From patchwork Fri Dec 2 15:05:43 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Murzin X-Patchwork-Id: 9458775 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 45FD560236 for ; Fri, 2 Dec 2016 15:19:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 392E5284E2 for ; Fri, 2 Dec 2016 15:19:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2E0202855C; Fri, 2 Dec 2016 15:19:04 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id A1B76284E2 for ; Fri, 2 Dec 2016 15:19:03 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1cCpaT-0007XU-Hv; Fri, 02 Dec 2016 15:17:21 +0000 Received: from casper.infradead.org ([2001:770:15f::2]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1cCpQG-00056Q-8V for linux-arm-kernel@bombadil.infradead.org; Fri, 02 Dec 2016 15:06:48 +0000 Received: from foss.arm.com ([217.140.101.70]) by casper.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1cCpQC-0002qH-98 for linux-arm-kernel@lists.infradead.org; Fri, 02 Dec 2016 15:06:46 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D98F51596; Fri, 2 Dec 2016 07:06:19 -0800 (PST) Received: from bc-a7-1-1.euhpc.arm.com. (bc-a7-1-1.euhpc.arm.com [10.6.3.165]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 113EE3F24D; Fri, 2 Dec 2016 07:06:17 -0800 (PST) From: Vladimir Murzin To: linux-arm-kernel@lists.infradead.org Subject: [RFC v3 PATCH 25/25] ARM: Allow ARCH_MULTIPLATFORM to be selected for NOMMU Date: Fri, 2 Dec 2016 15:05:43 +0000 Message-Id: <1480691143-19845-26-git-send-email-vladimir.murzin@arm.com> X-Mailer: git-send-email 2.0.0 In-Reply-To: <1480691143-19845-1-git-send-email-vladimir.murzin@arm.com> References: <1480691143-19845-1-git-send-email-vladimir.murzin@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20161202_150644_651185_F495F3BD X-CRM114-Status: GOOD ( 16.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ryan Mallon , arnd@arndb.de, Tony Lindgren , Linus Walleij , Russell King , Alexander Shiyan , Hartley Sweeten , Thierry Reding , Sascha Hauer , Fabio Estevam , Shawn Guo MIME-Version: 1.0 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 With this patch applied potentially any platform can be built in NOMMU configurations if CONFIG_EXPERT is selected. However, there is no guarantee that platform can successfully run such Image. So the main motivation behind of this patch: - bring build coverage for NOMMU configurations - allow known working NOMMU platforms (like R-class) to be used - pave a way to add support for single address space (aka 1:1 mapping) for MMU platforms, so they can be usable in NOMMU configurations Cc: Hartley Sweeten Cc: Ryan Mallon Cc: Tony Lindgren Cc: Thierry Reding Cc: Alexander Shiyan Cc: Shawn Guo Cc: Sascha Hauer Cc: Fabio Estevam Cc: Linus Walleij Cc: Russell King Signed-off-by: Vladimir Murzin --- arch/arm/Kconfig | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index b3fa6e9..9c90b81 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -327,9 +327,9 @@ choice config ARCH_MULTIPLATFORM bool "Allow multiple platforms to be selected" - depends on MMU + depends on MMU || EXPERT select ARM_HAS_SG_CHAIN - select ARM_PATCH_PHYS_VIRT + select ARM_PATCH_PHYS_VIRT if MMU select AUTO_ZRELADDR select CLKSRC_OF select COMMON_CLK @@ -339,6 +339,23 @@ config ARCH_MULTIPLATFORM select PCI_DOMAINS if PCI select SPARSE_IRQ select USE_OF + help + Please, read carefully if you've selected CONFIG_MMU=n! + + Multiplatform with !MMU configuration *is not* meant that + kernel built to support every platform will boot on them. It + is because physical address space layouts (particularly where + RAM is located) are different between platforms and there is + no MMU to work that around. + + You must specify where RAM start (via DRAM_BASE config + option) and appropriate size of RAM (via DRAM_SIZE config + option) which are valid for the platform you are building + for. + + This feature is *EXPERIMENTAL*, please, consider building + with CONFIG_MMU=y unless you know what you do or want to + help with testing. config ARM_SINGLE_ARMV7M bool "ARMv7-M based platforms (Cortex-M0/M3/M4)"