Re: [PATCH 6/10] mmc: sdhci-xenon: Add Marvell Xenon SDHC core functionality

From: Ulf Hansson
Date: Thu Nov 24 2016 - 05:44:29 EST


On 31 October 2016 at 12:09, Gregory CLEMENT
<gregory.clement@xxxxxxxxxxxxxxxxxx> wrote:
> From: Ziji Hu <huziji@xxxxxxxxxxx>
>
> Add Xenon eMMC/SD/SDIO host controller core functionality.
> Add Xenon specific intialization process.
> Add Xenon specific mmc_host_ops APIs.
> Add Xenon specific register definitions.
>
> Add CONFIG_MMC_SDHCI_XENON support in drivers/mmc/host/Kconfig.
>
> Marvell Xenon SDHC conforms to SD Physical Layer Specification
> Version 3.01 and is designed according to the guidelines provided
> in the SD Host Controller Standard Specification Version 3.00.
>
> Signed-off-by: Hu Ziji <huziji@xxxxxxxxxxx>
> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> ---
> MAINTAINERS | 1 +-
> drivers/mmc/host/Kconfig | 9 +-
> drivers/mmc/host/Makefile | 3 +-
> drivers/mmc/host/sdhci-xenon.c | 594 ++++++++++++++++++++++++++++++++++-
> drivers/mmc/host/sdhci-xenon.h | 142 ++++++++-
> 5 files changed, 749 insertions(+), 0 deletions(-)
> create mode 100644 drivers/mmc/host/sdhci-xenon.c
> create mode 100644 drivers/mmc/host/sdhci-xenon.h
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 850a0afb0c8d..d92f4175574b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7608,6 +7608,7 @@ MARVELL XENON MMC/SD/SDIO HOST CONTROLLER DRIVER
> M: Ziji Hu <huziji@xxxxxxxxxxx>
> L: linux-mmc@xxxxxxxxxxxxxxx
> S: Supported
> +F: drivers/mmc/host/sdhci-xenon.*
> F: Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt
>
> MATROX FRAMEBUFFER DRIVER
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 5274f503a39a..85a53623526a 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -798,3 +798,12 @@ config MMC_SDHCI_BRCMSTB
> Broadcom STB SoCs.
>
> If unsure, say Y.
> +
> +config MMC_SDHCI_XENON
> + tristate "Marvell Xenon eMMC/SD/SDIO SDHCI driver"
> + depends on MMC_SDHCI && MMC_SDHCI_PLTFM
> + help
> + This selects Marvell Xenon eMMC/SD/SDIO SDHCI.
> + If you have a machine with integrated Marvell Xenon SDHC IP,
> + say Y or M here.
> + If unsure, say N.
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index e2bdaaf43184..75eaf743486c 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -80,3 +80,6 @@ obj-$(CONFIG_MMC_SDHCI_BRCMSTB) += sdhci-brcmstb.o
> ifeq ($(CONFIG_CB710_DEBUG),y)
> CFLAGS-cb710-mmc += -DDEBUG
> endif
> +
> +obj-$(CONFIG_MMC_SDHCI_XENON) += sdhci-xenon-driver.o
> +sdhci-xenon-driver-y += sdhci-xenon.o
> diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
> new file mode 100644
> index 000000000000..3ea059f2aaab
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-xenon.c
> @@ -0,0 +1,594 @@
> +/*
> + * Driver for Marvell SOC Platform Group Xenon SDHC as a platform device
> + *
> + * Copyright (C) 2016 Marvell, All Rights Reserved.
> + *
> + * Author: Hu Ziji <huziji@xxxxxxxxxxx>
> + * Date: 2016-8-24
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * Inspired by Jisheng Zhang <jszhang@xxxxxxxxxxx>
> + * Special thanks to Video BG4 project team.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/mmc/host.h>
> +#include <linux/mmc/mmc.h>
> +#include <linux/mmc/sdio.h>
> +#include <linux/mmc/card.h>
> +#include <linux/mmc/host.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +
> +#include "sdhci-pltfm.h"
> +#include "sdhci.h"
> +#include "sdhci-xenon.h"
> +
> +/* Set SDCLK-off-while-idle */
> +static void xenon_set_sdclk_off_idle(struct sdhci_host *host,
> + unsigned char slot_idx, bool enable)
> +{
> + u32 reg;
> + u32 mask;
> +
> + reg = sdhci_readl(host, SDHC_SYS_OP_CTRL);
> + /* Get the bit shift basing on the slot index */
> + mask = (0x1 << (SDCLK_IDLEOFF_ENABLE_SHIFT + slot_idx));
> + if (enable)
> + reg |= mask;
> + else
> + reg &= ~mask;
> +
