linux-kernel - Re: [PATCH 2/7] clocksource: timer-npcm7xx: Enable timer 1 clock before use

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <YmpmMGsI2GLrvMg5@latitude>
Date:   Thu, 28 Apr 2022 12:02:24 +0200
From:   Jonathan Neuschäfer <j.neuschaefer@....net>
To:     Zev Weiss <zweiss@...inix.com>
Cc:     Jonathan Neuschäfer <j.neuschaefer@....net>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        "openbmc@...ts.ozlabs.org" <openbmc@...ts.ozlabs.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        "linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Patrick Venture <venture@...gle.com>,
        Michael Turquette <mturquette@...libre.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Avi Fishman <avifishman70@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Benjamin Fair <benjaminfair@...gle.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Tali Perry <tali.perry1@...il.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Guenter Roeck <linux@...ck-us.net>,
        Tomer Maimon <tmaimon77@...il.com>
Subject: Re: [PATCH 2/7] clocksource: timer-npcm7xx: Enable timer 1 clock
 before use

On Thu, Apr 28, 2022 at 09:11:58AM +0000, Zev Weiss wrote:
> On Fri, Apr 22, 2022 at 11:30:07AM PDT, Jonathan Neuschäfer wrote:
> >In the WPCM450 SoC, the clocks for each timer can be gated individually.
> >To prevent the timer 1 clock from being gated, enable it explicitly.
> >
> >Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@....net>
> >---
> > drivers/clocksource/timer-npcm7xx.c | 14 +++++++++++++-
> > 1 file changed, 13 insertions(+), 1 deletion(-)
> >
> >diff --git a/drivers/clocksource/timer-npcm7xx.c b/drivers/clocksource/timer-npcm7xx.c
> >index a00520cbb660a..974269b6b0c36 100644
> >--- a/drivers/clocksource/timer-npcm7xx.c
> >+++ b/drivers/clocksource/timer-npcm7xx.c
> >@@ -188,17 +188,29 @@ static void __init npcm7xx_clocksource_init(void)
> >
> > static int __init npcm7xx_timer_init(struct device_node *np)
> > {
> >+	struct clk *clk;
> > 	int ret;
> >
> > 	ret = timer_of_init(np, &npcm7xx_to);
> >-	if (ret)
> >+	if (ret) {
> >+		pr_warn("timer_of_init failed: %d\n", ret);
> 
> This seems like a somewhat opaque message to emit, especially given this
> file's lack of a pr_fmt() definition -- maybe add a %pOF so it's
> slightly easier to trace back to the device it stems from?

Now that I look at this code again, I think I should just drop the
pr_warn entirely, since I didn't mention it in the description, and it's
unrelated to enabling the clock.

> > 		return ret;
> >+	}
> >
> > 	/* Clock input is divided by PRESCALE + 1 before it is fed */
> > 	/* to the counter */
> > 	npcm7xx_to.of_clk.rate = npcm7xx_to.of_clk.rate /
> > 		(NPCM7XX_Tx_MIN_PRESCALE + 1);
> >
> >+	/* Enable the clock for timer1, if it exists */
> >+	clk = of_clk_get(np, 1);
> >+	if (clk) {
> >+		if (!IS_ERR(clk))
> >+			clk_prepare_enable(clk);
> >+		else
> >+			pr_warn("Failed to get clock for timer1: %pe", clk);
> 
> Likewise here (though to a slightly lesser extent).

I'll add %pOF here.


Thanks,
Jonathan

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)