From patchwork Tue Jun 25 17:46:40 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leif Lindholm X-Patchwork-Id: 2778261 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 7F8B1C0AB1 for ; Tue, 25 Jun 2013 17:43:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5BFEB20349 for ; Tue, 25 Jun 2013 17:43:26 +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 F1AC920333 for ; Tue, 25 Jun 2013 17:43:24 +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 1UrXGT-0001aL-4X; Tue, 25 Jun 2013 17:42:49 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1UrXGG-0007IR-Vt; Tue, 25 Jun 2013 17:42:37 +0000 Received: from mail-wi0-f169.google.com ([209.85.212.169]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UrXFx-0007Fm-Ql for linux-arm-kernel@lists.infradead.org; Tue, 25 Jun 2013 17:42:18 +0000 Received: by mail-wi0-f169.google.com with SMTP id c10so1213909wiw.4 for ; Tue, 25 Jun 2013 10:41:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references :x-gm-message-state; bh=d/hzBIrTgFKmPCIcG/lzrBBBtcMX4aBKx2NNbfKcqQ0=; b=cJIoWs7GKtxMlHuP6Bce9Pq0m18c5VCXh/R7V0oCjK+m31svvkFMsVkbcrMS4RxAn9 bPCIBr2dR8GiQ83sn8bpCh19zc/U+hLcDmdIhiAXrI8a8n+55ALVZkL2nQeFw49CywEt T34ZMcFrNqNTyjQGDh15VlSYZRQ67/uAzVtbQhRjXl29tKF6o1MYKRf/kopfDqIJPmbe 2gqaQhocIK5bfPGwvT86L6b9I0cQkcPGl3zOVqkJ233UrARSPgwx9l4UlQ4eMGUnuMlw FbKJaf2308ua2LIHIFVsnJg2sfQpmdbmgEPmFxHOmDIrYJz2y155Zh8QnNHs4Ti3jZjH YC5A== X-Received: by 10.180.75.144 with SMTP id c16mr9893700wiw.1.1372182115334; Tue, 25 Jun 2013 10:41:55 -0700 (PDT) Received: from mohikan.mushroom.smurfnet.nu (cpc4-cmbg17-2-0-cust71.5-4.cable.virginmedia.com. [86.14.224.72]) by mx.google.com with ESMTPSA id u9sm5607332wif.6.2013.06.25.10.41.53 for (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 25 Jun 2013 10:41:54 -0700 (PDT) From: Leif Lindholm To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] Documentation: arm: early_ioremap Date: Tue, 25 Jun 2013 18:46:40 +0100 Message-Id: <1372182401-11029-2-git-send-email-leif.lindholm@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1372182401-11029-1-git-send-email-leif.lindholm@linaro.org> References: <1372182401-11029-1-git-send-email-leif.lindholm@linaro.org> X-Gm-Message-State: ALoCoQm/2ChzGXgcLPad8QpXjaJNdDVIKjjVCPQ7rn57VWGwe9zzxIhBKE65OCs10mri3WEiJLhb X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130625_134217_998571_5AB09C64 X-CRM114-Status: UNSURE ( 9.14 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.6 (--) Cc: nico@linaro.org, patches@linaro.org, linux-kernel@vger.kernel.org, Leif Lindholm , linux-doc@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=-5.5 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 This patch provides documentation of the early_ioremap() functionality, including its implementation and usage instructions. Signed-off-by: Leif Lindholm --- Documentation/arm/00-INDEX | 2 ++ Documentation/arm/early_ioremap.txt | 12 ++++++++++++ 2 files changed, 14 insertions(+) create mode 100644 Documentation/arm/early_ioremap.txt diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX index 36420e1..4978456 100644 --- a/Documentation/arm/00-INDEX +++ b/Documentation/arm/00-INDEX @@ -24,6 +24,8 @@ SPEAr - ST SPEAr platform Linux Overview VFP/ - Release notes for Linux Kernel Vector Floating Point support code +early_ioremap.txt + - documentation of the early_ioremap() functionality empeg/ - Ltd's Empeg MP3 Car Audio Player mem_alignment diff --git a/Documentation/arm/early_ioremap.txt b/Documentation/arm/early_ioremap.txt new file mode 100644 index 0000000..178f791 --- /dev/null +++ b/Documentation/arm/early_ioremap.txt @@ -0,0 +1,12 @@ +early_ioremap() and early_iounmap() rovide a mechanism for temporarily mapping +in small blocks of memory, identified by their physical address, into the +fixmap virtual address block before paging_init() has been called and more +flexible mapping functions are available. + +Due to its direct method, it also gets around potential need for special +handling of regions that end up in highmem. + +It supports up to 7 simultaneously mapped regions of up to 128KB each. +All regions are mapped as non-shareable device memory. + +Specify 'early_ioremap_debug' on the kernel commandline for verbose output.