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/bitfield.h>
   9 #include <linux/clk.h>
  10 #include <linux/delay.h>
  11 #include <linux/mfd/syscon.h>
  12 #include <linux/mmc/host.h>
  13 #include <linux/module.h>
  14 #include <linux/of_address.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/regmap.h>
  17
  18 #include "dw_mmc.h"
  19 #include "dw_mmc-pltfm.h"
  20
  21 #define ALL_INT_CLR             0x1ffff
  22 #define MAX_DELAY_CHAIN         32
  23
  24 #define STARFIVE_SMPL_PHASE     GENMASK(20, 16)
  25
  26 static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
  27 {
  28         int ret;
  29         unsigned int clock;
  30
  31         if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
  32                 clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
  33                 ret = clk_set_rate(host->ciu_clk, clock);
  34                 if (ret)
  35                         dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
  36                 host->bus_hz = clk_get_rate(host->ciu_clk);
  37         } else {
  38                 dev_dbg(host->dev, "Using the internal divider\n");
  39         }
  40 }
  41
  42 static void dw_mci_starfive_set_sample_phase(struct dw_mci *host, u32 smpl_phase)
  43 {
  44         /* change driver phase and sample phase */
  45         u32 reg_value = mci_readl(host, UHS_REG_EXT);
  46
  47         /* In UHS_REG_EXT, only 5 bits valid in DRV_PHASE and SMPL_PHASE */
  48         reg_value &= ~STARFIVE_SMPL_PHASE;
  49         reg_value |= FIELD_PREP(STARFIVE_SMPL_PHASE, smpl_phase);
  50         mci_writel(host, UHS_REG_EXT, reg_value);
  51
  52         /* We should delay 1ms wait for timing setting finished. */
  53         mdelay(1);
  54 }
  55
  56 static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
  57                                              u32 opcode)
  58 {
  59         static const int grade  = MAX_DELAY_CHAIN;
  60         struct dw_mci *host = slot->host;
  61         int smpl_phase, smpl_raise = -1, smpl_fall = -1;
  62         int ret;
  63
  64         for (smpl_phase = 0; smpl_phase < grade; smpl_phase++) {
  65                 dw_mci_starfive_set_sample_phase(host, smpl_phase);
  66                 mci_writel(host, RINTSTS, ALL_INT_CLR);
  67
  68                 ret = mmc_send_tuning(slot->mmc, opcode, NULL);
  69
  70                 if (!ret && smpl_raise < 0) {
  71                         smpl_raise = smpl_phase;
  72                 } else if (ret && smpl_raise >= 0) {
  73                         smpl_fall = smpl_phase - 1;
  74                         break;
  75                 }
  76         }
  77
  78         if (smpl_phase >= grade)
  79                 smpl_fall = grade - 1;
  80
  81         if (smpl_raise < 0) {
  82                 smpl_phase = 0;
  83                 dev_err(host->dev, "No valid delay chain! use default\n");
  84                 ret = -EINVAL;
  85                 goto out;
  86         }
  87
  88         smpl_phase = (smpl_raise + smpl_fall) / 2;
  89         dev_dbg(host->dev, "Found valid delay chain! use it [delay=%d]\n", smpl_phase);
  90         ret = 0;
  91
  92 out:
  93         dw_mci_starfive_set_sample_phase(host, smpl_phase);
  94         mci_writel(host, RINTSTS, ALL_INT_CLR);
  95         return ret;
  96 }
  97
  98 static const struct dw_mci_drv_data starfive_data = {
  99         .common_caps            = MMC_CAP_CMD23,
 100         .set_ios                = dw_mci_starfive_set_ios,
 101         .execute_tuning         = dw_mci_starfive_execute_tuning,
 102 };
 103
 104 static const struct of_device_id dw_mci_starfive_match[] = {
 105         { .compatible = "starfive,jh7110-mmc",
 106                 .data = &starfive_data },
 107         {},
 108 };
 109 MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
 110
 111 static int dw_mci_starfive_probe(struct platform_device *pdev)
 112 {
 113         return dw_mci_pltfm_register(pdev, &starfive_data);
 114 }
 115
 116 static struct platform_driver dw_mci_starfive_driver = {
 117         .probe = dw_mci_starfive_probe,
 118         .remove = dw_mci_pltfm_remove,
 119         .driver = {
 120                 .name = "dwmmc_starfive",
 121                 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
 122                 .of_match_table = dw_mci_starfive_match,
 123         },
 124 };
 125 module_platform_driver(dw_mci_starfive_driver);
 126
 127 MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
 128 MODULE_LICENSE("GPL");
 129 MODULE_ALIAS("platform:dwmmc_starfive");