Hi,
I looked at the clock thing, and it appears that there's an extra divide
by two in hardware (the TRM says "Clock division is 2*n"), so those
numbers do appear to be correct.
>From some experimentation the other day, it appeared to be a race
condition which is affected by the position of the dev_info (I have a
JTAG console enabled which adds multi-millisecond delays every time
something is printed). So I think the race was always there, but is only
now showing up.
More information:
* it usually alternates between working and not working (works on first
boot), I'm just hard resetting rather than shutting down cleanly.
* unplugging the SD card between boots prevents it going wrong (I don't
believe our board has power control over SD card).
* using old kernel first and then new kernel, failure can still happen,
so the card could always get into the funny state, but it's only now
causing problems.
* forcing a GPIO bitbanging reset on probe to unlock the card stops it
failing (usually this sequence is only initiated if the card is locked
up - i.e. busy. It's our own quirk to the driver).
I'll have another look at it sometime and report back if I find the root
cause.
Thanks
James
On 21/11/12 03:21, Jaehoon Chung wrote:
> Hi All,
>
> Well, i didn't find the James's error message.
> But i confused about the clock value.
>
> Bus speed : 99840000Hz
> request : 200000Hz
> Div : 250
>
> If bus_speed is divided with div, then actual value should be 399360Hz.
> But this log is produced 199680Hz. What's wrong?
>
> I think this message can be confused to debug.
>
> Best Regards,
> Jaehoon Chung
>
> On 11/20/2012 06:39 PM, James Hogan wrote:
>> Hi Yuvaraj,
>>
>> On 20/11/12 05:35, Yuvaraj Kumar wrote:
>>> Its not sufficient.In my case, sdio_reset command was submitted to
>>> dw_mmc controller before interrupts are enabled.
>>> By looking at your log,it seems something wrong with frequency set by
>>> your U-boot.
>>
>> I'm not using U-boot, I'm booting with JTAG. In any case it works if I
>> revert your patch so I think the clocks are fine. I'll continue
>> debugging it and see if I can figure out what's happening.
>>
>> Cheers
>> James
>>
>>>
>>> Best Regards
>>> Yuvaraj
>>>
>>> On Mon, Nov 19, 2012 at 6:50 PM, James Hogan <james.hogan@xxxxxxxxxx> wrote:
>>>> On 19/11/12 13:01, Yuvaraj CD wrote:
>>>>> As mmc_start_host is getting called before enabling the dw_mmc controller
>>>>> interrupt, there is a problem of missing the SDMMC_INT_CMD_DONE for the
>>>>> very first command sent by the sdio_reset.
>>>>> This problem occurs only when we disable MMC debugging i.e, MMC_DEBUG [=n].
>>>>> Hence this patch enables the dw_mmc controller interrupt before mmc_start_host.
>>>>>
>>>>> Signed-off-by: Yuvaraj CD <yuvaraj.cd@xxxxxxxxxxx>
>>>>
>>>> Hi Yuvaraj,
>>>>
>>>> I get the following errors after this patch is applied
>>>> (2da1d7f2948900cd50d38643db39f790edb3cc96, merged in v3.7-rc5) and the
>>>> driver doesn't work as a result. Reverting it fixes the problem.
>>>>
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 300000Hz, actual 298922HZ div = 167)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 200000Hz, actual 199680HZ div = 250)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 195765Hz, actual 195764HZ div = 255)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 400000Hz, actual 399360HZ div = 125)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 300000Hz, actual 298922HZ div = 167)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 200000Hz, actual 199680HZ div = 250)
>>>> mmc0: error -110 whilst initialising SD card
>>>> mmc_host mmc0: Bus speed (slot 0) = 99840000Hz (slot req 195765Hz, actual 195764HZ div = 255)
>>>> mmc0: error -110 whilst initialising SD card
>>>>
>>>> The interrupts are already cleared and disabled at the beginning of the
>>>> probe function, so is the following sufficient (after reverting your
>>>> patch) to fix the problem you've been observing?
