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[90.63.244.31]) by smtp.gmail.com with ESMTPSA id 133sm7971860wmb.24.2021.10.21.05.19.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 05:19:53 -0700 (PDT) References: <20211016145939.15643-1-martin.blumenstingl@googlemail.com> <1j5ytuvdmw.fsf@starbuckisacylon.baylibre.com> <1jmtn6tu99.fsf@starbuckisacylon.baylibre.com> User-agent: mu4e 1.6.7; emacs 27.1 From: Jerome Brunet To: Martin Blumenstingl Cc: linux-amlogic@lists.infradead.org, Neil Armstrong , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Christian Hewitt Subject: Re: [PATCH] clk: meson: gxbb: Add the spread spectrum bit for MPLL0 on GXBB Date: Thu, 21 Oct 2021 14:18:01 +0200 In-reply-to: Message-ID: <1jfssumuxi.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 20 Oct 2021 at 20:16, Martin Blumenstingl wrote: > Hi Jerome, > > On Mon, Oct 18, 2021 at 2:03 PM Jerome Brunet wrote: > [...] >> > The difference here is BIT(14). un-setting BIT(14) (documented as >> > EN_DDS0) did not change anything according to Christian's test. >> > That also means that SDM, SDM_EN and N2 have the expected values. >> > I manually did the maths: >> > (2000000000Hz * 16384) / ((16384 * 6) + 12808) = 294909640.7Hz >> > which matches what clk_summary sees: >> > 294909641Hz >> >> ... and (2000000000Hz * 16384) / ((16384 * 6) = 333MHz which is fairly close >> to what you get w/o flipping the bit > This is actually a great hint. So far MPLL clocks have "just worked" > for me and I didn't have to work with this. > With your explanation it makes sense that SDM_EN makes the hardware > use or ignore the SDM value. > > [...] >> For example yes. I am asking check a bit more what this bit does and >> what it does not: >> - I need confirmation whether or not it does spread spectrum. Yes this >> needs to be observed on a SoC pin, like MCLK with a fairly low divider >> to the averaging effect which could partially mask spread spectrum. > I did some more tests with Christian. It turns out that on GXBB > HHI_MPLL_CNTL7[15] has no impact on the rate seen by meson-clk-msr. > On the other hand, HHI_MPLL_CNTL[25] makes MPLL0 use or ignore the SDM > value (again, verified through meson-clk-msr). > >> - Get an idea what it actually does. The 2 calculations above are an >> hint. (Spread spectrum does not change the rate mean value) > Indeed! > My conclusion is that on GXBB: > 1) HHI_MPLL_CNTL[25] doesn't control the spread spectrum setting of > MPLL0 - just like you thought > 2) HHI_MPLL_CNTL[25] is actually SDM_EN (and HHI_MPLL_CNTL7[15] > doesn't seem to have any impact on MPLL0's output rate) > > Please let me know if there's anything else we can test. > Else I'll send a patch for making HHI_MPLL_CNTL[25] the SDM_EN bit of > MPLL0 on GXBB. Fine by me if you are confident that HHI_MPLL_CNTL7[15] has indeed no effect. Maybe add a comment about this oddity. > > > Best regards, > Martin 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A8490C433F5 for ; Thu, 21 Oct 2021 12:20:06 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 237E961221 for ; Thu, 21 Oct 2021 12:20:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 237E961221 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-reply-to: Date:Subject:Cc:To:From:References:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZkNjQHBXR7sKEoJCPScEsTbCYhbqbeGSMXsDlnFIbqo=; b=r48lAL265DNdgf 7TkkVnKnoHeoN/DT6SEZgGnxd4MxvSLs0pVJlsTFTjpxJSyhhOPLuw/p8pAPgwj7nCSxWKcmVRGIE HBjqQIsArSaEjMUhugkw3CAlcqMkj/NUDsHVB1M+4LjWpSjdwIEZT18tCO/RI9i4OWW7ZG9Ygk1/0 WRwzoDX/FW7f6dtHMuyLDbpFLo7+2/Dp3ZsAcgEUgIaOZsSzjX1yb8KDi6DxRByxzFOWSzNh9qd7m