linux-kernel - RE: [RFC PATCH v1] ufs: poll HCS.UCRDY before issuing a UIC command

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Date:   Thu, 11 May 2023 08:35:18 +0900
From:   "Kiwoong Kim" <kwmad.kim@...sung.com>
To:     "'Bao D. Nguyen'" <quic_nguyenb@...cinc.com>,
        <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <alim.akhtar@...sung.com>, <avri.altman@....com>,
        <jejb@...ux.ibm.com>, <martin.petersen@...cle.com>,
        <beanhuo@...ron.com>, <adrian.hunter@...el.com>,
        <sc.suh@...sung.com>, <hy50.seo@...sung.com>,
        <sh425.lee@...sung.com>, <kwangwon.min@...sung.com>
Subject: RE: [RFC PATCH v1] ufs: poll HCS.UCRDY before issuing a UIC command

> On 5/9/2023 1:24 AM, Kiwoong Kim wrote:
> > With auto hibern8 enabled, UIC could be working for a while to process
> > a hibern8 operation and HCI reports UIC not ready for a short term
> > through HCS.UCRDY.
> > And UFS driver can't recognize the operation.
> > UFSHCI spec specifies UCRDY like this:
> > whether the host controller is ready to process UIC COMMAND
> >
> > The 'ready' could be seen as many different meanings. If the meaning
> > includes not processing any request from HCI, processing a hibern8
> > operation can be 'not ready'. In this situation, the driver needs to
> > wait until the operations is completed.
> >
> > Signed-off-by: Kiwoong Kim <kwmad.kim@...sung.com>
> > ---
> >   drivers/ufs/core/ufshcd.c | 13 ++++++++++++-
> >   1 file changed, 12 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> > index 96ce6af..fc79539 100644
> > --- a/drivers/ufs/core/ufshcd.c
> > +++ b/drivers/ufs/core/ufshcd.c
> > @@ -2368,7 +2368,18 @@ static inline int ufshcd_hba_capabilities(struct
> ufs_hba *hba)
> >    */
> >   static inline bool ufshcd_ready_for_uic_cmd(struct ufs_hba *hba)
> >   {
> > -	return ufshcd_readl(hba, REG_CONTROLLER_STATUS) & UIC_COMMAND_READY;
> > +	ktime_t timeout = ktime_add_ms(ktime_get(), UIC_CMD_TIMEOUT);
> > +	u32 val = 0;
> > +
> > +	do {
> > +		val = ufshcd_readl(hba, REG_CONTROLLER_STATUS) &
> > +			UIC_COMMAND_READY;
> > +		if (val)
> > +			break;
> > +		usleep_range(500, 1000);
> Hi Kiwoong,
> It looks like you are sleeping while holding the spin_lock_irqsave(hba-
> >host->host_lock, flags) in ufshcd_send_uic_cmd()?

Right. Let me fix it.

Thanks.
Kiwoong Kim

> 
> 
> > +	} while (ktime_before(ktime_get(), timeout));
> > +
> > +	return val ? true : false;
> >   }
> >
> >   /**