Re: [PATCH] mmc: dw_mmc: enable controller interrupt before calling mmc_start_host

[James Hogan <james.hogan@imgtec.com>]

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@imgtec.com> 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@samsung.com>
>>
>> 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
>>>
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>>>
>>> --
>>> James Hogan
>>>
>>