linux_kernel/drivers/mmc/host/sdhci-of-dwcmshc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for Synopsys DesignWare Cores Mobile Storage Host Controller
 *
 * Copyright (C) 2018 Synaptics Incorporated
 *
 * Author: Jisheng Zhang <jszhang@kernel.org>
 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/sizes.h>

#include "sdhci-pltfm.h"

#define BOUNDARY_OK(addr, len) \
	((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))

struct dwcmshc_priv {
	struct clk	*bus_clk;
};

/*
 * If DMA addr spans 128MB boundary, we split the DMA transfer into two
 * so that each DMA transfer doesn't exceed the boundary.
 */
static void dwcmshc_adma_write_desc(struct sdhci_host *host, void **desc,
				    dma_addr_t addr, int len, unsigned int cmd)
{
	int tmplen, offset;

	if (likely(!len || BOUNDARY_OK(addr, len))) {
		sdhci_adma_write_desc(host, desc, addr, len, cmd);
		return;
	}

	offset = addr & (SZ_128M - 1);
	tmplen = SZ_128M - offset;
	sdhci_adma_write_desc(host, desc, addr, tmplen, cmd);

	addr += tmplen;
	len -= tmplen;
	sdhci_adma_write_desc(host, desc, addr, len, cmd);
}

static const struct sdhci_ops sdhci_dwcmshc_ops = {
	.set_clock		= sdhci_set_clock,
	.set_bus_width		= sdhci_set_bus_width,
	.set_uhs_signaling	= sdhci_set_uhs_signaling,
	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
	.reset			= sdhci_reset,
	.adma_write_desc	= dwcmshc_adma_write_desc,
};

static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = {
	.ops = &sdhci_dwcmshc_ops,
	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
};

static int dwcmshc_probe(struct platform_device *pdev)
{
	struct sdhci_pltfm_host *pltfm_host;
	struct sdhci_host *host;
	struct dwcmshc_priv *priv;
	int err;
	u32 extra;

	host = sdhci_pltfm_init(pdev, &sdhci_dwcmshc_pdata,
				sizeof(struct dwcmshc_priv));
	if (IS_ERR(host))
		return PTR_ERR(host);

	/*
	 * extra adma table cnt for cross 128M boundary handling.
	 */
	extra = DIV_ROUND_UP_ULL(dma_get_required_mask(&pdev->dev), SZ_128M);
	if (extra > SDHCI_MAX_SEGS)
		extra = SDHCI_MAX_SEGS;
	host->adma_table_cnt += extra;

	pltfm_host = sdhci_priv(host);
	priv = sdhci_pltfm_priv(pltfm_host);

	pltfm_host->clk = devm_clk_get(&pdev->dev, "core");
	if (IS_ERR(pltfm_host->clk)) {
		err = PTR_ERR(pltfm_host->clk);
		dev_err(&pdev->dev, "failed to get core clk: %d\n", err);
		goto free_pltfm;
	}
	err = clk_prepare_enable(pltfm_host->clk);
	if (err)
		goto free_pltfm;

	priv->bus_clk = devm_clk_get(&pdev->dev, "bus");
	if (!IS_ERR(priv->bus_clk))
		clk_prepare_enable(priv->bus_clk);

	err = mmc_of_parse(host->mmc);
	if (err)
		goto err_clk;

	sdhci_get_of_property(pdev);

	err = sdhci_add_host(host);
	if (err)
		goto err_clk;

	return 0;

err_clk:
	clk_disable_unprepare(pltfm_host->clk);
	clk_disable_unprepare(priv->bus_clk);
free_pltfm:
	sdhci_pltfm_free(pdev);
	return err;
}

static int dwcmshc_remove(struct platform_device *pdev)
{
	struct sdhci_host *host = platform_get_drvdata(pdev);
	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
	struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);

	sdhci_remove_host(host, 0);

	clk_disable_unprepare(pltfm_host->clk);
	clk_disable_unprepare(priv->bus_clk);

	sdhci_pltfm_free(pdev);

	return 0;
}

static const struct of_device_id sdhci_dwcmshc_dt_ids[] = {
	{ .compatible = "snps,dwcmshc-sdhci" },
	{}
};
MODULE_DEVICE_TABLE(of, sdhci_dwcmshc_dt_ids);

static struct platform_driver sdhci_dwcmshc_driver = {
	.driver	= {
		.name	= "sdhci-dwcmshc",
		.of_match_table = sdhci_dwcmshc_dt_ids,
	},
	.probe	= dwcmshc_probe,
	.remove	= dwcmshc_remove,
};
module_platform_driver(sdhci_dwcmshc_driver);

MODULE_DESCRIPTION("SDHCI platform driver for Synopsys DWC MSHC");
MODULE_AUTHOR("Jisheng Zhang <jszhang@kernel.org>");
MODULE_LICENSE("GPL v2");