drivers/mmc/host/sdhci-bcm-kona.c

   1 /*
   2  * Copyright (C) 2013 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/delay.h>
  17 #include <linux/highmem.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/mmc/host.h>
  20 #include <linux/io.h>
  21 #include <linux/gpio.h>
  22 #include <linux/clk.h>
  23 #include <linux/regulator/consumer.h>
  24 #include <linux/of.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_gpio.h>
  27 #include <linux/mmc/slot-gpio.h>
  28
  29 #include "sdhci-pltfm.h"
  30 #include "sdhci.h"
  31
  32 #define SDHCI_SOFT_RESET                        0x01000000
  33 #define KONA_SDHOST_CORECTRL                    0x8000
  34 #define KONA_SDHOST_CD_PINCTRL                  0x00000008
  35 #define KONA_SDHOST_STOP_HCLK                   0x00000004
  36 #define KONA_SDHOST_RESET                       0x00000002
  37 #define KONA_SDHOST_EN                          0x00000001
  38
  39 #define KONA_SDHOST_CORESTAT                    0x8004
  40 #define KONA_SDHOST_WP                          0x00000002
  41 #define KONA_SDHOST_CD_SW                       0x00000001
  42
  43 #define KONA_SDHOST_COREIMR                     0x8008
  44 #define KONA_SDHOST_IP                          0x00000001
  45
  46 #define KONA_SDHOST_COREISR                     0x800C
  47 #define KONA_SDHOST_COREIMSR                    0x8010
  48 #define KONA_SDHOST_COREDBG1                    0x8014
  49 #define KONA_SDHOST_COREGPO_MASK                0x8018
  50
  51 #define SD_DETECT_GPIO_DEBOUNCE_128MS           128
  52
  53 #define KONA_MMC_AUTOSUSPEND_DELAY              (50)
  54
  55 struct sdhci_bcm_kona_dev {
  56         struct mutex    write_lock; /* protect back to back writes */
  57 };
  58
  59
  60 static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
  61 {
  62         unsigned int val;
  63         unsigned long timeout;
  64
  65         /* This timeout should be sufficent for core to reset */
  66         timeout = jiffies + msecs_to_jiffies(100);
  67
  68         /* reset the host using the top level reset */
  69         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
  70         val |= KONA_SDHOST_RESET;
  71         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
  72
  73         while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
  74                 if (time_is_before_jiffies(timeout)) {
  75                         pr_err("Error: sd host is stuck in reset!!!\n");
  76                         return -EFAULT;
  77                 }
  78         }
  79
  80         /* bring the host out of reset */
  81         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
  82         val &= ~KONA_SDHOST_RESET;
  83
  84         /*
  85          * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
  86          * Back-to-Back writes to same register needs delay when SD bus clock
  87          * is very low w.r.t AHB clock, mainly during boot-time and during card
  88          * insert-removal.
  89          */
  90         usleep_range(1000, 5000);
  91         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
  92
  93         return 0;
  94 }
  95
  96 static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
  97 {
  98         unsigned int val;
  99
 100         /* enable the interrupt from the IP core */
 101         val = sdhci_readl(host, KONA_SDHOST_COREIMR);
 102         val |= KONA_SDHOST_IP;
 103         sdhci_writel(host, val, KONA_SDHOST_COREIMR);
 104
 105         /* Enable the AHB clock gating module to the host */
 106         val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
 107         val |= KONA_SDHOST_EN;
 108
 109         /*
 110          * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
 111          * Back-to-Back writes to same register needs delay when SD bus clock
 112          * is very low w.r.t AHB clock, mainly during boot-time and during card
 113          * insert-removal.
 114          */
 115         usleep_range(1000, 5000);
 116         sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
 117 }
 118
 119 /*
 120  * Software emulation of the SD card insertion/removal. Set insert=1 for insert
 121  * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
 122  * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
 123  * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
 124  */
 125 static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
 126 {
 127         struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
 128         struct sdhci_bcm_kona_dev *kona_dev = sdhci_pltfm_priv(pltfm_priv);
 129         u32 val;
 130
 131         /*
 132          * Back-to-Back register write needs a delay of min 10uS.
 133          * Back-to-Back writes to same register needs delay when SD bus clock
 134          * is very low w.r.t AHB clock, mainly during boot-time and during card
 135          * insert-removal.
