drivers/mmc/host/sdhci-iproc.c

   1 /*
   2  * Copyright (C) 2014 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 /*
  15  * iProc SDHCI platform driver
  16  */
  17
  18 #include <linux/delay.h>
  19 #include <linux/module.h>
  20 #include <linux/mmc/host.h>
  21 #include <linux/of.h>
  22 #include <linux/of_device.h>
  23 #include "sdhci-pltfm.h"
  24
  25 struct sdhci_iproc_data {
  26         const struct sdhci_pltfm_data *pdata;
  27         u32 caps;
  28         u32 caps1;
  29         u32 mmc_caps;
  30 };
  31
  32 struct sdhci_iproc_host {
  33         const struct sdhci_iproc_data *data;
  34         u32 shadow_cmd;
  35         u32 shadow_blk;
  36 };
  37
  38 #define REG_OFFSET_IN_BITS(reg) ((reg) << 3 & 0x18)
  39
  40 static inline u32 sdhci_iproc_readl(struct sdhci_host *host, int reg)
  41 {
  42         u32 val = readl(host->ioaddr + reg);
  43
  44         pr_debug("%s: readl [0x%02x] 0x%08x\n",
  45                  mmc_hostname(host->mmc), reg, val);
  46         return val;
  47 }
  48
  49 static u16 sdhci_iproc_readw(struct sdhci_host *host, int reg)
  50 {
  51         u32 val = sdhci_iproc_readl(host, (reg & ~3));
  52         u16 word = val >> REG_OFFSET_IN_BITS(reg) & 0xffff;
  53         return word;
  54 }
  55
  56 static u8 sdhci_iproc_readb(struct sdhci_host *host, int reg)
  57 {
  58         u32 val = sdhci_iproc_readl(host, (reg & ~3));
  59         u8 byte = val >> REG_OFFSET_IN_BITS(reg) & 0xff;
  60         return byte;
  61 }
  62
  63 static inline void sdhci_iproc_writel(struct sdhci_host *host, u32 val, int reg)
  64 {
  65         pr_debug("%s: writel [0x%02x] 0x%08x\n",
  66                  mmc_hostname(host->mmc), reg, val);
  67
  68         writel(val, host->ioaddr + reg);
  69
  70         if (host->clock <= 400000) {
  71                 /* Round up to micro-second four SD clock delay */
  72                 if (host->clock)
  73                         udelay((4 * 1000000 + host->clock - 1) / host->clock);
  74                 else
  75                         udelay(10);
  76         }
  77 }
  78
  79 /*
  80  * The Arasan has a bugette whereby it may lose the content of successive
  81  * writes to the same register that are within two SD-card clock cycles of
  82  * each other (a clock domain crossing problem). The data
  83  * register does not have this problem, which is just as well - otherwise we'd
  84  * have to nobble the DMA engine too.
  85  *
  86  * This wouldn't be a problem with the code except that we can only write the
  87  * controller with 32-bit writes.  So two different 16-bit registers are
  88  * written back to back creates the problem.
  89  *
  90  * In reality, this only happens when SDHCI_BLOCK_SIZE and SDHCI_BLOCK_COUNT
  91  * are written followed by SDHCI_TRANSFER_MODE and SDHCI_COMMAND.
  92  * The BLOCK_SIZE and BLOCK_COUNT are meaningless until a command issued so
  93  * the work around can be further optimized. We can keep shadow values of
  94  * BLOCK_SIZE, BLOCK_COUNT, and TRANSFER_MODE until a COMMAND is issued.
  95  * Then, write the BLOCK_SIZE+BLOCK_COUNT in a single 32-bit write followed
  96  * by the TRANSFER+COMMAND in another 32-bit write.
  97  */
  98 static void sdhci_iproc_writew(struct sdhci_host *host, u16 val, int reg)
  99 {
 100         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 101         struct sdhci_iproc_host *iproc_host = sdhci_pltfm_priv(pltfm_host);
 102         u32 word_shift = REG_OFFSET_IN_BITS(reg);
 103         u32 mask = 0xffff << word_shift;
 104         u32 oldval, newval;
 105
 106         if (reg == SDHCI_COMMAND) {
 107                 /* Write the block now as we are issuing a command */
 108                 if (iproc_host->shadow_blk != 0) {
 109                         sdhci_iproc_writel(host, iproc_host->shadow_blk,
 110                                 SDHCI_BLOCK_SIZE);
 111                         iproc_host->shadow_blk = 0;
 112                 }
 113                 oldval = iproc_host->shadow_cmd;
 114         } else if (reg == SDHCI_BLOCK_SIZE || reg == SDHCI_BLOCK_COUNT) {
 115                 /* Block size and count are stored in shadow reg */
 116                 oldval = iproc_host->shadow_blk;
 117         } else {
 118                 /* Read reg, all other registers are not shadowed */
 119                 oldval = sdhci_iproc_readl(host, (reg & ~3));
 120         }
 121         newval = (oldval & ~mask) | (val << word_shift);
 122
 123         if (reg == SDHCI_TRANSFER_MODE) {
 124                 /* Save the transfer mode until the command is issued */
 125                 iproc_host->shadow_cmd = newval;
 126         } else if (reg == SDHCI_BLOCK_SIZE || reg == SDHCI_BLOCK_COUNT) {
 127                 /* Save the block info until the command is issued */
 128                 iproc_host->shadow_blk = newval;