lHKie+yxIyN+ARjqd9yApvGrWGh1pioBtLjjPbpW3uH027AdSJeJIZ2i3tPwJ+X5FcIMmuFQmb/EU F2dlIEu4UubFNU5TMsyw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdX3A-007RrP-2l; Thu, 21 Oct 2021 12:20:00 +0000 Received: from mail-wr1-x42f.google.com ([2a00:1450:4864:20::42f]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdX36-007RpG-O8 for linux-amlogic@lists.infradead.org; Thu, 21 Oct 2021 12:19:59 +0000 Received: by mail-wr1-x42f.google.com with SMTP id r7so732414wrc.10 for ; Thu, 21 Oct 2021 05:19:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20210112.gappssmtp.com; s=20210112; h=references:user-agent:from:to:cc:subject:date:in-reply-to :message-id:mime-version; bh=1MAcWNR4eIJHPkpF0pYcakZ/CD1b8OAEZ6esT1QDubc=; b=hBCnOWpAXWArLg0uH9UGShDwvTdqrT6J/fDuC7xhthw0qa2wBVNACShsI7AISgfR+d YJIVZHIJPWeNFDiq2VIA+I///w1zDmM5lO2OWmh9154MduFB2OM8IhFLstq+rvPCmTTj AecQMUgLfL7ChrRfMLg/mNhdLPy1a4IxlgTb33oc6uytvUdukI63bZhtEYHVnEXLbWkD OE9r4iwGFvJIRzMDWVfad0JxcBuig+jD6hK518WZWIHfAicg0CstlGMEM5jHiD8E3pSE pFiZx0isZAP5kHfk+EPvELt6K0hFc+4j3i7TBbr9LAffw8aCWZIjAequzLZy9FP46rPy V1AA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:references:user-agent:from:to:cc:subject:date :in-reply-to:message-id:mime-version; bh=1MAcWNR4eIJHPkpF0pYcakZ/CD1b8OAEZ6esT1QDubc=; b=wPnVOqJ6oxDaPIaNZUOKmbRaXLPwDnnRID+h4d2T+hlMOpuWrIiqkxdnydYuPCNlRm 15DLTFSZOyxu9Fx77tfRCG/s4sX+Clu/EzGI9fl2+QkrWVN3yfFTYkXvODGsxdZ3u+mL hMDNMlH+tTJFIvDSQ77qw3zZCqsvGB+zw6ERrnoLGDYPr3s+En/kUrPXnwJhOglVioZM sabFUP+qbYqTw7jpBDPmd1o573Kxg82qfrV8TlFjMpFrepGzvXYSlWuRXjvkb7siUwz8 3pWDeqXGQLMLsIV4Bs0qQsY/HIIHV7YzyCU2deb1WsK2z+X3KuW2W6uiQBReqOzwo9tW s1iA== X-Gm-Message-State: AOAM5322UqZYb8y06dfOJ1Pt0HNud6uGnSJ95+TB3V2GR/WWNKEAameD 4miZb4V34nqteDijy56TqRzxfw== X-Google-Smtp-Source: ABdhPJzJvoUSpjaqHzOXELw1I39FiK/03T2TYTk/qaJuwZGyqBujn5meTTPNaXiPnO9TLEbK6mN7ZQ== X-Received: by 2002:adf:ff91:: with SMTP id j17mr6555798wrr.132.1634818794258; Thu, 21 Oct 2021 05:19:54 -0700 (PDT) Received: from localhost (laubervilliers-658-1-213-31.w90-63.abo.wanadoo.fr. [90.63.244.31]) by smtp.gmail.com with ESMTPSA id 133sm7971860wmb.24.2021.10.21.05.19.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 05:19:53 -0700 (PDT) References: <20211016145939.15643-1-martin.blumenstingl@googlemail.com> <1j5ytuvdmw.fsf@starbuckisacylon.baylibre.com> <1jmtn6tu99.fsf@starbuckisacylon.baylibre.com> User-agent: mu4e 1.6.7; emacs 27.1 From: Jerome Brunet To: Martin Blumenstingl Cc: linux-amlogic@lists.infradead.org, Neil Armstrong , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Christian Hewitt Subject: Re: [PATCH] clk: meson: gxbb: Add the spread spectrum bit for MPLL0 on GXBB Date: Thu, 21 Oct 2021 14:18:01 +0200 In-reply-to: Message-ID: <1jfssumuxi.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211021_051956_890687_E02C33AF X-CRM114-Status: GOOD ( 23.81 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On Wed 20 Oct 2021 at 20:16, Martin Blumenstingl wrote: > Hi Jerome, > > On Mon, Oct 18, 2021 at 2:03 PM Jerome Brunet wrote: > [...] >> > The difference here is BIT(14). un-setting BIT(14) (documented as >> > EN_DDS0) did not change anything according to Christian's test. >> > That also means that SDM, SDM_EN and N2 have the expected values. >> > I manually did the maths: >> > (2000000000Hz * 16384) / ((16384 * 6) + 12808) = 294909640.7Hz >> > which matches what clk_summary sees: >> > 294909641Hz >> >> ... and (2000000000Hz * 16384) / ((16384 * 6) = 333MHz which is fairly close >> to what you get w/o flipping the bit > This is actually a great hint. So far MPLL clocks have "just worked" > for me and I didn't have to work with this. > With your explanation