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SubjectRe: [PATCH v3 1/1]mmc: implemented eMMC4.4 enhanced area feature
Hi Chuanxiao,

On Thu, Jan 20, 2011 at 03:55:56PM +0800, Chuanxiao Dong wrote:
> Enhanced area feature is a new feature defined in eMMC4.4 standard. This
> kind of area can help to improve the performance.
>
> MMC driver will read out the enhanced area offset and size and add them
> to be device attributes. The feature enabling should be done in manufactory.
> To use this feature, bit ERASE_GRP_DEF should also be set.
>
> Documentation/ABI/testing/sysfs-devices-mmc described the two new attributes
>
> Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
> ---
> Documentation/ABI/testing/sysfs-devices-mmc | 19 ++++++
> drivers/mmc/core/mmc.c | 80 +++++++++++++++++++++++++++
> include/linux/mmc/card.h | 3 +
> include/linux/mmc/mmc.h | 3 +
> 4 files changed, 105 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-devices-mmc
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-mmc b/Documentation/ABI/testing/sysfs-devices-mmc
> new file mode 100644
> index 0000000..6e759ae
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-devices-mmc
> @@ -0,0 +1,19 @@
> +What: /sys/devices/.../mmc_host/mmcX/mmcX:XXXX/enhanced_area_offset
> +Date: January 2011
> +Contact: Chuanxiao Dong <chuanxiao.dong@intel.com>
> +Description:
> + Enhanced area is a new feature defined in eMMC4.4 standard.eMMC4.4 or
> + later card can support such feature. This kind of area can help to
> + improve the card performance. If the feature is enabled, this attribute
> + will indicate the start address of enhanced data area. If not, this
> + attribute will be -EINVAL. Unit Byte. Format decimal.
> +
> +What: /sys/devices/.../mmc_host/mmcX/mmcX:XXXX/enhanced_area_size
> +Date: January 2011
> +Contact: Chuanxiao Dong <chuanxiao.dong@intel.com>
> +Description:
> + Enhanced area is a new feature defined in eMMC4.4 standard. eMMC4.4 or
> + later card can support such feature. This kind of area can help to
> + improve the card performance. If the feature is enabled, this attribute
> + will indicate the size of enhanced data area. If not, this attribute
> + will be -EINVAL. Unit KByte. Format decimal.

This is still wrapped at > 80 columns.

> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 16006ef..5ab44bb 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -302,6 +302,48 @@ static int mmc_read_ext_csd(struct mmc_card *card)
> }
>
> if (card->ext_csd.rev >= 4) {
> + /*
> + * Enhanced area feature support
> + * check whether eMMC card has the Enhanced area enabled.
> + * if so, export enhanced area offset and size to
> + * user by adding sysfs interface
> + */
> + if ((ext_csd[EXT_CSD_PARTITION_SUPPORT] & 0x2) &&
> + (ext_csd[EXT_CSD_PARTITION_ATTRIBUTE] & 0x1)) {
> + u8 hc_erase_grp_sz =
> + ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE];
> + u8 hc_wp_grp_sz =
> + ext_csd[EXT_CSD_HC_WP_GRP_SIZE];
> + /*
> + * set a flag to identify whether the enhanced
> + * user data is enabled
> + */
> + card->ext_csd.enhanced_area_en = 1;
> + /*
> + * calculate the enhanced data area offset, unit B
> + */
> + card->ext_csd.enhanced_area_offset =
> + (ext_csd[139] << 24) + (ext_csd[138] << 16) +
> + (ext_csd[137] << 8) + ext_csd[136];
> + if (mmc_card_blockaddr(card))
> + card->ext_csd.enhanced_area_offset <<= 9;
> + /*
> + * calculate the enhanced data area size, unit KB
> + */
> + card->ext_csd.enhanced_area_size =
> + (ext_csd[142] << 16) + (ext_csd[141] << 8) +
> + ext_csd[140];
> + card->ext_csd.enhanced_area_size *=
> + (size_t)(hc_erase_grp_sz * hc_wp_grp_sz);
> + card->ext_csd.enhanced_area_size <<= 9;
> + } else {
> + /*
> + * If not enabled enhanced area, disable these
> + * device attributes
> + */
> + card->ext_csd.enhanced_area_offset = -EINVAL;
> + card->ext_csd.enhanced_area_size = -EINVAL;
> + }
> card->ext_csd.sec_trim_mult =
> ext_csd[EXT_CSD_SEC_TRIM_MULT];
> card->ext_csd.sec_erase_mult =
> @@ -336,6 +378,9 @@ MMC_DEV_ATTR(manfid, "0x%06x\n", card->cid.manfid);
> MMC_DEV_ATTR(name, "%s\n", card->cid.prod_name);
> MMC_DEV_ATTR(oemid, "0x%04x\n", card->cid.oemid);
> MMC_DEV_ATTR(serial, "0x%08x\n", card->cid.serial);
> +MMC_DEV_ATTR(enhanced_area_offset, "%lld\n",
> + card->ext_csd.enhanced_area_offset);
> +MMC_DEV_ATTR(enhanced_area_size, "%d\n", card->ext_csd.enhanced_area_size);
>
> static struct attribute *mmc_std_attrs[] = {
> &dev_attr_cid.attr,
> @@ -349,6 +394,8 @@ static struct attribute *mmc_std_attrs[] = {
> &dev_attr_name.attr,
> &dev_attr_oemid.attr,
> &dev_attr_serial.attr,
> + &dev_attr_enhanced_area_offset.attr,
> + &dev_attr_enhanced_area_size.attr,
> NULL,
> };
>
> @@ -484,6 +531,39 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> }
>
> /*
> + * If enhanced_area_en is TRUE, host need to enable
> + * ERASE_GRP_DEF bit.
> + * ERASE_GRP_DEF bit will be lost every time
> + * after a reset or power off.
> + */
> + if (card->ext_csd.enhanced_area_en) {
> + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> + EXT_CSD_ERASE_GROUP_DEF, 1);
> +
> + if (err && err != -EBADMSG)
> + goto free_card;
> +
> + if (err) {
> + err = 0;
> + /*
> + * Just disable enhanced area off & sz
> + * will try to enable ERASE_GROUP_DEF
> + * during next time reinit
> + */
> + card->ext_csd.enhanced_area_offset = -EINVAL;
> + card->ext_csd.enhanced_area_size = -EINVAL;
> + } else {
> + card->ext_csd.erase_group_def = 1;
> + /*
> + * enable ERASE_GRP_DEF successfully.
> + * This will affect the erase size, so
> + * here need to reset erase size
> + */
> + mmc_set_erase_size(card);
> + }
> + }
> +
> + /*
> * Activate high speed (if supported)
> */
> if ((card->ext_csd.hs_max_dtr != 0) &&
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 8ce0827..736697f 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -54,6 +54,9 @@ struct mmc_ext_csd {
> unsigned int sec_trim_mult; /* Secure trim multiplier */
> unsigned int sec_erase_mult; /* Secure erase multiplier */
> unsigned int trim_timeout; /* In milliseconds */
> + bool enhanced_area_en; /* enhanced area en */
> + loff_t enhanced_area_offset; /* enhanced area addr */
> + size_t enhanced_area_size; /* enhanced area size */

Now enhanced_area_en is aligned correctly, but the other two aren't.

This adds a warning:

drivers/mmc/core/mmc.c: In function ‘mmc_enhanced_area_size_show’:
drivers/mmc/core/mmc.c:383:261: warning: format ‘%d’ expects type ‘int’,
but argument 3 has type ‘size_t’

If you really want size_t, you should use %zu for it -- see
Documentation/printk-formats.txt. (Declaring it as unsigned int would
work fine too.)

Oh, and let's mention the units of _offset and _size in the comment in
card.h.

> };
> struct sd_scr {
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 612301f..264ba54 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -253,6 +253,8 @@ struct _mmc_csd {
> * EXT_CSD fields
> */
>
> +#define EXT_CSD_PARTITION_ATTRIBUTE 156 /* R/W */
> +#define EXT_CSD_PARTITION_SUPPORT 160 /* RO */
> #define EXT_CSD_ERASE_GROUP_DEF 175 /* R/W */
> #define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
> #define EXT_CSD_BUS_WIDTH 183 /* R/W */
> @@ -262,6 +264,7 @@ struct _mmc_csd {
> #define EXT_CSD_CARD_TYPE 196 /* RO */
> #define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
> #define EXT_CSD_S_A_TIMEOUT 217 /* RO */
> +#define EXT_CSD_HC_WP_GRP_SIZE 221 /* RO */
> #define EXT_CSD_ERASE_TIMEOUT_MULT 223 /* RO */
> #define EXT_CSD_HC_ERASE_GRP_SIZE 224 /* RO */
> #define EXT_CSD_SEC_TRIM_MULT 229 /* RO */

Thanks,

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