> + sdhci_writel(host, reg, SDHC_SYS_OP_CTRL);
> +}
> +
> +/* Enable/Disable the Auto Clock Gating function */
> +static void xenon_set_acg(struct sdhci_host *host, bool enable)
> +{
> + u32 reg;
> +
> + reg = sdhci_readl(host, SDHC_SYS_OP_CTRL);
> + if (enable)
> + reg &= ~AUTO_CLKGATE_DISABLE_MASK;
> + else
> + reg |= AUTO_CLKGATE_DISABLE_MASK;
> + sdhci_writel(host, reg, SDHC_SYS_OP_CTRL);
> +}
> +
> +/* Enable this slot */
> +static void xenon_enable_slot(struct sdhci_host *host,
> + unsigned char slot_idx)
> +{
> + u32 reg;
> +
> + reg = sdhci_readl(host, SDHC_SYS_OP_CTRL);
> + reg |= (BIT(slot_idx) << SLOT_ENABLE_SHIFT);
> + sdhci_writel(host, reg, SDHC_SYS_OP_CTRL);
> +
> + /*
> + * Manually set the flag which all the slots require,
> + * including SD, eMMC, SDIO
> + */
> + host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY;
> +}
> +
> +/* Disable this slot */
> +static void xenon_disable_slot(struct sdhci_host *host,
> + unsigned char slot_idx)
> +{
> + u32 reg;
> +
> + reg = sdhci_readl(host, SDHC_SYS_OP_CTRL);
> + reg &= ~(BIT(slot_idx) << SLOT_ENABLE_SHIFT);
> + sdhci_writel(host, reg, SDHC_SYS_OP_CTRL);
> +}
> +
> +/* Enable Parallel Transfer Mode */
> +static void xenon_enable_slot_parallel_tran(struct sdhci_host *host,
> + unsigned char slot_idx)
> +{
> + u32 reg;
> +
> + reg = sdhci_readl(host, SDHC_SYS_EXT_OP_CTRL);
> + reg |= BIT(slot_idx);
> + sdhci_writel(host, reg, SDHC_SYS_EXT_OP_CTRL);
> +}
> +
> +static void xenon_slot_tuning_setup(struct sdhci_host *host)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + u32 reg;
> +
> + /* Disable the Re-Tuning Request functionality */
> + reg = sdhci_readl(host, SDHC_SLOT_RETUNING_REQ_CTRL);
> + reg &= ~RETUNING_COMPATIBLE;
> + sdhci_writel(host, reg, SDHC_SLOT_RETUNING_REQ_CTRL);
> +
> + /* Disable the Re-tuning Event Signal Enable */
> + reg = sdhci_readl(host, SDHCI_SIGNAL_ENABLE);
> + reg &= ~SDHCI_INT_RETUNE;
> + sdhci_writel(host, reg, SDHCI_SIGNAL_ENABLE);
> +
> + /* Force to use Tuning Mode 1 */
> + host->tuning_mode = SDHCI_TUNING_MODE_1;
> + /* Set re-tuning period */
> + host->tuning_count = 1 << (priv->tuning_count - 1);
> +}
> +
> +/*
> + * Operations inside struct sdhci_ops
> + */
> +/* Recover the Register Setting cleared during SOFTWARE_RESET_ALL */
> +static void sdhci_xenon_reset_exit(struct sdhci_host *host,
> + unsigned char slot_idx, u8 mask)
> +{
> + /* Only SOFTWARE RESET ALL will clear the register setting */
> + if (!(mask & SDHCI_RESET_ALL))
> + return;
> +
> + /* Disable tuning request and auto-retuning again */
> + xenon_slot_tuning_setup(host);
> +
> + xenon_set_acg(host, true);
> +
> + xenon_set_sdclk_off_idle(host, slot_idx, false);
> +}
> +
> +static void sdhci_xenon_reset(struct sdhci_host *host, u8 mask)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> +
> + sdhci_reset(host, mask);
> + sdhci_xenon_reset_exit(host, priv->slot_idx, mask);
> +}
> +
> +/*
> + * Xenon defines different values for HS200 and SDR104
> + * in Host_Control_2
> + */
> +static void xenon_set_uhs_signaling(struct sdhci_host *host,
> + unsigned int timing)
> +{
> + u16 ctrl_2;
> +
> + ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + /* Select Bus Speed Mode for host */
> + ctrl_2 &= ~SDHCI_CTRL_UHS_MASK;
> + if (timing == MMC_TIMING_MMC_HS200)
> + ctrl_2 |= XENON_SDHCI_CTRL_HS200;
> + else if (timing == MMC_TIMING_UHS_SDR104)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR104;
> + else if (timing == MMC_TIMING_UHS_SDR12)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR12;
> + else if (timing == MMC_TIMING_UHS_SDR25)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR25;
> + else if (timing == MMC_TIMING_UHS_SDR50)
> + ctrl_2 |= SDHCI_CTRL_UHS_SDR50;
> + else if ((timing == MMC_TIMING_UHS_DDR50) ||
> + (timing == MMC_TIMING_MMC_DDR52))
