On Mon, July 30, 2012 2:00 am, Jaehoon Chung wrote:
> On 07/29/2012 11:33 AM, Minchan Kim wrote:
>> On Tue, Jul 24, 2012 at 10:56 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>> wrote:
>>> Enable eMMC background operations (BKOPS) feature.
>>>
>>> If URGENT_BKOPS is set after a response, note that BKOPS
>>> are required. Immediately run BKOPS if required.
>>> read/write operations should be requested during BKOPS(LEVEL-1),
>>> then issue HPI to interrupt the ongoing BKOPS
>>> and service the foreground operation.
>>> (This patch is only control the LEVEL2/3.)
>>>
>>> When repeating the writing 1GB data, at a certain time, performance is
>>> decreased.
>>> At that time, card is also triggered the Level-3 or Level-2.
>>> After running bkops, performance is recovered.
>>>
>>> Future considerations
>>> * Check BKOPS_LEVEL=1 and start BKOPS in a preventive manner.
>>> * Interrupt ongoing BKOPS before powering off the card.
>>> * How get BKOPS_STATUS value.(periodically send ext_csd command?)
>>> * If use periodic bkops, also consider runtime_pm control.
>>>
>>> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
>>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>>> Signed-off-by: Konstantin Dorfman <kdorfman@xxxxxxxxxxxxxx>
>>> Signed-off-by: Maya Erez <merez@xxxxxxxxxxxxxx>
>>> ---
>>> Changelog v11:
>>> - removed the MMC_CAP2_BKOPS.
>>> : if card support and enable bkops, then use it.
>>> Changelog v10:
>>> - Based on latest mmc-next
>>> - Only control the level-2/3.
>>> : If triggered upper than level2, immediately start
>>> bkops.
>>> - Remove the BKOPS_CAP2_INIT_BKOPS (move into mmc-util)
>>> - change use_busy_signal instead of waiting_for_prog_done for
>>> __mmc_switch
>>> - Remove the useless code.
>>> - Add the from_exception to prepare the periodic bkops.
>>> Changelog V9:
>>> - Rebased on patch-v7.
>>> - Added Konstantin and Maya's patch
>>> : mmc:core: Define synchronous BKOPS timeout
>>> : mmc:core: eMMC4.5 BKOPS fixes
>>> - Removed periodic bkops
>>> : This feature will do in future work
>>> - Add __mmc_switch() for waiting_for_prod_done.
>>>
>>> Changelog V8:
>>> - Remove host->lock spin lock reviewed by Adrian
>>> - Support periodic start bkops
>>> - when bkops_status is level-3, if timeout is set to 0, send
>>> hpi.
>>> - Move the start-bkops point
>>> Changelog V7:
>>> - Use HPI command when issued URGENT_BKOPS
>>> - Recheck until clearing the bkops-status bit.
>>> Changelog V6:
>>> - Add the flag of check-bkops-status.
>>> (For fixing async_req problem)
>>> - Add the capability for MMC_CAP2_INIT_BKOPS.
>>> (When unset the bkops_en bit in ext_csd register)
>>> - modify the wrong condition.
>>> Changelog V5:
>>> - Rebase based on the latest mmc-next.
>>> - modify codes based-on Chris's comment
>>> Changelog V4:
>>> - Add mmc_read_bkops_status
>>> - When URGENT_BKOPS(level2-3), didn't use HPI command.
>>> - In mmc_switch(), use R1B/R1 according to level.
>>> Changelog V3:
>>> - move the bkops setting's location in mmc_blk_issue_rw_rq
>>> - modify condition checking
>>> - bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
>>> - remove the unused code
>>> - change pr_debug instead of pr_warn in mmc_send_hpi_cmd
>>> - Add the Future consideration suggested by Per
>>> Changelog V2:
>>> - Use EXCEPTION_STATUS instead of URGENT_BKOPS
>>> - Add function to check Exception_status(for eMMC4.5)
>>> ---
>>> drivers/mmc/core/core.c | 145
>>> +++++++++++++++++++++++++++++++++++++++++++-
>>> drivers/mmc/core/mmc.c | 11 +++
>>> drivers/mmc/core/mmc_ops.c | 26 +++++++-
>>> include/linux/mmc/card.h | 8 +++
>>> include/linux/mmc/core.h | 4 +
>>> include/linux/mmc/mmc.h | 19 ++++++
>>> 6 files changed, 207 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>> index 8ac5246..ed2cc93 100644
>>> --- a/drivers/mmc/core/core.c
>>> +++ b/drivers/mmc/core/core.c
>>> @@ -41,6 +41,12 @@
>>> #include "sd_ops.h"
>>> #include "sdio_ops.h"
>>>
>>> +/*
>>> + * The Background operation can take a long time, depends on the house
>>> keeping
>>> + * operations the card has to peform
>>> + */
>>> +#define MMC_BKOPS_MAX_TIMEOUT (4 * 60 * 1000) /* max time to wait in
>>> ms */
>>> +
>>> static struct workqueue_struct *workqueue;
>>> static const unsigned freqs[] = { 400000, 300000, 200000, 100000 };
