Hi Venkat,
>>> +static void mmc_send_bkops_cmd(struct mmc_card *card)
>>> +{
>>> + int err;
>>> +
>>> + BUG_ON(!card);
>>> +
>>> + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>>> + EXT_CSD_BKOPS_START, 1, 0);
>>> + if (err) {
>>> + pr_warning("%s: error %d starting bkops\n",
>>> + mmc_hostname(card->host), err);
>>> + mmc_card_clr_need_bkops(card);
>>> + return;
>>> + }
>>> +
>>> + mmc_card_clr_need_bkops(card);
>>> + mmc_card_set_doing_bkops(card);
>>> +
>>> +}
>>> +
>>> +void mmc_start_periodic_bkops(struct work_struct *work)
>>
>> There's nothing periodic about this function, by looking at the contents.
>> Maybe this one should be called mmc_start_bkops ..
>
> Well...i will checked this point..i tested with eMMC4.5 card...In my case,
> working this function.
> But in your case, didn't work nothing..i will rework to this point after
> debugging.
Could you explain more detail? In my case, it's working at every 5sec.
>
>>
>>> +{
>>> + struct mmc_host *host = container_of(work, struct mmc_host,
>>> + start_bkops.work);
>>> +
>>> + mmc_card_set_check_bkops(host->card);
>> Why is this being set here. The condition should be in the caller context.
We need to read bkops-status register. so card is set to check-bkops.
>>
>>> +
>>> + mmc_claim_host(host);
>>> + mmc_start_bkops(host->card);
>>> + mmc_release_host(host);
>>> +}
>>> +EXPORT_SYMBOL(mmc_start_periodic_bkops);
>>> +
>>> +/**
>>> + * mmc_start_bkops - start BKOPS for supported cards
>>> + * @card: MMC card to start BKOPS
>>> + *
>>> + * Start background operations whenever requested.
>>> + * when the urgent BKOPS bit is set in a R1 command response
>>> + * then background operations should be started immediately.
>>> +*/
>>> +void mmc_start_bkops(struct mmc_card *card)
>>
>> .. and this one should be called __mmc_start_bkops() ?
>
> Sure..i will change that.
>
>>
>>> +{
>>> + BUG_ON(!card);
>>> + if (!card->ext_csd.bkops_en || !(card->host->caps2 &
>>> MMC_CAP2_BKOPS))
>>> + return;
>>> +
>>> + if (mmc_card_check_bkops(card)) {
>>> + mmc_card_clr_check_bkops(card);
>>> + if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS)) {
>>> + if (card->ext_csd.raw_bkops_status)
>>> + mmc_card_set_need_bkops(card);
>>
>> This breaks abstraction. Why check ext_csd even after URGENT_BKOPS is set ?
>
> You means that need not to check ext_csd?
> Well I didn't think so, we need to check bkops-status register
When URGENT_BKOPS is triggered, we didn't know which level.
It's just guessing Level-3 or Level-2.
In my case, status should be level-1 or level-0.
>
>>
>>> + } else
>>> + mmc_card_clr_need_bkops(card);
>>> + }
>>> +
>>> + /*
>>> + * If card_need_bkops_flag didn't set, then do nothing just
>>> + * return
>>> + */
>>> + if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
>>> + goto check_bkops;
>>> +
>>> + mmc_send_bkops_cmd(card);
>>> +
>>> +check_bkops:
>>> + queue_delayed_work(system_nrt_wq, &card->host->start_bkops, 5 * HZ);
>>
>> IIUC, queue_delayed_work->start_bkops = mmc_start_periodic_bkops ->
>> mmc_start_bkops -> queue_delayed_work
>> .. ad infinitum ?
If required the request, then it should be stopped.
>
> Actually, i want to get review for this point..How did you think about?
