From patchwork Fri Jun 6 21:43:05 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 4313631 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 6D38EBEEAA for ; Fri, 6 Jun 2014 21:46:58 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9C566201F7 for ; Fri, 6 Jun 2014 21:46:57 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (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 C280A201C8 for ; Fri, 6 Jun 2014 21:46:56 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wt1vK-0007oJ-JI; Fri, 06 Jun 2014 21:43:42 +0000 Received: from mail-vc0-f201.google.com ([209.85.220.201]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wt1vH-0007nU-LV for linux-arm-kernel@lists.infradead.org; Fri, 06 Jun 2014 21:43:40 +0000 Received: by mail-vc0-f201.google.com with SMTP id hq11so671671vcb.0 for ; Fri, 06 Jun 2014 14:43:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=yhKH/SgT5lIf9fWqIv4ejj3JrIYqYgIV+WZuihrekSg=; b=jF6KtVHysPcRd9fb83cPTcFDEgYmGwRkrZeGMIUzw20TEzX1AvU9X53iU94vxnxjLo eawwTOdkabb5V2TnBL1kM8Yv1ohVvZi2fFPHztylCe1Y9L8WhMf4nT7XwQJnv15mdGJa 0wSXXTduhywY67jB17MdJNg356HNzFpa4sbReBiZPRjK7tUispp9t3p6N9GFFGTpBmZ3 nAUwJN+tJnbKdLuVbbCP4l1eEIHqXKFtMJHUSKMv/BqakScMTn0sC2qtpdlKJy3DU96V CMrG4H3QeTkDS2swbU6IAcjR1TWEuK2QhUo1/J6OElQBoTJCSn2jwvlAu5+J/jO+OgVs 5aqA== X-Gm-Message-State: ALoCoQkji5OaNWs7tbtGgWT3ajHo+xp094OCDniyzczqj+w6oA4AHhGf1tzmlgpjC5DEzTtzNOIu X-Received: by 10.58.187.68 with SMTP id fq4mr5209178vec.0.1402090997997; Fri, 06 Jun 2014 14:43:17 -0700 (PDT) Received: from corp2gmr1-2.hot.corp.google.com (corp2gmr1-2.hot.corp.google.com [172.24.189.93]) by gmr-mx.google.com with ESMTPS id l7si739631vda.3.2014.06.06.14.43.17 for (version=TLSv1.1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 06 Jun 2014 14:43:17 -0700 (PDT) Received: from tictac.mtv.corp.google.com (tictac.mtv.corp.google.com [172.22.72.141]) by corp2gmr1-2.hot.corp.google.com (Postfix) with ESMTP id A54DB5A4629; Fri, 6 Jun 2014 14:43:17 -0700 (PDT) Received: by tictac.mtv.corp.google.com (Postfix, from userid 121310) id 4170A81033; Fri, 6 Jun 2014 14:43:17 -0700 (PDT) From: Doug Anderson To: Kukjin Kim , Nicolas Pitre Subject: [PATCH] ARM: EXYNOS: mcpm: Don't rely on firmware's secondary_cpu_start Date: Fri, 6 Jun 2014 14:43:05 -0700 Message-Id: <1402090985-8061-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.0.0.526.g5318336 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140606_144339_775180_F7CE5108 X-CRM114-Status: GOOD ( 16.94 ) X-Spam-Score: -1.4 (-) Cc: Tushar Behera , linux@arm.linux.org.uk, Kevin Hilman , Andrew Bresticker , Inderpal Singh , Doug Anderson , linux-kernel@vger.kernel.org, olof@lixom.net, Thomas Abraham , linux-arm-kernel@lists.infradead.org, Abhilash Kesavan , Javier Martinez Canillas , linux-samsung-soc@vger.kernel.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: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00,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 On exynos mcpm systems the firmware is hardcoded to jump to an address in SRAM (0x02073000) when secondary CPUs come up. By default the firmware puts a bunch of code at that location. That code expects the kernel to fill in a few slots with addresses that it uses to jump back to the kernel's entry point for secondary CPUs. Originally (on prerelease hardware) this firmware code contained a bunch of workarounds to deal with boot ROM bugs. However on all shipped hardware we simply use this code to redirect to a kernel function for bringing up the CPUs. Let's stop relying on the code provided by the bootloader and just plumb in our own (simple) code jump to the kernel. This has the nice benefit of fixing problems due to the fact that older bootloaders (like the one shipped on the Samsung Chromebook 2) might have put slightly different code into this location. Once suspend/resume is implemented for systems using exynos-mcpm we'll need to make sure we reinstall our fixed up code after resume. ...but that's not anything new since IRAM (and thus the address of the mcpm_entry_point) is lost across suspend/resume anyway. Signed-off-by: Doug Anderson --- arch/arm/mach-exynos/mcpm-exynos.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c index 0498d0b..3a7fad0 100644 --- a/arch/arm/mach-exynos/mcpm-exynos.c +++ b/arch/arm/mach-exynos/mcpm-exynos.c @@ -343,11 +343,13 @@ static int __init exynos_mcpm_init(void) pr_info("Exynos MCPM support installed\n"); /* - * Future entries into the kernel can now go - * through the cluster entry vectors. + * U-Boot SPL is hardcoded to jump to the start of ns_sram_base_addr + * as part of secondary_cpu_start(). Let's redirect it to the + * mcpm_entry_point(). */ - __raw_writel(virt_to_phys(mcpm_entry_point), - ns_sram_base_addr + MCPM_BOOT_ADDR_OFFSET); + __raw_writel(0xe59f0000, ns_sram_base_addr); /* ldr r0, [pc, #0] */ + __raw_writel(0xe12fff10, ns_sram_base_addr + 4); /* bx r0 */ + __raw_writel(virt_to_phys(mcpm_entry_point), ns_sram_base_addr + 8); iounmap(ns_sram_base_addr);