From patchwork Fri Sep 6 09:19:17 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leif Lindholm X-Patchwork-Id: 2854449 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 9C1949F3DC for ; Fri, 6 Sep 2013 09:21:16 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5D79720299 for ; Fri, 6 Sep 2013 09:21:15 +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 0FE7A20292 for ; Fri, 6 Sep 2013 09:21:14 +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 1VHsDn-000079-3h; Fri, 06 Sep 2013 09:20:55 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VHsDg-0002wm-AC; Fri, 06 Sep 2013 09:20:48 +0000 Received: from mail-wi0-f173.google.com ([209.85.212.173]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VHsDb-0002uZ-G2 for linux-arm-kernel@lists.infradead.org; Fri, 06 Sep 2013 09:20:45 +0000 Received: by mail-wi0-f173.google.com with SMTP id hq15so601777wib.6 for ; Fri, 06 Sep 2013 02:20:21 -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:in-reply-to :references; bh=L8eX+qOoxXpX8eF5YOuLUvuE3cHnedqJIcsKk1zOmdE=; b=YhmLCUEsK1bfL4+GajuBqQ+MEZ97vchd44Gvrd/rLpGl4bysmPZL+cUqMiqhzcI/ld q6ZeXrTovZVJhCZ+mQ/fQam9fSzBxq7bB87mM9BM72mYonNGIJ+fXJzdbDuk/w/bSdpm MIX6mX8+m6VE1Wo0sXunHv4p+qtxxQSTrw/lek8KMZNjkVKEFd506QsX2Ka/FONRvD5E MHfs5vsk++4FiBf9zPgVymTYxPorLtDsPiEtLVuxUcdluDBHcnjmboRS3F2YksY3gMfi V4pEEdt6PEASLrwjf5Q+3kecNSuM5FrxLiUfUu+dCsnSPcGJJGs0j2wxpyaPNhgcIq1F ShOQ== X-Gm-Message-State: ALoCoQmPX1yCJOjpTSm58p1U8N0qq1g+LW5Mggc/7tuMUuxDFqGiNz0SKlpa1uldEhyxHrxIA/b/ X-Received: by 10.180.12.45 with SMTP id v13mr9414112wib.57.1378459221906; Fri, 06 Sep 2013 02:20:21 -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 fv10sm17484066wic.0.1969.12.31.16.00.00 (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 06 Sep 2013 02:20:20 -0700 (PDT) From: Leif Lindholm To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/2] Documentation: arm: early_ioremap/early_memremap Date: Fri, 6 Sep 2013 10:19:17 +0100 Message-Id: <1378459158-2145-2-git-send-email-leif.lindholm@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1378459158-2145-1-git-send-email-leif.lindholm@linaro.org> References: <1378459158-2145-1-git-send-email-leif.lindholm@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130906_052043_750911_53DBA82A X-CRM114-Status: UNSURE ( 9.52 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -2.6 (--) Cc: Leif Lindholm , nico@linaro.org, linux-kernel@vger.kernel.org, arnd@arndb.de, 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=-6.6 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() and early_memremap() functionality,including its implementation and usage instructions. Signed-off-by: Leif Lindholm Acked-by: Rob Landley --- Documentation/arm/00-INDEX | 2 ++ Documentation/arm/early_ioremap.txt | 23 +++++++++++++++++++++++ 2 files changed, 25 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..e1c0b16 --- /dev/null +++ b/Documentation/arm/early_ioremap.txt @@ -0,0 +1,23 @@ +early_ioremap()/early_memremap() and early_iounmap() provide 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 run +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 mappings created by early_ioremap() are non-shareable device memory. +All mappings created by early_memremap() are uncached normal memory. + +Any residual mappings will be overridden by subsequent kmap() calls (but do +use early_iounmap()). + +Specify 'early_ioremap_debug' on the kernel commandline for verbose output. + +SYNOPSIS + #include + + void *early_ioremap(resource_size_t phys_addr, unsigned long size); + void *early_memremap(resource_size_t phys_addr, unsigned long size); + void early_iounmap(void *addr, unsigned long size);