>
>>
>>> +}
>>> +EXPORT_SYMBOL(mmc_start_bkops);
>>> +
>>> static void mmc_wait_done(struct mmc_request *mrq)
>>> {
>>> complete(&mrq->completion);
>>> @@ -348,8 +425,10 @@ struct mmc_async_req *mmc_start_req(struct mmc_host
>>> *host,
>>> struct mmc_async_req *data = host->areq;
>>>
>>> /* Prepare a new request */
>>> - if (areq)
>>> + if (areq) {
>>> + cancel_delayed_work_sync(&host->start_bkops);
>>> mmc_pre_req(host, areq->mrq, !host->areq);
>>> + }
>>>
>>> if (host->areq) {
>>> mmc_wait_for_req_done(host, host->areq->mrq);
>>> @@ -359,8 +438,11 @@ struct mmc_async_req *mmc_start_req(struct mmc_host
>>> *host,
>>> if (!err && areq)
>>> start_err = __mmc_start_req(host, areq->mrq);
>>>
>>> - if (host->areq)
>>> + if (host->areq) {
>>> mmc_post_req(host, host->areq->mrq, 0);
>>> + if (!areq && host->areq && mmc_card_mmc(host->card))
>>> + mmc_start_bkops(host->card);
>>> + }
>>>
>>> /* Cancel a prepared request if it was not started. */
>>> if ((err || start_err) && areq)
>>> @@ -480,6 +562,84 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct
>>> mmc_command *cmd, int retries
>>> EXPORT_SYMBOL(mmc_wait_for_cmd);
>>>
>>> /**
>>> + * mmc_stop_bkops - stop ongoing BKOPS
>>> + * @card: MMC card to check BKOPS
>>> + *
>>> + * Send HPI command to interrupt ongoing background operations,
>>> + * to allow rapid servicing of foreground operations,e.g. read/
>>> + * writes. Wait until the card comes out of the programming state
>>> + * to avoid errors in servicing read/write requests.
>>> + */
>>> +int mmc_stop_bkops(struct mmc_card *card)
>>> +{
>>> + int err = 0;
>>> + unsigned int timeout = 0x10000;
>>> + u32 status;
>>> +
>>> + BUG_ON(!card);
>>> + cancel_delayed_work_sync(&card->host->start_bkops);
>>> +
>>> + if (card->ext_csd.raw_bkops_status == EXT_CSD_BKOPS_LEVEL_3) {
>>> + do {
>>> + if (timeout == 0)
>>> + break;
>>> + mmc_claim_host(card->host);
>>> + mmc_send_status(card, &status);
>>> + mmc_release_host(card->host);
>>> +
>>> + timeout--;
>>> + } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
>>> + if (timeout != 0)
>>> + goto done;
>>> + }
>>
>> This won't necessarily work all the time. Once BKOPS_START is issued, the
>> card
>> might finish GC and move to transfer state even before HPI can be sent.
>> So just exit if the card is in transfer state already.
>
> Right..But if didn't wait for prog-done, we can issue the HPI.
> (If didn't use Busy waiting flag)
>
>>
>> In this context, kdorfman's comments on "mmc:fix HPI execution
>> sequence" makes sense.
>>
>>> +
>>> + err = mmc_interrupt_hpi(card);
>>> +
>>> +done:
>>> + mmc_card_clr_doing_bkops(card);
>>> +
>>> + return err;
>>> +}
>>> +EXPORT_SYMBOL(mmc_stop_bkops);
>>> +
>>> +int mmc_read_bkops_status(struct mmc_card *card)
>>> +{
>>> + int err;
>>> + u8 ext_csd[512];
>>> +
>>> + mmc_claim_host(card->host);
>>> + err = mmc_send_ext_csd(card, ext_csd);
>>> + mmc_release_host(card->host);
>>> + if (err)
>>> + return err;
>>> +
>>> + card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
>>> + card->ext_csd.raw_exception_status =
>>> ext_csd[EXT_CSD_EXCEPTION_STATUS];
>>> +
>>> + return 0;
>>> +}
>>> +EXPORT_SYMBOL(mmc_read_bkops_status);
>>> +
>>> +int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
>>> +{
>>> + int err;
>>> +
>>> + err = mmc_read_bkops_status(card);
>>> + if (err) {
>>> + pr_err("%s: Didn't read bkops status : %d\n",
>>> + mmc_hostname(card->host), err);
>>> + return 0;
>>> + }
>>> +
>>> + /* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
>>> + if (card->ext_csd.rev == 5)
>>> + return 1;
>>
>> Please swap the order in which you are doing this.
>> For eMMC4.41, we can save the mmc_read_bkops_status atleast for 4.41 card
>> for _every_ request, which is not used.
>
> If card is eMMC4.41, how did you check bkops-status?
> In eMCM4.41, also check the bkops-status level.
