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 3E3A1105F7A6 for ; Fri, 13 Mar 2026 14:49:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=9T9jNennlerLe3uuA03n7ak9JRhdsHnnl0b5uLOkty4=; b=DvHiKH74JidSw0ce79trZVePU1 Wwn29V5IGE/8LZtx0KCTBjiZJ9cftZKW3OgqDZAckQUXz/hOrdkFXbTHZ5dFVOdbjQ4RnX7Sh+goD dOUsUZrGDt1PrznuWHJcj/FxwG7Boum0PZPHvoAqoocr7sqlxwRJoGX0oFI1OLGYfycb4AIivarSS PiOBN/ttPR00Cdbna3SVeFMHRmhtGaXkl5L6ork05NXmXIYhK8rW0FXvqhiivBDe9bRuUDrP6bEY7 8/3/3bIrC8RNqJUW2AI3XknGj213FAfhaPcKhGxMO2ccPHDBPsj3RlSI84eg0SjaBV07pws37lKiF H3+rY97Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13pR-00000000T3F-3cXJ; Fri, 13 Mar 2026 14:49:29 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13pJ-00000000SvF-1v5E for linux-arm-kernel@bombadil.infradead.org; Fri, 13 Mar 2026 14:49:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=9T9jNennlerLe3uuA03n7ak9JRhdsHnnl0b5uLOkty4=; b=cG04/QEFBfsid6zgUnKu/uvzyy fvFK2jvD+SwdtoVqhrKzlV4XZO7MHC+VLiZr5G+1VF3eDRhzZPW7a7cAk16lp60TXOoZshH6AblaN fkWCr2Q0GQkTsZr+6qoA2A+Wu3tZsxmSR9auzH5jparOd++V2YcCK+EDUMWbF13Wk1ir97azkOd7d slVP7G5cfi1vwayCNn1VHjnyaknL7mDu/kMj/hV96j/eFc1OcBCCVxtistzqYR/UVaqnsCZNaCjZP MwTOOMWyNczNvoFwJC0EBhiRWO3ph6lgAj8zFxReOH8bp6+RAStp0KgppUvSbY4oT4oOQe98KD//x QSt6Xffw==; Received: from foss.arm.com ([217.140.110.172]) by desiato.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w13pF-00000003aJQ-1UVi for linux-arm-kernel@lists.infradead.org; Fri, 13 Mar 2026 14:49:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 29F0425DD; Fri, 13 Mar 2026 07:49:10 -0700 (PDT) Received: from e134344.cambridge.arm.com (e134344.arm.com [10.1.196.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 764B13F7BD; Fri, 13 Mar 2026 07:49:12 -0700 (PDT) From: Ben Horgan To: ben.horgan@arm.com Cc: amitsinght@marvell.com, baisheng.gao@unisoc.com, baolin.wang@linux.alibaba.com, carl@os.amperecomputing.com, dave.martin@arm.com, david@kernel.org, dfustini@baylibre.com, fenghuay@nvidia.com, gshan@redhat.com, james.morse@arm.com, jonathan.cameron@huawei.com, kobak@nvidia.com, lcherian@marvell.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, peternewman@google.com, punit.agrawal@oss.qualcomm.com, quic_jiles@quicinc.com, reinette.chatre@intel.com, rohit.mathew@arm.com, scott@os.amperecomputing.com, sdonthineni@nvidia.com, tan.shaopeng@fujitsu.com, xhao@linux.alibaba.com, catalin.marinas@arm.com, will@kernel.org, corbet@lwn.net, maz@kernel.org, oupton@kernel.org, joey.gouly@arm.com, suzuki.poulose@arm.com, kvmarm@lists.linux.dev, zengheng4@huawei.com, linux-doc@vger.kernel.org Subject: [PATCH v6 39/40] arm_mpam: Quirk CMN-650's CSU NRDY behaviour Date: Fri, 13 Mar 2026 14:46:16 +0000 Message-ID: <20260313144617.3420416-40-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260313144617.3420416-1-ben.horgan@arm.com> References: <20260313144617.3420416-1-ben.horgan@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260313_144918_103828_FE93B39B X-CRM114-Status: GOOD ( 14.52 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: James Morse CMN-650 is afflicted with an erratum where the CSU NRDY bit never clears. This tells us the monitor never finishes scanning the cache. The erratum document says to wait the maximum time, then ignore the field. Add a flag to indicate whether this is the final attempt to read