it makes sense that SDM_EN makes the hardware > use or ignore the SDM value. > > [...] >> For example yes. I am asking check a bit more what this bit does and >> what it does not: >> - I need confirmation whether or not it does spread spectrum. Yes this >> needs to be observed on a SoC pin, like MCLK with a fairly low divider >> to the averaging effect which could partially mask spread spectrum. > I did some more tests with Christian. It turns out that on GXBB > HHI_MPLL_CNTL7[15] has no impact on the rate seen by meson-clk-msr. > On the other hand, HHI_MPLL_CNTL[25] makes MPLL0 use or ignore the SDM > value (again, verified through meson-clk-msr). > >> - Get an idea what it actually does. The 2 calculations above are an >> hint. (Spread spectrum does not change the rate mean value) > Indeed! > My conclusion is that on GXBB: > 1) HHI_MPLL_CNTL[25] doesn't control the spread spectrum setting of > MPLL0 - just like you thought > 2) HHI_MPLL_CNTL[25] is actually SDM_EN (and HHI_MPLL_CNTL7[15] > doesn't seem to have any impact on MPLL0's output rate) > > Please let me know if there's anything else we can test. > Else I'll send a patch for making HHI_MPLL_CNTL[25] the SDM_EN bit of > MPLL0 on GXBB. Fine by me if you are confident that HHI_MPLL_CNTL7[15] has indeed no effect. Maybe add a comment about this oddity. > > > Best regards, > Martin _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2E99C433F5 for ; Thu, 21 Oct 2021 12:21:22 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id C12A16124D for ; Thu, 21 Oct 2021 12:21:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org C12A16124D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=baylibre.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:In-reply-to: Date:Subject:Cc:To:From:References:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=i3eDM2AHWAKkBPXaRaoP/MH/ek28DpOZt8zOgNWY2Ic=; b=tsATqT+FVMXg6r +grKQlQ6zdrZGL3fyvrGSCut5Tk3rGKtmY3Y19WGriAlH4AO1KOUog6tvVDHObIyKjNTtsJpnPJMy 4R7wrtQoWbM0R3RJdUG2EAbzRkg1ShmL3MiGPZC10o+1sdHZkWXbHBPnxxvw1NpSl+2plPCUhpb9S E1o+LDqLwRDq5fDjPp7MMnz0Um0/bFD61SN5nLVStadHB0Bb0rQcA9B3XK9EIOF9ehxqCgBbUJxYC h6LrBaKeoUOJdq5piHfWZfohjPBY/pHlGl6sO3M4E/E0i0oMo5wnOa0uS7Oq83+Vajcg/cglHEqx9 fqAzcm7wSWIbegakpjSQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdX3C-007Rrg-Rj; Thu, 21 Oct 2021 12:20:03 +0000 Received: from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mdX36-007RpF-Sb for linux-arm-kernel@lists.infradead.org; Thu, 21 Oct 2021 12:19:59 +0000 Received: by mail-wr1-x42b.google.com with SMTP id y3so844446wrl.1 for ; Thu, 21 Oct 2021 05:19:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=baylibre-com.20210112.gappssmtp.com; s=20210112; h=references:user-agent:from:to:cc:subject:date:in-reply-to :message-id:mime-version; bh=1MAcWNR4eIJHPkpF0pYcakZ/CD1b8OAEZ6esT1QDubc=; b=hBCnOWpAXWArLg0uH9UGShDwvTdqrT6J/fDuC7xhthw0qa2wBVNACShsI7AISgfR+d YJIVZHIJPWeNFDiq2VIA+I///w1zDmM5lO2OWmh9154MduFB2OM8IhFLstq+rvPCmTTj AecQMUgLfL7ChrRfMLg/mNhdLPy1a4IxlgTb33oc6uytvUdukI63bZhtEYHVnEXLbWkD OE9r4iwGFvJIRzMDWVfad0JxcBuig+jD6hK518WZWIHfAicg0CstlGMEM5jHiD8E3pSE pFiZx0isZAP5kHfk+EPvELt6K0hFc+4j3i7TBbr9LAffw8aCWZIjAequzLZy9FP46rPy V1AA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:references:user-agent:from:to:cc:subject:date :in-reply-to:message-id:mime-version; bh=1MAcWNR4eIJHPkpF0pYcakZ/CD1b8OAEZ6esT1QDubc=; b=WUBIUF+VEuAHUaopPOOY3dOIohUboRkbQGuh8R9Mei1/OxGylfuV/C4w/5/Ihrk5d8 g+Ghz196sqv+GFzljZkkVvipszUo1e7IosD+8P6uyooraHYqXD/vnMWLCBFzGPtC8DLj dvmHoNbO+29YjyWludtOtHU0iSSyvTYkRRMClaJIzIz6KT8Q/j8AcodJ3hKgo69IFLhg dtwOlgkBOswEaRIOAZ4BgiCwshTDNVpd2RseYUbOT5YNg1HGxmICcj9rPQ/UMnY4QZKU