>
>>
>>> +
>>> + return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
>>> +}
>>> +EXPORT_SYMBOL(mmc_is_exception_event);
>>> +
>>> +/**
>>> * mmc_set_data_timeout - set the timeout for a data command
>>> * @data: data phase for command
>>> * @card: the MMC card associated with the data transfer
>>> @@ -2382,6 +2542,12 @@ int mmc_pm_notify(struct notifier_block
>>> *notify_block,
>>> switch (mode) {
>>> case PM_HIBERNATION_PREPARE:
>>> case PM_SUSPEND_PREPARE:
>>> + if (host->card && mmc_card_mmc(host->card) &&
>>> + mmc_card_doing_bkops(host->card)) {
>>> + mmc_interrupt_hpi(host->card);
>>> + mmc_card_clr_doing_bkops(host->card);
>>> + }
>>> + cancel_delayed_work_sync(&host->start_bkops);
>>>
>>> spin_lock_irqsave(&host->lock, flags);
>>> host->rescan_disable = 1;
>>> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
>>> index 91c84c7..3b6a8e4 100644
>>> --- a/drivers/mmc/core/host.c
>>> +++ b/drivers/mmc/core/host.c
>>> @@ -330,6 +330,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct
>>> device *dev)
>>> spin_lock_init(&host->lock);
>>> init_waitqueue_head(&host->wq);
>>> INIT_DELAYED_WORK(&host->detect, mmc_rescan);
>>> + INIT_DELAYED_WORK(&host->start_bkops, mmc_start_periodic_bkops);
>>> #ifdef CONFIG_PM
>>> host->pm_notify.notifier_call = mmc_pm_notify;
>>> #endif
>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>> index 2f0e11c..275555a 100644
>>> --- a/drivers/mmc/core/mmc.c
>>> +++ b/drivers/mmc/core/mmc.c
>>> @@ -463,6 +463,24 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8
>>> *ext_csd)
>>> }
>>>
>>> if (card->ext_csd.rev >= 5) {
>>> + /* check whether the eMMC card support BKOPS */
>>> + if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
>>> + card->ext_csd.bkops = 1;
>>> + card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
>>> + card->ext_csd.raw_bkops_status =
>>> + ext_csd[EXT_CSD_BKOPS_STATUS];
>>> + if (!card->ext_csd.bkops_en &&
>>> + card->host->caps2 & MMC_CAP2_INIT_BKOPS) {
>>> + err = mmc_switch(card,
>>> EXT_CSD_CMD_SET_NORMAL,
>>> + EXT_CSD_BKOPS_EN, 1, 0);
>>
>> I am not too comfortable tying a OTP register setting to a host
>> controller capability.
>> What if I had multiple instances of MMC and reuse the same HC, and
>> each needs a different
>> setting ? Or the same HC used in multiple SoCs ?
>> A sysfs entry would be better - program the INIT when a user
>> explicitly sets "enable_bkops" for the device
>> that is being used.
>
> Actually, at first time i didn't consider whether bkops is enabled or not.
> Some card can be disabled for bkops enable bit.
> If INIT_BKOPS is set, user didn't consider whether bkops is enabled or not.
> because that's set to enable.
> Right, this is used sysfs..but I think it's problem what is prefrence..
>
>>
>>> + if (err)
>>> + pr_warning("%s: Enabling BKOPS
>>> failed\n",
>>> + mmc_hostname(card->host));
>>> + else
>>> + card->ext_csd.bkops_en = 1;
>>> + }
>>> + }
>>> +
>>> /* check whether the eMMC card supports HPI */
>>> if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
>>> card->ext_csd.hpi = 1;
>>> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
>>> index 69370f4..bc8da17 100644
>>> --- a/drivers/mmc/core/mmc_ops.c
>>> +++ b/drivers/mmc/core/mmc_ops.c
>>> @@ -399,6 +399,10 @@ int mmc_switch(struct mmc_card *card, u8 set, u8
>>> index, u8 value,
>>> if (err)
>>> return err;
>>>
