From patchwork Tue Dec 24 18:00:47 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Anson Huang X-Patchwork-Id: 3400371 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2C77EC0D4A for ; Tue, 24 Dec 2013 06:03:38 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5E5252072E for ; Tue, 24 Dec 2013 06:03:37 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 447E1206DD for ; Tue, 24 Dec 2013 06:03:36 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvL5R-0000pe-5Z; Tue, 24 Dec 2013 06:03:25 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvL5O-00075Z-MG; Tue, 24 Dec 2013 06:03:22 +0000 Received: from co1ehsobe002.messaging.microsoft.com ([216.32.180.185] helo=co1outboundpool.messaging.microsoft.com) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VvL5L-00074x-1k for linux-arm-kernel@lists.infradead.org; Tue, 24 Dec 2013 06:03:20 +0000 Received: from mail203-co1-R.bigfish.com (10.243.78.229) by CO1EHSOBE032.bigfish.com (10.243.66.97) with Microsoft SMTP Server id 14.1.225.22; Tue, 24 Dec 2013 06:02:50 +0000 Received: from mail203-co1 (localhost [127.0.0.1]) by mail203-co1-R.bigfish.com (Postfix) with ESMTP id 72E153A005E; Tue, 24 Dec 2013 06:02:50 +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 mail203-co1 (localhost.localdomain [127.0.0.1]) by mail203-co1 (MessageSwitch) id 1387864968236817_16045; Tue, 24 Dec 2013 06:02:48 +0000 (UTC) Received: from CO1EHSMHS003.bigfish.com (unknown [10.243.78.234]) by mail203-co1.bigfish.com (Postfix) with ESMTP id 34CB8580047; Tue, 24 Dec 2013 06:02:48 +0000 (UTC) Received: from mail.freescale.net (70.37.183.190) by CO1EHSMHS003.bigfish.com (10.243.66.13) with Microsoft SMTP Server (TLS) id 14.16.227.3; Tue, 24 Dec 2013 06:02:48 +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 06:02:46 +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 rBO62ib0012914; Mon, 23 Dec 2013 23:02:45 -0700 From: Anson Huang To: , Subject: [PATCH] ARM: imx: improve the comment of CCM lpm SW workaround Date: Tue, 24 Dec 2013 13:00:47 -0500 Message-ID: <1387908047-1848-1-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_010319_263754_848A223B X-CRM114-Status: GOOD ( 10.48 ) X-Spam-Score: -0.7 (/) 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-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, DATE_IN_FUTURE_06_12, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Improve the comment of SW workaround for CCM lpm issue using hardware errata description to avoid confusion. TKT194736: Chip will enter low power mode before ARM A9 CPU executes WFI when improper low power sequence is used. SW workaround: 1) SW will trigger irq #32(IOMUX) to be always pending manually by setting IOMUX_GPR1_GINT bit, 2) SW should then Unmask it in GPC before setting CCM LPM 3) SW should Mask it right after CCM LPM is set (set bit0-1 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..8da4732 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. + * TKT194736: + * Chip will enter low power mode before ARM A9 CPU executes WFI when improper low power sequence is used. + * + * SW workaround: + * 1) SW will trigger irq #32(IOMUXC) to be always pending manually by setting IOMUX_GPR1_GINT bit, + * 2) SW should then Unmask it in GPC before setting CCM LPM + * 3) SW should Mask it right after CCM LPM is set (set bit0-1 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 TKT194736, 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.