From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7CCB0C04AB6 for ; Tue, 14 May 2019 14:04:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4D32A21537 for ; Tue, 14 May 2019 14:04:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726804AbfENOEU (ORCPT ); Tue, 14 May 2019 10:04:20 -0400 Received: from mga09.intel.com ([134.134.136.24]:59047 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726272AbfENOC6 (ORCPT ); Tue, 14 May 2019 10:02:58 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 May 2019 07:02:57 -0700 X-ExtLoop1: 1 Received: from unknown (HELO luv-build.sc.intel.com) ([172.25.110.25]) by fmsmga005.fm.intel.com with ESMTP; 14 May 2019 07:02:56 -0700 From: Ricardo Neri To: Thomas Gleixner , Ingo Molnar , Borislav Petkov Cc: Ashok Raj , Joerg Roedel , Andi Kleen , Peter Zijlstra , "Ravi V. Shankar" , x86@kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Ricardo Neri , Ricardo Neri , "H. Peter Anvin" , Tony Luck , Philippe Ombredanne , Kate Stewart , "Rafael J. Wysocki" , Stephane Eranian , Suravee Suthikulpanit Subject: [RFC PATCH v3 04/21] x86/hpet: Add hpet_set_comparator() for periodic and one-shot modes Date: Tue, 14 May 2019 07:01:57 -0700 Message-Id: <1557842534-4266-5-git-send-email-ricardo.neri-calderon@linux.intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1557842534-4266-1-git-send-email-ricardo.neri-calderon@linux.intel.com> References: <1557842534-4266-1-git-send-email-ricardo.neri-calderon@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Instead of setting the timer period directly in hpet_set_periodic(), add a new helper function hpet_set_comparator() that only sets the accumulator and comparator. hpet_set_periodic() will only prepare the timer for periodic mode and leave the expiration programming to hpet_set_comparator(). This new function can also be used by other components (e.g., the HPET- based hardlockup detector) which also need to configure HPET timers. Thus, add its declaration into the hpet header file. Cc: "H. Peter Anvin" Cc: Ashok Raj Cc: Andi Kleen Cc: Tony Luck Cc: Philippe Ombredanne Cc: Kate Stewart Cc: "Rafael J. Wysocki" Cc: Stephane Eranian Cc: Suravee Suthikulpanit Cc: "Ravi V. Shankar" Cc: x86@kernel.org Originally-by: Suravee Suthikulpanit Signed-off-by: Ricardo Neri --- arch/x86/include/asm/hpet.h | 1 + arch/x86/kernel/hpet.c | 57 ++++++++++++++++++++++++++++--------- 2 files changed, 45 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/hpet.h b/arch/x86/include/asm/hpet.h index f132fbf984d4..e7098740f5ee 100644 --- a/arch/x86/include/asm/hpet.h +++ b/arch/x86/include/asm/hpet.h @@ -102,6 +102,7 @@ extern int hpet_rtc_timer_init(void); extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id); extern int hpet_register_irq_handler(rtc_irq_handler handler); extern void hpet_unregister_irq_handler(rtc_irq_handler handler); +extern void hpet_set_comparator(int num, unsigned int cmp, unsigned int period); #endif /* CONFIG_HPET_EMULATE_RTC */ diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 560fc28e1d13..c5c5fc150193 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -289,6 +289,46 @@ static void hpet_legacy_clockevent_register(void) printk(KERN_DEBUG "hpet clockevent registered\n"); } +/** + * 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; + + /* 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); + static int hpet_set_periodic(struct clock_event_device *evt, int timer) { unsigned int cfg, cmp, now; @@ -300,19 +340,10 @@ static int hpet_set_periodic(struct clock_event_device *evt, int timer) now = hpet_readl(HPET_COUNTER); cmp = now + (unsigned int)delta; cfg = hpet_readl(HPET_Tn_CFG(timer)); - cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | - HPET_TN_32BIT; - hpet_writel(cfg, HPET_Tn_CFG(timer)); - hpet_writel(cmp, HPET_Tn_CMP(timer)); - udelay(1); - /* - * HPET on AMD 81xx needs a second write (with HPET_TN_SETVAL - * cleared) to T0_CMP to set the period. The HPET_TN_SETVAL - * bit is automatically cleared after the first write. - * (See AMD-8111 HyperTransport I/O Hub Data Sheet, - * Publication # 24674) - */ - hpet_writel((unsigned int)delta, HPET_Tn_CMP(timer)); + cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_32BIT; + + hpet_set_comparator(timer, cmp, (unsigned int)delta); + hpet_start_counter(); hpet_print_config(); -- 2.17.1