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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 00668C46467 for ; Mon, 16 Jan 2023 10:25:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date:Subject:Cc:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=8oOxaQADaideQ5OBYjXFTHWBNkL0rEBoNbpAGkzg7Vg=; b=m5sIf3ltPncL2i VQfj/TyLHAtqg5huUUgRzjAl9zSYRe59jMT3pS72eyu1zYH3kOvZRgrz5xp4V9RCBl4lLoLvYb4j8 oWsvWNtIT9OLVF6unq0p7l8w3DjrWTHFfQbQkbqAXEkj4aOwP1SXFXIX2n0E2KUzEPobsGtmMV7So 0x65fdiaHJ3eeMslgtrYCUs3/6PWi7pT5LeAx/RhbhCgpxdhaz1HR+U+LvtfxU8URngfXQ5/zym8l vJTkGomyl50V3Ci4Loajs7ArnFjwXUufpcBylGF7kHrUQ7QuO37K5Z7k/9mfREhduEcFmVITdqoOm NUY+Zmct6DMc+AGpfx5w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1pHMfd-009dso-5N; Mon, 16 Jan 2023 10:24:53 +0000 Received: from inva021.nxp.com ([92.121.34.21]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1pHMfY-009ds0-TN for linux-arm-kernel@lists.infradead.org; Mon, 16 Jan 2023 10:24:51 +0000 Received: from inva021.nxp.com (localhost [127.0.0.1]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id 142DB2008E1; Mon, 16 Jan 2023 11:24:45 +0100 (CET) Received: from aprdc01srsp001v.ap-rdc01.nxp.com (aprdc01srsp001v.ap-rdc01.nxp.com [165.114.16.16]) by inva021.eu-rdc02.nxp.com (Postfix) with ESMTP id D16392008DF; Mon, 16 Jan 2023 11:24:44 +0100 (CET) Received: from lsv03267.swis.in-blr01.nxp.com (lsv03267.swis.in-blr01.nxp.com [92.120.147.107]) by aprdc01srsp001v.ap-rdc01.nxp.com (Postfix) with ESMTP id CB780183ABEF; Mon, 16 Jan 2023 18:24:43 +0800 (+08) From: nikhil.gupta@nxp.com To: linux-arm-kernel@lists.infradead.org, Yangbo Lu , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: vakul.garg@nxp.com, rajan.gupta@nxp.com, richardcochran@gmail.com, Nikhil Gupta Subject: [PATCH v1] ptp_qoriq: fix latency in ptp_qoriq_adjtime() operation. Date: Mon, 16 Jan 2023 15:54:40 +0530 Message-Id: <20230116102440.27189-1-nikhil.gupta@nxp.com> X-Mailer: git-send-email 2.17.1 X-Virus-Scanned: ClamAV using ClamSMTP X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230116_022449_235073_D10F7766 X-CRM114-Status: UNSURE ( 9.13 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Nikhil Gupta 1588 driver loses about 1us in adjtime operation at PTP slave. This is because adjtime operation uses a slow non-atomic tmr_cnt_read() followed by tmr_cnt_write() operation. In the above sequence, since the timer counter operation keeps incrementing, it leads to latency. The tmr_offset register (which is added to TMR_CNT_H/L register gives the current time) must be programmed with the delta nanoseconds. Signed-off-by: Nikhil Gupta Reviewed-by: Yangbo Lu --- drivers/ptp/ptp_qoriq.c | 35 ++++++++++++++++++++++++++++++----- 1 file changed, 30 insertions(+), 5 deletions(-) diff --git a/drivers/ptp/ptp_qoriq.c b/drivers/ptp/ptp_qoriq.c index 08f4cf0ad9e3..69fa77b99b45 100644 --- a/drivers/ptp/ptp_qoriq.c +++ b/drivers/ptp/ptp_qoriq.c @@ -48,6 +48,29 @@ static void tmr_cnt_write(struct ptp_qoriq *ptp_qoriq, u64 ns) ptp_qoriq->write(®s->ctrl_regs->tmr_cnt_h, hi); } +static void tmr_offset_write(struct ptp_qoriq *ptp_qoriq, u64 delta_ns) +{ + struct ptp_qoriq_registers *regs = &ptp_qoriq->regs; + u32 hi = delta_ns >> 32; + u32 lo = delta_ns & 0xffffffff; + + ptp_qoriq->write(®s->ctrl_regs->tmroff_l, lo); + ptp_qoriq->write(®s->ctrl_regs->tmroff_h, hi); +} + +static u64 tmr_offset_read(struct ptp_qoriq *ptp_qoriq) +{ + struct ptp_qoriq_registers *regs = &ptp_qoriq->regs; + u64 ns; + u32 lo, hi; + + lo = ptp_qoriq->read(®s->ctrl_regs->tmroff_l); + hi = ptp_qoriq->read(®s->ctrl_regs->tmroff_h); + ns = ((u64) hi) << 32; + ns |= lo; + return ns; +} + /* Caller must hold ptp_qoriq->lock. */ static void set_alarm(struct ptp_qoriq *ptp_qoriq) { @@ -55,7 +78,9 @@ static void set_alarm(struct ptp_qoriq *ptp_qoriq) u64 ns; u32 lo, hi; - ns = tmr_cnt_read(ptp_qoriq) + 1500000000ULL; + ns = tmr_cnt_read(ptp_qoriq) + tmr_offset_read(ptp_qoriq) + + 1500000000ULL; + ns = div_u64(ns, 1000000000UL) * 1000000000ULL; ns -= ptp_qoriq->tclk_period; hi = ns >> 32; @@ -212,10 +237,9 @@ int ptp_qoriq_adjtime(struct ptp_clock_info *ptp, s64 delta) struct ptp_qoriq *ptp_qoriq = container_of(ptp, struct ptp_qoriq, caps); spin_lock_irqsave(&ptp_qoriq->lock, flags); - - now = tmr_cnt_read(ptp_qoriq); + now = tmr_offset_read(ptp_qoriq); now += delta; - tmr_cnt_write(ptp_qoriq, now); + tmr_offset_write(ptp_qoriq, now); set_fipers(ptp_qoriq); spin_unlock_irqrestore(&ptp_qoriq->lock, flags); @@ -232,7 +256,7 @@ int ptp_qoriq_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts) spin_lock_irqsave(&ptp_qoriq->lock, flags); - ns = tmr_cnt_read(ptp_qoriq); + ns = tmr_cnt_read(ptp_qoriq) + tmr_offset_read(ptp_qoriq); spin_unlock_irqrestore(&ptp_qoriq->lock, flags); @@ -253,6 +277,7 @@ int ptp_qoriq_settime(struct ptp_clock_info *ptp, spin_lock_irqsave(&ptp_qoriq->lock, flags); + tmr_offset_write(ptp_qoriq, 0); tmr_cnt_write(ptp_qoriq, ns); set_fipers(ptp_qoriq); -- 2.17.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel