From patchwork Tue Dec 24 22:19:21 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anson Huang X-Patchwork-Id: 304927 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Received: from casper.infradead.org (unknown [IPv6:2001:770:15f::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id EDC172C00B7 for ; Tue, 24 Dec 2013 21:21:59 +1100 (EST) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvP7V-00013O-SS; Tue, 24 Dec 2013 10:21:50 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvP7T-0001n3-Gz; Tue, 24 Dec 2013 10:21:47 +0000 Received: from co9ehsobe002.messaging.microsoft.com ([207.46.163.25] helo=co9outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvP7Q-0001mZ-61 for linux-arm-kernel@lists.infradead.org; Tue, 24 Dec 2013 10:21:44 +0000 Received: from mail161-co9-R.bigfish.com (10.236.132.236) by CO9EHSOBE017.bigfish.com (10.236.130.80) with Microsoft SMTP Server id 14.1.225.22; Tue, 24 Dec 2013 10:21:22 +0000 Received: from mail161-co9 (localhost [127.0.0.1]) by mail161-co9-R.bigfish.com (Postfix) with ESMTP id 10B0F1C055F; Tue, 24 Dec 2013 10:21:22 +0000 (UTC) X-Forefront-Antispam-Report: CIP:70.37.183.190; KIP:(null); UIP:(null); IPV:NLI; H:mail.freescale.net; RD:none; EFVD:NLI X-SpamScore: 3 X-BigFish: VS3(zzzz1f42h2148h208ch1ee6h1de0h1fdah2073h2146h1202h1e76h2189h1d1ah1d2ah1fc6h1082kzz1de098h8275bh1de097hz2dh2a8h839hd24he5bhf0ah1288h12a5h12a9h12bdh12e5h137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh2222h224fh1fb3h1d0ch1d2eh1d3fh1dc1h1dfeh1dffh1e23h1fe8h1ff5h2218h2216h226dh22d0h2327h2336h1155h) Received: from mail161-co9 (localhost.localdomain [127.0.0.1]) by mail161-co9 (MessageSwitch) id 1387880480740451_16464; Tue, 24 Dec 2013 10:21:20 +0000 (UTC) Received: from CO9EHSMHS029.bigfish.com (unknown [10.236.132.232]) by mail161-co9.bigfish.com (Postfix) with ESMTP id B079E300046; Tue, 24 Dec 2013 10:21:20 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by CO9EHSMHS029.bigfish.com (10.236.130.39) with Microsoft SMTP Server (TLS) id 14.16.227.3; Tue, 24 Dec 2013 10:21:20 +0000 Received: from tx30smr01.am.freescale.net (10.81.153.31) by 039-SN1MMR1-001.039d.mgd.msft.net (10.84.1.13) with Microsoft SMTP Server (TLS) id 14.3.158.2; Tue, 24 Dec 2013 10:21:19 +0000 Received: from ubuntu.ap.freescale.net (ubuntu-010192242118.ap.freescale.net [10.192.242.118]) by tx30smr01.am.freescale.net (8.14.3/8.14.0) with ESMTP id rBOALGht016814; Tue, 24 Dec 2013 03:21:18 -0700 From: Anson Huang To: , Subject: [PATCH V2] ARM: imx: improve the comment of CCM lpm SW workaround Date: Tue, 24 Dec 2013 17:19:21 -0500 Message-ID: <1387923561-8724-1-git-send-email-b20788@freescale.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131224_052144_366385_3201821B X-CRM114-Status: GOOD ( 10.10 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [207.46.163.25 listed in list.dnswl.org] 1.9 DATE_IN_FUTURE_06_12 Date: is 6 to 12 hours after Received: date -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org Improve the comment of SW workaround for CCM lpm issue using hardware errata description to avoid confusion. ERR007265: CCM: When improper low-power sequence is used, the SoC enters low power mode before the ARM core executes WFI. Software workaround: 1) Software should trigger IRQ #32 (IOMUX) to be always pending by setting IOMUX_GPR1_GINT. 2) Software should then unmask IRQ #32 in GPC before setting CCM Low-Power mode. 3) Software should mask IRQ #32 right after CCM Low-Power mode is set (set bits 0-1 of CCM_CLPCR). Signed-off-by: Anson Huang --- arch/arm/mach-imx/pm-imx6q.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/arm/mach-imx/pm-imx6q.c b/arch/arm/mach-imx/pm-imx6q.c index aecd9f8..31cb9d6 100644 --- a/arch/arm/mach-imx/pm-imx6q.c +++ b/arch/arm/mach-imx/pm-imx6q.c @@ -156,10 +156,13 @@ int imx6q_set_lpm(enum mxc_cpu_pwr_mode mode) } /* - * Unmask the always pending IOMUXC interrupt #32 as wakeup source to - * deassert dsm_request signal, so that we can ensure dsm_request - * is not asserted when we're going to write CLPCR register to set LPM. - * After setting up LPM bits, we need to mask this wakeup source. + * ERR007265: + * CCM: When improper low-power sequence is used, the SoC enters low power mode before the ARM core executes WFI. + * + * Software workaround: + * 1) Software should trigger IRQ #32 (IOMUX) to be always pending by setting IOMUX_GPR1_GINT. + * 2) Software should then unmask IRQ #32 in GPC before setting CCM Low-Power mode. + * 3) Software should mask IRQ #32 right after CCM Low-Power mode is set (set bits 0-1 of CCM_CLPCR). */ iomuxc_irq_desc = irq_to_desc(32); imx_gpc_irq_unmask(&iomuxc_irq_desc->irq_data); @@ -219,6 +222,8 @@ void __init imx6q_pm_init(void) WARN_ON(!ccm_base); /* + * This is for SW workaround step #1 of ERR007265, see comments + * in imx6q_set_lpm for details of this errata. * Force IOMUXC irq pending, so that the interrupt to GPC can be * used to deassert dsm_request signal when the signal gets * asserted unexpectedly.