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/io.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/of_address.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/printk.h>
  28
  29 #include <soc/at91/at91sam9_ddrsdr.h>
  30
  31 #define SLOW_CLOCK_FREQ 32768
  32
  33 #define AT91_SHDW_CR    0x00            /* Shut Down Control Register */
  34 #define AT91_SHDW_SHDW          BIT(0)                  /* Shut Down command */
  35 #define AT91_SHDW_KEY           (0xa5UL << 24)          /* KEY Password */
  36
  37 #define AT91_SHDW_MR    0x04            /* Shut Down Mode Register */
  38 #define AT91_SHDW_WKUPDBC_SHIFT 24
  39 #define AT91_SHDW_WKUPDBC_MASK  GENMASK(26, 24)
  40 #define AT91_SHDW_WKUPDBC(x)    (((x) << AT91_SHDW_WKUPDBC_SHIFT) \
  41                                                 & AT91_SHDW_WKUPDBC_MASK)
  42
  43 #define AT91_SHDW_SR    0x08            /* Shut Down Status Register */
  44 #define AT91_SHDW_WKUPIS_SHIFT  16
  45 #define AT91_SHDW_WKUPIS_MASK   GENMASK(31, 16)
  46 #define AT91_SHDW_WKUPIS(x)     ((1 << (x)) << AT91_SHDW_WKUPIS_SHIFT \
  47                                                 & AT91_SHDW_WKUPIS_MASK)
  48
  49 #define AT91_SHDW_WUIR  0x0c            /* Shutdown Wake-up Inputs Register */
  50 #define AT91_SHDW_WKUPEN_MASK   GENMASK(15, 0)
  51 #define AT91_SHDW_WKUPEN(x)     ((1 << (x)) & AT91_SHDW_WKUPEN_MASK)
  52 #define AT91_SHDW_WKUPT_SHIFT   16
  53 #define AT91_SHDW_WKUPT_MASK    GENMASK(31, 16)
  54 #define AT91_SHDW_WKUPT(x)      ((1 << (x)) << AT91_SHDW_WKUPT_SHIFT \
  55                                                 & AT91_SHDW_WKUPT_MASK)
  56
  57 #define SHDW_WK_PIN(reg, cfg)   ((reg) & AT91_SHDW_WKUPIS((cfg)->wkup_pin_input))
  58 #define SHDW_RTCWK(reg, cfg)    (((reg) >> ((cfg)->sr_rtcwk_shift)) & 0x1)
  59 #define SHDW_RTCWKEN(cfg)       (1 << ((cfg)->mr_rtcwk_shift))
  60
  61 #define DBC_PERIOD_US(x)        DIV_ROUND_UP_ULL((1000000 * (x)), \
  62                                                         SLOW_CLOCK_FREQ)
  63
  64 struct shdwc_config {
  65         u8 wkup_pin_input;
  66         u8 mr_rtcwk_shift;
  67         u8 sr_rtcwk_shift;
  68 };
  69
  70 struct shdwc {
  71         struct shdwc_config *cfg;
  72         void __iomem *at91_shdwc_base;
  73 };
  74
  75 /*
  76  * Hold configuration here, cannot be more than one instance of the driver
  77  * since pm_power_off itself is global.