 136          * We keep 20uS
 137          */
 138         mutex_lock(&kona_dev->write_lock);
 139         udelay(20);
 140         val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
 141
 142         if (insert) {
 143                 int ret;
 144
 145                 ret = mmc_gpio_get_ro(host->mmc);
 146                 if (ret >= 0)
 147                         val = (val & ~KONA_SDHOST_WP) |
 148                                 ((ret) ? KONA_SDHOST_WP : 0);
 149
 150                 val |= KONA_SDHOST_CD_SW;
 151                 sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
 152         } else {
 153                 val &= ~KONA_SDHOST_CD_SW;
 154                 sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
 155         }
 156         mutex_unlock(&kona_dev->write_lock);
 157
 158         return 0;
 159 }
 160
 161 /*
 162  * SD card interrupt event callback
 163  */
 164 static void sdhci_bcm_kona_card_event(struct sdhci_host *host)
 165 {
 166         if (mmc_gpio_get_cd(host->mmc) > 0) {
 167                 dev_dbg(mmc_dev(host->mmc),
 168                         "card inserted\n");
 169                 sdhci_bcm_kona_sd_card_emulate(host, 1);
 170         } else {
 171                 dev_dbg(mmc_dev(host->mmc),
 172                         "card removed\n");
 173                 sdhci_bcm_kona_sd_card_emulate(host, 0);
 174         }
 175 }
 176
 177 static void sdhci_bcm_kona_init_74_clocks(struct sdhci_host *host,
 178                                 u8 power_mode)
 179 {
 180         /*
 181          *  JEDEC and SD spec specify supplying 74 continuous clocks to
 182          * device after power up. With minimum bus (100KHz) that
 183          * that translates to 740us
 184          */
 185         if (power_mode != MMC_POWER_OFF)
 186                 udelay(740);
 187 }
 188
 189 static struct sdhci_ops sdhci_bcm_kona_ops = {
 190         .set_clock = sdhci_set_clock,
 191         .get_max_clock = sdhci_pltfm_clk_get_max_clock,
 192         .get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
 193         .platform_send_init_74_clocks = sdhci_bcm_kona_init_74_clocks,
 194         .set_bus_width = sdhci_set_bus_width,
 195         .reset = sdhci_reset,
 196         .set_uhs_signaling = sdhci_set_uhs_signaling,
 197         .card_event = sdhci_bcm_kona_card_event,
 198 };
 199
 200 static struct sdhci_pltfm_data sdhci_pltfm_data_kona = {
 201         .ops    = &sdhci_bcm_kona_ops,
 202         .quirks = SDHCI_QUIRK_NO_CARD_NO_RESET |
 203                 SDHCI_QUIRK_BROKEN_TIMEOUT_VAL | SDHCI_QUIRK_32BIT_DMA_ADDR |
 204                 SDHCI_QUIRK_32BIT_DMA_SIZE | SDHCI_QUIRK_32BIT_ADMA_SIZE |
 205                 SDHCI_QUIRK_FORCE_BLK_SZ_2048 |
 206                 SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
 207 };
 208
 209 static const struct of_device_id sdhci_bcm_kona_of_match[] = {
 210         { .compatible = "brcm,kona-sdhci"},
 211         { .compatible = "bcm,kona-sdhci"}, /* deprecated name */
 212         {}
 213 };
 214 MODULE_DEVICE_TABLE(of, sdhci_bcm_kona_of_match);
 215
 216 static int sdhci_bcm_kona_probe(struct platform_device *pdev)
 217 {
 218         struct sdhci_bcm_kona_dev *kona_dev = NULL;
 219         struct sdhci_pltfm_host *pltfm_priv;
 220         struct device *dev = &pdev->dev;
 221         struct sdhci_host *host;
 222         int ret;
 223
 224         ret = 0;
 225
 226         host = sdhci_pltfm_init(pdev, &sdhci_pltfm_data_kona,
 227                         sizeof(*kona_dev));
 228         if (IS_ERR(host))
 229                 return PTR_ERR(host);
 230
 231         dev_dbg(dev, "%s: inited. IOADDR=%p\n", __func__, host->ioaddr);
 232
 233         pltfm_priv = sdhci_priv(host);
 234
 235         kona_dev = sdhci_pltfm_priv(pltfm_priv);
 236         mutex_init(&kona_dev->write_lock);
