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?
--
Kind regards,
Minchan Kim
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