>>>>
>>>> Thanks
>>>> James
>>>>
>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>> index ec9b5a8..2be9899 100644
>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>> @@ -2266,7 +2266,6 @@ int dw_mci_probe(struct dw_mci *host)
>>>> * Enable interrupts for command done, data over, data empty, card det,
>>>> * receive ready and error such as transmit, receive timeout, crc error
>>>> */
>>>> - mci_writel(host, RINTSTS, 0xFFFFFFFF);
>>>> mci_writel(host, INTMASK, SDMMC_INT_CMD_DONE | SDMMC_INT_DATA_OVER |
>>>> SDMMC_INT_TXDR | SDMMC_INT_RXDR |
>>>> DW_MCI_ERROR_FLAGS | SDMMC_INT_CD);
>>>>
>>>>
>>>>> ---
>>>>> drivers/mmc/host/dw_mmc.c | 29 +++++++++++++++--------------
>>>>> 1 file changed, 15 insertions(+), 14 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>>>> index a23af77..729c031 100644
>>>>> --- a/drivers/mmc/host/dw_mmc.c
>>>>> +++ b/drivers/mmc/host/dw_mmc.c
>>>>> @@ -2233,6 +2233,21 @@ int dw_mci_probe(struct dw_mci *host)
>>>>> else
>>>>> host->num_slots = ((mci_readl(host, HCON) >> 1) & 0x1F) + 1;
>>>>>
>>>>> + /*
>>>>> + * Enable interrupts for command done, data over, data empty, card det,
>>>>> + * receive ready and error such as transmit, receive timeout, crc error
>>>>> + */
>>>>> + mci_writel(host, RINTSTS, 0xFFFFFFFF);
>>>>> + mci_writel(host, INTMASK, SDMMC_INT_CMD_DONE | SDMMC_INT_DATA_OVER |
>>>>> + SDMMC_INT_TXDR | SDMMC_INT_RXDR |
>>>>> + DW_MCI_ERROR_FLAGS | SDMMC_INT_CD);
>>>>> + mci_writel(host, CTRL, SDMMC_CTRL_INT_ENABLE); /* Enable mci
>>>>> interrupt */
>>>>> +
>>>>> + dev_info(host->dev, "DW MMC controller at irq %d, "
>>>>> + "%d bit host data width, "
>>>>> + "%u deep fifo\n",
>>>>> + host->irq, width, fifo_size);
>>>>> +
>>>>> /* We need at least one slot to succeed */
>>>>> for (i = 0; i < host->num_slots; i++) {
>>>>> ret = dw_mci_init_slot(host, i);
>>>>> @@ -2262,20 +2277,6 @@ int dw_mci_probe(struct dw_mci *host)
>>>>> else
>>>>> host->data_offset = DATA_240A_OFFSET;
>>>>>
>>>>> - /*
>>>>> - * Enable interrupts for command done, data over, data empty, card det,
>>>>> - * receive ready and error such as transmit, receive timeout, crc error
>>>>> - */
>>>>> - mci_writel(host, RINTSTS, 0xFFFFFFFF);
>>>>> - mci_writel(host, INTMASK, SDMMC_INT_CMD_DONE | SDMMC_INT_DATA_OVER |
>>>>> - SDMMC_INT_TXDR | SDMMC_INT_RXDR |
>>>>> - DW_MCI_ERROR_FLAGS | SDMMC_INT_CD);
>>>>> - mci_writel(host, CTRL, SDMMC_CTRL_INT_ENABLE); /* Enable mci
>>>>> interrupt */
>>>>> -
>>>>> - dev_info(host->dev, "DW MMC controller at irq %d, "
>>>>> - "%d bit host data width, "
>>>>> - "%u deep fifo\n",
>>>>> - host->irq, width, fifo_size);
>>>>> if (host->quirks & DW_MCI_QUIRK_IDMAC_DTO)
>>>>> dev_info(host->dev, "Internal DMAC interrupt fix enabled.\n");
>>>>>
>>>>> --
>>>>> 1.7.9.5
>>>>>
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>>>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>>>
>>>>>
>>>>> --
>>>>> James Hogan
>>>>>
>>>>
>>
>>
>
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