Re: [PATCH v4] mmc: support BKOPS feature for eMMC

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Chris,

On 01/03/2012 09:47 AM, Chris Ball wrote:

> Hi,
> 
> On Sun, Jan 01 2012, Jaehoon Chung wrote:
>> Enable eMMC background operations (BKOPS) feature.
>>
>> If URGENT_BKOPS is set after a response, note that BKOPS
>> are required. After all I/O requests are finished, run
>> BKOPS if required. Should read/write operations be requested
>> during BKOPS, first issue HPI to interrupt the ongoing BKOPS
>> and then service the request.
>>
>> If you want to enable this feature, set MMC_CAP2_BKOPS.
>>
>> 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?)
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
>> ---
>> 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/card/block.c   |   10 ++++
>>  drivers/mmc/card/queue.c   |    3 +
>>  drivers/mmc/core/core.c    |  104 ++++++++++++++++++++++++++++++++++++++++++++
>>  drivers/mmc/core/mmc.c     |    8 +++
>>  drivers/mmc/core/mmc_ops.c |   12 +++++-
>>  include/linux/mmc/card.h   |   14 ++++++
>>  include/linux/mmc/core.h   |    4 ++
>>  include/linux/mmc/host.h   |    1 +
>>  include/linux/mmc/mmc.h    |   19 ++++++++
>>  9 files changed, 174 insertions(+), 1 deletions(-)
>>
> 
> This doesn't apply against mmc-next.  Please rebase and resend?

Sure, i will rebase and resend the patch with your comments
Thanks,
Jaehoon Chung

