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

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

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
>