> + ctrl_2 |= SDHCI_CTRL_UHS_DDR50;
> + else if (timing == MMC_TIMING_MMC_HS400)
> + ctrl_2 |= XENON_SDHCI_CTRL_HS400;
> + sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
> +}
> +
> +static const struct sdhci_ops sdhci_xenon_ops = {
> + .set_clock = sdhci_set_clock,
> + .set_bus_width = sdhci_set_bus_width,
> + .reset = sdhci_xenon_reset,
> + .set_uhs_signaling = xenon_set_uhs_signaling,
> + .get_max_clock = sdhci_pltfm_clk_get_max_clock,
> +};
> +
> +static const struct sdhci_pltfm_data sdhci_xenon_pdata = {
> + .ops = &sdhci_xenon_ops,
> + .quirks = SDHCI_QUIRK_NO_ENDATTR_IN_NOPDESC |
> + SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER |
> + SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> +};
> +
> +/*
> + * Xenon Specific Operations in mmc_host_ops
> + */
> +static void xenon_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + unsigned long flags;
> + u32 reg;
> +
> + /*
> + * HS400/HS200/eMMC HS doesn't have Preset Value register.
> + * However, sdhci_set_ios will read HS400/HS200 Preset register.
> + * Disable Preset Value register for HS400/HS200.
> + * eMMC HS with preset_enabled set will trigger a bug in
> + * get_preset_value().
> + */
> + spin_lock_irqsave(&host->lock, flags);
> + if ((ios->timing == MMC_TIMING_MMC_HS400) ||
> + (ios->timing == MMC_TIMING_MMC_HS200) ||
> + (ios->timing == MMC_TIMING_MMC_HS)) {
> + host->preset_enabled = false;
> + host->quirks2 |= SDHCI_QUIRK2_PRESET_VALUE_BROKEN;
> +
> + reg = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + reg &= ~SDHCI_CTRL_PRESET_VAL_ENABLE;
> + sdhci_writew(host, reg, SDHCI_HOST_CONTROL2);
> + } else {
> + host->quirks2 &= ~SDHCI_QUIRK2_PRESET_VALUE_BROKEN;
> + }
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + sdhci_set_ios(mmc, ios);
> +
> + if (host->clock > DEFAULT_SDCLK_FREQ) {
> + spin_lock_irqsave(&host->lock, flags);
> + xenon_set_sdclk_off_idle(host, priv->slot_idx, true);
> + spin_unlock_irqrestore(&host->lock, flags);
> + }
> +}
> +
> +static int __emmc_signal_voltage_switch(struct mmc_host *mmc,
> + const unsigned char signal_voltage)
> +{
> + u32 ctrl;
> + unsigned char voltage_code;
> + struct sdhci_host *host = mmc_priv(mmc);
> +
> + if (signal_voltage == MMC_SIGNAL_VOLTAGE_330)
> + voltage_code = EMMC_VCCQ_3_3V;
> + else if (signal_voltage == MMC_SIGNAL_VOLTAGE_180)
> + voltage_code = EMMC_VCCQ_1_8V;
> + else
> + return -EINVAL;
> +
> + /*
> + * This host is for eMMC, XENON self-defined
> + * eMMC slot control register should be accessed
> + * instead of Host Control 2
> + */
> + ctrl = sdhci_readl(host, SDHC_SLOT_EMMC_CTRL);
> + ctrl &= ~EMMC_VCCQ_MASK;
> + ctrl |= voltage_code;
> + sdhci_writel(host, ctrl, SDHC_SLOT_EMMC_CTRL);
> +
> + /* There is no standard to determine this waiting period */
> + usleep_range(1000, 2000);
> +
> + /* Check whether io voltage switch is done */
> + ctrl = sdhci_readl(host, SDHC_SLOT_EMMC_CTRL);
> + ctrl &= EMMC_VCCQ_MASK;
> + /*
> + * This bit is set only when regulator feeds back the voltage switch
> + * results to Xenon SDHC.
> + * However, in actaul implementation, regulator might not provide
> + * this feedback.
> + * Thus we shall not rely on this bit to determine if switch failed.
> + * If the bit is not set, just throw a message.
> + * Besides, error code should not be returned.
> + */
> + if (ctrl != voltage_code)
> + dev_info(mmc_dev(mmc), "fail to detect eMMC signal voltage stable\n");
> + return 0;
> +}
> +
> +static int xenon_emmc_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + unsigned char voltage = ios->signal_voltage;
> +
> + if ((voltage == MMC_SIGNAL_VOLTAGE_330) ||
> + (voltage == MMC_SIGNAL_VOLTAGE_180))
> + return __emmc_signal_voltage_switch(mmc, voltage);
> +
> + dev_err(mmc_dev(mmc), "Unsupported signal voltage: %d\n",
> + voltage);
> + return -EINVAL;

