		mode |= SHDW_RTTWKEN(&rcfg->shdwc);
252 
253 	dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
254 	writel(mode, shdw->shdwc_base + AT91_SHDW_MR);
255 
256 	input = at91_shdwc_get_wakeup_input(pdev, np);
257 	writel(input, shdw->shdwc_base + AT91_SHDW_WUIR);
258 }
259 
260 static const struct reg_config sama5d2_reg_config = {
261 	.shdwc = {
262 		.wkup_pin_input = 0,
263 		.mr_rtcwk_shift = 17,
264 		.mr_rttwk_shift	= SHDW_CFG_NOT_USED,
265 		.sr_rtcwk_shift = 5,
266 		.sr_rttwk_shift = SHDW_CFG_NOT_USED,
267 	},
268 	.pmc = {
269 		.mckr		= 0x30,
270 	},
271 	.ddrc = {
272 		.type_offset	= AT91_DDRSDRC_MDR,
273 		.type_mask	= AT91_DDRSDRC_MD
274 	},
275 };
276 
277 static const struct reg_config sam9x60_reg_config = {
278 	.shdwc = {
279 		.wkup_pin_input = 0,
280 		.mr_rtcwk_shift = 17,
281 		.mr_rttwk_shift = 16,
282 		.sr_rtcwk_shift = 5,
283 		.sr_rttwk_shift = 4,
284 	},
285 	.pmc = {
286 		.mckr		= 0x28,
287 	},
288 	.ddrc = {
289 		.type_offset	= AT91_DDRSDRC_MDR,
290 		.type_mask	= AT91_DDRSDRC_MD
291 	},
292 };
293 
294 static const struct reg_config sama7g5_reg_config = {
295 	.shdwc = {
296 		.wkup_pin_input = 0,
297 		.mr_rtcwk_shift = 17,
298 		.mr_rttwk_shift = 16,
299 		.sr_rtcwk_shift = 5,
300 		.sr_rttwk_shift = 4,
301 	},
302 	.pmc = {
303 		.mckr		= 0x28,
304 	},
305 };
306 
307 static const struct of_device_id at91_shdwc_of_match[] = {
308 	{
309 		.compatible = "atmel,sama5d2-shdwc",
310 		.data = &sama5d2_reg_config,
311 	},
312 	{
313 		.compatible = "microchip,sam9x60-shdwc",
314 		.data = &sam9x60_reg_config,
315 	},
316 	{
317 		.compatible = "microchip,sama7g5-shdwc",
318 		.data = &sama7g5_reg_config,
319 	}, {
320 		/*sentinel*/
321 	}
322 };
323 MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);
324 
325 static const struct of_device_id at91_pmc_ids[] = {
326 	{ .compatible = "atmel,sama5d2-pmc" },
327 	{ .compatible = "microchip,sam9x60-pmc" },
328 	{ .compatible = "microchip,sama7g5-pmc" },
329 	{ /* Sentinel. */ }
330 };
331 
332 static int __init at91_shdwc_probe(struct platform_device *pdev)
333 {
334 	const struct of_device_id *match;
335 	struct device_node *np;
336 	u32 ddr_type;
337 	int ret;
338 
339 	if (!pdev->dev.of_node)
340 		return -ENODEV;
341 
342 	if (at91_shdwc)
343 		return -EBUSY;
344 
345 	at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
346 	if (!at91_shdwc)
347 		return -ENOMEM;
348 
349 	platform_set_drvdata(pdev, at91_shdwc);
350 
351 	at91_shdwc->shdwc_base = devm_platform_ioremap_resource(pdev, 0);
352 	if (IS_ERR(at91_shdwc->shdwc_base))
353 		return PTR_ERR(at91_shdwc->shdwc_base);
354 
355 	match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
356 	at91_shdwc->rcfg = match->data;
357 
358 	at91_shdwc->sclk = devm_clk_get(&pdev->dev, NULL);
359 	if (IS_ERR(at91_shdwc->sclk))
360 		return PTR_ERR(at91_shdwc->sclk);
361 
362 	ret = clk_prepare_enable(at91_shdwc->sclk);
363 	if (ret) {
364 		dev_err(&pdev->dev, "Could not enable slow clock\n");
365 		return ret;
366 	}
367 
368 	at91_wakeup_status(pdev);
369 
370 	at91_shdwc_dt_configure(pdev);
371 
372 	np = of_find_matching_node(NULL, at91_pmc_ids);
373 	if (!np) {
374 		ret = -ENODEV;
375 		goto clk_disable;
376 	}
377 
378 	at91_shdwc->pmc_base = of_iomap(np, 0);
379 	of_node_put(np);
380 
381 	if (!at91_shdwc->pmc_base) {
382 		ret = -ENOMEM;
383 		goto clk_disable;
384 	}
385 
386 	if (at91_shdwc->rcfg->ddrc.type_mask) {
387 		np = of_find_compatible_node(NULL, NULL,
388 					     "atmel,sama5d3-ddramc");
389 		if (!np) {
390 			ret = -ENODEV;
391 			goto unmap;
392 		}
393 
394 		at91_shdwc->mpddrc_base = of_iomap(np, 0);
395 		of_node_put(np);
396 
397 		if (!at91_shdwc->mpddrc_base) {
398 			ret = -ENOMEM;
399 			goto unmap;
400 		}
401 
402 		ddr_type = readl(at91_shdwc->mpddrc_base +
403 				 at91_shdwc->rcfg->ddrc.type_offset) &
404 				 at91_shdwc->rcfg->ddrc.type_mask;
405 		if (ddr_type != AT91_DDRSDRC_MD_LPDDR2 &&
406 		    ddr_type != AT91_DDRSDRC_MD_LPDDR3) {
407 			iounmap(at91_shdwc->mpddrc_base);
408 			at91_shdwc->mpddrc_base = NULL;
409 		}
410 	}
411 
412 	pm_power_off = at91_poweroff;
413 
414 	return 0;
415 
416 unmap:
417 	iounmap(at91_shdwc->pmc_base);
418 clk_disable:
419 	clk_disable_unprepare(at91_shdwc->sclk);
420 
421 	return ret;
422 }
423 
424 static int __exit at91_shdwc_remove(struct platform_device *pdev)
425 {
426 	struct shdwc *shdw = platform_get_drvdata(pdev);
427 
428 	if (pm_power_off == at91_poweroff)
429 		pm_power_off = NULL;
430 
431 	/* Reset values to disable wake-up features  */
432 	writel(0, shdw->shdwc_base + AT91_SHDW_MR);
433 	writel(0, shdw->shdwc_base + AT91_SHDW_WUIR);
434 
435 	if (shdw->mpddrc_base)
436 		iounmap(shdw->mpddrc_base);
437 	iounmap(shdw->pmc_base);
438 
439 	clk_disable_unprepare(shdw->sclk);
440 
441 	return 0;
442 }
443 
444 static struct platform_driver at91_shdwc_driver = {
445 	.remove = __exit_p(at91_shdwc_remove),
446 	.driver = {
447 		.name = "at91-shdwc",
448 		.of_match_table = at91_shdwc_of_match,
449 	},
450 };
451 module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);
452 
453 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
454 MODULE_DESCRIPTION("Atmel shutdown controller driver");
455 MODULE_LICENSE("GPL v2");
456