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// SPDX-License-Identifier: GPL-2.0
/*
* StarFive Designware Mobile Storage Host Controller Driver
*
* Copyright (c) 2022 StarFive Technology Co., Ltd.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/mfd/syscon.h>
#include <linux/mmc/host.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"
#define ALL_INT_CLR 0x1ffff
#define MAX_DELAY_CHAIN 32
struct starfive_priv {
struct device *dev;
struct regmap *reg_syscon;
u32 syscon_offset;
u32 syscon_shift;
u32 syscon_mask;
};
static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
{
int ret;
unsigned int clock;
if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
ret = clk_set_rate(host->ciu_clk, clock);
if (ret)
dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
host->bus_hz = clk_get_rate(host->ciu_clk);
} else {
dev_dbg(host->dev, "Using the internal divider\n");
}
}
static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
u32 opcode)
{
static const int grade = MAX_DELAY_CHAIN;
struct dw_mci *host = slot->host;
struct starfive_priv *priv = host->priv;
int rise_point = -1, fall_point = -1;
int err, prev_err = 0;
int i;
bool found = 0;
u32 regval;
/*
* Use grade as the max delay chain, and use the rise_point and
* fall_point to ensure the best sampling point of a data input
* signals.
*/
for (i = 0; i < grade; i++) {
regval = i << priv->syscon_shift;
err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
priv->syscon_mask, regval);
if (err)
return err;
mci_writel(host, RINTSTS, ALL_INT_CLR);
err = mmc_send_tuning(slot->mmc, opcode, NULL);
if (!err)
found = 1;
if (i > 0) {
if (err && !prev_err)
fall_point = i - 1;
if (!err && prev_err)
rise_point = i;
}
if (rise_point != -1 && fall_point != -1)
goto tuning_out;
prev_err = err;
err = 0;
}
tuning_out:
if (found) {
if (rise_point == -1)
rise_point = 0;
if (fall_point == -1)
fall_point = grade - 1;
if (fall_point < rise_point) {
if ((rise_point + fall_point) >
(grade - 1))
i = fall_point / 2;
else
i = (rise_point + grade - 1) / 2;
} else {
i = (rise_point + fall_point) / 2;
}
regval = i << priv->syscon_shift;
err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
priv->syscon_mask, regval);
if (err)
return err;
mci_writel(host, RINTSTS, ALL_INT_CLR);
dev_info(host->dev, "Found valid delay chain! use it [delay=%d]\n", i);
} else {
dev_err(host->dev, "No valid delay chain! use default\n");
err = -EINVAL;
}
mci_writel(host, RINTSTS, ALL_INT_CLR);
return err;
}
static int dw_mci_starfive_parse_dt(struct dw_mci *host)
{
struct of_phandle_args args;
struct starfive_priv *priv;
int ret;
priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
ret = of_parse_phandle_with_fixed_args(host->dev->of_node,
"starfive,sysreg", 3, 0, &args);
if (ret) {
dev_err(host->dev, "Failed to parse starfive,sysreg\n");
return -EINVAL;
}
priv->reg_syscon = syscon_node_to_regmap(args.np);
of_node_put(args.np);
if (IS_ERR(priv->reg_syscon))
return PTR_ERR(priv->reg_syscon);
priv->syscon_offset = args.args[0];
priv->syscon_shift = args.args[1];
priv->syscon_mask = args.args[2];
host->priv = priv;
return 0;
}
static const struct dw_mci_drv_data starfive_data = {
.common_caps = MMC_CAP_CMD23,
.set_ios = dw_mci_starfive_set_ios,
.parse_dt = dw_mci_starfive_parse_dt,
.execute_tuning = dw_mci_starfive_execute_tuning,
};
static const struct of_device_id dw_mci_starfive_match[] = {
{ .compatible = "starfive,jh7110-mmc",
.data = &starfive_data },
{},
};
MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
static int dw_mci_starfive_probe(struct platform_device *pdev)
{
return dw_mci_pltfm_register(pdev, &starfive_data);
}
static struct platform_driver dw_mci_starfive_driver = {
.probe = dw_mci_starfive_probe,
.remove = dw_mci_pltfm_remove,
.driver = {
.name = "dwmmc_starfive",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
.of_match_table = dw_mci_starfive_match,
},
};
module_platform_driver(dw_mci_starfive_driver);
MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dwmmc_starfive");
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