drivers/power/reset/at91-sama5d2_shdwc.c

   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(31, 16)
  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_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 shdwc {
  78         const struct shdwc_config *cfg;
  79         struct clk *sclk;
  80         void __iomem *shdwc_base;
  81         void __iomem *mpddrc_base;
  82         void __iomem *pmc_base;
  83 };
  84
  85 /*
  86  * Hold configuration here, cannot be more than one instance of the driver
  87  * since pm_power_off itself is global.
  88  */
  89 static struct shdwc *at91_shdwc;
  90
  91 static const unsigned long long sdwc_dbc_period[] = {
  92         0, 3, 32, 512, 4096, 32768,
  93 };
  94
  95 static void __init at91_wakeup_status(struct platform_device *pdev)
  96 {
  97         struct shdwc *shdw = platform_get_drvdata(pdev);
  98         u32 reg;
  99         char *reason = "unknown";
 100
 101         reg = readl(shdw->shdwc_base + AT91_SHDW_SR);
 102
 103         dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);
 104
 105         /* Simple power-on, just bail out */
 106         if (!reg)
 107                 return;
 108
 109         if (SHDW_WK_PIN(reg, shdw->cfg))
 110                 reason = "WKUP pin";
 111         else if (SHDW_RTCWK(reg, shdw->cfg))
 112                 reason = "RTC";
 113         else if (SHDW_RTTWK(reg, shdw->cfg))
 114                 reason = "RTT";
 115
 116         pr_info("AT91: Wake-Up source: %s\n", reason);
 117 }
 118
 119 static void at91_poweroff(void)
 120 {
 121         asm volatile(
 122                 /* Align to cache lines */
 123                 ".balign 32\n\t"
 124
 125                 /* Ensure AT91_SHDW_CR is in the TLB by reading it */
 126                 "       ldr     r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
 127
 128                 /* Power down SDRAM0 */
 129                 "       tst     %0, #0\n\t"
 130                 "       beq     1f\n\t"
 131                 "       str     %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
 132
 133                 /* Switch the master clock source to slow clock. */
 134                 "1:     ldr     r6, [%4, #" __stringify(AT91_PMC_MCKR) "]\n\t"
 135                 "       bic     r6, r6,  #" __stringify(AT91_PMC_CSS) "\n\t"
 136                 "       str     r6, [%4, #" __stringify(AT91_PMC_MCKR) "]\n\t"
 137                 /* Wait for clock switch. */
 138                 "2:     ldr     r6, [%4, #" __stringify(AT91_PMC_SR) "]\n\t"
 139                 "       tst     r6, #"      __stringify(AT91_PMC_MCKRDY) "\n\t"
 140                 "       beq     2b\n\t"
 141
 142                 /* Shutdown CPU */
 143                 "       str     %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
 144
 145                 "       b       .\n\t"
 146                 :
 147                 : "r" (at91_shdwc->mpddrc_base),
 148                   "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
 149                   "r" (at91_shdwc->shdwc_base),
 150                   "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW),
 151                   "r" (at91_shdwc->pmc_base)
 152                 : "r6");
 153 }
 154
 155 static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
 156                                       u32 in_period_us)
 157 {
 158         int i;
 159         int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
 160         unsigned long long period_us;
 161         unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);
 162
 163         if (in_period_us > max_period_us) {
 164                 dev_warn(&pdev->dev,
 165                          "debouncer period %u too big, reduced to %llu us\n",
 166                          in_period_us, max_period_us);
 167                 return max_idx;
 168         }
 169
 170         for (i = max_idx - 1; i > 0; i--) {
 171                 period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
 172                 dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
 173                                                 __func__, i, period_us);
 174                 if (in_period_us > period_us)
 175                         break;
 176         }
 177
 178         return i + 1;
 179 }
 180
 181 static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
 182                                        struct device_node *np)
 183 {
 184         struct device_node *cnp;
 185         u32 wk_input_mask;
 186         u32 wuir = 0;
 187         u32 wk_input;
 188
 189         for_each_child_of_node(np, cnp) {
 190                 if (of_property_read_u32(cnp, "reg", &wk_input)) {
 191                         dev_warn(&pdev->dev, "reg property is missing for %pOF\n",
 192                                  cnp);
 193                         continue;
 194                 }
 195
 196                 wk_input_mask = 1 << wk_input;
 197                 if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
 198                         dev_warn(&pdev->dev,
 199                                  "wake-up input %d out of bounds ignore\n",
 200                                  wk_input);
 201                         continue;
 202                 }
 203                 wuir |= wk_input_mask;
 204
 205                 if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
 206                         wuir |= AT91_SHDW_WKUPT(wk_input);
 207
 208                 dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
 209                                                 __func__, wk_input, wuir);
 210         }
 211
 212         return wuir;
 213 }
 214
 215 static void at91_shdwc_dt_configure(struct platform_device *pdev)
 216 {
 217         struct shdwc *shdw = platform_get_drvdata(pdev);
 218         struct device_node *np = pdev->dev.of_node;
 219         u32 mode = 0, tmp, input;
 220
