From patchwork Thu Aug 1 18:17:13 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Santosh Shilimkar X-Patchwork-Id: 2837199 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id BD8479FA4C for ; Thu, 1 Aug 2013 18:18:07 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8C1F120352 for ; Thu, 1 Aug 2013 18:18:06 +0000 (UTC) Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 38BA920350 for ; Thu, 1 Aug 2013 18:18:05 +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 1V4xRq-0000rN-DD; Thu, 01 Aug 2013 18:18:02 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1V4xRo-0002oD-0q; Thu, 01 Aug 2013 18:18:00 +0000 Received: from bear.ext.ti.com ([192.94.94.41]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1V4xRl-0002n6-G2 for linux-arm-kernel@lists.infradead.org; Thu, 01 Aug 2013 18:17:58 +0000 Received: from dlelxv90.itg.ti.com ([172.17.2.17]) by bear.ext.ti.com (8.13.7/8.13.7) with ESMTP id r71IHS0G027281; Thu, 1 Aug 2013 13:17:29 -0500 Received: from DLEE70.ent.ti.com (dlee70.ent.ti.com [157.170.170.113]) by dlelxv90.itg.ti.com (8.14.3/8.13.8) with ESMTP id r71IHSKi024620; Thu, 1 Aug 2013 13:17:28 -0500 Received: from dlelxv22.itg.ti.com (172.17.1.197) by DLEE70.ent.ti.com (157.170.170.113) with Microsoft SMTP Server id 14.2.342.3; Thu, 1 Aug 2013 13:17:28 -0500 Received: from ula0393909.am.dhcp.ti.com (ula0393909.am.dhcp.ti.com [158.218.103.117]) by dlelxv22.itg.ti.com (8.13.8/8.13.8) with ESMTP id r71IHRPY030923; Thu, 1 Aug 2013 13:17:28 -0500 From: Santosh Shilimkar To: Subject: [PATCH] ARM: Update SMP_ON_UP code to detect A9MPCore with 1 CPU devices Date: Thu, 1 Aug 2013 14:17:13 -0400 Message-ID: <1375381033-13220-1-git-send-email-santosh.shilimkar@ti.com> X-Mailer: git-send-email 1.7.9.5 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130801_141757_636944_012BC5DF X-CRM114-Status: GOOD ( 11.52 ) X-Spam-Score: -8.4 (--------) Cc: Russell King , linux-omap@vger.kernel.org, Will Deacon , Santosh Shilimkar , Vaibhav Bedia 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=-5.7 required=5.0 tests=BAYES_00, 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 From: Vaibhav Bedia The generic code is well equipped to differentiate between SMP and UP configurations.However, there are some devices which use Cortex-A9 MP core IP with 1 CPU as configuration. To let these SOCs to co-exist in a CONFIG_SMP=y build by leveraging the SMP_ON_UP support, we need to additionally check the number the cores in Cortex-A9 MPCore configuration. Without such a check in place, the startup code tries to execute ALT_SMP() set of instructions which lead to CPU faults. The issue was spotted on TI's Aegis device and this patch makes now the device work with omap2plus_defconfig which enables SMP by default. The change is kept limited to only Cortex-A9 MPCore detection code. Cc: Will Deacon Cc: Russell King Acked-by: Sricharan R Signed-off-by: Vaibhav Bedia Signed-off-by: Santosh Shilimkar --- arch/arm/kernel/head.S | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 9cf6063..4924b11 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -486,7 +486,23 @@ __fixup_smp: mrc p15, 0, r0, c0, c0, 5 @ read MPIDR and r0, r0, #0xc0000000 @ multiprocessing extensions and teq r0, #0x80000000 @ not part of a uniprocessor system? - moveq pc, lr @ yes, assume SMP + bne __fixup_smp_on_up @ no, assume UP + + @ Core indicates it is SMP. Check for Aegis SOC where a single + @ Cortex-A9 CPU is present but SMP operations fault. + mov r4, #0x41000000 + orr r4, r4, #0x0000c000 + orr r4, r4, #0x00000090 + teq r3, r4 @ Check for ARM Cortex-A9 + movne pc, lr @ Not ARM Cortex-A9, + + mrc p15, 4, r0, c15, c0 @ get SCU base address + teq r0, #0x0 @ '0' on actual UP A9 hardware + beq __fixup_smp_on_up @ So its an A9 UP + ldr r0, [r0, #4] @ read SCU Config + and r0, r0, #0x3 @ number of CPUs + teq r0, #0x0 @ is 1? + movne pc, lr __fixup_smp_on_up: adr r0, 1f