 129         } else {
 130                 /* Command or other regular 32-bit write */
 131                 sdhci_iproc_writel(host, newval, reg & ~3);
 132         }
 133 }
 134
 135 static void sdhci_iproc_writeb(struct sdhci_host *host, u8 val, int reg)
 136 {
 137         u32 oldval = sdhci_iproc_readl(host, (reg & ~3));
 138         u32 byte_shift = REG_OFFSET_IN_BITS(reg);
 139         u32 mask = 0xff << byte_shift;
 140         u32 newval = (oldval & ~mask) | (val << byte_shift);
 141
 142         sdhci_iproc_writel(host, newval, reg & ~3);
 143 }
 144
 145 static const struct sdhci_ops sdhci_iproc_ops = {
 146         .read_l = sdhci_iproc_readl,
 147         .read_w = sdhci_iproc_readw,
 148         .read_b = sdhci_iproc_readb,
 149         .write_l = sdhci_iproc_writel,
 150         .write_w = sdhci_iproc_writew,
 151         .write_b = sdhci_iproc_writeb,
 152         .set_clock = sdhci_set_clock,
 153         .get_max_clock = sdhci_pltfm_clk_get_max_clock,
 154         .set_bus_width = sdhci_set_bus_width,
 155         .reset = sdhci_reset,
 156         .set_uhs_signaling = sdhci_set_uhs_signaling,
 157 };
 158
 159 static const struct sdhci_pltfm_data sdhci_iproc_pltfm_data = {
 160         .quirks = SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
 161         .quirks2 = SDHCI_QUIRK2_ACMD23_BROKEN,
 162         .ops = &sdhci_iproc_ops,
 163 };
 164
 165 static const struct sdhci_iproc_data iproc_data = {
 166         .pdata = &sdhci_iproc_pltfm_data,
 167         .caps = 0x05E90000,
 168         .caps1 = 0x00000064,
 169         .mmc_caps = MMC_CAP_1_8V_DDR,
 170 };
 171
 172 static const struct sdhci_pltfm_data sdhci_bcm2835_pltfm_data = {
 173         .quirks = SDHCI_QUIRK_BROKEN_CARD_DETECTION |
 174                   SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
 175                   SDHCI_QUIRK_MISSING_CAPS,
 176         .ops = &sdhci_iproc_ops,
 177 };
 178
 179 static const struct sdhci_iproc_data bcm2835_data = {
 180         .pdata = &sdhci_bcm2835_pltfm_data,
 181         .caps = SDHCI_CAN_VDD_330,
 182         .caps1 = 0x00000000,
 183         .mmc_caps = 0x00000000,
 184 };
 185
 186 static const struct of_device_id sdhci_iproc_of_match[] = {
 187         { .compatible = "brcm,bcm2835-sdhci", .data = &bcm2835_data },
 188         { .compatible = "brcm,sdhci-iproc-cygnus", .data = &iproc_data },
 189         { }
 190 };
 191 MODULE_DEVICE_TABLE(of, sdhci_iproc_of_match);
 192
 193 static int sdhci_iproc_probe(struct platform_device *pdev)
 194 {
 195         const struct of_device_id *match;
 196         const struct sdhci_iproc_data *iproc_data;
 197         struct sdhci_host *host;
 198         struct sdhci_iproc_host *iproc_host;
 199         struct sdhci_pltfm_host *pltfm_host;
 200         int ret;
 201
 202         match = of_match_device(sdhci_iproc_of_match, &pdev->dev);
 203         if (!match)
 204                 return -EINVAL;
 205         iproc_data = match->data;
 206
 207         host = sdhci_pltfm_init(pdev, iproc_data->pdata, sizeof(*iproc_host));
 208         if (IS_ERR(host))
 209                 return PTR_ERR(host);
 210
 211         pltfm_host = sdhci_priv(host);
 212         iproc_host = sdhci_pltfm_priv(pltfm_host);
 213
 214         iproc_host->data = iproc_data;
 215
 216         mmc_of_parse(host->mmc);
 217         sdhci_get_of_property(pdev);
 218
 219         host->mmc->caps |= iproc_host->data->mmc_caps;
 220
 221         pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
 222         if (IS_ERR(pltfm_host->clk)) {
 223                 ret = PTR_ERR(pltfm_host->clk);
 224                 goto err;
 225         }
 226         ret = clk_prepare_enable(pltfm_host->clk);
 227         if (ret) {
 228                 dev_err(&pdev->dev, "failed to enable host clk\n");
 229                 goto err;
 230         }
 231
 232         if (iproc_host->data->pdata->quirks & SDHCI_QUIRK_MISSING_CAPS) {
 233                 host->caps = iproc_host->data->caps;
 234                 host->caps1 = iproc_host->data->caps1;
 235         }
 236
 237         ret = sdhci_add_host(host);
 238         if (ret)
 239                 goto err_clk;
 240
 241         return 0;
 242
 243 err_clk:
 244         clk_disable_unprepare(pltfm_host->clk);
 245 err:
 246         sdhci_pltfm_free(pdev);
 247         return ret;
 248 }
 249
 250 static struct platform_driver sdhci_iproc_driver = {
 251         .driver = {
 252                 .name = "sdhci-iproc",
 253                 .of_match_table = sdhci_iproc_of_match,
 254                 .pm = SDHCI_PLTFM_PMOPS,
 255         },
 256         .probe = sdhci_iproc_probe,
 257         .remove = sdhci_pltfm_unregister,
 258 };
 259 module_platform_driver(sdhci_iproc_driver);
 260
 261 MODULE_AUTHOR("Broadcom");
 262 MODULE_DESCRIPTION("IPROC SDHCI driver");
 263 MODULE_LICENSE("GPL v2");