>>>
>>> @@ -245,6 +251,70 @@ mmc_start_request(struct mmc_host *host, struct
>>> mmc_request *mrq)
>>> host->ops->request(host, mrq);
>>> }
>>>
>>> +/**
>>> + * mmc_start_bkops - start BKOPS for supported cards
>>> + * @card: MMC card to start BKOPS
>>> + * @form_exception: A flags to indicate if this function was
>>> + * called due to an exception raised by the card
>>> + *
>>> + * 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, bool from_exception)
>>> +{
>>> + int err;
>>> + int timeout;
>>> + bool use_busy_signal;
>>> +
>>> + BUG_ON(!card);
>>> +
>>> + if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card))
>>> + return;
>>> +
>>> + err = mmc_read_bkops_status(card);
>>> + if (err) {
>>> + pr_err("%s: Didn't read bkops status : %d\n",
>>> + mmc_hostname(card->host), err);
>>> + return;
>>> + }
>>> +
>>> + if (!card->ext_csd.raw_bkops_status)
>>> + return;
>>> +
>>> + if (card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2
>>> + && (from_exception))
>>> + return;
>>> +
>>> + mmc_claim_host(card->host);
>>> + if (card->ext_csd.raw_bkops_status >= EXT_CSD_BKOPS_LEVEL_2) {
>>> + timeout = MMC_BKOPS_MAX_TIMEOUT;
>>> + use_busy_signal = true;
>>> + } else {
>>> + timeout = 0;
>>> + use_busy_signal = false;
>>> + }
>>> +
>>> + err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>>> + EXT_CSD_BKOPS_START, 1, timeout,
>>> use_busy_signal);
>>> + if (err) {
>>> + pr_warn("%s: error %d starting bkops\n",
>>> + mmc_hostname(card->host), err);
>>> + goto out;
>>> + }
>>> +
>>> + /*
>>> + * For urgent bkops status (LEVEL_2 and more)
>>> + * bkops executed synchronously, otherwise
>>> + * the operation is in progress
>>> + */
>>> + if (!use_busy_signal)
>>> + mmc_card_set_doing_bkops(card);
>>> +out:
>>> + mmc_release_host(card->host);
>>> +}
>>> +EXPORT_SYMBOL(mmc_start_bkops);
>>> +
>>> static void mmc_wait_done(struct mmc_request *mrq)
>>> {
>>> complete(&mrq->completion);
>>> @@ -354,6 +424,14 @@ struct mmc_async_req *mmc_start_req(struct
>>> mmc_host *host,
>>> if (host->areq) {
>>> mmc_wait_for_req_done(host, host->areq->mrq);
>>> err = host->areq->err_check(host->card, host->areq);
>>> + /*
>>> + * Check BKOPS urgency for each R1 response
>>> + */
>>> + if (host->card && mmc_card_mmc(host->card) &&
>>> + ((mmc_resp_type(host->areq->mrq->cmd) == MMC_RSP_R1) ||
>>> + (mmc_resp_type(host->areq->mrq->cmd) == MMC_RSP_R1B))
>>> &&
>>> + (host->areq->mrq->cmd->resp[0] & R1_EXCEPTION_EVENT))
>>> + mmc_start_bkops(host->card, true);
>>> }
>>>
>>> if (!err && areq)
>>> @@ -489,6 +567,53 @@ 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 stop 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;
>>> +
>>> + BUG_ON(!card);
>>> + err = mmc_interrupt_hpi(card);
>>> +
>>> + /*
>>> + * if err is EINVAL, it's status that can't issue HPI.
>>> + * it should complete the BKOPS.
>>> + */
>>> + if (!err || (err == -EINVAL)) {
>>> + mmc_card_clr_doing_bkops(card);
>>> + err = 0;
>>> + }
>>> +
>>> + return err;
>>> +}
>>> +EXPORT_SYMBOL(mmc_stop_bkops);
>>> +
>>> +int mmc_read_bkops_status(struct mmc_card *card)
>>> +{
>>> + int err;
>>> + u8 ext_csd[512];
>>
>> 512 byte stack? Isn't it really a problem?
> How about this?
>
> +int mmc_read_bkops_status(struct mmc_card *card)
> +{
> + int err;
> + u8 *ext_csd;
> +
> + ext_csd = kmalloc(512, GFP_KERNEL);
> + if (!ext_csd) {
> + pr_err("%s: could not allocate a buffer to "
> + "receive the ext_csd.\n", mmc_hostname(card->host));
> + return -ENOMEM;
> + }
> +
> + mmc_claim_host(card->host);
> + err = mmc_send_ext_csd(card, ext_csd);
> + mmc_release_host(card->host);
> + if (err)
> + goto out;
> +
> + card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
> + card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXP_EVENTS_STATUS];
> +out:
> + kfree(ext_csd);
> + return err;
> +}
> +EXPORT_SYMBOL(mmc_read_bkops_status);
>
> Best Regards,
> Jaehoon Chung
>
>
>
>
I'm not sure it would be a good idea to allocate the buffer every time the
ext_csd is read since with the periodic BKOPs we might do it more often to
see if there is a need for BKOPs.
How about keeping the buffer in the card structure?
Thanks,
Maya
--
Sent by consultant of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
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