> 
>> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
>> index 0cad48a..9c214e4 100644
>> --- a/drivers/mmc/card/block.c
>> +++ b/drivers/mmc/card/block.c
>> @@ -1273,6 +1273,16 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>>  		type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
>>  		mmc_queue_bounce_post(mq_rq);
>>  
>> +		/*
>> +		 * Check BKOPS urgency from each R1 response
>> +		 */
>> +		if (mmc_card_mmc(card) && ((brq->cmd.flags == MMC_RSP_R1B) ||
>> +			 (brq->cmd.flags == MMC_RSP_R1)) &&
>> +			(brq->cmd.resp[0] & R1_EXCEPTION_EVENT)) {
> 
> This is hard to follow.  I suggest:
> 
> 		if (mmc_card_mmc(card) &&
> 		    (brq->cmd.flags == MMC_RSP_R1B ||
> 		     brq->cmd.flags == MMC_RSP_R1) &&
> 		    (brq->cmd.resp[0] & R1_EXCEPTION_EVENT) {
> 
>> +			if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS))
>> +				mmc_card_set_need_bkops(card);
>> +		}
>> +
>>  		switch (status) {
>>  		case MMC_BLK_SUCCESS:
>>  		case MMC_BLK_PARTIAL:
>> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
>> index 2517547..fd11a31 100644
>> --- a/drivers/mmc/card/queue.c
>> +++ b/drivers/mmc/card/queue.c
>> @@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
>>  		spin_unlock_irq(q->queue_lock);
>>  
>>  		if (req || mq->mqrq_prev->req) {
>> +			if (mmc_card_doing_bkops(mq->card))
>> +				mmc_interrupt_bkops(mq->card);
>>  			set_current_state(TASK_RUNNING);
>>  			mq->issue_fn(mq, req);
>>  		} else {
>> @@ -73,6 +75,7 @@ static int mmc_queue_thread(void *d)
>>  				set_current_state(TASK_RUNNING);
>>  				break;
>>  			}
>> +			mmc_start_bkops(mq->card);
>>  			up(&mq->thread_sem);
>>  			schedule();
>>  			down(&mq->thread_sem);
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index a2aa860..627697a 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -238,6 +238,51 @@ 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
>> + *
>> + *	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)
>> +{
>> +	int err;
>> +	unsigned long flags;
>> +
>> +	BUG_ON(!card);
>> +	if ((!card->ext_csd.bkops_en) ||
>> +			!(card->host->caps2 & MMC_CAP2_BKOPS))
> 
>         if (!card->ext_csd.bkops_en || !(card->host->caps2 & MMC_CAP2_BKOPS))
> 
>> +		return;
>> +
>> +	/*
>> +	 * If card is already doing bkops or need for
>> +	 * bkops flag is not set, then do nothing just
>> +	 * return
>> +	 */
>> +	if (mmc_card_doing_bkops(card)
>> +			|| !mmc_card_need_bkops(card))
> 
>         if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
> 
>> +		return;
>> +
>> +	mmc_claim_host(card->host);
>> +	err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> +			EXT_CSD_BKOPS_START, 1, 0);
>> +	if (err) {
>> +		pr_warning("error %d starting bkops\n", err);
> 
> Add an mmc_hostname so that users know this is coming from mmc.
> 
>> +		mmc_card_clr_need_bkops(card);
>> +		goto out;
>> +	}
>> +	spin_lock_irqsave(&card->host->lock, flags);
>> +	mmc_card_clr_need_bkops(card);
>> +	if (card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
>> +		mmc_card_set_doing_bkops(card);
>> +	spin_unlock_irqrestore(&card->host->lock, flags);
>> +out:
>> +	mmc_release_host(card->host);
>> +}
>> +EXPORT_SYMBOL(mmc_start_bkops);
>> +
>>  static void mmc_wait_done(struct mmc_request *mrq)
>>  {
>>  	complete(&mrq->completion);
>> @@ -472,6 +517,65 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
>>  EXPORT_SYMBOL(mmc_wait_for_cmd);
>>  
>>  /**
>> + *	mmc_interrupt_bkops - interrupt 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_interrupt_bkops(struct mmc_card *card)
>> +{
>> +	int err = 0;
>> +	unsigned long flags;
>> +
>> +	BUG_ON(!card);
>> +
>> +	err = mmc_interrupt_hpi(card);
>> +
>> +	spin_lock_irqsave(&card->host->lock, flags);
>> +	mmc_card_clr_doing_bkops(card);
>> +	spin_unlock_irqrestore(&card->host->lock, flags);
>> +
>> +	return err;
>> +}
>> +EXPORT_SYMBOL(mmc_interrupt_bkops);
>> +
>> +int mmc_read_bkops_status(struct mmc_card *card)
>> +{
>> +	int err;
>> +	u8 ext_csd[512];
>> +
>> +	err = mmc_send_ext_csd(card, ext_csd);
>> +	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];
>> +out:
>> +	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);
>> +
>> +	/* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
>> +	if (card->ext_csd.rev == 5)
>> +		return 1;
>> +
>> +	if (err)
>> +		return 0;
> 
> The placement of the csd.rev inbetween setting and testing "err" is odd.
> I think it should go before mmc_read_bkops_status() if it's unrelated.
> 
>> +
>> +	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
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> index f0a9f1f..94456b1 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -459,6 +459,14 @@ 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];
>> +		}
>> +
>>  		/* 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 4d41fa9..040f144 100644
>> --- a/drivers/mmc/core/mmc_ops.c
>> +++ b/drivers/mmc/core/mmc_ops.c
>> @@ -392,13 +392,23 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
>>  		  (index << 16) |
>>  		  (value << 8) |
>>  		  set;
>> -	cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
>> +	cmd.flags = MMC_CMD_AC;
>> +	if (index == EXT_CSD_BKOPS_START &&
>> +		card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
>> +		cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
> 
>         if (index == EXT_CSD_BKOPS_START &&
>             card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
>                 cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
> 
>> +	else
>> +		cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;
>> +
>>  	cmd.cmd_timeout_ms = timeout_ms;
>>  
>>  	err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
>>  	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 9478a6b..b9e255f 100644
>> --- a/include/linux/mmc/card.h
>> +++ b/include/linux/mmc/card.h
>> @@ -71,8 +71,11 @@ 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 */
>>  	unsigned int		boot_ro_lock;		/* ro lock support */
>>  	bool			boot_ro_lockable;
>> +	u8			raw_exception_status;	/* 53 */
>>  	u8			raw_partition_support;	/* 160 */
>>  	u8			raw_erased_mem_count;	/* 181 */
>>  	u8			raw_ext_csd_structure;	/* 194 */
>> @@ -86,6 +89,7 @@ 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;
>> @@ -216,6 +220,9 @@ struct mmc_card {
>>  #define MMC_STATE_ULTRAHIGHSPEED (1<<5)		/* card is in ultra high speed mode */
>>  #define MMC_CARD_SDXC		(1<<6)		/* card is SDXC */
>>  #define MMC_CARD_REMOVED	(1<<7)		/* card has been removed */
>> +#define MMC_STATE_NEED_BKOPS	(1<<8)		/* card need to do BKOPS */
>> +#define MMC_STATE_DOING_BKOPS	(1<<9)		/* card is doing 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 */
>> @@ -380,6 +387,8 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>>  #define mmc_sd_card_uhs(c)	((c)->state & MMC_STATE_ULTRAHIGHSPEED)
>>  #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_need_bkops(c)	((c)->state & MMC_STATE_NEED_BKOPS)
>> +#define mmc_card_doing_bkops(c)	((c)->state & MMC_STATE_DOING_BKOPS)
>>  
>>  #define mmc_card_set_present(c)	((c)->state |= MMC_STATE_PRESENT)
>>  #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
>> @@ -390,6 +399,11 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>>  #define mmc_sd_card_set_uhs(c) ((c)->state |= MMC_STATE_ULTRAHIGHSPEED)
>>  #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_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_clr_need_bkops(c)	((c)->state &= ~MMC_STATE_NEED_BKOPS)
>> +#define mmc_card_clr_doing_bkops(c)	((c)->state &= ~MMC_STATE_DOING_BKOPS)
>>  
>>  /*
>>   * Quirk add/remove for MMC products.
>> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
>> index 87a976c..45357c7 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_interrupt_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 +166,7 @@ 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_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 742f0e1..02ef040 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -247,6 +247,7 @@ struct mmc_host {
>>  #define MMC_CAP2_CACHE_CTRL	(1 << 1)	/* Allow cache control */
>>  #define MMC_CAP2_POWEROFF_NOTIFY (1 << 2)	/* Notify poweroff supported */
>>  #define MMC_CAP2_NO_MULTI_READ	(1 << 3)	/* Multiblock reads don't work */
>> +#define MMC_CAP2_BKOPS		(1 << 4)	/* BKOPS supported */
>>  
>>  	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 665548e..8cc1a03 100644
>> --- a/include/linux/mmc/mmc.h
>> +++ b/include/linux/mmc/mmc.h
>> @@ -138,6 +138,7 @@ 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
>> @@ -273,11 +274,14 @@ 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_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 */
>> @@ -311,9 +315,11 @@ 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_BKOPS_SUPPORT		502	/* RO */
>>  #define EXT_CSD_HPI_FEATURES		503	/* RO */
>>  
>>  /*
>> @@ -379,4 +385,17 @@ 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
>> +
>> +/*
>> + * 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 */
> 
> Thanks,
> 
> - Chris.