linux-kernel - RE: [PATCH] i2c: aspeed: Fix the dummy irq expected print

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Date: Thu, 22 Feb 2024 01:10:39 +0000
From: Tommy Huang <tommy_huang@...eedtech.com>
To: Andi Shyti <andi.shyti@...nel.org>
CC: "brendan.higgins@...ux.dev" <brendan.higgins@...ux.dev>,
	"p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
	"linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
	"openbmc@...ts.ozlabs.org" <openbmc@...ts.ozlabs.org>,
	"benh@...nel.crashing.org" <benh@...nel.crashing.org>, "joel@....id.au"
	<joel@....id.au>, "andrew@...id.au" <andrew@...id.au>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "linux-aspeed@...ts.ozlabs.org"
	<linux-aspeed@...ts.ozlabs.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, BMC-SW <BMC-SW@...eedtech.com>
Subject: RE: [PATCH] i2c: aspeed: Fix the dummy irq expected print

Hi Andy,

	Thanks for your comment.

> -----Original Message-----
> From: Andi Shyti <andi.shyti@...nel.org>
> Sent: Thursday, February 22, 2024 5:15 AM
> To: Tommy Huang <tommy_huang@...eedtech.com>
> Cc: brendan.higgins@...ux.dev; p.zabel@...gutronix.de;
> linux-i2c@...r.kernel.org; openbmc@...ts.ozlabs.org;
> benh@...nel.crashing.org; joel@....id.au; andrew@...id.au;
> linux-arm-kernel@...ts.infradead.org; linux-aspeed@...ts.ozlabs.org;
> linux-kernel@...r.kernel.org; BMC-SW <BMC-SW@...eedtech.com>
> Subject: Re: [PATCH] i2c: aspeed: Fix the dummy irq expected print
> 
> Hi Tommy,
> 
> On Fri, Feb 16, 2024 at 08:04:55PM +0800, Tommy Huang wrote:
> > When the i2c error condition occurred and master state was not idle,
> > the master irq function will goto complete state without any other
> > interrupt handling. It would cause dummy irq expected print. Under
> > this condition, assign the irq_status into irq_handle.
> 
> I'm sorry, but I don't understand much from your log here.
> 
> Do you mean that irq_handled in aspeed_i2c_master_irq() is left with some
> states that is not supposed to have and then you end up printing here:
> 
> 	dev_err(bus->dev,
> 		"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
> 		irq_received, irq_handled);
> 
> Can you please explain better?
> 

Yes. If the platform met any irq error condition and the i2c wasn't stated under ASPEED_I2C_MASTER_INACTIVE.
Then the code flow would goto the end of aspeed_i2c_master_irq.

	ret = aspeed_i2c_is_irq_error(irq_status);
	if (ret) {
		...
		irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
		if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
			bus->cmd_err = ret;
			bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
			goto out_complete;
		}
	}

Some master interrupt states were not handled under this situation.
The fake irq not equaled message would be filled into whole of demsg.
It's most like below example.

..
aspeed-i2c-bus 1e78a780. i2c-bus: irq handled != irq. expected 0x00000030, but was 0x00000020
aspeed-i2c-bus 1e78a780. i2c-bus: irq handled != irq. expected 0x00000030, but was 0x00000020
aspeed-i2c-bus 1e78a780. i2c-bus: irq handled != irq. expected 0x00000030, but was 0x00000020
..

I thought the bus->cmd_err has been filled error reason and it would be returned to upper layer.
So, I didn't think the print should be existed.

> If that's the case, wouldn't it make more sense to check for
> bus->master_state != ASPEED_I2C_MASTER_INACTIVE) earlier?
> 

Did you suggest to add "bus->master_state != ASPEED_I2C_MASTER_INACTIVE" judgement before print the irq not equal print?

> And, still, If that's the case, I believe you might need the Fixes tag. It's true that
> you are not really failing, but you are not reporting a failure by mistake.
> 
> Thanks,
> Andi
> 
> > Signed-off-by: Tommy Huang <tommy_huang@...eedtech.com>
> > ---
> >  drivers/i2c/busses/i2c-aspeed.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/i2c/busses/i2c-aspeed.c
> > b/drivers/i2c/busses/i2c-aspeed.c index 5511fd46a65e..ce8c4846b7fa
> > 100644
> > --- a/drivers/i2c/busses/i2c-aspeed.c
> > +++ b/drivers/i2c/busses/i2c-aspeed.c
> > @@ -445,6 +445,7 @@ static u32 aspeed_i2c_master_irq(struct
> aspeed_i2c_bus *bus, u32 irq_status)
> >  			irq_status);
> >  		irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
> >  		if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
> > +			irq_handled = irq_status;
> >  			bus->cmd_err = ret;
> >  			bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
> >  			goto out_complete;
> > --
> > 2.25.1
> >