drivers/mmc/host/sdhci-of-at91.c

   1 /*
   2  * Atmel SDMMC controller driver.
   3  *
   4  * Copyright (C) 2015 Atmel,
   5  *               2015 Ludovic Desroches <ludovic.desroches@atmel.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/clk.h>
  18 #include <linux/delay.h>
  19 #include <linux/err.h>
  20 #include <linux/io.h>
  21 #include <linux/kernel.h>
  22 #include <linux/mmc/host.h>
  23 #include <linux/mmc/slot-gpio.h>
  24 #include <linux/module.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27 #include <linux/pm.h>
  28 #include <linux/pm_runtime.h>
  29
  30 #include "sdhci-pltfm.h"
  31
  32 #define SDMMC_MC1R      0x204
  33 #define         SDMMC_MC1R_DDR          BIT(3)
  34 #define SDMMC_CACR      0x230
  35 #define         SDMMC_CACR_CAPWREN      BIT(0)
  36 #define         SDMMC_CACR_KEY          (0x46 << 8)
  37
  38 #define SDHCI_AT91_PRESET_COMMON_CONF   0x400 /* drv type B, programmable clock mode */
  39
  40 struct sdhci_at91_priv {
  41         struct clk *hclock;
  42         struct clk *gck;
  43         struct clk *mainck;
  44 };
  45
  46 static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock)
  47 {
  48         u16 clk;
  49         unsigned long timeout;
  50
  51         host->mmc->actual_clock = 0;
  52
  53         /*
  54          * There is no requirement to disable the internal clock before
  55          * changing the SD clock configuration. Moreover, disabling the
  56          * internal clock, changing the configuration and re-enabling the
  57          * internal clock causes some bugs. It can prevent to get the internal
  58          * clock stable flag ready and an unexpected switch to the base clock
  59          * when using presets.
  60          */
  61         clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
  62         clk &= SDHCI_CLOCK_INT_EN;
  63         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
  64
  65         if (clock == 0)
  66                 return;
  67
  68         clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock);
  69
  70         clk |= SDHCI_CLOCK_INT_EN;
  71         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
  72
  73         /* Wait max 20 ms */
  74         timeout = 20;
  75         while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
  76                 & SDHCI_CLOCK_INT_STABLE)) {
  77                 if (timeout == 0) {
  78                         pr_err("%s: Internal clock never stabilised.\n",
  79                                mmc_hostname(host->mmc));
  80                         return;
  81                 }
  82                 timeout--;
  83                 mdelay(1);
  84         }
  85
  86         clk |= SDHCI_CLOCK_CARD_EN;
  87         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
  88 }
  89
  90 /*
  91  * In this specific implementation of the SDHCI controller, the power register
  92  * needs to have a valid voltage set even when the power supply is managed by
  93  * an external regulator.