the counter, and when this quirk is applied, ignore the NRDY field. This means accesses to this counter will always retry, even if the counter was previously programmed to the same values. The counter value is not expected to be stable, it drifts up and down with each allocation and eviction. The CSU register provides the value for a point in time. Reviewed-by: Zeng Heng Signed-off-by: James Morse Signed-off-by: Ben Horgan --- Changes since v3: parentheses in macro --- Documentation/arch/arm64/silicon-errata.rst | 3 +++ drivers/resctrl/mpam_devices.c | 12 ++++++++++++ drivers/resctrl/mpam_internal.h | 6 ++++++ 3 files changed, 21 insertions(+) diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index 1aa3326bb320..65ed6ea33751 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -214,6 +214,9 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | ARM | SI L1 | #4311569 | ARM64_ERRATUM_4311569 | +----------------+-----------------+-----------------+-----------------------------+ +| ARM | CMN-650 | #3642720 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ ++----------------+-----------------+-----------------+-----------------------------+ | Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_845719 | +----------------+-----------------+-----------------+-----------------------------+ | Broadcom | Brahma-B53 | N/A | ARM64_ERRATUM_843419 | diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index b6f68ddae8bc..02518b455c89 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -691,6 +691,12 @@ static const struct mpam_quirk mpam_quirks[] = { .iidr_mask = MPAM_IIDR_MATCH_ONE, .workaround = T241_MBW_COUNTER_SCALE_64, }, + { + /* ARM CMN-650 CSU erratum 3642720 */ + .iidr = MPAM_IIDR_ARM_CMN_650, + .iidr_mask = MPAM_IIDR_MATCH_ONE, + .workaround = IGNORE_CSU_NRDY, + }, { NULL } /* Sentinel */ }; @@ -1003,6 +1009,7 @@ struct mon_read { enum mpam_device_features type; u64 *val; int err; + bool waited_timeout; }; static bool mpam_ris_has_mbwu_long_counter(struct mpam_msc_ris *ris) @@ -1249,6 +1256,10 @@ static void __ris_msmon_read(void *arg) if (mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, rprops)) nrdy = now & MSMON___NRDY; now = FIELD_GET(MSMON___VALUE, now); + + if (mpam_has_quirk(IGNORE_CSU_NRDY, msc) && m->waited_timeout) + nrdy = false; + break; case mpam_feat_msmon_mbwu_31counter: case mpam_feat_msmon_mbwu_44counter: @@ -1386,6 +1397,7 @@ int mpam_msmon_read(struct mpam_component *comp, struct mon_cfg *ctx, .ctx = ctx, .type = type, .val = val, + .waited_timeout = true, }; *val = 0; diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 1c9e07955fc8..dbb99d9b0795 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -226,6 +226,7 @@ enum mpam_device_quirks { T241_SCRUB_SHADOW_REGS, T241_FORCE_MBW_MIN_TO_ONE, T241_MBW_COUNTER_SCALE_64, + IGNORE_CSU_NRDY, MPAM_QUIRK_LAST }; @@ -251,6 +252,11 @@ struct mpam_quirk { FIELD_PREP_CONST(MPAMF_IIDR_REVISION, 0) | \ FIELD_PREP_CONST(MPAMF_IIDR_IMPLEMENTER, 0x36b)) +#define MPAM_IIDR_ARM_CMN_650 (FIELD_PREP_CONST(MPAMF_IIDR_PRODUCTID, 0) | \ + FIELD_PREP_CONST(MPAMF_IIDR_VARIANT, 0) | \ + FIELD_PREP_CONST(MPAMF_IIDR_REVISION, 0) | \ + FIELD_PREP_CONST(MPAMF_IIDR_IMPLEMENTER, 0x43b)) + /* The values for MSMON_CFG_MBWU_FLT.RWBW */ enum mon_filter_options { COUNT_BOTH = 0, -- 2.43.0