From patchwork Tue Mar 14 08:38:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nicolas Ferre X-Patchwork-Id: 9622743 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 58AC860424 for ; Tue, 14 Mar 2017 08:37:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 449A928517 for ; Tue, 14 Mar 2017 08:37:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 36A762851F; Tue, 14 Mar 2017 08:37:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A860828517 for ; Tue, 14 Mar 2017 08:37:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=GGPrQE8LEq3fswEQ4bgQGOYKVcPFTqHQ/nuOO9RSZfg=; b=tHlYcEJ+1YCTAN LY3JClGSoaFOXjdPgIMUXxVlyCIGr5vxki55okczwhy+siEXQcJufTRgkhh+6KGW8SBtc565SuXFi P7iEjQFUljYHR/x3xHpne6l8gaqx4UJ6yRfxON+yEPcIKmOqE8/2+N87aEhQ6KWMoUgrVmAKk9I+T k6cRi9ZaaKbTtI9DHQtaDC712ynreUInkDKugy4nBqha8u0JkIXCiHIgntdNvYUhed+PbpumLO8Oh uiVY+SeqCcSg+IUABBPa7i92q+81Oez1tBK5WgqUR3OuNj5iymQAGAzxcbcX/pnFvXsOL7gWyfAEy Yand3xBdtANTohMCRhYQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cnhxh-0004EA-99; Tue, 14 Mar 2017 08:37:45 +0000 Received: from exsmtp01.microchip.com ([198.175.253.37] helo=email.microchip.com) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cnhxd-0004CQ-M8 for linux-arm-kernel@lists.infradead.org; Tue, 14 Mar 2017 08:37:43 +0000 Received: from tenerife.corp.atmel.com (10.10.76.4) by CHN-SV-EXCH01.mchp-main.com (10.10.76.37) with Microsoft SMTP Server id 14.3.181.6; Tue, 14 Mar 2017 01:37:20 -0700 From: Nicolas Ferre To: Alexandre Belloni , Boris BREZILLON , Wenyou Yang , Subject: [PATCH v2] ARM: at91: pm: cpu_idle: switch DDR to power-down mode Date: Tue, 14 Mar 2017 09:38:04 +0100 Message-ID: <20170314083804.1756-1-nicolas.ferre@microchip.com> X-Mailer: git-send-email 2.9.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170314_013741_761373_82227BE2 X-CRM114-Status: GOOD ( 11.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, "# v4 . 1+" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP On some DDR controllers, compatible with the sama5d3 one, the sequence to enter/exit/re-enter the self-refresh mode adds more constrains than what is currently written in the at91_idle driver. An actual access to the DDR chip is needed between exit and re-enter of this mode which is somehow difficult to implement. This sequence can completely hang the SoC. It is particularly experienced on parts which embed a L2 cache if the code run between IDLE calls fits in it... Moreover, as the intention is to enter and exit pretty rapidly from IDLE, the power-down mode is a good candidate. So now we use power-down instead of self-refresh. As we can simplify the code for sama5d3 compatible DDR controllers, we instantiate a new sama5d3_ddr_standby() function. Signed-off-by: Nicolas Ferre Cc: # v4.1+ Fixes: 017b5522d5e3 ("ARM: at91: Add new binding for sama5d3-ddramc") --- arch/arm/mach-at91/pm.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 3d89b7905bd9..a277981f414d 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -289,6 +289,22 @@ static void at91_ddr_standby(void) at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1); } +static void sama5d3_ddr_standby(void) +{ + u32 lpr0; + u32 saved_lpr0; + + saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR); + lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB; + lpr0 |= AT91_DDRSDRC_LPCB_POWER_DOWN; + + at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0); + + cpu_do_idle(); + + at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0); +} + /* We manage both DDRAM/SDRAM controllers, we need more than one value to * remember. */ @@ -323,7 +339,7 @@ static const struct of_device_id const ramc_ids[] __initconst = { { .compatible = "atmel,at91rm9200-sdramc", .data = at91rm9200_standby }, { .compatible = "atmel,at91sam9260-sdramc", .data = at91sam9_sdram_standby }, { .compatible = "atmel,at91sam9g45-ddramc", .data = at91_ddr_standby }, - { .compatible = "atmel,sama5d3-ddramc", .data = at91_ddr_standby }, + { .compatible = "atmel,sama5d3-ddramc", .data = sama5d3_ddr_standby }, { /*sentinel*/ } };