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[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 Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, patches@linaro.org, nico@linaro.org, Leif Lindholm 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: ALoCoQnv/S8xz03n+x/Ck91rJJpsHW/XoASbzDg7ChJV+lOizY4tb+AZxqiGchsDgnpqzr9w9MtC X-Original-Sender: leif.lindholm@linaro.org X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 2607:f8b0:400c:c01::235 is neither permitted nor denied by best guess record for domain of patch+caf_=patchwork-forward=linaro.org@linaro.org) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , 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.