From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> To: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@suse.de>, Ashok Raj <ashok.raj@intel.com>, Joerg Roedel <joro@8bytes.org>, Andi Kleen <andi.kleen@intel.com>, Peter Zijlstra <peterz@infradead.org>, Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>, Stephane Eranian <eranian@google.com>, "Ravi V. Shankar" <ravi.v.shankar@intel.com>, Randy Dunlap <rdunlap@infradead.org>, x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Ricardo Neri <ricardo.neri@intel.com>, "H. Peter Anvin" <hpa@zytor.com>, Tony Luck <tony.luck@intel.com>, Philippe Ombredanne <pombredanne@nexb.com>, Kate Stewart <kstewart@linuxfoundation.org>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Subject: Re: [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Date: Tue, 18 Jun 2019 15:48:35 -0700 [thread overview] Message-ID: <20190618224835.GF30488@ranerica-svr.sc.intel.com> (raw) In-Reply-To: <alpine.DEB.2.21.1906142010230.1760@nanos.tec.linutronix.de> On Fri, Jun 14, 2019 at 08:17:14PM +0200, Thomas Gleixner wrote: > On Thu, 23 May 2019, Ricardo Neri wrote: > > +/** > > + * hpet_set_comparator() - Helper function for setting comparator register > > + * @num: The timer ID > > + * @cmp: The value to be written to the comparator/accumulator > > + * @period: The value to be written to the period (0 = oneshot mode) > > + * > > + * Helper function for updating comparator, accumulator and period values. > > + * > > + * In periodic mode, HPET needs HPET_TN_SETVAL to be set before writing > > + * to the Tn_CMP to update the accumulator. Then, HPET needs a second > > + * write (with HPET_TN_SETVAL cleared) to Tn_CMP to set the period. > > + * The HPET_TN_SETVAL bit is automatically cleared after the first write. > > + * > > + * For one-shot mode, HPET_TN_SETVAL does not need to be set. > > + * > > + * See the following documents: > > + * - Intel IA-PC HPET (High Precision Event Timers) Specification > > + * - AMD-8111 HyperTransport I/O Hub Data Sheet, Publication # 24674 > > + */ > > +void hpet_set_comparator(int num, unsigned int cmp, unsigned int period) > > +{ > > + if (period) { > > + unsigned int v = hpet_readl(HPET_Tn_CFG(num)); > > + > > + hpet_writel(v | HPET_TN_SETVAL, HPET_Tn_CFG(num)); > > + } > > + > > + hpet_writel(cmp, HPET_Tn_CMP(num)); > > + > > + if (!period) > > + return; > > TBH, I hate this conditional handling. What's wrong with two functions? There is probably nothing wrong with two functions. I can split it into hpet_set_comparator_periodic() and hpet_set_comparator(). Perhaps the latter is not needed as it would be a one-line function; you have suggested earlier to avoid such small functions. > > > + > > + /* > > + * This delay is seldom used: never in one-shot mode and in periodic > > + * only when reprogramming the timer. > > + */ > > + udelay(1); > > + hpet_writel(period, HPET_Tn_CMP(num)); > > +} > > +EXPORT_SYMBOL_GPL(hpet_set_comparator); > > Why is this exported? Which module user needs this? It is not used anywhere else. I will remove this export. Thanks and BR, Ricardo
WARNING: multiple messages have this Message-ID (diff)
From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> To: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org>, "Ravi V. Shankar" <ravi.v.shankar@intel.com>, x86@kernel.org, Ashok Raj <ashok.raj@intel.com>, Peter Zijlstra <peterz@infradead.org>, Philippe Ombredanne <pombredanne@nexb.com>, Randy Dunlap <rdunlap@infradead.org>, linux-kernel@vger.kernel.org, Stephane Eranian <eranian@google.com>, Ricardo Neri <ricardo.neri@intel.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, iommu@lists.linux-foundation.org, Tony Luck <tony.luck@intel.com>, "H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <andi.kleen@intel.com>, Borislav Petkov <bp@suse.de>, Ingo Molnar <mingo@kernel.org> Subject: Re: [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Date: Tue, 18 Jun 2019 15:48:35 -0700 [thread overview] Message-ID: <20190618224835.GF30488@ranerica-svr.sc.intel.com> (raw) In-Reply-To: <alpine.DEB.2.21.1906142010230.1760@nanos.tec.linutronix.de> On Fri, Jun 14, 2019 at 08:17:14PM +0200, Thomas Gleixner wrote: > On Thu, 23 May 2019, Ricardo Neri wrote: > > +/** > > + * hpet_set_comparator() - Helper function for setting comparator register > > + * @num: The timer ID > > + * @cmp: The value to be written to the comparator/accumulator > > + * @period: The value to be written to the period (0 = oneshot mode) > > + * > > + * Helper function for updating comparator, accumulator and period values. > > + * > > + * In periodic mode, HPET needs HPET_TN_SETVAL to be set before writing > > + * to the Tn_CMP to update the accumulator. Then, HPET needs a second > > + * write (with HPET_TN_SETVAL cleared) to Tn_CMP to set the period. > > + * The HPET_TN_SETVAL bit is automatically cleared after the first write. > > + * > > + * For one-shot mode, HPET_TN_SETVAL does not need to be set. > > + * > > + * See the following documents: > > + * - Intel IA-PC HPET (High Precision Event Timers) Specification > > + * - AMD-8111 HyperTransport I/O Hub Data Sheet, Publication # 24674 > > + */ > > +void hpet_set_comparator(int num, unsigned int cmp, unsigned int period) > > +{ > > + if (period) { > > + unsigned int v = hpet_readl(HPET_Tn_CFG(num)); > > + > > + hpet_writel(v | HPET_TN_SETVAL, HPET_Tn_CFG(num)); > > + } > > + > > + hpet_writel(cmp, HPET_Tn_CMP(num)); > > + > > + if (!period) > > + return; > > TBH, I hate this conditional handling. What's wrong with two functions? There is probably nothing wrong with two functions. I can split it into hpet_set_comparator_periodic() and hpet_set_comparator(). Perhaps the latter is not needed as it would be a one-line function; you have suggested earlier to avoid such small functions. > > > + > > + /* > > + * This delay is seldom used: never in one-shot mode and in periodic > > + * only when reprogramming the timer. > > + */ > > + udelay(1); > > + hpet_writel(period, HPET_Tn_CMP(num)); > > +} > > +EXPORT_SYMBOL_GPL(hpet_set_comparator); > > Why is this exported? Which module user needs this? It is not used anywhere else. I will remove this export. Thanks and BR, Ricardo _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu
next prev parent reply other threads:[~2019-06-18 22:48 UTC|newest] Thread overview: 116+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-24 1:16 [RFC PATCH v4 00/21] Implement an HPET-based hardlockup detector Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 01/21] x86/msi: Add definition for NMI delivery mode Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 02/21] x86/hpet: Expose hpet_writel() in header Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 03/21] x86/hpet: Calculate ticks-per-second in a separate function Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-14 15:54 ` Thomas Gleixner 2019-06-14 15:54 ` Thomas Gleixner 2019-06-14 15:59 ` Thomas Gleixner 2019-06-14 15:59 ` Thomas Gleixner 2019-06-18 22:48 ` Ricardo Neri 2019-06-18 22:48 ` Ricardo Neri 2019-06-18 23:13 ` Thomas Gleixner 2019-06-18 23:13 ` Thomas Gleixner 2019-05-24 1:16 ` [RFC PATCH v4 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-14 18:17 ` Thomas Gleixner 2019-06-14 18:17 ` Thomas Gleixner 2019-06-18 22:48 ` Ricardo Neri [this message] 2019-06-18 22:48 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 05/21] x86/hpet: Reserve timer for the HPET hardlockup detector Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-11 19:54 ` Thomas Gleixner 2019-06-11 19:54 ` Thomas Gleixner 2019-06-14 1:14 ` Ricardo Neri 2019-06-14 1:14 ` Ricardo Neri 2019-06-14 16:10 ` Thomas Gleixner 2019-06-14 16:10 ` Thomas Gleixner 2019-06-18 22:48 ` Ricardo Neri 2019-06-18 22:48 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 06/21] x86/hpet: Configure the timer used by the " Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 07/21] watchdog/hardlockup: Define a generic function to detect hardlockups Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 08/21] watchdog/hardlockup: Decouple the hardlockup detector from perf Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 09/21] x86/nmi: Add a NMI_WATCHDOG NMI handler category Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 10/21] watchdog/hardlockup: Add function to enable NMI watchdog on all allowed CPUs at once Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 10/21] watchdog/hardlockup: Add function to enable NMI watchdog on all allowed CPUs at Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 11/21] x86/watchdog/hardlockup: Add an HPET-based hardlockup detector Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 12/21] watchdog/hardlockup/hpet: Adjust timer expiration on the number of monitored CPUs Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-11 20:11 ` Thomas Gleixner 2019-06-11 20:11 ` Thomas Gleixner 2019-06-18 22:46 ` Ricardo Neri 2019-06-18 22:46 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 13/21] x86/watchdog/hardlockup/hpet: Determine if HPET timer caused NMI Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 14/21] watchdog/hardlockup: Use parse_option_str() to handle "nmi_watchdog" Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 15/21] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 16/21] x86/watchdog: Add a shim hardlockup detector Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 17/21] x86/tsc: Switch to perf-based hardlockup detector if TSC become unstable Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-07 0:35 ` Stephane Eranian 2019-06-07 0:35 ` Stephane Eranian via iommu 2019-06-07 14:14 ` Ricardo Neri 2019-06-07 14:14 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 18/21] x86/apic: Add a parameter for the APIC delivery mode Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-16 9:55 ` Thomas Gleixner 2019-06-16 9:55 ` Thomas Gleixner 2019-06-18 22:47 ` Ricardo Neri 2019-06-18 22:47 ` Ricardo Neri 2019-06-18 23:15 ` Thomas Gleixner 2019-06-18 23:15 ` Thomas Gleixner 2019-05-24 1:16 ` [RFC PATCH v4 19/21] iommu/vt-d: Rework prepare_irte() to support per-irq " Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 20/21] iommu/vt-d: hpet: Reserve an interrupt remampping table entry for watchdog Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-16 18:42 ` Thomas Gleixner 2019-06-16 18:42 ` Thomas Gleixner 2019-06-16 19:21 ` Thomas Gleixner 2019-06-16 19:21 ` Thomas Gleixner 2019-06-17 8:25 ` Thomas Gleixner 2019-06-17 8:25 ` Thomas Gleixner 2019-06-17 21:38 ` Stephane Eranian 2019-06-17 21:38 ` Stephane Eranian via iommu 2019-06-17 23:08 ` Thomas Gleixner 2019-06-17 23:08 ` Thomas Gleixner 2019-06-19 15:43 ` Jacob Pan 2019-06-19 15:43 ` Jacob Pan 2019-06-21 15:33 ` Thomas Gleixner 2019-06-21 15:33 ` Thomas Gleixner 2019-06-21 17:31 ` Jacob Pan 2019-06-21 17:31 ` Jacob Pan 2019-06-21 18:39 ` Jacob Pan 2019-06-21 18:39 ` Jacob Pan 2019-06-21 20:05 ` Thomas Gleixner 2019-06-21 20:05 ` Thomas Gleixner 2019-06-21 23:55 ` Ricardo Neri 2019-06-21 23:55 ` Ricardo Neri 2019-06-22 7:21 ` Thomas Gleixner 2019-06-22 7:21 ` Thomas Gleixner 2019-10-18 2:48 ` Ricardo Neri 2019-10-18 2:48 ` Ricardo Neri 2019-06-18 22:45 ` Ricardo Neri 2019-06-18 22:45 ` Ricardo Neri 2019-05-24 1:16 ` [RFC PATCH v4 21/21] x86/watchdog/hardlockup/hpet: Support interrupt remapping Ricardo Neri 2019-05-24 1:16 ` Ricardo Neri 2019-06-16 8:44 ` Thomas Gleixner 2019-06-16 8:44 ` Thomas Gleixner 2019-06-16 8:53 ` Thomas Gleixner 2019-06-16 8:53 ` Thomas Gleixner
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