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SubjectRe: [PATCH v7 1/3] mmc: core: Add packed command feature of eMMC4.5
On Mon, Jun 11, 2012 at 1:53 PM, Seungwon Jeon <tgih.jun@samsung.com> 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>

Can you please post some clear performance benchmarks with your patchset ?
Given that #merez claims to see a significant performance drop for
reads, it will be
good to compare notes.
If it's not too much trouble, both CFQ and deadline scheduler figures
would be useful, on a
set of read only, write only and parallel read write usecases.

I can also try to replicate your results if you can publish the exact
configuration you used
for testing (example: iozone parameters)

> ---
>  drivers/mmc/core/mmc.c   |   24 ++++++++++++++++++++++++
>  include/linux/mmc/card.h |    3 +++
>  include/linux/mmc/host.h |    4 ++++
>  include/linux/mmc/mmc.h  |   15 +++++++++++++++
>  4 files changed, 46 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 258b203..f9d54b0 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 +1251,25 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
>                }
>        }
>
> +       if ((host->caps2 & MMC_CAP2_PACKED_CMD) &&
> +                       ((card->ext_csd.max_packed_writes > 0) ||
> +                       (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);
> +               if (err && err != -EBADMSG)
> +                       goto free_card;
> +               if (err) {
> +                       pr_warning("%s: Enabling packed event failed\n",
> +                                       mmc_hostname(card->host));
> +                       card->ext_csd.packed_event_en = 0;
> +                       err = 0;
> +               } else {
> +                       card->ext_csd.packed_event_en = 1;
> +               }
> +       }
> +
>        if (!oldcard)
>                host->card = card;
>
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index d76513b..4aeb4e9 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -53,6 +53,9 @@ struct mmc_ext_csd {
>        u8                      part_config;
>        u8                      cache_ctrl;
>        u8                      rst_n_function;
> +       u8                      max_packed_writes;
> +       u8                      max_packed_reads;
> +       u8                      packed_event_en;
>        unsigned int            part_time;              /* Units: ms */
>        unsigned int            sa_timeout;             /* Units: 100ns */
>        unsigned int            generic_cmd6_time;      /* Units: 10ms */
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 0707d22..9d0d946 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -238,6 +238,10 @@ struct mmc_host {
>  #define MMC_CAP2_BROKEN_VOLTAGE        (1 << 7)        /* Use the broken voltage */
>  #define MMC_CAP2_DETECT_ON_ERR (1 << 8)        /* On I/O err check card removal */
>  #define MMC_CAP2_HC_ERASE_SZ   (1 << 9)        /* High-capacity erase size */
> +#define MMC_CAP2_PACKED_RD     (1 << 10)       /* Allow packed read */
> +#define MMC_CAP2_PACKED_WR     (1 << 11)       /* Allow packed write */
> +#define MMC_CAP2_PACKED_CMD    (MMC_CAP2_PACKED_RD | \
> +                                MMC_CAP2_PACKED_WR) /* Allow packed commands */
>
>        mmc_pm_flag_t           pm_caps;        /* supported pm features */
>        unsigned int        power_notify_type;
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index d425cab..254901a 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -139,6 +139,7 @@ static inline bool mmc_op_multi(u32 opcode)
>  #define R1_CURRENT_STATE(x)    ((x & 0x00001E00) >> 9) /* sx, b (4 bits) */
>  #define R1_READY_FOR_DATA      (1 << 8)        /* sx, a */
>  #define R1_SWITCH_ERROR                (1 << 7)        /* sx, c */
> +#define R1_EXP_EVENT           (1 << 6)        /* sr, a */
>  #define R1_APP_CMD             (1 << 5)        /* sr, c */
>
>  #define R1_STATE_IDLE  0
> @@ -274,6 +275,10 @@ struct _mmc_csd {
>  #define EXT_CSD_FLUSH_CACHE            32      /* W */
>  #define EXT_CSD_CACHE_CTRL             33      /* R/W */
>  #define EXT_CSD_POWER_OFF_NOTIFICATION 34      /* R/W */
> +#define EXT_CSD_PACKED_FAILURE_INDEX   35      /* RO */
> +#define EXT_CSD_PACKED_CMD_STATUS      36      /* RO */
> +#define EXT_CSD_EXP_EVENTS_STATUS      54      /* RO, 2 bytes */
> +#define EXT_CSD_EXP_EVENTS_CTRL        56      /* R/W, 2 bytes */
>  #define EXT_CSD_DATA_SECTOR_SIZE       61      /* R */
>  #define EXT_CSD_GP_SIZE_MULT           143     /* R/W */
>  #define EXT_CSD_PARTITION_ATTRIBUTE    156     /* R/W */
> @@ -318,6 +323,8 @@ struct _mmc_csd {
>  #define EXT_CSD_CACHE_SIZE             249     /* RO, 4 bytes */
>  #define EXT_CSD_TAG_UNIT_SIZE          498     /* RO */
>  #define EXT_CSD_DATA_TAG_SUPPORT       499     /* RO */
> +#define EXT_CSD_MAX_PACKED_WRITES      500     /* RO */
> +#define EXT_CSD_MAX_PACKED_READS       501     /* RO */
>  #define EXT_CSD_HPI_FEATURES           503     /* RO */
>
>  /*
> @@ -377,6 +384,14 @@ struct _mmc_csd {
>  #define EXT_CSD_PWR_CL_4BIT_MASK       0x0F    /* 8 bit PWR CLS */
>  #define EXT_CSD_PWR_CL_8BIT_SHIFT      4
>  #define EXT_CSD_PWR_CL_4BIT_SHIFT      0
> +
> +#define EXT_CSD_PACKED_EVENT_EN        (1 << 3)
> +
> +#define EXT_CSD_PACKED_FAILURE (1 << 3)
> +
> +#define EXT_CSD_PACKED_GENERIC_ERROR   (1 << 0)
> +#define EXT_CSD_PACKED_INDEXED_ERROR   (1 << 1)
> +
>  /*
>  * MMC_SWITCH access modes
>  */
> --
> 1.7.0.4
>
>
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