This wrapper function seems unnessarry. It only adds a dev_err(), so
then might as well do that in __emmc_signal_voltage_switch().

> +}
> +
> +static int xenon_start_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> +
> + /*
> + * Before SD/SDIO set signal voltage, SD bus clock should be
> + * disabled. However, sdhci_set_clock will also disable the Internal
> + * clock in mmc_set_signal_voltage().

If that's the case then that is wrong in the generic sdhci code.
What's the reason why it can't be fixed there instead of having this
workaround?

> + * If Internal clock is disabled, the 3.3V/1.8V bit can not be updated.
> + * Thus here manually enable internal clock.
> + *
> + * After switch completes, it is unnecessary to disable internal clock,
> + * since keeping internal clock active obeys SD spec.
> + */
> + enable_xenon_internal_clk(host);
> +
> + if (priv->emmc_slot)
> + return xenon_emmc_signal_voltage_switch(mmc, ios);
> +
> + return sdhci_start_signal_voltage_switch(mmc, ios);
> +}
> +
> +/*
> + * After determining which slot is used for SDIO,
> + * some additional task is required.
> + */
> +static void xenon_init_card(struct mmc_host *mmc, struct mmc_card *card)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + u32 reg;
> + u8 slot_idx;
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> +
> + /* Link the card for delay adjustment */
> + priv->card_candidate = card;
> + /* Set tuning functionality of this slot */
> + xenon_slot_tuning_setup(host);

This looks weird. I assume this can be done as a part of the regular
tuning seqeunce!?

> +
> + slot_idx = priv->slot_idx;
> + if (!mmc_card_sdio(card)) {
> + /* Clear SDIO Card Inserted indication */

Why do you need this?

If you need to reset this, I think it's better to do it from
->set_ios() at MMC_POWER_OFF.

