bcmstb_sdhci.c
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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2018 Cisco Systems, Inc.
* (C) Copyright 2019 Synamedia
*
* Author: Thomas Fitzsimmons <fitzsim@fitzsim.org>
*/
#include <common.h>
#include <dm.h>
#include <mach/sdhci.h>
#include <malloc.h>
#include <sdhci.h>
/*
* The BCMSTB SDHCI has a quirk in that its actual maximum frequency
* capability is 100 MHz. The divisor that is eventually written to
* SDHCI_CLOCK_CONTROL is calculated based on what the MMC device
* reports, and relative to this maximum frequency.
*
* This define used to be set to 52000000 (52 MHz), the desired
* maximum frequency, but that would result in the communication
* actually running at 100 MHz (seemingly without issue), which is
* out-of-spec.
*
* Now, by setting this to 0 (auto-detect), 100 MHz will be read from
* the capabilities register, and the resulting divisor will be
* doubled, meaning that the clock control register will be set to the
* in-spec 52 MHz value.
*/
#define BCMSTB_SDHCI_MAXIMUM_CLOCK_FREQUENCY 0
/*
* When the minimum clock frequency is set to 0 (auto-detect), U-Boot
* sets it to 100 MHz divided by SDHCI_MAX_DIV_SPEC_300, or 48,875 Hz,
* which results in the controller timing out when trying to
* communicate with the MMC device. Hard-code this value to 400000
* (400 kHz) to prevent this.
*/
#define BCMSTB_SDHCI_MINIMUM_CLOCK_FREQUENCY 400000
/*
* This driver has only been tested with eMMC devices; SD devices may
* not work.
*/
struct sdhci_bcmstb_plat {
struct mmc_config cfg;
struct mmc mmc;
};
static int sdhci_bcmstb_bind(struct udevice *dev)
{
struct sdhci_bcmstb_plat *plat = dev_get_platdata(dev);
return sdhci_bind(dev, &plat->mmc, &plat->cfg);
}
static int sdhci_bcmstb_probe(struct udevice *dev)
{
struct mmc_uclass_priv *upriv = dev_get_uclass_priv(dev);
struct sdhci_bcmstb_plat *plat = dev_get_platdata(dev);
struct sdhci_host *host = dev_get_priv(dev);
fdt_addr_t base;
int ret;
base = devfdt_get_addr(dev);
if (base == FDT_ADDR_T_NONE)
return -EINVAL;
host->name = dev->name;
host->ioaddr = (void *)base;
ret = mmc_of_parse(dev, &plat->cfg);
if (ret)
return ret;
host->mmc = &plat->mmc;
host->mmc->dev = dev;
ret = sdhci_setup_cfg(&plat->cfg, host,
BCMSTB_SDHCI_MAXIMUM_CLOCK_FREQUENCY,
BCMSTB_SDHCI_MINIMUM_CLOCK_FREQUENCY);
if (ret)
return ret;
upriv->mmc = &plat->mmc;
host->mmc->priv = host;
return sdhci_probe(dev);
}
static const struct udevice_id sdhci_bcmstb_match[] = {
{ .compatible = "brcm,bcm7425-sdhci" },
{ .compatible = "brcm,sdhci-brcmstb" },
{ }
};
U_BOOT_DRIVER(sdhci_bcmstb) = {
.name = "sdhci-bcmstb",
.id = UCLASS_MMC,
.of_match = sdhci_bcmstb_match,
.ops = &sdhci_ops,
.bind = sdhci_bcmstb_bind,
.probe = sdhci_bcmstb_probe,
.priv_auto_alloc_size = sizeof(struct sdhci_host),
.platdata_auto_alloc_size = sizeof(struct sdhci_bcmstb_plat),
};