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    SubjectRe: [PATCH v2 1/2] mmc: dw_mmc: fix bug that cause 'Timeout sending command'
    Hi Alim,

    On 02/11/2015 03:57 AM, Addy wrote:
    >
    > On 2015/02/10 23:22, Alim Akhtar wrote:
    >> Hi Addy,
    >>
    >> On Mon, Feb 9, 2015 at 12:55 PM, Addy Ke <addy.ke@rock-chips.com> wrote:
    >>> Because of some uncertain factors, such as worse card or worse hardware,
    >>> DAT[3:0](the data lines) may be pulled down by card, and mmc controller
    >>> will be in busy state. This should not happend when mmc controller
    >>> send command to update card clocks. If this happends, mci_send_cmd will
    >>> be failed and we will get 'Timeout sending command', and then system will
    >>> be blocked. To avoid this, we need reset mmc controller.
    >>>
    >>> Signed-off-by: Addy Ke <addy.ke@rock-chips.com>
    >>> ---
    >>> drivers/mmc/host/dw_mmc.c | 28 ++++++++++++++++++++++++++++
    >>> 1 file changed, 28 insertions(+)
    >>>
    >>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
    >>> index 4d2e3c2..b0b57e3 100644
    >>> --- a/drivers/mmc/host/dw_mmc.c
    >>> +++ b/drivers/mmc/host/dw_mmc.c
    >>> @@ -100,6 +100,7 @@ struct idmac_desc {
    >>> };
    >>> #endif /* CONFIG_MMC_DW_IDMAC */
    >>>
    >>> +static int dw_mci_card_busy(struct mmc_host *mmc);
    >>> static bool dw_mci_reset(struct dw_mci *host);
    >>> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
    >>>
    >>> @@ -888,6 +889,31 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
    >>> cmd, arg, cmd_status);
    >>> }
    >>>
    >>> +static void dw_mci_wait_busy(struct dw_mci_slot *slot)
    >>> +{
    >>> + struct dw_mci *host = slot->host;
    >>> + unsigned long timeout = jiffies + msecs_to_jiffies(500);
    >>> +
    >> Why 500 msec?
    > This timeout value is the same as mci_send_cmd:
    > static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
    > {
    > struct dw_mci *host = slot->host;
    > unsigned long timeout = jiffies + msecs_to_jiffies(500);
    > ....
    > }
    >
    > I have not clear that which is suitable.
    > Do you have any suggestion on it?
    >>
    >>> + do {
    >>> + if (!dw_mci_card_busy(slot->mmc))
    >>> + return;
    >>> + cpu_relax();
    >>> + } while (time_before(jiffies, timeout));
    >>> +
    >>> + dev_err(host->dev, "Data busy (status %#x)\n",
    >>> + mci_readl(slot->host, STATUS));
    >>> +
    >>> + /*
    >>> + * Data busy, this should not happend when mmc controller send command
    >>> + * to update card clocks in non-volt-switch state. If it happends, we
    >>> + * should reset controller to avoid getting "Timeout sending command".
    >>> + */
    >>> + dw_mci_ctrl_reset(host, SDMMC_CTRL_ALL_RESET_FLAGS);
    >>> +
    >> Why you need to reset all blocks? may be CTRL_RESET is good enough here.
    > I have tested on rk3288, if only reset ctroller, data busy bit will not
    > be cleaned,and we will still get
    >
    > "Timeout sending command".
    >
    >>
    >>> + /* Fail to reset controller or still data busy, WARN_ON! */
    >>> + WARN_ON(dw_mci_card_busy(slot->mmc));
    >>> +}
    >>> +
    >>> static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
    >>> {
    >>> struct dw_mci *host = slot->host;
    >>> @@ -899,6 +925,8 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot, bool force_clkinit)
    >>> /* We must continue to set bit 28 in CMD until the change is complete */
    >>> if (host->state == STATE_WAITING_CMD11_DONE)
    >>> sdmmc_cmd_bits |= SDMMC_CMD_VOLT_SWITCH;
    >>> + else
    >>> + dw_mci_wait_busy(slot);
    >>>
    >> hmm...I would suggest you to call dw_mci_wait_busy() from inside
    >> mci_send_cmd(), seems like dw_mmc hangs while sending update clock cmd
    >> in multiple cases.see [1]
    >>
    >> [1]: http://permalink.gmane.org/gmane.linux.kernel.mmc/31140
    > I think this patch is more reasonable.
    > So I will resend patches based on this patch.
    > thank you!

    I have tested your patches instead [1] above and they do not solve my issue:
    Board: odroid-xu3/exynos5422/dw_mmc_250a.
    MMC card: absent, broken-cd quirk
    SD card: present

    System hangs during boot after few minutes kernel spits:
    [ 242.188098] INFO: task kworker/u16:1:50 blocked for more than 120
    seconds.
    [ 242.193524] Not tainted
    3.19.0-next-20150210-00002-gf96831b-dirty #3834
    [ 242.200622] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs"
    disables this message.
    [ 242.208422] kworker/u16:1 D c04766ac 0 50 2 0x00000000
    [ 242.214756] Workqueue: kmmcd mmc_rescan
    [ 242.218553] [<c04766ac>] (__schedule) from [<c0476a58>]
    (schedule+0x34/0x98)
    [ 242.225591] [<c0476a58>] (schedule) from [<c047a4dc>]
    (schedule_timeout+0x110/0x164)
    [ 242.233302] [<c047a4dc>] (schedule_timeout) from [<c04774f0>]
    (wait_for_common+0xb8/0x14c)
    [ 242.241539] [<c04774f0>] (wait_for_common) from [<c0362138>]
    (mmc_wait_for_req+0x68/0x17c)
    [ 242.249861] [<c0362138>] (mmc_wait_for_req) from [<c03622cc>]
    (mmc_wait_for_cmd+0x80/0xa0)
    [ 242.258002] [<c03622cc>] (mmc_wait_for_cmd) from [<c0367e50>]
    (mmc_go_idle+0x78/0xf8)
    [ 242.265796] [<c0367e50>] (mmc_go_idle) from [<c0363e2c>]
    (mmc_rescan+0x280/0x314)
    [ 242.273253] [<c0363e2c>] (mmc_rescan) from [<c0034764>]
    (process_one_work+0x120/0x324)
    [ 242.281135] [<c0034764>] (process_one_work) from [<c00349cc>]
    (worker_thread+0x30/0x42c)
    [ 242.289194] [<c00349cc>] (worker_thread) from [<c003926c>]
    (kthread+0xd8/0xf4)
    [ 242.296389] [<c003926c>] (kthread) from [<c000e7c0>]
    (ret_from_fork+0x14/0x34)

    Just for record, Exynos4412/dw_mmc_240a with the same configuration
    (no MMC card, broken-cd) works OK without patches.


    Regards
    Andrzej

    >>
    >>> if (!clock) {
    >>> mci_writel(host, CLKENA, 0);
    >>> --
    >>> 1.8.3.2
    >>>
    >>>
    >>>
    >>> _______________________________________________
    >>> linux-arm-kernel mailing list
    >>> linux-arm-kernel@lists.infradead.org
    >>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
    >>
    >>
    >
    >
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