> + reg = sdhci_readl(host, SDHC_SYS_CFG_INFO);
> + reg &= ~(1 << (slot_idx + SLOT_TYPE_SDIO_SHIFT));
> + sdhci_writel(host, reg, SDHC_SYS_CFG_INFO);
> +
> + if (mmc_card_mmc(card)) {
> + mmc->caps |= MMC_CAP_NONREMOVABLE;
> + if (!(host->quirks2 & SDHCI_QUIRK2_NO_1_8_V))
> + mmc->caps |= MMC_CAP_1_8V_DDR;
> + /*
> + * Force to clear BUS_TEST to
> + * skip bus_test_pre and bus_test_post
> + */
> + mmc->caps &= ~MMC_CAP_BUS_WIDTH_TEST;
> + mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ |
> + MMC_CAP2_PACKED_CMD;
> + if (mmc->caps & MMC_CAP_8_BIT_DATA)
> + mmc->caps2 |= MMC_CAP2_HS400_1_8V;

Most of this can be specified as DT configurations. Please use that instead.

More importantly, please don't use the ->init_card() ops to assign
host caps. If not DT, please do it from ->probe().

> + }
> + } else {
> + /*
> + * Set SDIO Card Inserted indication
> + * to inform that the current slot is for SDIO
> + */
> + reg = sdhci_readl(host, SDHC_SYS_CFG_INFO);
> + reg |= (1 << (slot_idx + SLOT_TYPE_SDIO_SHIFT));
> + sdhci_writel(host, reg, SDHC_SYS_CFG_INFO);

So this makes sence to have in the ->init_card() ops. The rest above, not.

> + }
> +}
> +
> +static int xenon_execute_tuning(struct mmc_host *mmc, u32 opcode)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> +
> + if (host->timing == MMC_TIMING_UHS_DDR50)
> + return 0;
> +
> + return sdhci_execute_tuning(mmc, opcode);
> +}
> +
> +static void xenon_replace_mmc_host_ops(struct sdhci_host *host)
> +{
> + host->mmc_host_ops.set_ios = xenon_set_ios;
> + host->mmc_host_ops.start_signal_voltage_switch =
> + xenon_start_signal_voltage_switch;
> + host->mmc_host_ops.init_card = xenon_init_card;
> + host->mmc_host_ops.execute_tuning = xenon_execute_tuning;
> +}
> +
> +static int xenon_probe_dt(struct platform_device *pdev)
> +{
> + struct device_node *np = pdev->dev.of_node;
> + struct sdhci_host *host = platform_get_drvdata(pdev);
> + struct mmc_host *mmc = host->mmc;
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + int err;
> + u32 slot_idx, nr_slot;
> + u32 tuning_count;
> + u32 reg;
> +
> + /* Standard MMC property */
> + err = mmc_of_parse(mmc);
> + if (err)
> + return err;
> +
> + /* Standard SDHCI property */
> + sdhci_get_of_property(pdev);
> +
> + /*
> + * Xenon Specific property:
> + * emmc: explicitly indicate whether this slot is for eMMC
> + * slotno: the index of slot. Refer to SDHC_SYS_CFG_INFO register
> + * tun-count: the interval between re-tuning
> + * PHY type: "sdhc phy", "emmc phy 5.0" or "emmc phy 5.1"
> + */
> + if (of_property_read_bool(np, "marvell,xenon-emmc"))
> + priv->emmc_slot = true;

So, you need this because of the eMMC voltage switch behaviour, right?

Then I would rather like to describe this a generic DT bindings for
the eMMC voltage level support. There have acutally been some earlier
discussions for this, but we haven't yet made some changes.

I think what is missing is a mmc-ddr-3_3v DT binding, which when set,
allows the host driver to accept I/O voltage switches to 3.3V. If not
supported the ->start_signal_voltage_switch() ops may return -EINVAL.
This would inform the mmc core to move on to the next supported
voltage level. There might be some minor additional changes to the mmc
card initialization sequence, but those should be simple.

I can help out to look into this, unless you want to do it yourself of course!?