>>> + /* No need to check card status in case of BKOPS switch*/
>>> + if (index == EXT_CSD_BKOPS_START)
>>> + return 0;
>>> +
>>> /* Must check status to be sure of no errors */
>>> do {
>>> err = mmc_send_status(card, &status);
>>> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
>>> index d76513b..52b507d 100644
>>> --- a/include/linux/mmc/card.h
>>> +++ b/include/linux/mmc/card.h
>>> @@ -76,6 +76,9 @@ struct mmc_ext_csd {
>>> bool hpi_en; /* HPI enablebit */
>>> bool hpi; /* HPI support bit */
>>> unsigned int hpi_cmd; /* cmd used as HPI */
>>> + bool bkops; /* background support bit */
>>> + bool bkops_en; /* background enable bit */
>>> + u8 raw_exception_status; /* 53 */
>>> unsigned int data_sector_size; /* 512 bytes or 4KB
>>> */
>>> unsigned int data_tag_unit_size; /* DATA TAG UNIT
>>> size */
>>> unsigned int boot_ro_lock; /* ro lock support */
>>> @@ -93,6 +96,7 @@ struct mmc_ext_csd {
>>> u8 raw_sec_erase_mult; /* 230 */
>>> u8 raw_sec_feature_support;/* 231 */
>>> u8 raw_trim_mult; /* 232 */
>>> + u8 raw_bkops_status; /* 246 */
>>> u8 raw_sectors[4]; /* 212 - 4 bytes */
>>>
>>> unsigned int feature_support;
>>> @@ -225,6 +229,9 @@ struct mmc_card {
>>> #define MMC_CARD_REMOVED (1<<7) /* card has been removed */
>>> #define MMC_STATE_HIGHSPEED_200 (1<<8) /* card is in HS200
>>> mode */
>>> #define MMC_STATE_SLEEP (1<<9) /* card is in sleep
>>> state */
>>> +#define MMC_STATE_NEED_BKOPS (1<<10) /* card need to do BKOPS */
>>> +#define MMC_STATE_DOING_BKOPS (1<<11) /* card is doing BKOPS */
>>> +#define MMC_STATE_CHECK_BKOPS (1<<12) /* card need to check BKOPS
>>> */
>>> unsigned int quirks; /* card quirks */
>>> #define MMC_QUIRK_LENIENT_FN0 (1<<0) /* allow SDIO FN0 writes
>>> outside of the VS CCCR range */
>>> #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1) /* use func->cur_blksize */
>>> @@ -391,6 +398,9 @@ static inline void __maybe_unused remove_quirk(struct
>>> mmc_card *card, int data)
>>> #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
>>> #define mmc_card_removed(c) ((c) && ((c)->state & MMC_CARD_REMOVED))
>>> #define mmc_card_is_sleep(c) ((c)->state & MMC_STATE_SLEEP)
>>> +#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
>>> +#define mmc_card_doing_bkops(c) ((c)->state & MMC_STATE_DOING_BKOPS)
>>> +#define mmc_card_check_bkops(c) ((c)->state & MMC_STATE_CHECK_BKOPS)
>>>
>>> #define mmc_card_set_present(c) ((c)->state |= MMC_STATE_PRESENT)
>>> #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
>>> @@ -403,7 +413,13 @@ static inline void __maybe_unused remove_quirk(struct
>>> mmc_card *card, int data)
>>> #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
>>> #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
>>> #define mmc_card_set_sleep(c) ((c)->state |= MMC_STATE_SLEEP)
>>> +#define mmc_card_set_need_bkops(c) ((c)->state |= MMC_STATE_NEED_BKOPS)
>>> +#define mmc_card_set_doing_bkops(c) ((c)->state |=
>>> MMC_STATE_DOING_BKOPS)
>>> +#define mmc_card_set_check_bkops(c) ((c)->state |= MMC_STATE_CHECK_BKOPS)
>>>
>>> +#define mmc_card_clr_need_bkops(c) ((c)->state &=
>>> ~MMC_STATE_NEED_BKOPS)
>>> +#define mmc_card_clr_doing_bkops(c) ((c)->state &=
>>> ~MMC_STATE_DOING_BKOPS)
>>> +#define mmc_card_clr_check_bkops(c) ((c)->state &= ~MMC_STATE_CHECK_BKOPS)
>>> #define mmc_card_clr_sleep(c) ((c)->state &= ~MMC_STATE_SLEEP)
>>> /*
>>> * Quirk add/remove for MMC products.