  94  */
  95 static void sdhci_at91_set_power(struct sdhci_host *host, unsigned char mode,
  96                      unsigned short vdd)
  97 {
  98         if (!IS_ERR(host->mmc->supply.vmmc)) {
  99                 struct mmc_host *mmc = host->mmc;
 100
 101                 mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
 102         }
 103         sdhci_set_power_noreg(host, mode, vdd);
 104 }
 105
 106 void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing)
 107 {
 108         if (timing == MMC_TIMING_MMC_DDR52)
 109                 sdhci_writeb(host, SDMMC_MC1R_DDR, SDMMC_MC1R);
 110         sdhci_set_uhs_signaling(host, timing);
 111 }
 112
 113 static const struct sdhci_ops sdhci_at91_sama5d2_ops = {
 114         .set_clock              = sdhci_at91_set_clock,
 115         .set_bus_width          = sdhci_set_bus_width,
 116         .reset                  = sdhci_reset,
 117         .set_uhs_signaling      = sdhci_at91_set_uhs_signaling,
 118         .set_power              = sdhci_at91_set_power,
 119 };
 120
 121 static const struct sdhci_pltfm_data soc_data_sama5d2 = {
 122         .ops = &sdhci_at91_sama5d2_ops,
 123 };
 124
 125 static const struct of_device_id sdhci_at91_dt_match[] = {
 126         { .compatible = "atmel,sama5d2-sdhci", .data = &soc_data_sama5d2 },
 127         {}
 128 };
 129 MODULE_DEVICE_TABLE(of, sdhci_at91_dt_match);
 130
 131 #ifdef CONFIG_PM
 132 static int sdhci_at91_runtime_suspend(struct device *dev)
 133 {
 134         struct sdhci_host *host = dev_get_drvdata(dev);
 135         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 136         struct sdhci_at91_priv *priv = sdhci_pltfm_priv(pltfm_host);
 137         int ret;
 138
 139         ret = sdhci_runtime_suspend_host(host);
 140
 141         if (host->tuning_mode != SDHCI_TUNING_MODE_3)
 142                 mmc_retune_needed(host->mmc);
 143
 144         clk_disable_unprepare(priv->gck);
 145         clk_disable_unprepare(priv->hclock);
 146         clk_disable_unprepare(priv->mainck);
 147
 148         return ret;
 149 }
 150
 151 static int sdhci_at91_runtime_resume(struct device *dev)
 152 {
 153         struct sdhci_host *host = dev_get_drvdata(dev);
 154         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 155         struct sdhci_at91_priv *priv = sdhci_pltfm_priv(pltfm_host);
 156         int ret;
 157
 158         ret = clk_prepare_enable(priv->mainck);
 159         if (ret) {
 160                 dev_err(dev, "can't enable mainck\n");
 161                 return ret;
 162         }
 163
 164         ret = clk_prepare_enable(priv->hclock);
 165         if (ret) {
 166                 dev_err(dev, "can't enable hclock\n");
 167                 return ret;
 168         }
 169
 170         ret = clk_prepare_enable(priv->gck);
 171         if (ret) {
 172                 dev_err(dev, "can't enable gck\n");
 173                 return ret;
 174         }
 175
 176         return sdhci_runtime_resume_host(host);
 177 }
 178 #endif /* CONFIG_PM */
 179
 180 static const struct dev_pm_ops sdhci_at91_dev_pm_ops = {
 181         SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
 182                                 pm_runtime_force_resume)
 183         SET_RUNTIME_PM_OPS(sdhci_at91_runtime_suspend,
 184                            sdhci_at91_runtime_resume,
 185                            NULL)
 186 };
 187
 188 static int sdhci_at91_probe(struct platform_device *pdev)
 189 {
 190         const struct of_device_id       *match;
 191         const struct sdhci_pltfm_data   *soc_data;
 192         struct sdhci_host               *host;
 193         struct sdhci_pltfm_host         *pltfm_host;
 194         struct sdhci_at91_priv          *priv;
 195         unsigned int                    caps0, caps1;
 196         unsigned int                    clk_base, clk_mul;
 197         unsigned int                    gck_rate, real_gck_rate;
 198         int                             ret;
 199         unsigned int                    preset_div;
 200
 201         match = of_match_device(sdhci_at91_dt_match, &pdev->dev);
 202         if (!match)
 203                 return -EINVAL;
 204         soc_data = match->data;
 205
 206         host = sdhci_pltfm_init(pdev, soc_data, sizeof(*priv));
 207         if (IS_ERR(host))
 208                 return PTR_ERR(host);
 209
 210         pltfm_host = sdhci_priv(host);
 211         priv = sdhci_pltfm_priv(pltfm_host);
 212
 213         priv->mainck = devm_clk_get(&pdev->dev, "baseclk");
 214         if (IS_ERR(priv->mainck)) {
 215                 dev_err(&pdev->dev, "failed to get baseclk\n");
 216                 return PTR_ERR(priv->mainck);
 217         }
 218
 219         priv->hclock = devm_clk_get(&pdev->dev, "hclock");
 220         if (IS_ERR(priv->hclock)) {
 221                 dev_err(&pdev->dev, "failed to get hclock\n");
 222                 return PTR_ERR(priv->hclock);
 223         }
 224
 225         priv->gck = devm_clk_get(&pdev->dev, "multclk");
 226         if (IS_ERR(priv->gck)) {
 227                 dev_err(&pdev->dev, "failed to get multclk\n");
 228                 return PTR_ERR(priv->gck);
 229         }
 230
 231         /*
 232          * The mult clock is provided by as a generated clock by the PMC
 233          * controller. In order to set the rate of gck, we have to get the
 234          * base clock rate and the clock mult from capabilities.
