linux-kernel - Re: [PATCH v1 1/2] clocksource/drivers/exynos_mct_v2: introduce Exynos MCT version 2 driver for next Exynos SoC

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Message-ID: <117dfec8-e417-642b-7647-9d17592826ad@canonical.com>
Date:   Wed, 27 Oct 2021 10:38:09 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Youngmin Nam <youngmin.nam@...sung.com>
Cc:     daniel.lezcano@...aro.org, tglx@...utronix.de,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, pullip.cho@...sung.com,
        hoony.yu@...sung.com, hajun.sung@...sung.com,
        myung-su.cha@...sung.com
Subject: Re: [PATCH v1 1/2] clocksource/drivers/exynos_mct_v2: introduce
 Exynos MCT version 2 driver for next Exynos SoC

On 21/10/2021 08:18, Youngmin Nam wrote:
> Exynos MCT version 2 is composed of 1 FRC and 12 comparators.
> The 12 comparators can produces interrupts independently,
> so they can be used as local timer of each CPU.
> 

...

> +
> +static void exynos_mct_comp_start(struct mct_clock_event_device *mevt,
> +				  bool periodic, unsigned long cycles)
> +{
> +	unsigned int index = mevt->comp_index;
> +	unsigned int comp_enable;
> +	unsigned int loop_cnt = 0;
> +
> +	comp_enable = readl_relaxed(reg_base + EXYNOS_MCT_COMP_ENABLE(index));
> +	if (comp_enable == MCT_COMP_ENABLE)
> +		exynos_mct_comp_stop(mevt);
> +
> +	if (periodic)
> +		writel_relaxed(MCT_COMP_CIRCULAR_MODE, reg_base + EXYNOS_MCT_COMP_MODE(index));
> +
> +	writel_relaxed(cycles, reg_base + EXYNOS_MCT_COMP_PERIOD(index));

This is unsigned long, so 64-bit on your platform. Use writeq_relaxed or
handle it somehow.


Best regards,
Krzysztof