 221         if (!np) {
 222                 dev_err(&pdev->dev, "device node not found\n");
 223                 return;
 224         }
 225
 226         if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
 227                 mode |= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));
 228
 229         if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
 230                 mode |= SHDW_RTCWKEN(shdw->cfg);
 231
 232         if (of_property_read_bool(np, "atmel,wakeup-rtt-timer"))
 233                 mode |= SHDW_RTTWKEN(shdw->cfg);
 234
 235         dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
 236         writel(mode, shdw->shdwc_base + AT91_SHDW_MR);
 237
 238         input = at91_shdwc_get_wakeup_input(pdev, np);
 239         writel(input, shdw->shdwc_base + AT91_SHDW_WUIR);
 240 }
 241
 242 static const struct shdwc_config sama5d2_shdwc_config = {
 243         .wkup_pin_input = 0,
 244         .mr_rtcwk_shift = 17,
 245         .mr_rttwk_shift = SHDW_CFG_NOT_USED,
 246         .sr_rtcwk_shift = 5,
 247         .sr_rttwk_shift = SHDW_CFG_NOT_USED,
 248 };
 249
 250 static const struct shdwc_config sam9x60_shdwc_config = {
 251         .wkup_pin_input = 0,
 252         .mr_rtcwk_shift = 17,
 253         .mr_rttwk_shift = 16,
 254         .sr_rtcwk_shift = 5,
 255         .sr_rttwk_shift = 4,
 256 };
 257
 258 static const struct of_device_id at91_shdwc_of_match[] = {
 259         {
 260                 .compatible = "atmel,sama5d2-shdwc",
 261                 .data = &sama5d2_shdwc_config,
 262         },
 263         {
 264                 .compatible = "microchip,sam9x60-shdwc",
 265                 .data = &sam9x60_shdwc_config,
 266         }, {
 267                 /*sentinel*/
 268         }
 269 };
 270 MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);
 271
 272 static int __init at91_shdwc_probe(struct platform_device *pdev)
 273 {
 274         struct resource *res;
 275         const struct of_device_id *match;
 276         struct device_node *np;
 277         u32 ddr_type;
 278         int ret;
 279
 280         if (!pdev->dev.of_node)
 281                 return -ENODEV;
 282
 283         if (at91_shdwc)
 284                 return -EBUSY;
 285
 286         at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
 287         if (!at91_shdwc)
 288                 return -ENOMEM;
 289
 290         platform_set_drvdata(pdev, at91_shdwc);
 291
 292         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 293         at91_shdwc->shdwc_base = devm_ioremap_resource(&pdev->dev, res);
 294         if (IS_ERR(at91_shdwc->shdwc_base)) {
 295                 dev_err(&pdev->dev, "Could not map reset controller address\n");
 296                 return PTR_ERR(at91_shdwc->shdwc_base);
 297         }
 298
 299         match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
 300         at91_shdwc->cfg = match->data;
 301
 302         at91_shdwc->sclk = devm_clk_get(&pdev->dev, NULL);
 303         if (IS_ERR(at91_shdwc->sclk))
 304                 return PTR_ERR(at91_shdwc->sclk);
 305
 306         ret = clk_prepare_enable(at91_shdwc->sclk);
 307         if (ret) {
 308                 dev_err(&pdev->dev, "Could not enable slow clock\n");
 309                 return ret;
 310         }
 311
 312         at91_wakeup_status(pdev);
 313
 314         at91_shdwc_dt_configure(pdev);
 315
 316         np = of_find_compatible_node(NULL, NULL, "atmel,sama5d2-pmc");
 317         if (!np) {
 318                 ret = -ENODEV;
 319                 goto clk_disable;
 320         }
 321
 322         at91_shdwc->pmc_base = of_iomap(np, 0);
 323         of_node_put(np);
 324
 325         if (!at91_shdwc->pmc_base) {
 326                 ret = -ENOMEM;
 327                 goto clk_disable;
 328         }
 329
 330         np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
 331         if (!np) {
 332                 ret = -ENODEV;
 333                 goto unmap;
 334         }
 335
 336         at91_shdwc->mpddrc_base = of_iomap(np, 0);
 337         of_node_put(np);
 338
 339         if (!at91_shdwc->mpddrc_base) {
 340                 ret = -ENOMEM;
 341                 goto unmap;
 342         }
 343
 344         pm_power_off = at91_poweroff;
 345
 346         ddr_type = readl(at91_shdwc->mpddrc_base + AT91_DDRSDRC_MDR) &
 347                          AT91_DDRSDRC_MD;
 348         if (ddr_type != AT91_DDRSDRC_MD_LPDDR2 &&
 349             ddr_type != AT91_DDRSDRC_MD_LPDDR3) {
 350                 iounmap(at91_shdwc->mpddrc_base);
 351                 at91_shdwc->mpddrc_base = NULL;
 352         }
 353
 354         return 0;
 355
 356 unmap:
 357         iounmap(at91_shdwc->pmc_base);
 358 clk_disable:
 359         clk_disable_unprepare(at91_shdwc->sclk);
 360
 361         return ret;
 362 }
 363
 364 static int __exit at91_shdwc_remove(struct platform_device *pdev)
 365 {
 366         struct shdwc *shdw = platform_get_drvdata(pdev);
 367
 368         if (pm_power_off == at91_poweroff)
 369                 pm_power_off = NULL;
 370
 371         /* Reset values to disable wake-up features  */
 372         writel(0, shdw->shdwc_base + AT91_SHDW_MR);
 373         writel(0, shdw->shdwc_base + AT91_SHDW_WUIR);
 374
 375         if (shdw->mpddrc_base)
 376                 iounmap(shdw->mpddrc_base);
 377         iounmap(shdw->pmc_base);
 378
 379         clk_disable_unprepare(shdw->sclk);
 380
 381         return 0;
 382 }
 383
 384 static struct platform_driver at91_shdwc_driver = {
 385         .remove = __exit_p(at91_shdwc_remove),
 386         .driver = {
 387                 .name = "at91-shdwc",
 388                 .of_match_table = at91_shdwc_of_match,
 389         },
 390 };
 391 module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);
 392
 393 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
 394 MODULE_DESCRIPTION("Atmel shutdown controller driver");
 395 MODULE_LICENSE("GPL v2");