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