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 AF84DF4BB69 for ; Tue, 24 Feb 2026 18:01:22 +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=Ztdr/0ZrGuB1B+YkEuWhUxc8alpUJOuDXNNqgIe0sKU=; b=WUv5dLE//OakRS375v4KWGiELw 6dI/H2aqc/UXW1KemWovJewsVeiFCZx8M5iT7EmqT2s04OxdO4zh6o7hmZr3UFpKR4qWKNiMHq//z +bvCmsPq/ZmIVOOQBUF+eOkSmIy/6XrL1s9KW6uPiL1thWj88v5EWgjsQLr81Wr9cGBIGpNCgIWya AOdygHAuBYWCalBf0BnaP/3ugPMLQ68i9XnGTzhEYVvubEIv5qHCBlEUNOONnvPXyutmj9k/c9cvv gO3NXFchfg+uGluLZRJWd4Qm4PJFFzxRT6oPqBHixjROt66Mb8N/u14l49NNJ7SBTPWpBvyuPssYF 7WfNykWQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vuwii-00000002aVb-0AZn; Tue, 24 Feb 2026 18:01:16 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vuwid-00000002aRH-3pIY for linux-arm-kernel@lists.infradead.org; Tue, 24 Feb 2026 18:01:13 +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 0F9E01595; Tue, 24 Feb 2026 10:01:05 -0800 (PST) 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 A0D973F59E; Tue, 24 Feb 2026 10:01:05 -0800 (PST) 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, Shaopeng Tan Subject: [PATCH v5 39/41] arm_mpam: Add workaround for T241-MPAM-6 Date: Tue, 24 Feb 2026 17:57:18 +0000 Message-ID: <20260224175720.2663924-40-ben.horgan@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260224175720.2663924-1-ben.horgan@arm.com> References: <20260224175720.2663924-1-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-20260224_100112_068067_724301FA X-CRM114-Status: GOOD ( 18.80 ) 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: Shanker Donthineni The registers MSMON_MBWU_L and MSMON_MBWU return the number of requests rather than the number of bytes transferred. Bandwidth resource monitoring is performed at the last level cache, where each request arrive in 64Byte granularity. The current implementation returns the number of transactions received at the last level cache but does not provide the value in bytes. Scaling by 64 gives an accurate byte count to match the MPAM specification for the MSMON_MBWU and MSMON_MBWU_L registers. This patch fixes the issue by reporting the actual number of bytes instead of the number of transactions from __ris_msmon_read(). Tested-by: Gavin Shan Tested-by: Shaopeng Tan Reviewed-by: Shaopeng Tan Signed-off-by: Shanker Donthineni Signed-off-by: James Morse Signed-off-by: Ben Horgan --- Changes since rfc: MPAM_IIDR_NVIDIA_T421 -> MPAM_IIDR_NVIDIA_T241 Don't apply workaround to MSMON_MBWU_LWD --- Documentation/arch/arm64/silicon-errata.rst | 2 ++ drivers/resctrl/mpam_devices.c | 26 +++++++++++++++++++-- drivers/resctrl/mpam_internal.h | 1 + 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/Documentation/arch/arm64/silicon-errata.rst b/Documentation/arch/arm64/silicon-errata.rst index a4b246655e37..1aa3326bb320 100644 --- a/Documentation/arch/arm64/silicon-errata.rst +++ b/Documentation/arch/arm64/silicon-errata.rst @@ -251,6 +251,8 @@ stable kernels. +----------------+-----------------+-----------------+-----------------------------+ | NVIDIA | T241 MPAM | T241-MPAM-4 | N/A | +----------------+-----------------+-----------------+-----------------------------+ +| NVIDIA | T241 MPAM | T241-MPAM-6 | N/A | ++----------------+-----------------+-----------------+-----------------------------+ +----------------+-----------------+-----------------+-----------------------------+ | Freescale/NXP | LS2080A/LS1043A | A-008585 | FSL_ERRATUM_A008585 | +----------------+-----------------+-----------------+-----------------------------+ diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c index 8f44e9dee207..48a233875a9a 100644 --- a/drivers/resctrl/mpam_devices.c +++ b/drivers/resctrl/mpam_devices.c @@ -685,6 +685,12 @@ static const struct mpam_quirk mpam_quirks[] = { .iidr_mask = MPAM_IIDR_MATCH_ONE, .workaround = T241_FORCE_MBW_MIN_TO_ONE, }, + { + /* NVIDIA t241 erratum T241-MPAM-6 */ + .iidr = MPAM_IIDR_NVIDIA_T241, + .iidr_mask = MPAM_IIDR_MATCH_ONE, + .workaround = T241_MBW_COUNTER_SCALE_64, + }, { NULL } /* Sentinel */ }; @@ -1146,7 +1152,7 @@ static void write_msmon_ctl_flt_vals(struct mon_read *m, u32 ctl_val, } } -static u64 mpam_msmon_overflow_val(enum mpam_device_features type) +static u64 __mpam_msmon_overflow_val(enum mpam_device_features type) { /* TODO: implement scaling counters */ switch (type) { @@ -1161,6 +1167,18 @@ static u64 mpam_msmon_overflow_val(enum mpam_device_features type) } } +static u64 mpam_msmon_overflow_val(enum mpam_device_features type, + struct mpam_msc *msc) +{ + u64 overflow_val = __mpam_msmon_overflow_val(type); + + if (mpam_has_quirk(T241_MBW_COUNTER_SCALE_64, msc) && + type != mpam_feat_msmon_mbwu_63counter) + overflow_val *= 64; + + return overflow_val; +} + static void __ris_msmon_read(void *arg) { u64 now; @@ -1251,13 +1269,17 @@ static void __ris_msmon_read(void *arg) now = FIELD_GET(MSMON___VALUE, now); } + if (mpam_has_quirk(T241_MBW_COUNTER_SCALE_64, msc) && + m->type != mpam_feat_msmon_mbwu_63counter) + now *= 64; + if (nrdy) break; mbwu_state = &ris->mbwu_state[ctx->mon]; if (overflow) - mbwu_state->correction += mpam_msmon_overflow_val(m->type); + mbwu_state->correction += mpam_msmon_overflow_val(m->type, msc); /* * Include bandwidth consumed before the last hardware reset and diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h index 9f92fd49a61c..1443a1dd996e 100644 --- a/drivers/resctrl/mpam_internal.h +++ b/drivers/resctrl/mpam_internal.h @@ -225,6 +225,7 @@ struct mpam_props { enum mpam_device_quirks { T241_SCRUB_SHADOW_REGS, T241_FORCE_MBW_MIN_TO_ONE, + T241_MBW_COUNTER_SCALE_64, MPAM_QUIRK_LAST }; -- 2.43.0