>>> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
>>> index 1b431c7..c920250 100644
>>> --- a/include/linux/mmc/core.h
>>> +++ b/include/linux/mmc/core.h
>>> @@ -134,6 +134,9 @@ struct mmc_host;
>>> struct mmc_card;
>>> struct mmc_async_req;
>>>
>>> +extern int mmc_stop_bkops(struct mmc_card *);
>>> +extern int mmc_read_bkops_status(struct mmc_card *);
>>> +extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
>>> extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
>>> struct mmc_async_req *, int *);
>>> extern int mmc_interrupt_hpi(struct mmc_card *);
>>> @@ -163,6 +166,8 @@ extern int mmc_can_sanitize(struct mmc_card *card);
>>> extern int mmc_can_secure_erase_trim(struct mmc_card *card);
>>> extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int
>>> from,
>>> unsigned int nr);
>>> +extern void mmc_start_periodic_bkops(struct work_struct *work);
>>> +extern void mmc_start_bkops(struct mmc_card *card);
>>> extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
>>>
>>> extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
>>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>>> index 0707d22..186d146 100644
>>> --- a/include/linux/mmc/host.h
>>> +++ b/include/linux/mmc/host.h
>>> @@ -238,6 +238,8 @@ 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_INIT_BKOPS (1 << 10) /* To enable BKOPS */
>>> +#define MMC_CAP2_BKOPS (1 << 11) /* BKOPS supported */
>>>
>>> mmc_pm_flag_t pm_caps; /* supported pm features */
>>> unsigned int power_notify_type;
>>> @@ -320,6 +322,8 @@ struct mmc_host {
>>>
>>> unsigned int actual_clock; /* Actual HC clock rate */
>>>
>>> + struct delayed_work start_bkops; /* Periodic bkops start */
>>> +
>>> unsigned long private[0] ____cacheline_aligned;
>>> };
>>>
>>> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
>>> index d425cab..06afeb4 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_EXCEPTION_EVENT (1 << 6) /* sx, a */
>>> #define R1_APP_CMD (1 << 5) /* sr, c */
>>>
>>> #define R1_STATE_IDLE 0
>>> @@ -274,12 +275,15 @@ 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_EXCEPTION_STATUS 54 /* RO */
>>> #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 */
>>> #define EXT_CSD_PARTITION_SUPPORT 160 /* RO */
>>> #define EXT_CSD_HPI_MGMT 161 /* R/W */
>>> #define EXT_CSD_RST_N_FUNCTION 162 /* R/W */
>>> +#define EXT_CSD_BKOPS_EN 163 /* R/W */
>>> +#define EXT_CSD_BKOPS_START 164 /* W */
>>> #define EXT_CSD_SANITIZE_START 165 /* W */
>>> #define EXT_CSD_WR_REL_PARAM 166 /* RO */
>>> #define EXT_CSD_BOOT_WP 173 /* R/W */
>>> @@ -313,11 +317,13 @@ struct _mmc_csd {
>>> #define EXT_CSD_PWR_CL_200_360 237 /* RO */
>>> #define EXT_CSD_PWR_CL_DDR_52_195 238 /* RO */
>>> #define EXT_CSD_PWR_CL_DDR_52_360 239 /* RO */
>>> +#define EXT_CSD_BKOPS_STATUS 246 /* RO */
>>> #define EXT_CSD_POWER_OFF_LONG_TIME 247 /* RO */
>>> #define EXT_CSD_GENERIC_CMD6_TIME 248 /* RO */
>>> #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_BKOPS_SUPPORT 502 /* RO */
>>> #define EXT_CSD_HPI_FEATURES 503 /* RO */
>>>
>>> /*
>>> @@ -386,4 +392,18 @@ struct _mmc_csd {
>>> #define MMC_SWITCH_MODE_CLEAR_BITS 0x02 /* Clear bits which are 1
>>> in value */
>>> #define MMC_SWITCH_MODE_WRITE_BYTE 0x03 /* Set target to value */
>>>
>>> +/*
>>> + * BKOPS status level
>>> + */
>>> +#define EXT_CSD_BKOPS_LEVEL_2 0x2
>>> +#define EXT_CSD_BKOPS_LEVEL_3 0x3
>>> +
>>> +/*
>>> + * EXCEPTION_EVENT_STATUS field (eMMC4.5)
>>> + */
>>> +#define EXT_CSD_URGENT_BKOPS BIT(0)
>>> +#define EXT_CSD_DYNCAP_NEEDED BIT(1)
>>> +#define EXT_CSD_SYSPOOL_EXHAUSTED BIT(2)
>>> +#define EXT_CSD_PACKED_FAILURE BIT(3)
>>> +
>>> #endif /* LINUX_MMC_MMC_H */
>>
>>
>> Overall, my significant concern is about performance.
>> IIUC, There is a ext_csd query during the execution of _every_ request
>> - this is far too obsessive and could kill throughput.
>
> I didn't find the performance issue. didn't _every_ request..only check to
> set bkops_need_check.
>
>> A more pragmatic approach would be to trigger on a threshold of number
>> of writes or discards (ex: After 1M sector writes)
In this case, we need to use bkops feature, I think that just using discard.
How think about? if you have other opinion, let me know, plz.
Then i will apply to next-patch.
Best Regards,
Jaehoon Chung
>
> I will try to this approach.
>
>> This means that a predominantly read only disk, which wouldn't need
>> any BKOPS, wouldn't have any overhead.
>>
>> Let me know if my assumption is incorrect.
>
> Thanks for reviwe.
>
> Best Regards,
> Jaehoon Chung
>
>>
>> ~Venkat.
>> --
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>>
>
>
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