linux-kernel - Re: [PATCH 2/3] i2c: qcom-geni: Propagate GENI_ABORT_DONE to geni_i2c_abort

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Date:   Tue, 19 Jul 2022 15:57:38 -0500
From:   Andrew Halaney <ahalaney@...hat.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Vinod Koul <vkoul@...nel.org>, Wolfram Sang <wsa@...nel.org>,
        linux-arm-msm@...r.kernel.org, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] i2c: qcom-geni: Propagate GENI_ABORT_DONE to
 geni_i2c_abort_xfer()

On Tue, Jul 19, 2022 at 03:50:54PM -0500, Andrew Halaney wrote:
> On Sat, Jul 16, 2022 at 08:50:26PM -0700, Bjorn Andersson wrote:
> > Waiting for M_CMD_ABORT_EN in geni_i2c_abort_xfer() races with the
> > interrupt handler which will read and clear the abort bit, the result is
> > that every abort attempt takes 1 second and is followed by a message
> > about the abort having times out.
> > 
> > Introduce a new state variable to carry the abort_done state from the
> > interrupt handler back to geni_i2c_abort_xfer().
> > 
> > Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> > ---
> >  drivers/i2c/busses/i2c-qcom-geni.c | 16 +++++++++++-----
> >  1 file changed, 11 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
> > index 3bec7c782824..e212e7ae7ad2 100644
> > --- a/drivers/i2c/busses/i2c-qcom-geni.c
> > +++ b/drivers/i2c/busses/i2c-qcom-geni.c
> > @@ -97,6 +97,7 @@ struct geni_i2c_dev {
> >  	struct dma_chan *tx_c;
> >  	struct dma_chan *rx_c;
> >  	bool gpi_mode;
> > +	bool abort_done;
> >  };
> >  
> >  struct geni_i2c_err_log {
> > @@ -203,9 +204,14 @@ static void geni_i2c_err(struct geni_i2c_dev *gi2c, int err)
> >  		dev_dbg(gi2c->se.dev, "len:%d, slv-addr:0x%x, RD/WR:%d\n",
> >  			gi2c->cur->len, gi2c->cur->addr, gi2c->cur->flags);
> >  
> > -	if (err != NACK && err != GENI_ABORT_DONE) {
> > +	switch (err) {
> > +	case GENI_ABORT_DONE:
> > +		gi2c->abort_done = true;
> > +		break;
> > +	default:
> >  		dev_err(gi2c->se.dev, "%s\n", gi2c_log[err].msg);
> >  		geni_i2c_err_misc(gi2c);
> > +		break;
> >  	}
> >  }
> >  
> 
> If I'm reading this right this changes the behavior on a NACK error now,
> right? Was that intentional?
> 
> Otherwise looks good to me.
> 

Hmmm (I should really review the whole series before hitting send :P ),
it seems you cleaned the NACK stuff up in the next patch in the series.

I guess one more thing, does this patch deserve a Fixes: tag? If so
might be nice to make NACK not so loud in this patch in case it gets
backported without the next patch.

Thanks,
Andrew

> > @@ -311,21 +317,21 @@ static irqreturn_t geni_i2c_irq(int irq, void *dev)
> >  
> >  static void geni_i2c_abort_xfer(struct geni_i2c_dev *gi2c)
> >  {
> > -	u32 val;
> >  	unsigned long time_left = ABORT_TIMEOUT;
> >  	unsigned long flags;
> >  
> >  	spin_lock_irqsave(&gi2c->lock, flags);
> >  	geni_i2c_err(gi2c, GENI_TIMEOUT);
> >  	gi2c->cur = NULL;
> > +	gi2c->abort_done = false;
> >  	geni_se_abort_m_cmd(&gi2c->se);
> >  	spin_unlock_irqrestore(&gi2c->lock, flags);
> > +
> >  	do {
> >  		time_left = wait_for_completion_timeout(&gi2c->done, time_left);
> > -		val = readl_relaxed(gi2c->se.base + SE_GENI_M_IRQ_STATUS);
> > -	} while (!(val & M_CMD_ABORT_EN) && time_left);
> > +	} while (!gi2c->abort_done && time_left);
> >  
> > -	if (!(val & M_CMD_ABORT_EN))
> > +	if (!time_left)
> >  		dev_err(gi2c->se.dev, "Timeout abort_m_cmd\n");
> >  }
> >  
> > -- 
> > 2.35.1
> >