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
at91_wakeup_status(struct platform_device * pdev)110 static void 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
at91_poweroff(void)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
at91_shdwc_debouncer_value(struct platform_device * pdev,u32 in_period_us)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
at91_shdwc_get_wakeup_input(struct platform_device * pdev,struct device_node * np)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
at91_shdwc_dt_configure(struct platform_device * pdev)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
at91_shdwc_probe(struct platform_device * pdev)332 static int 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
at91_shdwc_remove(struct platform_device * pdev)424 static void 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
442 static struct platform_driver at91_shdwc_driver = {
443 .probe = at91_shdwc_probe,
444 .remove_new = at91_shdwc_remove,
445 .driver = {
446 .name = "at91-shdwc",
447 .of_match_table = at91_shdwc_of_match,
448 },
449 };
450 module_platform_driver(at91_shdwc_driver);
451
452 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
453 MODULE_DESCRIPTION("Atmel shutdown controller driver");
454 MODULE_LICENSE("GPL v2");
455