  78  */
  79 static struct shdwc *at91_shdwc;
  80 static struct clk *sclk;
  81 static void __iomem *mpddrc_base;
  82
  83 static const unsigned long long sdwc_dbc_period[] = {
  84         0, 3, 32, 512, 4096, 32768,
  85 };
  86
  87 static void __init at91_wakeup_status(struct platform_device *pdev)
  88 {
  89         struct shdwc *shdw = platform_get_drvdata(pdev);
  90         u32 reg;
  91         char *reason = "unknown";
  92
  93         reg = readl(shdw->at91_shdwc_base + AT91_SHDW_SR);
  94
  95         dev_dbg(&pdev->dev, "%s: status = %#x\n", __func__, reg);
  96
  97         /* Simple power-on, just bail out */
  98         if (!reg)
  99                 return;
 100
 101         if (SHDW_WK_PIN(reg, shdw->cfg))
 102                 reason = "WKUP pin";
 103         else if (SHDW_RTCWK(reg, shdw->cfg))
 104                 reason = "RTC";
 105
 106         pr_info("AT91: Wake-Up source: %s\n", reason);
 107 }
 108
 109 static void at91_poweroff(void)
 110 {
 111         writel(AT91_SHDW_KEY | AT91_SHDW_SHDW,
 112                at91_shdwc->at91_shdwc_base + AT91_SHDW_CR);
 113 }
 114
 115 static void at91_lpddr_poweroff(void)
 116 {
 117         asm volatile(
 118                 /* Align to cache lines */
 119                 ".balign 32\n\t"
 120
 121                 /* Ensure AT91_SHDW_CR is in the TLB by reading it */
 122                 "       ldr     r6, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
 123
 124                 /* Power down SDRAM0 */
 125                 "       str     %1, [%0, #" __stringify(AT91_DDRSDRC_LPR) "]\n\t"
 126                 /* Shutdown CPU */
 127                 "       str     %3, [%2, #" __stringify(AT91_SHDW_CR) "]\n\t"
 128
 129                 "       b       .\n\t"
 130                 :
 131                 : "r" (mpddrc_base),
 132                   "r" cpu_to_le32(AT91_DDRSDRC_LPDDR2_PWOFF),
 133                   "r" (at91_shdwc->at91_shdwc_base),
 134                   "r" cpu_to_le32(AT91_SHDW_KEY | AT91_SHDW_SHDW)
 135                 : "r6");
 136 }
 137
 138 static u32 at91_shdwc_debouncer_value(struct platform_device *pdev,
 139                                       u32 in_period_us)
 140 {
 141         int i;
 142         int max_idx = ARRAY_SIZE(sdwc_dbc_period) - 1;
 143         unsigned long long period_us;
 144         unsigned long long max_period_us = DBC_PERIOD_US(sdwc_dbc_period[max_idx]);
 145
 146         if (in_period_us > max_period_us) {
 147                 dev_warn(&pdev->dev,
 148                          "debouncer period %u too big, reduced to %llu us\n",
 149                          in_period_us, max_period_us);
 150                 return max_idx;
 151         }
 152
 153         for (i = max_idx - 1; i > 0; i--) {
 154                 period_us = DBC_PERIOD_US(sdwc_dbc_period[i]);
 155                 dev_dbg(&pdev->dev, "%s: ref[%d] = %llu\n",
 156                                                 __func__, i, period_us);
 157                 if (in_period_us > period_us)
 158                         break;
 159         }
 160
 161         return i + 1;
 162 }
 163
 164 static u32 at91_shdwc_get_wakeup_input(struct platform_device *pdev,
 165                                        struct device_node *np)
 166 {
 167         struct device_node *cnp;
 168         u32 wk_input_mask;
 169         u32 wuir = 0;
 170         u32 wk_input;
 171
 172         for_each_child_of_node(np, cnp) {
 173                 if (of_property_read_u32(cnp, "reg", &wk_input)) {
 174                         dev_warn(&pdev->dev, "reg property is missing for %pOF\n",
 175                                  cnp);
 176                         continue;
 177                 }
 178
 179                 wk_input_mask = 1 << wk_input;
 180                 if (!(wk_input_mask & AT91_SHDW_WKUPEN_MASK)) {
 181                         dev_warn(&pdev->dev,
 182                                  "wake-up input %d out of bounds ignore\n",
 183                                  wk_input);
 184                         continue;
 185                 }
 186                 wuir |= wk_input_mask;
 187
 188                 if (of_property_read_bool(cnp, "atmel,wakeup-active-high"))
 189                         wuir |= AT91_SHDW_WKUPT(wk_input);
 190
 191                 dev_dbg(&pdev->dev, "%s: (child %d) wuir = %#x\n",
 192                                                 __func__, wk_input, wuir);
 193         }
 194
 195         return wuir;
 196 }
 197
 198 static void at91_shdwc_dt_configure(struct platform_device *pdev)
 199 {
 200         struct shdwc *shdw = platform_get_drvdata(pdev);