 237
 238         ret = mmc_of_parse(host->mmc);
 239         if (ret)
 240                 goto err_pltfm_free;
 241
 242         if (!host->mmc->f_max) {
 243                 dev_err(&pdev->dev, "Missing max-freq for SDHCI cfg\n");
 244                 ret = -ENXIO;
 245                 goto err_pltfm_free;
 246         }
 247
 248         /* Get and enable the core clock */
 249         pltfm_priv->clk = devm_clk_get(dev, NULL);
 250         if (IS_ERR(pltfm_priv->clk)) {
 251                 dev_err(dev, "Failed to get core clock\n");
 252                 ret = PTR_ERR(pltfm_priv->clk);
 253                 goto err_pltfm_free;
 254         }
 255
 256         if (clk_set_rate(pltfm_priv->clk, host->mmc->f_max) != 0) {
 257                 dev_err(dev, "Failed to set rate core clock\n");
 258                 goto err_pltfm_free;
 259         }
 260
 261         if (clk_prepare_enable(pltfm_priv->clk) != 0) {
 262                 dev_err(dev, "Failed to enable core clock\n");
 263                 goto err_pltfm_free;
 264         }
 265
 266         dev_dbg(dev, "non-removable=%c\n",
 267                 (host->mmc->caps & MMC_CAP_NONREMOVABLE) ? 'Y' : 'N');
 268         dev_dbg(dev, "cd_gpio %c, wp_gpio %c\n",
 269                 (mmc_gpio_get_cd(host->mmc) != -ENOSYS) ? 'Y' : 'N',
 270                 (mmc_gpio_get_ro(host->mmc) != -ENOSYS) ? 'Y' : 'N');
 271
 272         if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
 273                 host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
 274
 275         dev_dbg(dev, "is_8bit=%c\n",
 276                 (host->mmc->caps | MMC_CAP_8_BIT_DATA) ? 'Y' : 'N');
 277
 278         ret = sdhci_bcm_kona_sd_reset(host);
 279         if (ret)
 280                 goto err_clk_disable;
 281
 282         sdhci_bcm_kona_sd_init(host);
 283
 284         ret = sdhci_add_host(host);
 285         if (ret) {
 286                 dev_err(dev, "Failed sdhci_add_host\n");
 287                 goto err_reset;
 288         }
 289
 290         /* if device is eMMC, emulate card insert right here */
 291         if (host->mmc->caps & MMC_CAP_NONREMOVABLE) {
 292                 ret = sdhci_bcm_kona_sd_card_emulate(host, 1);
 293                 if (ret) {
 294                         dev_err(dev,
 295                                 "unable to emulate card insertion\n");
 296                         goto err_remove_host;
 297                 }
 298         }
 299         /*
 300          * Since the card detection GPIO interrupt is configured to be
 301          * edge sensitive, check the initial GPIO value here, emulate
 302          * only if the card is present
 303          */
 304         if (mmc_gpio_get_cd(host->mmc) > 0)
 305                 sdhci_bcm_kona_sd_card_emulate(host, 1);
 306
 307         dev_dbg(dev, "initialized properly\n");
 308         return 0;
 309
 310 err_remove_host:
 311         sdhci_remove_host(host, 0);
 312
 313 err_reset:
 314         sdhci_bcm_kona_sd_reset(host);
 315
 316 err_clk_disable:
 317         clk_disable_unprepare(pltfm_priv->clk);
 318
 319 err_pltfm_free:
 320         sdhci_pltfm_free(pdev);
 321
 322         dev_err(dev, "Probing of sdhci-pltfm failed: %d\n", ret);
 323         return ret;
 324 }
 325
 326 static struct platform_driver sdhci_bcm_kona_driver = {
 327         .driver         = {
 328                 .name   = "sdhci-kona",
 329                 .pm     = SDHCI_PLTFM_PMOPS,
 330                 .of_match_table = sdhci_bcm_kona_of_match,
 331         },
 332         .probe          = sdhci_bcm_kona_probe,
 333         .remove         = sdhci_pltfm_unregister,
 334 };
 335 module_platform_driver(sdhci_bcm_kona_driver);
 336
 337 MODULE_DESCRIPTION("SDHCI driver for Broadcom Kona platform");
 338 MODULE_AUTHOR("Broadcom");
 339 MODULE_LICENSE("GPL v2");