From patchwork Tue Aug 24 16:47:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D, Lakshmi Sowjanya" X-Patchwork-Id: 501984 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham 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 D5E6BC43214 for ; Tue, 24 Aug 2021 16:48:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C04E861183 for ; Tue, 24 Aug 2021 16:48:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233028AbhHXQtS (ORCPT ); Tue, 24 Aug 2021 12:49:18 -0400 Received: from mga02.intel.com ([134.134.136.20]:10241 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233027AbhHXQtR (ORCPT ); Tue, 24 Aug 2021 12:49:17 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10086"; a="204550726" X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="204550726" Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Aug 2021 09:48:32 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.84,347,1620716400"; d="scan'208";a="684036842" Received: from inlubt0177.iind.intel.com ([10.223.67.91]) by fmsmga006.fm.intel.com with ESMTP; 24 Aug 2021 09:48:30 -0700 From: lakshmi.sowjanya.d@intel.com To: linus.walleij@linaro.org Cc: linux-gpio@vger.kernel.org, bgolaszewski@baylibre.com, linux-kernel@vger.kernel.org, mgross@linux.intel.com, andriy.shevchenko@linux.intel.com, tamal.saha@intel.com, bala.senthil@intel.com, lakshmi.sowjanya.d@intel.com Subject: [RFC PATCH v1 09/20] arch: x86: Add TSC to ART translation Date: Tue, 24 Aug 2021 22:17:50 +0530 Message-Id: <20210824164801.28896-10-lakshmi.sowjanya.d@intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210824164801.28896-1-lakshmi.sowjanya.d@intel.com> References: <20210824164801.28896-1-lakshmi.sowjanya.d@intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Lakshmi Sowjanya D Add a function to convert TSC(Time Stamp Capture) time to ART. The Intel(R) PMC Timed I/O device uses ART to trigger output events. The TSC to ART translation converts the TSC value yielded by ktime_convert_real_to_system_counter() to ART. The conversion is required to program the COMPV register that will be compared against the art time to generate output events. Co-developed-by: Christopher Hall Signed-off-by: Christopher Hall Signed-off-by: Tamal Saha Signed-off-by: Lakshmi Sowjanya D Reviewed-by: Mark Gross --- arch/x86/include/asm/tsc.h | 3 +++ arch/x86/kernel/tsc.c | 35 ++++++++++++++++++++++++++++------- 2 files changed, 31 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index a50b0102e5c1..f1de7ede3ec9 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -8,6 +8,8 @@ #include #include +struct system_counterval_t; + /* * Standard way to access the cycle counter. */ @@ -29,6 +31,7 @@ static inline cycles_t get_cycles(void) } extern u64 read_art_time(void); +extern int convert_tsc_to_art(const struct system_counterval_t *tsc, u64 *art); extern struct system_counterval_t convert_art_to_tsc(u64 art); extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns); diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index bbab6cf1a73b..040109228100 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1231,22 +1231,43 @@ int unsynchronized_tsc(void) } /* - * Converts the current TSC to the current ART value using conversion + * Converts input TSC to the corresponding ART value using conversion * factors discovered by detect_art() */ -u64 read_art_time(void) +int convert_tsc_to_art(const struct system_counterval_t *system_counter, u64 *art) { - u64 tsc, tmp, res, rem; + u64 tmp, res, rem; + + if (system_counter->cs != art_related_clocksource) + return -EINVAL; - tsc = read_tsc(NULL) - art_to_tsc_offset; - rem = do_div(tsc, art_to_tsc_numerator); + res = system_counter->cycles - art_to_tsc_offset; + rem = do_div(res, art_to_tsc_numerator); - res = tsc * art_to_tsc_denominator; + *art = res * art_to_tsc_denominator; tmp = rem * art_to_tsc_denominator; do_div(tmp, art_to_tsc_numerator); + *art += tmp; + + return 0; +} +EXPORT_SYMBOL(convert_tsc_to_art); + +/* + * Converts the current TSC to the current ART value using conversion + * factors discovered by detect_art() + */ +u64 read_art_time(void) +{ + struct system_counterval_t tsc; + u64 art = 0; + + tsc.cs = art_related_clocksource; + tsc.cycles = read_tsc(NULL); + convert_tsc_to_art(&tsc, &art); - return res + tmp; + return art; } EXPORT_SYMBOL(read_art_time);