From: Vincent Whitchurch <vincent.whitchurch@axis.com> To: <krzk@kernel.org>, <tglx@linutronix.de>, <daniel.lezcano@linaro.org> Cc: <kernel@axis.com>, Vincent Whitchurch <vincent.whitchurch@axis.com>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-samsung-soc@vger.kernel.org>, <alim.akhtar@samsung.com>, <devicetree@vger.kernel.org>, <robh+dt@kernel.org> Subject: [PATCH v3 2/4] clocksource/drivers/exynos_mct: Support frc-shared property Date: Thu, 7 Apr 2022 09:44:30 +0200 [thread overview] Message-ID: <20220407074432.424578-3-vincent.whitchurch@axis.com> (raw) In-Reply-To: <20220407074432.424578-1-vincent.whitchurch@axis.com> When the FRC is shared with another main processor, the other processor is assumed to have started it and this processor should not write to the global registers. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> --- Notes: v3: - Split FRC sharing handling from local timer indices handling - Remove addition of global variable. drivers/clocksource/exynos_mct.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index f29c812b70c9..12023831dedf 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -233,9 +233,16 @@ static cycles_t exynos4_read_current_timer(void) } #endif -static int __init exynos4_clocksource_init(void) +static int __init exynos4_clocksource_init(bool frc_shared) { - exynos4_mct_frc_start(); + /* + * When the frc is shared, the main processer should have already + * turned it on and we shouldn't be writing to TCON. + */ + if (frc_shared) + mct_frc.resume = NULL; + else + exynos4_mct_frc_start(); #if defined(CONFIG_ARM) exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer; @@ -605,6 +612,7 @@ static int __init exynos4_timer_interrupts(struct device_node *np, static int __init mct_init_dt(struct device_node *np, unsigned int int_type) { + bool frc_shared = of_property_read_bool(np, "samsung,frc-shared"); int ret; ret = exynos4_timer_resources(np); @@ -615,10 +623,17 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type) if (ret) return ret; - ret = exynos4_clocksource_init(); + ret = exynos4_clocksource_init(frc_shared); if (ret) return ret; + /* + * When the FRC is shared with a main processor, this secondary + * processor cannot use the global comparator. + */ + if (frc_shared) + return ret; + return exynos4_clockevent_init(); } -- 2.34.1
WARNING: multiple messages have this Message-ID (diff)
From: Vincent Whitchurch <vincent.whitchurch@axis.com> To: <krzk@kernel.org>, <tglx@linutronix.de>, <daniel.lezcano@linaro.org> Cc: <kernel@axis.com>, Vincent Whitchurch <vincent.whitchurch@axis.com>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <linux-samsung-soc@vger.kernel.org>, <alim.akhtar@samsung.com>, <devicetree@vger.kernel.org>, <robh+dt@kernel.org> Subject: [PATCH v3 2/4] clocksource/drivers/exynos_mct: Support frc-shared property Date: Thu, 7 Apr 2022 09:44:30 +0200 [thread overview] Message-ID: <20220407074432.424578-3-vincent.whitchurch@axis.com> (raw) In-Reply-To: <20220407074432.424578-1-vincent.whitchurch@axis.com> When the FRC is shared with another main processor, the other processor is assumed to have started it and this processor should not write to the global registers. Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> --- Notes: v3: - Split FRC sharing handling from local timer indices handling - Remove addition of global variable. drivers/clocksource/exynos_mct.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index f29c812b70c9..12023831dedf 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -233,9 +233,16 @@ static cycles_t exynos4_read_current_timer(void) } #endif -static int __init exynos4_clocksource_init(void) +static int __init exynos4_clocksource_init(bool frc_shared) { - exynos4_mct_frc_start(); + /* + * When the frc is shared, the main processer should have already + * turned it on and we shouldn't be writing to TCON. + */ + if (frc_shared) + mct_frc.resume = NULL; + else + exynos4_mct_frc_start(); #if defined(CONFIG_ARM) exynos4_delay_timer.read_current_timer = &exynos4_read_current_timer; @@ -605,6 +612,7 @@ static int __init exynos4_timer_interrupts(struct device_node *np, static int __init mct_init_dt(struct device_node *np, unsigned int int_type) { + bool frc_shared = of_property_read_bool(np, "samsung,frc-shared"); int ret; ret = exynos4_timer_resources(np); @@ -615,10 +623,17 @@ static int __init mct_init_dt(struct device_node *np, unsigned int int_type) if (ret) return ret; - ret = exynos4_clocksource_init(); + ret = exynos4_clocksource_init(frc_shared); if (ret) return ret; + /* + * When the FRC is shared with a main processor, this secondary + * processor cannot use the global comparator. + */ + if (frc_shared) + return ret; + return exynos4_clockevent_init(); } -- 2.34.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-04-07 7:44 UTC|newest] Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-07 7:44 [PATCH v3 0/4] clocksource: Add MCT support for ARTPEC-8 Vincent Whitchurch 2022-04-07 7:44 ` Vincent Whitchurch 2022-04-07 7:44 ` [PATCH v3 1/4] dt-bindings: timer: exynos4210-mct: Add ARTPEC-8 MCT support Vincent Whitchurch 2022-04-07 7:44 ` Vincent Whitchurch 2022-04-07 15:04 ` Rob Herring 2022-04-07 15:04 ` Rob Herring 2022-04-08 6:58 ` Vincent Whitchurch 2022-04-08 6:58 ` Vincent Whitchurch 2022-04-08 7:16 ` Krzysztof Kozlowski 2022-04-08 7:16 ` Krzysztof Kozlowski 2022-04-07 7:44 ` Vincent Whitchurch [this message] 2022-04-07 7:44 ` [PATCH v3 2/4] clocksource/drivers/exynos_mct: Support frc-shared property Vincent Whitchurch 2022-04-08 7:17 ` Krzysztof Kozlowski 2022-04-08 7:17 ` Krzysztof Kozlowski 2022-04-07 7:44 ` [PATCH v3 3/4] clocksource/drivers/exynos_mct: Support local-timers property Vincent Whitchurch 2022-04-07 7:44 ` Vincent Whitchurch 2022-04-08 8:02 ` Krzysztof Kozlowski 2022-04-08 8:02 ` Krzysztof Kozlowski 2022-04-07 7:44 ` [PATCH v3 4/4] clocksource/drivers/exynos_mct: Enable building on ARTPEC Vincent Whitchurch 2022-04-07 7:44 ` Vincent Whitchurch
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