 235          */
 236         clk_prepare_enable(priv->hclock);
 237         caps0 = readl(host->ioaddr + SDHCI_CAPABILITIES);
 238         caps1 = readl(host->ioaddr + SDHCI_CAPABILITIES_1);
 239         clk_base = (caps0 & SDHCI_CLOCK_V3_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT;
 240         clk_mul = (caps1 & SDHCI_CLOCK_MUL_MASK) >> SDHCI_CLOCK_MUL_SHIFT;
 241         gck_rate = clk_base * 1000000 * (clk_mul + 1);
 242         ret = clk_set_rate(priv->gck, gck_rate);
 243         if (ret < 0) {
 244                 dev_err(&pdev->dev, "failed to set gck");
 245                 goto hclock_disable_unprepare;
 246         }
 247         /*
 248          * We need to check if we have the requested rate for gck because in
 249          * some cases this rate could be not supported. If it happens, the rate
 250          * is the closest one gck can provide. We have to update the value
 251          * of clk mul.
 252          */
 253         real_gck_rate = clk_get_rate(priv->gck);
 254         if (real_gck_rate != gck_rate) {
 255                 clk_mul = real_gck_rate / (clk_base * 1000000) - 1;
 256                 caps1 &= (~SDHCI_CLOCK_MUL_MASK);
 257                 caps1 |= ((clk_mul << SDHCI_CLOCK_MUL_SHIFT) & SDHCI_CLOCK_MUL_MASK);
 258                 /* Set capabilities in r/w mode. */
 259                 writel(SDMMC_CACR_KEY | SDMMC_CACR_CAPWREN, host->ioaddr + SDMMC_CACR);
 260                 writel(caps1, host->ioaddr + SDHCI_CAPABILITIES_1);
 261                 /* Set capabilities in ro mode. */
 262                 writel(0, host->ioaddr + SDMMC_CACR);
 263                 dev_info(&pdev->dev, "update clk mul to %u as gck rate is %u Hz\n",
 264                          clk_mul, real_gck_rate);
 265         }
 266
 267         /*
 268          * We have to set preset values because it depends on the clk_mul
 269          * value. Moreover, SDR104 is supported in a degraded mode since the
 270          * maximum sd clock value is 120 MHz instead of 208 MHz. For that
 271          * reason, we need to use presets to support SDR104.
 272          */
 273         preset_div = DIV_ROUND_UP(real_gck_rate, 24000000) - 1;
 274         writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 275                host->ioaddr + SDHCI_PRESET_FOR_SDR12);
 276         preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
 277         writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 278                host->ioaddr + SDHCI_PRESET_FOR_SDR25);
 279         preset_div = DIV_ROUND_UP(real_gck_rate, 100000000) - 1;
 280         writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 281                host->ioaddr + SDHCI_PRESET_FOR_SDR50);
 282         preset_div = DIV_ROUND_UP(real_gck_rate, 120000000) - 1;
 283         writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 284                host->ioaddr + SDHCI_PRESET_FOR_SDR104);
 285         preset_div = DIV_ROUND_UP(real_gck_rate, 50000000) - 1;
 286         writew(SDHCI_AT91_PRESET_COMMON_CONF | preset_div,
 287                host->ioaddr + SDHCI_PRESET_FOR_DDR50);
 288
 289         clk_prepare_enable(priv->mainck);
 290         clk_prepare_enable(priv->gck);
 291
 292         ret = mmc_of_parse(host->mmc);
 293         if (ret)
 294                 goto clocks_disable_unprepare;
 295
 296         sdhci_get_of_property(pdev);
 297
 298         pm_runtime_get_noresume(&pdev->dev);
 299         pm_runtime_set_active(&pdev->dev);
 300         pm_runtime_enable(&pdev->dev);
 301         pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
 302         pm_runtime_use_autosuspend(&pdev->dev);
 303
 304         ret = sdhci_add_host(host);
 305         if (ret)
 306                 goto pm_runtime_disable;
 307
 308         /*
 309          * When calling sdhci_runtime_suspend_host(), the sdhci layer makes
 310          * the assumption that all the clocks of the controller are disabled.