> + else
> + priv->emmc_slot = false;
> +
> + if (!of_property_read_u32(np, "marvell,xenon-slotno", &slot_idx)) {
> + nr_slot = sdhci_readl(host, SDHC_SYS_CFG_INFO);
> + nr_slot &= NR_SUPPORTED_SLOT_MASK;
> + if (unlikely(slot_idx > nr_slot)) {
> + dev_err(mmc_dev(mmc), "Slot Index %d exceeds Number of slots %d\n",
> + slot_idx, nr_slot);
> + return -EINVAL;
> + }
> + } else {
> + priv->slot_idx = 0x0;
> + }
> +
> + if (!of_property_read_u32(np, "marvell,xenon-tun-count",
> + &tuning_count)) {
> + if (unlikely(tuning_count >= TMR_RETUN_NO_PRESENT)) {
> + dev_err(mmc_dev(mmc), "Wrong Re-tuning Count. Set default value %d\n",
> + DEF_TUNING_COUNT);
> + tuning_count = DEF_TUNING_COUNT;
> + }
> + } else {
> + priv->tuning_count = DEF_TUNING_COUNT;
> + }

To make the code a bit easier...

Maybe set "priv->tuning_count = DEF_TUNING_COUNT" before the "if", and
instead have the of_property_read_u32() to update the value when set.

> +
> + if (of_property_read_bool(np, "marvell,xenon-mask-conflict-err")) {
> + reg = sdhci_readl(host, SDHC_SYS_EXT_OP_CTRL);
> + reg |= MASK_CMD_CONFLICT_ERROR;
> + sdhci_writel(host, reg, SDHC_SYS_EXT_OP_CTRL);
> + }
> +
> + return err;
> +}
> +
> +static int xenon_slot_probe(struct sdhci_host *host)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + u8 slot_idx = priv->slot_idx;
> +
> + /* Enable slot */
> + xenon_enable_slot(host, slot_idx);
> +
> + /* Enable ACG */
> + xenon_set_acg(host, true);
> +
> + /* Enable Parallel Transfer Mode */
> + xenon_enable_slot_parallel_tran(host, slot_idx);
> +
> + priv->timing = MMC_TIMING_FAKE;
> + priv->clock = 0;

What are these used for?

> +
> + return 0;
> +}
> +
> +static void xenon_slot_remove(struct sdhci_host *host)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + u8 slot_idx = priv->slot_idx;
> +
> + /* disable slot */
> + xenon_disable_slot(host, slot_idx);
> +}
> +
> +static int sdhci_xenon_probe(struct platform_device *pdev)
> +{
> + struct sdhci_pltfm_host *pltfm_host;
> + struct sdhci_host *host;
> + struct clk *clk, *axi_clk;
> + struct sdhci_xenon_priv *priv;
> + int err;
> +
> + host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,
> + sizeof(struct sdhci_xenon_priv));
> + if (IS_ERR(host))
> + return PTR_ERR(host);
> +
> + pltfm_host = sdhci_priv(host);
> + priv = sdhci_pltfm_priv(pltfm_host);
> +
> + xenon_set_acg(host, false);
> +
> + /*
> + * Link Xenon specific mmc_host_ops function,
> + * to replace standard ones in sdhci_ops.
> + */
> + xenon_replace_mmc_host_ops(host);
> +
> + clk = devm_clk_get(&pdev->dev, "core");
> + if (IS_ERR(clk)) {
> + dev_err(&pdev->dev, "Failed to setup input clk.\n");
> + err = PTR_ERR(clk);
> + goto free_pltfm;
> + }
> + clk_prepare_enable(clk);

Check error code.

> + pltfm_host->clk = clk;

Why not assign pltfm_host->clk immedately when doing devm_clk_get(),
that would make this a bit cleaner, right?

> +
> + /*
> + * Some SOCs require additional clock to
> + * manage AXI bus clock.
> + * It is optional.
> + */
> + axi_clk = devm_clk_get(&pdev->dev, "axi");
> + if (!IS_ERR(axi_clk)) {
> + clk_prepare_enable(axi_clk);
> + priv->axi_clk = axi_clk;
> + }

Same comments as for the above core clock.

> +
> + err = xenon_probe_dt(pdev);
> + if (err)
> + goto err_clk;
> +
> + err = xenon_slot_probe(host);
> + if (err)
> + goto err_clk;
> +
> + err = sdhci_add_host(host);
> + if (err)
> + goto remove_slot;
> +
> + return 0;
> +
> +remove_slot:
> + xenon_slot_remove(host);
> +err_clk:
> + clk_disable_unprepare(pltfm_host->clk);
> + if (!IS_ERR(axi_clk))
> + clk_disable_unprepare(axi_clk);
> +free_pltfm:
> + sdhci_pltfm_free(pdev);
> + return err;
> +}
> +
> +static int sdhci_xenon_remove(struct platform_device *pdev)
> +{
> + struct sdhci_host *host = platform_get_drvdata(pdev);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + int dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xFFFFFFFF);
> +
> + xenon_slot_remove(host);
> +
> + sdhci_remove_host(host, dead);
> +
> + clk_disable_unprepare(pltfm_host->clk);
> + clk_disable_unprepare(priv->axi_clk);
> +
> + sdhci_pltfm_free(pdev);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id sdhci_xenon_dt_ids[] = {
> + { .compatible = "marvell,xenon-sdhci",},
> + { .compatible = "marvell,armada-3700-sdhci",},
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, sdhci_xenon_dt_ids);
> +
> +static struct platform_driver sdhci_xenon_driver = {
> + .driver = {
> + .name = "xenon-sdhci",
> + .of_match_table = sdhci_xenon_dt_ids,
> + .pm = &sdhci_pltfm_pmops,
> + },
> + .probe = sdhci_xenon_probe,
> + .remove = sdhci_xenon_remove,
> +};
> +
> +module_platform_driver(sdhci_xenon_driver);
> +
> +MODULE_DESCRIPTION("SDHCI platform driver for Marvell Xenon SDHC");
> +MODULE_AUTHOR("Hu Ziji <huziji@xxxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/mmc/host/sdhci-xenon.h b/drivers/mmc/host/sdhci-xenon.h
> new file mode 100644
> index 000000000000..4601d0a4b22f
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-xenon.h

I don't think you need a specific header for this, let's instead just
put everthing in the c-file.

> @@ -0,0 +1,142 @@
> +/*
> + * Copyright (C) 2016 Marvell, All Rights Reserved.
> + *
> + * Author: Hu Ziji <huziji@xxxxxxxxxxx>
> + * Date: 2016-8-24
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + */
> +#ifndef SDHCI_XENON_H_
> +#define SDHCI_XENON_H_
> +
> +#include <linux/clk.h>
> +#include <linux/mmc/card.h>
> +#include <linux/of.h>
> +#include "sdhci.h"
> +
> +/* Register Offset of SD Host Controller SOCP self-defined register */
> +#define SDHC_SYS_CFG_INFO 0x0104
> +#define SLOT_TYPE_SDIO_SHIFT 24
> +#define SLOT_TYPE_EMMC_MASK 0xFF
> +#define SLOT_TYPE_EMMC_SHIFT 16
> +#define SLOT_TYPE_SD_SDIO_MMC_MASK 0xFF
> +#define SLOT_TYPE_SD_SDIO_MMC_SHIFT 8
> +#define NR_SUPPORTED_SLOT_MASK 0x7
> +
> +#define SDHC_SYS_OP_CTRL 0x0108
> +#define AUTO_CLKGATE_DISABLE_MASK BIT(20)
> +#define SDCLK_IDLEOFF_ENABLE_SHIFT 8
> +#define SLOT_ENABLE_SHIFT 0
> +
> +#define SDHC_SYS_EXT_OP_CTRL 0x010C
> +#define MASK_CMD_CONFLICT_ERROR BIT(8)
> +
> +#define SDHC_SLOT_OP_STATUS_CTRL 0x0128
> +#define DELAY_90_DEGREE_MASK_EMMC5 BIT(7)
> +#define DELAY_90_DEGREE_SHIFT_EMMC5 7
> +#define EMMC_5_0_PHY_FIXED_DELAY_MASK 0x7F
> +#define EMMC_PHY_FIXED_DELAY_MASK 0xFF
> +#define EMMC_PHY_FIXED_DELAY_WINDOW_MIN (EMMC_PHY_FIXED_DELAY_MASK >> 3)
> +#define SDH_PHY_FIXED_DELAY_MASK 0x1FF
> +#define SDH_PHY_FIXED_DELAY_WINDOW_MIN (SDH_PHY_FIXED_DELAY_MASK >> 4)
> +
> +#define TUN_CONSECUTIVE_TIMES_SHIFT 16
> +#define TUN_CONSECUTIVE_TIMES_MASK 0x7
> +#define TUN_CONSECUTIVE_TIMES 0x4
> +#define TUNING_STEP_SHIFT 12
> +#define TUNING_STEP_MASK 0xF
> +#define TUNING_STEP_DIVIDER BIT(6)
> +
> +#define FORCE_SEL_INVERSE_CLK_SHIFT 11
> +
> +#define SDHC_SLOT_EMMC_CTRL 0x0130
> +#define ENABLE_DATA_STROBE BIT(24)
> +#define SET_EMMC_RSTN BIT(16)
> +#define DISABLE_RD_DATA_CRC BIT(14)
> +#define DISABLE_CRC_STAT_TOKEN BIT(13)
> +#define EMMC_VCCQ_MASK 0x3
> +#define EMMC_VCCQ_1_8V 0x1
> +#define EMMC_VCCQ_3_3V 0x3
> +
> +#define SDHC_SLOT_RETUNING_REQ_CTRL 0x0144
> +/* retuning compatible */
> +#define RETUNING_COMPATIBLE 0x1
> +
> +#define SDHC_SLOT_EXT_PRESENT_STATE 0x014C
> +#define LOCK_STATE 0x1
> +
> +#define SDHC_SLOT_DLL_CUR_DLY_VAL 0x0150
> +
> +/* Tuning Parameter */
> +#define TMR_RETUN_NO_PRESENT 0xF
> +#define DEF_TUNING_COUNT 0x9
> +
> +#define MMC_TIMING_FAKE 0xFF
> +
> +#define DEFAULT_SDCLK_FREQ (400000)
> +
> +/* Xenon specific Mode Select value */
> +#define XENON_SDHCI_CTRL_HS200 0x5
> +#define XENON_SDHCI_CTRL_HS400 0x6

For all defines above:

All these defines needs some *SDHCI* prefix. Can you please update that.

> +
> +struct sdhci_xenon_priv {
> + /*
> + * The bus_width, timing, and clock fields in below
> + * record the current setting of Xenon SDHC.
> + * Driver will call a Sampling Fixed Delay Adjustment
> + * if any setting is changed.
> + */
> + unsigned char bus_width;
> + unsigned char timing;

These two are not used. Please remove.

> + unsigned char tuning_count;
> + unsigned int clock;

"clock" isn't used, please remove.

> + struct clk *axi_clk;
> +
> + /* Slot idx */
> + u8 slot_idx;
> + /* Whether this slot is for eMMC */
> + bool emmc_slot;
> +
> + /*
> + * When initializing card, Xenon has to determine card type and
> + * adjust Sampling Fixed delay for the speed mode in which
> + * DLL tuning is not support.
> + * However, at that time, card structure is not linked to mmc_host.
> + * Thus a card pointer is added here to provide
> + * the delay adjustment function with the card structure
> + * of the card during initialization.
> + *
> + * It is only valid during initialization after it is updated in
> + * xenon_init_card().
> + * Do not access this variable in normal transfers after
> + * initialization completes.
> + */
> + struct mmc_card *card_candidate;

Not activley used in this change, please remove and let's discuss it
in the next step.

> +};
> +
> +static inline int enable_xenon_internal_clk(struct sdhci_host *host)
> +{
> + u32 reg;
> + u8 timeout;
> +
> + reg = sdhci_readl(host, SDHCI_CLOCK_CONTROL);
> + reg |= SDHCI_CLOCK_INT_EN;
> + sdhci_writel(host, reg, SDHCI_CLOCK_CONTROL);
> + /* Wait max 20 ms */
> + timeout = 20;
> + while (!((reg = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
> + & SDHCI_CLOCK_INT_STABLE)) {
> + if (timeout == 0) {
> + pr_err("%s: Internal clock never stabilised.\n",
> + mmc_hostname(host->mmc));
> + return -ETIMEDOUT;
> + }
> + timeout--;
> + mdelay(1);
> + }
> +
> + return 0;
> +}
> +#endif
> --
> git-series 0.8.10

Kind regards
Uffe