linux/drivers/mmc/host/sdhci-of-dwcmshc.c
Jisheng Zhang b85c997d2c mmc: sdhci-of-dwcmshc: solve 128MB DMA boundary limitation
When using DMA, if the DMA addr spans 128MB boundary, we have to split
the DMA transfer into two so that each one doesn't exceed the boundary.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
2018-10-08 11:40:43 +02:00

156 lines
3.7 KiB
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");