 311          * It means we can't get irq from it when it is runtime suspended.
 312          * For that reason, it is not planned to wake-up on a card detect irq
 313          * from the controller.
 314          * If we want to use runtime PM and to be able to wake-up on card
 315          * insertion, we have to use a GPIO for the card detection or we can
 316          * use polling. Be aware that using polling will resume/suspend the
 317          * controller between each attempt.
 318          * Disable SDHCI_QUIRK_BROKEN_CARD_DETECTION to be sure nobody tries
 319          * to enable polling via device tree with broken-cd property.
 320          */
 321         if (mmc_card_is_removable(host->mmc) &&
 322             mmc_gpio_get_cd(host->mmc) < 0) {
 323                 host->mmc->caps |= MMC_CAP_NEEDS_POLL;
 324                 host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
 325         }
 326
 327         pm_runtime_put_autosuspend(&pdev->dev);
 328
 329         return 0;
 330
 331 pm_runtime_disable:
 332         pm_runtime_disable(&pdev->dev);
 333         pm_runtime_set_suspended(&pdev->dev);
 334         pm_runtime_put_noidle(&pdev->dev);
 335 clocks_disable_unprepare:
 336         clk_disable_unprepare(priv->gck);
 337         clk_disable_unprepare(priv->mainck);
 338 hclock_disable_unprepare:
 339         clk_disable_unprepare(priv->hclock);
 340         sdhci_pltfm_free(pdev);
 341         return ret;
 342 }
 343
 344 static int sdhci_at91_remove(struct platform_device *pdev)
 345 {
 346         struct sdhci_host       *host = platform_get_drvdata(pdev);
 347         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 348         struct sdhci_at91_priv  *priv = sdhci_pltfm_priv(pltfm_host);
 349         struct clk *gck = priv->gck;
 350         struct clk *hclock = priv->hclock;
 351         struct clk *mainck = priv->mainck;
 352
 353         pm_runtime_get_sync(&pdev->dev);
 354         pm_runtime_disable(&pdev->dev);
 355         pm_runtime_put_noidle(&pdev->dev);
 356
 357         sdhci_pltfm_unregister(pdev);
 358
 359         clk_disable_unprepare(gck);
 360         clk_disable_unprepare(hclock);
 361         clk_disable_unprepare(mainck);
 362
 363         return 0;
 364 }
 365
 366 static struct platform_driver sdhci_at91_driver = {
 367         .driver         = {
 368                 .name   = "sdhci-at91",
 369                 .of_match_table = sdhci_at91_dt_match,
 370                 .pm     = &sdhci_at91_dev_pm_ops,
 371         },
 372         .probe          = sdhci_at91_probe,
 373         .remove         = sdhci_at91_remove,
 374 };
 375
 376 module_platform_driver(sdhci_at91_driver);
 377
 378 MODULE_DESCRIPTION("SDHCI driver for at91");
 379 MODULE_AUTHOR("Ludovic Desroches <ludovic.desroches@atmel.com>");
 380 MODULE_LICENSE("GPL v2");