drivers/mmc/host/dw_mmc-starfive.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * StarFive Designware Mobile Storage Host Controller Driver
   4  *
   5  * Copyright (c) 2022 StarFive Technology Co., Ltd.
   6  */
   7
   8 #include <linux/clk.h>
   9 #include <linux/delay.h>
  10 #include <linux/mfd/syscon.h>
  11 #include <linux/mmc/host.h>
  12 #include <linux/module.h>
  13 #include <linux/of_address.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/regmap.h>
  16
  17 #include "dw_mmc.h"
  18 #include "dw_mmc-pltfm.h"
  19
  20 #define ALL_INT_CLR             0x1ffff
  21 #define MAX_DELAY_CHAIN         32
  22
  23 struct starfive_priv {
  24         struct device *dev;
  25         struct regmap *reg_syscon;
  26         u32 syscon_offset;
  27         u32 syscon_shift;
  28         u32 syscon_mask;
  29 };
  30
  31 static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  32 {
  33         int ret;
  34         unsigned int clock;
  35
  36         if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
  37                 clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
  38                 ret = clk_set_rate(host->ciu_clk, clock);
  39                 if (ret)
  40                         dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
  41                 host->bus_hz = clk_get_rate(host->ciu_clk);
  42         } else {
  43                 dev_dbg(host->dev, "Using the internal divider\n");
  44         }
  45 }
  46
  47 static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
  48                                              u32 opcode)
  49 {
  50         static const int grade  = MAX_DELAY_CHAIN;
  51         struct dw_mci *host = slot->host;
  52         struct starfive_priv *priv = host->priv;
  53         int rise_point = -1, fall_point = -1;
  54         int err, prev_err = 0;
  55         int i;
  56         bool found = 0;
  57         u32 regval;
  58
  59         /*
  60          * Use grade as the max delay chain, and use the rise_point and
  61          * fall_point to ensure the best sampling point of a data input
  62          * signals.
  63          */
  64         for (i = 0; i < grade; i++) {
  65                 regval = i << priv->syscon_shift;
  66                 err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
  67                                                 priv->syscon_mask, regval);
  68                 if (err)
  69                         return err;
  70                 mci_writel(host, RINTSTS, ALL_INT_CLR);
  71
  72                 err = mmc_send_tuning(slot->mmc, opcode, NULL);
  73                 if (!err)
  74                         found = 1;
  75
  76                 if (i > 0) {
  77                         if (err && !prev_err)
  78                                 fall_point = i - 1;
  79                         if (!err && prev_err)
  80                                 rise_point = i;
  81                 }
  82
  83                 if (rise_point != -1 && fall_point != -1)
  84                         goto tuning_out;
  85
  86                 prev_err = err;
  87                 err = 0;
  88         }
  89
  90 tuning_out:
  91         if (found) {
  92                 if (rise_point == -1)
  93                         rise_point = 0;
  94                 if (fall_point == -1)
  95                         fall_point = grade - 1;
  96                 if (fall_point < rise_point) {
  97                         if ((rise_point + fall_point) >
  98                             (grade - 1))
  99                                 i = fall_point / 2;
 100                         else
 101                                 i = (rise_point + grade - 1) / 2;
 102                 } else {
 103                         i = (rise_point + fall_point) / 2;
 104                 }
 105
 106                 regval = i << priv->syscon_shift;
 107                 err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
 108                                                 priv->syscon_mask, regval);
 109                 if (err)
 110                         return err;
 111                 mci_writel(host, RINTSTS, ALL_INT_CLR);
 112
 113                 dev_info(host->dev, "Found valid delay chain! use it [delay=%d]\n", i);
 114         } else {
 115                 dev_err(host->dev, "No valid delay chain! use default\n");
 116                 err = -EINVAL;
 117         }
 118
 119         mci_writel(host, RINTSTS, ALL_INT_CLR);
 120         return err;
 121 }
 122
 123 static int dw_mci_starfive_parse_dt(struct dw_mci *host)
 124 {
 125         struct of_phandle_args args;
 126         struct starfive_priv *priv;
 127         int ret;
 128
 129         priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
 130         if (!priv)
 131                 return -ENOMEM;
 132
 133         ret = of_parse_phandle_with_fixed_args(host->dev->of_node,
 134                                                 "starfive,sysreg", 3, 0, &args);
 135         if (ret) {
 136                 dev_err(host->dev, "Failed to parse starfive,sysreg\n");
 137                 return -EINVAL;
 138         }
 139
 140         priv->reg_syscon = syscon_node_to_regmap(args.np);
 141         of_node_put(args.np);
 142         if (IS_ERR(priv->reg_syscon))
 143                 return PTR_ERR(priv->reg_syscon);
 144
 145         priv->syscon_offset = args.args[0];
 146         priv->syscon_shift  = args.args[1];
 147         priv->syscon_mask   = args.args[2];
 148
 149         host->priv = priv;
 150
 151         return 0;
 152 }
 153
 154 static const struct dw_mci_drv_data starfive_data = {
 155         .common_caps            = MMC_CAP_CMD23,
 156         .set_ios                = dw_mci_starfive_set_ios,
 157         .parse_dt               = dw_mci_starfive_parse_dt,
 158         .execute_tuning         = dw_mci_starfive_execute_tuning,
 159 };
 160
 161 static const struct of_device_id dw_mci_starfive_match[] = {
 162         { .compatible = "starfive,jh7110-mmc",
 163                 .data = &starfive_data },
 164         {},
 165 };
 166 MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
 167
 168 static int dw_mci_starfive_probe(struct platform_device *pdev)
 169 {
 170         return dw_mci_pltfm_register(pdev, &starfive_data);
 171 }
 172
 173 static struct platform_driver dw_mci_starfive_driver = {
 174         .probe = dw_mci_starfive_probe,
 175         .remove_new = dw_mci_pltfm_remove,
 176         .driver = {
 177                 .name = "dwmmc_starfive",
 178                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 179                 .of_match_table = dw_mci_starfive_match,
 180         },
 181 };
 182 module_platform_driver(dw_mci_starfive_driver);
 183
 184 MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
 185 MODULE_LICENSE("GPL");
 186 MODULE_ALIAS("platform:dwmmc_starfive");