Nlv3uqLqT5xY1Tkq2VI4zQli+SOUgjHE+BeJoHNqb9/OcbQDbVvgGy/hbTYPvfq7ATHA lrYw== X-Gm-Message-State: AOAM530SUux29qTlF0H0DrcBTXoifWT9qJdUfigP1wZfPJ4SNXnirfGZ UlG410tMM5x451zDzmRMkRY2QQ== X-Google-Smtp-Source: ABdhPJzJvoUSpjaqHzOXELw1I39FiK/03T2TYTk/qaJuwZGyqBujn5meTTPNaXiPnO9TLEbK6mN7ZQ== X-Received: by 2002:adf:ff91:: with SMTP id j17mr6555798wrr.132.1634818794258; Thu, 21 Oct 2021 05:19:54 -0700 (PDT) Received: from localhost (laubervilliers-658-1-213-31.w90-63.abo.wanadoo.fr. [90.63.244.31]) by smtp.gmail.com with ESMTPSA id 133sm7971860wmb.24.2021.10.21.05.19.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Oct 2021 05:19:53 -0700 (PDT) References: <20211016145939.15643-1-martin.blumenstingl@googlemail.com> <1j5ytuvdmw.fsf@starbuckisacylon.baylibre.com> <1jmtn6tu99.fsf@starbuckisacylon.baylibre.com> User-agent: mu4e 1.6.7; emacs 27.1 From: Jerome Brunet To: Martin Blumenstingl Cc: linux-amlogic@lists.infradead.org, Neil Armstrong , linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Christian Hewitt Subject: Re: [PATCH] clk: meson: gxbb: Add the spread spectrum bit for MPLL0 on GXBB Date: Thu, 21 Oct 2021 14:18:01 +0200 In-reply-to: Message-ID: <1jfssumuxi.fsf@starbuckisacylon.baylibre.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211021_051956_965117_B6C9CE62 X-CRM114-Status: GOOD ( 25.40 ) 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: , 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 On Wed 20 Oct 2021 at 20:16, Martin Blumenstingl wrote: > Hi Jerome, > > On Mon, Oct 18, 2021 at 2:03 PM Jerome Brunet wrote: > [...] >> > The difference here is BIT(14). un-setting BIT(14) (documented as >> > EN_DDS0) did not change anything according to Christian's test. >> > That also means that SDM, SDM_EN and N2 have the expected values. >> > I manually did the maths: >> > (2000000000Hz * 16384) / ((16384 * 6) + 12808) = 294909640.7Hz >> > which matches what clk_summary sees: >> > 294909641Hz >> >> ... and (2000000000Hz * 16384) / ((16384 * 6) = 333MHz which is fairly close >> to what you get w/o flipping the bit > This is actually a great hint. So far MPLL clocks have "just worked" > for me and I didn't have to work with this. > With your explanation it makes sense that SDM_EN makes the hardware > use or ignore the SDM value. > > [...] >> For example yes. I am asking check a bit more what this bit does and >> what it does not: >> - I need confirmation whether or not it does spread spectrum. Yes this >> needs to be observed on a SoC pin, like MCLK with a fairly low divider >> to the averaging effect which could partially mask spread spectrum. > I did some more tests with Christian. It turns out that on GXBB > HHI_MPLL_CNTL7[15] has no impact on the rate seen by meson-clk-msr. > On the other hand, HHI_MPLL_CNTL[25] makes MPLL0 use or ignore the SDM > value (again, verified through meson-clk-msr). > >> - Get an idea what it actually does. The 2 calculations above are an >> hint. (Spread spectrum does not change the rate mean value) > Indeed! > My conclusion is that on GXBB: > 1) HHI_MPLL_CNTL[25] doesn't control the spread spectrum setting of > MPLL0 - just like you thought > 2) HHI_MPLL_CNTL[25] is actually SDM_EN (and HHI_MPLL_CNTL7[15] > doesn't seem to have any impact on MPLL0's output rate) > > Please let me know if there's anything else we can test. > Else I'll send a patch for making HHI_MPLL_CNTL[25] the SDM_EN bit of > MPLL0 on GXBB. Fine by me if you are confident that HHI_MPLL_CNTL7[15] has indeed no effect. Maybe add a comment about this oddity. > > > Best regards, > Martin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel