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    Subject[PATCH 5.4 17/57] mmc: meson-mx-sdio: remove the broken ->card_busy() op
    Date
    From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

    commit ddca1092c4324c89cf692b5efe655aa251864b51 upstream.

    The recent commit 0d84c3e6a5b2 ("mmc: core: Convert to
    mmc_poll_for_busy() for erase/trim/discard") makes use of the
    ->card_busy() op for SD cards. This uncovered that the ->card_busy() op
    in the Meson SDIO driver was never working right:
    while polling the busy status with ->card_busy()
    meson_mx_mmc_card_busy() reads only one of the two MESON_MX_SDIO_IRQC
    register values 0x1f001f10 or 0x1f003f10. This translates to "three out
    of four DAT lines are HIGH" and "all four DAT lines are HIGH", which
    is interpreted as "the card is busy".

    It turns out that no situation can be observed where all four DAT lines
    are LOW, meaning the card is not busy anymore. Upon further research the
    3.10 vendor driver for this controller does not implement the
    ->card_busy() op.

    Remove the ->card_busy() op from the meson-mx-sdio driver since it is
    not working. At the time of writing this patch it is not clear what's
    needed to make the ->card_busy() implementation work with this specific
    controller hardware. For all use-cases which have previously worked the
    MMC_CAP_WAIT_WHILE_BUSY flag is now taking over, even if we don't have
    a ->card_busy() op anymore.

    Fixes: ed80a13bb4c4c9 ("mmc: meson-mx-sdio: Add a driver for the Amlogic Meson8 and Meson8b SoCs")
    Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/r/20200416183513.993763-3-martin.blumenstingl@googlemail.com
    Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/mmc/host/meson-mx-sdio.c | 9 ---------
    1 file changed, 9 deletions(-)

    --- a/drivers/mmc/host/meson-mx-sdio.c
    +++ b/drivers/mmc/host/meson-mx-sdio.c
    @@ -357,14 +357,6 @@ static void meson_mx_mmc_request(struct
    meson_mx_mmc_start_cmd(mmc, mrq->cmd);
    }

    -static int meson_mx_mmc_card_busy(struct mmc_host *mmc)
    -{
    - struct meson_mx_mmc_host *host = mmc_priv(mmc);
    - u32 irqc = readl(host->base + MESON_MX_SDIO_IRQC);
    -
    - return !!(irqc & MESON_MX_SDIO_IRQC_FORCE_DATA_DAT_MASK);
    -}
    -
    static void meson_mx_mmc_read_response(struct mmc_host *mmc,
    struct mmc_command *cmd)
    {
    @@ -506,7 +498,6 @@ static void meson_mx_mmc_timeout(struct
    static struct mmc_host_ops meson_mx_mmc_ops = {
    .request = meson_mx_mmc_request,
    .set_ios = meson_mx_mmc_set_ios,
    - .card_busy = meson_mx_mmc_card_busy,
    .get_cd = mmc_gpio_get_cd,
    .get_ro = mmc_gpio_get_ro,
    };

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