 201         struct device_node *np = pdev->dev.of_node;
 202         u32 mode = 0, tmp, input;
 203
 204         if (!np) {
 205                 dev_err(&pdev->dev, "device node not found\n");
 206                 return;
 207         }
 208
 209         if (!of_property_read_u32(np, "debounce-delay-us", &tmp))
 210                 mode |= AT91_SHDW_WKUPDBC(at91_shdwc_debouncer_value(pdev, tmp));
 211
 212         if (of_property_read_bool(np, "atmel,wakeup-rtc-timer"))
 213                 mode |= SHDW_RTCWKEN(shdw->cfg);
 214
 215         dev_dbg(&pdev->dev, "%s: mode = %#x\n", __func__, mode);
 216         writel(mode, shdw->at91_shdwc_base + AT91_SHDW_MR);
 217
 218         input = at91_shdwc_get_wakeup_input(pdev, np);
 219         writel(input, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
 220 }
 221
 222 static const struct shdwc_config sama5d2_shdwc_config = {
 223         .wkup_pin_input = 0,
 224         .mr_rtcwk_shift = 17,
 225         .sr_rtcwk_shift = 5,
 226 };
 227
 228 static const struct of_device_id at91_shdwc_of_match[] = {
 229         {
 230                 .compatible = "atmel,sama5d2-shdwc",
 231                 .data = &sama5d2_shdwc_config,
 232         }, {
 233                 /*sentinel*/
 234         }
 235 };
 236 MODULE_DEVICE_TABLE(of, at91_shdwc_of_match);
 237
 238 static int __init at91_shdwc_probe(struct platform_device *pdev)
 239 {
 240         struct resource *res;
 241         const struct of_device_id *match;
 242         struct device_node *np;
 243         u32 ddr_type;
 244         int ret;
 245
 246         if (!pdev->dev.of_node)
 247                 return -ENODEV;
 248
 249         if (at91_shdwc)
 250                 return -EBUSY;
 251
 252         at91_shdwc = devm_kzalloc(&pdev->dev, sizeof(*at91_shdwc), GFP_KERNEL);
 253         if (!at91_shdwc)
 254                 return -ENOMEM;
 255
 256         platform_set_drvdata(pdev, at91_shdwc);
 257
 258         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 259         at91_shdwc->at91_shdwc_base = devm_ioremap_resource(&pdev->dev, res);
 260         if (IS_ERR(at91_shdwc->at91_shdwc_base)) {
 261                 dev_err(&pdev->dev, "Could not map reset controller address\n");
 262                 return PTR_ERR(at91_shdwc->at91_shdwc_base);
 263         }
 264
 265         match = of_match_node(at91_shdwc_of_match, pdev->dev.of_node);
 266         at91_shdwc->cfg = (struct shdwc_config *)(match->data);
 267
 268         sclk = devm_clk_get(&pdev->dev, NULL);
 269         if (IS_ERR(sclk))
 270                 return PTR_ERR(sclk);
 271
 272         ret = clk_prepare_enable(sclk);
 273         if (ret) {
 274                 dev_err(&pdev->dev, "Could not enable slow clock\n");
 275                 return ret;
 276         }
 277
 278         at91_wakeup_status(pdev);
 279
 280         at91_shdwc_dt_configure(pdev);
 281
 282         pm_power_off = at91_poweroff;
 283
 284         np = of_find_compatible_node(NULL, NULL, "atmel,sama5d3-ddramc");
 285         if (!np)
 286                 return 0;
 287
 288         mpddrc_base = of_iomap(np, 0);
 289         of_node_put(np);
 290
 291         if (!mpddrc_base)
 292                 return 0;
 293
 294         ddr_type = readl(mpddrc_base + AT91_DDRSDRC_MDR) & AT91_DDRSDRC_MD;
 295         if ((ddr_type == AT91_DDRSDRC_MD_LPDDR2) ||
 296             (ddr_type == AT91_DDRSDRC_MD_LPDDR3))
 297                 pm_power_off = at91_lpddr_poweroff;
 298         else
 299                 iounmap(mpddrc_base);
 300
 301         return 0;
 302 }
 303
 304 static int __exit at91_shdwc_remove(struct platform_device *pdev)
 305 {
 306         struct shdwc *shdw = platform_get_drvdata(pdev);
 307
 308         if (pm_power_off == at91_poweroff ||
 309             pm_power_off == at91_lpddr_poweroff)
 310                 pm_power_off = NULL;
 311
 312         /* Reset values to disable wake-up features  */
 313         writel(0, shdw->at91_shdwc_base + AT91_SHDW_MR);
 314         writel(0, shdw->at91_shdwc_base + AT91_SHDW_WUIR);
 315
 316         clk_disable_unprepare(sclk);
 317
 318         return 0;
 319 }
 320
 321 static struct platform_driver at91_shdwc_driver = {
 322         .remove = __exit_p(at91_shdwc_remove),
 323         .driver = {
 324                 .name = "at91-shdwc",
 325                 .of_match_table = at91_shdwc_of_match,
 326         },
 327 };
 328 module_platform_driver_probe(at91_shdwc_driver, at91_shdwc_probe);
 329
 330 MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
 331 MODULE_DESCRIPTION("Atmel shutdown controller driver");
 332 MODULE_LICENSE("GPL v2");