RE: [PATCH v1] ufs: introduce UFSHCD_QUIRK_USE_OF_HCE quirk

[Kiwoong Kim <kwmad.kim@samsung.com>]

> On 2016-11-07 23:57, Kiwoong Kim wrote:
> > Some host controller might not initialize itself by setting "Host
> > Controller Enable" to 1.
> 
> > They should do this to reset UIC.
> 
> I am not sure if i understood this statment. can you give more details?

UFSHCI spec says as follows:
- When HCE is ‘0’ and software writes ‘1’, the host 
controller hardware shall execute the step 2 described in section 7.1.1
of this standard, including reset of the host UTP and UIC layers.

I found that a specific controller didn't execute reset of UIC layers
Properly for an internal problem.
At that time, DME reset and DME enable could make UIC be reset properly
instead of using "Host Controller Enable".

> 
> > In such cases, 'DME reset' and 'DME enable' are required for normal
> > subsequent operations.
> 
> This means HCE implementation is broken, you should name the quirk as
> UFSHCD_QUIRK_BROKEN_HCE .

Okay.

> 
> >
> > Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> > ---
> >  drivers/scsi/ufs/ufshcd.c | 44
> > +++++++++++++++++++++++++++++++++++++++++++-
> >  drivers/scsi/ufs/ufshcd.h |  1 +
> >  2 files changed, 44 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> > index 24d6ea7..c904854 100644
> > --- a/drivers/scsi/ufs/ufshcd.c
> > +++ b/drivers/scsi/ufs/ufshcd.c
> > @@ -2496,6 +2496,37 @@ static inline void
> > ufshcd_add_delay_before_dme_cmd(struct ufs_hba *hba)
> >  	usleep_range(min_sleep_time_us, min_sleep_time_us + 50);  }
> >
> > +static int ufshcd_dme_reset(struct ufs_hba *hba) {
> > +	struct uic_command uic_cmd = {0};
> > +	int ret;
> > +
> > +	uic_cmd.command = UIC_CMD_DME_RESET;
> > +	uic_cmd.argument1 = 0x1;
> > +
> > +	ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> > +	if (ret)
> > +		dev_err(hba->dev,
> > +			"dme-reset: error code %d\n", ret);
> 
> This error message doesn't say which DME command failed, do you want to
> add that?

I think that the string "dme-reset" is useful when clarifying some problems.
But if you don't agree merging it to mainline, I'll remove it in next
version.

> 
> > +
> > +	return ret;
> > +}
> > +
> > +static int ufshcd_dme_enable(struct ufs_hba *hba) {
> > +	struct uic_command uic_cmd = {0};
> > +	int ret;
> > +
> > +	uic_cmd.command = UIC_CMD_DME_ENABLE;
> > +
> > +	ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
> > +	if (ret)
> > +		dev_err(hba->dev,
> > +			"dme-enable: error code %d\n", ret);
> 
> This error message doesn't say which DME command failed, do you want to
> add that?

Same with above.

> 
> > +
> > +	return ret;
> > +}
> > +
> >  /**
> >   * ufshcd_dme_set_attr - UIC command for DME_SET, DME_PEER_SET
> >   * @hba: per adapter instance
> > @@ -3101,6 +3132,7 @@ static inline void ufshcd_hba_stop(struct
> > ufs_hba *hba, bool can_sleep)  static int ufshcd_hba_enable(struct
> > ufs_hba *hba)  {
> >  	int retry;
> > +	int ret = 0;
> >
> >  	/*
> >  	 * msleep of 1 and 5 used in this function might result in
> > msleep(20), @@ -3117,6 +3149,9 @@ static int ufshcd_hba_enable(struct
> > ufs_hba *hba)
> >
> >  	ufshcd_vops_hce_enable_notify(hba, PRE_CHANGE);
> >
> > +	if (hba->quirks & UFSHCD_QUIRK_USE_OF_HCE)
> > +		goto use_dme;
> > +
> >  	/* start controller initialization sequence */
> >  	ufshcd_hba_start(hba);
> >
> > @@ -3145,12 +3180,19 @@ static int ufshcd_hba_enable(struct ufs_hba
> > *hba)
> >  		msleep(5);
> >  	}
> >
> > +use_dme:
> >  	/* enable UIC related interrupts */
> >  	ufshcd_enable_intr(hba, UFSHCD_UIC_MASK);
> >
> > +	if (hba->quirks & UFSHCD_QUIRK_USE_OF_HCE) {
> > +		ret = ufshcd_dme_reset(hba);
> > +		if (!ret)
> > +			ret = ufshcd_dme_enable(hba);
> > +	}
> > +
> >  	ufshcd_vops_hce_enable_notify(hba, POST_CHANGE);
> >
> > -	return 0;
> > +	return ret;
> >  }
> >
> >  static int ufshcd_disable_tx_lcc(struct ufs_hba *hba, bool peer) diff
> > --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index
> > c4abd76..6a96f24 100644
> > --- a/drivers/scsi/ufs/ufshcd.h
> > +++ b/drivers/scsi/ufs/ufshcd.h
> > @@ -496,6 +496,7 @@ struct ufs_hba {
> >  	#define UFSHCD_QUIRK_GET_VS_RESULT			UFS_BIT(6)
> >  	#define UFSHCD_QUIRK_BROKEN_DWORD_UTRD                  UFS_BIT(7)
> >  	#define UFSHCD_QUIRK_BROKEN_REQ_LIST_CLR                UFS_BIT(8)
> > +	#define UFSHCD_QUIRK_USE_OF_HCE				UFS_BIT(9)
> >
> >
> >  	unsigned int quirks;	/* Deviations from standard UFSHCI spec.
> */
> 
> --
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