linux-kernel - Re: [PATCH 2/2]: Be stric clocksource/drivers/fttmr010ter on IRQs

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Date:   Mon, 30 Aug 2021 16:00:10 +0930
From:   "Andrew Jeffery" <andrew@...id.au>
To:     "Guenter Roeck" <linux@...ck-us.net>,
        Cédric Le Goater <clg@...d.org>,
        "Linus Walleij" <linus.walleij@...aro.org>
Cc:     "Daniel Lezcano" <daniel.lezcano@...aro.org>,
        "Thomas Gleixner" <tglx@...utronix.de>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "Joel Stanley" <joel@....id.au>
Subject: Re: [PATCH 2/2]: Be stric clocksource/drivers/fttmr010ter on IRQs



On Mon, 30 Aug 2021, at 14:28, Guenter Roeck wrote:
> On 8/29/21 9:16 PM, Andrew Jeffery wrote:
> [ ... ]
> >>
> >>> I don't have the manuals, so I can't say what the correct behavior is,
> >>> but at least there is some evidence that TIMER_INTR_STATE may not exist
> >>> on ast2400 and ast2500 SOCs.
> >>
> >> On Aspeed SoCs AST2400 and AST2500, the TMC[34] register is a
> >> "control register #2" whereas on the AST2600 it is an "interruptarch/arm/boot/dts/ast2600-facebook-netbmc-common.dtsi:#include
> >> status register" with bits [0-7] holding the timers status.
> >>
> >> I would say that the patch simply should handle the "is_aspeed" case.
> > 
> > Well, is_aspeed is set true in the driver for all of the 2400, 2500 and
> > 2600. 0x34 behaves the way this patch expects on the 2600. So I think
> > we need something less coarse than is_aspeed?
> > 
> 
> If I understand the code correctly, ast2400 and ast2500 execute
> fttmr010_timer_interrupt(), while ast2600 has its own interrupt handler.
> To make this work, it would probably be necessary to check for is_aspeed
> in fttmr010_timer_interrupt(), and only execute the new code if the flag
> is false. The existing flag in struct fttmr010 should be good enough
> for that.

Sounds good.

Andrew