From patchwork Thu Oct 3 09:49:15 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leif Lindholm X-Patchwork-Id: 2981851 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 2F0E19F288 for ; Thu, 3 Oct 2013 09:52:04 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8A3B420272 for ; Thu, 3 Oct 2013 09:51:59 +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 51865201F4 for ; Thu, 3 Oct 2013 09:51:58 +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 1VRfZK-0004Ok-Ix; Thu, 03 Oct 2013 09:51:38 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VRfZE-0005OA-VW; Thu, 03 Oct 2013 09:51:32 +0000 Received: from mail-wg0-f52.google.com ([74.125.82.52]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1VRfZ3-0005LF-FV for linux-arm-kernel@lists.infradead.org; Thu, 03 Oct 2013 09:51:22 +0000 Received: by mail-wg0-f52.google.com with SMTP id m15so2160728wgh.31 for ; Thu, 03 Oct 2013 02:51:00 -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=R82n7Ba+RUUe5Qe0OEZ+tSVhO2ZkL9Eg65YaI7/9dmo=; b=OyGlHMSeFwuP2l8XGTng094BEKXxAvH6W1/J47fYfeAS8Agy2VcXvY514o/6Uq12zx yBvwJ6CJXopA1lSm8fyXoVooy6vPXbUduzU1ifdD6AOb9iN3Lt+Vb9OE5oTdypnexGOh nOB1FoOgW3Ict/nkp8/tcNtSM+betusQf7HAFX94y4fEwY2DzIXe9HQiMgtdamfKTsly M13a24rr4A9kClGK5VSfC0YAp5h2NDOoAdO/cKNBfRrsESFOYzxW5QnA91eE1bG/PzSC OMcWiLrWkt27AEIRJ2wFn8+b/wUPGDTdQ19rWwsHD/Ve5IQPVK4sRhbW34KWPenCLBPe TadQ== X-Gm-Message-State: ALoCoQl84uh4vibHMNPii5GLFy5VxOsAcSmcfoUDTWkYRvW4FiAxrzAb8AUHv+cw/cc8NtgVu3K6 X-Received: by 10.194.23.196 with SMTP id o4mr631803wjf.62.1380793859894; Thu, 03 Oct 2013 02:50:59 -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 fb9sm12112888wid.7.1969.12.31.16.00.00 (version=TLSv1.2 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 03 Oct 2013 02:50:59 -0700 (PDT) From: Leif Lindholm To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v3 1/2] Documentation: arm: early_ioremap/early_memremap Date: Thu, 3 Oct 2013 10:49:15 +0100 Message-Id: <1380793756-2562-2-git-send-email-leif.lindholm@linaro.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1380793756-2562-1-git-send-email-leif.lindholm@linaro.org> References: <1380793756-2562-1-git-send-email-leif.lindholm@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20131003_055121_610858_35052D33 X-CRM114-Status: GOOD ( 10.35 ) X-Spam-Score: -2.6 (--) Cc: Catalin Marinas , Nicolas Pitre , 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=-4.9 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. Cc: linux-doc@vger.kernel.org Cc: Nicolas Pitre Cc: Arnd Bergman Cc: Catalin Marinas 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..6096cfa --- /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);