Re: [PATCH v8 1/2] mmc: add packed command feature of eMMC4.5

[Chris Ball <cjb@laptop.org>]

Hi,

On Fri, Jun 29 2012, Seungwon Jeon wrote:
> This patch adds packed command feature of eMMC4.5.
> The maximum number for packing read(or write) is offered
> and exception event relevant to packed command which is
> used for error handling is enabled. If host wants to use
> this feature, MMC_CAP2_PACKED_CMD should be set.
>
> Signed-off-by: Seungwon Jeon <tgih.jun@samsung.com>
> Reviewed-by: Maya Erez <merez@codeaurora.org>
> Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
> Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
> ---
>  drivers/mmc/core/mmc.c   |   25 +++++++++++++++++++++++++
>  include/linux/mmc/card.h |    3 +++
>  include/linux/mmc/host.h |    4 ++++
>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>  4 files changed, 47 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 258b203..bfb271f 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -516,6 +516,11 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
>  		} else {
>  			card->ext_csd.data_tag_unit_size = 0;
>  		}
> +
> +		card->ext_csd.max_packed_writes =
> +			ext_csd[EXT_CSD_MAX_PACKED_WRITES];
> +		card->ext_csd.max_packed_reads =
> +			ext_csd[EXT_CSD_MAX_PACKED_READS];
>  	} else {
>  		card->ext_csd.data_sector_size = 512;
>  	}
> @@ -1246,6 +1251,26 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>  		}
>  	}
>  
> +	if ((host->caps2 & MMC_CAP2_PACKED_WR &&
> +			card->ext_csd.max_packed_writes > 0) ||
> +	    (host->caps2 & MMC_CAP2_PACKED_RD &&
> +			card->ext_csd.max_packed_reads > 0)) {
> +		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> +				EXT_CSD_EXP_EVENTS_CTRL,
> +				EXT_CSD_PACKED_EVENT_EN,
> +				card->ext_csd.generic_cmd6_time);

Sorry, I don't have a copy of the eMMC 4.5 spec -- is PACKED_EVENT_EN
a one-time programmable fuse on the eMMC, like BKOPS_ENABLE was?

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child