Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751038Ab3IFJUd (ORCPT ); Fri, 6 Sep 2013 05:20:33 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:56242 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750922Ab3IFJUW (ORCPT ); Fri, 6 Sep 2013 05:20:22 -0400 From: Leif Lindholm To: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, arnd@arndb.de, nico@linaro.org, Leif Lindholm 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> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2387 Lines: 62 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); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/