On 26 August 2013 09:20, Seungwon Jeon <[email protected]> wrote:
> While speed mode is changed, CMD13 cannot be guaranteed.
> According to the spec., it is not recommended to use CMD13
> to check the busy completion of the timing change.
> If CMD13 is used in this case, CRC error must be ignored.
>
> Signed-off-by: Seungwon Jeon <[email protected]>
> ---
> Change in v2:
> - Removed function declaration.(From Ulf Hansson)
>
> drivers/mmc/core/mmc_ops.c | 70 ++++++++++++++++++++++++++-----------------
> 1 files changed, 42 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index ef18348..1464c1e 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -23,6 +23,40 @@
>
> #define MMC_OPS_TIMEOUT_MS (10 * 60 * 1000) /* 10 minute timeout */
>
> +static inline int __mmc_send_status(struct mmc_card *card, u32 *status,
> + bool ignore_crc)
Is there any specific reason to you made this function inline?
> +{
> + int err;
> + struct mmc_command cmd = {0};
> +
> + BUG_ON(!card);
> + BUG_ON(!card->host);
> +
> + cmd.opcode = MMC_SEND_STATUS;
> + if (!mmc_host_is_spi(card->host))
> + cmd.arg = card->rca << 16;
> + cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
> + if (ignore_crc)
> + cmd.flags &= ~MMC_RSP_CRC;
> +
> + err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
> + if (err)
> + return err;
> +
> + /* NOTE: callers are required to understand the difference
> + * between "native" and SPI format status words!
> + */
> + if (status)
> + *status = cmd.resp[0];
> +
> + return 0;
> +}
> +
> +int mmc_send_status(struct mmc_card *card, u32 *status)
> +{
> + return __mmc_send_status(card, status, false);
> +}
> +
> static int _mmc_select_card(struct mmc_host *host, struct mmc_card *card)
> {
> int err;
> @@ -380,6 +414,7 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index,
> u8 value,
> struct mmc_command cmd = {0};
> unsigned long timeout;
> u32 status;
> + bool ignore_crc;
>
> BUG_ON(!card);
> BUG_ON(!card->host);
> @@ -408,10 +443,15 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8
> index, u8 value,
> if (!use_busy_signal)
> return 0;
>
> - /* Must check status to be sure of no errors */
> + /*
> + * Must check status to be sure of no errors
> + * If CMD13 is to check the busy completion of the timing change,
> + * disable the check of CRC error.
> + */
> + ignore_crc = (index == EXT_CSD_HS_TIMING) ? true : false;
You need to consider MMC_CAP_WAIT_WHILE_BUSY in the condition for
"ignore_crc" as well. Otherwise you will ignore CRC in cases where we
actually can detect it.
Kind regards
Ulf Hansson
> timeout = jiffies + msecs_to_jiffies(MMC_OPS_TIMEOUT_MS);
> do {
> - err = mmc_send_status(card, &status);
> + err = __mmc_send_status(card, &status, ignore_crc);
> if (err)
> return err;
> if (card->host->caps & MMC_CAP_WAIT_WHILE_BUSY)
> @@ -449,32 +489,6 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index,
> u8 value,
> }
> EXPORT_SYMBOL_GPL(mmc_switch);
>
> -int mmc_send_status(struct mmc_card *card, u32 *status)
> -{
> - int err;
> - struct mmc_command cmd = {0};
> -
> - BUG_ON(!card);
> - BUG_ON(!card->host);
> -
> - cmd.opcode = MMC_SEND_STATUS;
> - if (!mmc_host_is_spi(card->host))
> - cmd.arg = card->rca << 16;
> - cmd.flags = MMC_RSP_SPI_R2 | MMC_RSP_R1 | MMC_CMD_AC;
> -
> - err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
> - if (err)
> - return err;
> -
> - /* NOTE: callers are required to understand the difference
> - * between "native" and SPI format status words!
> - */
> - if (status)
> - *status = cmd.resp[0];
> -
> - return 0;
> -}
> -
> static int
> mmc_send_bus_test(struct mmc_card *card, struct mmc_host *host, u8 opcode,
> u8 len)
> --
> 1.7.0.4
>
>
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